Search

Background: The emergence of ESBLs producing cephalosporin-resistant Escherichia coli isolates poses a threat to public health. This study aims to decipher the genetic landscape and gain insights into ESBL-producing E. coli strains belonging to the high-risk clone ST410 from pediatric patients. Methods: 29 E. coli ST410 isolates were collected from young children and subjected to antimicrobial susceptibility testing, Whole-genome sequencing (WGS), serotype analysis, MLST, ESBL genes, virulence genes, and plasmid profiling. Results: Antimicrobial susceptibility testing demonstrated a high level of resistance to cephalosporins followed by aminoglycoside, sulfonamide, carbapenem and penicillin group of antibiotics. However, n=20/29 shows MDR phenotype. Phylogenetic group B2 (n=15) dominated, followed by group D (n=7), group A (n=4), and group B1 (n=3). Serotyping analysis identified O1:H7 (n=8), O2:H1 (n=6), O8:H4 (n=5), O16:H5 (n=4), and O25:H4 (n=3). Other serotypes identified included O6:H1, O15:H5, and O18:H7 (n=1 each). The most commonly detected ESBL genes were blaCTX-M, (n=26), followed by blaTEM (n=23), and blaSHV (n=18). Additionally, blaOXA-1 (n=10), blaOXA-48 (n=5), blaKPC-2 (n=3), blaKPC-3 (n=2), blaNDM-1 (n=4), blaNDM-5 (n=1), blaGES-1 (n=2), blaGES-5 (n=1), and blaCYM-1 (n=3). Notable virulence genes identified within the ST410 isolates included fimH (n=29), papC (n=24), hlyA (n=22), and cnf1 (n=18), among others. Diverse plasmids were observed including IncFIS, IncX4, IncFIA, IncCol, IncI2 and IncFIC with transmission frequency ranges from 1.3X10-2 to 2.7X10-3. Conclusion: The ST410 clone exhibited a complex resistance profile, diverse serotypes, the presence of specific resistance genes (ESBL genes), virulence gene repertoire, and diverse plasmids. The blaCTX-M was the most prevalent ESBL gene detected. [ABSTRACT FROM AUTHOR]

It was in the 1800s when the first public publications about the infection and treatment of gonorrhoea were released. However, the first prevention programmes were only published a hundred years later. In the 1940s, the concept of vaccination was introduced into clinical prevention programmes to address early sulphonamide resistance. Since then, tons of publications on Neisseria gonorrhoeae are undisputed, around 30,000 publications today. Currently, the situation seems to be just as it was in the last century, nothing has changed or improved. So, what are we doing wrong? And more importantly, what might we do? The review presented here aims to review the current situation regarding the resistance mechanisms, prevention programmes, treatments, and vaccines, with the challenge of better understanding this special pathogen. The authors have reviewed the last five years of advancements, knowledge, and perspectives for addressing the Neisseria gonorrhoeae issue, focusing on new therapeutic alternatives. [ABSTRACT FROM AUTHOR]

This article presents a study on the usage patterns of antimicrobial agents in preventing surgical site infections (SSIs) at a hospital in Kerala, India. The study found that cephalosporins were the most commonly used antibiotics, and emphasized the importance of evaluating their appropriateness and potential resistance concerns. The findings align with global trends and highlight the need for tailored antimicrobial strategies to optimize patient care and minimize the risk of antimicrobial resistance. [Extracted from the article]

BackgroundThe emergence of ESBLs producing cephalosporin-resistant Escherichia coli isolates poses a threat to public health. This study aims to decipher the genetic landscape and gain insights into ESBL-producing E. coli strains belonging to the high-risk clone ST410 from pediatric patients.Methods29 E. coli ST410 isolates were collected from young children and subjected to antimicrobial susceptibility testing, Whole-genome sequencing (WGS), serotype analysis, MLST, ESBL genes, virulence genes, and plasmid profiling.ResultsAntimicrobial susceptibility testing demonstrated a high level of resistance to cephalosporins followed by aminoglycoside, sulfonamide, carbapenem and penicillin group of antibiotics. However, n=20/29 shows MDR phenotype. Phylogenetic group B2 (n=15) dominated, followed by group D (n=7), group A (n=4), and group B1 (n=3). Serotyping analysis identified O1:H7 (n=8), O2:H1 (n=6), O8:H4 (n=5), O16:H5 (n=4), and O25:H4 (n=3). Other serotypes identified included O6:H1, O15:H5, and O18:H7 (n=1 each). The most commonly detected ESBL genes were blaCTX-M, (n=26), followed by blaTEM (n=23), and blaSHV (n=18). Additionally, blaOXA-1 (n=10), blaOXA-48 (n=5), blaKPC-2 (n=3), blaKPC-3 (n=2), blaNDM-1 (n=4), blaNDM-5 (n=1), blaGES-1 (n=2), blaGES-5 (n=1), and blaCYM-1 (n=3). Notable virulence genes identified within the ST410 isolates included fimH (n=29), papC (n=24), hlyA (n=22), and cnf1 (n=18), among others. Diverse plasmids were observed including IncFIS, IncX4, IncFIA, IncCol, IncI2 and IncFIC with transmission frequency ranges from 1.3X10-2 to 2.7X10-3.ConclusionThe ST410 clone exhibited a complex resistance profile, diverse serotypes, the presence of specific resistance genes (ESBL genes), virulence gene repertoire, and diverse plasmids. The blaCTX-M was the most prevalent ESBL gene detected.

Simple Summary: Little is known on the distribution of beta-lactam resistant Gram-negative bacteria in the gut of Madagascan animals. To increase respective knowledge, swabs from 49 animal stool droppings were collected in the Madagascan Tsimanapesotsa National Park and assessed by microbial culture, antimicrobial susceptibility testing, and sequence analysis. Third generation cephalosporine resistance, predominantly mediated by ampC-type beta-lactamases, was the most frequently observed beta-lactam resistance phenotype. Future studies should assess whether and to what extent an exchange of resistant isolates between humans and animals facilitates a local spread of resistant bacteria. Third generation cephalosporin-resistant (3GCR) Enterobacterales are known to be prevalent in Madagascar, with high colonization or infection rates in particular in Madagascan patients. Extended spectrum beta-lactamases (ESBLs) have been reported to be the predominant underlying resistance mechanism in human isolates. So far, little is known on antimicrobial resistance and its molecular determinants in Enterobacterales and other bacteria causing enteric colonization of Madagascan wild animals. To address this topic, swabs from 49 animal stool droppings were collected in the Madagascan Tsimanapesotsa National Park and assessed by cultural growth of bacterial microorganisms on elective media. In addition to 7 Acinetobacter spp., a total of 31 Enterobacterales growing on elective agar for Enterobacterales could be isolated and subjected to whole genome sequencing. Enterobacter spp. was the most frequently isolated genus, and AmpC-type beta-lactamases were the quantitatively dominating molecular resistance mechanism. In contrast, the blaCTX-M-15 gene, which has repeatedly been associated with 3GC-resistance in Madagascan Enterobacterales from humans, was detected in a single Escherichia coli isolate only. The identification of the fosfomycin-resistance gene fosA in a high proportion of isolates is concerning, as fosfomycin is increasingly used to treat infections caused by multidrug-resistant bacteria. In conclusion, the proof-of-principle assessment indicated a high colonization rate of resistant bacteria in stool droppings of Madagascan wild animals with a particular focus on 3GCR Enterobacterales. Future studies should confirm these preliminary results in a more systematic way and assess the molecular relationship of animal and human isolates to identify potential routes of transmission. [ABSTRACT FROM AUTHOR]

Introduction: Plasmid-mediated class C ß-lactamase (pAmpC) is a member of broad-spectrum ß-lactamase that spreads worldwide. However, its prevalence was under-evaluated. Objective: To characterize the prevalence and distribution of pAmpC types in 294 cefoxitin (FOX) and third-generation cephalosporin (3GC) resistant Enterobacteriaceae collected in several regions of Thailand and Vietnam in 2018 and 2020. Methods: Multiplex Polymerase Chain Reaction (PCR) for pAmpC identification was utilized to investigate prevalence and diversification of pAmpC among 294 cefoxitin and third-generation cephalosporin resistant Enterobacteriaceae isolated from Thailand (n= 197) and Vietnam (n= 97). Results: The prevalence of pAmpC was 37.1 % found in second and third-generation cephalosporin resistant Enterobacteriaceae. CMY-2 like was prominent in Thailand and Vietnam; however, prevalence of CMY-2 was varied in each hospital. DHA contributed 25.7 %, ACT/MIR rate was dominant in Chiang Rai hospital, reached 100 % in Thanh Hoa Pediatrics hospital. Worrisome, 3.7 % - isolates carried two types of pAmpC. The incidence of pAmpC in Vietnam was significantly higher than those in Thailand. Conclusions: These findings provide evidence-based of highly spreading and diversified distribution of transferable AmpC among Enterobacteriaceae in two Asia-Pacific countries.

The bacterial PASTA kinase, IreK, is required for intrinsic cephalosporin resistance in the Gram‐positive opportunistic pathogen, Enterococcus faecalis. IreK activity is enhanced in response to cell wall stress, such as cephalosporin exposure. The downstream consequences of IreK activation are not well understood in E. faecalis, but recent work in other low‐GC Gram‐positive bacteria demonstrated PASTA kinase‐dependent regulation of MurAA, an enzyme that performs the first committed step in the peptidoglycan synthesis pathway. Here, we used genetic suppressor selections to identify MurAA as a downstream target of IreK signaling in E. faecalis. Using complementary genetic and biochemical approaches, we demonstrated that MurAA abundance is regulated by IreK signaling in response to physiologically relevant cell wall stress to modulate substrate flux through the peptidoglycan synthesis pathway. Specifically, the IreK substrate, IreB, promotes proteolysis of MurAA through a direct physical interaction in a manner responsive to phosphorylation by IreK. MurAB, a homolog of MurAA, also promotes MurAA proteolysis and interacts directly with IreB. Our results therefore establish a connection between the cell wall stress sensor IreK and one critical physiological output to modulate peptidoglycan synthesis and drive cephalosporin resistance. [ABSTRACT FROM AUTHOR]

It was in the 1800s when the first public publications about the infection and treatment of gonorrhoea were released. However, the first prevention programmes were only published a hundred years later. In the 1940s, the concept of vaccination was introduced into clinical prevention programmes to address early sulphonamide resistance. Since then, tons of publications on Neisseria gonorrhoeae are undisputed, around 30,000 publications today. Currently, the situation seems to be just as it was in the last century, nothing has changed or improved. So, what are we doing wrong? And more importantly, what might we do? The review presented here aims to review the current situation regarding the resistance mechanisms, prevention programmes, treatments, and vaccines, with the challenge of better understanding this special pathogen. The authors have reviewed the last five years of advancements, knowledge, and perspectives for addressing the Neisseria gonorrhoeae issue, focusing on new therapeutic alternatives.

ABSTRACT: We investigated the cephalosporin resistance of Escherichia coli from waterfowl among different breeding mode farms. In 2021, we isolated 200 strains of E. coli from waterfowl feces samples collected from Sichuan, Heilongjiang, and Anhui provinces. The key findings are: Out of the 200 strains, 80, 80, and 40 strains were isolated from waterfowl feces samples in intensive, courtyard, and outdoor breeding mode farms, respectively. The overall positive rate of the ESBL phenotype, detecting by the double disk diffusion method, was 68.00% (136/200). In particular, the rates for intensive, courtyard, and outdoor breeding modes were 98.75%, 36.25%, and 70.00%, respectively. Results of MIC test showed drug resistance rates in the intensive breeding mode: 100.00% for cephalothin, 38.75% for cefoxitin, 100.00% for cefotaxime, and 100.00% for cefepime. In courtyard breeding mode, the corresponding rates were 100.00%, 40.00%, 63.75%, and 45.00%, respectively. In outdoor breeding mode, the corresponding rates were 100.00%, 52.50%, 82.50%, and 77.50%, respectively. The PCR results for blaCTX-M, blaTEM, blaOXA, and blaSHV showed the detection rate of blaCTX-M was highest at 75.50%, with blaCTX-M-55 is the main subtype gene, followed by blaTEM at 73.50%. We screened 58 donor strains carrying blaCTX-M-55, including 52 strains from the intensive breeding mode. These donor bacteria can transfer different plasmids to recipient E. coli J53, resulting in recipient bacteria acquiring cephalosporin resistance, and the conjugational transfer frequency ranged from 1.01 × 10-5 to 6.56 × 10-2. The transferred plasmids remained stable in recipient bacteria for up to several days without significant adaptation costs observed. During molecular typing of E. coli with conjugational transfer ability, the blaCTX-M-55 was found to be widely present in different ST strains with several phylogenetic groups. In summary, cephalosporin resistance of E. coli carried by waterfowl birds in intensive breeding mode farm was significantly higher than in courtyard and outdoor mode farms. The blaCTX-M-55 subtype gene was the prevalent ARGs and can be horizontally transferred through plasmids, which plays a key role in the spread of cephalosporin drug resistance.

Third generation cephalosporin-resistant (3GCR) Enterobacterales are known to be prevalent in Madagascar, with high colonization or infection rates in particular in Madagascan patients. Extended spectrum beta-lactamases (ESBLs) have been reported to be the predominant underlying resistance mechanism in human isolates. So far, little is known on antimicrobial resistance and its molecular determinants in Enterobacterales and other bacteria causing enteric colonization of Madagascan wild animals. To address this topic, swabs from 49 animal stool droppings were collected in the Madagascan Tsimanapesotsa National Park and assessed by cultural growth of bacterial microorganisms on elective media. In addition to 7 Acinetobacter spp., a total of 31 Enterobacterales growing on elective agar for Enterobacterales could be isolated and subjected to whole genome sequencing. Enterobacter spp. was the most frequently isolated genus, and AmpC-type beta-lactamases were the quantitatively dominating molecular resistance mechanism. In contrast, the blaCTX-M-15 gene, which has repeatedly been associated with 3GC-resistance in Madagascan Enterobacterales from humans, was detected in a single Escherichia coli isolate only. The identification of the fosfomycin-resistance gene fosA in a high proportion of isolates is concerning, as fosfomycin is increasingly used to treat infections caused by multidrug-resistant bacteria. In conclusion, the proof-of-principle assessment indicated a high colonization rate of resistant bacteria in stool droppings of Madagascan wild animals with a particular focus on 3GCR Enterobacterales. Future studies should confirm these preliminary results in a more systematic way and assess the molecular relationship of animal and human isolates to identify potential routes of transmission.

This study investigates the genetic traits and transmission mechanisms of cephalosporin-resistant Escherichia coli in tropical aquatic environments in Singapore. From 2016 to 2020, monthly samples were collected from wastewater treatment plants, marine niches, community sewage, beaches, reservoirs, aquaculture farms, and hospitals, yielding 557 isolates that were analyzed for antimicrobial resistance genes (ARGs) and mobile genetic elements (MGEs) using genomic methods. Findings reveal significant genotypic similarities between environmental and hospital-derived strains, particularly the pandemic E. coli ST131. Environmental strains exhibited high levels of intrinsic resistance mechanisms, including mutations in porins and efflux pumps, with key ARGs such as CMY-2 and NDM-9 predominantly carried by MGEs, which facilitate horizontal gene transfer. Notably, pathogenic EPEC and EHEC strains were detected in community sewage and aquaculture farms, posing substantial public health risks. This underscores the critical role of these environments as reservoirs for multidrug-resistant pathogens and emphasizes the interconnectedness of human activities and environmental health. [Display omitted] • Widespread cephalosporin-resistant E. coli identified in various aquatic environments in Singapore. • Genotypic similarities indicate AMR dissemination between environmental and hospital E. coli strains. • Mobile genetic elements critically transmit cephalosporin resistance genes among E. coli strains. • Five-year sampling captures seasonal and spatial variations in resistant E. coli populations.. • Findings highlight the need for integrated strategies to curb AMR spread. [ABSTRACT FROM AUTHOR]

Among 114 clinical Neisseria gonorrhoeae isolates collected in Vietnam during 2019–2020, we detected 15 of subclone sequence type 13871 of the FC428 clonal complex. Fourteen sequence type 13871 isolates with mosaic penA allele 60.001 were ceftriaxone or cefixime nonsusceptible, and 3/14 were azithromycin nonsusceptible. Emergence of this subclone threatens treatment effectiveness.

Phylogenetic distribution and extended spectrum β-lactamase (ESBL) activity of Escherichia coli recovered from surface and reclaimed water in the mid-Atlantic U.S. were evaluated. Among 488 isolates, phylogroups B1 and A were the most and least prevalent, respectively. Water type, but not season, affected phylogroup distribution. The likelihood of detecting group A isolates was higher in reclaimed than pond (P < 0.01), freshwater river (P < 0.01) or brackish river (P < 0.05) water. Homogeneity in group distribution was lowest in pond water, where group B1 comprised 50% of isolates. Only 16 (3.3%) isolates exhibited phenotypic resistance to one or more cephalosporins tested and only four had ESBL activity, representing groups B1, B2 isolates, and D. Phylogroup was a factor in antimicrobial resistance (P, 0.05), with group A (8.7%) and D (1.6%) exhibiting the highest and lowest rates. Resistance to cefoxitin was the most prevalent. Multi- versus single drug resistance was affected by phylogroup (P < 0.05) and more likely in groups D and B1 than A which carried resistance to cefoxitin only. The most detected b-lactam resistance genes were blaCMY-2 and blaTEM. Water type was a factor for blaCTX-M gene detection (P < 0.05). Phenotypic resistance to cefotaxime, ceftriaxone, cefuroxime and ceftazidime, and genetic determinants for ESBL-mediated resistance were found predominantly in B2 and D isolates from rivers and reclaimed water. Overall, ESBL activity and cephalosporin resistance in reclaimed and surface water isolates were low. Integrating data on ESBL activity and b-lactam resistance among E. coli populations can inform decisions on safety of irrigation water sources and One Health. [ABSTRACT FROM AUTHOR]

ABSTRACT Enterococcus faecalis is an opportunistic pathogen and a major cause of severe nosocomial infections. Treatment options against enterococcal infections are declining due to the resistance of enterococci to numerous antibiotics. A key risk factor for developing enterococcal infections is treatment with cephalosporin antibiotics, to which enterococci are intrinsically resistant. For susceptible organisms, cephalosporins inhibit bacterial growth by acylating the active site of penicillin-binding proteins (PBPs), key enzymes that catalyze peptidoglycan cross-linking. Two specific PBPs of enterococci, Pbp4(5) and PbpA(2b), exhibit low reactivity toward cephalosporins, allowing these PBPs to cross-link peptidoglycan in the presence of cephalosporins to drive resistance in enterococci, but the mechanisms by which these PBPs are regulated are poorly understood. The CroS/R two-component signal transduction system (TCS) is also required for cephalosporin resistance. Activation of CroS/R by cephalosporins leads to CroR-dependent changes in gene expression. However, the specific genes regulated by CroS/R that are responsible for cephalosporin resistance remain largely unknown. In this study, we characterized CroR-dependent transcriptome remodeling by RNA-seq, identifying pbp4(5) as a CroR regulon member in multiple, diverse lineages of E. faecalis. Through genetic analysis of the pbp4(5) and croR promoters, we uncovered a CroR-dependent regulatory motif. Mutations in this motif to disrupt CroR-dependent upregulation of pbp4(5) in the presence of cell wall stress resulted in a reduction of resistance to cephalosporins in E. faecalis, demonstrating that enhanced production of Pbp4(5) and likely other proteins involved in peptidoglycan biogenesis by the CroS/R system drives enterococcal cephalosporin resistance. IMPORTANCE Investigation into molecular mechanisms used by enterococci to subvert cephalosporin antibiotics is imperative for preventing and treating life-threatening infections. In this study, we used genetic means to investigate the functional output of the CroS/R TCS required for enterococcal resistance to cephalosporins. We found that enhanced production of the penicillin-binding protein Pbp4(5) upon exposure to cell wall stress was mediated by CroS/R and was critical for intrinsic cephalosporin resistance of E. faecalis.

Abstract By 2010, systems set up to monitor the antimicrobial resistance of pathogenic bacteria and antimicrobial usage identified a sustained increase regarding third‐ and fourth‐generation cephalosporin resistance in French pig production. This sector mobilised and collectively committed to responsible action in the following months. This led to a multi‐professional voluntary stewardship programme that was started in 2011. A consensus of veterinary opinion led to the definition of restrictive rules on the prescription of the third‐ and fourth‐generation cephalosporins targeted by the antimicrobial stewardship programme (ASP). All pig sector professionals, including farmers, were informed. Existing monitoring systems for usage and resistance were supplemented by data from the records of veterinarians' cephalosporin deliveries and from individual pig farm surveys investigating antimicrobial usage. The second step, from 2014, entailed regulatory measures that consolidated the programme by setting quantitative reduction objectives and specifying the terms and conditions for prescribing and dispensing a list of critical antimicrobial molecules including cephalosporins. All the data sources confirmed a significant fall of more than 90% in cephalosporin usage in the French pig production sector between 2010 and 2016. Monitoring systems recorded that the resistance of commensal and pathogenic Escherichia coli isolates also tended to decrease over the same period. The stewardship programme proved highly effective in reducing usage and containing resistance, illustrating the efficiency of a well‐defined multi‐professional strategy.

In this study, the susceptibility to cephalosporins of 74 Salmonella isolates, including 16 isolates from farm animals and 58 isolates from poultry was assessed by the disc diffusion method. ESBL production was evaluated by combined disc diffusion method (CDDM) and double disc synergy test (DDST). The genetic relatedness of isolates was investigated by the Rep-PCR method. The highest prevalence of resistance was observed against cefotaxime (27%) and the least – against cefixime (4%). None of the isolates was ESBL positive. The Rep-PCR generated 54 reproducible fingerprint patterns for all isolates and grouped them in four clusters and six singletons. Due to public health risk of cross contamination, it is important to have sufficient information on the occurrence of these resis-tant isolates.

Cephalosporins are the first-line therapy antibiotics used in the treatment of gram-negative bacterial infections. However, high prevalence of cephalosporins resistance in Klebsiella pneumoniae and Escherichia coli has been reported worldwide. Studies conducted in Uganda reported high incidences of cephalosporin resistance (CR). Successive studies at Mulago National Referral Hospital indicated a decline in the resistance levels pointing to the need for regular antibiotic resistance surveillance. Therefore, this study carried out molecular characterization of CR determinants in E. coli and K. pneumoniae isolated from patients attending Kampala International University Teaching Hospital (KIU-TH). A retrospective study using E. coli and K. pnuemoniae samples previously obtained from surgical wounds and urinary tract infections among patients treated at KIU-TH between September 2016 and August 2018 was conducted. Biochemical assays were used to confirm the identity of the samples. Combined disc and boronic acid assays were used to determine the cephalosporine resistance profile of the isolates. Multiplex PCR amplification was used to characterize the extended spectrum beta-lactmase (ESBL) encoding genes. The study revealed that E. coli (130/81.2%) isolates were more predominant than K. pneumoniae (30/18.8%) among the archived samples. K. pneumoniae showed the highest phenotypic resistance with a mean prevalence of 90.6% but comparable to that of E. coli (89.3%). Of the 160 isolates screened, 105 (65.6%) were ESBL producers. Multiplex PCR revealed that the most predominant ESBL encoding gene was blaSHV at a prevalence of 42.0%, followed by blaTEM at 27.3%, blaCTX-M at 22.4% and blaCTX-M-15 at 8.4%. The incidence of phenotypic resistance and distribution of ESBL genes were significantly higher in patients of Ishaka division. Our study reports a high prevalence of cephalosporin-resistant E. coli and K. pnuemoniae isolated from patients attending KIU-TH and highlights the need for routine screening of antimicrobial resistance in health-care facilities so as to guide clinicians on the rational prescription of antibiotics. List of abbreviations: ATCC: American Type Culture Collection; ESBL: extended spectrum beta-lactmases; AmpC: aminopenicillin cephalosporinase; CTX-M: cephotaxime (M-first detected in Munich) hydrolyzing capabilities; CTX-M-U: cephotaxime hydrolyzing capabilities gene Universal primer; SHV: sulfhydryl variables (variant-2); CMY-2: cephamycins (variant-2); TEM: temoneira; ACT-1: AmpC type (variant-1); Bla: Beta lactam; DNA: deoxyribonucleic acid; PCR: Polymerase chain reaction; MNRH: Mulago National Referral Hospital; MRRH: Mbarara Regional Referral Hospital; KRRH: Kabale Regional Referral Hospital (KRRH); KIU-TH: Kampala International University Teaching Hospital; CDL: Central Diagnostic Laboratory; CoVAB: College of Veterinary Medicine, Animal Resources and Biosecurity; CR: cephalosporin resistance [ABSTRACT FROM AUTHOR]

We evaluated the impact of the administration of two Escherichia coli probiotic strains (ED1a and Nissle 1917) to pigs on the gut carriage or shedding of extended-spectrum beta-lactamase-producing E. coli. The probiotics were given to four sows from 12 days before farrowing to the weaning day, and to the 23 piglets (infected treated group (IPro)) from birth to the age of 49 days. Four other sows and their 24 piglets (infected non-treated group (INT)) did not receive the probiotics. IPro and INT piglets (n = 47) were orally inoculated with the strain E. coli 17–348F-RifR carrying the blaCTX−M-1 gene and resistant to rifampicin. Cefotaxime-resistant (CTXR) E. coli and rifampicin-resistant (RifR) E. coli were cultured and excretion of probiotics was studied using PCR on individual faecal and post-mortem samples, and from manure collected after the challenge with resistant E. coli. CTXR and RifR E. coli isolates were characterized to detect transfer of the blaCTX−M-1 to other strains.. Overall, there was no significant reduction in faecal excretion of CTXR and RifR E. coli in IPro pigs compared with INT pigs, although the CTXR and RifR E. coli titres were slightly, but significantly lower in the colon, caecum and rectum at post mortem. Excretion of the probiotics decreased with age, but Nissle 1917 was detected in most pigs at post-mortem. No transfer of the blaCTX−M-1 gene to probiotic and other E. coli strains was detected. In conclusion, in our experimental conditions, the used probiotics did not reduce shedding of the challenge strain.

Recent reports have established the emergence and dissemination of extensively drug resistant (XDR) H58 Salmonella Typhi clone in Pakistan. In India where typhoid fever is endemic, only sporadic cases of ceftriaxone resistant S. Typhi are reported. This study aimed at elucidating the phylogenetic evolutionary framework of ceftriaxone resistant S. Typhi isolates from India to predict their potential dissemination. Five ceftriaxone resistant S. Typhi isolates from three tertiary care hospitals in India were sequenced on an Ion Torrent Personal Genome Machine (PGM). A core genome single-nucleotide-polymorphism (SNP) based phylogeny of the isolates in comparison to the global collection of MDR and XDR S. Typhi isolates was built. Two of five isolates were additionally sequenced using Oxford Nanopore MinION to completely characterize the plasmid and understand its transmission dynamics within Enterobacteriaceae. Comparative genomic analysis and detailed plasmid characterization indicate that while in Pakistan (4.3.1 lineage I) the XDR trait is associated with bla CTX-M-15 gene on IncY plasmid, in India (4.3.1 lineage II), the ceftriaxone resistance is due to short term persistence of resistance plasmids such as IncX3 (bla SHV-12) or IncN (bla T EM-1B + bla DHA-1). Considering the selection pressure exerted by the extensive use of ceftriaxone in India, there are potential risks for the occurrence of plasmid transmission events in the predominant H58 lineages. Therefore, continuous monitoring of S. Typhi lineages carrying plasmid-mediated cephalosporin resistant genes is vital not just for India but also globally. • S. Typhi to develop cephalosporin resistance by acquiring diverse plasmids from other Enterobacteriaceae. • Independent acquisition of drug-resistant plasmids such as IncX3 and IncN with genes encoding beta-lactamases in H58 lineage II of S. Typhi. • A short-term persistence of drug-resistant plasmids in H58 lineage II can be the reason for the sporadic cases cephalosporin resistant S. Typhi in India. • Plasmid acquisition and maintenance of cephalosporin resistant S. Typhi appears to be specific to the phylogenetic lineage. • Critical strategies in monitoring and control of cephalosporin resistant S. Typhi is needed to tackle further public health crisis. [ABSTRACT FROM AUTHOR]

By 2010, systems set up to monitor the antimicrobial resistance of pathogenic bacteria and antimicrobial usage identified a sustained increase regarding third‐ and fourth‐generation cephalosporin resistance in French pig production. This sector mobilised and collectively committed to responsible action in the following months. This led to a multi‐professional voluntary stewardship programme that was started in 2011. A consensus of veterinary opinion led to the definition of restrictive rules on the prescription of the third‐ and fourth‐generation cephalosporins targeted by the antimicrobial stewardship programme (ASP). All pig sector professionals, including farmers, were informed. Existing monitoring systems for usage and resistance were supplemented by data from the records of veterinarians' cephalosporin deliveries and from individual pig farm surveys investigating antimicrobial usage. The second step, from 2014, entailed regulatory measures that consolidated the programme by setting quantitative reduction objectives and specifying the terms and conditions for prescribing and dispensing a list of critical antimicrobial molecules including cephalosporins. All the data sources confirmed a significant fall of more than 90% in cephalosporin usage in the French pig production sector between 2010 and 2016. Monitoring systems recorded that the resistance of commensal and pathogenic Escherichia coli isolates also tended to decrease over the same period. The stewardship programme proved highly effective in reducing usage and containing resistance, illustrating the efficiency of a well‐defined multi‐professional strategy. [ABSTRACT FROM AUTHOR]

Background: Prevalence of extended-spectrum beta-lactamase-producing Escherichia coli (ESBL-E. coli) is increasing worldwide, but greatly varies geographically. We compared the prevalence of ESBL-E. coli infections at four distinct health care facilities in San Francisco, California. Methods: Antimicrobial susceptibility reports were obtained for E. coli isolates from (1) a county hospital, (2) a public skilled nursing facility, (3) a university hospital, and (4) a Veterans Affairs (VA) Medical Center. We compared change in frequency of ESBL-E. coli and antimicrobial resistance to trimethoprim-sulfamethoxazole between 2012 and 2018. Results: From 2012 to 2018, frequency of ESBL-E. coli increased in urine and nonurine isolates from the county hospital (urine: 1.1% per year, 95% confidence interval [CI]: 0.5–1.6, p < 0.01; nonurine: 1.9% per year, 95% CI: 0.9–2.9, p < 0.01) and in urine isolates from the VA hospital (0.9% per year, 95% CI: 0.3–1.4, p < 0.01). The frequency of trimethoprim-sulfamethoxazole resistance fluctuated in all facilities. Conclusions: At the skilled nursing facility, the prevalence of ESBL-E. coli was highest, but remained stable over time, while the prevalence of ESBL-E. coli increased among urine and nonurine isolates at the county hospital and urine isolates at the VA hospital. The temporal trend of ESBL-E. coli infections, even within one city, varied by health care facility. [ABSTRACT FROM AUTHOR]

White stork (Ciconia ciconia) may act as a reservoir and vehicle of cephalosporin resistant (CR) Escherichia coli. Between 2011 and 2014, we sampled white storks from colonies exposed to different degrees of anthropic pressure across the major areas of natural distribution of white storks in Spain. Cloacal swab samples (n = 467) were obtained from individuals belonging to 12 different colonies from six different regions. Additionally, 70 samples were collected from recently deposited droppings at the base of nesting platforms. We phenotypically characterized E. coli isolates, confirmed presence of CR genes and classified plasmids. Risk factors for acquiring these genes were assessed. Overall, 8.8% (41 out of 467) storks carried CR E. coli in their cloaca and five (7.1%) were identified from recently deposited droppings; therefore, 46 isolates were further characterized. Of them, 20 contained blaCTX–M–1, nine blaCMY–2, six blaCTX–M–14, four blaSHV–12, three blaCTX–M–15, two blaCTX–M–32, one blaCTX–M–1 together with blaCMY–2, and one blaCTX–M–1 together with blaSHV–12. All were multidrug-resistant, and four harbored the plasmid-mediated colistin resistance mcr-1 gene. CR genes were associated with the presence of IncI1, IncFIB, and IncN replicon families. XbaI-macrorestriction analysis revealed a great diversity among most of the XbaI-PFGE types, but indistinguishable types were also seen with isolates obtained from different locations. Clonal complex 10 was the most common among CR E. coli and two blaCTX–M–15 positive isolates were identified as B2-ST131. Carriage of CR E. coli was significantly higher in colonies located close to solid urban waste disposal sites in which foraging on human waste was more likely and in one case to cattle grazing. The co-occurrence of blaCMY–2 and mcr-1 on plasmids of E. coli isolated from wild birds as early as 2011 is of note, as the earliest previous report of mcr-1 in wild birds is from 2016. Our study shows that foraging at landfills and in association with cattle grazing are important risk factors for the acquisition of CR E. coli in white storks.

Escherichia coli carrying blaCTX–M–1 mediating resistance to extended-spectrum cephalosporins was recently described as a new genotype in Norwegian broiler production. The aim of this study was to characterize these isolates (n = 31) in order to determine whether the emergence of the genotype was caused by clonal expansion or horizontal dissemination of blaCTX–M–1-carrying plasmids. All included isolates were subjected to whole genome sequencing. Plasmid transferability was determined by conjugation, and plasmid replicons in the transconjugants were described using PCR-based replicon typing. Plasmid sizes were determined using S1 nuclease digestion. Plasmids in a subset of strains were reconstructed and compared to plasmids from broiler production in other European countries. The isolates belonged to nine different sequence types (STs), with the largest group being ST57 (n = 12). The vast majority of blaCTX–M–1-carrying plasmids were conjugative. All transconjugants were positive for the IncI1-Iγ replicon, and several also harbored the IncFIB replicon. Highly similar plasmids were present in different E. coli STs. Additionally, high similarity to previously published plasmids was detected. A reconstructed plasmid from an ST57 isolate harbored both IncI1-Iγ and IncFIB replicons and was considered to be co-integrated. The presence of one large plasmid was confirmed by S1 nuclease digestion. Our results show that dissemination of blaCTX–M–1 in Norwegian broiler production is due to both clonal expansion and horizontal transfer of plasmids carrying blaCTX–M–1. The blaCTX–M–1/IncI1-Iγ plasmids grouped into two main lineages, namely clonal complex (CC)-3 and CC-7. The genetic diversity at both strain and plasmid level indicates multiple introductions to Norway. We also show that the blaCTX–M–1 plasmids circulating in Norwegian broiler production are highly similar to plasmids previously described in other countries.

Background: Septicemia in children in mainland China has recently become a public health concern. Methods: A meta-analysis was performed on studies investigating the prevalence of cephalosporin-resistant Escherichia coli isolated from children with septicemia in mainland China from 2007 to 2017 following a search of relevant databases. Results: A total of 43 articles reporting 11 cephalosporins were included in the review. The results of the meta-analysis revealed that for the first-generation cephalosporins, the pooled summarized prevalence of resistance to cefazolin was 74.96% (95% confidence interval [CI]: 64.79–83.91) and cephalothin resistance was 62.28% (95% CI: 36.45–100). Regarding the second-generation cephalosporins, cefoxitin-resistant E. coli comprised 23.85% (95% CI: 10.60–40.40) and cefuroxime resistance was 60.32% (95% CI: 51.25–68.73). For the third-generation cephalosporins, the pooled summarized prevalence of resistance was 51.34% for cefotaxime (95% CI: 40.08–62.54), 40.43% for ceftazidime (95% CI: 31.07–50.15), 45.51% for cefoperazone (95% CI: 20.41–70.61), 12.10% for cefoperazone/sulbactam (95% CI: 6.55–18.76), 62.99% for ceftriaxone (95% CI: 55.00–70.98), and 0% for cefotetan. Among the fourth-generation cephalosporins, resistance to cefepime was 34.08% (95% CI: 25.91–43.31). Conclusions: Most third-generation cephalosporins (e.g., cefotaxime and ceftriaxone) retained high resistance rates throughout the 11-year study period without significant changes. The new fourth-generation cephalosporin, cefepime, is rapidly gaining resistance. Interestingly, ceftazidime, cefepime, and cefoperazone/sulbactam showed a recent decreasing trend of drug resistance. These situations may present a risk for treating children with septicemia and should be closely monitored and treated. [ABSTRACT FROM AUTHOR]

The clinical importance of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli has increased steadily over the years. The presence of the blaTEM, blaSHV, and blaCTX-M genes in the environment has been recently recognized as an important issue in the dissemination of resistance to cephalosporins. Food animals are considered important vectors for transfer of ESBL genes from the environment to humans. The objective of this study was to characterize the ESBL genes (blaTEM, blaSHV, and blaCTX-M types) that were most prevalent among 343 ceftazidime-resistant E. coli isolates (17 batches from 12 different farms) obtained from cloacal swabs of broiler chicken in southern Brazil. The blaSHV, blaCTX-M, blaTEM, blaIMP-type, blaVIM-type, blaNDM-1, blaKPC-type, blaGES-type, blaOXA-48, and mcr-1 genes were evaluated by polymerase chain reaction. A total of 27 (7.9%) E. coli isolates were positive for ESBL genes as follows: 24 for blaCTX-M (23 blaCTX-M-2 Group and 1 blaCTX-M-8) and 3 for blaSHV (2 blaSHV-2a and 1 blaSHV-18). A random sample of 32 ceftazidime/cefotaxime-resistant isolates that were negative for ESBL genes were evaluated for the presence of blaCMY-2 and 24 (75%) tested positive. We detected the blaCMY-2 gene in isolates from all farms. All isolates positive for ESBL or blaCMY-2 are considered multidrug resistant (resistant to at least three antibiotic classes). Our results suggest that broiler chickens are an important reservoir of blaCMY-2 and ESBL genes, including blaSHV-2a, described for the first time in animals originating from Brazil in this study, and blaSHV-18, which has never been described in Brazil before. This fact highlights the importance of controlling the use of antibiotics in animal production to reduce environmental sources of resistance genes. [ABSTRACT FROM AUTHOR]

Escherichia coli carrying bla CTX–M–1 mediating resistance to extended-spectrum cephalosporins was recently described as a new genotype in Norwegian broiler production. The aim of this study was to characterize these isolates (n = 31) in order to determine whether the emergence of the genotype was caused by clonal expansion or horizontal dissemination of bla CTX–M–1-carrying plasmids. All included isolates were subjected to whole genome sequencing. Plasmid transferability was determined by conjugation, and plasmid replicons in the transconjugants were described using PCR-based replicon typing. Plasmid sizes were determined using S1 nuclease digestion. Plasmids in a subset of strains were reconstructed and compared to plasmids from broiler production in other European countries. The isolates belonged to nine different sequence types (STs), with the largest group being ST57 (n = 12). The vast majority of bla CTX–M–1-carrying plasmids were conjugative. All transconjugants were positive for the IncI1-Iγ replicon, and several also harbored the IncFIB replicon. Highly similar plasmids were present in different E. coli STs. Additionally, high similarity to previously published plasmids was detected. A reconstructed plasmid from an ST57 isolate harbored both IncI1-Iγ and IncFIB replicons and was considered to be co-integrated. The presence of one large plasmid was confirmed by S1 nuclease digestion. Our results show that dissemination of bla CTX–M–1 in Norwegian broiler production is due to both clonal expansion and horizontal transfer of plasmids carrying bla CTX–M–1. The bla CTX–M–1/IncI1-Iγ plasmids grouped into two main lineages, namely clonal complex (CC)-3 and CC-7. The genetic diversity at both strain and plasmid level indicates multiple introductions to Norway. We also show that the bla CTX–M–1 plasmids circulating in Norwegian broiler production are highly similar to plasmids previously described in other countries. [ABSTRACT FROM AUTHOR]

This study aims to investigate and compare the complete nucleotide sequences of the multidrug resistance plasmids pVb0267 and pVb0499, which were recovered from foodborne Vibrio parahaemolyticus isolates, and analyze the genetic environment of blaCTX–M–55 to provide insight into the dissemination mechanisms of this resistance element. Analysis of the sequences of plasmids pVb0267 (166,467 bp) and pVb0499 (192,739 bp) revealed that the backbones of these two plasmids exhibited a high degree of similarity with pR148, a recognized type 1a IncC plasmid recovered from Aeromonas hydrophila (99% identity). The resistance genes, found in both plasmids, included qacH, aadB, arr2, blaOXA–10, aadA1, sul1, tet(A), and blaCTX–M–55, which were mostly arranged in a specific region designated ARI-A. Plasmid pVb0499 was found to possess a larger size of ARI-A than pVb0267, which lacked a mer determination region, a qnr A segment, an aacC3 gene and several mobility-encoding genes. Comparative analysis of resistance island (RI) of these plasmids and others revealed the potential evolution route of these RI sequences. In conclusion, plasmids harboring the blaCTX–M–55 gene has been recovered in Vibrio parahaemolyticus strains of food origin. It is alarming to find that IncC plasmids harboring resistance islands are disseminating in aquatic bacterial strains. The continuous evolution of resistance genes in conjugative plasmid in aquatic bacteria could be due to bacterial adaption to aquaculture environment, where antibiotics were increasingly used.

Objectives: There are few studies addressing the impact of cephalosporin and quinolone resistance on hospital length of stay and mortality in spontaneous bacterial peritonitis (SBP). We aim to describe the shifting epidemiology of SBP at our institution and its impact on clinical outcomes.Methods: We performed a single-center retrospective cohort study of all cases of SBP from 2005 to 2015 at a transplant center. Cases were identified using hospital billing data. Patient data were confirmed using the electronic medical record. Univariate and multivariate logistic regression and Cox proportional hazards models were used to identify factors that were associated with prolonged hospital length of stay and reduced survival. Culture-positive cases (N = 56) were compared to culture-negative cases (N = 104). Subpopulation analysis of the culture-positive cases compared ceftriaxone-resistant (N = 25) to ceftriaxone-susceptible (N = 31) cases.Results: We identified 160 cases of SBP (56 culture positive and 104 culture negative; 21 nosocomial, 79 hospital associated, and 60 community acquired). Forty-five percent (N = 25 total, 13 hospital associated and 6 nosocomial) of bacterial isolates were resistant to ceftriaxone, with 37.5% (N = 21) being gram positive, including 8 methicillin-resistant staphylococcus and 6 vancomycin-resistant enterococcus. Multivariate analysis identified hospital-associated SBP, age, alcoholic cirrhosis, and MELD-Na score as variables associated with worse survival (P < 0.05), with a trend toward worse survival in culture-positive cases (P = 0.123). Only MELD-Na was associated with prolonged length of stay.Conclusions: The burden of resistant pathogens causing SBP is significant, notably in hospital-associated SBP. Culture-positive SBP may represent a higher risk group compared to culture-negative SBP. [ABSTRACT FROM AUTHOR]

Ｏｂｊｅｃｔｉｖｅ Ｔｏ ｉｎｖｅｓｔｉｇａｔｅ ｔｈｅ ｐｒｅｄｉｃｔｉｖｅ ｆａｃｔｏｒｓ ｆｏｒ ｔｈｉｒｄ － ｇｅｎｅｒａｔｉｏｎ ｃｅｐｈａｌｏｓｐｏｒｉｎ － ｒｅｓｉｓｔａｎｔ ｓｐｏｎｔａｎｅｏｕｓ ｂａｃｔｅｒｉａｌ ｐｅｒｉｔｏｎｉｔｉｓ （ＳＢＰ）． Ｍｅｔｈｏｄｓ Ａ ｒｅｔｒｏｓｐｅｃｔｉｖｅ ａｎａｌｙｓｉｓ ｗａｓ ｐｅｒｆｏｒｍｅｄ ｆｏｒ ｔｈｅ ｃｌｉｎｉｃａｌ ｄａｔａ ｏｆ ２０６ ｐａｔｉｅｎｔｓ ｗｉｔｈ ｌｉｖｅｒ ｃｉｒｒｈｏｓｉｓ ｗｈｏ ｗｅｒｅ ｈｏｓｐｉｔａｌｉｚｅｄ ｉｎ ｔｈｅ Ｎｉｎｔｈ Ｈｏｓｐｉｔａｌ ｏｆ Ｎａｎｃｈａｎｇ ｆｒｏｍ Ｊａｎｕａｒｙ ２０１０ ｔｏ Ｄｅｃｅｍｂｅｒ ２０１８，ａｎｄ ａｌｌ ｐａｔｉｅｎｔｓ ｈａｄ ＳＢＰ ｗｉｔｈ ｐｏｓｉｔｉｖｅ ｂａｃｔｅｒｉａ ｂａｓｅｄ ｏｎ ａｓｃｉｔｅｓ ｃｕｌ ｔｕｒｅ． Ａｃｃｏｒｄｉｎｇ ｔｏ ｄｒｕｇ ｓｕｓｃｅｐｔｉｂｉｌｉｔｙ ｒｅｓｕｌｔｓ，ｔｈｅ ｐａｔｉｅｎｔｓ ｗｅｒｅ ｄｉｖｉｄｅｄ ｉｎｔｏ ｔｈｉｒｄ － ｇｅｎｅｒａｔｉｏｎ ｃｅｐｈａｌｏｓｐｏｒｉｎ － ｒｅｓｉｓｔａｎｔ ＳＢＰ ｇｒｏｕｐ （１０１ ｐａ ｔｉｅｎｔｓ ｗｉｔｈ ｔｈｉｒｄ － ｇｅｎｅｒａｔｉｏｎ ｃｅｐｈａｌｏｓｐｏｒｉｎ － ｒｅｓｉｓｔａｎｔ ｐａｔｈｏｇｅｎｉｃ ｂａｃｔｅｒｉａ ｉｎ ａｓｃｉｔｅｓ）ａｎｄ ｃｏｎｔｒｏｌ ｇｒｏｕｐ （１０５ ｐａｔｉｅｎｔｓ ｗｉｔｈ ｐａｔｈｏｇｅｎｉｃ ｂａｃｔｅ ｒｉａ ｓｅｎｓｉｔｉｖｅ ｔｏ ｔｈｉｒｄ － ｇｅｎｅｒａｔｉｏｎ ｃｅｐｈａｌｏｓｐｏｒｉｎ）． Ｅｌｅｃｔｒｏｎｉｃ ｍｅｄｉｃａｌ ｒｅｃｏｒｄｓ ｗｅｒｅ ｒｅｖｉｅｗｅｄ ｔｏ ｃｏｌｌｅｃｔ ｒｅｌａｔｅｄ ｉｎｆｏｒｍａｔｉｏｎ． Ｔｈｅ ｔ － ｔｅｓｔ ｗａｓ ｕｓｅｄ ｆｏｒ ｃｏｍｐａｒｉｓｏｎ ｏｆ ｎｏｒｍａｌｌｙ ｄｉｓｔｒｉｂｕｔｅｄ ｃｏｎｔｉｎｕｏｕｓ ｄａｔａ ｂｅｔｗｅｅｎ ｇｒｏｕｐｓ，ａｎｄ ｔｈｅ Ｍａｎｎ － Ｗｈｉｔｎｅｙ Ｕ ｔｅｓｔ ｗａｓ ｕｓｅｄ ｆｏｒ ｃｏｍｐａｒｉｓｏｎ ｏｆ ｄａｔａ ｗｉｔｈ ｓｋｅｗｅｄ ｄｉｓｔｒｉｂｕｔｉｏｎ ｂｅｔｗｅｅｎ ｇｒｏｕｐｓ． Ｔｈｅ ｃｈｉ － ｓｑｕａｒｅ ｔｅｓｔ ｏｒ ｔｈｅ Ｆｉｓｈｅｒ’ｓ ｅｘａｃｔ ｔｅｓｔ ｗａｓ ｕｓｅｄ ｆｏｒ ｃｏｍｐａｒｉｓｏｎ ｏｆ ｃａｔｅｇｏｒｉｃａｌ ｄａｔａ ｂｅｔｗｅｅｎ ｇｒｏｕｐｓ． Ａ ｄｉｃｈｏｔｏｍｏｕｓ ｌｏｇｉｓｔｉｃ ｒｅｇｒｅｓｓｉｏｎ ａｎａｌｙｓｉｓ ｗａｓ ｕｓｅｄ ｆｏｒ ｍｕｌｔｉｖａｒｉａｔｅ ａｎａｌｙｓｉｓ，ａｎｄ ｔｈｅ Ｆｏｒｗａｒｄ：ＬＲ ｍｅｔｈｏｄ ｗａｓ ｕｓｅｄ ｆｏｒ ｔｈｅ ｓｃｒｅｅｎｉｎｇ ｏｆ ｉｎｄｅｐｅｎｄｅｎｔ ｖａｒｉａｂｌｅｓ． Ｒｅｓｕｌｔｓ Ｔｈｅｒｅ ｗａｓ ａ ｓｉｇｎｉｆｉｃａｎｔ ｄｉｆｆｅｒｅｎｃｅ ｉｎ ｔｈｅ ｃｏｍｐｏｓｉｔｉｏｎ ｏｆ ｐａｔｈｏｇｅｎｉｃ ｂａｃｔｅｒｉａ ｂｅｔｗｅｅｎ ｔｈｅ ｔｗｏ ｇｒｏｕｐｓ （Ｐ ＜ ０． ００１）． Ｔｈｅ ｕｎｉｖａｒｉａｔｅ ａｎａｌｙｓｉｓ ｓｈｏｗｅｄ ｔｈａｔ ａ ｈｉｓｔｏｒｙ ｏｆ ｂｒｏａｄ － ｓｐｅｃｔｒｕｍ ａｎｔｉｂｉｏｔｉｃ ｅｘｐｏｓｕｒｅ ｉｎ ｔｈｅ ｐａｓｔ ｔｈｒｅｅ ｍｏｎｔｈｓ （χ２ ＝ １２． ３５１，Ｐ ＜ ０ ００１），ｎｏｎ － ｆｉｒｓｔ － ｔｉｍｅ ｏｎｓｅｔ ｏｆ ＳＢＰ （χ２ ＝１４． ４２７，Ｐ ＜０． ００１），ｂｌｏｏｄ ｃｒｅａｔｉｎｉｎｅ （χ２ ＝ － ２． ５３７，Ｐ ＝ ０． ０１１），ａｎｄ ｂｌｏｏｄ ｂｉｃａｒｂｏｎａｔｅ （χ２ ＝ －４． ５９２，Ｐ ＜０． ００１）ｗｅｒｅ ｃａｎｄｉｄａｔｅ ｐｒｅｄｉｃｔｉｖｅ ｆａｃｔｏｒｓ ｗｉｔｈ ｓｔａｔｉｓｔｉｃａｌ ｓｉｇｎｉｆｉｃａｎｃｅ ｂｅｔｗｅｅｎ ｔｈｅ ｔｗｏ ｇｒｏｕｐｓ，ａｎｄ ｆｕｒｔｈｅｒ ｍｕｌｔｉｖａｒｉａｔｅ ａｎａｌｙｓｉｓ ｓｈｏｗｅｄ ｔｈａｔ ａ ｈｉｓｔｏｒｙ ｏｆ ｂｒｏａｄ － ｓｐｅｃｔｒｕｍ ａｎｔｉｂｉｏｔｉｃ ｅｘｐｏｓｕｒｅ ｉｎ ｔｈｅ ｐａｓｔ ｔｈｒｅｅ ｍｏｎｔｈｓ （ｏｄｄｓ ｒａｔｉｏ ［ＯＲ］＝２． ３７６，９５％ ｃｏｎｆｉｄｅｎｃｅ ｉｎｔｅｒｖａｌ ［ＣＩ］：１． ００９ －５． ５９８，Ｐ ＝ ０． ０４８），ｎｏｎ － ｆｉｒｓｔ － ｔｉｍｅ ｏｎｓｅｔ ｏｆ ＳＢＰ （ＯＲ ＝ ２． ８４１，９５％ ＣＩ：１． １３３ － ７． １２２，Ｐ ＝ ０． ０２６），ａｎｄ ｂｌｏｏｄ ｂｉｃａｒｂｏｎａｔｅ （ＯＲ ＝０． ８９２，９５％ ＣＩ：０． ８１８ －０． ９７３，Ｐ ＝０． ０１０）ｈａｄ ａｎ ｉｎｄｅｐｅｎｄｅｎｔ ｐｒｅｄｉｃｔｉｖｅ ｖａｌｕｅ ｆｏｒ ｔｈｉｒｄ － ｇｅｎｅｒａｔｉｏｎ ｃｅｐｈａｌｏ ｓｐｏｒｉｎ － ｒｅｓｉｓｔａｎｔ ＳＢＰ． Ｃｏｎｃｌｕｓｉｏｎ Ａ ｈｉｓｔｏｒｙ ｏｆ ｂｒｏａｄ － ｓｐｅｃｔｒｕｍ ａｎｔｉｂｉｏｔｉｃ ｅｘｐｏｓｕｒｅ ｉｎ ｔｈｅ ｐａｓｔ ｔｈｒｅｅ ｍｏｎｔｈｓ，ｎｏｎ － ｆｉｒｓｔ － ｔｉｍｅ ｏｎｓｅｔ ｏｆ ＳＢＰ，ａｎｄ ａ ｌｏｗ ｌｅｖｅｌ ｏｆ ｂｌｏｏｄ ｂｉｃａｒｂｏｎａｔｅ ａｒｅ ｉｎｄｅｐｅｎｄｅｎｔ ｐｒｅｄｉｃｔｉｖｅ ｆａｃｔｏｒｓ ｆｏｒ ｔｈｉｒｄ － ｇｅｎｅｒａｔｉｏｎ ｃｅｐｈａｌｏｓｐｏｒｉｎ － ｒｅｓｉｓｔａｎｔ ＳＢＰ，ａｎｄ ｔｈｉｒｄ － ｇｅｎｅｒａｔｉｏｎ ｃｅｐｈａｌｏｓｐｏｒｉｎｓ ｓｈｏｕｌｄ ｂｅ ｕｓｅｄ ｗｉｔｈ ｃａｕｔｉｏｎ ｉｎ ＳＢＰ ｐａｔｉｅｎｔｓ ｗｉｔｈ ｔｈｅｓｅ ｆｅａｔｕｒｅｓ． [ABSTRACT FROM AUTHOR]

This study aims to investigate and compare the complete nucleotide sequences of the multidrug resistance plasmids pVb0267 and pVb0499, which were recovered from foodborne Vibrio parahaemolyticus isolates, and analyze the genetic environment of blaCTX–M–55 to provide insight into the dissemination mechanisms of this resistance element. Analysis of the sequences of plasmids pVb0267 (166,467 bp) and pVb0499 (192,739 bp) revealed that the backbones of these two plasmids exhibited a high degree of similarity with pR148, a recognized type 1a IncC plasmid recovered from Aeromonas hydrophila (99% identity). The resistance genes, found in both plasmids, included qacH, aadB, arr2, bla OXA–10 , aadA1, sul1, tet (A), and bla CTX–M–55, which were mostly arranged in a specific region designated ARI-A. Plasmid pVb0499 was found to possess a larger size of ARI-A than pVb0267, which lacked a mer determination region, a qnr A segment, an aacC3 gene and several mobility-encoding genes. Comparative analysis of resistance island (RI) of these plasmids and others revealed the potential evolution route of these RI sequences. In conclusion, plasmids harboring the bla CTX–M–55 gene has been recovered in Vibrio parahaemolyticus strains of food origin. It is alarming to find that IncC plasmids harboring resistance islands are disseminating in aquatic bacterial strains. The continuous evolution of resistance genes in conjugative plasmid in aquatic bacteria could be due to bacterial adaption to aquaculture environment, where antibiotics were increasingly used. [ABSTRACT FROM AUTHOR]

Extensively drug-resistant (XDR) Salmonella Typhi has been reported in Sindh province of Pakistan since 2016. The potential for further spread is of serious concern as remaining treatment options are severely limited. We report the phenotypic and genotypic characterization of 27 XDR S. Typhi isolated from patients attending Jinnah Hospital, Lahore, Pakistan. Isolates were identified by biochemical profiling; antimicrobial susceptibility was determined by a modified Kirby–Bauer method. These findings were confirmed using Illumina whole genome nucleotide sequence data. All sequences were compared to the outbreak strain from Southern Pakistan and typed using the S. Typhi genotyping scheme. All isolates were confirmed by a sequence analysis to harbor an IncY plasmid and the CTX-M-15 ceftriaxone resistance determinant. All isolates were of the same genotypic background as the outbreak strain from Sindh province. We report the first emergence of XDR S. Typhi in Punjab province of Pakistan confirmed by whole genome sequencing.

Introduction: Septicaemia is one of the significant causes of morbidity and mortality in Intensive Care Units (ICUs). The rate of antimicrobial resistance in ICU is very high compared to general hospital setting. Aim: To enumerate common bacterial pathogens causing sepsis and to identify their antimicrobial susceptibility pattern. Materials and Methods: This was a retrospective descriptive study done in patients with sepsis during January 2016 to December 2017. The Institutional Ethical Committee clearance was obtained. Data were collected from inpatient case files regarding clinical history, laboratory parameters with special reference to causative organisms and antibiotic sensitivity pattern. Data were entered in Microsoft Excel sheet and analysed using strata 14.0. Results: Among 216 subjects of sepsis admitted to ICU during study period, 130 (60.1%) were males, with mean age of 52.83 year (±16.6 SD). Pneumonia (31.94%) was the major cause of sepsis followed by urosepsis. Gram negative organisms were the major cause of sepsis accounting for 76.25% of organisms isolated. Escherichia coli was the most common organism isolated in urine (65.9%) and blood cultures (32%). All Gram negative bacteria had high level of resistance to Amoxicillin Clavulunic Acid (Amoxyclav) (85.9%), ampicillin sulbactum (66.7%) and third generation cephalosporins (70%). Conclusion: Gram negative organisms were the principal causes of septicaemia. Cephalosporin resistance was more than 70%. Acinetobacter species was resistant to most antibiotics. The knowledge of bacterial profile of sepsis and antibiotic susceptibility pattern not only helps in improving outcome but also prevents emergence of drug resistance strains.

Antimicrobial resistance was tested in Escherichia coli isolated from feces ( n  = 660) of red deer, roe deer, fallow deer, European bison, and wild boar shot in regional forests in Poland during two winter hunting seasons. Indicator E. coli ( n  = 542) was resistant against 11 of 14 tested compounds, mostly sulfamethoxazole, streptomycin, ampicillin, trimethoprim, and tetracycline (1.3–6.6% range). No significant differences were observed between boar and ruminant isolates. Most of deer and bison isolates showed no resistance. Selective screening of wildlife samples revealed 1.7% prevalence of cephalosporin-resistant E. coli found mostly in wild boars. They produced extended-spectrum beta-lactamases ( bla CTX-M-1, bla CTX-M-15) and plasmid–mediated AmpC-type cephalosporinase ( bla CMY-2). The majority of the isolates originated from boars shot in a narrow time frame and space; therefore, common antimicrobial selection pressure in the environment was assumed. Three E. coli isolates carried plasmid–mediated quinolone resistance genes ( qnrS1/S3 ). No transferable colistin resistance mechanisms were found in two resistant E. coli. Transferability of resistance was proved in a single pAmpC-positive isolate carrying IncI1-alpha 95 kb plasmid. No cephalosporin-resistant E. coli harbored pathogenicity markers; therefore, they might be considered a vector of resistance determinants, but not a pathogen themselves. [ABSTRACT FROM AUTHOR]

Objectives: To identify the genetic basis of resistance as well as to better understand the epidemiology of a recent surge in azithromycin-resistant Neisseria gonorrhoeae in New South Wales, Australia.Methods: Azithromycin-resistant N. gonorrhoeae isolates (n = 118) collected from 107 males, 10 females and 1 transsexual between January and July 2017 were genotyped using a previously described iPLEX method. The results were compared with phenotypic resistance profiles and available patient data.Results: The iPLEX results revealed 10 different N. gonorrhoeae genotypes (designated AZI-G1 to AZI-G10) of which three were responsible for the majority of infections; AZI-G10 (74.6%, 88 isolates; 87 males and 1 transsexual), AZI-G4 (11.0%, 13 isolates; 7 males and 6 females) and AZI-G7 (6.8%, 8 isolates; 7 males and 1 female). The observed resistance was attributable to one of two different azithromycin resistance mechanisms; the 23S rRNA C2611T mutation was identified in 24% of isolates, whereas the majority of resistance (76%) was associated with a meningococcal-type mtrR variant. Additionally, one isolate was found to harbour both the 23S rRNA C2611T mutation and a type XXXIV mosaic penA sequence associated with cephalosporin resistance.Conclusions: These data indicate outbreaks of azithromycin-resistant gonococci amongst networks of MSM and heterosexuals in New South Wales. The results also provide further evidence that azithromycin may soon be an ineffective treatment option for gonococcal infection and highlight the urgent need to explore alternative therapies. [ABSTRACT FROM AUTHOR]

Introduction: Septicaemia is one of the significant causes of morbidity and mortality in Intensive Care Units (ICUs). The rate of antimicrobial resistance in ICU is very high compared to general hospital setting. Aim: To enumerate common bacterial pathogens causing sepsis and to identify their antimicrobial susceptibility pattern. Materials and Methods: This was a retrospective descriptive study done in patients with sepsis during January 2016 to December 2017. The Institutional Ethical Committee clearance was obtained. Data were collected from inpatient case files regarding clinical history, laboratory parameters with special reference to causative organisms and antibiotic sensitivity pattern. Data were entered in Microsoft Excel sheet and analysed using strata 14.0. Results: Among 216 subjects of sepsis admitted to ICU during study period, 130 (60.1%) were males, with mean age of 52.83 year (±16.6 SD). Pneumonia (31.94%) was the major cause of sepsis followed by urosepsis. Gram negative organisms were the major cause of sepsis accounting for 76.25% of organisms isolated. Escherichia coli was the most common organism isolated in urine (65.9%) and blood cultures (32%). All Gram negative bacteria had high level of resistance to Amoxicillin Clavulunic Acid (Amoxyclav) (85.9%), ampicillin sulbactum (66.7%) and third generation cephalosporins (70%). Conclusion: Gram negative organisms were the principal causes of septicaemia. Cephalosporin resistance was more than 70%. Acinetobacter species was resistant to most antibiotics. The knowledge of bacterial profile of sepsis and antibiotic susceptibility pattern not only helps in improving outcome but also prevents emergence of drug resistance strains. [ABSTRACT FROM AUTHOR]

Klebsiella spp. isolates from community-acquired infections were characterized. A total of 39 Klebsiella spp. isolates were obtained from outpatients at four rural hospitals in Mexico (2013–2014). The biochemical tests identified all as being K. pneumoniae . The molecular multiplex-PCR test identified 36 (92.4%) K. pneumoniae isolates and one (2.5%) K. variicola isolate, and phylogenetic analysis of the rpoB gene identified two isolates (5.1%) belonging to K. quasipneumoniae subsp. quasipneumoniae and K. quasivariicola . The last one was confirmed by phylogenetic analysis of six-loci concatenated genes. Mostly the isolates were multidrug resistant; however, a minority were extended-spectrum β-lactamase producing (10.2%). The extended-spectrum β-lactamase CTX-M-15 gene was identified in these isolates. Analysis of biofilm production and the hypermucoviscosity phenotype showed a total of 35 (92.3%) and seven (17.9%) of the isolates were positive for these phenotypes respectively. The K2 (4/39, 10.2%), K5 (2/39, 5.1%) and K54 (1/39, 2.5%) serotypes were identified in seven (17.9%) of the isolates, and only 28.5% (2/7) hypermucoviscous isolates were positive for the K2 and K5 serotypes. In general, the sequence type (ST) analysis and phylogenetic analysis of seven multilocus sequence typing loci were heterogeneous; however, ST29 was the most prevalent ST in the analysed isolates, accounting for 19% (4/21) of the total isolates. Two of the four ST29 isolates had the hypermucoviscosity phenotype. The virulence factors for fimbriae were the most prevalent, followed by siderophores. Community-acquired infections are caused by various species from Klebsiella genus, with different profiles of antibiotic resistance and heterogeneous virulence factors. [ABSTRACT FROM AUTHOR]

Objective: Antimicrobial-resistant bacteria may be transmitted between farm workers and livestock. This study aimed to determine and compare the prevalence and the genetic determinants of cefotaxime-resistant and ESBL-producing Escherichia coli in faecal isolates from workers and pigs at 100 farms in northern Vietnam.Methods: Farmers were interviewed about antimicrobial usage in livestock. Escherichia coli isolated on MacConkey agar containing 2 mg/l of cefotaxime (CTX) were tested for susceptibility to different cephalosporins by disc diffusion and screened for occurrence of ESBL-encoding genes by PCR.Results: Antimicrobial usage was widespread and included classes regarded of critical or high importance in human medicine. Dosages were 0.5-2 times higher than recommended, and antimicrobials were often administered right until slaughter. Prevalence of CTX-resistant E. coli was 86% in farm workers and 89% in pigs. In 76% of farms, CTX-resistant E. coli were shared by pigs and farm workers. ESBL-producing E. coli were detected from pigs and workers at 66 and 69 farms, respectively. The ESBL phenotype was mainly mediated by CTX-M and to a lesser extent by TEM. Occurrence of blaCTX-M was similar in E. coli from pigs (66.7%) and humans (68.5%).Conclusion: The high occurrence of ESBL-producing E. coli in pig farmers and pigs could present a risk for spillover of these bacteria from pig farms into the community. Genomic studies are needed to elucidate reservoirs and transmission routes of ESBL-producing E. coli at livestock farms. [ABSTRACT FROM AUTHOR]

Abstract: Aims: β‐lactamase inhibitor resistance (BLIR) among the uropathogenic Escherichia coli (UPEC) minimizes treatment options. This study aimed to identify inhibitor‐resistant TEM (IRT) β‐lactamase that impart BLIR phenotype and explore non‐β‐lactams as alternative therapeutics. Methods and Results: Thirty BLIR UPEC isolates were detected by Kirby–Bauer disc diffusion technique using β‐lactam–β‐lactamase inhibitor combination. Conjugal transfer of BLIR was successful from 17 isolates. PCR and sequencing of the TEM β‐lactamases from the transconjugants indicated 14 TEM‐84 (IRT) and three novel IRT variants (pUE184TEM, pUE203TEM, pUE210TEM). Three‐dimensional models of the latter were predicted and validated. Molecular docking of selected non‐β‐lactams (morin, catechin, naringenin triacetate) with the variants using AutoDock 4.2 showed comparable docking scores with significant hydrogen bond and hydrophobic interactions. Molecular dynamics simulation study confirmed stability of the non‐β‐lactams inside the catalytic pocket of the enzymes. Moreover, all three non‐β‐lactams were found to inhibit the purified TEM β‐lactamase variants in vitro. Microbroth dilution method indicated naringenin triacetate 64 μg ml−1 in combination with ceftazidime (CAZ) 30 μg ml−1 to be most effective against the BLIR transconjugants. Conclusions: BLIR phenotypes were primarily attributed to the production of IRT β‐lactamases. Administration of the non‐β‐lactams with CAZ demonstrated an alternative therapeutic strategy against the IRT β‐lactamase producers. Significance and Impact of the Study: This study indicates high risk of transmission of IRT β‐lactamases and suggests β‐lactam–non‐β‐lactam combination therapy to combat BLIR. [ABSTRACT FROM AUTHOR]

The intestinal flora of healthy broilers can contain Escherichia coli resistant to extended spectrum cephalosporins (ESC) and fluoroquinolones (FQ), representing a possible public health problem. We investigated the clonal epidemiology of E. coli with reduced susceptibility to ESC or FQ in broilers in three Nordic countries interconnected by a common source of breeding animals. Isolates (n = 319 and n = 132 non-wild type for ESC and FQ, respectively) from Norwegian, Swedish and Icelandic production originated mainly from the intestinal flora of broilers at the age of 20–35 days. Genetic relationships were investigated by ten loci multilocus variable number tandem repeat analyses (MLVA) and representative isolates of inter-Nordic clusters were subjected to multilocus sequence typing (MLST). Antimicrobial susceptibility data based on minimum inhibitory concentrations was compiled. Approximately one third of the ESC non-wild type isolates, including isolates from all three countries, clustered together. These isolates belonged to sequence type (ST) 38 and contained bla CMY-2 . The FQ non-wild type isolates were more genetically diverse, but related isolates occurred in more than one country. MLST typing showed clusters belonging to ST10, ST355, ST349, ST665 and ST93. Our study demonstrated inter-Nordic distribution of E. coli ST38 with bla CMY-2, suggesting clonal proliferation as a contributing factor for spread of ESC resistance in the broiler production. The international trade in breeding material may explain introduction of resistant E. coli . The reason for their success and the success of certain clonal lineages in broiler production not exposed to antimicrobial selection pressure is currently unknown. [ABSTRACT FROM AUTHOR]

[Display omitted] • The functional consequences of GpsB phosphorylation in enterococci are unknown. • Phosphorylation does not impact the flexibility of the C-terminal extension of GpsB. • Phosphorylation at GpsB S80 and T84 impairs IreK signaling and cephalosporin resistance. • Phosphorylation at GpsB T133 enables phosphorylation at other GpsB sites. • Multisite phosphorylation modulates the ability of GpsB to activate IreK signaling. Enterococci are normal human commensals and major causes of hospital-acquired infections. Enterococcal infections can be difficult to treat because enterococci harbor intrinsic and acquired antibiotic resistance, such as resistance to cephalosporins. In Enterococcus faecalis , the transmembrane kinase IreK, a member of the bacterial PASTA kinase family, is essential for cephalosporin resistance. The activity of IreK is boosted by the cytoplasmic protein GpsB, which promotes IreK autophosphorylation and signaling to drive cephalosporin resistance. A previous phosphoproteomics study identified eight putative IreK-dependent phosphorylation sites on GpsB, but the functional importance of GpsB phosphorylation was unknown. Here we used genetic and biochemical approaches to define three sites of phosphorylation on GpsB that functionally impact IreK activity and cephalosporin resistance. Phosphorylation at two sites (S80 and T84) serves to impair the ability of GpsB to activate IreK in vivo , suggesting phosphorylation of these sites acts as a means of negative feedback for IreK. The third site of phosphorylation (T133) occurs in a segment of GpsB termed the C-terminal extension that is unique to enterococcal GpsB homologs. The C-terminal extension is highly mobile in solution, suggesting it is largely unstructured, and phosphorylation of T133 appears to enable efficient phosphorylation at S80 / T84. Overall our results are consistent with a model in which multisite phosphorylation of GpsB impairs its ability to activate IreK, thereby diminishing signal transduction through the IreK-dependent pathway and modulating phenotypic cephalosporin resistance. [ABSTRACT FROM AUTHOR]

A genomic analysis of Comamonas testosteroni S44 revealed a gene that encodes a LysR family transcriptional regulator (here named czoR, czo for cefazolin) located upstream of a putative class A β-lactamase encoding gene (here named czoA). A putative DNA-binding motif of the Fe–S cluster assembly regulator IscR was identified in the czoR–czoA intergenic region. Real-time RT-PCR and lacZ fusion expression assays indicated that transcription of czoA and czoR were induced by multiple β-lactams. CzoA expressed in Escherichia coli was shown to contribute to susceptibility to a wide range of β-lactams judged from minimum inhibitory concentrations. In vitro enzymatic assays showed that CzoA hydrolyzed seven β-lactams, including benzylpenicillin, ampicillin, cefalexin, cefazolin, cefuroxime, ceftriaxone, and cefepime. Deletion of either iscR or czoR increased susceptibility to cefalexin and cefazolin, while complemented strains restored their wild-type susceptibility levels. Electrophoretic mobility shift assays (EMSA) demonstrated that CzoR and IscR bind to different sites of the czoR–czoA intergenic region. Precise CzoR- and IscR-binding sites were confirmed via DNase I footprinting or short fragment EMSA. When cefalexin or cefazolin was added to cultures, czoR deletion completely inhibited czoA expression but did not affect iscR transcription, while iscR deletion decreased the expressions of both czoR and czoA. These results reveal that CzoR positively affects the expression of czoA with its own expression upregulated by IscR.

Objective: The aim of this study was to investigate the occurrence and molecular characterization of extended-spectrum β-lactamases (ESBL), plasmid-mediated AmpC β-lactamase (pAmpC) and carbapenemases as well as plasmid-mediated quinolone-resistant (PMQR) among extended-spectrum cephalosporin-resistant (ESC-R) Escherichia coli from dogs in Shaanxi province in China.Methods: A total of 40 ESC-R Escherichia coli selected from 165 Extraintestinal pathogenic E. coli (ExPEC) isolated from dogs were screened and characterized for the genes encoding for the ESBLs, pAmpC, carbapenemases and PMQR genes by PCR and sequencing. Phylogenetic groups, virulence gene profiles and multilocus sequence typing (MLST) were used to investigate the genetic background of the ESC-R E. coli isolates. Results: Among 40 ESC-R E. coli, the predominant β-lactamase gene was blaCTX-Ms (n=35), and followed by blaTEM-1 (n=31), blaSHV-12 (n=14), blaOXA-48 (n=8), blaTEM-30 (n=4), blaCMY-2 (n=3) and blaDHA-1 (n=2). The most common specific blaCTX-M gene subtype was blaCTX-M-15 (n=31), and followed by blaCTX-M-123 (n=14), blaCTX-M-1 (n=10), blaCTX-M-14 (n=10) and blaCTX-M-9 (n=7). PMQR genes were detected in 32 (80%) isolates, and the predominant PMQR gene was aac(6')-Ib-cr (n=26), followed by qnrS (n=12), qnrD (n=9), qnrB (n=8), qepA (n=4), and all PMQR genes were detected in co-existence with β-lactamase genes. traT (n=34) and fimH (n=32) were the most prevalent virulence genes, and virulence genes fimH, iutA, fyuA, malX, iha and sat were more prevalent in phylogenetic group B2. The 40 ESC-R isolates analyzed were assigned to 22 sequence types (STs), and the clonal lineages ST131 (n=10) and ST10 (n=9) were the predominant STs. Conclusion: High prevalence of β-lantamases and PMQR genes were detected among ESC-R E. coli from companion animals. This is also the first description of the co-existence of six β-lantamase genes and five PMQR genes in one E. coli isolate. Moreover, ten ST131 clones harboring CTX-M-15 were detected.

CMY-2 ß-lactamase is an important cause of ß-lactam resistance in Enterobacteriaceae and constitutes the most widespread pAmpC. Although CMY-2 has been previously recognized in our region, the real prevalence and epidemiology of this resistance marker was uncertain. During August-October 2009, we conducted a multicenter, prospective study to determine pAmpC prevalence and to characterize CMY-2 producing Escherichia coli associated plasmids. Plasmid-encoded AmpC prevalence was 0.9 % in enterobacteria in this period, being CMY- 2 prevalent and to a lesser extent DHA. Molecular typing of CMY-2- producing Escherichia coli isolates showed several lineages. Moreover, replicon typing of cmy-2- containing plasmids displayed a broad diversity in Inc/cmy- 2 links. Therefore, association of cmy-2 with specific transposon elements may be responsible for the spread of this resistance marker in Enterobacteriaceae.La ß-lactamasa de tipo AmpC de codificación plasmídica CMY-2 es la de mayor diseminación a nivel mundial en Enterobacteriaceae. Esta ha sido comunicada esporádicamente en nuestro país. Entre agosto y octubre de 2009 se llevó a cabo un estudio prospectivo y multicéntrico con el objetivo de determinar la prevalencia de pAmpC en nuestro medio y de caracterizar a los microorganismos productores y a los plásmidos portadores de estos marcadores de resistencia. La prevalencia de pAmpC plasmídicas en enterobacterias en este período fue de 0,9 %. La ß-lactamasa CMY-2 fue la enzima prevalente y, en menor medida, la DHA. La tipificación molecular de los aislamientos de Escherichia coli productores de CMY-2 mostró la presencia de distintos linajes, y los plásmidos portadores de cmy-2 pertenecieron a una amplia diversidad de grupos de incompatibilidad. Se determinó la asociación corriente arriba de cmy-2 con ISEcp1, el cual podría ser responsable de la amplia diseminación de este marcador de resistencia en Enterobacteriaceae.

Gonorrhea, a disease of public health importance, not only leads to high incidence of acute infections and complications but also plays a major role in facilitating human immunodeficiency virus (HIV) acquisition and transmission. One of the major public health needs for gonorrhea control is appropriate, effective treatment. However, treatment options for gonorrhea are diminishing as Neisseria gonorrhoeae have developed resistance to several antimicrobial drugs such as sulfonamides, penicillin, tetracyclines and quinolones. Antimicrobial resistance (AMR) surveillance of N. gonorrhoeae helps establish and maintain the efficacy of standard treatment regimens. AMR surveillance should be continuous to reveal the emergence of new resistant strains, monitor the changing patterns of resistance, and be able to update treatment recommendations so as to assist in disease control. Current treatment guidelines recommend the use of single dose injectable or oral cephalosporins. The emergence and spread of cephalosporin resistant and multi drug resistant N. gonorrhoeae strains, represents a worrying trend that requires monitoring and investigation. Routine clinical laboratories need to be vigilant for the detection of such strains such that strategies for control and prevention could be reviewed and revised from time to time. It will be important to elucidate the genetic mechanisms responsible for decreased susceptibility and future resistance. There is also an urgent need for research of safe, alternative anti-gonococcal compounds that can be administered orally and have effective potency, allowing high therapeutic efficacy (greater than 95.0% cure rate).

Background Prophylactic antibiotics significantly reduce prosthetic joint infection ( PJI) rates after hip and knee arthroplasty. However, rising antibiotic resistance has raised concerns over the adequacy of conventional prophylaxis. This study aimed to identify organisms causing PJIs in hip and knee arthroplasty secondary to perioperative contamination and their susceptibility to current prophylactic antibiotics. Methods We performed a retrospective audit of 4009 primary hip and knee arthroplasties (1852 hips and 2157 knees) at three tertiary referral hospitals. PJIs were identified according to the Infectious Diseases Society of America definition, and patients were followed-up for 2 years. For patients with confirmed PJIs, causative bacteria and their antibiotic susceptibilities were identified. Results Thirty-five PJI cases were identified (13 hips and 22 knees). The overall definite PJI rate was 0.87% (0.7% for hips, 1.0% for knees). Ninety-six percent of patients with PJI received cefazolin prophylaxis. Culture information was available for 30 cases. The most common infecting organisms were coagulase-negative staphylococci ( CoNS), causing 35% of infections. Ninety-two percent of CoNS strains were cefazolin-resistant. Twenty-five percent of patients were infected with Staphylococcus aureus, 9.1% of which were methicillin-resistant. Overall, 53% of infecting organisms were cefazolin-resistant. Conclusions The majority of bacteria causing early PJI are resistant to cefazolin. Whilst many organisms cultured were susceptible to vancomycin, there is currently insufficient evidence to justify its routine use as a prophylactic. However, when treating PJI in the early postoperative period, surgeons should be aware that most organisms will be methicillin-resistant, and the choice of empirical antibiotic treatment should reflect this. [ABSTRACT FROM AUTHOR]

Limited data identify the risk factors for infection with Enterobacteriaceae resistant to third-generation cephalosporins among residents of long-term-care facilities. Using a nested case-control study design, nursing home residents with clinical isolates of Enterobacteriaceae resistant to third-generation cephalosporins were compared to residents with isolates of Enterobacteriaceae susceptible to third-generation cephalosporins. Data were collected on antimicrobial drug exposure 10 weeks before detection of the isolates, facility-level demographics, hygiene facilities, and staffing levels. Logistic regression models were built to adjust for confounding variables. Twenty-seven case-residents were identified and compared to 85 controls. Exposure to any cephalosporin (adjusted odds ratio [OR] 4.0, 95% confidence interval [CI] 1.2 to13.6) and log percentage of residents using gastrostomy tubes within the nursing home (adjusted OR 3.9, 95% CI 1.3 to 12.0) were associated with having a clinical isolate resistant to third-generation cephalosporins.

The clonal composition of Escherichia coli causing extra-intestinal infections includes ST131 and other common uropathogenic clones. Drivers for the spread of these clones and risks for their acquisition have been difficult to define. In this study, molecular epidemiology was combined with clinical data from 182 patients enrolled in a case–control study of community-onset expanded-spectrum cephalosporin-resistant E. coli (ESC-R-EC) in Australia and New Zealand. Genetic analysis included antimicrobial resistance mechanisms, clonality by DiversiLab (rep-PCR) and multilocus sequence typing (MLST), and subtyping of ST131 by identification of polymorphisms in the fimH gene. The clonal composition of expanded-spectrum cephalosporin-susceptible E. coli and ESC-R-EC isolates differed, with six MLST clusters amongst susceptible isolates (median 7 isolates/cluster) and three clusters amongst resistant isolates, including 40 (45%) ST131 isolates. Population estimates indicate that ST131 comprises 8% of all E. coli within our population; the fluoroquinolone-susceptible H41 subclone comprised 4.5% and the H30 subclone comprised 3.5%. The H30 subclone comprised 39% of all ESC-R-EC and 41% of all fluoroquinolone-resistant E. coli within our population. Patients with ST131 were also more likely than those with non-ST131 isolates to present with an upper than lower urinary tract infection (RR = 1.8, 95% CI 1.01–3.1). ST131 and the H30 subclone were predominant amongst ESC-R-EC but were infrequent amongst susceptible isolates where the H41 subclone was more prevalent. Within our population, the proportional contribution of ST131 to fluoroquinolone resistance is comparable with that of other regions. In contrast, the overall burden of ST131 is low by global standards. [ABSTRACT FROM AUTHOR]

Both acquired and intrinsic mechanisms play a crucial role in Pseudomonas aeruginosa antibiotic resistance. Many clinically relevant resistance mechanisms result from changes in gene expression, namely multidrug efflux pump overproduction, AmpC β-lactamase induction or derepression, and inactivation or repression of the carbapenem-specific porin OprD. Changes in gene expression are usually assessed using reverse-transcription quantitative real-time PCR (RT-qPCR) assays. Here, we evaluated label-free Selected Reaction Monitoring (SRM)-based mass spectrometry to directly quantify proteins involved in antibiotic resistance. We evaluated the label-free SRM using a defined set of P. aeruginosa isolates with known resistance mechanisms and compared it with RT-qPCR. Referring to efflux systems, we found a more robust relative quantification of antibiotic resistance mechanisms by SRM than RT-qPCR. The SRM-based approach was applied to a set of clinical P. aeruginosa isolates to detect antibiotic resistance proteins. This multiplexed SRM-based approach is a rapid and reliable method for the simultaneous detection and quantification of resistance mechanisms and we demonstrate its relevance for antibiotic resistance prediction. [ABSTRACT FROM AUTHOR]