Antibiotic Susceptibility, Biofilm-Forming Ability, and Prevalence of Extended-Spectrum Beta-Lactamase (ESBL)- and Biofilm-Associated Genes Among Klebsiella pneumoniae Isolates from Hospitalized Patients in Northwest of Iran

Klebsiella pneumoniae is an opportunistic bacterium, which is globally recognized for its high prevalence and antimicrobial resistance (AMR). Biofilm-forming capability, susceptibility testing, and phenotypic confirmatory test for extended-spectrum beta-lactamase (ESBL)-producing isolate recognition of 104 K. pneumoniae isolates were performed according to the Clinical Laboratory Standard Institute (CLSI) guidelines. The prevalence of ESBL-associated genes bla-VIM, bla-NDM, and bla-OXA-48, as well as biofilm-associated genes luxS, fimH1, wza, and mrkD, was determined by multiplex PCR. The highest resistance rate was against ampicillin (100.0%). Among the 104 K. pneumoniae isolates, 52 (50.0%) and 31 (29.8%) isolates were determined as multi- and extensively drug resistant (MDR, XDR), respectively. Moreover, 21 (40.4%) isolates were determined as ESBL producing. Among 50 biofilm-producing K. pneumoniae isolates, 7 (14.0%), 15 (30.0%), and 28 (56.0%) isolates exhibited high, moderate, and weak levels of biofilm formation, respectively. A number of 41 (78.8%) isolates were susceptible to colistin, and 10 (19.2%) were resistant. AMR was significantly higher (P < 0.05) in the biofilm-forming isolates compared with non-biofilm formers.

Automated summary

Klebsiella pneumoniae is a global opportunistic bacterium with high prevalence and antimicrobial resistance. A study was conducted on 104 K. pneumoniae isolates to determine their biofilm-forming capability, susceptibility to antibiotics, and presence of extended-spectrum beta-lactamase (ESBL) genes. The highest resistance rate was observed against ampicillin (100.0%). Among the isolates, 50.0% were multi-drug resistant (MDR), 29.8% were extensively drug resistant (XDR), and 40.4% were ESBL producers. Biofilm-forming isolates showed significantly higher antimicrobial resistance compared to non-biofilm formers (P < 0.05).