Characterization of Staphylococcus Species Isolated from Raw Milk and Milk Products (lben and jben) in North Morocco

ABSTRACT

Background: To investigate the incidence and antibiotic resistance of staphylococcal strains isolated from milk and milk products and to trace the ecological origin of the Staphylococcus aureus isolated. Methodology: Eighty-one samples of raw milk; lben (whey) and jben (cheese) were analyzed for the presence of staphylococcal strains. Isolates were identified by Gram stains; tests for coagulase; the API staph system and the WalkAwayr 40/96; which also determines the antimicrobial susceptibility profiles. The S. aureus strains were biotyped; and variable regions of the coagulase gene were amplified using the polymerase chain reaction. Results: The identification results showed a predominance of coagulase-negative staphylococci (54). Coagulase-positive staphylococci that were identified were divided into 3 groups comprising S. aureus (40); Staphylococcus intermedius (2) and Staphylococcus hyicus (4). Among the S. aureus that was isolated; biotype C was the predominant biotype. Among 40 coagulase gene PCR-amplification products; 37 produced a single band; while 3 isolates produced two bands. The antimicrobial susceptibility-profile of the staphylococcal strains revealed a high incidence of S. aureus to penicillin G. In addition; Staphylococcus lentus presented considerable resistance to the oxacillin; erythromycin and lincomycin. Conclusions: The presence of staphylococci in raw milk; lben and jben in areas of northern Morocco poses a health hazard; so it is necessary for the public health inspectors to properly examine the conditions during production; storage and commercialization of all products made with unpasteurized milk. Key Words milk products; Staphylococcus; coagulase-gene typing; biotyping; antimicrobial susceptibility