Comparison of Methicillin-Resistant and Methicillin-Sensitive Staphylococcus aureus Strains Isolated from a Tertiary Hospital in Terengganu, Malaysia

Abstract

SUMMARY: Staphylococcus aureus is a persistent human pathogen responsible for a variety of infections ranging from soft-tissue infections to bacteremia. The objective of this study was to determine genetic relatedness between methicillin-resistant S. aureus (MRSA) and methicillin-susceptible S. aureus (MSSA) strains. We isolated 35 MRSA and 21 MSSA strains from sporadic cases at the main tertiary hospital in Terengganu, Malaysia, screening them for the presence of virulence genes. Their genetic relatedness was determined by accessory gene regulator (agr) types, PCR-restriction fragment length polymorphism (RFLP) of the coa gene, pulsed-field gel electrophoresis (PFGE), S. aureus protein A (spa), and multilocus-sequence typing (MLST). We found that 57z of MRSA and 43z of MSSA strains harbored enterotoxin genes. The majority (87.5z) of the strains were agr type I. PCR-RFLP and PFGE genotyping of the coa gene revealed that MRSA strains were genetically related, whereas MSSA strains had higher heterogeneity. The combined genotype, MLST-spa type ST239-t037, was shared among MRSA and MSSA strains, indicating that MRSA strains could have evolved from MSSA strains. Two combined MLST-spa types were present in MRSA strains, whereas 7 different MLST-spa types were detected in MSSA strains, including 2 combined types (ST779-t878 and ST1179-t267) that have not been reported in Malaysia. In conclusion, enterotoxin genes were more prevalent in MRSA than in MSSA strains in the Terengganu hospital. The MSSA strains were genetically more diverse than the MRSA strains.

Distribution of Adhesion and Toxin Genes in Staphylococcus aureus Strains Recovered From Hospitalized Patients Admitted to the ICU

“…In the present study, the incidence rate of the eta gene was higher than that reported in other studies from Iran 0.68% (12), Colombia (3%) (29), and Malaysia (0%) (6). Unlike the results of the present study, high prevalence of the eta gene was reported in studies conducted in Czech (10%) (5) and Turkey 19.2% (32).…”

“…The most prevalent toxin gene was found to be tst, with a prevalence rate of 51.4%, which is higher than that reported in previous studies conducted in Iran (11.6%) (12), Sweden (22%) (28), Malaysia (0.5%) (6) and Colombia (10%) (29). An interesting finding in the present study is that Arch Pediatr Infect Dis.…”

“…These results are in line with those of other studies which reported high frequency of the tst gene in MRSA strains isolated from blood and wound samples (12). However, a study in Malaysia (6) found that the tst gene was only isolated from respiratory samples. Community acquired-MRSA (CA-MRSA) may be more virulent than hospital acquired-MRSA (HA-MRSA) (7).…”

“…The most common cause of biofilm formation is adhesion proteins. Several types of cell wall-associated adhesion proteins have been reported, namely fnb, which encodes fibronectin-binding protein; cna, which encodes collagen-binding protein; clf, which encodes clumping factor; and ebp, elastin-binding protein (5)(6)(7). TST-1 can cause toxic shock syndrome and ETs cause peeling skin syndrome.…”

Comparative Exoproteomics and Host Inflammatory Response in Staphylococcus aureus Skin and Soft Tissue Infections, Bacteremia, and Subclinical Colonization

“…In the limited number of isolates studied, we were not able to define any specific correlation between clones and disease types. Although two studies have reported that no single staphylococcal genotype is specifically associated with a defined infection type (32,33), two other studies have shown CC5 and CC30 to be associated with infectious endocarditis and osteomyelitis (34,35).…”