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. 2018 Mar 15;17(1):7.
doi: 10.1186/s12941-018-0260-2.

Comparative and molecular analysis of MRSA isolates from infection sites and carrier colonization sites

Khaled R Alkharsah  1   2 , Suriya Rehman  3 , Fatimah Alkhamis  3 , Amani Alnimr  4 , Asim Diab  4 , Amein K Al-Ali  5
Affiliations

Comparative and molecular analysis of MRSA isolates from infection sites and carrier colonization sites

Khaled R Alkharsah et al. Ann Clin Microbiol Antimicrob. .

Abstract

Background: Methicillin resistant Staphylococcus aureus (MRSA) constitutes a major global health concern causing hospital and community acquired infections. A wide diversity of MRSA genotypes are circulating in geographically related regions. Therefore understanding the molecular epidemiology of MRSA is fundamental to design control and clearance measures.

Methods: A total of 106 MRSA isolates from infection (51) and carrier colonization sites (55) are characterized genetically based on SCCmec and MLST genotyping methods in addition to detection of PVL, TSST-1 and enterotoxins.

Results: Sccmec-IV was the most frequently detected genotype (77.3%) followed by genotype V (13.2%) and III (9.4%). SCCmec-IVa was more prevalent among the carrier group (p value 0.002). CC80 was the most commonly identified clonal complex (CC). CC6 and CC22 were significantly more prevalent among the carrier group (p value 0.02 and 0.01, respectively). PVL was highly prevalent among the isolates (58.5%). PVL was detected in 70.6% of isolates from infection sites and 47.3% of isolates from carriers. All strains were sensitive to vancomycin, however, MRSA strains isolated from infection sites had significantly higher MICs compared to strains isolated from carrier colonization sites (p value 0.021). Five new sequence types mainly from the carrier group were identified and described in the study.

Conclusions: MRSA population is genetically very diverse among carriers and infected individuals. With SCCmec type IV being most prevalent, this suggests a community origin of most MRSA strains. Therefore very well designed surveillance and clearance strategies should be prepared to prevent emergence and control spread of MRSA in the community.

Keywords: CA-MRSA; Carrier; HA-MRSA; Infection; MLST; MRSA; SCCmec; Saudi Arabia.

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Figures

Fig. 1
Fig. 1
Phylogenetic analysis of the MRSA MLST-genotypes and their frequency among carrier and infection groups. 7 new types are not included in the analysis
See this image and copyright information in PMC

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