Classification of dairy properties according to the geometric mean of the somatic cell count and its antimicrobial resistance profile

Abstract

Milk and its derivatives are highly consumed foods worldwide, with recognized nutritional importance. The search for the production of products with superior quality is constant. For the present work, 26 milk-producing properties were selected, with a total of 506 milk samples collected during the period from October 2019 to May 2020 being evaluated. The objective of this study was to evaluate the quality of milk produced in dairy properties in the region west Paraná, classified as good or bad based on the results of the Somatic Cell Count (SCC) and through sampling (n = 10) to evaluate the resistance profile of enterobacteria and Staphylococcus spp. isolated from milk samples, in addition to the presence of the mecA gene in strains of Staphylococcus spp. resistant to oxacillin. There were significant differences between the good and bad properties for the levels of lactose, SCC (cell/mL), and Standard Plate Count (SPC) (CFU/mL). The strains of Staphylococcus spp. showed differences in the percentage of resistance in relation to the good and bad properties for antibiotics: tetracycline, ciprofloxacin, oxacillin, amikacin, clindamycin, gentamycin, and erythromycin. The mecA gene was not detected in any of the coagulase-negative Staphylococcus isolates that showed resistance to oxacillin. For enterobacteria, the isolated species differed in relation to the classification of properties, with predominance for Escherichia coli (40%) for properties classified as bad and Hafnia alvei (40%) for those classified as good. The percentage of antibiotic resistance compared to enterobacteria isolates was higher in properties classified as good. Monitoring through microbial culture and antibiogram is extremely important, favoring the correct choice for the treatment of animals with a reduced selection of resistant strains.