Investigation of the methicillin resistant Staphylococcus coagulans and Staphylococcus schleiferi in cats and dogs with otitis externa and pyoderma

In this Thesis study, it was aimed to investigate the presence of Staphylococcus schleiferi and Staphylococcus coagulans in cats and dogs with otitis externa and/or pyoderma using conventional and molecular methods, to investigate the presence of the mecA and pvl genes in the identified isolates, and to determine the antibiotic susceptibility/resistance profiles of the isolates against commonly used antibiotics in veterinary medicine. Materials were collected from a total of 101 infected animals, including 62 cats and 39 dogs, diagnosed with otitis externa and/or pyoderma at the veterinary clinics located in Afyonkarahisar and neighboring provinces. In this regard, a total of 189 swab samples were examined, comprising 100 ear swabs from 50 cats, 64 ear swabs from 32 dogs, and 25 skin swabs from 16 cats and nine dogs. Of the 113 Staphylococcus isolates isolated from the samples using classical culture methods, 111 were confirmed as Staphylococcus species by PCR using 16S rDNA genus-specific primers. Following the detection of the S. schleiferi/S. coagulans species-specific nuc gene for the identification of the isolates at the species level, urease and coagulase tests were performed on the isolates. Then, bidirectional Sanger sequencing analysis was used to definitively distinguish the two species. Of 111 Staphylococcus isolates, 1.8% (n=2) were typed as S. coagulans. These two isolates were obtained from two different dogs with otitis externa. While the S. coagulans isolation rate was determined to be 6.25% in 32 dogs with otitis externa, S. coagulans constituted 7.4% of the 27 Staphylococcus isolates isolated from these dogs. While the presence of S. coagulans was not detected in cats, S. schleiferi was not isolated from either animal species. The mecA and pvl genes were not determined in either of the two isolates identified to be S. coagulans. The Kirby-Bauer disk diffusion method was used in the detection of antibiotic sensitivity of the isolates. The phenotypic methicillin resistance was not detected in any of the S. coagulans isolates. However, one isolate exhibited resistance to penicillin, chloramphenicol, tetracycline, doxycycline, erythromycin, azithromycin, and clarithromycin. While one isolate was found to be susceptible to gentamicin and clindamycin, the other showed intermediate susceptibility to both antibiotics. The presence of multidrug resistance (MDR) in one of the S. coagulans isolates indicated the importance of antibiotic selection being carried out accurately and specifically, based on antibiotic susceptibility test results for the effective treatment of S. coagulans-related infections in veterinary medicine. In conclusion, although the isolation rates obtained in this Thesis study are low, this Thesis is the first study in Türkiye to reveal the presence of S. coagulans at the molecular level in dogs with otitis externa and to report the presence of MDR S. coagulans. Accordingly, the data obtained in this Thesis study are expected to contribute to both national and international scientific literature.