Characterization of β-lactam resistance in K. pneumoniae associated with ready-to-eat processed meat in Egypt

Abstract

K. pneumoniae was known as a nosocomial infection that causes human diseases. It is considered as one of the food-borne pathogens as it causes septicemia and diarrhea in humans. This study aims to characterize K. pneumoniae strains isolated from ready to eat processed meat phenotypically and genetically. Three hundred and fifty ready to eat processed meat (Luncheon-meat) samples were collected. Forty-four (12.6%) K. pneumoniae strains were isolated and bio-typed, where the majority were identified to belong to biotype B1. K1 and K2 serotypes were detected and strains were classified as hypermucoviscous K. pneumoniae (HVKP) and classic K. pneumoniae (CKP) (26 and 18 isolates, respectively). The isolates were resistant to several classes of β-lactam antibiotics, ceftazidim and cefotaxime (95.5%), cefoxitin (93.2%), ertapenem (90.9%) and amoxicillin-clavulanic acid (86.4%). They were classified as extended spectrum β-lactamases (ESBLs), AmpC or carbapenemase-producers phenotypically. Eighteen β-lactamase genes were investigated by PCR. The most prominent genes were SHV (63.6%), TEM (52.2%), CTX-M15 (50%), AMPC (47.7%), CIT-M (45.5%) and VIM (43.2%). Co-detection of β-lactam resistance genes revealed 42 gene profiles. Twenty-four isolates had the complete efflux system (AcrAB-ToƖC). Besides, Integrons (I, II, III) were detected in 20 isolates. Molecular typing by ERIC-PCR showed high genetic diversity between isolates as 34 different patterns were identified. Overall, this study confirmed the hazards posed by the presence of multiple resistance genes in the same isolate and this should not be undervalued. Besides, the horizontal transfer of plasmid harboring resistance genes between isolates in food represents potential health risks for consumers in Egypt and so the control and inhibition plans are necessary.

Fig 1. Genotyping of K. pneumoniae isolates using ERIC-PCR method.

The dendrogram was constructed using ERIC-PCR patterns of K. pneumoniae isolates. Similarity clustering analysis was performed using the UPGMA and Dice coefficient. The dashed line is a hypothetical line showing 85% similarity. Biotyping, serodiagnosis, hypermucoviscosity, ESBL-producers, AmpC-producers, Carbapenemase-producers, efflux system, integrons, and genes profile among K. pneumoniae isolates were reported. B: biotype, CKP: classical K. pneumoniae, HVKP: hypermucoviscous K. pneumoniae, U: untypable, Pr: profile, ERIC-PCR, enterobacterial repetitive intergenic consensus-PCR. UPGMA, unweighted-pair group method with arithmetic averages.