Phenotype and genotype charactristics of coagulase - positive staphylococci isolated from cows udder

Beograd : [N. S. Rajić Savić]

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Veterinarska medicina- Higijena i tehnologija mleka / Veterinary medicine - Hygiene and Milk Technology

Mastitis je najčešće obolenje mlečnih krava i uzrok je najvećih gubitaka u primarnoj proizvodnji mleka u svetu, a najčešće su izazvani koagulaza pozitivnim stafilokokama. Rezistencija stafilokoka izolovanih u slučajevima mastitisa prema antimikrobnim sredstvima je u porastu i prati rezistenciju stafilokoka izolovanih u slučajevima oboljenja ljudi, pre svega na penicilin i ampicilin, kao i na preparate iz drugih grupa antimikrobnih lekova. Najznačajniji toksini koji stvaraju koagulaza pozitivne stafilokoke su enterotoksini i imaju veliki značaj za zdravlje ljudi, jer izazivaju alimetarne intoksikacije, a mleko i proizvodi od mleka predstavljaju rizične proizvode u kojima se enterotksini mogu naći. Novija istraživanja pokazuju da do 93,6% stafilokoka izolovanih u slučajevima mastitisa ima sposobnost da stvara jedan ili više enterotoksina. Cilj istraživanja je bio da se utvrdi da li postoji razlika u fenotipskim i genotipskim karakteristikama koagulaza pozitivnih stafilokoka izolovanih iz uzoraka mleka uzetih u slučajevima latentne infekcije, subkliničkih mastitisa i kliničkih mastitisa krava u različitim fazama laktacije i da li postoji veza izmeĎu osetljivosti koagulaza pozitivnih stafilokoka na antimikrobne lekove i prisustva gena za stvaranje enterotoksina. Uzorci mleka za bakteriološko ispitivanje na uzročnike mastitisa su uzeti iz pojedinih četvrti vimena od 9.181 krave u različitim fazama laktacije sa tri farme. Kod svih (830) izolata koagulaza pozitivnih stafilokoka koji su izolovani iz uzoraka mleka uzetih u različitim fazama laktacije ispitana je osetljivost disk difuzionom metodom po Kirbi Bauer-u na odabrane antimikrobne lekove. Za ispitivanje rezistencije na meticilin oksi testom sa oksicilinom i cefoksitinom ispitano je 373 izolata za koje je disk difuzionim testom utvrĎeno da su rezistentni na penicilin G. Za ispitivanje biohemijskih osobina i sposobnosti sinteze enterotoksina odabrano je 50 izolata koagulaza pozitivnih stafilokoka izolovanih iz uzoraka mleka krava sa subkliničkim mastitisom od kojih je za 35 (78,6%) izolata disk difuzionom metodom utvrĎeno da su rezistentni na penicilin G i 15 (21,4%) izolata osetljivo na penicilin G. diskovi antimikrobnih lekova sledećih koncetracija: penicilin G 6μg (Torlak), amoksicilin/klavulanska kiselina (20+10 μg ) (Oxoid), kloksacilin 25 μg (Oxoid), amoksicilin 30 μg (Torlak), cefaleksin 30 μg (Torlak), ceftiofur 30 μg (Oxoid), linkomicin 15 μg (Oxoid), gentamicin 30 μg (Torlak), i tetraciklin 30 μg (Torlak)...

Mastitis in dairy cows is the persistent, inflammatory reaction of udder tissue. Mastitis cause the greater losses on primary production in milk in world, and most prevalence pathogens are coagulase-positive staphylococci. Resistance of staphylococci into the isolated in bovine udder a cases of mastitis on antimicrobial agents increasing and monitoring resistance of isolated staphylococci in cases in humans infections, especially of penicillin and ampicillin, as well as the preparation of other groups of antibiotics. The main toxins produced coagulase positive staphylococci are enterotoxins and have great significance of human health, causing alimntary intoxication. Milk and milk products are risk factors for enterotoxins existing. Recent research shows that up to 93,6% of staphylococci isolated in cases of mastitis in the ability in produces one or more enterotoxins. The aim of this study was to determine whether there are differences in phenotypic and genotypic characteristics of coagulase-positive staphylococci isolated from milk samples taken in cases of latent infection, mastitis, subclinical and clinical mastitis at different stages of lactation, and whether there is a link between susceptibility of coagulase-positive staphylococci antimicrobial drugs and the presence of genes for production of enterotoxins. Milk samples for bacteriological examination of the causes of mastitis are taken from individual quarters of the udder from 9,181 cows at different stages of lactation from three farms. In all (830) isolates of coagulase-positive staphylococci, isolated from milk samples taken at different stages of lactation examined the sensitivity of disk diffusion method by Kirby-Bauer in the selected antimicrobials. To test resistance to methicillin oxy test with oxacillin and cefoxitin were examined 373 isolates for which the disk diffusion assay showed that are resistant to penicillin G. For the investigation of biochemical properties and the ability to synthesize enterotoxin of 50 selected isolates of coagulase-positive staphylococci isolated from milk samples of cows with subclinical mastitis of which is 35 (78.6 %) isolates by disk diffusion method showed that are resistant to penicillin G and 15 (21,4 %) isolates susceptible to penicillin G. Drives the following concentrations of antibiotics: penicillin G 6μg (Torlak), amoxicillin/clavulonic acid (20+10mg) (Oxoid), cloxacillin 25 mg (Oxoid), amoxicillin 30 mg (Torlak), cephalexin 30 mg (Torlak), ceftiofur 30 mg (Oxoid), lincomycine 15 mg (Oxoid), gentamicine 30 mg ( Torlak ) and tetracycline 30 mg (Torlak)...

koagulaza pozitivne stafilokoke, infekcija, mastits, prevalenca, pigment, hemoliza, identifikacija, antimikrobna osetljivost, rezistencija na meticilin, enterotoksini

coagulase-positive staphylococci, infections, mastitis, prevalence, pigment, haemolysis, identification, antimicrobial susceptibility, resistance to methicillin, enterotoxins

575.2:599.735.5

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