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Direct Research Journals
Vol.1 (1), pp. 1-8, October 2016
International Standard Journal Number ISJN: A4372-2601

Morphological and Biochemical Characterization of Staphylococci Isolated from Food-Producing Animals in Northern Nigeria
Article Number: DRJA32149043
DOI:

Original Research Article


Mamza, S. A.1*, Geidam, Y. A.1, Mshelia, G. D.2, Egwu, G. O.3 and Gulani I.1


1University of Maiduguri, Department of Veterinary Medicine, P.O. Box, 1069, Maiduguri,Nigeria.

2University of Maiduguri, Department of Veterinary Theriogenology, P.O. Box, 1069, Maiduguri,Nigeria.

3University of Abuja, Department of Veterinary Medicine and Surgery, Abuja, Nigeria.

*Corresponding author E-mail:  sunakimamza@yahoo.com.


date Received: August 1, 2016     date Accepted: September 27, 2016     date Published: October 23, 2016

Abstract

Staphylococcus aureus (S. aureus) is an important pathogen of clinical significance, gram positive coccus, with colonies measuring 1mm in diameter.   Some strains, especially the oxacillin-resistant strains pose a global threat to both humans and animals. Food-animals could be a vehicle for the transmission and spread of the bacteria in humans. In Nigeria, routine enumeration of staphylococci in animals by veterinary microbiological laboratories has less been reported. This study was therefore a bid to observe the morphological, cultural and biochemical characteristics, as well as, oxacillin-resistance ability of staphylococci isolated from food-producing animals including cattle, sheep, goats and chickens, in north-eastern Nigeria, sub-Saharan Africa. A total of 1080 specimens collected from these animals were analyzed for the presence of staphylococci, by culture and biochemical tests. Isolates which formed yellow colonies on mannitol salt agar plates and coagulase-positive, were presumptively suspected to be S. aureus and were screened for oxacillin resistance on oxacillin-resistance screening agar (ORSA). Results revealed that isolates formed round, white-gray or yellow colonies on Columbia blood agar plates (Figure 1, plate A) and 84% of the isolates produced smooth, raised, glistening, yellow or golden yellow colonies on mannitol salt agar plates (Figure 1, plate B). On conventional biochemical tests, 100% were catalase positive, 28.7% were found coagulase positive, 89.5% produced acetoin and 91% possessed carbohydrates hydrolyzing activity.  Prevalence amongst the species indicated cattle (90.5%), sheep (77.1%), goats (89.2%) and chickens (80%). Some isolates (10.9%) formed colonies with intense blue colouration on ORSA medium (Figure 1, plate C), indicative of oxacillin (meticillin) resistance; prevalence being high in cattle (15.8%), sheep (11%) and chickens (10%) than in goats (6%). The presence of oxacillin-resistant staphylococci at this percentage level in food-animals may portend danger to humans, and calls for caution in the livestock industry. The need for regular surveillance and screening for oxacillin-resistant staphylococci in animals is imperative, with a view to recommend appropriate therapy.


Key words:  Staphylococcus, morphology, biochemical, characteristics, oxacillin-resistance, food-animals, Nigeria.