Browsing by Publisher "Israel Veterinary Medical Association"

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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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    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.