Isolation of bovine clinical mastitis bacterial pathogens and their antimicrobial susceptibility in the Zenica region in 2017

Ova studija predstavlja podatke prikupljene iz Veterinarske stanice “Zevet” d.o.o. Zenica, Bosna i Hercegovina o zastupljenosti bakterijskih patogena kod klinički prisutnih mastitisa mliječnih goveda i profilima njihove antimikrobne osjetljivosti. Za laboratorijsku izolaciju obrađena su 52 uzorka od kojih su 23 bila bakteriološki pozitivna. Najčešći izolati bili su Staphylococcus aureus u 21,74 % uzoraka i Streptococcus agalactiae u 17,39 % izolira- nih uzoraka, koagulaza-negativni stafilokoki (13,04 %), Klebsiella pneumoniae (13,04 %), Ente- rococcus spp. (8,70 %), Escherichia coli (8,70 %), Streptococcus spp., Enterobacter, Serratia spp. i Yersinia enterocolitica (4,35 %). Najveća antimikrobna otpornost među izolatima primjećena je na benzilpenicilin (56,25 %) i oksitetraciklin (46,15 %) s ukupnom otpornosti na uporabljena antimikrobna sredstava od 25,99 %. Na tri testirana antimikrobna sredstva (neomicin, klindamicin i cefotaksim) izolati nisu pokazali otpornost. Ostali antibiotici na koje je primijećena niska ukupna otpornost su ciprofloksacin (5,56 %) i ofloksacin (6,67 %). Samo jedan izolat nije pokazao nikakvu otpornost na testirane antimikrobike (S. aureus). Najveću otpornost među izolatima pokazao je Enterococcus spp., pokazujući senzibilitet samo za tetracikline. S. aureus je pokazao otpornost na benzilpenicilin i cefaleksin u 60 % slučajeva. Svi izolati S. agalactiae su bili otporni na tetracikline, oksitetracikline i gentamicin. Koagulaza negativni stafilokoki pokazali su otpornost na cefaleksin u dva slučaja i otpornost na benzilpenicilin, eri- tromicin i oksacilin u jednom izolatu. Klebsiella pneumoniae je pokazala otpornost na cefaleksin, amoksicilin i benzilpenicilin u svim ispitivanim izolatima, a pokazala je i otpornost na tetracikline u dva izolata. Svi ostali izolati pokazali su otpornost prema najmanje jednom testiranom antimikrobiku. U 46 slučajeva se odmah pristu- palo liječenju s 86,96 % uspjehom koji je procijenjen na osnovu izostanka kliničkog relapsa i smanjenja broja somatskih stanica u dopuštene granice za tri tjedna nakon provedene terapije.This study provides data on the bacterial pathogens present in clinical mastitis of dairy cattle and their antimicrobial susceptibility profiles, collected by the Zevet Veterinary Station in the Zenica region in Bosnia and Herzegovina. A total of 52 samples were taken for laboratory isolation and 23 bacterial pathogens were isolated. The most common isolates were Staphylococcus aureus in 21.74% of samples and Streptococcus agalactiae (17.39%), followed by coagulase negative staphylococci (13.04%), Klebsiella pneumoniae (13.04%), Enterococcus spp. (8.70%), Escherichia coli (8.70%), Streptococcus spp., Enterobacter, Serratia spp. and Yersinia enterocolitica (4.35%). The highest antimicrobial resistance among isolates was observed with tested benzylpenicillin (56.25%) and oxytetracyline (46.15%) with an overall resistance of used medical agents of 25.99%. Three of the tested antimicrobial agents (neomycin, clindamycin and cefotaxim) did not show resistance. Other antibiotics with low total resistance were ciprofloxacin (5.56%) and ofloxacin (6.67%). Only one isolate showed no resistance to the tested antimicrobials (S. aureus). The highest resistance between the isolates was shown by Enterococcus spp., showing sensitivity only to tetracycline. S. aureus showed resistance to benzylpenicillin and cephalexin in 60% of cases. All S. agalactiae isolates were resistant to tetracycline, oxytetracycline and gentamicin. Coagulase negative staphylococci showed resistance to cephalexin in two cases and resistance to benzylpenicillin, erythromycin and oxacillin in one isolate. Klebsiella pneumoniae showed resistance to cephalexin, amoxicillin and benzylpenicillin in all tested isolates, and showed resistance to tetracyclines in two isolates. All other isolates showed resistance to at least one of the antimicrobials tested. A total of 46 cases were treated immediately after clinical diagnosis with an 86.96% success rate, which was estimated based on the absence of clinical relapse and a decrease in the number of somatic cells within the permissible three week limit after therapy