Antibiotic resistance and molecular epidemiology of Staphylococcus aureus in Nigeria
Creators: name: Shittu, Adebayo
name: Okon, Kenneth
name: Adesida, Solayide
name: Oyedara, Omotayo
name: Witte, Wolfgang
name: Strommenger, Birgit
name: Layer, Franziska
name: Nübel, Ulrich
Publisher: name: Robert Koch-Institut, Infektionskrankheiten / Erreger
Year: 2011
Subjects: subject: Adolescent
subject: Humans
subject: Female
subject: Polymerase Chain Reaction
subject: Cluster Analysis
subject: Male
subject: Middle Aged
subject: Nigeria/epidemiology
subject: Child
subject: Adult
subject: Aged
subject: Infant
subject: Leukocidins/genetics
subject: Staphylococcus aureus/drug effects
subject: Staphylococcus aureus/genetics
subject: Staphylococcus aureus/isolation &amp; purification
subject: Young Adult
subject: Anti-Bacterial Agents/pharmacology
subject: Molecular Epidemiology
subject: Child Preschool
subject: Bacterial Toxins/genetics
subject: Staphylococcal Infections/epidemiology
subject: Staphylococcal Infections/microbiology
subject: Exotoxins/genetics
subject: Infant Newborn
subject: Staphylococcus aureus/classification
subject: Virulence Factors/genetics
subject: Drug Resistance Bacterial
subject: Molecular Typing
subject: Phylogeography
subject: 610 Medizin

description: Background: Staphylococcus aureus is an important pathogen causing a wide range of infections in the hospital and community setting. In order to have adequate information for treatment of S. aureus infections, it is crucial to understand the trends in the antibiotic-resistance patterns. In addition, the occurrence and changes in types of S. aureus, clonal identities, and their geographic spread is essential for the establishment of adequate infection control programmes. In this study, 68 S. aureus isolates obtained from clinical and non-clinical sources in Nigeria between January and April 2009 were characterized using phenotypic and molecular methods. Results: All the S. aureus isolates were susceptible to teicoplanin, vancomycin, phosphomycin, fusidic acid, rifampicin, daptomycin, mupirocin, linezolid and tigecycline. Sixteen percent of the isolates were resistant to oxacillin, while 55% and 72% of isolates were resistant to tetracycline and trimethoprim/sulphamethoxazole (cotrimoxazole), respectively (Table 1). There was excellent correlation between the broth microdilution assay and detection of antibiotic resistance genes by the multiplex PCR, in the determination of S. aureus resistance to erythromycin, gentamicin, methicillin and tetracycline. A total of 28 spa types were identified in the study, and the predominant spa type among the methicillin-susceptible S. aureus (MSSA) isolates was t084 (13 isolates). The t037- ST241-SCCmecIII type was the only clone identified in Maiduguri (North-East Nigeria) while in South-West Nigeria, diversity among the MRSA isolates (t451-ST8-SCCmecV; t008-ST94-SCCmecIV; t002-ST5-SCCmecV; t064-ST8-SCCmecV) was observed. The toxin genes seh and etd were detected in isolates affiliated with clonal complexes CC1, CC80 and sequence type ST25, respectively. The proportion of PVL-positive isolates among MSSA was high (40%). Most of the PVL-positive MSSA isolates were obtained from wound infections and associated with clonal complexes CC1, CC30, CC121 and with sequence type ST152. Conclusions: The use of phenotypic and molecular methods provided useful information on antibiotic resistance and molecular diversity of S. aureus in Nigeria. The high proportion of PVL-positive MSSA isolates affiliated to various clonal complexes and detected in all the health institutions is a major concern, both as a source of severe infections and as a potential reservoir that could lead to the emergence of PVL-positive MRSA. This study presents the first baseline information on the nature of the antibiotic resistance genes from S. aureus isolates in Nigeria. There is the need to curtail the spread and establishment of MRSA and PVL-positive MSSA clones in Nigerian health care institutions.