title: Characterization of methicillin-susceptible and -resistant staphylococci in the clinical setting: a multicentre study in Nigeria.
abstract: BACKGROUND
  The staphylococci are implicated in a variety of human infections; however, many clinical microbiology laboratories in Nigeria do not identify staphylococci (in particular coagulase negative staphylococci - CNS) to the species level. Moreover, data from multi-centre assessment on antibiotic resistance and epidemiology of the staphylococci are not available in Nigeria. This study investigated 91 non-duplicate staphylococcal isolates obtained from the microbiology laboratories of eight hospitals in Nigeria during the period January to April 2010.
  
  
  METHODS
  Identification and antibiotic susceptibility testing was performed using the VITEK 2 system, detection of resistance genes by PCR, and molecular characterization was determined by SCCmec typing, spa and multilocus sequence typing (MLST).
  
  
  RESULTS
  All the isolates were susceptible to mupirocin, tigecycline, vancomycin and linezolid, but 72.5% of CNS and 82.3% of Staphylococcus aureus were resistant to cotrimoxazole, while multiresistance was observed in 37 of the 40 CNS isolates. Untypeable SCCmec types (ccrC/Class A mec and ccr-negative/Class C2 mec gene complex) in two methicillin-resistant S. aureus (MRSA) were identified. Additionally, ccr-negative/Class A mec and ccr type 4/Class C2 mec gene complex was detected in one isolate each of S. sciuri and S. haemolyticus, respectively. The S. aureus isolates were classified into 21 spa types including two new types (t8987, t9008) among the methicillin-susceptible S. aureus (MSSA) isolates. Two (CC8-SCCmecnon-typeable and CC88-SCCmec IV) and four (CC8-SCCmec III/IV/V; CC30-SCCmec II/III; CC88-SCCmec IV; and ST152-SCCmecnon-typeable) MRSA clones were identified in Maiduguri (North-East Nigeria) and South-West Nigeria, respectively. The proportion of Panton-Valentine leukocidin (PVL)-positive MSSA was high (44.4%) and 56.3% of these strains were associated with sequence type (ST) 152.
  
  
  CONCLUSIONS
  The identification of multiresistant mecA positive S. haemolyticus and S. sciuri from clinical samples indicates that characterization of CNS is important in providing information on their diversity and importance in Nigeria. There is the need to develop new SCCmec classification methods for non-typeable methicillin-resistant staphylococci, and to curtail the spread and establishment of the S. aureus ST152 clone in Nigeria. The study presents the first report of a PVL-positive ST152-SCCmecnontypeable MRSA and SCCmec typing of methicillin-resistant CNS in Nigeria.
authors.affiliation: Department of Microbiology, Obafemi Awolowo University, Ile-Ife, Nigeria. bayo_shittu@yahoo.com
authors.forename: Adebayo
authors.initials: A
authors.lastname: Shittu
authors.forename: Omotayo
authors.initials: O
authors.lastname: Oyedara
authors.forename: Fadekemi
authors.initials: F
authors.lastname: Abegunrin
authors.forename: Kenneth
authors.initials: K
authors.lastname: Okon
authors.forename: Adeola
authors.initials: A
authors.lastname: Raji
authors.forename: Samuel
authors.initials: S
authors.lastname: Taiwo
authors.forename: Folasade
authors.initials: F
authors.lastname: Ogunsola
authors.forename: Kenneth
authors.initials: K
authors.lastname: Onyedibe
authors.forename: Gay
authors.initials: G
authors.lastname: Elisha
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D015373:Bacterial Typing Techniques; D006761:Hospitals; D006801:Humans; D016106:Methicillin Resistance; D008826:Microbial Sensitivity Tests; D017720:Molecular Epidemiology; D058889:Molecular Typing; D009549:Nigeria / Q000453:epidemiology; D013203:Staphylococcal Infections / Q000453:epidemiology* / Q000382:microbiology*; D013210:Staphylococcus / Q000145:classification* / Q000187:drug effects* / Q000302:isolation & purification
chemical_list: D000900:Anti-Bacterial Agents