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    Identification of Enterococcus spp. and Lactococcus spp. Strains Isolated from Bovine Mastitis by MALDI-TOF MS and Evaluation of Antimicrobial Resistance Profiles
    (2024) Ötkün, Songül; Oğuz, Ayda Nur; Yıldırım, Ferhat; Tel, Osman Yaşar
    Mastitis is an important problem affecting animal health, welfare, and economy. Bacterial agents play a dominant role in the disease. The role of enterococcal and lactococcal species among environmental bacterial agents in mastitis has been underestimated due to inadequate identification. The aim of this study was to isolate and identify Enterococcus spp. and Lactococcus spp. from mastitic bovine milk and to evaluate the agents phenotypically in terms of antimicrobial resistance. A total of 108 milk samples from cattle with suspected mastitis were analyzed for enterococci and lactococci by standard microbiological techniques and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). By standard microbiological methods, 38 (35%) Enterococcus spp. and 13 (12%) Lactococcus spp. were isolated and identified from 51 milk samples. In species-level identification with MALDI-TOF MS, six different enterococci and three different lactococci were identified within acceptable score ranges. In antibiogram tests performed with the standard Kirby-Bauer method using 10 antimicrobials, 26% of the Enterococcus spp. and 46% of the Lactococcus spp. were resistant to at least 50% of the antimicrobials tested. In Enterococcus spp., the highest resistance rates were observed for enrofloxacin (79%) and ampicillin + cloxacillin (71%), while the best sensitivity (100%) was obtained for penicillin and ampicillin. In Lactococcus spp., the highest resistance rate was observed for enrofloxacin (85%) and amoxicillin + clavulanic acid (70%) and the best sensitivity (100%) was obtained for penicillin, ampicillin, and gentamicin. As a result, it was concluded that the diversity and high rate of antimicrobial resistance of enterococcal and lactococcal species in mastitis isolates poses a serious potential threat to animal and public health.
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    Investigation of the Effectiveness of Chromogenic Media in the Isolation of Pasteurella multocida and Mannheimia haemolytica from Calf Nasal Swab Samples
    (2022) Tel, Osman Yaşar; Ötkün, Songül; Yücetepe, Ayfer Güllü; Keskin, Oktay
    Accurate and rapid diagnosis of disease agents is the most important step in terms of control practices. Chromogenic media are culture media that allow the formation of colonies in colors specific to target microorganisms. Because they are target-specific, they do not require valida- tion of results but provide ease of use and time savings. In this study, it was aimed to evaluate the effectiveness of a chromogenic medium (Pasteurella BDR kit) in the detection of Pasteurella multocida and Mannheimia haemolytica agents in the Pasteurelleceae family, which cause respi- ratory disease in cattle. In this study, nasal swab samples taken from calves showing symptoms of respiratory disease were cultured in chromogenic and standard media. Suspicious growing colonies were confirmed by polymerase chain reaction for P. multocida and M. haemolytica. While 31 (36.9%) samples formed colonies with the chromogenic medium in the color specific to the target bacteria, 28 (33.3%) samples were positively determined for the target bacteria using the standard cultural method. The results of 26 samples were positive by both cultural diagnosis methods. When the results were compared with the traditional cultural diagnosis, agreement was found to be 92.86%. All colored colonies grown on the chromogenic medium were also tested by polymerase chain reaction (PCR). It was determined that the chromogenic medium detected P. multocida at a rate of 92.86% (n = 26) and M. haemolytica at a rate of 100% (n = 2) by forming colo- nies with a family-specific color. As a result, it was concluded that the use of chromogenic media is beneficial in the practical, rapid, and high-accuracy diagnosis of target agents.
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    Siirt ve Şanlıurfa’da Bulunan Bal Arılarında Nosemosis Etkenlerinin Moleküler Teşhisi
    (2021) Tel, Osman Yaşar; Ötkün, Songül; Yücetepe, Ayfer Güllü; Gürbilek, Sevil Erdenliğ; Keskin, Oktay
    Nosemosis bal arılarında (Epis mellifera) sıkça görülen küresel bir hastalıktır. Hastalığın etkeni fungalmikroorganizmalar olan Nosema apis ve Nosema ceranae’dir. Bu çalışmada Siirt ve Şanlıurfa’da bal verimidüşük ve zayıf (popülasyonu düşük) arı kolonilerinde Nosema spp. sporlarının varlığının mikroskobik olarakmuayene edilmesi ve pozitif bulunan örneklerden, multipleks PCR (Polimeraz zincir reaksiyonu) ile etkenin türdüzeyinde tespiti amaçlandı. Her iki ilde toplam 8 arılıkta 44 kovandan alınan 880 arı numunesi mikroskobikolarak spor varlığı yönünden incelenmiş ve 19’unda (%43,18) nosema sporları tespit edilmiştir. Multipleks PCRile bu sporların tamamının N. ceranae olduğu belirlendi. Sonuç olarak, nosemosis’in bölgede arıcılıkişletmelerinde önemli bir problem olduğu, bu nedenle nosemosis yönünden gerekli tedbirlerin alınmasıgerektiği kanısına varıldı.
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    The Isolation and Examination of the Host Specificity of Local Bacteriophages for Use Against Brucella abortus
    (2023) Ötkün, Songül; Erdenlig, Sevil; Saytekin, Ahmet Murat
    Bacteriophages are viruses that infect bacteria. Although their effects on bacteria have been known for many years, the discovery of antibiotics has limited the widespread use of bacteriophages against bacterial infections. However, it is now essential to reconsider using phage therapies due to antimicrobial-resistant bacteria and uncontrolled bacterial zoonotic diseases becoming a global problem. This study aimed to isolate lytic phages against B. abortus, the most common agent that causes bovine brucellosis, which has become a worldwide animal and public health problem. This performed isolation is from cattle farms known to be previously or currently infected, and the study also evaluates the lytic effects of these phages on B. abortus, B. melitensis, B. suis biotypes, B. ovis and B. neotomae and B. abortus field isolates in our culture collection. In this process, seven local brucella-specific phages were identified by evaluating 112 samples via general phage isolation and purification. The lyticity of the isolated bacteriophages were analyzed with international reference: B. abortus (bv 1, 2, 3, 4, 5, 6, 9), B. melitensis (bv 1, 2, 3), B. suis (bv 1, 2, 3, 4, 5) biovars, B. ovis, B. neotomae and B. abortus field strains (n:20). It was found that 85% of B. abortus strains produced a lysis pattern like Tbilisi ? through local phages. In terms of the lysis results, three different B. abortus specific phages were isolated (98 ?, 104 ?, and (P35, P70, P94/1, P94/2, P94/3) phages). It is thought that the applying cocktails prepared from these phages to fight against brucellosis will significantly contribute to controlling the disease. Since 15% of the field isolates were found to be rough strains, it is recommended that R/C ? are included in the prepared cocktails.