Entero- and exfoliative toxin gene profiling of 237 methicillin-susceptible Staphylococcus aureus (MSSA) isolated from Universiti Kebangsaan Malaysia Medical Centre (UKMMC) were carried out via PCR amplification. Among the tested toxin genes, sei was found to be the most prevalent (54.9%)

Hassriana Fazilla Sapri,

Neoh, Hui-min

Rahman Jamal,

Saberi Saimun,

Salasawati Hussin,

UKM Journal Article Repository

Asia-Pacific Journal of Mol. Medicine 2017, 7(2):1 1 Correspondence to : hui-min@ppukm.ukm.edu.my  Text Methicillin-resistant Staphylococcus aureus (MRSA) garners more research attention rather than  methicillin-susceptible S. aureus (MSSA), due to the fact that MRSA are usually found to be multidrug resistant and hence complicate treatment options [1, 2]. Nevertheless, in a study on S. aureus isolated from our medical centre, a four-toxin gene (collagen adhesion-encoding gene (cna), staphylococcal enterotoxin h (seh), Panton-Valentine Leukocidin (PVL) and Toxic Shock Syndrome Toxin (TSST-1)) profiling study revealed a higher prevalence of these genes in MSSA isolates compared to MRSAs isolated during the same period [3]. Staphylococcal entero- and exfoliative toxin genes are important virulent factors of the bacteria associated with food poisoning and staphylococcal scalded skin syndrome (SSSS), respectively [4]. In addition, staphylococcal toxin gene profiling is also important as a tool for molecular epidemiological studies [4]. In this study, we determined the prevalence of seven staphylococcal enterotoxins (sea, seb, sec, sed, see, seg, sei) and two exfoliative toxin genes (eta, etb) in MSSAs isolated from UKM Medical Centre (UKMMC) in 2009.  A total of 237 MSSA infections were recorded in UKMMC in 2009. The first MSSA isolate of each infection was included into the study. Chromosomal DNA of the MSSA strains were extracted using a DNeasy Blood & Tissue Kit (Qiagen, Valencia, CA). Toxin gene profiling was carried out using primers and cycling conditions as described previously [5, 6]. Amplification of toxin genes for all strains was carried out using a Bio-rad MyCyclerTM, PCR products were electrophoresed on a 1% agarose gel and stained with Lonza GelStar™ Nucleic Acid Gel Stain (Thermo Fisher Scientific Inc.) for band visualization.  Results of the toxin gene profiling are listed in Table 1. More than half (181 strains, 76.4%) of the MSSA tested in our study carried at least one toxin gene, where sei was found to be the most prevalent toxin gene detected (54.9%). Most strains carried the seg + sei combination (96 strains, 40.5%). seg-sei toxin genes are clustered as the enterotoxin gene cluster (egc), which comprises the seg-sei-sem-sen-seo and sometimes seu genes [7]. Interestingly, our study strains did not harbour the sed or see genes. On the other hand, the prevalence of eta and etb genes was found to be low in our study strains. Only 4 strains (1.7%) harboured eta, while prevalence of etb was slightly higher (23 strains, 9.7%). A total of 56 (23.6%) strains did not harbour any toxin genes.  Reports on toxin gene profiling of Malaysian MSSA strains remains limited; as far as we know, only 3 reports on this subject have been published [8, 9, 10]. Two of these reports involved MSSA strains isolated from Hospital Kuala Lumpur (HKL) and University Malaya Medical Centre (UMMC), respectively [8, 9]. These two hospitals are located at the central region of the west coast of Peninsular Malaysia. The third study was conducted on MSSAs isolated from Terengganu, a state located at the East Coast of Peninsular Malaysia [10].  Prevalence of the seg and sei genes in our strains (41.8% and 54.9%, respectively) were comparable to that of MSSAs isolated from HKL (36.5% and 36.9%,  Toxin gene profiling of methicillin-susceptible Staphylococcus aureus (MSSA) isolated from a Malaysian teaching hospital  1Hui-min Neoh*, 1Saberi Saimun, 2Hassriana Fazilla Sapri, 2Salasawati Hussin, 1Rahman Jamal  1 UKM Medical Molecular Biology Institute, Universiti Kebangsaan Malaysia, Malaysia 2 Department of Medical Microbiology and Immunology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Malaysia  Received on 24/02/2016 / Accepted on 24/12/2017  Abstract  Entero- and exfoliative toxin gene profiling of 237 methicillin-susceptible Staphylococcus aureus (MSSA) isolated from Universiti Kebangsaan Malaysia Medical Centre (UKMMC) were carried out via PCR amplification. Among the tested toxin genes, sei was found to be the most prevalent (54.9%).  Asia-Pacific Journal of Mol. Medicine 2017, 7(2):1 2 Correspondence to : hui-min@ppukm.ukm.edu.my  respectively), which is one of the largest public hospitals in Malaysia [8]. Nevertheless, our MSSA strains had a higher prevalence of sea (49.4%), seb (30.0%) and sec (23.2%) compared to the UMMC (sea – 13.4%, seb – 4.5%, sec – 16.4%) and HKL (sea – 24.2%, seb – 23.8%, sec – 11.9%) [8, 9] strains. Intriguingly, the seg-sei genes were not detected in MSSAs isolated from Terengganu [10], even though these genes were commonly found in the central West Peninsular Malaysia MSSAs [8, 9]. Interestingly, even though its prevalence was only 28.6%, the sea gene was the most dominant toxin gene detected in the Terengganu’s MSSAs. The sed and see genes seemed to be rare in Malaysian MSSA strains as they were not detected in previous studies as well as in our study [8, 9, 10]. The prevalence of the eta (1.7%) and etb (9.7%) exfoliative genes in our study strains was slightly lower and higher, respectively, compared to the HKL study (eta = 2.3%, etb = 0.8%) [8]. On the other hand, no eta or etb gene was detected in the UMMC study [9]. Similarly, these genes were also not found in the Terengganu study isolates [10].    As a summary, MSSA strains of this study and those isolated from the central region of West Peninsular Malaysia appeared to have a more similar toxin gene profile compared to MSSAs from East Peninsular Malaysia. More toxin gene profiling studies, especially for MSSA isolates from the northern or southern states of Peninsular Malaysia, together with East Malaysia (Borneo), will provide a more complete Table 1: Toxin gene profiles of MSSA strains used in this study.Toxin gene profile n (%) Toxin gene n (prevalence, %)sea 31 (13.1) sea 117 (49.4)sea + seb 7 (3.0) seb 71 (30.0)seb 2 (0.8) sec 55 (23.2)sea + sec 4 (1.7) sed 0 (0)sec 3 (1.3) see 0 (0)seg 2 (0.8) seg 99 (41.8)sea + seb + seg 1 (0.4) sei 130 (54.9)sea + sei 8 (3.4) eta 4 (1.7)sei 8 (3.4) etb 23 (9.7)sea + seb + sei 7 (3.0)seb + sei 5 (2.1)sea + sec + sei 2 (0.8)sea + seb +sec + sei 1 (0.4)seb +sec + sei 1 (0.4)sea + seg + sei 6 (2.5)seg + sei 13 (5.5)sea + seb + seg + sei 14 (5.9)seb + seg + sei 7 (3.0)sea + sec + seg + sei 14 (5.9)sec +seg +sei 7 (3.0)sea + seb +sec + seg +sei 6 (2.5)seb + sec + seg + sei 6 (2.5)seg + sei + eta 3 (1.3)sec + seg + sei + eta 1 (0.4)sea + etb 1 (0.4)etb 1 (0.4)sea + sei + etb 1 (0.4)sea + seb + sei +etb 1 (0.4)sea + seg + sei + etb 3 (1.3)seg + sei + etb 1 (0.4)sea + seb + seg + sei + etb 5 (2.1)sea + sec + seg + sei + etb 1 (0.4)sec + seg + sei + etb 1 (0.4)sea + seb + sec + seg + sei + etb 4 (1.7) seb + sec + seg + sei + etb 4 (1.7)no toxin gene 56 (23.6)Hui-min Neoh et al.                     Asia. Pac. J. Mol. Med 3  picture of the molecular epidemiology of MSSA in Malaysia.  Acknowledgement  The authors wish to thank medical laboratory technicians in the Bacteriology Unit, Medical Microbiology and Immunology Department, UKM Medical Centre. This study was funded by UKM Research University Grant UKM-GUP-TKP-08-19-067 and Pusat Perubatan UKM Fundamental Grant (Category B) FF-001-2012.  References  1. Holmes NE, Howden BP. What's new in the treatment of serious MRSA infection? Curr Opin Infect Dis 2014; 27:471-8. 2. Holland TL, Arnold C, Fowler VG Jr. Clinical management of Staphylococcus aureus bacteremia: a review. JAMA 2014; 312(13):1330-41. 3. Sapri HF, Sani NA, Neoh HM, Hussin S. Epidemiological Study on Staphylococcus aureus Isolates Reveals Inverse Relationship between Antibiotic Resistance and Virulence Repertoire. Indian J Microbiol 2013; 53(3):321-2. 4. Xie Y, He Y, Gehring A, Hu Y, Li Q, et al. Genotypes and Toxin Gene Profiles of Staphylococcus aureus Clinical Isolates from China. PLoS ONE 2011; 6(12): e28276. 5. Jarraud S, Mougel C, Thioulouse J, Lina G, Meugnier H, Forey F, Nesme X, Etienne J, Vandenesch F. Relationships between Staphylococcus aureus Genetic Background, Virulence Factors, agr Groups (Alleles), and Human Disease. Infect Immun 2002; 70: (2): 631-641. 6. Lina G, Piémont Y, Godail-Gamot F, Bes M, Peter M, Gauduchon V, Vandenesch F, Etienne J. Involvement of Panton-Valentine Leukocidin—Producing Staphylococcus aureus in Primary Skin Infections and Pneumonia. Clin Infect Dis 1999; 29(5): 1128-1132. 7. Lindsay JA, Holden MT. Understanding the rise of the superbug: investigation of the evolution and genomic variation of Staphylococcus aureus. Funct Integr Genomic 2006; 6: 186–201. 8. Ghasemzadeh-Moghaddam H, Ghaznavi-Rad E, Sekawi Z, Yun-Khoon L, Aziz MN, Hamat RA, Melles DC, van Belkum A, Shamsudin MN, Neela V. Methicillin-susceptible Staphylococcus aureus from clinical and community sources are genetically diverse. Int J Med Microbiol 2011; 301(4):347-53.  9. Lim KT, Abu Hanifah Y, Mohd Yusof MY, Thong KL. Characterisation of the Virulence Factors and Genetic Types of Methicillin Susceptible Staphylococcus aureus from Patients and Healthy Individuals. Indian J Microbiol 2012; 52(4):593–600. 10. Lim KT, Yeo CC, Suhaili Z, Thong KL. Comparison of methicillin-resistant and methicillin-sensitive Staphylococcus aureus strains isolated from a tertiary hospital in Terengganu, Malaysia. Jpn J Infect Dis 2012;65(6):502-9.    

Toxin gene profiling of methicillin-susceptible Staphylococcus aureus (MSSA) isolated from a Malaysian teaching hospital

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Toxin gene profiling of methicillin-susceptible Staphylococcus aureus (MSSA) isolated from a Malaysian teaching hospital

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