Susceptibility, phenotypes of resistance, and extended-spectrum β-lactamases in Acinetobacter baumannii strains

Abstract

Abstract:Acinetobacter baumannii plays an increasing role in the pathogenesis of infections in humans. The bacilli are frequently isolated from patients treated in intensive care units. A growing resistance to antibiotics is leading to the emergence of strains that are multidrug-resistant and resistant to all available agents. The objective of this study was to assess susceptibility to antibiotics and to determine the presence and current level of the extended-spectrum b-lactamases (ESBLs) and attempt to isolate the Acinetobacter baumannii strain carrying the bla PER gene. A total of 51 strains of A. baumannii identified by phenotypic features were examined. That the strains belonged to the species was confirmed by the presence of the bla OXA-51-like gene. A broth microdilution method was used for antibacterial susceptibility testing. The occurrence of ESBLs was determined using phenotypic double-disk synergy tests. The PCR technique was used to confirm the presence of the bla PER-1 gene encoding ESBL. The most active antibiotics were meropenem, cefepime and ampicillin/sulbactam, with susceptibility shown by 76.5%, 60.8% and 56.9% of the strains, respectively. The strains exhibited the highest resistance (> 75%) to piperacillin, tetracycline, ciprofloxacin and cefotaxime. Phenotypic tests revealed ESBL mechanism of resistance in approximately 20% of Acinetobacter baumannii isolates. However, the PCR technique did not confirm the presence of the bla PER-1 gene in any of the Acinetobacter baumannii strains examined in our hospital. Acinetobacter baumannii strains demonstrate considerable resistance to many groups of antibiotics. Our findings indicate the involvement of enzymes belonging to families other than PER b-lactamase in resistance to b-lactams in

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

“…On the contrary, higher results were reported in previous studies for ESBL producers bacteria with range from 20% up to 85% [29–31]. …”

Investigation of Class 1 Integrons With Antibiotic Resistance Genes in Multidrug-Resistant Acinetobacter Baumannii Strains and Determination of Plant Extract Effects on Multidrug-Resistant Isolates

“…A. baumannii, a Gram-negative, nosocomial pathogen resistant to most current antibiotics, has become a major challenge for modern healthcare systems [1,2]. A. baumannii, as free-living planktonic cells or biofilms, can live at a wide range of temperature, pH and humidity levels.…”

Molecular Identification and Antimicrobial Resistance Profile of Acinetobacter baumannii Isolated From Nosocomial Infections of a Teaching Hospital in Isfahan, Iran

“…Resistance to broad spectrum β-lactams, aminoglycosides, fluoroquinolones, and carbapenems are observed in this bacteria , which complicate the treatment of this pathogen (2). In the last decade, Acinetobacter baumannii became more prevalent as an opportunistic pathogen, specifically as a multidrug-resistant agent (MDR) using different mechanisms of drug resistance (3,4). The emergence of extensively drug-resistant A. baumannii (XDRAB) limits the treatment options and causes a serious threat to hospital acquired infections (HAI) control.…”