The spread of multidrug-resistant Staphylococcus aureus is a public health concern. The inducible macrolide-lincosamide-streptogrammin B (iMLSB ) phenotype (or inducible clindamycin resistance) is associated with false clindamycin susceptibility in routine laboratory testing and may lead to treatment failure. Tigecycline resistance remains rare in S. aureus worldwide. This study aims to determine the antimicrobial susceptibility profiles of clinical isolates of S. aureus obtained from the main tertiary hospital in Terengganu state, Malaysia, from July 2016 to June 2017. The antimicrobial susceptibilities of 90 methicillin-resistant S. aureus (MRSA) and 109 methicillin-susceptible S. aureus (MSSA) isolates were determined by disc diffusion with the iMLSB phenotype determined by D-test. Multidrug resistance (MDR) and the iMLSB phenotype were more prevalent in MRSA (84.4 and 46.7 %, respectively) compared to MSSA isolates. All five tigecycline-resistant isolates were MRSA. The high incidence of MDR and the iMLSB phenotype and the emergence of tigecycline resistance in the Terengganu S. aureus isolates warrants continuous vigilance.
Staphylococcus hominis is a coagulase-negative Staphylococcus (CoNS) commensal capable of causing serious systemic infections in humans. The emergence of multidrug-resistant S. hominis strains is of concern but little is known about the characteristics of this organism, particularly from Malaysia. Here, we present the comparative genome analysis of S. hominis ShoR14, a multidrug-resistant, methicillin-resistant blood isolate from Terengganu, Malaysia. Genomic DNA of S. hominis ShoR14 was sequenced on the Illumina platform and assembled using Unicycler v0.4.8. ShoR14 belonged to sequence type (ST) 1 which is the most prevalent ST of the S. hominis subsp. hominis. Comparative genomic analysis with closely related strains in the database with complete genome sequences, led to the discovery of a novel variant of the staphylococcal chromosome cassette mec (SCCmec) type VIII element harboring the mecA methicillin-resistance gene in ShoR14 and its possible carriage of a SCCfus element that encodes the fusidic acid resistance gene (fusC). Up to seven possible ShoR14 plasmid contigs were identified, three of which harbored resistance genes for tetracycline (tetK), chloramphenicol (catA7), macrolides, lincosamides, and streptogramin B (ermC). Additionally, we report the discovery of a novel mercury-resistant transposon, Tn7456, other genomic islands, and prophages which make up the S. hominis mobilome.
Staphylococcus aureus is a common bacterial pathogen known to cause various kinds of infections due to its repertoire of virulence factors. This study aimed to investigate the distribution of 19 types of virulence genes among clinical isolates of methicillin-susceptible S. aureus (MSSA) using the polymerase chain reaction. A total of 109 MSSA isolates, i.e., 63 hospital-associated (HA) and 46 community-associated (CA) were collected from Hospital Sultanah Nur Zahirah, the main tertiary hospital in Terengganu, Malaysia, from July 2016 to June 2017. The most frequent virulence genes detected were hla (78.9%, n=86) and hld (78.0%, n=85) encoding hemolysins, lukED (56.9%, n=62) encoding leukotoxin ED, followed by seb (26.6%, n=29) and sea (24.8%, n=27) encoding enterotoxins. Among 34 (31.2%) isolates carrying six or more virulence genes, only five were multidrug resistant (MDR) while the remaining isolates were susceptible. Significant associations were discovered between the hld gene with CA-MSSA (p=0.016) and the seo gene with HA-MSSA (p=0.023). However, there is no significant association between virulence genes among the different types of infection. The clinical MSSA isolates in Terengganu showed high prevalence and high diversity of virulence gene carriage.
Despite the importance of methicillin-resistant Staphylococcus aureus (MRSA) as a priority nosocomial pathogen, the genome sequences of Malaysian MRSA isolates are currently limited to a small pool of samples. Here, we present the genome sequence analyses of 88 clinical MRSA isolates obtained from the main tertiary hospital in Terengganu, Malaysia in 2016-2020, to obtain in-depth insights into their characteristics. The EMRSA-15 (ST22-SCCmec IV) clone of the clonal complex 22 (CC22) lineage was predominant with a total of 61 (69.3%) isolates. Earlier reports from other Malaysian hospitals indicated the predominance of the ST239 clone, but only two (2.3%) isolates were identified in this study. Two Indian-origin clones, the Bengal Bay clone ST772-SCCmec V (n = 2) and ST672 (n = 10) were also detected, with most of the ST672 isolates obtained in 2020 (n = 7). Two new STs were found, with one isolate each, and were designated ST7879 and ST7883. From the core genome phylogenetic tree, the HSNZ MRSA isolates could be grouped into seven clades. Antimicrobial phenotype-genotype concordance was high (> 95%), indicating the accuracy of WGS in predicting most resistances. Majority of the MRSA isolates were found to harbor more than 10 virulence genes, demonstrating their pathogenic nature.