نشریه میکروبیولوژی دامپزشکی
سال هشتم شماره 1 (پیاپی 24، بهار و تابستان 1391)

The possible bacterial infections were studied in six farmed rainbow trout in Mazandaran province at Haraz river region during spring, summer and autumn 2008. The external and internal clinical signs of affected fish were recorded and a number of 20 diseased fish from each fish farm were then obtained for bacteriology studies during each season. Clinically, the affected fish were lethargic showing blindness or exophthalmia, darkening of body, abdominal distension and prolaps of anal area. Internally, signs of hemorrhage in the intestine, pale and tattoo liver and accumulation of bloody fluids in the abdominal cavity were observable in dissection. From total 360 fish samples processed for routine bacteriological works, 149 samples were positive for Gram positive bacteria consisting of Streptococcus iniae (51 isolates), Lactococcus garviae (7 isolates), Staphylococcus areus and S. epidermidis (91 isolates). Also, 39 fish samples were positive for Gram negative bacteria consisting of Aeromonas hydrophila (20 isolates), Yersinia ruckeri (14 isolates) and Vibrio anguillarum (5 isolates). In antibiogram, all bacterial isolates were sensitive to enrofloxacine and flumequine while showing a variable sensitivity to peniciline and erythromycin. Total incidence of affected fish in the investigated fish farms to these bacterial infections were 52.22% and the highest incidence of infections were due to stapylococcosis (5.27%) and streptococcosis/lactococcosis (16.10%). Furthermore, the seasonal incidence of these bacterial infections during spring, summer and autumn were 40.83%, 6.66% and 49.61%, respectively. The results of this study show that the farmed rainbow trout of Haraz region are affected with different bacterial infections.

Nowadays, multiple drug resistance and side effects such as residual drug, hypersensitivity, immune-suppression and allergic reaction has developed among humane society and animal due to the irregular use of commercial antimicrobial drugs. Therefore, use of natural compounds such as medicinal herbs for therapeutic goals is recommended. In the present study, an attempt has been made to investigate the antibacterial characteristics of Nigella sativa against ten different wild veterinary bacterial pathogens. Identification of clinical isolates from different bacteria was done on the basis of morphology, cultural characteristics and biochemical reactions. MIC and MBC were determined by macro broth dilution method using serially two folds diluted of ethanol extracts from Nigella sativa. The main bactericidal and bacteriostatic activity of ethanol extract of Nigella sativa against pathogenic bacteria were respectively as MBC (mg/ml) and MIC (mg/ml) Yersinia enterocolitica (200-100), Listeria monocytogenes (25-12.5), Corynebacterium pseudotuberculosis (12.5-12.5), C. renale (6.25-3.125), Brucella abortus (50-25), Pasteurella multocida (6.25-6.25), Mannheimia haemolytica (3.125-3.125), Escherichia coli (200-100), Trueperella (Arcanobacterium) pyogenes (6.25-3.125), Staphylococcus aureus (50-50). The highest antibacterial activity was shown against M. haemolytica with the MIC of 3.125 mg/ml and the least for E. coli and Yersinia enterocolitica with the MIC of 100 mg/ml. The result of this study showed that ethanol extract of Nigella sativa exhibited an inhibition in the growth of all examined pathogenic bacteria and this extract or the compounds derived from it can be used in control of infectious agent.

Blue tongue disease is a non-contagious, viral disease of ruminants, mainly sheep and less frequently cattle, goats, buffalo, deer, dromedaries and antelope. That is mainly transmitted by insects and cause lesion in the mouth, nasal mucosa, and limb, also existing reports of create abortion in some animals. Camel might be reservoir of BTV without showing of any clinical sings so it can be spread the virus among other regions and animals. The objective of this study was genomic detection of bluetongue virus in one humped camels slaughtered in central part of Iran. In order to detection of S7 sequence of bluetongue virus genome in 110 one humped camels that slaughtered in Najafabad abattoir, specimens were prepared. For preservation of coagulation heparin was added to blood samples and they transported to laboratory in cool box. RNA was extracted by acid guanidinium-isothiocyanat and phenol chloroform method and they were detected by reverse transcriptase polymerase chain reaction (RT-PCR). All PCR products were separated by 1.5% agarose gels electrophoresis and stained with ethidium bromide. After that, they were analyzed by using gel documentation. The results of tests showed that all of samples were negative. Fortunately, it shows that in this studied area in our country, this infectious cannot be exist or transient infection in camel does not persist for a long time. As BTV infection was reported in some provinces, we highly recommend to expand study on camel infection with BTV.

Chlamydophila is an organism similar to geram negative and interacellular bacteria that is classified in Chlamydiacae family. Various types of Chlamydophila exist in this family that can infect their hosts. The species that infects birds is Chlamydophila psittaci. It can cause diseases in humans. The disease is transmitted via touching or secretions and the infected objects of infected birds, especially psittacine birds. The purpose of this research is the Molecular detection of Chlamydophila psittaci among dead and suspected cases of psittacine birds in Tehran. In this study, 23 excrement swabs of suspicious parrots and 7 cloacal swabs of dead but suspicious to the existence of Chlamydophila were investigated. The samples were kept in -20 C degrees up to the extraction time. The method of DNA extraction was performed by Celica filters, and then was examined by using Nested PCR Method based on 16SrRNA genom of chlamydophila. The findings obtained from 10 positive cases among 30 tested samples. The results showed the importance of giving more information to the psittacine birds’ keepers about Chlamydophila in order to have healthy parrots and to prevent their keepers from the disease.

Hematologic changes and serum biochemical analysis of 20 naturally infected and 15 non-infected calves with theileria annulata were carried out. Theileriosis was confirmed by observing theileria merosoites in red blood cells of peripheral blood smears of calves. Two blood samples were taken from the jugular vein in disposable polyethylene tubes one with anticoagulant (EDTA) for hematology and another 10 ml without anticoagulant substance for biochemical analysis. Compare the results the patient and control groups performed with Spss software and "t" test in the P<0.05. The results of this study showed that hematocrit, hemoglobin, red blood cells (RBC) count, platelets count and serum total protein were significantly reduced in calves infected with theileria (infected calves) compared with healthy calves (control group). Calcium, magnesium and glucose concentrations were also decreased in infected calves, but this was significant only in calcium. Phosphorus concentration had increased but this was not significant statistically. The results of present study shows that theileriosis in calves causes significant decrease in serum calcium which as new finding special attention should be paid when treating animals in addition to the disease specific treatment.

Escherichia coli O157:H7 is now recognized as an important cause of diarrhea, hemorrhagia colitis and hemolytic-uremic syndrome worldwide. Meat contaminated with animal feces is probably the major source of the E. coli O157:H7. In this study, we investigated the prevalence of E. coli O157:H7 in meat samples of bovine in Rafsanjan, Iran. This was a descriptive - analytical and descriptive study, which was conducted from April 2011 to February 2012. A total of 148 bovine carcasses were sampled by surface section of neck meat taken immediately after slaughter analyzed using microbiological examinations. Suspected colonies to E. coli O157:H7 were confirmed by a specific polymerase chain reaction method (PCR). The results showed that the contamination rate of samples to E. coli and E. coli O157:H7 were 36(24/32%) and 10(6/75%), respectively, six samples (4/05%) were identified as E. coli O157:H7, using polymerase chain reaction. Seasonal distribution showed that the highest prevalence of E. coli and E. coli O157:H7 occurred in summer samples (P<0.05).These results indicate that bovine can be a reservoir for E. coli O157:H7 and bovine meat may serve as a vehicle for the pathogen transmission to human.

Antibiotic resistance in Staphylococcus aureus strains against beta-lactam antibiotics have specified. Because of drug resistance the treatment of staphylococcal mastitis is difficult and resistance transmission to human is possible. Use of modern technology for treatment is necessary and the therapeutic properties of silver nanoparticles have already been proven. In the present study, 311 milk samples were collected from mastitis casase in cattle. California mastitis test (CMT) used for detection of mastitis cases and bacteriological cultures carried out on all milk samples in order to identify the S. aureus. In addition to accurate identification of S. aureus, nuc gene was amplified by PCR. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of silver nanoparticles and antibiotics individually and in combination were determined on 50 S. aureus as isolates. Patterns of S. aureus isolates resistance to penicillin, amoxicillin, ampicillin and cefazolin, were 50%, 56%, 46% and 30% respectively. 8% of all isolates were sensitive to low levels of silver nanoparticles. Based on this study, silver nanoparticles in combination with beta-lactam antibiotics have more effect on S. aureus isolates than any of the antibiotics or silver nanoparticles alone.

The peripheral blood of an injured Common Buzzard (Buteo buteo), which was kept in East Azerbaijan Environment Organization, was collected in August 2011. The blood sample was taken from the brachial vein and transferred to the Laboratory of Parasitology, School of Specialized Sciences of Veterinary Medicine, Science and Research Branch, Islamic Azad University in Tehran. Having stained the blood smears with 5 % buffered Giemsa stain; they were carefully examined under a light microscope with X1000 magnification. It was observed that the bird erythrocytes harbored Leucocytozoon sp. This is a first report of an eagle owl infection with Leucocytozoon sp. in East-Azerbaijan province of Iran.