Isolation of Methicillin – Resistant Staphylococci from Meat and Milk Foodstuff

K. BOJKOVA1 and I. STEFANOV2
1 Medical University, Department of Microbiology, BG-9002 Varna, Bulgaria
2 Regional Veterinary Station, BG-9700 Shoumen, Bulgaria

Abstract

BOJKOVA, K. and I. STEFANOV, 2001. Isolation of methicilin – resistant staphylococci from meat and milk foodstuff. Bulg. J. Agric. Sci., 7: 201-206

Staphylococci are among the most common bacterial pathogens in human and animals all over the world. It is well-established fact that methicillin-resistant staphylococci (MRS) are usually associated with infections in humans. Purpose of study is to determine the frequency of MRS in animal alimentary products, to define mechanisms of their in vitro resistance to Oxacillin and to test MRS for in vitro resistance to Teicoplanin. All 128 staphylococci strains were tested as follows: (i) by diffusion method with disc containing 1 mg Oxacillin; (ii) by agar screen method with 6 mg/l Oxacillin and 4% NaCl and (iii) by an agar dilution method. 40 MRS or 31.3% from total strains were defined. From 24 strains S. aureus 16 were MRSA and from 103 S. epidermidis – 24 strains were MRSE. 9 strains from total 40 MRS were defined as borderline resistant, from them 6 were S. aureus and 3 were S. epidermidis. 31 strains were intrinsic resistant, from them 10 were S. aureus and 21 were S. epidermidis. From 24 MRSE 2 strains were resistant and 7 were intermediate to Teicoplanin. No resistant and intermediate strains were established from 16 MRSA. Isolation of MRS from milk and meat products and the presented results about their resistance to Oxacillin and Teicoplanin lead to the conclusion that use of b-lactam antibiotics in veterinary practice have to be controlled because of the possibility for their transmission from animals to men by foodstuff.

Key words: methicillin-resistant staphylococci, meat and milk foodstuff, and resistance to Oxacillin and Teicoplanin