نشریه میکروبیولوژی دامپزشکی
سال هجدهم شماره 2 (پیاپی 45، پاییز و زمستان 1401)

Shrimp diseases are one of the major limitations for increasing shrimp production, and the cause of white spot disease is the most important pathogenic virus in shrimps, which causes irreparable damage to the shrimp farming industry. Therefore, the purpose of the present study was to trace the white spot virus in wild sources at the Boyrat shrimp breeding site in Bushehr province. The present study was performed in Boyrat shrimp breeding complex of Bushehr province by sampling of wild resources. DNA was extracted from 20 samples of wild resources collected included: three samples of Metapenaeus ensis, one sample of Saurida tumbil, one sample of Terapon puta, ten samples of mud crab, two samples of blue crab and two samples of Litopenaus vannamei post larvae during preparation, grow out and harvesting from ponds and white spot virus was detected with PCR test. The results obtained in the present study indicated that the most positive cases are related to grow out stage (83.3 %) and harvesting stage (28.6 %) and in the preparation phase, the frequency of the disease was 0%. In total, 35% of cases (Metapenaeus ensis, small blue crab and small mud crab) were infected with white spot disease in all cases. The highest frequency of infection with the mentioned virus was in Metapenaeus ensis (100 %), small blue crab (100 %), and small mud crab (33.3 %), respectively. In total, among all studied species, 25% infection with white spot disease was observed. According to the results obtained in the present study, in order to prevent pollution in shrimp ponds, it is recommended to use different management methods to prevent wild sources from entering the ponds.

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.

Leptospirosis is a common zoonotic infectious disease, that cause by pathogenic Leptospires. FlaB2 is a periplasmic flagellum protein that is expressed during infection in the host. This protein is conserved among all pathogenic Leptospiral serovars. The aims of this study was molecular evalution of the gene encoding FlaB2 protein by PCR method in pathogenic Leptospira serovars in Iran. In this study, 20 pathogenic Leptospira serovars and two nonpathogenic Leptospira serovars were used. All 22 Leptospira serovars were cultured into the selective medium EMJH and genomic DNA was purified using standard phenol-chloroform method. Specific primers were designed for amplification of flaB2 gene and its sensitivity and specificity were evaluated by PCR. The results of PCR product of flaB2 gene was 1050 bp and it was observed that all 20 pathogenic leptospira serovars contained the flaB2 gene. This gene was not amplified from two non-pathogenic L. biflexa. The results of this study showed that the gene flaB2 gene was present only in pathogenic serovars. Therefore, molecular characterization of flaB2 gene is important for detection of pathogenic serovars from nonpathogenic Leptospira serovars

Dermatophytosis are a type of fungus that commonly causes skin lesions. Dermatophytosis injuries can be painful for both animals and their owners. Dermatophite agents are anthropopilic, zeopilic and geopilic. In this study ,the prevalence of this disease in dogs in Babolsar was studied . For this aim, 100 dogs referred to city clinics were sampled over the course of six months, and the rate of infection with dermatophyte causes was determined to be 13% after culture and microscopic observation. Microsporum canis was the most common cause of dermatophyte infection, accounting for 61 percent of all infections, which was significantly (P<0.05) higher than other dermatophytosis pathogens. Microsporum gypseum, Microsporum nanum, and Trichophyton verrucosum were among the other isolates. In addition, the rate of infection in dogs above the age of one year was significantly increased (P<0.05), however there was no significant difference in infection between the genders. Finally, while the amount of infection in Babolsar was lower than in past research investigating at the prevalence of dermatophyte causes, it is nevertheless suggested that people of all ages conduct better hygiene and animal care.

In order to determine the sero-epidemiological prevalence of Neospora caninum in Garmsar, in this study, bulk milk samples were prepared for ELISA testing from 72 large herds of dairy cows in Garmsar city (about 10% of all livestock farms in this city). Also, serum samples of 11 dog belonging to herds with positive blood samples were taken and sent to the laboratory to be analyzed by ELISA kit. The findings showed that in 55 farms (75.4%) the results of the ELISA test were positive. In 11 samples taken from herd dogs, positive results were shown in 9 dogs. The geographical region of sampling, livestock population in the herds, parturition to pregnancy interval, pregnancy and the conception did not differ between ELIZA positive and negative herds. (P>0.05). The average number of female calves in the negative ELISA herds was 2 and in positive ELISA was 3 (P=0.01). The mean rate of herd pregnancy in positive ELISA herds was 50% and in negative ELISA herds was 45% (P>0.05). Also, the average milk production per cow was 27.8 kg in negative herds and 26.9 kg in positive herds (P=0.026). The correlation between the presence of dogs and the spread of this parasite was confirmed by Pearson's and Spermman's correlation tests. (P=0.00, r=0.47). It was concluded that in Garmsar city, 75.4% of the bulk milk of the examined herds had a positive ELISA result, and the amount of milk production in these positive herds was less and the presence of dogs was more.

Parasitic diseases in natural and cultured fish systems have always brought many problems to farm owners. One of the most common parasitic diseases in fish is eye parasite infection Diplostomum spathaceum in natural resources and breeding farms. This parasite is digenean parasite that has a complex life cycle and distributed in fresh-water fish around the world. The infectious and pathogenic form of this parasite causes cataract by infecting the eye of fish, which cause many problems for fish after the disease occur. In this investigation, the infection with the parasite Diplostomum spathaceum in 60 samples of fish caught from Bukan Dam in the west Azarbijan province from spring to winter of 1400 was studied. The results showed that 43.3% of the fish (26) were infected with this parasite, which indicates that the fish in this water source are highly infected. The average intensity of infection in fish was 9.47±1.56 and the number of parasite metacercaria in the eyes of fish was between 1-14. Statistically, a significant relationship was observed between the severity of D.spathaceumcontamination in different seasons of the year (p<0.05) and the comparison of seasons showed that the highest contamination rate was 73.3% in summer and the lowest was 3.3% in winter.

Identifying new antimicrobial compounds is a way to deal with spread of bacterial resistance, which bacterial pigments are one of the antimicrobial compounds. The most common causes of treatment-resistant infections in humans and animals are bacteria such as Pseudomonas aeruginosa and Acinetobacter. The purpose of this research is to compare the antibacterial properties of prodigiosin pigment from Serratia marcescens and carotenoid pigment from Rhodotroella glutinis on Pseudomonas aeruginosa and Acinetobacter. After separating the bacteria and identifying them, by using differential tests, Serratia marcescens (PTCC: 1111) and Rhodotrola (PTCC: 5256) pigments were extracted through chromatography. In order to evaluate the effect of different dilutions of pigments on bacteria, sterile 96-well microplates were used and the minimum inhibitory concentration (MIC) and minimum lethal concentration (MBC) were determined by broth microdilution method. Welling was done with different volumes of pigments. Out of the 50 burn wound samples, 26 samples were positive for the presence of two bacteria, all of which were sensitive to colistin and resistant to gentamicin, imipenem, ceftazidime, amikacin and ciprofloxacin. After the effect of both pigments on Pseudomonas aeruginosa, the highest MBC observed was 25 microliters, and after the effect of prodigiosin pigment on Acinetobacter bacteria, the highest MBC was 6.25 microliters, and this value for carotenoid pigment was 25 microliters. In welling, the largest average diameter of the zone of inhibition related to two pigments against these bacteria was observed in the volume of 200 microliters

Aflatoxins are natural toxins that contaminate various types of food in humans and animals and pose a threat to their health. The aim of this study was to investigate the presence of aflatoxin B1 in dry cat and dog food offered in Isfahan province by ELISA method. The samples used in this study included 96 samples including 48 dog food samples from 12 commercially brands and 48 samples from 12 cat food brands that were collected by referring to pet shops in Isfahan. 200 g of sample was taken from each brand and transferred to the laboratory. It was then thoroughly ground in a mixer and tested according to the manufacturer's AFB1 Commercial Ready Kit. The results of the present study showed that the presence of aflatoxin B1 with a concentration range of 24 to 38 ng/g was detectable in the all samples. In addition, all brands showed higher levels of aflatoxin than normal level (20 ng/g). Among the studied dog food brands, no significant difference was observed between foreign and domestic brands, but in the comparison of aflatoxin levels of foreign and domestic brands of cats, the amount of this mycotoxin was higher in domestic brands. Since this mycotoxin affects the health of animals and causes serious disorders in these animals, and considering that in all brands studied in this study, aflatoxin level was higher than the allowable limit. Continuous monitoring of Aflatoxin B1 by dog and cat food industries as well as control of feed imports is essential.

Embryonic mortality in ostriches can reduce the income of the ostrich production industry. Many factors play role in reduce hatching such as infectious agents. Among infectious agents, the role of Klebsiella in fetal losses, especially in ostriches, has been less studied. Therefore, in the recent research, 200 swab samples from dead ostrich embryos were collected and Klebsiella infection was identified with microbiological and biochemical methods. Then, Klebsiella species and virulence gene of magA were identified and determined by PCR method with specific primers. The results showed that out of 200 ostrich egg samples, 60 eggs infected with Gram-negative bacteria (30%) and 20 eggs were infected with Klebsiella (33%). Out of 20 Klebsiella strains, 15 and 5 strain identified as K. pneumonia (75%) and K. oxytoca (25%), respectively. None of the Klebsiella strains carried the magA gene. In this study, Klebsiella strains showed the highest sensitivity to imipenem (100%) and the highest resistance to enrofloxacin (70%). In general, Klebsiella spp seems to have 10% share in ostrich embryonic mortality, so preventing surface contamination and observing the principles of disinfection in ostrich hatchery play role in reducing embryonic mortality due to surface contamination.