Molecular detection of Extended-Spectrum β-lactamases (ESBLs) and biofilm formation in uropathogen Klebsiella pneumoniae in Iran

Uropathogenic Klebsiella pneumoniae is one of the well-kown uropathogens that have the main rule in biofilm formation. Increased prevalence of ESBL enzyme is one of the therapeutic problems. However, the aims of this study were to characterize  the ability of biofilm formation and ESBL-producing isolates produced by urinary tract infection’s K. pneumoniae to identify the prevalence of this type of infection in the studied area.

Between the 500 nonrepetitive clinical isolates, 128 isolates were detected as K. pneumoniae. Biofilm production of these isolates was showed by Merrit and Christensen method. The standard Kirby-Bauer disk diffusion method was used for antimicrobial susceptibility testing.  The phenotype ESBL was confirmed by double disc synergy test (DDST). Genotypic identification of ESBLs did by molecular detection. The statistical analysis was done  using software IBM SPSS Statistics (SPSS Inc) and chi-square and Fisher exact tests.

The result of microtiter plate was observed and it was found that 86 (67.2%) isolates had weak biofilm, 24 (18.8%)  moderate biofilm, and 18 (14.1%) strong biofilm. Also, 57 (44.5%) out of 128 isolates were diagnosed as MDR. The highest frequency of resistance was identified for cefotaxime 60 (46.9%) and tetracycline 60 (46.9%), and the lowest rate was for amikacin 16 (12.5%). The results of DDST showed 55 of 128 (43%) produced ESBL enzymes. PCR detection in ESBL-producing isolates showed contained blaTEM  33 of 55(63.1%), and blaVEB  13 of 55 (23% ). Also, 1 of 55 (2%) had both blaTEM and blaVEB. Also, 5 of 13 (38.4%) isolates that had the blaVEB gene were also MDR and had weak biofilm (8/13; 61.5%),  intermediate biofilm (3/13; 23%),  and strong biofilm (2/13; 15.4%).

To decrease treatment complications and mortality rate of drug-resistant bacterial infections, rapid detection of β-lactamases genes and evaluation of these properties and infection management programs can help to prevent the transmission of drug resistant-strains.