Characterization of β-Lactamase Genes among Multidrug- and Extensively Drug-Resistant Acinetobacter and Enterobacteriaceae Species Causing Infections in Critically Ill Patient

Abstract

Background: Multidrug resistant infection is the leading cause of ICU morbidity and mortality. Gram-negative bacilli are the most prevalent pathogens with Acinetobacter being the most resistant. Objectives: Phenotypic and genotypic characterization of multidrug-and extensively drug-resistant Acinetobacter and Enterobacteriaceae species causing infections in critically ill patients with detection of targeted β-lactamase genes and its impact on patients' morbidity and mortality. Methodology: Antibiotic susceptibility testing was done. Genes for class A and class B β-lactamases were detected by multiplex polymerase chain reaction (PCR) and 5 carbapenemases genes were detected by real time PCR using GeneXpert Carba-R system. Results: 16.6 % of A. baumannii were MDR, 50% were XDR, 50% of K. pneumoniae were XDR and 100% of P. stuartii were XDR. Detected genes included bla SHV , bla CTX-M , bla GIM-1 , bla SIM-1 , bla OXA-48 and bla NDM-1 . Conclusion: MDR/XDR infections had a significant impact on patients' mortality. Molecular epidemiology is crucial to guide infection control committees about preventive measures that can contain MDR/XDR infections and prevent their detrimental effect on patients' outcome.

Biofilm Formation by Acinetobacter Species Isolated from Intensive Care Units: Unveiling the Impact on Antibiotic Resistance

“…A similar rate was reported by a previous study that used colistin for susceptibility testing 28 . Lower rates were reported in Italy (69%) 29 , Greece (29%) 30 , Saudi Arabia (5.5%) 27 , and Egypt (5%) 31 , whereas other studies demonstrated 100% susceptibility to polymyxins 20, 21 . The high rate of resistance to polymyxin B in our study may be attributed to the increased use of polymyxin B in the treatment of carbapenem-resistant Acinetobacter infections, particularly in ICUs where bacterial selective pressure is frequently high.…”

“…Similarly, a study from Egypt noticed that 91.7% of isolates were XDR and 8.3% of them were MDR 20 . Another study conducted by Khalifa et al 27 revealed that 50% of Acinetobacter isolates were XDR and 16.6% were MDR. It seems that the emergence of XDR and MDR Acinetobacter strains in our hospital is strongly linked to the selective pressure caused by the prolonged use of broad-spectrum antimicrobials, thus limiting the therapeutic strategies available to control infections.…”