Studies on molecular epidemiology of ES beta L-producing Klebsiella pneumoniae isolated from patients hospitalized in a specialist hospital in southern Poland

Introduction. Extended-spectrum beta-lactamase (ES beta L)-producing Klebsiella pneumoniae is currently one of the most common causes of nosocomial infections worldwide. The study aimed to characterize antibiotic resistance profile, the prevalence of selected genes encoding ES beta Ls, virulence, and the genetic relationship in 139 K. pneumoniae isolates identified in John Paul II Specialist Hospital in Southern Poland, collected in 2016. Materials/Methods. Bacterial identification and the preliminary antibiotic susceptibilities was performed using the VI-TEK(R) 2 Compact automated system. Genes encoding ES beta Ls were amplified by CTX-Mplex PCR and PCR reactions. The presence of nine genes encoding virulence factors was studied by multiplex PCR. Clonality was investigated by PFGE after digestion with SpeI endonuclease. Results. K. pneumoniae were mostly recovered from the respiratory tract (40.3%), urine (32.4%), wound swabs (19.4%) and blood (5%). In summary, 82.7% of strains were classified as multidrug resistant (MDR). All isolates were confirmed as ES beta L producers and carried bla(CTX-M-type) (85.6%), bla(SHV) (82%), bla(TEM) (77.7%), bla(CTX-M-9) (75.6%) and bla(CTX-M-1) (1.4%) in various combinations. Moreover, triple bla genes were observed in 72% of isolates. The most common virulence-as-sociated genes found among the isolates were entB (91.4%), ybtS (55.4%), iutA (55.4%), magA (53.2%), kfu (14.4%), K2 (11.5%), mrkD (10.1%), rmpA (7.9%) and allS (5%). The PFGE analysis identified 4 major clusters (A-D) comprising 61% of the entire collection. Conclusions. Our results indicate that the presence of a wide variety of MDR K. pneumoniae harbor ES beta Ls and virulence genes. Studies on molecular epidemiology of ES beta L-producing K. pneumoniae isolates are needed, particularly for epidemiological surveillance in the hospital environment.