Abstract Introduction: Extended-spectrum β-lactamases (ESBLs), AmpC type, carbapenem resistant Enterobacteriaceae (CRE), are important mechanisms of resistance among Enterobacteriaceae. The aim of this study was to investigate the prevalence of ESBL, AmpC and CRE among Enterobacteriaceae isolates recovered from pediatric patients in Tripoli, Libya. Methods: This cross-sectional study was carried out in Tripoli Children Hospital (TCH), a total of 915 Gram negative bacteria isolates were evaluated for susceptibility to a panel of antimicrobials and were analyzed phenotypically for the ESBL, AmpC type and CRE using chromagen media, E-test and combination disc test. Results: The predominant organisms were Escherichia coli (56.8%) and Klebsiella spp. (21.4%). The overall prevalence of ESBL producing Enterobacteriaceae was 24.5% (224/915). Out of 224, Enterobacteriaceae proved ESBL producer, Klebsiella spp. (54%) and E. coli (34.4%) were the leading ESBL producers. ESBL-producers were more often resistant to major classes of antibiotics compared with non-ESBL producers, significantly high resistance rates (P < 0.001) were observed for ceftriaxone, cefepime, and ceftazidime (87.5 - 95.9%) among ESBL producers compared to non-ESBL producers (7.2 - 13.5%). MDR was documented for 50/224 (22.3%) of ESBL producers and was significantly higher (P < 0.0001) among ESBLs compared with non-ESBL producer isolates. Phenotypic detection of AmpC revealed 60/915 (6.6%) isolates as potential AmpC β-lactamase producers, E. coli exhibited a lower level of AmpC (8.3%) compared with Klebsiella spp. (56.6%). The overall prevalence of CRE was 9% (83/915). Carbapenemase-producing organisms in this study were as follows: Klebsiella spp. (44.6%); Acinetobacter spp. (24%); Pseudomonas spp. (9.6%). Conclusion: This study revealed that the prevalence of ESBL, AmpC, CRE and MDR Enterobacteriaceae isolates in Children hospital was within acceptable frequency. arabic 11 English 91
Abdulaziz Zorgani, Abdulla Bashein, (1-2017)

Introduction: Extended-spectrum β-lactamases (ESBLs), including the AmpC type, are important mechanisms of resistance among Klebsiella pneumoniae and Escherichia coli isolates. Objective: The aim of the study was to investigate the occurrence of AmpC-type β-lactamase producers isolated from two hospitals in Tripoli, Libya. Methods: All clinical isolates (76 K. pneumoniae and 75 E. coli) collected over two years (2013-2014) were evaluated for susceptibility to a panel of antimicrobials and were analyzed phenotypically for the ESBL and AmpC phenotype using E-test and ESBL and AmpC screen disc test. Both ESBL and AmpC-positive isolates were then screened for the presence of genes encoding plasmid-mediated AmpC β-lactamases by polymerase chain reaction (PCR). Results: Of the K. pneumoniae and E. coli tested, 75% and 16% were resistant to gentamicin, 74% and 1.3% to imipenem, 71% and 12% to cefoxitin, 80% and 12% to cefepime, 69% and 22.6% to ciprofloxacin, respectively. None of the E. coli isolates were multidrug resistant compared with K. pneumoniae (65.8%). K. pneumoniae ESBL producers were significantly higher (85.5%) compared with (17.3%) E. coli isolates (P
Abdulaziz Zorgani, Abdulla Bashein(1-2017)

Acinetobacter baumannii is an opportunistic pathogen causing various nosocomial infections. The aim of this study was to characterize the molecular support of carbapenem-resistant A. baumannii clinical isolates recovered from four hospitals in Tripoli, Libya. Bacterial isolates were identified and antibiotic susceptibility testing was per-formed using automated system. Carbapenem resistance determinants were studied phenotypically using two dif-ferent techniques: E-test; chromogenic culture media. Polymerase chain reaction (PCR) amplification was used to determine the presence of bla OXA23 and blaOXA51 genes among isolates. A total of 119 isolates were characterized, overall the resistance prevalence was extremely high for aminoglycosides (79-96.6%), fluoroquinolones (94-96%), cephalosporins (96.6-100%) and carbapenemes (93.2-100%), all isolates were susceptible to colistin. In addition, 97.5% of isolates were identified as multidrug resistance (MDR). Varying degree of phenotypic detection of car-bapenemes was determined; highest levels of carbapenemes were detected using chromogenic media (76.5%) com-pared with E-test (45.4 %). The carbapenem resistance-encoding genes detected were blaOXA23 (84%) and blaOXA51 (73.1%); the highest occurrence of blaOXA23 was demonstrated in Tripoli’s Central Hospital (5/5; 100%) then in Tripoli Medical Center (44/51; 86.27%). The co-occurrence of these genes was demonstrated in (75/119; 63%) showing dissemination of carbapenemes resistance MDR A. baumannii in hospitals. This study shows that the high prevalence of OXA-23 contribute to antibiotic resistance in … arabic 14 English 113
Nada Elgrew, Abdulla Bashein(1-2016)