Characterisation of the Virulence Factors and Genetic Types of Methicillin Susceptible Staphylococcus aureus from Patients and Healthy Individuals

Lim, King Ting; Hanifah, Yasmin Abu; Yusof, Mohd Yasim Mohd; Thong, Kwai Lin

doi:10.1007/s12088-012-0286-7

Cited by 15 publications

(16 citation statements)

References 28 publications

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“…Furthermore, the 21 MSSA strains were also grouped into 8 different MLST-spa types. This indicated that the MSSA strains were more genetically diverse than the MRSA strains, which is in agreement with other reports that MSSA strains were more diversely distributed and highly heterogeneous as compared with MRSA strains (17,39,40).…”

Section: Discussionsupporting

confidence: 92%

Comparison of Methicillin-Resistant and Methicillin-Sensitive Staphylococcus aureus Strains Isolated from a Tertiary Hospital in Terengganu, Malaysia

et al. 2012

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SUMMARY: Staphylococcus aureus is a persistent human pathogen responsible for a variety of infections ranging from soft-tissue infections to bacteremia. The objective of this study was to determine genetic relatedness between methicillin-resistant S. aureus (MRSA) and methicillin-susceptible S. aureus (MSSA) strains. We isolated 35 MRSA and 21 MSSA strains from sporadic cases at the main tertiary hospital in Terengganu, Malaysia, screening them for the presence of virulence genes. Their genetic relatedness was determined by accessory gene regulator (agr) types, PCR-restriction fragment length polymorphism (RFLP) of the coa gene, pulsed-field gel electrophoresis (PFGE), S. aureus protein A (spa), and multilocus-sequence typing (MLST). We found that 57z of MRSA and 43z of MSSA strains harbored enterotoxin genes. The majority (87.5z) of the strains were agr type I. PCR-RFLP and PFGE genotyping of the coa gene revealed that MRSA strains were genetically related, whereas MSSA strains had higher heterogeneity. The combined genotype, MLST-spa type ST239-t037, was shared among MRSA and MSSA strains, indicating that MRSA strains could have evolved from MSSA strains. Two combined MLST-spa types were present in MRSA strains, whereas 7 different MLST-spa types were detected in MSSA strains, including 2 combined types (ST779-t878 and ST1179-t267) that have not been reported in Malaysia. In conclusion, enterotoxin genes were more prevalent in MRSA than in MSSA strains in the Terengganu hospital. The MSSA strains were genetically more diverse than the MRSA strains.

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Section: Discussionsupporting

confidence: 92%

Comparison of Methicillin-Resistant and Methicillin-Sensitive Staphylococcus aureus Strains Isolated from a Tertiary Hospital in Terengganu, Malaysia

et al. 2012

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“…The MSSA strains were previously confirmed by BBL Staphyloslide-Latex Test (BD, USA) [17] while MRSA strains were confirmed by standard biochemical tests [16] with minor modifications. In brief, all MRSA strains were streaked on blood and mannitol salt agars and incubated overnight at 35°C.…”

Section: Methodsmentioning

confidence: 99%

Loop-Mediated Isothermal Amplification Assay for the Rapid Detection ofStaphylococcus aureus

Lim

Teh

Thong

2013

BioMed Research International

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Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA), is an important human pathogen that produces a variety of toxins and causes a wide range of infections, including soft-tissue infections, bacteremia, and staphylococcal food poisoning. A loop-mediated isothermal amplification (LAMP) assay targeting the arcC gene of S. aureus was developed and evaluated with 119 S. aureus and 25 non-S. aureus strains. The usefulness of the assay was compared with the PCR method that targets spa and arcC genes. The optimal temperature for the LAMP assay was 58.5°C with a detection limit of 2.5 ng/μL and 102 CFU/mL when compared to 12.5 ng/μL and 103 CFU/mL for PCR (spa and arcC). Both LAMP and PCR assays were 100% specific, 100% sensitive, 100% positive predictive value (PPV), and 100% negative predictive value (NPV). When tested on 30 spiked blood specimens (21 MRSA, eight non-S. aureus and one negative control), the performance of LAMP and PCR was comparable: 100% specific, 100% sensitive, 100% PPV, and 100% NPV. In conclusion, the LAMP assay was equally specific with a shorter detection time when compared to PCR in the identification of S. aureus. The LAMP assay is a promising alternative method for the rapid identification of S. aureus and could be used in resource-limited laboratories and fields.

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“…mPCR approach is useful to detect several short-sequenced genes of interest in one single reaction. It has been performed by many researchers in laboratories due to its high sensitivity and specificity [13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Comparative Virulotyping of Salmonella typhi and Salmonella enteritidis

Elemfareji

Thong

2013

Indian J Microbiol

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Members of Salmonella enterica are important foodborne pathogens of significant public health concern worldwide. This study aimed to determine a range of virulence genes among typhoidal (S. typhi) and non-typhoidal (S. enteritidis) strains isolated from different geographical regions and different years. A total of 87 S. typhi and 94 S. enteritidis strains were tested for presence of 22 virulence genes by employing multiplex PCR and the genetic relatedness of these strains was further characterized by REP-PCR. In S. typhi, invA, prgH, sifA, spiC, sopB, iroN, sitC, misL, pipD, cdtB, and orfL were present in all the strains, while sopE, agfC, agfA, sefC, mgtC, and sefD were present in 98.8, 97.7, 90.8, 87.4, 87.4 and 17.2 %, of the strains, respectively. No lpfA, lpfC, pefA, spvB, or spvC was detected. Meanwhile, in S. enteritidis, 15 genes, agfA, agfC, invA, lpfA, lpfC, sefD, prgH, spiC, sopB, sopE, iroN, sitC, misL, pipD, and orfL were found in all S. enteritidis strains 100 %, followed by sifA and spvC 98.9 %, pefA, spvB and mgtC 97.8 %, and sefC 90.4 %. cdtB was absent from all S. enteritidis strains tested. REP-PCR subtyped S. typhi strains into 18 REP-types and concurred with the virulotyping results in grouping the strains, while in S. enteritidis, REP-PCR subtyped the strains into eight profiles and they were poorly distinguishable between human and animal origins. The study showed that S. typhi and S. enteritidis contain a range of virulence factors associated with pathogenesis. Virulotyping is a rapid screening method to identify and profile virulence genes in Salmonella strains, and improve an understanding of potential risk for human and animal infections.

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Characterisation of the Virulence Factors and Genetic Types of Methicillin Susceptible Staphylococcus aureus from Patients and Healthy Individuals

Cited by 15 publications

References 28 publications

Comparison of Methicillin-Resistant and Methicillin-Sensitive Staphylococcus aureus Strains Isolated from a Tertiary Hospital in Terengganu, Malaysia

Comparison of Methicillin-Resistant and Methicillin-Sensitive Staphylococcus aureus Strains Isolated from a Tertiary Hospital in Terengganu, Malaysia

Loop-Mediated Isothermal Amplification Assay for the Rapid Detection ofStaphylococcus aureus

Comparative Virulotyping of Salmonella typhi and Salmonella enteritidis

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