Occurrence of K1 and K2 serotypes and genotypic characteristics of extended spectrum β-lactamases-producing Klebsiella pneumoniae isolated from selected hospitals in Malaysia

• Published in: Asian Pacific Journal of Tropical Medicine
• Main Authors: Nurul Syazrah Anuar, Hazmin Hazman, Sharven Raj Jeyakumar, Mohd Nasir Mohd Desa, Hasni Idayu Saidi, Siti Norbaya Masri, Nur Afiza Aziz, Nurshahira Sulaiman
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wolters Kluwer Medknow Publications 2024
• Subjects: extended spectrum β-lactamases; klebsiella pneumoniae; capsular serotypes; genotypic; Arctic medicine. Tropical medicine; RC955-962; Arctic
• Online Access: https://doi.org/10.4103/apjtm.apjtm_303_23; https://doaj.org/article/b3ad2284eccf45028a57c9b35685e86f

Objective: To determine the distribution, phenotypic and genetic background of extended spectrum β-lactamases (ESBL)-producing Klebsiella (K.) pneumoniae clinical isolates associated with K1 and K2 serotypes in two selected hospitals in Malaysia. Methods: A total of 192 K. pneumoniae isolates were collected and subjected to antibiotic susceptibility, hypermucoviscosity test and multiplex PCR to detect the presence of K1- and K2- serotype associated genes. Multilocus sequence typing (MLST) was performed on ESBL-producing K. pneumoniae isolates presented with K1 and K2 serotypes, followed by phylogenetic analysis. Results: A total of 87 out of 192 (45.3%) of the K. pneumoniae isolates collected were ESBL producers. However, only 8.3% (16/192) and 10.9% (21/192) of the total isolates were detected to carry K1- and K2-serotype associated genes, respectively. Statistical analysis showed that K1 and K2 capsular serotypes were not significantly associated with ESBL phenotype (P=0.196). However, they were significantly associated with hypervirulent, as demonstrated by the positive string test (P<0.001). MLST analysis revealed that ST23 as the predominant sequence type (ST) in the K1 serotype, while the ST in the K2 serotype is more diverse. Conclusions: Although the occurrence of ESBL-producing isolates among the hypervirulent strains was low, their coexistence warrants the need for continuous surveillance. MLST showed that these isolates were genetically heterogeneous.