Introduction and Objectives: Klebsiella pneumoniae is a major pathogen implicated in nosocomial infections that is known to spread easily, and it is frequently associated with resistance to the highest-priority critically important antimicrobials. The purpose of this work was to determine the genetic diversity (MLST) among selected carbapenem-and ESBL-producing K. pneumoniae isolates from human urinary infections.
Materials and Methods: Forty-nine cefotaxime/ceftazidime-resistant K. pneumoniae isolates were obtained aleatory from urocultures from patients of a Portuguese hospital during June 2017-July 2018. Identification was performed by MALDI-TOF MS. Antimicrobial susceptibility against 13 antibiotics was analyzed by disk diffusion test. Detection of ESBLs and other resistance and integron genes, and molecular typing (for selected isolates) was performed by PCR/sequencing.
Results: ESBL-production was detected in 26.5% of the isolates (13/49), most of them associated with CTX-M-15 enzyme (n=10). It is important to note that all ESBL-positive and negative isolates carried the KPC2/3 gene. Regarding the ESBL-producing Klebsiella pneumoniae isolates, different sequence types (ST) were identified (ST/phylogenetic-group/β-lactamase): ST15/CTX-M-15, SHV-28; ST15/CTX-M-15, SHV-12; ST280/CTX-M-15, SHV-27; ST280/SHV-27 and ST147/SHV-12. Additionally, the selected ESBL-negative isolates were typed as ST15/SHV-28, ST34/SHV-26 and ST348/SHV-11.
Conclusion: These findings indicate the genetic diversity among urinary infections isolates in our hospital. Furthermore, the KPC2/3 is the main mechanism of carbapenem resistance in K. pneumoniae isolates, frequently associated with CTX-M-15 enzyme.
