International Journal of Public Health and Epidemiology ISSN: 2326-7291 Vol. 3 (8), pp. 054-058, August,
2014. Available online at www.internationalscholarsjournals.org © International Scholars Journals
Full Length Research Paper
Occurrence of vancomycin-resistant staphylococcus
aureus (VRSA) in fresh and fermented milk in Nigeria: A
preliminary report
Gali Abaka Umaru
1*
, Junaidu Kabir
2
, Veronica J. Umoh
3
, Mohammed Bello
2
, and Jacob K. P.
Kwaga
2
1*
Department of Animal Health, College of Agriculture, P.M.B.1025, Jalingo-660001, Taraba State, Nigeria.
2
Faculty of Veterinary Medicine, Department of Veterinary Public Health and Preventive Medicine, Ahmadu Bello
University, Zaria, Nigeria.
3
Faculty of Science, Department of Microbiology, Ahmadu Bello University, Zaria, Nigeria.
Accepted 7, April 2014
A study was conducted to determine the occurrence of vancomycin resistant S. aureus (VRSA) in milk in
Nigeria. Fourty seven S. aureus were isolated from the 372 milk samples examined, out of which 20 (5.4%)
were vancomycin-resistant. Fifteen (4%) of the VRSA were isolated from raw milk, 4 (1.1%) from bulk milk
and 1 (0.3%) from pasteurized milk. No significant difference (P > 0.05) between the occurrence among the
study variables was observed, . No VRSA occurred in the yogurt and ‘kindirmo’ samples examined. The
decrease in the occurrence of the pathogen from raw milk to pasteurized milk and its absence in yogurt
and ‘kidirmo’ suggest that pasteurization and fermentation may have eliminated most of the organisms. The
resistance profiles of the VRSA isolates to other antibiotics showed high resistance to penicillin (100%),
tetracycline (85%), amoxicillin (65%), methicillin (40%) and oxacillin (40%), but low to amikacin (5%) and
sulphamethoxazole/trimethoprim (10%). None of the isolates were resistant to chloramphenicol and
ciprofloxacin. The multiple antibiotic resistance index result revealed that 80% of the VRSA were resistant
to 3 or more antibiotics. The presence of VRSA coupled with the multple resistance patterns of these
isolates are of great concern and also of public health significance. Therefore more studies on the
epidemiology of this pathogen in foods are required.
Key words: Vancomycin-resistant Staphylococcus aureus (VRSA), Fresh Milk, Fermented Milk, Multiple Antibioic
Resistance Index (MARI), Preliminary report, Nigeria.
INTRODUCTION
In an attempt to isolate methicillin-resistant S. aureus
(MRSA) in fresh and fermented milk in Zaria and Kaduna,
Nigeria, significant percentage of the isolated S. aureus
were discovered to be vancomycin resistant following
antibiotic resistance testing. This is of great concern
since vancomycin is the drug of choice after the failure of
methicillin, coupled with the fact that vancomycin
resistance is rarely reported even in clinical cases. This
report, therefore serves as preliminary information on the
occurrence of vancomycin resistant Staphylococcus
aureus (VRSA) in fresh and fermented milk in Zaria and
*Corresponding author.E-mail: drghaliumaru@yahoo.com.
Kaduna, Nigeria. Staphylococcus aureus (S. aureus) is
one of the bacteria that have developed resistance to
most classes of antibiotics including methicillin (Weigel et
al., 2007). Vancomycin then became a drug of choice for
the treatment of infections with S. aureus and methicillin-
resistant Staphylococcus aureus (MRSA), until in 1996
when the first Vancomycin-resistant Staphylococcus
aureus (VRSA) was isolated from a Japanese patient
(Hiramatsu, 2001). Subsequently, it was isolated in USA,
France, Korea, South Africa, and Brazil (Hiramatsu,
2001; Weigel et al., 2007). Vancomycin-resistant
Staphylococcus aureus (VRSA) is therefore, a strain of
Staphylococcus aureus that is resistant to the antibiotic
glycopeptide, vancomycin (Chang et al., 2001). The
resistance is acquired by mutation and thickening of cell