Molecular Study of Acinetobacter baumannii Isolates for Metallo-β-Lactamases and Extended-Spectrum-β-Lactamases Genes in Intensive Care Unit, Mansoura University Hospital, Egypt

Abstract

Acinetobacter baumannii (A. baumannii) has been known as a causative pathogen of hospital acquired infections. The aim of this study is to examine the presence of A. baumannii among clinical isolates from intensive care unit (ICU) in Mansoura University Hospital (MUH), its antibiotic resistance pattern, and prevalence of antibiotic resistance genes metallo-β-lactamases (MBLs) and extended-spectrum-β-lactamases (ESBLs) among A. baumannii isolates. A. baumannii was identified by colony morphology, API 20E, and confirmed by detecting the bla OXA-51-like carbapenemase gene by PCR. Phenotypic expression of MBLs resistance was demonstrated by Combined Disk Test (CDT) in 273 isolates (97.5%) and of ESBLs was demonstrated by double disc synergy method (DDST) in 6 isolates (2.1%). MBLs genes were positive in 266 isolates (95%) and ESBLs genes were positive in 8 isolates (2.9%). The most frequent genes of MBLs studied genes were IMP (95.7%) followed by SIM and GIM (47.1% and 42.9%; resp.). For ESBL genes, the most frequent gene was TEM (2.9%). From this study, we conclude that multidrug resistant (MDR) A. baumannii with MBLs activity was the most common isolate. Careful monitoring for the presence of MDR A. baumannii among hospitalized patients is recommended to avoid wide dissemination of antibiotic resistance.

Co-Existence of Carbapenemase-Encoding Genes in Acinetobacter baumannii from Cancer Patients

“…Carbapenem insensitivity was detected in 70.8% (34/48) of collected isolates, which is similar to other studies carried in Egypt by Sultan and Seliem [24]. Others have shown a higher prevalence for CRAB reaching 90% [10,25,26], which suggests that Egypt is the topmost country in the region in CRAB prevalence [27]. CRAB treatment typically relies on other last-resort antibiotics such as colistin and tigecycline and sometimes antibiotic combinations [28].…”

“…High prevalence of bla NDM gene (67.7% of CRAB isolates) was observed in our study compared to previous studies carried out in Egyptian hospitals which showed bla NDM prevalence of 8% [40] and 39.3% [25] among CRAB isolates. The bla NDM-1 and bla NDM-2 -encoding genes were first described in A. baumannii isolated from Egyptian patients [41] and then a noteworthy spread of bla NDM -positive A. baumannii was detected in the Middle East [42].…”

Insights into Acinetobacter baumannii: A Review of Microbiological, Virulence, and Resistance Traits in a Threatening Nosocomial Pathogen

“…They hydrolyze all penicillins and cephalosporins with the exception of cephamycins [128]. CTX-M, GES, PER, SCO, SHV, TEM, and VEB are among identified class A β-lactamases in A. baumannii [129][130][131][132]. While some of these, like SCO-1 and TEM-1, are narrow-spectrum, others like CARB-10, CTX-M-2, CTX-M-15, GES-14, PER-1, PER-7, and SHV-5 are extended spectrum β-lactamases (ESBLs) [133,134].…”

Molecular Characterization of Carbapenem-Resistant Acinetobacter baumannii Clinical Isolates from Egyptian Patients

“…accounted for 95.7%. However, the authors didn't investigate blaNDM among the studied isolates (21). Another Egyptian study has detected blaNDM among 66.7% of 50 A.baumannii isolates.…”