Prevalence, antimicrobial susceptibility and molecular typing of Methicillin-Resistant Staphylococcus aureus (MRSA) in bulk tank milk from southern Italy.

This paper assesses the prevalence of MRSA in bulk tank milk (BTM) samples from southern Italy, and the relationship between the Coagulase Positive Staphylococci count (CPS) and MRSA prevalence. Of 486 BTM samples tested, 12 samples (2.5%) resulted positive for the presence of MRSA. Great genetic diversity was found among the isolates: ST1/t127 and t174/IVa, ST5/t688/V, ST8/t unknown/IVa/V, ST45/t015/IVa, ST71/t524/V, ST88/t786/Iva, ST398/t011 and t899/IVa/V and ST2781/t1730/V. All isolates were pvl-negative and icaA positive. The majority of strains (58%) carried the ses (sec, seh, seg, seo, sem and sen) genes. All tested strains resulted susceptible to amikacin, cephalotin, cloramphenicol, gentamycin, trimethoprim - sulfamethoxazole, tobramycin and vancomycin, and variably resistant to ampicillin, oxacillin and tetracycline. No statistical association between the CPS count and MRSA detection was found in the MRSA-positive samples. Although some of the spa-types and STs detected in our survey are known to cause human infections, raw milk from Italian herds in the considered area is not a common source of MRSA. Nonetheless, it is necessary to assess the risk of foodborne infection and the risk related to the handling of milk.

Screening of commercial milk samples using ELISA for immuno-epidemiological evidence of infection by the cattle grub (Diptera: Oestridae).

Pasteurised and ultra high temperature (UHT)-treated milk were tested over the period November 1997-February 1998 in order to evaluate the applicability of an hypodermosis ELISA test on commercial milk samples. Milk samples from six dairy companies were analysed and the development of anti-Hypoderma antibodies recorded for the period from September 1998 to June 1999. For one dairy (no. 3) bulk milk samples were also obtained from the tankers, transporting milk away from the farms, and analysed; the results were compared to the parasitological status of the cows whose milk had been collected on the farms. Out of 32 pasteurised samples tested, 23 were positive, exceeding the cut-off (22%), while 9 samples were negative. UHT milk was always negative. The antibody levels in milk samples from four of the six companies were highest during January and decreased gradually during February to May 1999. The bulk milk samples also had high antibody levels and 47.2% of milk producing cows had lesions of hypodermosis. It was concluded that testing commercial milk for antibodies is an efficient way of detecting the presence of hypodermosis in cattle, especially in those countries for which no data on this disease are available.