Phenotypic and Genotypic analysis of Staphylococcus spp. from raw bovine milk in Northeastern Brazil

Dairy production is common in Northeastern Brazil. Milk and milk products could be very important sources of foodborne pathogens. In addition, antimicrobials used to treat udder infections may result in the selection of resistant foodborne pathogens. In the study regions, antibiotic usage is kept to a minimum as compared to dairy farms in developed countries. Also, various factors including management and nutrition are distinctly different.

The purpose of this study includes the following:

Study the prevalence of Staphylococcus spp. in raw bovine milk from study region
Investigate antimicrobial resistance profiles of the isolates
Study the prevalence of methicillin- resistant Staphylococcus species
Conduct molecular characterization using SCCmec-typing and mecA amplification

Raw milk samples were collected from 15 different farms in the State of Paraíba of Northeastern Brazil. The farms are representative of the entire State. A total of 552 raw milk samples were collected from 138 apparently healthy cows.

Staphylococcus isolation was done using conventional methods. Agar diffusion method was used to phenotypically characterize all the isolates for 11 antimicrobial agents. Multiplex PCR was used to genotypically characterize the isolates by SCCmec-type (I-IV) and mecA gene amplification.

Staphylococcus isolates were common in milk. This could impose significant food safety hazard to consumers. Methicillin resistance is present in whole milk. Northeastern Brazil is the poorest region of Brazil and no studies have been conducted in antimicrobial resistance in any type of pathogens from this region.