Relationship between antibiotic resistance, efflux pumps, and biofilm formation in extended-spectrum β-lactamase producing Klebsiella pneumoniae

Abstract

Klebsiella pneumoniae is an important pathogen both in community and hospital environment. In this study, we aimed to determine the antibiotic susceptibilities, expression levels of AcrA, ketM, kdeA, kpnEF, and kexD genes related to efflux pump and biofilm formation in 100 extended-spectrum β-lactamase producing Klebsiella pneumoniae. The relative expression levels of AcrA, ketM, kdeA, kpnEF, and kexD were determined by quantitative real-time PCR and biofilm formation was screened by microtiter plate assay. Based on CLSI breakpoints, zone diameters showed that 72% of isolates were resistant to ceftazidime, 79% to aztreonam, 54% to ciprofloxacin, 32% to ertapenem, 74% to tobramycin, 65% to tetracycline and all isolates were resistant to ampicillin, ceftriaxone, and cefotaxime. The relative expression of AcrA was upregulated in ciprofloxacin susceptible isolates and also upregulation of newly described efflux pump, kexD, was correlated with tobramycin and aztreonam resistance. A significant correlation was observed between resistance-nodulation-division and single-type efflux pumps. On the other hand, ciprofloxacin susceptible isolates formed stronger biofilms than resistant isolates. The up or down regulation of efflux pumps didn’t enhance biofilm formation capacity.

Keywords:

• Klebsiella pneumoniae
• ESBL
• Antibiotic resistance
• Biofilm formation
• Efflux pump

Acknowledgments

We would like the thank specialists at Central Research Laboratory for helpful approach and technical assistance.

Author contributions

İbrahim Türkel: performed the experiments, data analysis and interpretation, Tuba Yıldırım: designed the experiments, data analysis and interpretation, drafting of manuscript, revising of manuscript; Burak Yazgan: designed the experiments, performed the experiments, data analysis and interpretation; Melek Bilgin: collected the isolates, data analysis, and interpretation; Eşe Başbulut: collected the isolates.

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes on contributors

İbrahim Türkel is a MSc. student at Amasya University. Main research areas are antimicrobial resistance, virulence factors and efflux mediated antibiotic resistance. He has presented papers at conferences about efflux pump expression and biofilm forming capacities of Klebsiella pneumoniae.

Tuba Yıldırım (corresponding author) carried out a PhD at Gebze Technical Universit. Her research focuses on molecular microbiology, molecular characterisation of pathogen bacteria, and antibiotic resistance mechanisms. Now she is working as an associate professor in Department of Biology of Amasya University and supervisor of Central Research Laboratory.

Burak Yazgan carried out a PhD at Marmara University and has been working in Central Research Laboratory and also department of medical services and techniques, Amasya University, Sabuncuoğlu Serefeddin, Vocational Higher School of Health Services.

Melek Bilgin graduated from Medical School of Ondokuz Mayıs University and carried out her expertise as a microbiology specialist. Now she is the supervisor of Microbiology Laboratory of Samsun Education and Research Hospital.

Eşe Başbulut gratuated from Medical School of Ankara University in 1997 and also carried out her expertise as a microbiology specialist in 2008. Now she is working in Samsun Education and Research Hospital as a microbiology specialist.

Supplemental data

Supplemental data for this article can be accessed here.

Additional information

Funding

This work was supported by the Scientific Research Program of Amasya University [Project number: FMB-BAP-14-079].