Molecular diversity of Klebsiella pneumoniae clinical isolates: antimicrobial resistance, virulence, and biofilm formation

Abstract

One of the mechanisms responsible for antibiotic resistance in Klebsiella pneumoniae is the enzymes produced by the bacteria; another important mechanism is the ability to form biofilm. In this study, antibiotic resistance, genes associated with virulence, and biofilm-forming properties of K. pneumoniae strains were investigated. A total of 100  K. pneumoniae isolates were obtained from different clinical samples identified by Matrix-Assisted Laser Desorption/Ionization time-of-flight Mass Spectrometry. Antimicrobial susceptibility testing was performed with the Phoenix 100 apparatus. The biofilm forming properties of strains were determined by the microtiter plate method. For molecular analysis, genes encoding the carbapenemase enzyme (bla_OXA-48, bla_NDM-1, bla_IMP, and bla_VIM) and biofilm-related genes (treC, luxS, mrkA, and wza) were investigated by polymerase chain reaction (PCR). While 76% of clinical isolates were resistant to three or more antimicrobials, 24% were classified as non-multidrug resistant (non-MDR). When biofilm-forming capacities of clinical isolates were tested, it was determined that the resistant-isolates produced 59.2% strong biofilm, and susceptible-isolates produced 12.5% strong biofilm. According to PCR results, carbapenemase genes were determined as follows: bla_OXA−48-70%, bla_NDM-49%, and bla_KPC-19%, bla_OXA-48/bla_NDM/bla_KPC-12%, bla_OXA-48/bla_NDM-26%, and bla_OXA-48/bla_KPC-4%. The biofilm-associated genes in bacterial isolates were determined as follows: luxS-98%, treC-94%, mrkA-88%, and wza-15%. In addition, Hierarchical Clustering Tree and Heatmap analysis revealed an association between isolates that lacks resistance genes and isolates lacks biofilm-formation related genes that were included in MDR or non-MDR classes. As a result, biofilm should be considered in the treatment of MDR infections, and therapy should be planned accordingly. In addition, pursuing the data and genes of antibiotic resistance is significant for combating resistance.

Keywords:

• Klebsiella pneumoniae
• antibiotic resistance
• carbapenemase
• biofilm

Authors’ contribution

All key decisions were made by all authors. AHTK had full access to all the data in the study and takes responsibility for the integrity of the data and accuracy of the data analysis. AHTK, MH, RA, SDD, CÇ, and AE contributed substantially to the study design, interpretation, and manuscript writing. All authors have read and approved the final manuscript. All authors meet the ICMJE authorship criteria.

Disclosure statement

There is no conflict of interest among the authors.

Ethical approval

This study was conducted with the approval of the Sivas Cumhuriyet University Noninvasive Clinical Research Ethics Committee (Date: 23.03.2022 and Decision No: 2022-03/26).

Additional information

Funding

None.