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Abstract Fluoroquinolone-resistant (FQs-R) microorganisms causing infectious complications after ultrasound-guided needle biopsy of the prostate (TRUS-BP) have become an important challenge in healthcare settings globally, questioning the continued utility of FQ as the preferred prophylactic agent. This study aimed to characterize molecular mechanisms of resistance on FQs-R E. coli isolated from the enteric microbiota of patients undergoing (TRUS-BP) and to highlight their impact on Minimum Inhibitory Concentrations (MICs). From February 2016 to December 2018, the incidence of rectal carriage of Qs-FQs resistant Enterobacterales detected from rectal swabs of patients before undergoing (TRUS-BP) was 61.06% (80/131) all related to E. coli species. Based on the MICs range of Qs (24–256 mg/L) and FQs (0.24–128 mg/L) breakpoint by EUCAST, we categorized these E. coli isolates into three resistance profiles (I, II, and III) associated with the patterns of chromosomal mutations in the quinolone resistance-determining regions (QRDRs) of gyrA and parC and the plasmid-mediated quinolone resistance encoding genes (PMQRs) detected by PCR-based assay and sequencing; MICs increase in an escalation step according to the co-occurrence of multiple molecular mechanisms. The mutation of the gyrA gene was the most frequent on codons (Ser83Leu/Thr/Tyr/Trp and Asp87Asn); mutation on the parC gene was the least on codons (Ser80Iso/Leu and Glu84 Val/Gly/Lys). PMQRs genes (4 qnrB ,7 qnrS, and one aac(6’)-Ib-cr) were determined within 15% of the isolates. Allelic variation allows us to report earliest the qnrB81 determinant in an E. coli isolate. Among isolates (35%) belonged to the notorious ST131 lineage. The phylogenetic group showed a predominance of B2 group (51, 25%), however (PFGE) revealed a high level of clonal variability. Worrying incidence of FQs-R E. coli isolates in the rectal flora of our local population showed the potential to cause post-infection. FQ resistance is a complex interplay between mutations in the QRDRs and PMQR determinants that impact MICs. The importance of intestinal microbiota as a reservoir of resistant strains and pandemic clones encourages driving mitigation challenges to characterize molecular mechanisms of antimicrobial resistance to adapt prophylactic therapy, control infection, and ensure epidemiological monitoring.

Objective: There is very limited information about OXA-48-producing Klebsiella oxytoca. The aim of this study was to describe the phenotypic and molecular characterization of OXA-48-producing K. oxytoca isolates that caused an outbreak in a hospital in Tunisia. Methods: Nineteen OXA-48-producing K. oxytoca were isolated from 2013 to 2016 in the University Hospital Farhat Hached, Sousse, Tunisia. Antibiotic susceptibility testing was performed by broth microdilution. Carbapenemase activity was investigated using the modified carbapenem inactivation method (mCIM). Phenotypic tests were also carried out to detect extended-spectrum β-lactamases. PCR was used to test for the presence of carbapenemase genes (blaIMP, blaVIM, blaNDM, blaSPM, blaAIM, blaDIM, blaGIM, blaSIM, blaKPC, blaBIC and blaOXA-48). Genetic relatedness among isolates was investigated using rep-PCR. Whole genome sequencing (WGS) was performed in three representative isolates. Results: mCIM was positive in all isolates. None of the isolates presented an ESBL phenotype. All strains were susceptible to cefoxitin, ceftazidime, cefepime, aztreonam, imipenem, meropenem, fluoroquinolones, aminoglycosides and colistin, and resistant to piperacillin-tazobactam, ertapenem, ticarcillin and ampicillin-sulbactam. All isolates presented the blaOXA-48 gene located in a ca. 63 kb IncL plasmid, which carried no additional resistance genes. They belonged to the new ST220. Conclusion: Isolates from this study did not co-express an ESBL, which could complicate their detection in clinical laboratories. As OXA-48 has been mostly reported in K. pneumoniae there is a risk that the production of this enzyme is not suspected in the less common species K. oxytoca. These difficulties could play an important role in the hidden spread of this enzyme.

Abstract Background In Tunisia, country of intermediate endemicity for Hepatitis B virus (HBV) infection, most molecular studies on the virus have been carried out in the North of the country and little is known about other regions. The aim of this study was to determine HBV genotype and subgenotypes in Central-East Tunisia. A total of 217 HBs antigen positive patients were enrolled and determination of genotype was investigated in 130 patients with detectable HBV DNA. HBV genotyping methods were: PCR-RFLP on the pre-S region, a PCR using type-specific primers in the S region (TSP-PCR) and partial sequencing in the pre-S region. Results Three genotypes (D, B and A) were detected by the PCR-RFLP method and two (D and A) with the TSP-PCR method, the concordance between the two methods was 93%. Sequencing and phylogenetic analysis of 32 strains, retrieved the same genotype (D and A) for samples with concordant results and genotype D for samples with discordant results. The sequences of discordant genotypes had a restriction site in the pre-S gene which led to erroneous result by the PCR-RFLP method. Thus, prevalence of genotype D and A was 96% and 4%, respectively. Phylogenetic analysis showed the predominance of two subgenotypes D1 (55%) and D7 (41%). Only one strain clustered with D3 subgenotype (3%). Conclusions Predominance of subgenotype D7 appears to occur in northern regions of Africa with transition to subgenotype D1 in the East of the continent. HBV genetic variability may lead to wrong results in rapid genotyping methods and sequence analysis is needed to clarify atypical results.

The Acidaminococcus genus is a part of the normal flora in gastrointestinal tract. It is a strictly anaerob Gram-negative coccus that is rarely pathogenic. We report the case of a 58-year-old man, who presented to surgery department A of the Charles Nicolle hospital, complaining of a wide inflammatory lesion in the anterior abdominal wall evolving for two weeks. Patient's anamnestic data included smoking, hypertension, and diabetes mellitus with poor compliance. The patient underwent flattening with excision of necrotic tissues and surgical drainage using a DELBET blade. Empirical antibiotic therapy with imipenem 1gx3/d, teicoplanin 400 mg 1 inj x2/d and gentamicin 400 mg 1 inj/d was administered pending bacteriological results. The bacteriological examination of a sample of necrotic tissue, after 72 h of incubation at 37 °C in anaerobic atmosphere, was able to detect a Gram-negative coccus, that the VITEK2 ANC system identified as Actinomyces canis with an accuracy of 80%. Whole genome sequencing was subsequently performed, that identified Acidaminococcus sp. AM33-14BH and demonstrated the following resistance genes: cfxa, tet(X) and tet(Q). An antibiogram for anaerobes was performed showing that the strain was resistant to amoxicillin but sensitive to amoxicillin-clavulanic acid, piperacillin-tazobactam, ertapenem, imipenem, meropenem and rifampin. Patient's condition improved after treatment with imipenem for 2 weeks, followed by oral amoxicillin-clavulanic acid for 16 days. This work highlights the role of molecular biology in the diagnosis of infections caused by anaerobes. Although the Vitek 2 ANC card provides rapid and acceptable identification of the most common anaerobic bacteria, improvements are needed for the identification of bacteria in the genera Acidaminococcus and Actinomyces. [ABSTRACT FROM AUTHOR]

The pandemic spread of multidrug-resistant (MDR) bacteria (i.e., methicillin-resistant Staphylococcus aureus (MRSA), extended-spectrum b-lactamase-producing Enterobacteriaceae (ESBLPE), vancomycin-resistant enterococci, carbapenemase-producing Enterobacteriaceae (CPE), multiresistant Pseudomonas aeruginosa and multiresistant Acinetobacter baumannii) pose a threat to healthcare Worldwide. We found limited data of MDR bacteria in pediatric patients hospitalized in Tunisian tertiary healthcare.The aim of the study is to evaluate the acquisition rate of MDR acquisition during hospitalization and to explore some of the associated risk factors for both carriage and acquisition at the pediatric department, Sahloul University Hospital. During September and October 2016, newly admitted patients were screened, at admission, during care and at discharge. Risk factors for colonization were explored by multivariate analysis. Of 112 newly admitted patients, 8.92% were colonized with at least one MDR. No risk factor was identified at admission. During hospitalization, five newly acquisition MDR (4.9%) were detected and eight (7.84%) at discharge. The specie most frequently detected on admission was Escherichia coli (50%), whereas, on discharge, Escherichia coli and K. pneumoniae were the species most frequently detected (52.7%). The pediatric intensive care unit (PICU) hospitalization, the length of hospital stay (more than 3days) and age under 2 years were identified as risk factor for acquisition of MDR during hospitalization. We identified several independent risk factors for contracting MDR bacteria during hospitalization in a tertiary pediatric department. The incidence of symptomatic MDR Infection among those colonized should be under close surveillance and long-term screening for those children is required. An institutional screening program for MDR especially in PICU might be discussed in regards to cost effectiveness. [ABSTRACT FROM AUTHOR]

The exponential rise of bacterial resistance poses a threat to antibiotic efficacy, with a great impact on public health. This study aims to analyze the correlation between antibiotic consumption and the emergence of bacterial resistance. Conducted retrospectively at Charles Nicolle Hospital in Tunis, Tunisia, from 2010 to 2022, this study was based on STKMED ® software for antibiotic consumption data, hospital administrative records for the number of hospitalization days, and SIRSCAN ® software for bacteriological data. Data processing was performed using Excel ® software version 2019, and analysis was conducted using SPSS23 ® . In 2022, consumption was almost evenly split between the two major "AWaRe" groups, with 49.33% for "Access" and 46.89% for "Watch", and the consumption of the "Reserve" group also increased, accounting for 3.77% of the total. Bacterial resistances, notably carbapenem-resistant Klebsiella pneumoniae , increased. Seventy-four significant correlations were identified, including those between carbapenem consumption and resistance in Escherichia coli and Klebsiella pneumoniae strains. However, no significant correlation was observed with imipenem-resistant Pseudomonas aeruginosa strains. The significant correlations between the emergence of bacterial resistance and antibiotic use, particularly with antibiotics in the "Watch" and "Reserve" groups, underscore the urgent need to continue efforts to combat this threat through rational antibiotic use.

Brucellosis represents a significant global health concern that is endemic in many regions of the world, especially in Maghreb (Tunisia, Morocco and Algeria). In Tunisia the diagnosis of human brucellosis is primarily based on serological tests and cultivation of the causative pathogen, without the knowledge of the underlying Brucella species or biovar. In addition, the scarcity of laboratories with adequate biosecurity measures to handle suspected specimens constitutes a significant challenge. Furthermore, the absence of full genome data limits our understanding of the genetic diversity of Brucella in Tunisia in comparison to the strains circulating in the North African region and the world. In the present study, a total of 36 bacterial isolates derived from human patients diagnosed with brucellosis in Tunisia were subjected to examination. Real-time PCR confirmed all isolates as B. melitensis . In the subsequent core genome-based MLST analysis (cgMLST) based on 2706 target genes, the isolates formed two separate but closely related clusters with a distance of 140 alleles. The intra-cluster diversity was one to six alleles. In the larger geographical context and in comparison to almost 1000 other Brucella genomes, the isolates showed the highest genetic relationship to B. melitensis isolates from Italy and Egypt with distances of 130 and 150 alleles, respectively. All the isolates were most similar to the biovar 3 genotype. Markedly, strains from a reported brucellosis outbreak in Austria were grouped closely (26 and 27 alleles, respectively) together with strains from Tunisia, suggesting that this country may represent their geographical origin. This research represents a significant advancement in our understanding of B. melitensis strains circulating in the Maghreb region, as it is the first study to elucidate the molecular characterization of strains isolated from humans in Tunisia. The cgMLST analysis of the strains provided information on the regional distribution of the strains and the association with neighboring countries and significant outbreaks in the region. The data will form the basis of a future reference framework for strains circulating in the Mediterranean region.

Unlabelled: The pathogenic capacity of streptococcus agalactiae or Group B Streptococcus (GBS) has been increasing in nonpregnant adults. We carried out a study about the pathogenic capacity and susceptibility to antibiotics of GBS strains isolated between January 2003 and June 2004 in Farhat Hached hospital of Sousse (Tunisian general hospital)., Methods: Identification of strains was carried out according to usual bacteriological characters. Susceptibility of GBS to antibiotics was carried out according to CA-SFM recommendations., Results: during the study period, sixty strains were isolated. They were essentially isolated from the urinary tract (52%) and the skin (36.2%). Women accounted for 68 percent of the cases. Among the 30 hospitalized patients, 20 (66%) had serious underlying disease. Diabetes mellitus was predominant (80%). All group B streptococci isolates were susceptible to amoxicillin, penicillin G, vancomycin and to pristinamycin. Sixty four percent of isolates were susceptible to erythromycin. Among the invasive infection, caused by GBS in nonpregnant adults, skin and urinary tract infections were the most common. All isolates were susceptible to amoxicillin, penicillin G. vancomycin and to pristinamycin.