Identification of and antimicrobial resistance in bacteria causing caprine mastitis in three states and a city in Central Mexico under manual and mechanical milking conditions

Abstract

Mastitis can be caused by infectious agents, bacterial mastitis is the most common, in Mexico, and data regarding mastitis in goats are scarce. The aim of this work was to identify the bacteria most frequently present in goats with mastitis and assess isolate susceptibility to chemotherapeutic agents. A total of 460 samples of goat milk were obtained from the states of Guanajuato, Querétaro, and Morelos and Mexico City. A total of 56 bacteriapositive samples were obtained. Of these bacteria-positive samples, 33 were identified as belonging to the Staphylococcus genus, representing 58.92% of the positive samples. Of the 33 Staphylococcus-positive samples, 16 were identified as S. epidermidis, representing 48.48% of the Staphylococcus-positive samples; 5 each were identified as S. simulans and S. xylosus, each representing 15.15% of the Staphylococcus-positive samples; 3 were identified as S. lentus, representing 9.09% of the Staphylococcus-positive samples; 2 were identified as S. aureus, representing 6.06% of the Staphylococcus-positive samples; and 1 each was identified as S. caprae and S. cohnii, each representing 3.03% of the Staphylococcus-positive samples. Resistance to streptomycin, ampicillin, polymyxin B, tetracycline and tobramycin was assessed using an antibiogram on all specimens that were Staphylococcus-positive. The differences observed in the efficacies of the evaluated drugs illustrate the importance of carrying out tests for the identification of and evaluation of antimicrobial susceptibility in bacterial agents related to mastitis

Virulence Factors in Staphylococcus Associated with Small Ruminant Mastitis: Biofilm Production and Antimicrobial Resistance Genes

“…Coagulase negative staphylococci (CNS), although not as virulent as S. aureus, often cause subclinical mastitis in small ruminants [5,[11][12][13]. This type of infection, most times not detected by the farmer, clearly reduces milk production, also changing milk composition, indirectly impairing the milk product's properties [14].…”

A Brief Update on the Challenges and Prospects for Goat Production in Mexico

“…In western Mexico, bacteriological identification revealed the presence of S. aureus , S. agalactiae , Corynebacterium spp., and coliform bacteria [ 24 ]. In central Mexico, there have been efforts to characterize mastitis-related pathogens; the bacterial genera most frequently isolated in goat milk were coagulase-negative Staphylococcus , mainly S. epidermidis [ 25 ].…”

Polish Journal of Veterinary Sciences

“…To confirm that samples were free of any bacterial agent before the experimental infection, 30 µl of sample was seeded on blood agar and MacConkey agar plates and both plates were incubated at 37°C for 24 hours under aerobic conditions. In the case where no growth was observed, the plates were incubated for 48 further hours until bacterial growth was ruled out (Manzanero et al 2018). A total of 38 milk samples were taken from each goat from the day of birth with weekly sampling (nine samples in total) until reaching the lactation peak (approximately 56 days postpartum).…”

“…Mastitis is one of the most serious diseases for the dairy industry; in dairy goats, the incidence of clinical mastitis may not exceed 5%, while subclinical mastitis is common and about 6 times more than clinical affection (Wanecka et al 2019). The main bacterial genera that cause clinical mastitis are Staphylococcus aureus, Streptococcus agalactiae, S. uberis, S. dysgalactiae and coliforms (Thompson et al 2014, Dore et al 2016, Pirzada et al 2016, Manzanero et al 2018, Novac et al 2019, Kim et al 2019.…”