Article Type

Original Study


Objectives The aims of this study were to investigate the prevalence of Acinetobacter spp. in Menoufia University Hospitals, to investigate their antimicrobial susceptibility patterns, and to assess carbapenemases production in these isolates. Background Acinetobacter spp. are important opportunistic pathogens responsible for nosocomial infections. Materials and methods This study was conducted on 603 clinical samples from patients admitted to Menoufia University Hospitals. Acinetobacter spp. were identified by standard microbiological methods and API20NE test kits. Antimicrobial susceptibility was tested using disk diffusion and agar dilution methods. Imipenem-resistant Acinetobacter isolates were further tested for metallo-β-lactamase (MβL) production. Results This study was conducted at Medical Microbiology and Immunology Laboratory, Faculty of Medicine, Menoufia University. Acinetobacter spp. represented 10.6% of all collected nosocomial isolates. With regards to API20NE results, A. baumanii was the predominant Acinetobacter spp. (80.8%) followed by A. baumanniiA. calcoaceticus complex (7.7%), A. lwoffii (5.8%), A. haemolyticus (3.8%), and A. pitti (2.6%). Acinetobacter isolates were highly resistant to cefepime (92.3%), ampicillin–sulbactam, piperacillin, piperacillin–tazobactam, ceftazidime, tobramycin (91% for each), amikacin (84.6%), and imipenem (67.9%). Overall, 56.4% of Acinetobacter isolates were susceptible to tigecycline. On agar dilution method, 96.2% of Acinetobacter isolates were found to be susceptible to colistin and 66.7% were imipenem resistant. Imipenem/ethylenediaminetetraacetic acid combined disk test showed that 81.1% of imipenem-resistant Acinetobacter were MβL producers, and multiplex PCR showed that 15.1% of imipenem-resistant Acinetobacter were positive for blaVIM2, but none of them were positive for blaIMP1 gene. Conclusion Acinetobacter spp. are serious nosocomial pathogens with high prevalence of carbapenems resistance. Production of carbapenemases, especially MβLs, is considered the main carbapenem-resistance mechanism. Tigecycline and colistin can be valuable therapeutic options for the treatment of Acinetobacter infections.