Determination of Diversity, antimicrobial susceptibility patterns, biofilm formation ability, and risk factors of Staphylococcus species isolated from dogs and cats both healthy and with otitis externa

In this thesis, ear swab samples were taken from 50 cats and 50 dogs diagnosed with otitis externa and 50 healthy cats and 50 dogs brought for vaccination, shaving or neutering. Staphylococcus spp. were isolated from 67 (33.5%) of 200 animals. As a result of MALDI-TOF MS analysis, 29 of the Staphylococcus spp. isolates were identified as S. felis, 27 as S. pseudintermedius, 3 as S. aureus and 2 as S. simulans. Only one isolate was identified as S. schleiferi, S. haemolyticus, S. epidermidis, S. lugdunensis, S. pettenkoferi and S. sciuri. The highest rate of S. felis was isolated from cats (n:27, 75%), while the highest rate of S. pseudintermedius was isolated from dogs (n:24, 77.41%). The highest rate of resistance to tetracycline (n:16, 23.88%) was detected. This was followed by penicillin and ampicillin (n:15, 22.38%), erythromycin (n:14, 20.89%), clindamycin (n:11, 16.41%), oxacillin (n:7, 10.44%), cefovesin, ciprofloxacin and trimethoprim/sulfamethoxazole (n:5, 7.46%), amoxicillin-clavulanic acid, cefoxitin, gentamicin and enrofloxacin (n:4, 5.97%), rifampin and chloramphenicol (n:3, 4.47%). No resistance to amikacin was detected in the isolates. Inducible clindamycin resistance was detected in 3 (4.47%) isolates. Methicillin resistance (MRS) was detected in 9 (13.43%) isolates. mecA gene was detected in 6 isolates. Multidrug resistance (MDR) was detected in 12 isolates (17.91%). Biofilm production was detected in 64 (95.52%) of Staphylococcus spp. strains. Strong biofilm production was detected in 96.30% (26/27) of S. pseudintermedius strains, while weak biofilm production was detected in 55.17% (16/29) of S. felis strains (16/29). No significant relationship was found between MRS and MDR and biofilm production (p=0.99). However, there was a significant correlation between resistance to penicillin, ampicillin, and tetracycline and biofilm production (p<0.05). Although "antimicrobial use in the family", "family member with acne", "previous antimicrobial use in the cat/dog", "current antimicrobial use in the cat/dog" were found to be significant risk factors for both MDR and MRS (p<0.05), the variable "children at home" showed a significant effect only for MRS (p=0.020). In conclusion, the increasing number of MDR-MRS strains being reported from all over the world and the identification of intensive antibiotic use and contact between animals and humans as important risk factors associated with this resistance in this study indicate that this resistance can be transmitted between the agent, environment and individuals. Therefore, it was concluded that treatment should be based on antibiotic susceptibility test results rather than empirical treatment, resistance profiles should be continuously monitored and antibiotic use in animals and humans should be restricted.