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Background: Campylobacter jejuni is the leading cause of human bacterial gastroenteritis worldwide. However, systemic infection with C. jejuni is uncommon, and osteomyelitis caused by C. jejuni is extremely rare. Cultivation from spinal bone biopsies has not previously been reported in the literature. Case presentation: A 79-year-old immunocompetent male was admitted to the emergency department at Aalborg University Hospital in Denmark with lower back pain, fever and diarrhoea. A FecalSwab obtained upon admission was PCR-positive for Campylobacter spp, while an aerobic blood culture bottle was positive for C. jejuni (Time to detection: 70.4 h). A MRI of columna totalis showed osteomyelitis at L1/L2 with an epidural abscess from L1 to L2 with compression of the dura sack. The patient underwent spinal surgery with spondylodesis and decompression of L1/L2. The surgery was uncomplicated and the discus material was also culture positive for C. jejuni. The patient was treated with meropenem for a total duration of four weeks, followed by four weeks of oral treatment with clindamycin in tapered dosage. The patient recovered quickly following surgery and targeted antibiotic treatment with decreasing lumbar pain and biochemical response and was fully recovered at follow-up three months after end of treatment. Conclusions: While C. jejuni osteomyelitis is rare, it should still be suspected as a possible causative bacterial aetiology in patients with vertebral osteomyelitis, in particular when symptoms of diarrhoea is involved in the clinical presentation. Susceptibility testing is crucial due to emerging resistance, and targeted treatment strategies should rely upon such tests. [ABSTRACT FROM AUTHOR]

Antibiotic resistant and biofilm forming uropathogenic Enterobacteriaceae are rising. This study was conducted to evaluate the efflux pump and plasmid mediated efflux genes in ciprofloxacin (CIP) resistant hospital acquired uropathogenic Escherichia coli and Klebsiella pneumoniae. Also, to assess the anti-biofilm action of carbonyl cyanide m-chlorophenylhydrazone (CCCP). Uropathogenic E. coli and K. pneumoniae isolates were collected from Mansoura University Hospitals in Mansoura, Egypt. The effect of Sub- minimum inhibitory concentration (MIC) of CCCP on CIP MIC was evaluated and the MIC decrease factor (MDF) was calculated. The presence of oqxAB and qepA genes was detected by PCR. The effect CCCP on biofilm was detected in strong biofilm formers. 56 and 47 CIP-resistant uropathogenic E. coli and K. pneumoniae isolates respectively were detected. Significant MDF by CCCP was observed in 55.3% of these isolates. The qepA gene was only present in E. coli. However, oqxAB genes were found only in K. pneumoniae. Biofilm formation was detected in 58.9% and 72.3% of CIP-resistant E. coli and K. pneumoniae isolates, respectively. Biofilm formation was significantly decreased by CCCP. According to these findings, CIP resistance and plasmid-mediated efflux pumps in uropathogenic E. coli and K. pneumoniae are of rising concern. Efflux pump inhibitor CCCP represents a possible option to decrease the biofilm formation in these resistant urinary pathogens.

Salmonella enterica is an important foodborne pathogen worldwide. Ciprofloxacin and extended-spectrum cephalosporins are the common first-line antimicrobial drugs for the treatment of salmonellosis, antimicrobial resistance genes for which are mostly transferred via plasmids. The goal of this work was to perform genomic analysis of plasmids from foodborne S. enterica isolates obtained in Russia based on whole-genome sequencing. In the current study, 11 multidrug-resistant samples isolated in 2021 from 8 regions of Russia were selected based on their resistance to ciprofloxacin and third-generation cephalosporins (CIP-3rd). Whole-genome short-read sequencing (WGS) was performed for all isolates; the samples belonged to five different sequence types (ST32, ST469, ST11, ST142, and ST548) which had different profiles of antimicrobial resistance (AMR) and virulence genes. We have performed additional long-read sequencing of four representative S. enterica isolates, which showed that they carried pESI-like megaplasmids of 202–280 kb length harboring extended-spectrum β-lactamase genes, fluoroquinolone, tetracycline, and aminoglycosides resistance genes, as well as several virulence determinants. We believe that the WGS data obtained will greatly facilitate further studies of foodborne S. enterica isolates epidemiology in terms of their self-transmissible plasmid composition that mediated antimicrobial resistance and virulence determinants conferring selective advantages of this important bacterial pathogen. [ABSTRACT FROM AUTHOR]

Pseudomonas aeruginosa is a ubiquitous pathogen that causes a wide range of acute and chronic infections. Ciprofloxacin, one of the first-line fluoroquinolone class antibiotics, is commonly used for the treatment of P. aeruginosa infections. However, ciprofloxacin-resistant P. aeruginosa is increasingly reported worldwide, making treatment difficult. To determine resistance-related mutations, we conducted an experimental evolution using a previously identified ciprofloxacin-resistant P. aeruginosa clinical isolate, CRP42. The evolved mutants could tolerate a 512-fold higher concentration of ciprofloxacin than CRP42. Genomic DNA reference mapping was performed, which revealed mutations in genes known to be associated with ciprofloxacin resistance as well as in those not previously linked to ciprofloxacin resistance, including the ParER586W substitution and PA0625 frameshift insertion. Simulation of the ParER586W substitution and PA0625 frameshift insertion by gene editing in CRP42 and the model strain PAO1 demonstrated that while the PA0625 mutation does contribute to resistance, mutation in the ParER586W does not contribute to resistance but rather affects tolerance against ciprofloxacin. These findings advance our understanding of ciprofloxacin resistance in P. aeruginosa. [ABSTRACT FROM AUTHOR]

Antibiotic resistant and biofilm forming uropathogenic enterobacteriaceae are rising. this study was conducted to evaluate the efflux pump and plasmid mediated efflux genes in ciprofloxacin (CIP) resistant hospital acquired uropathogenic Escherichia coli and Klebsiella pneumoniae. Also, to assess the anti-biofilm action of carbonyl cyanide m-chlorophenylhydrazone (CCCP). Uropathogenic E. coli and K. pneumoniae isolates were collected from Mansoura University Hospitals in Mansoura, egypt. the effect of Sub- minimum inhibitory concentration (MiC) of CCCP on CIP MIC was evaluated and the MIC decrease factor (MDF) was calculated. the presence of oqxAB and qepA genes was detected by PCR. the effect CCCP on biofilm was detected in strong biofilm formers. 56 and 47 CIP-resistant uropathogenic E. coli and K. pneumoniae isolates respectively were detected. Significant MDF by CCCP was observed in 55.3% of these isolates. the qepA gene was only present in E. coli. However, oqxAB genes were found only in K. pneumoniae. Biofilm formation was detected in 58.9% and 72.3% of CIP-resistant E. coli and K. pneumoniae isolates, respectively. Biofilm formation was significantly decreased by CCCP. According to these findings, CIP resistance and plasmid-mediated efflux pumps in uropathogenic E. coli and K. pneumoniae are of rising concern. efflux pump inhibitor CCCP represents a possible option to decrease the biofilm formation in these resistant urinary pathogens. [ABSTRACT FROM AUTHOR]

Kitchawan Hengkrawit,1 Chidchanok Tangjade2 1Pediatric Infectious Disease Unit, Department of Pediatrics, Panyananthaphikkhu Chonprathan Medical Center, Srinakarinwirot University, Nonthaburi, Thailand; 2Pediatrics Gastroenterology and Hepatology Unit, Department of Pediatrics, Panyananthaphikkhu Chonprathan Medical Center, Srinakarinwirot University, Nonthaburi, ThailandCorrespondence: Kitchawan Hengkrawit, Pediatric Infectious Disease unit, Department of Pediatrics, Panyananthaphikkhu Chonprathan Medical Center, Srinakarinwirot University, P.O.Box: 222 Moo 1, Tiwanon Road, Pak Kret, Nonthaburi, 11120, Thailand, Tel +66 2 502 2345, Fax +662 502-2305, Email Kitchawan5007@gmail.comPurpose: Multi-drug resistance of non-typhoidal Salmonella (MDR-NTS) is an increasing threat worldwide. In Thailand, data for the past decade is limited. This research is to determine the prevalence and trends of nonsusceptibility patterns of the bacteria, especially to ciprofloxacin and ceftriaxone.Methods: This retrospective study was extracted data of patients who had non-typhoidal Salmonella (NTS) infection, from 10 hospitals between June 2011 and June 2020. Demographic data, culture reports, and antimicrobial susceptibility were included in the analysis.Results: A total of 433 patients were identified. The most common age group was less than 15 years old (53.6%), with a median age of 12 years (IQR 57– 4). Of these people, 61.1% had gastroenteritis and 36.7% had bacteremia. The most prevalent serogroups was C (28.6%). MDR-NTS rate was 52.8% (95% CI 39– 44). The resistant rates were 43%, 32.8%, 22.8%, 6.7%, 4%, 0.45%, 0.45% for sulfamethoxazole/trimethoprim, amoxicillin-clavulanic acid, cefotaxime, ampicillin/sulbactam, piperacillin/tazobactam, imipenem and meropenem retrospectively. Resistant rates have been increasing, especially for ciprofloxacin (30%), which rose from 16.6% in 2011– 2015 to 39.5% in 2016– 2020 (prevalence rate ratio (PRR) 2.4,95% CI 1.51– 3.72) and for ceftriaxone 25.4% which rose from 16.1% to 32% (PRR 2 95% CI 1.24– 3.16). Ampicillin, norfloxacin, tetracycline, amikacin, gentamicin, and ceftazidime remained static at 62.3%, 49.5%, 33.2%, 15.2%, 8.8%, 2.8%, respectively.Conclusion: The prevalence of MDR-NTS has been increasing over the past decade, particularly those strains which demonstrate resistance to ciprofloxacin and ceftriaxone. Finding successful treatment requires a comprehensive selection of proper antimicrobials as well as close monitoring, especially in cases with severe infection.Keywords: multi-drug resistance, non-typhoidal Salmonella, drug-resistance pattern, ceftriaxone resistance, ciprofloxacin resistance, prevalence

Ashagrachew Tewabe Yayehrad,1,2 Gebremariam Birhanu Wondie,1 Tesfa Marew1 1Department of Pharmaceutics and Social Pharmacy, School of Pharmacy, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia; 2Department of Pharmacy, College of Medicine and Health Sciences, Bahir Dar University, Bahir Dar, EthiopiaCorrespondence: Ashagrachew Tewabe Yayehrad, Tel +251912960525, Email ashutewabe@gmail.comAbstract: The percentages of organisms exhibiting antimicrobial resistance, especially resistance to multiple antibiotics, are incessantly increasing. Studies investigated that many bacteria are being resistant to ciprofloxacin. This review addresses the current knowledge on nano-based ciprofloxacin delivery approaches to improve its effectiveness and overcome the resistance issues. Ciprofloxacin delivery can be modified by encapsulating with or incorporating in different polymeric nanoparticles such as chitosan, PLGA, albumin, arginine, and other organic and inorganic nanostructure systems. Most of these nano-approaches are promising as an alternative strategy to improve the therapeutic effectiveness of ciprofloxacin in the future.Keywords: antimicrobial resistance, ciprofloxacin, ciprofloxacin resistance, nanotechnology

Simple Summary: In this study, the origin and persistence of Campylobacter jejuni was studied in dairy cattle farms in order to avoid recirculation of this leading cause of foodborne illness. A high level of genetic diversity and antimicrobial resistance was found, particularly in ciprofloxacin. As a result, the survival of antimicrobial resistant C. jejuni in cattle manure may pose a risk for human populations. The aim of this study was the examination of the genetic diversity and antimicrobial susceptibility of C. jejuni isolates obtained from dairy farms situated in Cantabria. The presence of Campylobacter jejuni was scrutinized in dairy farms situated in the Cantabria region (Atlantic coast, North of Spain). A total of 520 samples were collected from 12 dairy farms and 62 C. jejuni isolates were achieved. Sixty-one (61) of the isolates proceeded from fresh feces and only one from the stable (soil). Characterization of the isolates was conducted by Pulsed Field Gel Electrophoresis (PFGE) analysis. Antimicrobial susceptibility testing was carried out by standardized disk diffusion test. The PFGE analysis showed a high genetic diversity. From the 62 C. jejuni isolates, 27 different PFGE types were obtained with 70% similarity. The results of the antimicrobial susceptibility tests showed that 21 out of 27 strains were resistant to ciprofloxacin (78%), and 15 of them were also resistant to tetracycline (55%), whereas none of the 27 strains analyzed were resistant to erythromycin. C. jejuni was capable of surviving in livestock waste for at least 20–25 days, whereas the maximum detectable survival time on crops was of six days. This study reveals the high genetic diversity and ciprofloxacin resistance of C. jejuni in dairy cattle farms in Northern Spain, a fact that highlights the urgent need for the surveillance and control of this foodborne pathogen. [ABSTRACT FROM AUTHOR]

Salmonella enterica serovar Typhi spreads typhoid infection in humans through the consumption of contaminated food and water. Poor sanitation plays a pivotal role in its dissemination. Over time, the bacterium has acquired resistance to many promising antibiotics, posing a growing global health concern and hindering the achievement of sustainable development goals. This study aims to elucidate the molecular complexity of fluoroquinolone resistance, a first-line treatment for typhoid infection. To achieve this aim, 80 clinical isolates were collected from various diagnostic laboratories. These isolates were confirmed based on morphological characteristics and biochemical tests. Multidrug-resistant (MDR) and extensively drug-resistant (XDR) isolates were identified using the Kirby-Bauer disc diffusion method. The mechanism of ciprofloxacin resistance was investigated by sequencing the quinolone resistance-determining region (QRDR) genes and identifying the presence of the qnrS1 gene. As a result of this study, 60 % of isolates showed resistance to ciprofloxacin. At the same time, the qnrS1 gene was present in all the selected strains while mutation analysis identified significant mutation in QRDR of DNA gyrase subunit A (gyrA ) and Topoisomerase IV ( parC ) gene. The combinatorial effect was further investigated by downloading 286 draft genomes. The Mutation analysis reveals significant mutations at gyrA S83F , gyrA D87N , gyrA S83Y , gyrB S464F , parC S80I , and parE L416F. Additionally, docking analysis indicates reduced binding affinity and altered solvent accessibility, which show the structural changes at mutation sites. This study provides crucial insights that mutation reduces the binding affinity while qnrS1 acts as a transport channel to extrude the ciprofloxacin. In the future, further validation through experimental mutagenesis is recommended, for targeted therapeutic interventions against the mounting threat of antibiotic-resistant S. Typhi., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Noman Khan reports financial support and article publishing charges were provided by 10.13039/501100002383King Saud University. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

Ciprofloxacin-resistant Salmonella Typhimurium ( S. Typhimurium) causes a significant health burden worldwide. A wealth of studies has been published on the contributions of different mechanisms to ciprofloxacin resistance in Salmonella spp. But we still lack a deep understanding of the physiological responses and genetic changes that underlie ciprofloxacin exposure. This study aims to know how phenotypic and genotypic characteristics are impacted by ciprofloxacin exposure, from ciprofloxacin-susceptible to ciprofloxacin-resistant strains in vitro . Here, we investigated the multistep evolution of resistance in replicate populations of S. Typhimurium during 24 days of continuously increasing ciprofloxacin exposure and assessed how ciprofloxacin impacts physiology and genetics. Numerous studies have demonstrated that RamA is a global transcriptional regulator that prominently perturbs the transcriptional landscape of S. Typhimurium, resulting in a ciprofloxacin-resistant phenotype appearing first; the quinolone resistance-determining region mutation site can only be detected later. Comparing the microbial physiological changes and RNA sequencing (RNA-Seq) results of ancestral and selectable mutant strains, the selectable mutant strains had some fitness costs, such as decreased virulence, an increase of biofilm-forming ability, a change of "collateral" sensitivity to other drugs, and inability to utilize galactitol. Importantly, in the ciprofloxacin induced, RamA directly binds and activates the gatR gene responsible for the utilization of galactitol, but RamA deletion strains could not activate gatR . The elevated levels of RamA, which inhibit the galactitol metabolic pathway through the activation of gatR , can lead to a reduction in the growth rate, adhesion, and colonization resistance of S . Typhimurium. This finding is supported by studies conducted in M9 medium as well as in vivo infection models., Importance: Treatment of antibiotic resistance can significantly benefit from a deeper understanding of the interactions between drugs and genetics. The physiological responses and genetic mechanisms in antibiotic-exposed bacteria are not well understood. Traditional resistance studies, often retrospective, fail to capture the entire resistance development process and typically exhibit unpredictable dynamics. To explore how clinical isolates of S. Typhimurium respond to ciprofloxacin, we analyzed their adaptive responses. We found that S. Typhimurium RamA-mediated regulation disrupts microbial metabolism under ciprofloxacin exposure, affecting genes in the galactitol metabolic pathways. This disruption facilitates adaptive responses to drug therapy and enhances the efficiency of intracellular survival. A more comprehensive and integrated understanding of these physiological and genetic changes is crucial for improving treatment outcomes., Competing Interests: The authors declare no conflict of interest.

ABSTRACT Neisseria meningitidis causes a life-threatening invasive meningococcal disease (IMD). Isolates resistant to antibiotics, such as penicillin, ceftriaxone, and ciprofloxacin that are recommended for the treatment of IMD patients and their close contacts have been serious public health concerns globally. However, susceptibility profiles to critically important antibiotics and the genetic characteristics of isolates possessing antibiotic resistance are extremely limited as IMD incidence is low in Japan. We assessed the susceptibility profiles of 87 randomly selected, sterile site-derived N. meningitidis strains isolated from hospitals nationwide, recovered between April 1998 and March 2018 in Japan, to seven antibiotics. As a result, we demonstrated, for the first time, that the isolates remained highly susceptible to ceftriaxone, meropenem, azithromycin, ciprofloxacin, chloramphenicol, and rifampin, but not to penicillin. We then characterized the genetic relatedness of six penicillin- and/or ciprofloxacin-resistant isolates obtained in this study with global 112 genomes using core-genome phylogenetic analysis. These results provide the first evidence that invasive lineages such as a penicillin-resistant serogroup W, sequence type (ST)-11 clonal complex (CC), and a ciprofloxacin-resistant serogroup B/C, ST-4821 CC that is considered as a global threat, have been sporadically identified in Japan. Our findings highlight the need to monitor antibiotic resistance in clinical isolates of N. meningitidis, thereby preventing the spread of antibiotic-resistant invasive lineages and maintaining effective treatment for IMD patients and their close contacts. IMPORTANCE Although antibiotics such as penicillin and ceftriaxone can treat invasive meningococcal disease (IMD), the emergence and spread of antibiotic-resistant Neisseria meningitidis have become a global concern. To provide effective treatment, including chemoprophylaxis to IMD patients and their close contacts, we highlighted the importance of recognizing the antibiotic resistance and genetic features of N. meningitidis isolates.

Klebsiella pneumoniae is one of the most common causes of hospital- and community-acquired pneumoniae. Resistance to the extensively used quinolone antibiotic, such as ciprofloxacin, has increased in Klebsiella pneumoniae , which leads to the increase in the risk of initial antibiotic selection for Klebsiella pneumoniae treatment. Rapid and precise identification of ciprofloxacin-resistant Klebsiella pneumoniae (CIRKP) is essential for clinical therapy. Nowadays, matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) is another approach to discover antibiotic-resistant bacteria due to its shorter inspection time and lower cost than other current methods. Machine learning methods are introduced to assist in discovering significant biomarkers from MALDI-TOF MS data and construct prediction models for rapid antibiotic resistance identification. This study examined 16,997 samples taken from June 2013 to February 2018 as part of a longitudinal investigation done by Change Gung Memorial Hospitals (CGMH) at the Linkou branch. We applied traditional statistical approaches to identify significant biomarkers, and then a comparison was made between high-importance features in machine learning models and statistically selected features. Large-scale data guaranteed the statistical power of selected biomarkers. Besides, clustering analysis analyzed suspicious sub-strains to provide potential information about their influences on antibiotic resistance identification performance. For modeling, to simulate the real antibiotic resistance predicting challenges, we included basic information about patients and the types of specimen carriers into the model construction process and separated the training and testing sets by time. Final performance reached an area under the receiver operating characteristic curve (AUC) of 0.89 for support vector machine (SVM) and extreme gradient boosting (XGB) models. Also, logistic regression and random forest models both achieved AUC around 0.85. In conclusion, models provide sensitive forecasts of CIRKP, which may aid in early antibiotic selection against Klebsiella pneumoniae. The suspicious sub-strains could affect the model performance. Further works could keep on searching for methods to improve both the model accuracy and stability. [ABSTRACT FROM AUTHOR]

Klebsiella pneumoniae is one of the most common causes of hospital- and community-acquired pneumoniae. Resistance to the extensively used quinolone antibiotic, such as ciprofloxacin, has increased in Klebsiella pneumoniae, which leads to the increase in the risk of initial antibiotic selection for Klebsiella pneumoniae treatment. Rapid and precise identification of ciprofloxacin-resistant Klebsiella pneumoniae (CIRKP) is essential for clinical therapy. Nowadays, matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) is another approach to discover antibiotic-resistant bacteria due to its shorter inspection time and lower cost than other current methods. Machine learning methods are introduced to assist in discovering significant biomarkers from MALDI-TOF MS data and construct prediction models for rapid antibiotic resistance identification. This study examined 16,997 samples taken from June 2013 to February 2018 as part of a longitudinal investigation done by Change Gung Memorial Hospitals (CGMH) at the Linkou branch. We applied traditional statistical approaches to identify significant biomarkers, and then a comparison was made between high-importance features in machine learning models and statistically selected features. Large-scale data guaranteed the statistical power of selected biomarkers. Besides, clustering analysis analyzed suspicious sub-strains to provide potential information about their influences on antibiotic resistance identification performance. For modeling, to simulate the real antibiotic resistance predicting challenges, we included basic information about patients and the types of specimen carriers into the model construction process and separated the training and testing sets by time. Final performance reached an area under the receiver operating characteristic curve (AUC) of 0.89 for support vector machine (SVM) and extreme gradient boosting (XGB) models. Also, logistic regression and random forest models both achieved AUC around 0.85. In conclusion, models provide sensitive forecasts of CIRKP, which may aid in early antibiotic selection against Klebsiella pneumoniae. The suspicious sub-strains could affect the model performance. Further works could keep on searching for methods to improve both the model accuracy and stability.

Xuxia Yu,1 Danyang Zhang,2 Qifa Song3 1Department of Hospital Infection, Ningbo City First Hospital, Ningbo, Zhejiang Province, People’s Republic of China; 2Department of Microbiology, Ningbo Municipal Centre for Disease Control and Prevention, Ningbo, Zhejiang Province, People’s Republic of China; 3Central Laboratory, Ningbo City First Hospital, Ningbo, Zhejiang Province, People’s Republic of ChinaCorrespondence: Qifa Song Email qifasong@126.comPurpose: Fluoroquinolone-resistant Shigella is considered a serious public health problem and has been put on the WHO global priority list of antibiotic-resistant bacteria. This study was aimed to investigate the fluoroquinolone resistance in Shigella and its relevant genetic mechanisms.Materials and Methods: Shigella isolates that were isolated from diarrheal patient’s feces in Ningbo China from 2011 to 2018 were tested for susceptibility to ampicillin, gentamicin, tetracycline, nalidixic acid, ciprofloxacin, and cefotaxime. Genes related to quinolone resistance were amplified by PCR.Results: A total of 118 Shigella isolates were collected, including 76 S. flexneri isolates, 40 S. sonnei isolates, and 2 S. boydii isolates. Ciprofloxacin susceptibility test identified 10 (9%) susceptible, 65 (55%) intermediate, and 43 (36%) resistant isolates. Of 76 S. flexneri isolates, 37 were ciprofloxacin resistant, a prevalence significantly higher than 6 of 40 S. sonnei isolates (P=0.01). The isolates collected during 2014– 2018 displayed a significant increase in the prevalence of ciprofloxacin resistance (P=0.05) than those collected during 2011– 2013. All the ciprofloxacin-intermediate and resistant isolates had mutations of gyrA(S83L) and parC (S80I), whereas only the ciprofloxacin-resistant isolates had gyrA (D87N) mutation and qnrB gene. Additionally, 30% of the ciprofloxacin-resistant isolates were positive for aac(6´)-Ib-cr gene.Conclusion: This study shows the currently increasing prevalence of ciprofloxacin resistance. The reduced fluoroquinolone susceptibility is highly associated with gyrA (S83L) and parC (S80I) mutations, while the fluoroquinolone resistance is highly associated with gyrA (D87N) mutation, qnrB gene and perhaps aac(6´)-Ib-cr gene.Keywords: Shigella, ciprofloxacin resistance, gyrA mutations, plasmid-mediated quinolone resistance, PMQR, quinolone resistance-determining region, QRDR

Noura E Esmaeel, 1 Marian A Gerges, 1 Thoraya A Hosny, 2 Ahmed R Ali, 3 Manar G Gebriel 1 1Medical Microbiology and Immunology Department, Faculty of Medicine, Zagazig University, Zagazig, Egypt; 2Clinical Pathology Department, Faculty of Medicine, Zagazig University, Zagazig, Egypt; 3Urology Department, Faculty of Medicine, Zagazig University, Zagazig, EgyptCorrespondence: Marian A GergesMedical Microbiology and Immunology Department, Faculty of Medicine, Zagazig University, 44519, EgyptTel +20 1003819530Email maromicro2006@yahoo.comIntroduction: Resistance to fluoroquinolones (FQ) in uropathogenic Escherichia coli (UPEC) has emerged as a growing problem. Chromosomal mutations and plasmid-mediated quinolone resistance (PMQR) determinants have been implicated. Data concerning the prevalence of these determinants in UPEC in our hospital are quite limited.Purpose: To investigate the occurrence and genetic determinants of FQ resistance in UPEC isolated from urinary tract infection (UTI) cases in Zagazig University Hospitals.Patients and Methods: Following their isolation, the identification and susceptibility of UPEC isolates were performed by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometer (MALDI-TOF MS). FQ resistance was detected by the disc diffusion method. Ciprofloxacin minimal inhibitory concentration (MIC) was determined using E-test. Chromosomal mutations in the gyrA gene were detected using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), and for detection of PMQR, a couple of multiplex PCR reactions were used.Results: Among a total of 192 UPEC isolates, 46.9% (n=90) were FQ resistant. More than half of the isolates (57.8%) exhibited high-level ciprofloxacin resistance (MIC > 32 μg/mL). Mutations in gyrA were detected in 76.7% of isolates, with 34.4% having mutations at more than one site. PMQR determinants were detected in 80.1% of UPEC isolates, with aac(6ʹ)-Ib-cr gene being the most frequent found in 61.1% of isolates.Conclusion: There is a high prevalence of both gyrA mutations and PMQR determinants among UPEC isolates in our hospital which contribute to high-level ciprofloxacin resistance, a finding that may require the revision of the antibiotics used for empirical treatment of UTI.Keywords: gyrA mutations, qnr determinants, uropathogenic E. coli, ciprofloxacin resistance

Pseudomonas aeruginosa is a ubiquitous pathogen that causes a wide range of acute and chronic infections. Ciprofloxacin, one of the first-line fluoroquinolone class antibiotics, is commonly used for the treatment of P. aeruginosa infections. However, ciprofloxacin-resistant P. aeruginosa is increasingly reported worldwide, making treatment difficult. To determine resistance-related mutations, we conducted an experimental evolution using a previously identified ciprofloxacin-resistant P. aeruginosa clinical isolate, CRP42. The evolved mutants could tolerate a 512-fold higher concentration of ciprofloxacin than CRP42. Genomic DNA reference mapping was performed, which revealed mutations in genes known to be associated with ciprofloxacin resistance as well as in those not previously linked to ciprofloxacin resistance, including the ParER586W substitution and PA0625 frameshift insertion. Simulation of the ParER586W substitution and PA0625 frameshift insertion by gene editing in CRP42 and the model strain PAO1 demonstrated that while the PA0625 mutation does contribute to resistance, mutation in the ParER586W does not contribute to resistance but rather affects tolerance against ciprofloxacin. These findings advance our understanding of ciprofloxacin resistance in P. aeruginosa.

ABSTRACT Misuse and overuse of antibiotics drive the selection and spread of antibiotic-resistant bacteria. Although genetic mutations have been well defined for different types of antibiotic resistance, ways to revert antibiotic resistance are largely unexplored. Here, we adopted a proteomics approach to investigate the mechanism underlying ciprofloxacin resistance in Edwardsiella tarda, a representative pathogen that infects both economic animal species and human beings. By comparing the protein expression profiles of ciprofloxacin-sensitive and -resistant E. tarda, a total of 233 proteins of differential abundance were identified, where 53 proteins belong to the functional categories of metabolism, featuring a disrupted pyruvate cycle and decreased energy metabolism but increased fatty acid biosynthesis. The altered pyruvate cycle and energy metabolism were confirmed by gene expression and biochemical assays. Furthermore, the role of fatty acid biosynthesis and quinolone resistance were explored. The expression level and enzymatic activity of acetyl coenzyme A (acetyl-CoA) carboxylase, the first step of fatty acid biosynthesis, were increased in ciprofloxacin-resistant E. tarda. Treatment of ciprofloxacin-resistant E. tarda with acetyl-CoA carboxylase and 3-oxoacyl-[acyl carrier protein] synthase II inhibitors, 2-aminooxazole and triclosan, respectively, reduced the expression of fatty acid biosynthesis and promoted quinolone-mediated killing efficacy to antibiotic-resistant bacteria. Similar results were obtained in clinically isolated E. tarda strains. Our study suggests that energy metabolism has been reprogramed in ciprofloxacin-resistant bacteria that favor the biosynthesis of fatty acid, presenting a novel target to tackle antibiotic-resistant bacteria. IMPORTANCE Edwardsiella tarda is the causative agent of edwardsiellosis, which imposes huge challenges on clinics and aquaculture. Due to the overuse of antibiotics, the emergence and spread of antibiotic-resistant E. tarda threaten human health and animal farming. However, the mechanism of ciprofloxacin resistance in E. tarda is still lacking. Here, iTRAQ (isobaric tags for relative and absolute quantification)-based proteomics was performed to identify a differential proteome between ciprofloxacin-sensitive and -resistant E. tarda. The fluctuated pyruvate cycle and reduced energy metabolism and elevated fatty acid biosynthesis are metabolic signatures of ciprofloxacin resistance. Moreover, inhibition of biosynthesis of fatty acids promotes quinolone-mediated killing efficacy in both lab-evolved and clinically isolated strains. This study reveals that a ciprofloxacin resistance mechanism is mediated by the elevated biosynthesis of fatty acids and the depressed pyruvate metabolism and energy metabolism in E. tarda. These findings provide a novel understanding for the ciprofloxacin resistance mechanism in E. tarda.

Campylobacter jejuni is the leading cause of bacterial gastroenteritis and antibiotic resistant C. jejuni are a serious threat to public health. Herein, we sought to evaluate trends in C. jejuni infections, quantify resistance frequencies, and identify epidemiological factors associated with infection. Campylobacter jejuni isolates (n = 214) were collected from patients via an active surveillance system at four metropolitan hospitals in Michigan between 2011 and 2014. The minimum inhibitory concentration for nine antibiotics was determined using microbroth dilution, while demographic and clinical data were used for the univariate and multivariate analyses. Over the 4-year period, a significant increase in the recovery of C. jejuni was observed (p ≤ 0.0001). Differences in infection rates were observed by hospital and several factors were linked to more severe disease. Patients residing in urban areas, for instance, were significantly more likely to be hospitalized than rural residents as were patients over 40 years of age and those self-identifying as non-White, highlighting potential disparities in disease outcomes. Among the 214 C. jejuni isolates, 135 (63.1%) were resistant to at least one antibiotic. Resistance was observed for all nine antibiotics tested yielding 11 distinct resistance phenotypes. Tetracycline resistance predominated (n = 120; 56.1%) followed by resistance to ciprofloxacin (n = 49; 22.9%), which increased from 15.6% in 2011 to 25.0% in 2014. Resistance to two antibiotic classes was observed in 38 (17.8%) isolates, while multidrug resistance, or resistance to three or more classes, was observed in four (1.9%). Notably, patients with ciprofloxacin resistant infections were more likely to report traveling in the past month (Odds Ratio (OR): 3.0; 95% confidence interval (CI): 1.37, 6.68) and international travel (OR: 9.8; 95% CI: 3.69, 26.09). Relative to patients with only tetracycline resistant infections, those with ciprofloxacin resistance were more likely to travel internationally, be hospitalized and have an infection during the fall or summer. Together, these findings show increasing rates of infection and resistance and highlight specific factors that impact both outcomes. Enhancing understanding of factors linked to C. jejuni resistance and more severe infections is critical for disease prevention, particularly since many clinical laboratories have switched to the use of culture-independent tests for the detection of Campylobacter.

BACKGROUND: Enteric fever is the most common cause of community acquired blood stream infections in under developed and developing countries. The enteric fever is exclusive to humans and transmitted through the faeco-oral route. Though India is an endemic zone for enteric fever, the data is very scarce from Central India. The present study was undertaken to determine the prevalence of enteric fever in this region and to know the antimicrobial susceptibility pattern of the isolated typhoidal Salmonellae. MATERIAL AND METHOD: We conducted a retrospective analysis of blood culture positive cases of enteric fever over a period of two years (December 2015 to December 2017). All blood cultures submitted for suspected enteric fever and associated symptoms were included in the study. Relevant demographic, clinical and laboratory data were analyzed. RESULT: A total of 51 cases (3.56%) were of typhoidal Salmonella from a total of 1430 blood culture submission. Salmonella Typhi were 70.5% while Salmonella Paratyphi A were 29.5% of the total isolated Salmonellae. The most vulnerable age group was 10-19years (41.2%). The mean minimum inhibitory concentration of ciprofloxacin for Salmonella Typhi and Salmonella Paratyphi A are 1.20 and 1.97 μg/ml respectively. All the isolates were susceptible to ceftriaxone. Highest isolation was in the July – September quarter (35.3%). CONCLUSION: There is a high prevalence of the disease which needs urgent focus on safe water, sanitation services and also to establish guidelines for empiric therapy for enteric fever.

Abstract Background Antibiotic-resistant Enterobacteriaceae in the gastrointestinal flora can lead to infections with limited therapeutic options. Also, the resistant bacteria can be transferred from colonized persons to others. The present study was conducted to search the fecal carriage rates of (i) Enterobacteriaceae that produce extended-spectrum β-lactamase (ESBL-E) and/or (ii) plasmid-mediated AmpC β-lactamase (pAmpC-E), (iii) ciprofloxacin-resistant Enterobacteriaceae (CIP-RE), and (iv) carbapenem-intermediate or -resistant Enterobacteriaceae (CIRE) in Northern Cyprus. Methods A total of 500 community-dwellers were recruited from consecutive admissions to the clinical laboratories of four hospitals. One rectal swab or stool sample was collected from each participant. A questionnaire was applied to evaluate possible risk factors associated with intestinal colonization of resistant bacteria. The samples were cultured on antibiotic containing media to screen for resistant bacteria colonization. The bacterial colonies that grew on the plates were subjected to further phenotypic tests to confirm the resistance. Results Of 500 volunteers, ESBL-E, pAmpC-E, CIP-RE and CIRE carriage were detected in 107 (21.4%), 15 (3.0%), 51 (10.2%) and six (1.2%) participants, respectively. Escherichia coli was the most commonly recovered species among Enterobacteriaceae isolates. A significant proportion of ESBL-producing E. coli isolates (n = 22/107; 20.6%) was found to be co-resistant to CIP (p = 0.000, OR 3.21, 95% CI 1.76–5.87). In this study, higher socioeconomic status (CIP-RE: p = 0.024, OR 1.96, 95% CI 1.09–3.53), presence of gastrointestinal symptoms (CIRE: p = 0.033; OR 6.79, 95% CI 1.34–34.39), antibiotic use (ESBL-E: p = 0.031; OR 1.67, 95% CI 1.04–2.67; and CIRE: p = 0.033; OR 6.40, 95% CI 1.16–35.39), and travelling abroad (pAmpC-E: p = 0.010; OR 4.12, 95% CI 1.45–11.66) were indentified as risk factors. Conclusion The study indicates that resistant Enterobacteriaceae isolates are carried by humans in the community. To prevent further spread of resistance, rational use of antibiotics should be encouraged, and antibiotic resistance should be carefully monitored in Northern Cyprus.

Abstract Background Fluoroquinolone resistance and ESBL-production are concurrently found in a limited number of Salmonella serotypes. The present study was aimed to characterize fluoroquinolone-resistant and ESBL-producing Salmonella enteric serotype Derby (S. Derby) isolates in terms of antimicrobial susceptibility, relevant genetic mechanisms, and PFGE. Results From 2013 to 2017 in Ningbo China, 52 S. Derby isolates were identified out of 826 non-typhoidal Salmonella isolates from patient feces, food, and environmental water samples. Three S. derby isolates were identified to be fluoroquinolone-resistant and ESBL-producing with cefotaxime MIC of 64 μg/mL and ciprofloxacin MIC of 4 μg/mL. The three isolates contained the same genetic structure of quinolone resistance, including a silent gyrA mutation S (TCC) 83S (TCT) and three PMQR genes qnrB, qnrS and aac(6′)-Ib-cr. As withβ-lactams resistance mechanisms, two isolates contained bla TEM, bla OXA, and bla CTX-M genes and one isolate contained bla OXA and bla CTX-M genes. Additionally, two isolates displayed more identical PFGE pattern than the third isolate, whereas three isolates showed the same plasmid profile of I1, W and P by PCR-based replicon typing. The conjugation experiment showed no dissemination of β-lactam resistance by direct contact among isolates; the transformation experiment failed to transfer plasmid conferring ampicillin resistance to E. coli DH5a. Conclusion The present study demonstrates the emerging fluoroquinolone-resistant and ESBL-producing S. Derby in both humans and the environment. Seeing that S. Derby has become one of the most common Salmonella serotypes, this situation gives rise to a new major risk of food-borne diseases.

ABSTRACTCeftriaxone and ciprofloxacin are the drugs of choice in treatment of invasive Salmonella infections. This study discovered a novel type of plasmid, pSa44-CIP-CRO, which was recovered from a S. London strain isolated from meat product and comprised genetic determinants that encoded resistance to both ciprofloxacin and ceftriaxone. This plasmid could be resolved into two daughter plasmids and co-exist with such daughter plasmids in a dynamic form in Salmonella; yet it was only present as a single plasmid in Escherichia coli. One daughter plasmid, pSa44-CRO, was found to carry the blaCTX-M-130 gene, which encodes resistance to ceftriaxone, whereas the other plasmid, pSa44-CIP, carried multiple PMQR genes such as qnrB6-aac(6’)-Ib-cr, which mediated resistance to ciprofloxacin. These two daughter plasmids could be integrated into one single plasmid through ISPa40 mediated homologous recombination. Mouse infection and treatment experiments showed that carriage of plasmid, pSa44-CIP-CRO by S. typhimurium led to the impairment of treatment by ciprofloxacin or cefitiofur, a veterinary drug with similar properties as ceftriaxone. In conclusion, dissemination of such conjugative plasmids impairs current choices of treatment for life-threatening Salmonella infection and hence constitutes a serious public health threat.

ABSTRACTCiprofloxacin resistance in Salmonella has been increasingly reported due to the emergence and dissemination of multiple Plasmid-Mediated Quinolone Resistance (PMQR) determinants, which are mainly located in non-conjugative plasmids or chromosome. In this study, we aimed to depict the molecular mechanisms underlying the rare phenomenon of horizontal transfer of ciprofloxacin resistance phenotype in Salmonella by conjugation experiments, S1-PFGE and complete plasmid sequencing. Two types of non-conjugative plasmids, namely an IncX1 type carrying a qnrS1 gene, and an IncH1 plasmid carrying the oqxAB-qnrS gene, both ciprofloxacin resistance determinants in Salmonella, were recovered from two Salmonella strains. Importantly, these non-conjugative plasmids could be fused with a novel Incl1 type conjugative helper plasmid, which could target insertion sequence (IS) elements located in the non-conjugative, ciprofloxacin-resistance-encoding plasmid through replicative transcription, eventually forming a hybrid conjugative plasmid transmissible among members of Enterobacteriaceae. Since our data showed that such conjugative helper plasmids are commonly detectable among clinical Salmonella strains, particularly S. Typhimurium, fusion events leading to generation and enhanced dissemination of conjugative ciprofloxacin resistance-encoding plasmids in Salmonella are expected to result in a sharp increase in the incidence of resistance to fluoroquinolone, the key choice for treating life-threatening Salmonella infections, thereby posing a serious public health threat.

Aliarcobacter cibarius and Aliarcobacter thereius are two rarely detected Aliarcobacter species. In the study, we analyzed the antimicrobial susceptibility and provide detailed insights into the genotype and phylogeny of both species using whole-genome sequencing. Thermophilic Campylobacter species are the most common bacterial foodborne pathogens causing gastroenteritis in humans worldwide. The genus Aliarcobacter is part of the Campylobacteraceae family and includes the species Aliarcobacter butzleri, Aliarcobacter cryaerophilus, Aliarcobacter skirrowii, and the rarely described Aliarcobacter cibarius, Aliarcobacter faecis, Aliarcobacter lanthieri, Aliarcobacter thereius, and Acrobarter trophiarum. Aliarcobacter are emergent enteropathogens and potential zoonotic agents. Here, we generated, analyzed, and characterized whole-genome sequences of Aliarcobacter cibarius and Aliarcobacter thereius. They were isolated from water poultry farms in Germany, cultured and identified by MALDI-TOF MS. With PCR the identity was verified. Antibiotic susceptibility testing was carried out with erythromycin, ciprofloxacin, doxycycline, tetracycline, gentamicin, streptomycin, ampicillin, and cefotaxime using the gradient strip method (E-test). Whole-genome sequences were generated including those of reference strains. Complete genomes for six selected strains are reported. These provide detailed insights into the genotype. With these, we predicted in silico known AMR genes, virulence-associated genes, and plasmid replicons. Phenotypic analysis of resistance showed differences between the presence of resistance genes and the prediction of phenotypic resistance profiles. In Aliarcobacter butzleri, the nucleotide sequence of the gyrA gene (DQ464331) can show a signature mutation resulting in an amino acid change T85>I. Acrobarter cibarius and Acrobarter thereius showed the same gene as assessed by similarity annotation of the mutations 254C>G. Most of the isolates were found to be sensitive to ciprofloxacin. The ciprofloxacin-resistant Aliarcobacter thereius isolate was associated with the amino acid change T85>I. But this was not predicted with antibiotic resistance databases, before. Ultimately, a phylogenetic analysis was done to facilitate in future outbreak analysis.

Aliarcobacter cibarius and Aliarcobacter thereius are two rarely detected Aliarcobacter species. In the study, we analyzed the antimicrobial susceptibility and provide detailed insights into the genotype and phylogeny of both species using whole-genome sequencing. Thermophilic Campylobacter species are the most common bacterial foodborne pathogens causing gastroenteritis in humans worldwide. The genus Aliarcobacter is part of the Campylobacteraceae family and includes the species Aliarcobacter butzleri, Aliarcobacter cryaerophilus, Aliarcobacter skirrowii , and the rarely described Aliarcobacter cibarius, Aliarcobacter faecis, Aliarcobacter lanthieri, Aliarcobacter thereius , and Acrobarter trophiarum. Aliarcobacter are emergent enteropathogens and potential zoonotic agents. Here, we generated, analyzed, and characterized whole-genome sequences of Aliarcobacter cibarius and Aliarcobacter thereius. They were isolated from water poultry farms in Germany, cultured and identified by MALDI-TOF MS. With PCR the identity was verified. Antibiotic susceptibility testing was carried out with erythromycin, ciprofloxacin, doxycycline, tetracycline, gentamicin, streptomycin, ampicillin, and cefotaxime using the gradient strip method (E-test). Whole-genome sequences were generated including those of reference strains. Complete genomes for six selected strains are reported. These provide detailed insights into the genotype. With these, we predicted in silico known AMR genes, virulence-associated genes, and plasmid replicons. Phenotypic analysis of resistance showed differences between the presence of resistance genes and the prediction of phenotypic resistance profiles. In Aliarcobacter butzleri , the nucleotide sequence of the gyr A gene (DQ464331) can show a signature mutation resulting in an amino acid change T85>I. Acrobarter cibarius and Acrobarter thereius showed the same gene as assessed by similarity annotation of the mutations 254C>G. Most of the isolates were found to be sensitive to ciprofloxacin. The ciprofloxacin-resistant Aliarcobacter thereius isolate was associated with the amino acid change T85>I. But this was not predicted with antibiotic resistance databases, before. Ultimately, a phylogenetic analysis was done to facilitate in future outbreak analysis. [ABSTRACT FROM AUTHOR]

Treatment of infections by Pseudomonas aeruginosa is difficult due to its high intrinsic and acquired antibiotic resistance. Upon colonization in the human hosts, P. aeruginosa accumulates genetic mutations that confer the bacterium antibiotic resistance and ability to better live in the host environment. Characterizing the evolutionary traits would provide important insights into the development of effective combinatory antibiotic therapies to cure P. aeruginosa infections. In this work, we performed a detailed analysis of the molecular mechanisms by which a clinical isolate (CSP18) yields a ciprofloxacin-resistant derivative (CRP42). Genomic DNA re-sequencing and RNAseq were carried out to compare the genomic mutational signature and transcriptional profiles between the two isolates. The results indicated that D87G mutation in GyrA, together with MexEF-OprN hyper-expression caused by F7S mutation in MexS, was responsible for the increased resistance to ciprofloxacin in the isolate CRP42. Further simulation of CRP42 by gene editing in CSP18 demonstrated that D87G mutation in GyrA rendered CSP18 a fourfold increase in minimum inhibitory concentration against ciprofloxacin, while F7S mutation in MexS conferred an additional eightfold increase. Our experimental results demonstrate for the first time that the clinically relevant F7S point mutation in MexS results in hyper-expression of the mexEF-oprN and thus confers P. aeruginosa resistance to ciprofloxacin.

ABSTRACT The incidence of ciprofloxacin resistance in Salmonella has increased dramatically in the past decade. To track the evolutionary trend of ciprofloxacin resistance-encoding genetic elements during this period, we surveyed the prevalence of Salmonella in food products in Shenzhen, China, during the period of 2012 to 2017 and performed whole-genome sequencing and genetic analysis of 566 ciprofloxacin-resistant clinical Salmonella strains collected during this survey. We observed that target gene mutations have become much less common, with single gyrA mutation currently detectable in Salmonella enterica serovar Typhimurium only. Multiple plasmid-mediated quinolone resistance (PMQR) genes located in the chromosome and plasmids are now frequently detectable in ciprofloxacin-resistant Salmonella strains of various serotypes. Among them, the qnrS1 gene was often harbored by multiple plasmids, with p10k-like plasmids being the most dominant. Importantly, p10k-like plasmids initially were not conjugative but became transmissible with the help of a helper plasmid. Ciprofloxacin resistance due to combined effect of carriage of the qnrS1 gene and other resistance mechanisms is common. In S. Typhimurium, carriage of qnrS1 is often associated with a single gyrA mutation; in other serotypes, combination of qnrS1 and other PMQR genes located in the chromosomal fragment or plasmid is observed. Another major mechanism of ciprofloxacin resistance, mainly observable in S. Derby, involves a chromosomal fragment harboring the qnrS2–aac(6′)lb-cr–oqxAB elements. Intriguingly, this chromosomal fragment, flanked by IS26, could form a circular intermediate and became transferrable. To conclude, the increase in the incidence of various PMQR mobile genetic elements and their interactions with other resistance mechanism contribute to a sharp increase in the prevalence of ciprofloxacin-resistant clinical Salmonella strains in recent years. IMPORTANCE Resistance of nontyphoidal Salmonella to fluoroquinolones such as ciprofloxacin is known to be mediated by target mutations. This study surveyed the prevalence of Salmonella strains recovered from 2,989 food products in Shenzhen, China, during the period 2012 to 2017 and characterized the genetic features of several PMQR gene-bearing plasmids and ciprofloxacin resistance-encoding DNA fragments. The emergence of such genetic elements has caused a shift in the genetic location of ciprofloxacin resistance determinants from the chromosomal mutations to various mobile genetic elements. The distribution of these PMQR plasmids showed that they exhibited high serotype specificity, except for the p10k-like plasmids, which can be widely detected and efficiently transmitted among Salmonella strains of various serotypes by fusing to a new conjugative helper plasmid. The sharp increase in the prevalence of ciprofloxacin resistance in recent years may cause a predisposition to the emergence of multidrug-resistant Salmonella strains and pose huge challenges to public health and infection control efforts.

Treatment of infections by Pseudomonas aeruginosa is difficult due to its high intrinsic and acquired antibiotic resistance. Upon colonization in the human hosts, P. aeruginosa accumulates genetic mutations that confer the bacterium antibiotic resistance and ability to better live in the host environment. Characterizing the evolutionary traits would provide important insights into the development of effective combinatory antibiotic therapies to cure P. aeruginosa infections. In this work, we performed a detailed analysis of the molecular mechanisms by which a clinical isolate (CSP18) yields a ciprofloxacin-resistant derivative (CRP42). Genomic DNA re-sequencing and RNAseq were carried out to compare the genomic mutational signature and transcriptional profiles between the two isolates. The results indicated that D87G mutation in GyrA, together with MexEF-OprN hyper-expression caused by F7S mutation in MexS, was responsible for the increased resistance to ciprofloxacin in the isolate CRP42. Further simulation of CRP42 by gene editing in CSP18 demonstrated that D87G mutation in GyrA rendered CSP18 a fourfold increase in minimum inhibitory concentration against ciprofloxacin, while F7S mutation in MexS conferred an additional eightfold increase. Our experimental results demonstrate for the first time that the clinically relevant F7S point mutation in MexS results in hyper-expression of the mexEF-oprN and thus confers P. aeruginosa resistance to ciprofloxacin. [ABSTRACT FROM AUTHOR]

A local outbreak caused by Neisseria meningitidis occurred in the migration camp in the Greek island of Lesbos during January–February 2020 (4 of 5 cases). In total, 5 samples positive for N. meningitidis were further investigated for sero-/genogroup, PorA, and WGS analysis. MenB was found among 3 cases, while in two cases, MenY was identified. WGS analysis and antibiotic susceptibility testing on the 2 culture positive MenB samples showed the new ST-3129, ciprofloxacin-resistant clone was circulating among the immigrants in the aforementioned camp. This is the first report of ciprofloxacin resistance in Greece. [ABSTRACT FROM AUTHOR]

Background: Multidrug-resistant uropathogens are becoming widespread both in community and hospital setting. Safe yet effective treatments are a priority. Fosfomycin is an antibacterial that displays good activity against most bacteria causing urinary tract infections (UTIs), including multidrug-resistant bacteria. The aim of this study was to evaluate fosfomycin susceptibility for uropathogens isolated from a microbiology laboratory at a tertiary academic hospital. In addition, this was compared to the susceptibility of other oral antimicrobials. Methods: We conducted a retrospective analysis of laboratory reports for uropathogens isolated at Charlotte Maxeke Johannesburg Academic Hospital from September 2015 to August 2017. Antimicrobial susceptibility testing of the isolates was performed using the Kirby–Bauer disk diffusion method or the Vitek® 2 system according to the Clinical and Laboratory Standards Institute. Results: Overall susceptibility of fosfomycin for the 4700 Enterobacteriaceae isolates was 95.7%; 95% confidence interval (CI) 95.1–96.2. The overall susceptibility for fosfomycin against the gram-positives was 98.6%. There were 37.9% multidrug-resistant Enterobacteriaceae (MDRE) isolated during the study period. Fosfomycin displayed activity against 94.4% of extended-spectrum β-lactamase (ESBL) producers and 90.7% for carbapenem-resistant Enterobacteriaceae (CRE). None of the methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus isolates tested was fosfomycin resistant. The overall in vitro susceptibility was significantly higher for fosfomycin (p = 0.0001) compared to amoxicillin/clavulanic acid, cephalexin, cefuroxime, ciprofloxacin, trimethoprim/sulfamethoxazole and nitrofurantoin. Conclusion: This study confirmed the high susceptibility of fosfomycin against UTI pathogens isolated at our institution. In an era of increasing antimicrobial resistance, fosfomycin represents a potential option for the treatment of UTIs at Charlotte Maxeke Johannesburg Academic Hospital.

Resistance to ciprofloxacin, a treatment choice for Salmonella infections, has increased dramatically in recent years in particular in serotype Salmonella Derby with most of strains carrying chromosome-encoded multiple plasmid-mediated quinolone resistance (PMQR) genes. In this work, we discovered a conjugative plasmid, pSa64-96kb, in a Salmonella Derby isolate, namely Sa64, which could extract and fuse to a multiple drug resistance (MDR) DNA fragment containing two PMQR genes, aac(6’)-Ib-cr, and qnrS2 located on the chromosome of the Salmonella strain. This process led to the formation of a new 188 kb fusion plasmid, which could be then subsequently transmitted to recipient strain Escherichia coli J53. The chromosomal MDR DNA fragment was shown to be flanked by one copy of IS26 element at each end and could be excised from the chromosome to form circular intermediate, which was then fused to pSa64-96kb and form a single plasmid through IS26 mediated homologous recombination. The role of IS26 on enhancing the efficacy of fusion and transmission of this chromosomal MDR DNA fragment was further proven in other Salmonella strains. These findings showed that dynamic interaction between specific chromosomal fragment and plasmids may significantly enhance resistance development and transferability of mobile resistance-encoding elements among bacterial pathogens.

Introduction: Invasive meningococcal disease (IMD) caused by non-serogroupable (NG) strains mainly affects immunocompromised individuals. Reduced susceptibility to penicillin in meningococci is increasing in Europe but ciprofloxacin resistance remains rare. In 2019, three travel-related meningococcal disease cases caused by a ciprofloxacin-resistant NG strain were identified in England, leading Germany to report four additional IMD cases (2016 to 2019). We describe these and newly identified cases and characterise the strain responsible.Methods: Cases were identified as part of national surveillance and by analysing available genomes using PubMLST tools.Results: Of the cases identified in England in 2019, two geographically distinct cases developed conjunctivitis after returning from Mecca (Kingdom of Saudi Arabia) and a third linked case presented with IMD. Of the four cases from Germany, three occurred in asylum seekers - two familial and a further geographically distinct case. Further IMD cases were identified in Italy (n = 2; 2017-2018), Sweden (n = 1; 2016) and England (n = 1; 2015). A single ST-175 clonal complex (cc175) strain with genosubtype P1.22-11,15-25 was responsible. Decreased susceptibility to penicillin was widespread with three ciprofloxacin resistant subclusters. Constituent isolates were potentially covered by subcapsular vaccines.Conclusion: This disease associated NG cc175 strain exhibits resistance to antibiotics commonly used to prevent IMD but is potentially covered by subcapsular (meningococcal B) vaccines. [ABSTRACT FROM AUTHOR]

Resistance to ciprofloxacin, a treatment choice for Salmonella infections, has increased dramatically in recent years in particular in serotype Salmonella Derby with most of strains carrying chromosome-encoded multiple plasmid-mediated quinolone resistance (PMQR) genes. In this work, we discovered a conjugative plasmid, pSa64-96kb, in a Salmonella Derby isolate, namely Sa64, which could extract and fuse to a multiple drug resistance (MDR) DNA fragment containing two PMQR genes, aac(6')-Ib-cr , and qnrS2 located on the chromosome of the Salmonella strain. This process led to the formation of a new 188 kb fusion plasmid, which could be then subsequently transmitted to recipient strain Escherichia coli J53. The chromosomal MDR DNA fragment was shown to be flanked by one copy of IS 26 element at each end and could be excised from the chromosome to form circular intermediate, which was then fused to pSa64-96kb and form a single plasmid through IS 26 mediated homologous recombination. The role of IS 26 on enhancing the efficacy of fusion and transmission of this chromosomal MDR DNA fragment was further proven in other Salmonella strains. These findings showed that dynamic interaction between specific chromosomal fragment and plasmids may significantly enhance resistance development and transferability of mobile resistance-encoding elements among bacterial pathogens. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to highlight the importance of mutations within Proteus mirabilis genome that are related to fluoroquinolone resistance. Methods: This is a cross sectional study performed in different teaching hospitals in Khartoum State from June 2016 to May 2017. A total of (120) P mirabilis isolates from patients with symptoms of UTIs attending different hospitals in Khartoum State were examined. First, modified Kurby Bauer method was performed for phenotypical detection of resistant isolates. Then polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) followed by sequencing were applied for detection of mutations in GyrA, GyrB, ParC and ParE genes of isolates. Results: P. mirabilis showed 30% resistance to ciprofloxacin. All samples revealed mutation at (serine 83) of GyrA and (serine 84) of ParC by Hinf1 restriction endonuclease digestion. Sequencing was performed for 12 samples. For each gene, two resistant and one susceptible strains were randomly selected. The mutations associated with ciprofloxacin resistant P. mirabilis were as follows; (1/3) GyrA (Ser 83 to Ile) and (2/3) ParC (Ser 81 to Ile). Also it revealed silent mutations at codons of GyrB 474 leucine (3/3), 585 valine (2/3), 612 histidine (1/3) and 639 asparagine (1/3) and ParE 469 isoleucine (2/3), 531 aspartic (2/3) and 533 glycine (1/3). Conclusions: Ciprofloxacin resistance in P. mirabilis could be monitored through detection of mutations within DNA gyrase (encoded by gyrA and gyrB) and topoisomerase IV (encoded by parC and parE). [ABSTRACT FROM AUTHOR]

Introduction: The emergence of fluoroquinolone resistant Salmonella has become a serious public health concern. The antimicrobials of plant origin are considered as alternatives to synthetic drugs. Mango seed kernel has been used in Indian systems of medicine, Ayurveda for many years. Hence, this study was aimed to assess the antibacterial efficacy of the methanol extract of mango seed kernel against ciprofloxacin resistant and ciprofloxacin susceptible Salmonella Typhi isolates. Materials and Methods: The methanol extract of mango seed kernel was prepared by cold percolation method. S. Typhi (n = 48) isolated from the blood culture of patients with enteric fever were included in the study. Minimum inhibitory concentration (MIC) of the methanol extract of mango kernel and the standard antibiotic ciprofloxacin was assessed by broth microdilution method. Results: Of 48 clinical isolates of S. Typhi, 24 (50%) were intermediately susceptible to ciprofloxacin (MIC range: 0.24-0.5 μg/mL) while, 24 (50%) were resistant to ciprofloxacin (MIC range: 1 to >4 mg/mL). The methanolic extract of mango seed kernel displayed significant anti-salmonella activity. MIC50 and MIC90 of the methanolic extract of mango kernel was found to be >16 mg/mL. Conclusion: Among the 24 ciprofloxacin resistant isolates, 1 (4.2%), 5 (20.8%), and 1 (4.2%) isolates had mango seed kernel MIC of 8, 12, and 16 mg/mL, respectively. Of the 13 isolates with a higher ciprofloxacin MIC (>4 μg/mL), 5 (38.5%) were inhibited at a concentration of ≤12 mg/mL of methanol extract of mango kernel. Our results suggest mango kernel seed extract would serve as a better alternative for the effective treatment of invasive Salmonella infections. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate ciprofloxacin resistance (CR) and extended-spectrum beta-lactamase (ESBL) positivity in the rectal flora, antibiotic prophylaxis received, and post-biopsy infectious complications in patients undergoing prostate biopsy.Material& Methods: Rectal swab samples collected from 99 patients suspected of prostate cancer two days before prostate biopsy were tested for microbial susceptibility and ESBL production. All patients were given standard ciprofloxacin and ornidazole prophylaxis. Ten days post-biopsy, the patients were contacted by phone and asked about the presence of fever and/or symptoms of urinary tract infection.Results: Escherichia coli (E.coli) was the most common isolate detected in 82 (75%) of the rectal swab samples. Ciprofloxacin resistance was detected in 33% and ESBL positivity in 22% of the isolated E.coli strains. No microorganisms other than E.coli were detected in blood, urine, and rectal swab cultures of patients who developed post-biopsy complications. CR E.coli strains also showed resistance to other antimicrobial agents. The lowest resistance rates were to amikacin (n = 2, 7.4%) and nitrofurantoin (n = 1, 3.7%). Seven patients (7.6%) developed infectious complications. There was no significant difference in probability of hospitalization between patients with CR strains (14.3%) and those with ciprofloxacin-susceptible strains (14.3% vs. 4.7%; p = 0.194). However, strains that were both CR and ESBL-positive were associated with significantly higher probability of hospitalization compared to ciprofloxacin-susceptible strains (28.6% vs. 3.8%; p = 0.009).Conclusion: The higher rate of infectious complications with CR and ESBL-positive strains suggests that the agents used for antibiotic prophylaxis should be reevaluated. It is important to consider local resistance data when using extended-spectrum agents to treat patients presenting with post-biopsy infectious complications. [ABSTRACT FROM AUTHOR]

Background: Multidrug-resistant uropathogens are becoming widespread both in community and hospital setting. Safe yet effective treatments are a priority. Fosfomycin is an antibacterial that displays good activity against most bacteria causing urinary tract infections (UTIs), including multidrug-resistant bacteria. The aim of this study was to evaluate fosfomycin susceptibility for uropathogens isolated from a microbiology laboratory at a tertiary academic hospital. In addition, this was compared to the susceptibility of other oral antimicrobials. Methods: We conducted a retrospective analysis of laboratory reports for uropathogens isolated at Charlotte Maxeke Johannesburg Academic Hospital from September 2015 to August 2017. Antimicrobial susceptibility testing of the isolates was performed using the Kirby-Bauer disk diffusion method or the Vitek® 2 system according to the Clinical and Laboratory Standards Institute. Results: Overall susceptibility of fosfomycin for the 4700 Enterobacteriaceae isolates was 95.7%; 95% confidence interval (CI) 95.1-96.2. The overall susceptibility for fosfomycin against the gram-positives was 98.6%. There were 37.9% multidrug-resistant Enterobacteriaceae (MDRE) isolated during the study period. Fosfomycin displayed activity against 94.4% of extended-spectrum ß-lactamase (ESBL) producers and 90.7% for carbapenem-resistant Enterobacteriaceae (CRE). None of the methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus isolates tested was fosfomycin resistant. The overall in vitro susceptibility was significantly higher for fosfomycin (p = 0.0001) compared to amoxicillin/clavulanic acid, cephalexin, cefuroxime, ciprofloxacin, trimethoprim/sulfamethoxazole and nitrofurantoin. Conclusion: This study confirmed the high susceptibility of fosfomycin against UTI pathogens isolated at our institution. In an era of increasing antimicrobial resistance, fosfomycin represents a potential option for the treatment of UTIs at Charlotte Maxeke Johannesburg Academic Hospital. [ABSTRACT FROM AUTHOR]

Bacterial non-coding RNAs (ncRNAs) play important regulatory roles in various physiological metabolic pathways. In this study, a novel ncRNA CsiR (ciprofloxacin stress-induced ncRNA) involved in the regulation of ciprofloxacin resistance in the foodborne multidrug-resistant Proteus vulgaris (P. vulgaris) strain P3M was identified. The survival rate of the CsiR-deficient strain was higher than that of the wild-type strain P3M under the ciprofloxacin treatment condition, indicating that CsiR played a negative regulatory role, and its target gene emrB was identified through further target prediction, quantitative real-time PCR (qRT-PCR), and microscale thermophoresis (MST). Further studies showed that the interaction between CsiR and emrB mRNA affected the stability of the latter at the post-transcriptional level to a large degree, and ultimately affected the ciprofloxacin resistance of P3M. Notably, the base-pairing sites between CsiR and emrB mRNAs were highly conserved in other sequenced P. vulgaris strains, suggesting that this regulatory mechanism may be ubiquitous in this species. To the best of our knowledge, this is the first identification of a novel ncRNA involved in the regulation of ciprofloxacin resistance in P. vulgaris species, which lays a solid foundation for comprehensively expounding the antibiotic resistance mechanism of P. vulgaris.

(1) Background: Sexually transmitted infections (STIs) are among the most common infections worldwide, many of these being caused by Neisseria gonorrhoeae (NG). Increased antimicrobial NG resistance has been reported in recent decades, highlighting the need for new sources of natural compounds with valuable antimicrobial activity. This study aims to determine the effect of propolis extracts on NG strains, including antibiotic-resistant strains. (2) Methods: First void urine samples from presumed positive STI subjects were harvested. DNA was extracted, purified, and amplified via PCR for the simultaneous detection of 6 STIs. The presence of the dcmH, gyrA, and parC genes was checked in the DNA samples from NG-positive patients. The antimicrobial activity of 5 aqueous propolis extracts from central Romania was investigated in vitro against some isolated NG strains. ANOVA tests were employed to assess differences and interactions between the inhibition zone for NG strains and propolis extracts. (3) Results: 7.07% of the patients presented NG infections, some strains being resistant or intermediate-resistant to ciprofloxacin. All propolis samples exhibited an antibacterial effect, including on resistant strains. (4) Conclusions: Statistical analysis demonstrated that the diameter of the inhibition zone was influenced both by the NG strain type and the source of the propolis extracts.

Pseudomonas aeruginosa is an opportunistic bacterial pathogen that causes various acute and chronic infections. It is intrinsically resistant to a variety of antibiotics. However, production of pyocins during SOS response sensitizes P. aeruginosa to quinolone antibiotics by inducing cell lysis. The polynucleotide phosphorylase (PNPase) is a conserved phosphate-dependent 3′–5′ exonuclease that plays an important role in bacterial response to environmental stresses and pathogenesis by influencing mRNA and small RNA stabilities. Previously, we demonstrated that PNPase controls the type III and type VI secretion systems in P. aeruginosa. In this study, we found that mutation of the PNPase coding gene (pnp) increases the bacterial resistance to ciprofloxacin. Gene expression analyses revealed that the expression of pyocin biosynthesis genes is decreased in the pnp mutant. PrtR, a negative regulator of pyocin biosynthesis genes, is upregulated in the pnp mutant. We further demonstrated that PNPase represses the expression of PrtR on the post-transcriptional level. A fragment containing 43 nucleotides of the 5′ untranslated region was found to be involved in the PNPase mediated regulation of PrtR. Overall, our results reveled a novel layer of regulation on the pyocin biosynthesis by the PNPase in P. aeruginosa.

Objectives: Our goal was to describe Invasive Meningococcal Disease (IMD) in Southern Vietnam over the last 10 years. We characterized 109 Neisseria meningitidis strains in Southern Vietnam isolated between 1980s to 2021, that were collected from IMD (n = 44), sexually transmitted infections (n = 2), and healthy carriage (n = 63)., Methods: IMD were confirmed by bacterial culture and/or real-time polymerase chain reaction at the national reference laboratory in Pasteur Institute of Ho Chi Minh City (PIHCM). Antimicrobial resistance was determined on 31 IMD and two sexually transmitted infection isolates with E-test for chloramphenicol (CHL), penicillin (PEN), ciprofloxacin (CIP), ceftriaxone (CRO), and rifampicin (RIF). Sequencing was performed for analyzing of multilocus-sequence-typing (MLST), porA, fetA , and antibiotic resistance genes, including gyrA, penA , and rpoB ., Results: The incidence rate during this period was 0.02 per 100,000 persons/year. Serogroup B accounted for over 90% of cases (50/54). ST-1576 were mainly responsible for IMD, 27/42 MLST profiles, and associated with CHL resistance. Resistance was prevalent among IMD isolates. Thirteen were resistant to CHL (minimum inhibitory concentration [MIC] ≥16 mg/l), 12 were intermediate to PEN (MIC between 0.19 and 0.5 mg/l), and five were CIP-resistant (MIC between 0.19 and 0.5 mg/l). Particularly, one was non-susceptible to CRO (MIC at 0.125 mg/l), belonging to ST-5571 lineage. The resistance was due to carrying resistant alleles of penA and gyrA genes, and catP gene. Notably, seven isolates were resistant/non-susceptible to two or more antibiotics., Conclusion: Our results suggest the persistence of the circulating ST-1576 in Southern Vietnam, with a spread of antimicrobial resistance across the community., Competing Interests: The authors have no competing interests to declare., (© 2023 The Authors.)

Background and Objectives: Extended-spectrum β-lactamases (ESBLs) and fluoroquinolones are generally used to treat invasive Salmonella infections, but emergence of antibiotic-resistant strains are increasing worldwide. This study was aimed to investigate the distribution of ESBLs among Salmonella serogroups isolated from pediatric patients in Tehran, Iran. Materials and Methods: The study included all Salmonella isolates recovered from pediatric patients admitted to Children’s Medical Center, Tehran, Iran during 2015-2016. Bacterial isolation and identification were performed by standard biochemical and agglutination tests. Antimicrobial susceptibility testing was done according to the Clinical and Laboratory Standards Institute (CLSI). Polymerase chain reaction was used to identify the genetic determinants responsible for ESBL phenotypes. Results: A total of 138 S. enterica serovars were isolated from stool specimens, including serogroup A (1), serogroup B (18), serogroup C (41) and serogroup D (78). Forty isolates out of 138 Salmonella strains had shown ESBL-positive phenotype. All ESBL-positive isolates showed multiple resistant phenotype. Resistance to more than 3 antimicrobial agents was observed among ESBL-positive strains. The frequency of Salmonella strains carrying the blaCTX, blaTEM and blaSHV genes was 17 (12.3%), 40 (29.9%) and 4 (2.89%) respectively. Conclusion: The high rates of ESBLs positive-Salmonella strains recovered from pediatric patients is alarming and indicates a necessity to substitute the cephalosporins with a proper alternative.

The long-term persistence of antibiotic resistance in the environment, especially in drinking water, is a public health concern. Expression of an efflux pump, an important mechanism of resistance to antibiotics, usually confers a fitness cost in bacteria. In this study, we aimed to determine why antibiotic resistance conferred by overexpression of an efflux pump persisted in low-nutrient environments (TOC < 10 mg/L) such as drinking and source water in which antibiotic selective pressure might be very low or even absent. Competition experiments between wild-type Pseudomonas aeruginosa and ciprofloxacin-resistant mutants revealed that the fitness cost of ciprofloxacin resistance significantly decreased (p < 0.05) under low-nutrient (0.5 mg/L total organic carbon (TOC)) relative to high-nutrient (500 mg/L TOC) conditions. Mechanisms underlying this fitness cost were analyzed. The mexD gene expression in resistant bacteria (cip_3 strain) was significantly lower (p < 0.05) in low-nutrient conditions, with 10 mg/L TOC ((8.01 ± 0.82)-fold), than in high-nutrient conditions, with 500 mg/L TOC ((48.89 ± 4.16)-fold). Moreover, rpoS gene expression in resistant bacteria ((1.36 ± 0.13)-fold) was significantly lower (p < 0.05) than that in the wild-type strain ((2.78 ± 0.29)-fold) under low-nutrient conditions (10 mg/L TOC), suggesting a growth advantage. Furthermore, the difference in metabolic activity between the two competing strains was significantly smaller (p < 0.05) in low-nutrient conditions (5 and 0.5 mg/L TOC). These results suggest that nutrient levels are a key factor in determining the persistence of antibiotic resistance conferred by efflux pumps in the natural environment with trace amounts or no antibiotics. Unlabelled Image [ABSTRACT FROM AUTHOR]

Pseudomonas aeruginosa is an opportunistic bacterial pathogen that causes various acute and chronic infections. It is intrinsically resistant to a variety of antibiotics. However, production of pyocins during SOS response sensitizes P. aeruginosa to quinolone antibiotics by inducing cell lysis. The polynucleotide phosphorylase (PNPase) is a conserved phosphate-dependent 3′–5′ exonuclease that plays an important role in bacterial response to environmental stresses and pathogenesis by influencing mRNA and small RNA stabilities. Previously, we demonstrated that PNPase controls the type III and type VI secretion systems in P. aeruginosa. In this study, we found that mutation of the PNPase coding gene (pnp) increases the bacterial resistance to ciprofloxacin. Gene expression analyses revealed that the expression of pyocin biosynthesis genes is decreased in the pnp mutant. PrtR, a negative regulator of pyocin biosynthesis genes, is upregulated in the pnp mutant. We further demonstrated that PNPase represses the expression of PrtR on the post-transcriptional level. A fragment containing 43 nucleotides of the 5′ untranslated region was found to be involved in the PNPase mediated regulation of PrtR. Overall, our results reveled a novel layer of regulation on the pyocin biosynthesis by the PNPase in P. aeruginosa. [ABSTRACT FROM AUTHOR]

BACKGROUND: Enteric fever is the most common cause of community acquired blood stream infections in under developed and developing countries. The enteric fever is exclusive to humans and transmitted through the faeco-oral route. Though India is an endemic zone for enteric fever, the data is very scarce from Central India. The present study was undertaken to determine the prevalence of enteric fever in this region and to know the antimicrobial susceptibility pattern of the isolated typhoidal Salmonellae. MATERIAL AND METHOD: We conducted a retrospective analysis of blood culture positive cases of enteric fever over a period of two years (December 2015 to December 2017). All blood cultures submitted for suspected enteric fever and associated symptoms were included in the study. Relevant demographic, clinical and laboratory data were analyzed. RESULT: A total of 51 cases (3.56%) were of typhoidal Salmonella from a total of 1430 blood culture submission. Salmonella Typhi were 70.5% while Salmonella Paratyphi A were 29.5% of the total isolated Salmonellae. The most vulnerable age group was 10-19years (41.2%). The mean minimum inhibitory concentration of ciprofloxacin for Salmonella Typhi and Salmonella Paratyphi A are 1.20 and 1.97 μg/ml respectively. All the isolates were susceptible to ceftriaxone. Highest isolation was in the July – September quarter (35.3%). CONCLUSION: There is a high prevalence of the disease which needs urgent focus on safe water, sanitation services and also to establish guidelines for empiric therapy for enteric fever. [ABSTRACT FROM AUTHOR]

Abstract Background Enteric fever is endemic in India. Trends in antibiotic resistance in Salmonella enterica subspecies enterica serovars Typhi and Paratyphi A isolates over the past 12 years were studied. Methods A retrospective analysis of consecutive blood culture isolates of Salmonella Typhi and Salmonella Paratyphi A was performed from 2002 to 2013. Antibiotic susceptibility testing was carried out for ampicillin, chloramphenicol, cotrimoxazole, nalidixic acid (NA), ciprofloxacin and ceftriaxone by disc diffusion. The minimum inhibitory concentration of ciprofloxacin and azithromycin was determined using E-test strips. Mantel-Haenszel extended chi-square test was used for analysis of trends across years. Results Three thousand two hundred ninety-six Salmonella spp. were isolated; of which, 1905 were identified as Salmonella Typhi (58%) and 1393 as Salmonella Paratyphi A (42%). Multidrug resistance (chloramphenicol, ampicillin and cotrimoxazole) was relatively stable throughout the study period. NA resistance increased from 18% in 2007 to 100% in 2013 among Salmonella Paratyphi A isolates and from 67% to 82% among Salmonella Typhi isolates. Complete susceptibility to ceftriaxone and azithromycin was observed in this study. Conclusions Knowledge of the local patterns of resistance would help in appropriate therapy for enteric fever. With increasing rates of fluoroquinolone resistance in our hospital setting, it is probably prudent to revert back to the first-line agents for treatment and save azithromycin and third-generation cephalosporins for difficult and non-responsive cases. [ABSTRACT FROM AUTHOR]

Salmonella enterica serovar Kentucky (S. Kentucky) sequence type 198 has emerged as a global zoonotic pathogen. We explored Salmonella enterica serovar Kentucky ST198 samples from the broiler chicken supply chain and patients between 2010 and 2016. Here, we collected 180 S. Kentucky isolates from clinical cases and the poultry supply chain. We performed XbaI pulsed-field gel electrophoresis and multilocus sequence typing. We assessed mutations in the quinolone resistance-determining regions and screened for the presence of the Salmonella genomic island 1 (SGI1). We determined that 63 (35.0%) of the 180 isolates were S. Kentucky ST198. Chinese strains of S. Kentucky ST198 have a high transmission of ciprofloxacin resistance (38/63, 60.3%) and a high risk of multidrug resistance. The quinolone resistance of the S. Kentucky ST198 strain found in China may be due to mutations in its quinolone resistance-determining region. Our study firstly revealed that ciprofloxacin-resistant S. Kentucky ST198 strains can undergo cross-host transmission, thereby causing a serious foodborne public health problem in China.

Background and Objectives: Pseudomonas aeruginosa, a major cause of several infectious diseases, has become a hazardous resistant pathogen. One of the factors contributing to quinolone resistance in P. aeruginosa is mutations occurring in gyrA and parC genes encoding the A subunits of type II and IV topoisomerases, respectively, in quinolone resistance determining regions (QRDR) of the bacterial chromosome. Materials and Methods: Thirty seven isolates from patients with burn wounds and 20 isolates from blood, urine and sputum specimen were collected. Minimum Inhibitory Concentrations (MICs) of ciprofloxacin were determined by agar diffusion assay. Subsequently, QRDRs regions of gyrA and parC were amplified from resistant isolates and were assessed for mutations involved in ciprofloxacin resistance after sequencing. Results: Nine isolates with MIC≥8 µg/ml had a mutation in gyrA (Thr83→Ile). Amongst these, seven isolates also had a mutation in parC (Ser87→ Leu or Trp) indicating that the prevalent mutation in gyrA is Thr83Ile and Ser87Leu/Trp in parC. No single parC mutation was observed. Conclusion: It seems that mutations in gyrA are concomitant with mutations in parC which might lead to high-level ciprofloxacin resistance in P. aeruginosa isolates from patients with burn wounds and urinary tract infections.

H2S production has been proposed as a mechanism to explain bacterial resistance to antibiotics. In this work, we present evidence for the role of the cysJIH operon in resistance to ciprofloxacin mediated by H2S production with different sulfate as the only sulfur source. We found that the products of the cysJIH operon are involved in ciprofloxacin resistance by increasing both, the levels of H2S and reduced thiols apparently counteracting antimicrobial-induced reactive oxygen species (ROS). This protective effect was observed only when bacteria were cultured in the presence of sulfate, but not with cysteine, as the sole sulfur source.