Veterinary Research Forum

Abstract This study was conducted in West Azerbaijan province, Iran (37°27'18.022" N, 45°0'0" E) to investigate the genotyping and phylogenetic characterization of Mannheimia haemolytica in cattle and buffaloes from November 2022 to January 2024. Mannheimia haemolytica is a bacterium known to cause pasteurellosis pneumonia, a respiratory disease in ruminants, such as cattle and sheep. This is one of the main causes of economic losses in the feedlot industry. In addition to the deaths, treatment costs are also significant. The lung and nasal swab samples were collected from 378 cattle and buffaloes. The M. haemolytica was detected in 32 (8.46%) of the samples, with a notably higher isolation rate from lung tissue (56.25%; n = 18) compared to the nasal swabs (43.75%; n = 14). Interestingly, the study also revealed a seasonal pattern, with the highest isolation rates observed during January, February, and March. Multi-locus sequence typing demonstrated that all isolates belonged to sequence type 1 (ST1) within clonal complex 28. This finding is consistent with the global prevalence of ST1 in bovine isolates, indicating widespread distribution. Phylogenetic analysis revealed a strong correlation between ST1 and STs 30 and 54, highlighting the prevalence of ST1 in M. haemolytica among ruminants in West Azerbaijan, Iran. Further research is needed to investigate its potential for causing disease and its transmission pattern.

Abstract The most serious problem in public health is salmonellosis, a common disease in horse. The aim of this study was to investigate the shedding of Salmonella serotypes in healthy Caspian pony. We examined 143 pony's fecal samples collected from the north of Iran belonging to different ages and sexes. Samples were cultured, then identification of isolates were performed by common bacteriological methods and polymerase chain reaction (PCR). The PCR was also used to explore the presence of fimA and salmonella secreted effector L (SseL) genes as virulence factors in the isolates and all were assigned to antibiotic susceptibility test via disc diffusion method. Results showed two fecal samples (1.39%) contaminated with Salmonella and further examination demonstrated the isolates belonging to S. enterica serotype typhimurium. Both serotypes were isolated from female and ˂6 years of age group of ponies and we detected fimA and SseL genes in the isolates. Observing multiple drug resistance and virulence genes in isolates is of utmost importance from both clinical and public health perspectives. It is highly likely that we face instances of salmonellosis in animals or humans that lead to severe infections and fail to respond to treatment in future. This study revealed that the occurrence of Salmonella was low in ponies, however, regarding the presence of virulence factors with multidrug resistant trend in this zoonotic bacterium, establishment of good hygienic measurement to prevent the transmission of bacteria between animal and human is necessary. 

Abstract Staphylococcus aureus is an important pathogen causing a wide range of diseases in both humans and animals. The aim of this research was to screen the vancomycin resistance-associated genes in methicillin-resistant Staphylococcus aureus (MRSA) isolates from animals. A total of 400 nasal swab samples were collected from cattle, goats and sheep between February and August 2022 from both industrial and traditional livestock farms in West Azerbaijan province, Iran. Then, nasal swabs were cultured on mannitol salt agar and molecular analysis was performed after bacteriological examination to confirm the presence of S. aureus. The MecA gene was used to detect MRSA isolates, and two important vancomycin resistance-associated genes, namely vanA and vanB, were searched in the isolates. Out of 400 nasal swabs, 69 samples had S. aureus; of which seven isolates were resistant against methicillin. No vancomycin resistance-associated genes were detected in the MRSA isolates. Based on these findings, vancomycin could be used to treat infections caused by this bacterium.

Abstract The genetic diversity of Brucella strains has not been fully understood. To investigate this, the genetic characteristics of 64 isolates of Brucella melitensis from sheep and goats’ milk were studied using random fragment length polymorphism (RFLP) and multiple locus variable-number tandem repeat analysis (MLVA-16) methods developed in Orsay, France (MLVA-16_Orsay). The RFLP analysis revealed that all 64 isolates were of biovar one. The MLVA-typing showed that one sample was simultaneously infected with two strains of B. melitensis and the genotype of 65 isolate was analyzed. Four genotypes (47, 42, 43, and 63) were identified using MLVA-8 (panel 1), whereas six genotypes (138, 125, 116, 108, and two unknown genotypes) were identified using MLVA11 (panels 1 and 2A). From the review of MLVA-16 (panels 1, 2A, and 2B), panel 2B showed a very high discriminatory power. Two loci of Bruc04 and Bruc30 from this panel had diversity index values higher than 0.71 and the average diversity index was 0.619. So MLVA-16_Orsay 34 showed the genotype indicating a low genetic homogeneity among the isolates. The findings of MLVA genotyping of the isolates suggest that strains of B. melitensis isolated from the milk of small ruminants in Iran are most closely related to the isolates from neighboring countries of the Eastern Mediterranean group. To the best of our knowledge, this is the first study to indicate the potential use of MLVA genotyping for simultaneous detection of specimen contamination using two different B. melitensis biovars.

Abstract The aim of our study was to evaluate the effects of chitosan as immune stimulator on some hematological parameters and stress resistance in rainbow trout. Nine hundred rainbow trout (with initial body weight of 25 ± 0.1 g) were obtained from a local farm and acclimated to the laboratory conditions for one week. After that fish were randomly divided into four groups in three replicates. Each group received chitosan in diet at four concentrations as 0 (Control), 0.25, 0.5 and 1 percent chitosan, respectively. The trial was conducted for 8 weeks then feeding with chitosan stopped for 3 weeks later and during this time all fish were feed by control diet. The sampling was conducted to assay the hematological parameters of all groups every two weeks. In this study we assayed the resistance of fish against some environmental stresses immediately after changing the diet to the control. The results showed that using 0.25 percent chitosan in trout diets had a significant effect (P < 0.05) on hematological indices and stress resistance of rainbow trout in comparison the control group. Serum glucose level was higher in all treatment than control without any significance difference (P < 0.05). Based on the obtained results it concluded that the adding chitosan at 0.25 percent into the diet could enhance the hematological parameters and resistance against some environmental stresses in rainbow trout.

Abstract This study was performed from February to April 2006; several visits were made to abattoirs in the north of Iran for Hypoderma spp infestation. Necropsy inspection of slaughtered and skinned animals were carried out by examination of the inner skin surface and subcutaneous tissues. Warbles were isolated by squeezing nodules from subcutaneous tissues. In the case of abscess presence, aseptic sample were taken from abscesses. The parasitological and bacteriological examinations were performed on the samples. The results indicated that 104 out of 958 of slaughtered animals were infested to Hypoderma spp in which 48 (46.15 %), 34 (32.69 %) and 22 (21.15 %) were infested to Hypoderma bovis, Hypoderma lineatum and both species, respectively. Following bacterial analysis, the following bacteria were isolated: Escherichia coli, Streptococcus pyogenes, Staphylococcus aureus, Staphylococcus epidermidis and Klebsiella pneumonia.