Naslov
Agreement of conventional microbiological and molecular identification of streptococci isolated from bovine milk

Autori
Maćešić, Nino ; Fumić, Tihana ; Duvnjak, Sanja ; Bačić, Goran ; Cvetnić, Luka ; Karadjole, Tugomir ; Samardžija, Marko ; Habrun, Boris ; Lojkić, Martina ; Prvanović Babić, Nikica ; Efendić, Maša ; Cvetnić, Marija ; Benić, Miroslav

Izvornik
Veterinarski arhiv (0372-5480) 92 (2022), 4; 381-387

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
streptococci ; bovine mastitis ; culture ; molecular tools ; 16S rRNA

Sažetak
Pathogenic streptococci are implicated in clinical and subclinical mastitis. Most laboratories identify streptococci on the basis of microbiological examination, but molecular diagnostic methods have become the gold standard of mastitis diagnosis in the last few years. Therefore, this study aims to determine the agreement of microbiological and molecular identification of streptococci isolates from bovine milk. Milk samples were taken before the evening milking into sterile tubes. Samples were examined bacteriologically by inoculation on aesculin blood agar. Identification of grown colonies was carried out using internationally accepted methodology. Sequencing of the 16S rRNA gene was the reference method used to confirm Streptococcus sp. in all bacterial isolates. In the study, 54 strains of bacteria isolatedfrom milk samples from the udder quarters of dairy cows with subclinical mastitis were examined using molecular methods. By conventional microbiological examination, the strains were identified to the species (Strep. agalactiae, Strep. dysgalactiae and Strep. uberis) or the genus level (Streptococcus spp.) without final identification of the species. On the basis of 16S rRNA analysis, 47 out of 54 examined streptococcal strains were found to belong to the genus Streptococcus sp. Among the streptococci identified, 6 isolates belonged to Strep. agalactiae, ¸8 isolates to Strep. dysgalactiae, 2 isolates to Strep. canis and 31 isolates belonged to Strep. uberis. Among the seven remaining isolates, three were identified as Enterococcus faecalis and four as Lactococcus lactis. Agreement between the identification procedures used was fair, with a Kappa index of 0.2181 (SE=0.0612 ; Z=3.56 ; p=0.0002).

Izvorni jezik
Engleski

Znanstvena područja
Veterinarska medicina

POVEZANOST RADA