Methicillin-Resistant Staphylococcus aureus (MRSA) Clonal Replacement in a Malaysian Teaching Hospital: Findings from an Eight-Year Interval Molecular Surveillance

Abstract

Periodical surveillance on nosocomial pathogens is important for antimicrobial stewardship and infection control. The first methicillin-resistant Staphylococcus aureus (MRSA) molecular surveillance in Hospital Canselor Tuanku Muhriz (HCTM), a Malaysian teaching hospital, was performed in 2009. The dominant clone was identified as an MRSA carrying SCCmec type III-SCCmercury with ccrC and sea+cna toxin genes. In this study, we report the findings of the second HCTM MRSA surveillance carried out in 2017, after an interval of 8 years. Antibiotic susceptibility testing, SCCmec, toxin gene, and spa typing were performed for 222 MRSA strains isolated in 2017. Most strains were resistant to ciprofloxacin, erythromycin, clindamycin, cefoxitin, and penicillin (n = 126, 56.8%), belong to SCCmec type IV (n = 205, 92.3%), spa type t032 (n = 160, 72.1%) and harboured seg+sei toxin genes (n = 172, 77.5%). There was significant association between resistance of the aforementioned antibiotics with SCCmec type IV (p < 0.05), t032 (p < 0.001), and seg+sei carriage (p < 0.05). Results from this second MRSA surveillance revealed the occurrence of clonal replacement in HCTM during an interval of not more than 8 years. Investigation of the corresponding phenotype changes in this new dominant MRSA clone is currently on-going.

Multidrug-Resistant Methicillin-Resistant Staphylococcus aureus Associated with Hospitalized Newborn Infants

“…In 2018, a study reported the detection of MRSA spa type t032 from the community nasal swabs of healthy adults (11.1%, 2/18) in the same eastern coast state of Malaysia as this study (i.e., Terengganu), suggesting that this clone is likely circulating in communities without exposure to healthcare settings [ 47 ]. Recently, a high prevalence of spa type t032 in hospitalized patients was reported from two studies conducted in central Malaysia (72.1%, 160/222) and in Terengganu (39.3%, 35/89) [ 27 , 48 ]. Our preliminary WGS study of 62 clinical MDR-MRSA isolates revealed that the EMRSA-15 (ST22-SCC mec IV [2b]) clone (67.7%) and spa type t032 (50%) were indeed predominant (67.7%) in our local scenario [ 49 ].…”

Diversity and Dissemination of Methicillin-Resistant Staphylococcus aureus (MRSA) Genotypes in Southeast Asia

“…Indeed, a recent report from 2016 to 2017 of MRSAs isolated from Kelantan, a state located at the north of Peninsular Malaysia just across the border from Thailand, revealed that majority of MRSA isolates were ST22 (68.2%), followed by ST239 (29.5%) [45]. Another molecular surveillance in a teaching hospital, Hospital Canselor Tuanku Muhriz (HCTM), conducted in 2017, reported clonal replacement of the previous dominant MRSA clone of SCCmec type III-SCCmercury (these clones were also found to carry sea+cna) with SCCmec type IV (which carried seg + sei) after an eight-year interval from the first molecular surveillance carried out in the hospital in 2009 [44,46]. This clonal replacement phenomenon has been observed in many countries, such as Singapore, the United States, and Germany [25,47,48].…”

Dissemination Pattern of Hospital-Acquired Methicillin-Resistant Staphylococcus aureus and Community-Acquired MRSA Isolates from Malaysian Hospitals: A Review from a Molecular Perspective

“…Most studies involving Malaysian clinical isolates inferred that ST239-SCC mec type III is the most circulating clone in the hospital setting ( 10 , 24 , 29 , 30 , 33 , 37 , 38 ). ST239-III is a single-locus variant of ST8 found to be the predominant clone in most Asian countries, including from neighbouring countries such as Indonesia, Lao People’s Democratic Republic, Vietnam and Thailand ( 39 – 43 ).…”

“…In a study involving MRSA clinical isolates in 2014 and 2015, ST22-IV was the most prevalent clone identified instead of ST239-III ( 23 ). However, a more recent study found that SCC mec IV and t032 predominated the MRSA isolates in 2017 ( 24 ). Based on the spa -typing database ( https://www.spaserver.ridom.de/ ), the MLST of the t032 is found to be ST22.…”