جستجوی مقالات مرتبط با کلیدواژه "ورم پستان" در نشریات گروه "دامپزشکی"

Mastitis is an inflammatory disease of the mammary gland, caused by many infectious agents such as bacteria, fungi, and viruses. Streptococci are reported to be among the major pathogens causing bovine mastitis around the world, which may cause clinical and subclinical forms of mastitis. Mastitis is one of the primary diseases of dairy cows and is responsible for remarkable economic losses due to reduction in quantity and quality of milk, cost of treatment, and the early culling of the cows. Considering the existence of substantial industrial and traditional dairy cattle farms in Chaharmahal and Bakhtiari province and the fact that mastitis is the most common disease in dairy industries, this study aimed to identify the role of streptococci in subclinical mastitis in dairy cows in Chaharmahal and Bakhtiari province. For this purpose,134 subclinical mastitis milk samples were collected from 8 dairy farms in Chaharmahal and Bakhtiari province, based on the california mastitis test (CMT) results and screened for the streptococcal cause of mastitis. DNAs were extracted from collected specimens and PCR was performed with specific primers for Streptococcus agalactiae, Streptococcus uberis, and Streptococcus dysgalactiae. Out of 134 mastitis milk samples 10 (7.5%), 14 (10.4%), and 5 (3.7%) samples were positive for S. agalactiae, S. uberis, and S. dysgalactiae respectively. The result of this research shows that 21.6 (29:134) percent of mastitis in dairy cattle farms in the studied region may be due to streptococci. The obtained data can be used in management and prevention strategies for cattle mastitis control in Chaharmahal and Bakhtiari province.

It has been determined that there is a direct relationship between the severity of mastitis and the virulence factors produced by bacterial agents. Identifying bacterial virulence factors is neccecary for designing suitable vaccines against mastitis. The aim of the present study was molecular diagnosis of selected virulence factors of endemic isolates of S. aureus involved in bovine mastitis. A total of 180 milk samples were collected from cows with clinical (37 samples, 20.6%) and subclinical (143 samples, 79.4%) mastitis from 8 semi-industrial dairy farms of Chaharmahal and Bakhtiari province, Iran. After culture and purification, coagulase, catalase and oxidase tests were performed. DNA was extracted from S. aureus suspected colonies. Final confirmation was performed using PCR test on the specific 23S rRNA gene of the bacteria. Thirty one (17.22%) out of the 180 collected samples were found to be positive for S. aureus by PCR, of which 2 cases were related to clinical mastitis and 29 cases were related to subclinical mastitis. The highest frequency of virulence genes was related to the Coa gene (90.32%), followed by ClfB (87.09%), LukD, and fnbB (80.64%), LukE (77.41%), fnbA (74.19%), Hla (48.38%). The lowest frequency was related to the Hlb gene (45.16%). Based on the obtained results, the diagnosis of the virulence factors of S. aureus has the potential of being used in the development of vaccines for the prevention of mastitis.

Mastitis is a well-recognized and costly disease of dairy cattle. Mycoplasma bovis is one of the most important causal agents of mastitis in dairy cows. In respect to the importance of mastitis caused by Mycoplasma, the objective of the present study was to evaluate of presence of M. bovis in bulk milk of dairy cattle farms of Hamedan province, Iran. For this purpose, a total of 125 bovine bulk tank milk samples were collected from 31 dairy farms of Hamedan, Iran. After that, California Mastitis Test (CMT) and Somatic Cell Count (SCC) were done on the milk samples. Then using DNA extraction kit, the total DNA was extracted from each sample. The PCR followed by nested PCR (nPCR) was performed for specific detection of M. bovis. Based on PCR for genus detection, totally, 19 out of 125 (15.2%) bulk tank milk samples were contaminated with Mycoplasma spp. In addition, 11 samples (8.8 %) were contaminated by M. bovis based on nested PCR results. Moreover, the results showed that 26 of 125 bulk milk samples (20.8 %) and 102 of 125 bulk milk samples (81.6 %) have high rate score by CMT and SCC, respectively. Statistical analysis showed a positive correlation between CMT and SCC results. In the present study, the presence of M. bovis in the bulk tank milk samples suggests that more hygiene practices are required to avoid transmitting this pathogen among dairy cow herds of Hamadan region. According to the presence of Mycoplasma in bulk tanks of this region, the present study suggested that the frequency of Mycoplasma contamination in individual cows be determined.

The increasing importance of antibiotic resistance shows the need for determining indices of the epidemiology of infection.

This study aimed to determine the virulence genes and antibiotic resistance profiles of Staphylococcus aureus isolated from bovine mastitis cases.

A total of 200 cattle were selected based on California Mastitis Test (CMT) results, and the samples were cultured in the laboratory. Grown colonies were examined by conventional phenotypic methods and confirmed using PCR amplification of 16S rRNA gene. The prevalence of the virulence genes was also defined. The results of phenotypic and molecular tests were compared using SPSS software by McNemar test. Then, the confirmed isolates were tested for antibiotic susceptibility using the disc diffusion method.

Of the 200 positive CMT cattle, 24 animals were positive for S. aureus and confirmed using 16S rRNA gene amplification. Statistical analysis showed that the phenotypic and genotypic tests of hemolysin genes were not significantly different (P>0.01). PCR analysis revealed the presence of coa and clfa genes in more than half of the cases. Overall, nine genetic profiles of virulence factors were found among S. aureus isolates. The highest and lowest resistance rates were against penicillin and gentamicin, respectively.

Our findings showed a high rate of antibiotic resistance. So, accurate and fast diagnosis and antimicrobial susceptibility tests should be considered before prescribing the drugs.

Methicillin-resistant Staphylococcus aureus (MRSA), affecting livestock and human beings, has become a global public health hazard with economic consequences.

The current study was designed to investigate the prevailing MRSA-associated subclinical mastitis and associated risk factors in dairy buffaloes. The study also highlighted the genetic variations and in silico-based proteomic differences among MRSA isolates.

Out of 516 milk samples, 45.93% (237/516) were found positive for subclinical mastitis, while the prevalence of S. aureus was recorded 56.12%. The methicillin resistance in S. aureus isolates was evaluated by oxacillin disc diffusion test and molecular identification of the mecA gene.

The results revealed a phenotypic and molecular prevalence of MRSA at 45.11% and 18.79%, respectively. The risk factor analysis revealed that among various assumed risk factors, parity, milking hygiene, milker care during milking, milk yield, housing system, and floor type were significantly associated with subclinical mastitis in buffaloes. The sequencing and phylogenetic analysis showed no significant genetic variations among study isolates and depicted a high similarity with isolates from Africa, USA, India, Italy, Turkey, and Iran. The in-silico protein analysis showed that all sequences had the same protein motifs resembling penicillin protein 2a except Buff-13, whose protein structure resembles alpha-catenin-like protein hmp-1.

The current study was the first report of the genotypic characterization and in silico protein analysis of MRSA from dairy buffaloes in Pakistan. The result highlighted the importance of antimicrobial resistance (AMR) and development of control strategies against MRSA infections.

Biofilm production by Staphylococcus aureus is a prevailing cause of multidrug resistance. The evolutionary mechanisms of adaption with host and pathogenicity are poorly understood.

The present study aimed to investigate the biofilm-forming potential, associated multidrug resistance, and the evolutionary analysis of S. aureus isolated from bovine subclinical mastitis.

122 S. aureus isolates were subjected to Congo red agar method (CRA), microtitre plate method (MTP), and PCR to check the biofilm-forming potential. The Kirby-Bauer disk diffusion method was used to evaluate the antibiotic resistance pattern. The icaA gene of isolates was subjected to molecular and evolutionary analysis using different bioinformatics tools.

The results showed that 63.93% of S. aureus isolates carried the icaA gene and the detection rate of CRA was higher (36.07%) compared to the MTP test (24.59%). A total of 78.21% and 56.41% of biofilm-positive isolates were methicillin-resistant S. aureus (MRSA) and vancomycin-resistant S. aureus (VRSA), respectively. All S. aureus isolates (100%) showed multidrug resistance. The molecular analysis showed an evolutionary link between isolates and revealed a strong codon bias, three different recombination events, and positive selection in some residues of the semi-conserved segments of the icaA gene.

The study concluded that biofilm-positive isolates have a high tendency to exhibit methicillin, vancomycin, and multidrug resistance. The findings suggest that mutation and selection are the most likely causes of codon bias in the icaA gene sequences. The variations led by recombination events and positive selection are suggestive of bacterial strategy to combat antimicrobial effects and to escape the host’s immune surveillance.

Staphylococcus aureus is responsible for many infections in humans and animals from skin and soft tissue infections to life-threatening diseases. In this study to explore the origin of S. aureus infections in humans, the antibiotic resistance profile and the variety of virulence factors in S. aureus isolates were examined in three groups: a healthy human population, cheese, and the milk of sheep with mastitis.

The examination of some virulence factors in S. aureus isolates obtained from the healthy human population, sheep mastitis, and cheese.

A total of 400 nasal swab samples from healthy students, 30 cheese samples, and 122 sheep milk samples were collected for the detection of S. aureus isolates from January 1, 2018, to March 1, 2018. The frequency of hla, hlb, Acme/arcA, pvl, and tsst-1 virulence genes and mecA gene was determined in each group by PCR assay.

There was a direct relationship between the antibiotic susceptibility profile of the isolates from a healthy population and those from mastitis milk samples. Of 400 nasal samples, 15% (60/400) were positive for S. aureus, of which 60% (36/60) were positive for mecA. While 50% (15/30) of cheese samples were positive for S. aureus. of which 7 cases (46.66%, 7/15) were positive for mecA. The prevalence of S. aureus among students was dependent on gender (P=0.025). Also, 47.5% (58/122) of milk samples from sheep mastitis were positive for S. aureus, and 41.37% (24/58) were positive for the mecA gene. Based on PCR results, the highest rate of hla (68.33%, 41/60), hlb (53.33%, 32/60), and Acme/arcA (46.66%, 28/60) genes were related to a healthy population, and the highest frequency of pvl (41.38%, 24/58), and tsst-1 (27.59%, 16/58) was related to milk samples (P<0.05). A significant correlation was observed between the presence of the arginine catabolic mobile element (ACME)-arcA gene and resistance to methicillin (P<0.05).

The high rate of virulence factors in the S. aureus isolates obtained from mastitis and dairy products is an alert point, because they could be source of the spreading of S. aureus to humans. There is an essential need for continuous monitoring to control staphylococcal food poisoning.

Antimicrobial resistance (AMR) is a burning issue in the present era. Mastitis in dairy animals is one of the most important causes of huge production loss to dairy farmers.

The study aims to find the prevalence, antimicrobial resistance profile, and resistance genes in the extended-spectrum beta-lactamase-producing Escherichia coli in mastitic milk.

A total of 125 milk samples were collected from Beetal goats suffering from clinical mastitis from different districts of Punjab and processed for bacterial isolation and further identification. The drug resistance profile of ESBL-producing E. coli and its associations with molecular markers was analyzed using statistical analysis.

The prevalence of ESBL-producing E. coli in dairy goats of Punjab was recorded as 6.4%. The isolates showed the highest resistance to the beta-lactam group of antibiotics. The resistance percentages of streptomycin, gentamicin, tetracycline, chloramphenicol, clotrimazole, and colistin were 50%, 37.5%, 50%, 25%, 25%, and 50%, respectively. The isolates showed intermediate resistance to imipenem (12.5%) and tetracycline (25%). The ESBL-producing E. coli isolates harbored the resistance genes blaCTXM (100%), blaTEM (62.5%), blaSHV (25%), blaOXA (37.5%), tetA (37.5%), tetB (25%), aadA (37.5%), sul1 (25%), MOXM (12.5%), DHAM (25%), and blaCMY-2 (50%). Tetracycline and sulphonamide resistances were statistically associated with their respective resistance genes (P<0.05). Streptomycin resistance was not statistically associated with the presence of the aadA gene (P>0.05). The genes blaIMP and blaNDM were not recorded in any of the isolates. In this study, 12.5% of the isolates showed co-resistance to colistin and carbapenem.

Antimicrobial resistance is a hot topic and requires immediate attention.

The present study was performed to assess the resistance profile to fluoroquinolone and to determine mutations in gyrA and parC genes of Escherichia coli in bovine coliform mastitis. Fluoroquinolones (norfloxacin (NOR), ciprofloxacin (CIP), enrofloxacin (NFX), levofloxacin (LEV), and ofloxacin (OFL) were tested against E. coli isolates, isolated from bovine mastitis (100 milk samples) by disk diffusion method. To determine the extent of gyrA and parC mutations associated with fluoroquinolone resistance in E. coli, two isolates with the highest resistance to each fluoroquinolone were submitted for the amplification and sequencing of the quinolone resistance-determining regions (QRDRs) of gyrA and parC genes. The disk diffusion method indicated that E. coli isolates had the highest intermediate resistance to OFL (16.7%), followed by NFX and NOR (15%), while they had low resistance to CIP and LEV (3.33%). A few silent mutations in gyrA (in codons 91, 100, 111, 131, 132) and in parC (in codons 91, 157, 159) were detected in QRDRs, and mutations in nucleotides 65, 80, and 83 in gyrA, and 195, 209, 212 in parC were detected in the other isolate. These results showed an intermediate rate of resistance to fluoroquinolones in E. coli isolates from raw milk of cows with coliform mastitis