نشریه میکروبیولوژی دامپزشکی
سال یازدهم شماره 1 (پیاپی 30، بهار و تابستان 1394)

In order to study the antibacterial effect of Zataria multflora، Thymus daenensis، Althea officinalis، and Urtica dioica، chicken Escherichia coli (E. coli) isolates sensitive to enrofloxacin (ENR)، Sulfadimidin-trimetoprim (Sul-trim)، Florfenicol (FLO)، Flemequine and Gentamycin were used. After the preparation of extracts from herbal plants، the antibacterial sensitivity of herbal plants with different concentrations (100، 50، 25، 12. 5 and 6. 25%) was assayed by disc diffusion test. Also، propylene glycol as negative control and commercial antibacterial drugs comprising ENR، Sul-trim and FLO as positive control were used and compared with herbal plant extracts for antibacterial sensitivity. The results showed maximum growth inhibitory diameter for E. coli induced following usage of florfenicol، 100% and 50% concentration of Zataria multflora and، Thymus daenensis extracts، respectively. The 50% and 100 % concentrations of Althea officinalis، and Urtica dioica extracts could induce growth inhibitory diameter the same as ENR and Sul-trim. The overall، results showed Zataria multflora، Thymus daenensis، Althea officinalis، and Urtica dioica have degrees of antibacterial effect and these herbal plants can be used as an antibacterial supplement in the treatment of avian colibacillosis. Therefore، the phytochemical analysis for complementary study is necessary.

The purpose of this study is to evaluate humoral immunity response in broiler chickens with mixed Eimeria infection، before and after treating by Salinomycin. The relation between the antibody titer and oocyst shedding was also investigated. Forty Ross 308 chicks were divided into 5 groups including 2 infected groups which had been fed with drug، 2 infected groups without treatment، and one as negative control. One of the infected groups was selected from Mazandaran (denoted as category1) and the other from Hamedan (denoted as category2). The antibody titer was assessed using ELISA test. In treated chickens of category 2، OPG (oocyst per gram) had a more significant difference (P≤ 0/05) than non-treated chickens of the same category. While in category 1، there was no significant difference for this index. The results showed more virulence in category 2 compared to category 1. There was a significant difference of OD (optical density) in the negative control group compared to the other four groups (P≤ 0/05). Both groups fed with oocysts showed stimulation of the immunity system to generate antibody، however its amount was not affected by Salinomycin. The results showed that there is no significant relation between oocyst shedding and antibody titers.

In this study، serum samples from 188 slaughtered water buffaloes were collected from Ahvaz abattoir during 2010-2011. The collected sera were analyzed by two commercial Elisa kits (IDEXX and ID VET) and NAT method. Seroprevalence of N. caninum in commercial kits IDEXX and ID VET and NAT method were 55. 9%، 66. 5% and 56. 9% respectively، which was significantly higher in ID VET Elisa kit in comparison with IDEXX Elisa Kit and NAT method، but there was no significant difference between IDEXX Elisa Kit and NAT method. Agreement between ID VET Elisa kit and IDEXX Elisa kit and NAT method was weak، and Kappa statistic for these associations were 0. 36 and 0. 26 respectively، but agreement between IDEXX Elisa kit and NAT method was moderate (Kappa statistic = 0. 59). Seroprevalence of neosporosis according to IDEXX Elisa kit in female and male water buffaloes were 59. 7% and 53. 7% respectively. Seroprevalence of neosporosis in water buffaloes with age of 2 years and lower and with age of more than 2 years were 57. 3% and 53. 1% respectively. Relationship between age and sex of water buffaloes and infection with N. caninum was not significant (P>0. 05).

Food-borne diseases are one of the major concerns of food and drug administration (FDA) and world health organization (WHO). Up to the present day، more than 250 types of food-borne diseases have been described and bacteria are responsible for two-third of them. Bacterial food poisoning is one of the most common food-associated diseases that are usually related to the consumption of contaminated foods with toxigenic bacteria. Among the bacterial agents responsible for food poisoning، staphylococcus aureus is the most common food poisoning agent worldwide. Milk and dairy products are the most common foods associated to staphylococcal food poisonings. Therefore، this study was considered to investigate the prevalence of enterotoxigenic isolates of Staphylococcus aureus in bovine and sheep bulk tank milk samples of Maku city. In this study، a total of 178 milk samples including bovine (n=92) and sheep (n=86) milk samples were collected. A total of 76 isolates from milk samples was examined for the production of staphylococcal enterotoxins and associated genes using Reverse Passive Latex Agglutination (RPLA) and Multiplex PCR (Polymerase Chain Reaction) respectively. Out of 44 and 32 isolaes from bovine and sheep bulk tank milk samples 19 (43. 1%) and 13 (40. 6%) were enterotoxin producers respectively. SEA، SED and SEC were the most common toxins detected in all isolates. The prevalence of classical enterotoxins and related genes are shown by SET-RPLA and m-PCR corresponded in 91. 1% of all S. aureus isolates، analyzed by both methods. Non-correspondence was observed in two sea positive isolates that were SEA negative، and in one isolates that were SEA and SEC positive only genes for sec were detected. This study indicated a high incidence of enterotoxigenic isolates of staphylococcus aureus in bovine and sheep bulk tank milk samples in Maku city.

Foot and mouth disease (FMD) caused by FMD virus is the most contagious disease of mammals and has a great potential for causing severe economic loss in susceptible cloven-hoofed animals. According to the absence of reciprocal protection among all the serotypes it is difficult to control FMD through vaccination. Therefore in order to prevent spread of FMDV، antiseptics are considered by world health authorities. This study was designed to investigate the antiviral properties of MgO nanoparticles as a disinfectant. Different concentrations of MgO nanoparticles were prepared in RPMI 1640 media and exposed to cell culture (Iran-Razi-Khedmati Bovine Kidney cell line). Cell toxicity was determined by MTT assay. Different concentrations of FMDV (O serotype) were treated with non cytotoxic concentration of MgO nanoparticles and incubated in 4˚C for 1hour and then added to cell culture. TCID50% (50% Tissue Culture Infectious Dose) of the virus as well as treated viruses was assayed by Reed and Munech method. Based on MTT assay، MgO nanoparticles had not any cytotoxic effect on cell culture in concentrations ≤ 250 µg/ ml. Treatment with MgO nanoparticles reduced the titers of viruses about 103. 5 (3162) fold compared to those of the controls. In conclusion، MgO nanopaticles have environmental antiviral effect on FMDV and could be used as disinfectant agent.

Strepococcosis and lactococcosis are economically important zoonotic diseases in aquaculture industry particularly in farmed rainbow trout. The annual loss due to the disease is tens millions USD. Because of the disease occurrence in farmed rainbow trout in Iran، this study was aimed to identify 20 risk factors in 38 trout farm in Fars (16 farms) and Lorestan (22 farms) provinces. Infected fish were sampled for the confirmation of the disease occurrence by bacteriological and molecular methods. The obtained results showed that there was a closed correlation between the presence of the risk factors (90%) and clinical signs (100%) of the disease. Also، bacteriological and molecular diagnosis methods، confirmed that the disease occurrence in 30 trout farms (15 fish farms in Lorestan and 15 fish farms in Fars) were involved in clinical farm of diseases. The results of this study also showed that the number of fish farms infected with Lactococcus garvieae was higher than Streptococcus iniae. Also، presence of both risk factors and clinical signs of the disease were significant in the trout farms of Fars and Lorestan provinces.

Lactoperoxidase is an enzyme of the oxidoreductase family. Lactoperoxidase is an important antimicrobial agent. Applications of lactoperoxidase are being found as a preservative in food and cosmetics. Immobilized LPO provides several significant benefits such as، easily separated from the reaction products، reducing production costs by efficient recycling and control of the process. Camel lactoperoxidase (LPO) was purified using CM sephadex C-50 ion-exchange chromatography، and sephadex G-100 gel filtration from camel milk. The activity of LPO was measured by using TMB (3، 3، 5، 5-tetramethylbenzidine) as a choromogenic substrate at pH6. 0. Purification degree was controlled with SDS-PAGE. The number of bacteria were found by spread plate technique and used 10 -6 dilution per ml for accomplishment of tests. According to statistical manner 3 test groups and one control group by four replications with equal conditions were formed for each bacterium. Test groups include 2 reagent groups (H2O2، tiocyanate) and one group containing H2O2 and tiocyanate together and one complete system {H2O2 (0. 03Mm)، tiocyanate (1Mm)، LPO (0. 02µg/ml)}. The numbers of bacteria were counted at 0، 60 and 360 mints by using spread plate technique. According to two-way variance analysis، significant results were shown between the effects of complete system and other for antibacterial activity (P<0. 0001). The results shown 46% reduced of colony form unit for Pseudomonas aeru ginosa and 100% reduced of colony form unit for Clostridium septicum after 360 Minutes. As a result، Lactoperoxidas enzyme was extracted from Camel Milk shown significantly anti-bacterial activity on Pseudomonas aeru ginosa and Clostridium septicum.

This study was undertaken to determine the influence nano oxide copper and mannan oligosaccharide supplementation on intestinal microflora and weight of internal body organs in broiler chicks. One hundred-sixty of Cobb-500 broiler chicks at 14 days of age were randomly assigned to four treatments. For each treatment، four replicates (10 chicks per replicate) were considered. Experiment was conducted as a factorial model in a completely randomized design. Experimental factors were: 0 and 100 mg/kg of copper levels and 0 and 1 g/kg mannan oligosaccharide. To measure of intestinal microflora from cloaca contents were sampled. Separation of internal body organs at the end of the experiment (42 day) was performed. Mannan oligosaccharide did not have any significant effect on the population of lactic acid producing bacteria and Enterobacteriaceae. Nano copper significantly reduced population of Enterobacteriaceae in cloaca (P<0. 05)، but do not show any significant effect on population of lactic acid producing bacteria. Weight of internal body organs، final body weight and abdominal fat were not affected by treatments (P>0. 05).