Molecular Characterization of Nosocomial Methicillin Resistant Staphylococcus aureus in Parts of Kaduna State, Nigeria
Molecular Characterization of Nosocomial Methicillin Resistant Staphylococcus aureus in Parts of Kaduna State, Nigeria
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Date
2011-08
Authors
Ahmodu, Opaluwa Saraja
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Abstract
Molecular Characterization of Nosoconial methicillin resistant
Staphylococcus aureus in three geographical areas of Kaduna state was
undertaken. Standard procedure for identification, confirmation, and detection of
mec A gene in staphylococci were followed. A total of 880 samples were
examined from the geographical areas, between January 2008 to June 2010. An
overall prevalence of 8.3% (n=73) was recorded for Staphylococcus infection.
Methicillin resistant Staphylococcus aureus (MRSA) accounted for 56% (n=41) of
all Nosocomial Staphylococcus aureus isolates. 95% (n=70) of isolates were
recorded from wound, urinogenitals and blood and 5% (n=3) isolates came from
other sites (Sputum, and skin). Genarally age groups of peak infection were 1-10
and 41-50. Most of the MRSA isolates came from male, female and surgical
wards, but recovery rate of MRSA was more in accident and emergency and
Special Care Baby Unit (SCBU). Coagulase negative Staphylococcus (CoNs)
accounted for 40% while coagulase positive Staphylococcus accounted for 60% of
MRSA isolates. There was a strong association between resistance to antibiotics
and degree of coagulase produced (P < 0.05). The number of isolates susceptible
decreased when the break point interpretative criteria for establishing resistance
was employed. Cefoxitin had sensitivity of 100% and specificity of 58%. 9.8%
(n=5) of isolates from Zaria resisted all drugs (superbug) while 53% (n=27) were
x
sensitive to all drugs tested. In Kafanchan, 8.3% (n=1) resisted all drugs tested.
15.7% (n=8), 25% (n=3) and 0% (n=0) of isolates, are of erythromycin-inducible,
clindamycin resistant strains in Zaria, Kafanchan and Birnin Gwari respectively.
Overall 16.4% (n=12) resisted Microlide lincosamin streptogramin –B (MLS) and
so are likely to possess erythromycin ribosomal methylase ‘erm’ gene. Antibiotic
profile results of isolates showed that 31.8% (n=7) were resistant to one antibiotic
only. 13.6% (n=3) resisted two antibiotics and 54.5% (n=12) resisted three or more
antibiotics. Quinolone and vancomycin resistant MRSA were detected in hospitals
studied. 66.7% (n=34), 75% (n=9) and 90% (n=9) produced β-lactamase enzyme in
Zaria, Kafanchan and Birnin-gwari respectively. 25% (n=13), 25% (n=3)
expressed PBP2 in Zaria and Kafanchan respectively. Capsular polysaccharide
5&8 were found in 86% (n=44), 83% (n=10) and 70% (n=7) of isolates from Zaria,
Kafanchan and Birnin-gwari respectively. Overall, Mec A gene was detected in
28.1% (n=9), comprising 18.8% (n=6) in Zaria and 9.3% (n=3) in Kafanchan. Mec
A gene was not detected among isolates from Birnin-gwari and so were its
product-PBP2. This result established the existence of Methicillin Resistant
Staphylococcus aureus (MRSA) in all the hospitals studied and that mec A gene
were detected in two of the three Hospitals studied.
Description
A dissertation submitted to the Postgraduate School,
Ahmadu Bello University, Zaria
In Partial Fulfillment, of the requirement for the award of the degree of Doctor of
Philosophy in Microbiology.
Department of Microbiology,
Faculty of Sciences
Ahmadu Bello University,
Zaria – Nigeria
Keywords
Molecular Characterization,, Nosocomial Methicillin,, Resistant Staphylococcus aureus,, Kaduna State,, Nigeria