Browsing by Author "Ocak F."

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    Conventional and molecular biotyping of Brucella strains isolated from cattle, sheep and human; [Si{dotless}ǧi{dotless}r, koyun ve insanlardan izole edilen Brucella suşlari{dotless}ni{dotless}n konvansiyonel ve moleküler biyotiplendirmesi]
    (Chartered Inst. of Building Services Engineers, 2012) Iça T.; Aydin F.; Gümüşsoy K.S.; Perçin D.; Sümerkan A.B.; Ocak F.; Abay S.; Doǧan H.O.; Findik A.; Çiftci A.
    In this study, the role of Brucella spp. in cattle and sheep abortions among Kayseri region was investigated and predominant subspecies and biovars in this region were determined by conventional and molecular biotyping methods. For this purpose, 61 cattle and 64 sheep abortion material and also 50 human blood isolates were examined. A total of 29 Brucella spp. 17 (27.9%) and 12 (18.7%) of which were isolated from cattle and sheep specimens, respectively) were isolated from animal sources. Both animal and human isolates were typed by conventional and Enhanced AMOS-ERY PCR methods. All Brucella spp. strains isolated from cattle were found to belong to B. abortus biovar 3 and biovar 3b using conventional and molecular typing methods, respectively. All sheep originated Brucella spp. strains and human originated Brucella spp. strains were found to belong to B.melitensis biovar 3 using both conventional and molecular methods. As a result, predominant biovars causing brucellosis in human, cattle and sheep in Kayseri, Turkey were detected. These findings were considered to be useful in prevention and controlling activities for Brucellosis in Turkey.
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    Cryopreservation of Leishmania Species in Manisa Province
    (2017) Çavuş İ.; Ocak F.; Kaya T.; Özbilgin A.
    OBJECTIVE: It was aimed to assess the success of the cryopreservation process which is carried out in order to preserve the genetic material and the virulence of the Leishmania species that are an important health problem in our region.; METHODS: Leishmania tropica, L. infantum, L. major, and L. donovani strains in Novy-MacNeal-Nicolle (NNN) medium in MCBU were used. Promastigotes cultured in the NNN medium were transferred to RPMI 1640 medium; promastigotes in the logarithmic phase were washed three times with PBS, and 15% dimethylsulfoxide (DMSO) was added. Leishmania species were transferred to 12 separate tubes. The tubes were stored at -86°C for one night by placing them in Coolcell boxes. The tubes were transferred into a liquid nitrogen tank. One cryotube per Leishmania strain is thawed monthly and cultured in NNN medium.; RESULTS: For the duration of study it was observed that each Leishmania isolate preserved 60-65% of their viability and entered the logarithmic phase on the 7th day following the inoculation in the NNN medium. Abnormalities in the structures and movements of the promastigotes were not observed in microscopic examinations.; CONCLUSION: The following conclusions were made: cryopreservation is important for studies planned related to leishmaniasis and cryopreservation with DMSO is successful.
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    Determination of the most significant serotypes and antimicrobial susceptibilities of avian pathogenic escherichia col isolates in turkey; [Bestimmung der wichtigsten serotypen und der antibiotika-resistenz von pathogenen escherichia coli isolaten beim geflügel in der türkey]
    (Verlag Eugen Ulmer, 2018) Ocak F.; Çöven F.; Ertunç E.; Eğilmez T.; Türkyilmaz S.
    The present study aimed to isolate Escherichia coli from chickens with colibacillosis, to detect the presence of important serotypes (O1, O2, O18, O78) and to examine antibiotic susceptibility profiles and resistance genes in antibiotic resistant isolates in Turkey. A total of 150 E. coli isolates collected from internal organs of broilers with colibacillosis were used in the study. Antibiotic resistance status of these isolates to 12 antimicrobial agents that belong to 7 antimicrobial families was examined by the disk diffusion method. The most important 23 resistance genes in antibiotic-resistant isolates and important APEC (Avian pathogenic E. coli) serotypes were investigated by polymerase chain reaction (PCR). While 6.7% of the isolates were found to be susceptible to all antimicrobials, 66.7% were multidrug resistant. It was determined that 150 isolates of E. coli were resistant at a rate of 73.3%, 68.7%, 63.4%, and 60.7% to amoxicillin/ampicillin, tetracycline, enrofloxacin, and trimethoprim/sulfamethoxazole, respectively. The blaTEM, blaCMY, blaSHV, blaCTX, blaOXA, tetA, tetB, qnrA, drfA1, drfA7,17 and sulII antibiotic resistance genes were detected. It was determined that 18.0% of isolates were O78, 10.0% were O2, 2.7% were O1, and 2.0% were O18. It was concluded that further epidemiological studies should be designed to investigate the virulence properties and clonal groups of APEC. This study was the first research of serotypes and antibiotic resistance genes of APEC isolates in Turkey using molecular methods. © 2019, Verlag Eugen Ulmer. All rights reserved.
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    Investigation of Antimicrobial Resistance, Biofilm Production, Biofilm Associated Virulence Genes and Integron Genes of Pseudomonas aeroginosa Isolates Obtained from Animal Clinical Samples
    (Israel Veterinary Medical Association, 2022) Ocak F.; Turkyilmaz S.
    The results of antimicrobial treatment in Pseudomonas aeroginosa infections may depend not only on the antibiotic susceptibility of the etiologic agents, but also on the biofilm production and integron carrying capabilities of the bacteria. This study aimed to examine the relationship between antimicrobial resistance and biofilm production, biofilm related virulence genes, integron genes carried by P. aeroginosa isolates obtained from different animal clinical samples. A total of 67 P. aeroginosa isolates obtained from bovine mastitis, canine otitis and dermatitis cases were used as material. Bacterial identification was carried out using conventional methods. Qualitative (Congo Red Agar Test (CRA)) and quantitative (Microplate Test (MP)) methods were used to determine the phenotypic biofilm production capacity of the isolates. Polymerase chain reaction (PCR) was used to confirm the genus and species level identification of the isolates, and to identify biofilmassociated virulence genes and integron genes. The resistance patterns of the isolates against 12 antibiotics belonging to 6 antimicrobial families were examined using the disk diffusion method. Isolates resistant to at least three drug classes were defined as multi-drug resistant (MDR). The Chi-Square (χ2) test was used to compare the relationship between the MDR capacity of the isolates and biofilm formation, the prevalence of biofilm-associated virulence genes and the prevalence of integron genes. It was determined that 41.8% of the isolates as by qualitative method and 64.2% by the quantitative method were biofilm producers. The genes responsible for biofilm formation, ppyR, pslA and pelA, were detected in 94.0%, 83.6% and 65.7% of the isolates, respectively. 23.9% of the isolates carried the integron gene. Piperacillin tazobactam and ceftolozane tazobactam were found to be the most effective drugs against P. aeruginosa isolates studied. 28.4% of the isolates were MDR. As a result of this study, it was determined that MP was more effective than CRA in determining biofilm production phenotypically. While there was no significant relationship between MDR capacities with phenotypically biofilm formation, the prevalence of ppyR and pslA virulence genes, the relationship between the prevalence of pelA virulence gene and the presence of integron genes, was significant. © 2022, Israel Veterinary Medical Association. All rights reserved.
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    Detection of Mycoplasma spp. and Mycoplasma bovis DNA in Mastitic Cow Milk Samples by PCR
    (Israel Veterinary Medical Association, 2023) Ocak F.; Avsever L.; Turkyilmaz M.K.; Turkyilmaz S.
    Mycoplasma mastitis is a highly contagious disease of dairy cattle that generally does not respond to treatment, adversely affect milk yield as well as animal health, causing significant economic losses. Therefore, rapid and reliable identification of this pathogen is required to develop control strategies on farms. One of the most important mycoplasma agents causing mastitis is Mycoplasma bovis, an invasive agent. In this study, it was aimed to identify Mycoplasma spp. and M. bovis DNA by PCR, which are important mastitis pathogens but often neglected, in cow milk with mastitis. For this purpose, 312 milk samples with mastitis, 84 with clinical and 228 with subclinical mastitis, were investigated from 17 farms. DNA extraction from milk samples was carried out using the phenol chloroform method. Identification at the species and genus level were performed by polymerase chain reaction (PCR). In PCR, primers targeting 16S rDNA for Mycoplasma spp. and uvrC gene target regions for M. bovis were used. Mycoplasma spp. and M. bovis DNA were detected in milk samples at a rate of 19.6% (61/312) and 13.8% (43/312) respectively from 11 farms. The rate of M. bovis among all mycoplasmas was determined as 70.5% (43/61). Isolation of mycoplasmas, which are the causative agents of mycoplasma mastitis, by classical conventional methods tends to be long and laborious. Where mycoplasmal mastitis is suspected, bacterial DNA detection by PCR may be an ideal way to make a diagnosis in a short time. However, in order to develop accurate treatment strategies, it would be beneficial to examine all mycoplasma agents along with not overlooking other pathogens that could lead to mastitis. © 2023, Israel Veterinary Medical Association. All rights reserved.
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    Comparative study on genotypic properties of Pseudomonas aeruginosa isolated from subclinical mastitis in Türkiye
    (Hellenic Veterinary Medical Society, 2023) Ocak F.; Turkyilmaz S.
    The results of antibacterial treatment in mastitis may be related not only to the antibiotic sensitivity of the etiological factors but also to their abilities to carry integron and virulence genes. Integrons are mobile DNA elements that can capture and carry genes, particularly those responsible for antibiotic resistance. Pseudomonas aeruginosa has numberless virulence factors which are contributed to bacterial invasion and toxicity. This study aims to investigate antibiotic resistance, integron and virulence gene profiles of P. aeruginosa isolates obtained from cow milk with subclinical mastitis; further, was to evaluate the relationship between the antimicrobial resistance of bacteria with the integron and virulence gene carrying. The material of the study consists of 32 (9.8%) P. aeruginosa isolates obtained from 326 subclinical mastitis milk samples. After the bacterial identification by classical conventional methods, polymerase chain reaction (PCR) was carried out to confirm the genus and species of the isolates and to determine the integron and virulence gene profiles. Antimicrobial resistance was determined by the disk diffusion method using fifteen antibiotics belonging to eleven antimicrobial families. The relationship between the presence of integron and virulence genes associated with antibiotic resistance, further the relationship between the presence of virulence genes and antimicrobial resistance was calculated with the Chi-Square (χ2) test. Ten virulence genes (lasl, lasR, lasB, rhll, rhlR, rhlAB, plcH, plcN, ppyR, exoT) were found in all isolates whilst another virulence gene (aprA) was not present in any isolate. It was found that 34.4% of the isolates carried any integron gene. The results showed that the relationship is important between the presence of int genes and gentamicin, amikacin, tetracycline, cefoperazone, imipenem, aztreonam, ciprofloxacin, enrofloxacin resistance and exoU virulence gene presence. Also; there were also important associations between resistance to certain antibiotics and the presence of P. aeruginosa virulence genes. All isolates obtained in this study showed multiple antibiotic resistance (MDR). In these cases, showing the presence of integron and some virulence genes could play a prominent role in the resistance of P. aeruginosa isolates to antimicrobial drugs. This study may be important as it is the first study to show the presence of antibiotic resistance, integron and virulence genes together in subclinical mastitis cow’s milk isolates of P. aeruginosa in Türkiye. The presence of antibiotic-resistant P. aeruginosa strains in cattle farms may also pose a public health risk, as these bacteria can transmit their resistance genes to humans through food consumption © This work is licensed under a Creative Commons Attribution-NonCommercial 4.0.
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    Investigation of genetic relatedness, antimicrobial resistance, biofilm formation, biofilm-related virulence genes and integron-related genes of Stenotrophomonas maltophilia isolates obtained from bovine milk samples with mastitis
    (Hellenic Veterinary Medical Society, 2023) Ocak F.; Turkyilmaz S.
    Treatment of infections caused by the opportunistic pathogen Stenotrophomonas maltophilia is complicated by the bacterium’s ability to produce biofilms and high antibiotic resistance. This study aimed to investigate the prevalence of genetic relatedness, antimicrobial resistance, biofilm formation, biofilm-related genes with virulence and integron-related genes among isolates of S. maltophilia recovered from bovine milk with subclinical mastitis. In this study, bacterial identification was performed using conventional methods. The smeT gene-based Polymerase Chain Reaction (PCR) was used for bacterial identification. PCR was also used to detect virulence and integron-related genes, too. The quantitative Microplate Test (MP) method was used to determine the phenotypic biofilm production capacity of the isolates. The resistance patterns of the isolates against nine antibiotics belonging to nine antimicrobial families were examined using the disk diffusion method. Isolates resistant to at least three drug classes from various antimicrobial drug classes were defined as multi-drug resistant (MDR). The genetic linkage of S. maltophilia isolates was investigated by Enterobacterial Repetitive Intragenic Consensus (ERIC) PCR. Chi-square (χ2) test was used to reveal statistical difference between MDR and integron-related gene prevalances as well as biofilm formation capacity of isolates and biofilm-related virulence genes. In the study, a total of 312 milk samples with subclinical mastitis were taken from 27 farms. Ten isolates from five farms were phenotypically and genotypically identified as S. maltophilia. All isolates were resistant to cefepime and imipenem. 80% of the isolates carried at least one of the integron-related genes and 70% were MDR. The phenotypically biofilm-forming capacity identified in isolates was detected at 80%. The prevalence of the studied virulence genes was rpfF 60%, rmlA 70%, spgM and smf1 80%. There was no significant relationship between the biofilm-forming capacity of the isolates and the prevalence of biofilm-related virulence genes and MDR with integron-related genes. In the UPGMA analysis performed, a total of five genotypes were found, two single and three multiple according to 18% similarity coefficient. The presence of same isolates on the same farm and closely related isolates on different farms may suggest a clonal spread. ERIC-PCR can be useful in identifying S. maltophilia isolates with epidemic potential. S. maltophilia isolates were detected simply and quickly, using PCR based on the smeT gene, from bovine milk samples for the first time in Turkey. © 2023, F Ocak, S Turkyilmaz
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    The Relationship between Biofilm Formation and Multiple Antibiotic Resistance of Streptococcus Isolates from Bovine Milk with Mastitis
    (Israel Veterinary Medical Association, 2024) Ocak F.; Turkyilmaz M.K.; Turkyilmaz S.
    Due to the increase in multi-antibiotic resistance (MDR) among streptococci, which have the ability to colonize different surfaces and form biofilms, treatment options have begun to be limited in diseases caused by these bacteria. The success of antibacterial therapy in mastitis may be related not only to the antibiotic susceptibility of the etiological factors, but also to the biofilm formation capacity, which is one of the most important virulence factors in bacteria. The aim of this study was to investigate the relationship between biofilm production and multi-antibiotic resistance of streptococcal isolates obtained from cow's milk with mastitis. For this purpose, 71 streptococcal isolates obtained from 282 subclinical mastitis milk from 27 farms were used. After the isolates were obtained by conventional methods, polymerase chain reaction (PCR) identifications were carried out. While the biofilm forming capacities of the isolates were determined phenotypically by the microplate method (MP); resistance to nine antibiotics belonging to nine antimicrobial families was evaluated by disc diffusion tests. Isolates resistant to at least three or more antimicrobial drug classes were considered multi-antibiotic resistant (MDR). Pearson Chi-Square (χ2) test was used to examine the relationship between biofilm forming capacity of isolates and multiple antibiotic resistance. Of the 71 streptococci obtained, 42 (59.1%) were identified as S. uberis, 13 (18.3%) as S. agalactiae, 8 (11.3%) as S. parauberis and 8 (11.3%) as S. dysgalactiae. Fifty one (71.8%) of the isolates were biofilm producers. Biofilm production was found in 84.7% (11/13), 75.0% (6/8), 69.1% (29/42), and 62.5% (5/8) in S. agalactiae, S. parauberis, S. uberis and S. dysgalactiae isolates, respectively. The most common resistance was to tetracycline (70.4%), followed by clindamycin (39.4%), ampicillin and vancomycin (35.2%), erythromycin (33.8%), and cefotaxime (32.4%). While 67.6% of the isolates were susceptible to chloramphenicol, 91.5% to linezolid and levofloxacin, 43.7% were MDR. The rate of multidrug resistance was higher in S. agalactiae (84.6%) than in S. parauberis (50%), S. dysgalactiae (50%) and S. uberis (28.6%). A significant correlation was found between the biofilm forming capacity of the isolates and multiple antibiotic resistance (P=0.016). It was concluded that biofilm-forming isolates showed higher resistance to antibiotics. As a result of this study, it was determined that mastitic streptococci isolates have the ability to produce biofilms that can significantly affect the course of the disease, and significantly affect multi-antibiotic resistance. The high biofilm forming capacity of MDR streptococcal isolates (87.0%, 27/31) might designate their high pathogenic potential that may pose a threat to human health. © 2024, Israel Veterinary Medical Association. All rights reserved.
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    Investigation of Broad-Spectrum Beta-Lactamase Production, Antibiotic Resistance and mcr-1 Gene in Escherichia coli Isolates from Broilers
    (Israel Veterinary Medical Association, 2025) Ocak F.; Turkyilmaz S.
    The detection of extended-spectrum β-lactamase (ESBL) production and mobilized colistin resistance gene (mcr) in Escherichia coli isolates reveals the potential for developing bidirectional resistance to both extended-spectrum β-lactamases and critically important colistin. The risk of transmission of these resistant bacteria from animals to humans can cause serious difficulties in terms of public health and veterinary medicine. This study was aimed to investigate the antibiotic resistance profiles of ESBL-producing E. coli isolates obtained from broilers with colibacillosis in the western part of Türkiye, the main ESBL genotypes (blaTEM, blaSHV, blaOXA, blaCTX-M) and the mcr-1 gene, one of the important genetic determinants of colistin resistance. In the study, 247 (75%) E. coli isolates obtained by classical conventional methods from 327 colibacillosis suspected broiler livers brought to the laboratory for routine diagnosis within the scope of various studies during the last year were used. Bacterial identification was done by classical conventional methods. ESBL-producing isolates were phenotypically confirmed with CHROMagar™ ESBL. Genotypes and mcr-1 genes of ESBL-producing isolates were examined by polymerase chain reaction. Antibiotic resistance profiles of the isolates against 20 antibiotics belonging to nine antimicrobial families were evaluated by automated microbiology system (BD Phoenix, Becton-Dickinson, USA). Isolates resistant to at least one antibiotic from three or more antibiotic classes were considered as multidrug resistant (MDR). ESBL prevalence in isolates was determined as 27% (66 isolates). The most common ESBL gene was blaTEM (53%), and blaCTX-M (27%), blaSHV (8%) and blaOXA (5%) genes were also detected. All ESBL-producing isolates were determined to be MDR. All of the isolates were resistant to tigecycline, 97% to ampicillin and 91% to ciprofloxacin. The highest susceptibility was observed against amikacin, ertapenem, imipenem and meropenem (100%). In addition, the mcr-1 gene was detected in 12% of the ESBL-producing isolates. These results showed that ESBL production was high in E. coli isolates obtained from broilers, the blaTEM genotype was more dominant than other genotypes and the blaTEM genotype showed an increasing prevalence. The fact that all ESBL-producing isolates were MDR displayed the difficulty of treating these bacteria. The coexistence of ESBL and plasmid-mediated colistin resistance genes revealed that these bacteria pose a serious risk to public health. © 2025, Israel Veterinary Medical Association. All rights reserved.