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    Öğe
    Antimicrobial susceptibility, presence of resistance genes and biofilm formation in coagulase negative staphlococci isolated from subclinical sheep mastitis
    (Veteriner Fakultesi Dergisi, 2012) Ergün, Yaşar; Aslantaş, Özkan; Kireçci, Ekrem; Öztürk, Fatma; Ceylan, Ahmet; Boyar, Yilmaz
    In this study, coagulase negative staphylococci (CoNS) (n = 70) isolated from subclinical sheep mastitis were screened for minimum inhibitory concentration (MIC) to antimicrobials used commonly in veterinary field in Turkey. In addition, plasmid profiling and biofilm production of CoNS isolates was investigated. All isolates were found to be susceptible to amoxycillin-clavulanic acid, cephalothin, gentamicin, enrofloxacin and oxacillin. The highest resistance was observed in 42.9% (n = 30) of the isolates against the beta-lactam antibiotics, penicillin and ampicillin. All beta-lactam resistant isolates produced beta-lactamase and carried blaZ. Tetracycline resistance was observed in 11.4% (n = 8) of the isolates, either alone or in combination with beta-lactams and macrolides. Of the tetracycline resistant 8 isolates, 5 carried the tetK gene, one carried the tetM and 2 isolates carried both genes together. Erythromycin resistance was observed in 5.7% of the isolates; msrA was detected alone (one isolate) or in combination with mphC (one isolate) and ermC (one isolate). ermA was observed only in one isolate. Most of the strains showed only a single plasmid band in size of 19.3 kb, but some had 2 to 3 plasmids ranging from >19.3 kb to 0.9 kb. Out of 70 CoNS isolates, 28 (40%) were identified as biofilm producer by Congo red agar (CRA) method, and 30 (42.9%) were positive for both icaA and icaD genes, which are known to be responsible for biofilm formation in CoNS.
  • Küçük Resim
    Öğe
    Antimicrobial susceptibility, presence of resistance genes and biofilm formation in coagulase negative staphlococci ısolated from subclinical sheep mastitis
    (2012) Ergün, Yaşar; Öztürk, Fatma; Aslantaş, Özkan; Ceylan, Ahmet; Kireççi, Ekrem; Boyar, Yılmaz
    Bu çalışmada, subklinik koyun mastitislerinden izole edilen koagulaz negatif stafilokokların (KNS) (n = 70) veteriner hekimlik alanında yaygın olarak kullanılan antimikrobiyallere minimal inhibitor konsantrasyonları (MİK), plazmid profilleri ve biyofilm üretimi araştırıldı. Tüm izolatlar amoksisilin-klavulanik asid, cefalotin, gentamisin, enrofloksasin ve oksasiline duyarlı bulundu. En yüksek direnç izolatların %42.9’unda (n = 30) beta-laktam antibiyotiklere (penisilin ve ampisilin) karşı gözlendi. Beta-laktam antibiyotiklere dirençli izolatların tamamı beta-laktamaz sentezlediği ve blaZ genini taşıdığı belirlendi. Tetrasiklin direnci tek veya beta-laktam antibiyotikler ve makrolidlerle kombine olarak izolatların %11.4’ünde (n = 8) gözlendi. Tetrasiklin dirençli izolatların 5’inde tetK, birinde tetM ve ikisinde de her iki geni birlikte bulundu. Eritromisin direnci izolatların %5.7’sinde (n = 4) bulundu. msrA, mphC, ermA birer izolatta, ermC ise msrA geni ile kombine olarak bir izolatta tespit edildi. İzolatların büyük kısmı 19.3 kb büyüklüğünde tek plasmid gösterirken, bazı izolatlar büyüklüğü >19.3 kb ile 0.9 kb arasında değişen 2-3 plazmid taşıdığı belirlendi. Yetmiş KNS izolatından 28’i (%40) Kongo Red Agar (KRA) metodu ile biyofilm sentezi ve 30’unun da (%42.9) biyofilm sentezinden sorumlu olan icaA ve icaD genleri yönünden pozitif olduğu saptandı.
  • Küçük Resim
    Öğe
    Prevalence and Molecular Mechanism of Macrolide and Lincosamide Resistance in Staphylococci Isolated from Subclinical Bovine Mastitis in Turkey
    (Japan Soc Vet Sci, 2011) Aslantas, Ozkan; Ozturk, Fatma; Ceylan, Ahmet
    Macrolide and lincosamide (ML) resistance and the related resistance genes of staphylococci were assessed from cases of bovine subclinical mastitis. Of the 104 Staphylococcus aureus and 62 coagulase negative staphylococcus (CoNS) isolates, 26 (25%) and 12 (19.4%) were resistant to ML, respectively. While constitutive ML resistance phenotype accounted for 15.4% (16/104) of S. aureus and 8.1% (5/62) of CoNS, inducible ML resistance phenotype accounted for 2.9% (3/104) of S. aureus and 3.2% (2/62) of CoNS. Among erythromycin-resistant isolates, single or various combination of different resistance genes were detected. The results of this study showed that ML resistance was prevalent among staphylococci from subclinical bovine mastitis cases in Hatay, Turkey. Therefore, a continuous surveillance is necessary to minimise the spread of antimicrobial-resistant staphylococci.