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The molecular characterization of non- typeable methicillin resistant Staphylococcus aureus (MRSA) clones

Research Scholar

Benear Apollo Obanda, Veterinary Preventive Medicine (Kenya)
Shu-Hua Wang, Co-Researcher
Lilly Bebora, Co-Researcher
Wondwossen Gebreyes, Faculty Mentor


Benear Apollo Obanda is a research officer and scientist at the Kenya Medical Research Institute, Centre for Microbiology Research, Nairobi, Kenya. He is a PhD candidate at the Faculty of Veterinary Medicine in the Department of Veterinary Pathology, Microbiology and Parasitology at the University of Nairobi, Kenya. Obanda is currently a visiting research scholar-PhD Fellow through the National Institutes of Health Fogarty International Center's “Molecular Epidemiology and Key Issues of Food borne Pathogens in Eastern Africa" grant.

What is the issue or problem addressed in your research?

Staphylococcus aureus is a versatile human pathogen and animals causing infections ranging from relatively mild involvement of skin and soft tissue to life- threatening sepsis, pneumonia, and toxic shock syndrome (TSS). The organism causes illness through production of numerous cell surfaces and secreted virulence factors, and disease is facilitated by its propensity to develop resistance to multiple antibiotics. Staphylococcal cassette chromosome mec (SCCmec) typing is essential for understanding the molecular epidemiology of methicillin-resistant Staphylococcus aureus (MRSA). SCCmec elements are currently classified into types I to XI based mec and ccr gene complexes, and are further classified into subtypes. Previously published multiplex PCR assay is limited in its ability to detect recently discovered types and subtypes.

What methodology did you use in your research?

Non typable Staphylococcus ssp isolates have been characterized using antibiogram, pulsed-field gel electrophoresis and multilocus sequence typing, Staphylococcus protein A (spa) typing, and staphylococcal cassette chromosome mec (SCCmec) typing. Fifteen isolates have been identified by multiplex PCR assay to contain portions of Staphylococcal cassette chromosome mec (SCCmec) with varying mec and ccr gene complexes sequence. This portion will be DNA sequenced and compared with known mec and ccr gene complexes with a view to identify difference between them. The difference between these two group may lead to identification of a new novel Staphylococcal cassette chromosome mec (SCCmec). Panton-Valentine Leukocidin (PVL), capsular polysaccharides types (cap) 5 and 8, accessory genes regulators (agr), Staphylococcal enterotoxins (SE) and toxic shock syndrome toxin 1 (tst) associated genes will be identified.

What are the purpose/rationale and implications of your research?

MRSA strains are a major cause of infections in the community and hospital settings. This changing epidemiology of MRSA poses a challenge to public health and infection control in hospital settings.