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Sapri HF, Ismail MAH, Sani NAM, Noordin A, Tan TL, Hussin S, Neoh HM. Molecular surveillance of methicillin-susceptible Staphylococcus aureus (MSSA) isolated over a one-year period from a Malaysian Teaching Hospital. Germs 2020; 10:104-111. [PMID: 32656107 DOI: 10.18683/germs.2020.1191] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 05/19/2020] [Accepted: 05/31/2020] [Indexed: 11/08/2022]
Abstract
Introduction We report the results of a molecular surveillance study carried out on methicillin-susceptible Staphylococcus aureus (MSSA) isolated in a one-year duration from Hospital Canselor Tuanku Muhriz (HCTM), a tertiary hospital located in Kuala Lumpur, Malaysia. Methods The first strain isolated from each MSSA infection in HCTM during the year 2009 was included into the study. Antimicrobial susceptibility testing and agr group typing were carried out for all strains; virulence gene (cna, seh, TSST-1 and PVL) typing results of the strains were obtained from a previous study. Pulsed-field gel electrophoresis (PFGE) was done on selected strains from the orthopedic ward. Relationship(s) between different typing methods used in the study was investigated, where a p value of <0.05 indicated significant association between typing methods. Results A total of 880 MSSA strains were included into the study. The strains were generally susceptible to most antibiotics, with most of them carrying cna and agr-I (51.6%, n=454; 39.8%, n=350, respectively). A total of 17 PFGE pulsotypes were identified using an 80% similarity cut-off value, where the main pulsotype (pulsotype E) consisted of 24 isolates (23.5%). agr-III strains were found to be usually positive for both cna and seh (p<0.05). In addition, some PFGE pulsotypes were also characteristic of certain virulence genes or agr groups. Conclusions We did not identify a dominant MSSA clone circulating in HCTM in 2009. Nevertheless, results from this molecular surveillance will provide good baseline data for the hospital's second S. aureus surveillance planned for the year 2020.
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Affiliation(s)
- Hassriana Fazilla Sapri
- PhD, Department of Medical Microbiology and Immunology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Cheras, 56000 Kuala Lumpur, Malaysia
| | - Mohd Azrul Hisham Ismail
- MSc, UKM Medical Molecular Biology Institute (UMBI), Universiti Kebangsaan Malaysia, Cheras, 56000 Kuala Lumpur, Malaysia
| | - Nurul Azirah Mohamad Sani
- PhD, Department of Medical Microbiology and Immunology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Cheras, 56000 Kuala Lumpur, Malaysia
| | - Ainihayati Noordin
- MSc, Department of Medical Microbiology and Immunology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Cheras, 56000 Kuala Lumpur, Malaysia
| | - Toh Leong Tan
- MD, DrEmMed, Department of Emergency Medicine, Faculty of Medicine, Universiti Kebangsaan Malaysia, Cheras, 56000 Kuala Lumpur, Malaysia
| | - Salasawati Hussin
- MD, MPath; Department of Medical Microbiology and Immunology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Cheras, 56000 Kuala Lumpur, Medical Science Division, Faculty of Medicine, University of Cyberjaya, Cyberjaya, 63000, Selangor, Malaysia
| | - Hui-Min Neoh
- PhD, UKM Medical Molecular Biology Institute (UMBI), Universiti Kebangsaan Malaysia, Cheras, 56000 Kuala Lumpur, Malaysia
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Choudhary KS, Mih N, Monk J, Kavvas E, Yurkovich JT, Sakoulas G, Palsson BO. The Staphylococcus aureus Two-Component System AgrAC Displays Four Distinct Genomic Arrangements That Delineate Genomic Virulence Factor Signatures. Front Microbiol 2018; 9:1082. [PMID: 29887846 PMCID: PMC5981134 DOI: 10.3389/fmicb.2018.01082] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 05/07/2018] [Indexed: 01/24/2023] Open
Abstract
Two-component systems (TCSs) consist of a histidine kinase and a response regulator. Here, we evaluated the conservation of the AgrAC TCS among 149 completely sequenced Staphylococcus aureus strains. It is composed of four genes: agrBDCA. We found that: (i) AgrAC system (agr) was found in all but one of the 149 strains, (ii) the agr positive strains were further classified into four agr types based on AgrD protein sequences, (iii) the four agr types not only specified the chromosomal arrangement of the agr genes but also the sequence divergence of AgrC histidine kinase protein, which confers signal specificity, (iv) the sequence divergence was reflected in distinct structural properties especially in the transmembrane region and second extracellular binding domain, and (v) there was a strong correlation between the agr type and the virulence genomic profile of the organism. Taken together, these results demonstrate that bioinformatic analysis of the agr locus leads to a classification system that correlates with the presence of virulence factors and protein structural properties.
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Affiliation(s)
- Kumari S Choudhary
- Systems Biology Research Group, Department of Bioengineering, University of California, San Diego, San Diego, CA, United States
| | - Nathan Mih
- Systems Biology Research Group, Department of Bioengineering, University of California, San Diego, San Diego, CA, United States.,Bioinformatics and Systems Biology Program, University of California, San Diego, San Diego, CA, United States
| | - Jonathan Monk
- Systems Biology Research Group, Department of Bioengineering, University of California, San Diego, San Diego, CA, United States
| | - Erol Kavvas
- Systems Biology Research Group, Department of Bioengineering, University of California, San Diego, San Diego, CA, United States
| | - James T Yurkovich
- Systems Biology Research Group, Department of Bioengineering, University of California, San Diego, San Diego, CA, United States.,Bioinformatics and Systems Biology Program, University of California, San Diego, San Diego, CA, United States
| | - George Sakoulas
- Department of Pediatrics, University of California, San Diego, San Diego, CA, United States
| | - Bernhard O Palsson
- Systems Biology Research Group, Department of Bioengineering, University of California, San Diego, San Diego, CA, United States.,Bioinformatics and Systems Biology Program, University of California, San Diego, San Diego, CA, United States.,Department of Pediatrics, University of California, San Diego, San Diego, CA, United States
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Hematian A, Monjezi A, Abiri R, Mohajeri P, Farahani A, Soroush S, Taherikalani M. Clonal Lineage Diversity, Antibiotic Resistance, and Virulence Determinants Among Methicillin-Resistant and Methicillin-Susceptible Staphylococcus aureus Isolated from Nurses at a Teaching Hospital in Ilam, Iran: Successful Nares Decolonization by Mupirocin. J Glob Infect Dis 2018; 10:67-73. [PMID: 29910566 PMCID: PMC5987374 DOI: 10.4103/jgid.jgid_43_17] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Staphylococcus aureus is known to be responsible for nosocomial infections, and the typing method was useful in managing the reservoir of bacteria. The main aim of this study was to determine the prevalence of S. aureus in the nares and hands of nurses working in Imam Khomeini hospital, Ilam, Iran, as well as to determine the clonal relatedness, antimicrobial susceptibility profiles, different virulence, and resistance determinants among these isolates. The evolution of mupirocin activity in the eradication of methicillin-resistant S. aureus (MRSA) and methicillin-susceptible S. aureus (MSSA) colonization in the nares of the healthcare workers in Ilam, Iran, was also determined in this study. MATERIALS AND METHODS In this cross-sectional study, 80 nurses, auxiliary nurses, and service workers from Imam Khomeini Hospital were enrolled. MRSA, antibiotic susceptibility, and virulence determinants were evaluated. Then, the isolates were subjected to pulsed field gel electrophoresis (PFGE) and Staphylococcal cassette chromosome mec typing. RESULTS Our results demonstrated that 23% of isolates were MRSA. PFGE results demonstrated that pulsotypes A (3 out of 30; 10%) and J (3 out of 30; 10%), pulsotypes E (2 out of 30; 6.7%), M (2 out of 30; 6.7%), P(2 out of 30; 6.7%), and V (2 out of 30; 6.7%) were the most predominant pulsotypes, respectively. CONCLUSION We cannot give conclusive suggestions about the correlation between nasal carriage and infections, but we suggest the monitoring of all healthcare workers annually, decontamination of their noses by using mupirocin and other antistaphylococcal agents, and also the washing of their hands at least every 2 h.
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Affiliation(s)
- Ali Hematian
- Clinical Microbiology Research Center, Ilam University of Medical Sciences, Ilam, Iran
| | - Aazam Monjezi
- Clinical Microbiology Research Center, Ilam University of Medical Sciences, Ilam, Iran
| | - Ramin Abiri
- Department of Microbiology, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Parviz Mohajeri
- Department of Microbiology, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Abbas Farahani
- Department of Microbiology, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Setareh Soroush
- Department of Microbiology, School of Medicine and Razi Herbal Medicines Research Center, Lorestan University of Medical Sciences, Lorestan, Iran
| | - Morovat Taherikalani
- Clinical Microbiology Research Center, Ilam University of Medical Sciences, Ilam, Iran
- Department of Microbiology, School of Medicine and Razi Herbal Medicines Research Center, Lorestan University of Medical Sciences, Lorestan, Iran
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Asadollahi P, Farahani NN, Mirzaii M, Khoramrooz SS, van Belkum A, Asadollahi K, Dadashi M, Darban-Sarokhalil D. Distribution of the Most Prevalent Spa Types among Clinical Isolates of Methicillin-Resistant and -Susceptible Staphylococcus aureus around the World: A Review. Front Microbiol 2018; 9:163. [PMID: 29487578 PMCID: PMC5816571 DOI: 10.3389/fmicb.2018.00163] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 01/24/2018] [Indexed: 12/25/2022] Open
Abstract
Background:Staphylococcus aureus, a leading cause of community-acquired and nosocomial infections, remains a major health problem worldwide. Molecular typing methods, such as spa typing, are vital for the control and, when typing can be made more timely, prevention of S. aureus spread around healthcare settings. The current study aims to review the literature to report the most common clinical spa types around the world, which is important for epidemiological surveys and nosocomial infection control policies. Methods: A search via PubMed, Google Scholar, Web of Science, Embase, the Cochrane library, and Scopus was conducted for original articles reporting the most prevalent spa types among S. aureus isolates. The search terms were “Staphylococcus aureus, spa typing.” Results: The most prevalent spa types were t032, t008 and t002 in Europe; t037 and t002 in Asia; t008, t002, and t242 in America; t037, t084, and t064 in Africa; and t020 in Australia. In Europe, all the isolates related to spa type t032 were MRSA. In addition, spa type t037 in Africa and t037and t437 in Australia also consisted exclusively of MRSA isolates. Given the fact that more than 95% of the papers we studied originated in the past decade there was no option to study the dynamics of regional clone emergence. Conclusion: This review documents the presence of the most prevalent spa types in countries, continents and worldwide and shows big local differences in clonal distribution.
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Affiliation(s)
- Parisa Asadollahi
- Department of Microbiology, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Narges Nodeh Farahani
- Department of Microbiology, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Mehdi Mirzaii
- Department of Microbiology, School of Medicine, Shahroud University of Medical Sciences, Shahroud, Iran
| | - Seyed Sajjad Khoramrooz
- Department of Microbiology, Faculty of Medicine, Cellular and Molecular Research Center, Yasuj University of Medical Sciences, Yasuj, Iran
| | - Alex van Belkum
- Data Analytics Unit, bioMérieux 3, La Balme Les Grottes, France
| | - Khairollah Asadollahi
- Department of Social Medicine, Faculty of Medicine, Ilam University of Medical Sciences, Ilam, Iran.,Faculty of Medicine, Biotechnology and Medicinal Plants Researches Center, Ilam University of Medical Sciences, Ilam, Iran
| | - Masoud Dadashi
- Department of Microbiology, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Davood Darban-Sarokhalil
- Department of Microbiology, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran
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Arslan S, Özdemir F. Molecular characterization and detection of enterotoxins, methicillin resistance genes and antimicrobial resistance of Staphylococcus aureus from fish and ground beef. Pol J Vet Sci 2017; 20:85-94. [PMID: 28525337 DOI: 10.1515/pjvs-2017-0012] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
A total of 120 samples including 40 freshwaterfish(Oncorhynchus mykiss), 40 seawater fish (Sparus aurata) and 40 ground beef samples were examined for the presence of Staphylococcus aureus. The isolates were identified using biochemical tests and a PCR for the species-specific fragment (Sa442) and thermonuclease gene (nucA). The presence of staphylococcal enterotoxin genes (sea, seb, sec, sed and see), toxin genes (eta, etb, tsst), methicillin resistance gene (mecA) and some phenotypic virulence factors was also tested. Genotypic characterization of the isolates was analyzed by PCR-RFLP of the coa gene. Overall, 36 (30%) meat samples were contaminated with S. aureus. Of the 36 isolates, 3 (8.3%) were found to be positive for enterotoxin genes. Only 1 isolate (5.9%) from ground beef had the sea gene. In addition, 1 (12.5%) of the freshwater fish and 1 (9.1%) of the seawater fish carried both the sea and sed genes. The presence of seb, sec, see, eta, etb and tsst was not detected among the isolates of S. aureus. The amplified coa gene revealed five different clusters. Seven and six distinct RFLP patterns were obtained with AluI and HaeIII digestion, respectively. All isolates were found to be positive for slime, hemolytic and DNase activity while 41.7% of them were beta-lactamase positive. The presence of methicillin resistance was neither detected by PCR nor the disk diffusion method. A total of 94.4% of the isolates were resistant to at least one antimicrobial while 44.4% of them were resistant to at least two or more antimicrobials.
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Michiels B, Appelen L, Franck B, den Heijer CDJ, Bartholomeeusen S, Coenen S. Staphylococcus aureus, Including Meticillin-Resistant Staphylococcus aureus, among General Practitioners and Their Patients: A Cross-Sectional Study. PLoS One 2015; 10:e0140045. [PMID: 26458264 PMCID: PMC4601797 DOI: 10.1371/journal.pone.0140045] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Accepted: 09/21/2015] [Indexed: 12/04/2022] Open
Abstract
Background The role of general practitioners (GPs) as reservoir and potential source for Staphylococcus aureus (SA) transmission is unknown. Our primary objective was to evaluate the prevalence of SA and community-acquired methicillin resistant SA (CA-MRSA) carrier status (including spa typing) among GPs and their patients in Belgium. The secondary objective was to determine the association between SA/CA-MRSA carriage in patients and their characteristics, SA carriage in GPs, GP and practice characteristics. Methods The Belgian GPs, who swabbed their patients in the APRES study (which assessed the prevalence of SA nasal carriage in nine European countries; November 2010 –June 2011), were asked to swab themselves as well (May-June 2011). GPs and their patients had to complete a questionnaire on factors related to SA carriage and transmission. SA isolation including CA-MRSA and spa typing was performed on the swabs. Results In eighteen practices 34 GPs swabbed patients of which 25 GPs provided personal swabs. The analysis was performed on 3008 patient records. Among GPs SA carriage (28%) was more prevalent than among their patients (19.2%), but CA-MRSA carriage was not present. SA was more prevalent among younger patients and those living with cattle. Spa typing SA and MRSA strains did not suggest correlation within practices or between patients and GPs, but chronic skin conditions of GPs and always handshaking patients by SA positive GPs were associated with more SA among patients, and hand washing after every patient contact with less SA among patients in practices with high antibiotic prescribing rates. Conclusion No MRSA was found among GPs, although their SA carriership was higher compared to their patients’. Spa types did not cluster within practices, possibly due to difference in timing of swabbing. To minimise SA transmission to their patients GPs should consider taking appropriate care of their chronic skin diseases, antibiotic prescribing behaviour, handshaking and hand washing habits.
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Affiliation(s)
- Barbara Michiels
- Department of Primary and Interdisciplinary Care Antwerp—Centre for General Practice, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
- * E-mail:
| | - Lien Appelen
- Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Barbara Franck
- Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Casper D. J. den Heijer
- Department of Medical Microbiology, Maastricht University Medical Centre/CAPHRI, Maastricht, the Netherlands
| | - Stefaan Bartholomeeusen
- Department of Primary and Interdisciplinary Care Antwerp—Centre for General Practice, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Samuel Coenen
- Department of Primary and Interdisciplinary Care Antwerp—Centre for General Practice, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
- Vaccine & Infectious Disease Institute (VAXINFECTIO)—Laboratory of Medical Microbiology, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
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7
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Rovira G, Cooke EF, Mucavele H, Sitoe A, Madrid L, Nhampossa T, Garrine M, Massora S, Cossa A, Mandomando I, Bassat Q. The Challenge of Diagnosing and Treating Staphylococcus aureus Invasive Infections in a Resource-limited Sub-Saharan Africa Setting: A Case Report. J Trop Pediatr 2015; 61:397-402. [PMID: 26187541 DOI: 10.1093/tropej/fmv045] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND Community-acquired methicillin-sensitive Staphylococcus aureus (CA-MSSA) is responsible for the majority of skin and soft-tissue infections. CA-MSSA can also cause life-threatening infections, possibly in relation to particular virulence factors, including Panton-Valentine leukocidin (PVL). METHODS We describe a severe CA-MSSA necrotizing pneumonia complicated with multifocal osteomyelitis, pericardial effusion and endocarditis in a 6-year-old boy admitted to a Mozambican hospital. Staphylococcus aureus isolation and antibiotic susceptibility testing were performed by conventional microbiology. Additionally, microarray assay was used for molecular characterization. RESULTS Blood culture confirmed the presence of S. aureus susceptible to most antimicrobial agents, including methicillin. Molecular characterization confirmed the presence of PVL, together with alpha and beta haemolysin genes. CONCLUSIONS To our knowledge, this is the first reported case of disseminated CA-MSSA disease with confirmed PVL exotoxin in sub-Saharan Africa. PVL-positive CA-MSSA should be considered in the differential diagnosis of community-acquired pneumonia, making laboratory testing a higher priority.
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Affiliation(s)
- Gemma Rovira
- EAP Sardenya-Hospital de la Santa Creu i Sant Pau, Barcelona, 08025, Spain
| | - Elisa F Cooke
- Unidad de Enfermedades Infecciosas, Servicio de Pediatría, Hospital 12 de Octubre, Madrid, 28041, Spain
| | - Helio Mucavele
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique, CP1929
| | - Antonio Sitoe
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique, CP1929
| | - Lola Madrid
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique, CP1929 ISGlobal, Barcelona Centre for International Health Research (CRESIB), Hospital Clínic - Universitat de Barcelona, Barcelona, 08036, Spain
| | - Tacilta Nhampossa
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique, CP1929 Instituto Nacional de Saúde, Ministério de Saúde, Maputo, Mozambique, CP264
| | - Marcelino Garrine
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique, CP1929
| | - Sergio Massora
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique, CP1929
| | - Anelsio Cossa
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique, CP1929
| | - Inacio Mandomando
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique, CP1929 Instituto Nacional de Saúde, Ministério de Saúde, Maputo, Mozambique, CP264
| | - Quique Bassat
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique, CP1929 ISGlobal, Barcelona Centre for International Health Research (CRESIB), Hospital Clínic - Universitat de Barcelona, Barcelona, 08036, Spain
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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 2013. [PMID: 23183202 DOI: 10.7883/yoken.65.502] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
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 57% of MRSA and 43% of MSSA strains harbored enterotoxin genes. The majority (87.5%) 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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Affiliation(s)
- King Ting Lim
- Microbiology Division, Institute of Biological Science, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia
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Comparative Virulotyping of Salmonella typhi and Salmonella enteritidis. Indian J Microbiol 2013; 53:410-7. [PMID: 24426144 DOI: 10.1007/s12088-013-0407-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Accepted: 04/12/2013] [Indexed: 10/26/2022] Open
Abstract
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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Loop-mediated isothermal amplification assay for the rapid detection of Staphylococcus aureus. BIOMED RESEARCH INTERNATIONAL 2013; 2013:895816. [PMID: 23509796 PMCID: PMC3581241 DOI: 10.1155/2013/895816] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 10/14/2012] [Revised: 01/02/2013] [Accepted: 01/05/2013] [Indexed: 11/17/2022]
Abstract
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 10(2) CFU/mL when compared to 12.5 ng/μL and 10(3) 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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