Detection of FUS-1 (OXA-85), a Class D Betalactamase from Fusobacterium nucleatum Subspecies Polymorphum in Nigeria.

Aims: Beta-lactamase production and subsequent resistance to β-lactam drugs has been a global concern in the treatment of Gram negative anaerobes. The aim of this study was to identify F. nucleatum strains producing Class D β-lactamase through the detection of FUS-1 (OXA-85) resistance gene. Place and Duration of Study: Department of Preventive Dentistry, Lagos University Teaching Hospital, Idi-Araba, between February 2010 and November 2010. Methodology: Twenty two oral clinical samples were obtained from patients with chronic periodontitis who admitted to previous use of amoxicillin. Antibacterial susceptibility of the bacterial isolates was determined by E-test on Brucella Blood agar. Amplification of the bacterial DNA was carried out by PCR using F. nucleatum species-specific primer, FUS-1 specific for blaFUS-1 and strain-specific primers for subspecies nucleatum,, fusiforme, polymorphum and vincentii. Results: From the 19 samples collected, F. nucleatum was isolated, and the identity of the isolates was confirmed by PCR. Four of the isolates produced similar bands with the control strain, 3 (15.7%) strains were able to produce amplication with FUS-1 primer specific for blaFUS-1 gene found in β-lactamase producing F. nucleatum subsp. polymorphum. Conclusion: This study shows the presence of class D β-lactamase producing F. nucleatum species in Nigeria.

Associated risk factors and pulsed field gel electrophoresis of nasal isolates of Staphylococcus aureus from medical students in a tertiary hospital in Lagos, Nigeria

Staphylococcus aureus infections are growing problems worldwide with important implications in hospitals. The organism is normally present in the nasal vestibule of about 35 percent of apparently healthy individuals and its carriage varies between different ethnic and age groups. Staphylococcal nasal carriage among health workers is particularly important to establish new clones and track origin of infections during outbreak situations. To determine the carriage rate and compare the pulsed field gel patterns of the strains, nasal swabs were collected from 185 medical students in a teaching hospital in Lagos, Nigeria. Isolates of S. aureus were tested for heamolysin production, methicillin sensitivity and Pulsed Field Gel Electrophoresis (PFGE) was performed. The results showed S.aureus nasal carrier rate of 14 percent with significant rate among males compared to females. All the isolates produced heamolysin. Antibiotic susceptibility pattern revealed that majority of the isolates was susceptible. Five strains (19 percent) harboured resistant determinants to penicillin and tetracycline. None of the strains was resistant to methicillin. 44 percent of the isolates typed by PFGE had type B, the most predominant pulsotype. PFGE A clone exhibited a single resistance phenotype suggesting a strong clonal relationship that could punctual an outbreak in the hospital. The results speculate that nasal carriage among medical personnel could be a function of various risk factors. Personal hygiene and behaviour may however be the means to reducing colonization and spread of S.aureus in our hospitals.