Prevalence and Molecular Genetics of Methicillin-Resistant Staphylococcus aureus Colonization in Nursing Homes in Saudi Arabia

Abstract

Objective. Methicillin-resistant Staphylococcus aureus (MRSA) is one of the main causative agents of nosocomial infections that has posed a major threat to those with compromised immune systems such as nursing home residents. The aim of this study was to determine the rates of MRSA strains and the types of Staphylococcal Cassette Chromosome mec (SCCmec)in nursing homes in Saudi Arabia. Methods. A total of 188 nasal swabs were collected from the residents and nursing staff in two nursing homes in Riyadh, Saudi Arabia. All MRSA isolates were tested for antimicrobial susceptibility and analyzed for mecA and SCCmec typing by multiplex PCR assay. Detection of the Panton–Valentine leukocidin (PVL) gene was also tested in all positive MRSA isolates by multiplex PCR using specific primers. Results. Among the 188 collected nasal swabs (105 males and 83 females), MRSA colonization rate was 9.04% (11 (5.85%) females and 6 (5.71%) males). About 47% of MRSA were multidrug resistant (MDR) as acquired resistance to beta-lactam, macrolide, and aminoglycoside antibiotics. However, all the MRSA isolates showed susceptibility to vancomycin, tigecycline, and linezolid. All the MRSA isolates (n = 17) were mecA-positive with the SCCmec IVc (n = 7, 41.18%) as the most common SCCmec type followed by SCCmec V (n = 5, 29.41%) and SCCmec IVa (n = 2, 11.76%). The remaining isolates (n = 3) were nontypeable (17.65%). In addition, the PVL toxin gene was only detected in four of the male samples. Conclusion. MRSA nasal colonization is a common incident among nursing home residents. The prevalence of community-associated (CA) MRSA (SCCmec IV and V) was more common than hospital-associated (HA) MRSA in our study samples. It is crucial to investigate such rate of incidence, which is a key tool in preventive medicine and would aid in determining health policy and predict emergent outbreaks.

mecA-gene detection and MDR profile of S. aureus isolates from patients attending the Referral Hospitals of Amhara Reginal state, Ethiopia

“…The MDR isolates observed in the current study was 87/110 (79.1%) which is in line with a previous report in Ethiopia, 65(82.3%) (15). However, the MDR S. aureus observed in the present study is higher than a previous study reported from Ethiopia where 98(50.5%) of the S. aureus were MDR (17); in Eritrea, 17/43(39.5%) (18); and in Saudi Arabia where 47% of MRSA were MDR (23).…”

“…As reported by Nwaogaraku et al from Nigeria showed that, all isolates of MRSA from blood samples of pigs were mecA negative on PCR (25). However, the present study is different from many studies done elsewhere (23,26,27). The possible explanation why phenotypically MRSA positive isolates did not show mecA gene might be due to loss of the mecA gene during prolonged storage (28) or other mechanisms other than the presence of mecA gene (mecC and mecB) responsible for methicillin resistant Staphylococcus aureus (29,30).…”

Molecular characteristics and risk factor analysis of Staphylococcus aureus colonization put insight into CC1 colonization in three nursing homes in Shanghai

“…Nursing homes increase MRSA transmission and infection risk as a result of admission of elderly residents with premorbid conditions and weakened immune systems [ 37 – 39 ]. The MRSA colonization rate among residents in this study (24/496, 4.8%) was much lower than that in other studies showing 9.0% in Belgium [ 40 ], 9.04% in Saudi Arabia [ 41 ], and 14.5% in Crete; in Greece [ 12 ], the colonization rate we observed was slightly higher than that in Brazil (3.7%) [ 13 ] which may differ by geographic location.…”

Regulation of virulence and β-lactamase gene expression in Staphylococcus aureus isolates: cooperation of two-component systems in bloodstream superbugs

“…In the current study, out of 61 MRSA strains, SCCmecI and SCCmec V, SCCmecII , SCCmecIII, and SCCmecIV genes were detected in 16.3, 22.9, 36.3, and 21.3% of isolates. This finding was also reported by some researchers from South Africa [ 16 ], Saudi Arabia [ 17 ], and Venezuela [ 18 ]. Surprisingly, none of the MSSA strains carried the VF genes.…”