جستجوی مقالات مرتبط با کلیدواژه "bovine mastitis" در نشریات گروه "دامپزشکی"

Mastitis is the most important economic disease threatening the dairy industry in the world. Escherichia coli are one of the major causes of mastitis, which is treated with antibiotics, especially β-lactams. The emergence and spread of resistance to antibiotics in livestock, as well as the possibility of transferring this resistance to humans, is a serious threat to public health in different communities. The present descriptive-cross-sectional study was conducted to determine the frequency of resistance to beta-lactams in Escherichia coli isolates from cases of bovine mastitis in Tabriz and also evaluate the presence of blaTEM gene in the isolates. For this purpose, 240 milk samples from cows with clinical mastitis were collected from different regions of Tabriz, Iran. First, the isolates obtained from the samples were identified based on standard microbiology methods, and their antibiotic sensitivity was evaluated by the disc diffusion method. Then, the confirmatory test of beta-lactamase enzyme producers was performed by the combined disc method. Finally, the presence of blaTEM gene in beta-lactamase-producing isolates was investigated using polymerase chain reaction (PCR). Based on the findings, E. coli was isolated from 50 milk samples of mastitis (20.83% of the samples). Also, in the phenotypic method, 22 isolates (44% of the isolates) were detected as beta-lactamase-producing. The molecular results also showed that only 7 of beta-lactamase-producing isolates in the phenotypic method had the blaTEM gene. Considering the high frequency of beta-lactamase-producing E. coli in the present study and the possibility of the spread of antibiotic resistance in the livestock population, as well as the possibility of transmission of resistance genes to humans, accurate identification and treatment of animals suffering from mastitis seems necessary.

Pseudomonas aeruginosa is an important opportunistic pathogen that causes subclinical mastitis resistanted to treatment in lactating dairy cows. The aim of this research was to study the frequency of gyrB and oprL genes in Pseudomonas aeruginosa isolated from bovine mastitis in Maragheh city in 2022. In this descriptive cross-sectional study, 60 samples of Pseudomonas aeruginosa isolated from bovine mastitis which were identified by biochemical and staining tests. The samples were analyzed for the presence of the genes by PCR. Based on the results, the frequency of gyrB and oprL genes were observed in 10 (16.7%) and 3 (5%) isolates, respectively. Also, 3 isolates (5%) harbored both gyrB and oprL genes simultaneously. According to the results of this study, control of infection sources in mastitis caused by Pseudomonas aeruginosa is emphasized in order to control and prevent transmission of this bacterium.

Mastitis is known as the most economic important disease in the dairy industry in the world. Escherichia coli (E. coli) is one of the major causes of mastitis, which is treated with antibiotics, especially β-lactams. The emergence and spread of resistance to these antibiotics in livestock and the potential transfer of this resistance to human communities is a serious threat to public health in different countries.

This study aimed to determine the resistance to β-lactams in E. coli isolates from the milk samples of bovine clinical mastitis in Tabriz City, Iran. Also, the presence of the extended-spectrum β-Lactamase (ESBL)-encoding genes (blaTEM-1 and blaSHV-1) was investigated in the isolates.

In this descriptive cross-sectional study, 240 milk samples were collected from cattle with clinical mastitis in Tabriz. None of the cattle were under antibiotic therapy before sampling. The samples were evaluated according to the standard microbiological methods. The antibiotic susceptibility of E. coli isolates was investigated using the disk diffusion method. Also, the isolates were evaluated for the production of ESBL using the combined disk test. Finally, the presence of blaTEM and blaSHV in β-lactamase producing strains was confirmed using the PCR method.

Out of 240 samples, E. coli was isolated from 50 samples (20.83%), of which 22 isolates (44%) were detected as β-lactamase producers. The results of the PCR test showed that seven isolates (31.81 %) carried the blaTEM and four (18.18 %) the blaSHV.

Considering the abundance of β-lactamase-producing E. coli in this study, there is a possibility of the spread of antibiotic resistance among the livestock population due to improper use of antibiotics and transferring resistance genes to human communities. Therefore, accurate identification, proper treatment of infected animals, and compliance with the withdrawal period of animal products treated with antibiotics are recommended.

Pseudomonas aeruginosa is an important opportunistic pathogen that causes subclinical mastitis resistant to treatment in lactating dairy cows. Examination of the genetic pattern of isolates is necessary for the management of infections caused by this bacterium. The aim of this study was to investigate the genetic diversity of Pseudomonas aeruginosa isolates obtained from bovine mastitis in Tabriz city. In this cross-sectional descriptive study, sampling was done from 200 cows suffering from mastitis in cattle farms in Tabriz city. After performing specific biochemical tests and staining, positive cases were used for molecular tests. From a total of 200 cases of cows suffering from mastitis, 90 isolates (45%) of Pseudomonas aeruginosa were identified. The results of RAPD-PCR showed that 80 isolates (88.9%) of the studied samples could be typed with the primer used, and 10 isolates (10%) were not typed. The typed isolates were in 14 distinct groups and each one contained several samples of Pseudomonas aeruginosa. Groups I and VII harboured the most isolates and groups IX, X and XII contained the least isolates. Based on the results, RAPD-PCR technique was found as a useful tool to investigate the genetic variation for P. aeruginosa strains. This technique is a rapid and low cost genotypic method with high discriminatory power. According to the results of this study, it is emphasized to control the sources of infection in mastitis caused by P. aeruginosa, in order to control and prevent the transmission of this bacterium.

Staphylococcus aureus is one of the most important causes of contagious mastitis in domestic animals. Due to the existence of multiple strains of S. aureus and strain variations in chromosomal allelic rearrangement, different genotyping methods, such as analysis of the chromosomal DNA following the enzymatic digestion, are introduced for genetic typing of the bacterium. In the present survey, for the first time, the genetic diversity of S. aureus recovered from clinical bovine mastitis in Sanandaj was investigated based on PCR-RFLP analysis of the aroA gene. 120 bovine mastitic milk samples were collected aseptically and assessed. S. aureus isolated in culture and routine bacteriological methods were analyzed by aroA gene-based PCR. The amplicons with a size of 1153bp were digested with TaqI restriction enzyme and the fragments were electrophoresed. 28 S. aureus strains were isolated in phenotypic method among which the expected amplicon was observed in all of them. In enzymatic digestion, two RFLP patterns, nomenclatural based on the previous studies were generated. Genotype B was detected in 23 (82.14%) isolates and genotype N in 5 isolates (17.85%). The results demonstrate that S. aureus is involved in bovine mastitis in Sanandaj and despite the presence of limited genotypes, strain variation of this bacterium exist in the region. The presence of genotype B in all farms implies the same source of infection among farms, which should be considered in control programs of mastitis. Non-detection of universal genotype A and specific genotype of the bacterium in Sanandaj is reported for the first time.