Background: Urinary tract infections (UTIs) are major healthcare problems that are usually treated empirically. However, antimicrobial resistance has been increasing across many settings. This study aims to elucidate the antibiotic resistance profiles of three common uropathogens, Escherichia coli (E. coli), Klebsiella pneumoniae (K. pneumoniae), and Proteus mirabilis (P. mirabilis) and compare between extended spectrum beta-lactamase (ESBL) and non-ESBL strains among Lebanese patients. Methods: This retrospective study was conducted at multiple tertiary healthcare centers in South Lebanon, between January and September 2017, including 551 patients of all age groups. Demographic, clinical, and laboratory data of patients were collected and analyzed statistically. Results: The prevalence of UTI in Lebanon was highest in adults between 19 and 64 years (44%). E. coli was the predominant uropathogenic organism (67.1%) followed by K. pneumoniae (10%) and P. mirabilis (3.7%). ESBL represented 32.9% of the UTI agents. The three common uropathogens studied were found to be most susceptible to imipenem (100%) and meropenem (100%). Interestingly, 115 (25.1%) out of the 458 E. coli isolates were resistant to more than eight antibiotics while 107 (23.4%) were susceptible to all antibiotics studied. Conclusions: Our study underlined the importance of adequate antimicrobial prescription for UTIs in Lebanon to avoid multidrug resistance.

Introduction: Extended-spectrum – beta lactamases (ESBLs) are increasingly detected globally among Escherichia coli and Klebsiella pneumoniae. The correlation between antibiotics use and resistance, though not fully described, has been addressed and shown in several studies. In this study, the profiles of ESBLs in E. coli and K. pneumoniae isolated from two Lebanese hospitals and their relationship to antibiotic consumption were determined. Methodology: A total of 205 E. coli and 67 K. pneumoniae isolates resistant to third- or fourth-generation cephalosporins were collected between January 2011 and January 2012. Antibiotic susceptibility and consumption data were also collected from 2010–2012. Double-disk synergy and Etest ESBL assays were performed, followed by PCR for ESBL genes. Pulsed-field gel electrophoresis (PFGE) was performed for representative isolates. Statistical analysis for consumption and susceptibility data over 3 years was performed. Results: As expected, CTX-M-15 was predominant. In both hospitals, strains of E. coli and K. pneumoniae harbored at least one ESBL, and in some cases (23%) harboured four different ESBLs. A significant correlation was detected between total use of antimicrobial agents and resistance to various antibiotics. This was obvious for the use of penicillins and resistance to aztreonam, ceftazidime and ciprofloxacin, and use of third- and fourth-generation cephalosporins and resistance to ceftazidime, cefuroxime, cefoxitin and ciprofloxacin in both bacteria. Conclusions: This study shows the predominance of CTX-M-15 among cephalosporin-resistant E. coli and K. pneumoniae in Lebanese hospitals and highlights the direct relationship between the use of antibiotics and the emergence of resistance in bacteria.

Introduction: Increasing carbapenem resistance in Acinetobacter spp calls for the appraisal of alternative strategies in Acinetobacter spp infection therapy. This study aims at evaluating colistin-carbapenem combination against Acinetobacter spp using the checkerboard, Etest, and time-kill methods. Methodology: One hundred nonrepetitive Acinetobacter spp isolates were collected from patients admitted at the Saint-George-Hospital-University-Medical-Center over a one year period. The identification was performed using the API20NE and confirmed by the amplification of the blaOXA-51-like. Susceptibility to colistin, and carbapenems were determined using the Etest, microdilution methods and interpreted according to the CLSI, 2015. Detection of the carbapenemases was performed by PCR amplification method. Clonality was determined by the 3-Locus PCR-typing and ERIC-PCR methods. The synergistic potential of the combination was determined by calculating the Fractional-Inhibitory-Concentration-Index, which determines a synergistic, additive, indifferent or antagonistic effect. Results: In our study (84%) of the isolates were carbapenem resistant. Only one strain showed resistance to colistin. (99%) and (77%) of the Acinetobacter spp isolates harbored blaOXA-51-like and blaOXA-23-like respectively. (86.2%) of the A.baumannii isolates pertained to the International Clone II. An additive effect of the colistin-carbapenem combination was determined using the 3 methods. A decrease of 2.6 and 2.8 folds in the MIC of colistin was showed in colistin-meropenem and colistin-imipenem, respectively (p < 0.001). The Colistin-meropenem showed better effects when compared to colistin-imipenem (p < 0.05). Only a few isolates showed a synergistic effect in the time-kill assay. Conclusion: Our study showed that the decrease in the MIC of colistin following colistin-carbapenem combination might be a promising antimicrobial approach for treating carbapenem-resistant Acinetobacter spp.

Introduction: The worldwide emergence of antimicrobial resistance in Acinetobacter spp and their clonal dissemination call for the investigation into Acinetobacter spp epidemiology. Methodology: 100 nonrepetitive Acinetobacter spp isolates were recovered from patients admitted at Saint- George-Hospital-University-Medical-Center-Beirut, in a one-year period. Identification of the isolates was determined by the API20NE and confirmed by PCR amplification of blaOXA-51-like. Susceptibility to carbapenems and colistin were determined by the microdilution method and interpreted according to the CLSI, 2015.The β lactamase inhibitors: PBA, EDTA, and Cloxacillin were used for the detection of KPC, MBL and AmpC, respectively. ESBL producers were detected whenever a keyhole effect was observed between 3rd generation cephalosporin and Augmentin®. Simplex PCR was conducted for the genotypic detection of β lactamases. ERIC and 3LST-PCR were performed to determine the clonality of the isolates. Results: Our findings showed that 84% were carbapenem resistant. Only one isolate was resistant to colistin. Phenotypically, 23 were ESBL, 15 KPC, 5 AmpC, and 4 MBL producers. PCR analysis showed that 99%, 93%, 77% and 3 % of the isolates harbored blaOXA-51-like, blaADC, blaOXA-23-like, and blaOXA-40-like, respectively. ERIC-PCR analysis showed that A.baumannii isolates were clustered in 19 possibly related and 30 closely related subtypes. The 3-LST-PCR showed that 86.2% of the A.baumannii isolates pertained to the ICII (international clone II). Conclusion: Our study showed a predominance of OXA-23-like producers and dissemination of ICII. Inhibitor based method was shown not to be accurate for the prediction of carbapenemases in Acinetobacter spp. Infection control measures are needed for management of Acinetobacter spp infections.