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Background Extended-spectrum β-lactamase-producing organisms causing urinary tract infections are increasing in incidence and pose a major impendence to health-care facility, having limited therapeutic options. This study aimed to assess the prevalence of ESBLs in Enterobacteriaceae isolates causing urinary tract infections in Gaza strip, Palestine, and to characterize β-lactamase types and associated resistance genes. Methods Eighty-five Enterobacteriaceae isolates were recovered from urinary tract infections within three months in Gaza Strip hospitals. The characterization of β-lactamase genes and the genetic environments of CTX-M, the identification of associated resistance genes, and the presence and characterization of integrons were tested by PCR and sequencing. Results The occurrence rate of ESBL among tested isolates was 30 (35.3%), and among ESBL-positive isolates, blaCTX-M was the highest followed by blaTEM. ESBL-CTX-M-1 group was confirmed in 93.3%, and the remaining carried CTX-M-9 group. CTX-M-15, CTX-M-3, CTX-M-1, CTX-M-14, CTX-M-27, and CTX-M-37 enzymes were demonstrated among the isolates with the majority (73%) being CTX-M-15. ISEcp-1 was demonstrated in 27 (90%, high incidence) of ESBL isolates. Class 1 integrons have been detected in higher rates (53.3%) in ESBL-positive isolates in comparison with non-ESBL isolates (6, 33.3%). Cassettes of integron-1 contain (aadA1, aadA2, aadA5, dfrA5, dfrA7, dfrA12, and dfrA17) genes. The aac(6′)-Ib-cr gene was demonstrated in 36.7% of ESBL-positive isolates. Conclusions This study indicates that blaCTX-M-15 was the most prevalent β-lactamase in this region. Our study demonstrates for the first time in Palestine the identification of blaCTX-M-15 in P. rettgeri and S. liquefaciens, also blaCTX-M-37 in E. cloacae. The coexpression of multiple β-lactamase genes with aac(6′)-Ib-cr and qnr in the presence of ISEcp-1 and integrons in individual strains will increase the dissemination of highly resistant strains. ESBL producers were more resistant than non-ESBLs producers for almost all tested antibiotics.

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BackgroundThe spreading of antibiotic resistant bacteria is becoming nowadays an alarming threat to human and animal health. There is increasing evidence showing that wild birds could significantly contribute to the transmission and spreading of drug-resistant bacteria. However, data for antimicrobial resistance in wild birds remain scarce, especially throughout Africa. The aims of this investigation were to analyze the prevalence of ESBL-producing E. coli in faecal samples of wild birds in Tunisia and to characterize the recovered isolates.ResultsOne hundred and eleven samples were inoculated on MacConkey agar plates supplemented with cefotaxime (2 μg/ml). ESBL-producing E. coli isolates were detected in 12 of 111 faecal samples (10.81%) and one isolate per sample was further characterized. β-lactamase detected genes were as follows: blaCTX-M-15 (8 isolates), blaCTX-M-15 + blaTEM-1b (4 isolates). The ISEcp1 and orf477 sequences were found respectively in the regions upstream and downstream of all blaCTX-M-15 genes. Seven different plasmid profiles were observed among the isolates. IncF (FII, FIA, FIB) and IncW replicons were identified in 11 CTX-M-15 producing isolates, and mostly, other replicons were also identified: IncHI2, IncA/C, IncP, IncI1 and IncX. All ESBL-producing E. coli isolates were integron positive and possessed “empty” integron structures with no inserted region of DNA. The following detected virulence genes were: (number of isolates in parentheses): fimA (ten); papC (seven); aer (five); eae (one); and papGIII, hly, cnf, and bfp (none). Molecular typing using pulsed-field gel electrophoresis and multilocus sequence typing showed a low genetic heterogeneity among the 12 ESBL-producing strains with five unrelated PFGE types and five different sequence types (STs) respectively. CTX-M-15-producing isolates were ascribed to phylogroup A (eleven isolates) and B2 (one isolate).ConclusionTo our knowledge, this study provides the first insight into the contribution of wild birds to the dynamics of ESBL-producing E. coli in Tunisia.

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Necrotic enteritis (NE), caused by Clostridium perfringens, is an emerging issue in poultry farming. New approaches, other than antibiotics, are necessary to prevent NE development and the emergence of multidrug-resistant bacteria. Enterococci are commensal microorganisms that can produce enterocins, antimicrobial peptides with activities against pathogens, and could be excellent candidates for protective cultures. This study aimed to screen and characterize Enterococcus strains of poultry origin for their inhibitory activity against C. perfringens. In total, 251 Enterococcus strains of poultry origin plus five bacteriocin-producing (BP+) E. durans strains of other origins were screened for antimicrobial activity against the indicator C. perfringens X2967 strain using the “spot on the lawn” method. We detected thirty-two BP+ strains (eleven Enterococcus faecium, nine E. gallinarum, eight E. faecalis, three E. durans, and one E. casseliflavus). We further studied the antimicrobial activity of the supernatants of these 32 BP+ strains using agar well diffusion and microtitration against a collection of 20 C. perfringens strains. Twelve BP+ enterococci that were found to exhibit antimicrobial activity against C. perfringens were characterized using whole genome sequencing. Among these, E. faecium X2893 and X2906 were the most promising candidates for further studies as protective cultures for poultry farming. Both strains belong to the sequence type ST722, harbor the genes encoding for enterocin A and enterocin B, do not possess acquired resistance genes, do not carry plasmids, and present the acm gene, which is implicated in host colonization. Further research is needed to determine the utility of these strains as protective cultures.