Beta hemolysin gene of Staphylococcus phage 3AJ_2017 genome is a suitable molecular marker for identification and characterization of pathogenic Staphylococcus aureus

Abstract

Background Staphylococcus aureus cause diseases both in humans and animals. These diseases range from mild to fatal infections thus necessitating development of a specific molecular method for detection of pathogenic S. aureus. Objectives To identify and analyze genetic profile of pathogenic S. aureus using bacteriophage based genetic biomarkers. Methods Using culture and biochemical methods, 148 S. aureus (87 %) were isolated from 170 raw milk samples taken from 10 dairy farms in Marsabit and Isiolo counties in Northern Kenya between June 2016 and February 2017. The samples were collected directly from dairy lactating cows previously diagnosed with S. aureus in a follow‐up study. The isolates were analyzed by PCR and sequencing of beta hemolysin (hlb) gene. The genetic relationship between five Kenyan S. aureus isolates and five isolates previously identified was inferred. Results From the 96 isolates screened for hlb gene, 75 (78.1%) tested positive. Some of the positive isolates yielded a band size of 975 bp, while others 1100 bp. Through Basic Local Alignment Search Tool (BLAST) search analysis, the two different band sizes (975 bp and 1100 bp) were both confirmed to be hlb gene from S. aureus isolates indicating that the difference in band size may have been due to deletions that were detected in the 975 bp hlb gene. Some S. aureus isolates from Kenya appeared to be closely related to isolates from other parts of the world, while some showed a distant relationship. Conclusions Phage‐derived hlb gene is a suitable molecular marker for detection of pathogenic S. aureus.

Distribution of hla, hlb, hlgC, hld & cylA hemolysin genes and their alleles in different bacterial species isolated from the variant clinical sources in Basrah

“…As a result of genetic transfer, whether via mobile genetic transfer or recombination, perhaps that will provide a way for bacterial species in general to adapt to their surrounding environment. This results in non-specific hlb for S. aureus, which interferes with using the phage-derived hlb gene as a marker and has a significant impact on S. aureus identification (Miruka et al, 2022). Importantly, the comparison among alleles in the present study were refer to the differences more than identities, because the present study didn't produce a complete sequence for all comparing gene.…”

“…Beta hemolysin is a virulence factor in S. aureus (Glenny and Stevens, 1935). It is sphingomyelinase encoded by the hlb and breakdown many types of cells as lymphocytes, keratinocytes, and neutrophils based on the content of sphingomyelin (Rees and Barr , 2017; Miruka et al, 2022). Gamma hemolysin is a poreforming toxin produced by S. aureus that lyse the white and red blood cells.…”