Ticari buzağı mamalarının mikrobiyolojik analizi ve izole edilen Enterococcus türlerinde antibiyotik dirençliliği

Abstract

One of the reasons why calf milk replacer is preferred over unpasteurized bulk tank milk or waste milk with antibiotics on farms is that it prevents epidemic diseases and antibiotic resistance that may occur on the farm. In this study analyzed commercial calf milk replacer products (n = 12) obtained from dairy farms around Turkiye by microbiological culture and polymerase chain reaction (PCR). In order to evaluate the microbiological quality of calf milk replacer, total bacteria count, coliform E. coli and E. coli O157-H7, Salmonella spp., Staphylococcus spp., Streptococcus spp., Enterococcus spp. analyses were performed according to microbiological analysis methods determined according to ISO standards. Enterococcus spp. was isolated from all 12 calf milk replacer samples analyzed and molecularly confirmed by PCR with the presence of the gross-Es gene. Salmonella spp., E. coli, Staphylococcus spp. and Streptococcus spp. were not isolated from the samples. Additionally, in the bacterial counts, an average of 5.3x107 Enterococci were counted from all samples in 1 gram of calf milk replacer. Antimicrobial analysis of the isolated bacteria was completed according to CLSI 2022 data, and 11 isolates were defined as multi drug resistance and one isolate was defined as extensive drug resistance. It was also determined that the isolate defined as extensive drug resistance was resistant to Vancomycin and carried the Van A resistance gene. Many proteins used in the preparation of calf milk replacers are of animal origin and may contain pathogenic bacteria. Milk replacers are used on most farms for biosecurity purposes. It is known that milk replacers affect microbiota. It was shown in this study that if calf milk replacers are not prepared under the regulations, they may cause harm rather than benefit to on-farm biosecurity factors. It is concerning that calves are given calf milk replacers containing antibiotic-resistant Enterococcus spp. to sustain their lives when they are most vulnerable to disease during the window of susceptibility. When using calf milk replacer in calf feeding, field veterinarians should be informed about the microbiological certification of the product and provide information about pasteurization and presentation for consumption.