نشریه تازه ها در میکروب شناسی دامپزشکی
سال دوم شماره 1 (بهار و تابستان 1398)

Certain strains of extraintestinal pathogenic E. coli can cause urinary tract infection (UTI) in humans. Today, unnecessary consumption of antibiotics has led to resistance in bacterial populations. The aim of this study was to determine the tetracycline resistance genes and to evaluate the prevalence of antibiotic resistance among E. coli isolates collected from patients with UTI.In this descriptive cross-sectional study, 350 urine samples were collected from patients with UTI who were referred to the teaching hospital in Zabol during 6 months. E. coli was identified by conventional bacteriological test methods. Antibiotic susceptibility test was performed as recommended by the Clinical Laboratory Standards Institute (CLSI) using disk diffusion method. All tetracycline-resistant isolates were then examined for presence of the tetA, tetB and tetC genes.Of the 100 isolates of E. coli, the most antibiotic resistance was related to tetracycline (57%) and the least antibiotic resistance was related to ceftazidim (34%). Resistance to other antibiotics ceftriaxone, aztreonam and cefotaxime were 44%, 44% and 40%; respectively. Among tetracycline resistant isolates, 32 isolates (56.14%), had tetA gene and tetB and tetC genes were found in 28 (49.12%) and 6 (10.52%) isolates respectively. 16 (28.07%) and 3 (5.26%) isolates were positive for both genes (tetA and tetB) and three genes, and 14 (24.56%) isolates were negative for them.Resistance to tetracycline and other antibiotics, and the presence of tetA and tetB genes in UPEC strains are alarming signs in Sistan. The current study strongly recommends restricted consumption of antibiotics including tetracycline. Further studies are needed in other parts of the country to take more appropriate measures than common therapies.

Cryptosporidium is one of the most important diseases in livestock, poultry and humans; which is important both in terms of health and economics. It is caused by parasites of the genus Cryptosporidium, which is a parasitic apicomplexa protozoa. These protozoa can cause enteric infections, diarrhea, or respiratory infections. The present study aimed at determining infection with Cryptosporidium in native turkeys of Babol region. In the present study, 200 fecal samples from native turkeys were prepared and examined in 2016. Based on our results, from 200 examined samples, cryptosporidium infection was seen in 15% of the cases. There was no significant difference in infection rate between males and females. Pollution rates were higher in autumn than in other seasons. According to our results, native turkeys' cryptosporidium infection rate in Babol is high.  Therefore, more studies are needed in this field, and appropriate strategies for preventing and controlling this disease need to be presented.

The aim of this study was to determine the prevalence of liver contamination in broiler chickens slaughtered in Chaharmahal va Bakhtiari Province in two species of Campylobacter jejuni and Campylobacter coli and to investigate the virulence and antibiotic resistance of isolated strains. In this study, 186 liver samples from broiler chickens slaughtered in the slaughterhouses of the province were randomly collected. After the isolation of Campylobacter by microbial culture, for definitive confirmation of Campylobacter in isolated strains and definitive differentiation of Campylobacter jejuni and Campylobacter coli, the detection of 16SrRNA, mapA and ceuE genes was performed by PCR method. Antibiotic resistance pattern and distribution of virulence factors were evaluated. Of the 186 liver samples collected, 94 samples (50.53%) were infected with Campylobacter species, of which 62 cases were infected with Campylobacter jejuni (65.95%), 26 infected samples were Campylobacter coli (27.6% ) and 11 samples were contaminated with both species (6.45%). All virulence genes except the iam gene were present in Campylobacter jejuni isolates, and in Campylobacter coli strains only 5 cdtA, cdtB, cdtC, ima and racR genes were detected. All of the 88 isolates studied had multiple antibiotic resistance and in 26 isolates of Campylobacter coli, the highest antibiotic resistance was observed for streptomycin (96.15%) and the lowest was chloramphenicol (7.69%). In Campylobacter jejuni strains, the highest and lowest antibiotic resistance levels belonged to the two antibiotics ciprofloxacin (72.58%) and erythromycin (4.83%), respectively. High prevalence of Campylobacter jejuni and Campylobacter coli in broiler chickens slaughtered in Chaharmahal va Bakhtiari slaughterhouses and high antibiotic resistance of these isolates indicate a potential risk of liver contamination in human transmission.

Rabies is one of the most endemic zoonotic diseases which is very important due to its ability to be transmitted from animals to the mammals. The infected animal can transmit the disease to human beings or other animals through biting.  This is a retrospective study intended to survey the document of 6560 animal bites referred to the health center of Sari city during 5 years from 2012 to 2017, for factors such as age, sex, occupation, place of residence of selected individuals, type of the biting animal, time of bite and type of bitten organ were studied. Collected data was analyzed by Excel 2010 and SPSS 22 software, using descriptive and inferential statistics. P-value was considered < 0.05 for statistical significant. From a total of 6560 cases of animal bites, an average of 1093±87/52 animal bites happened annually in study area. Dogs, with a rate of 81.1%, were the most biting animals. Men with a rate of 77%, the age group of 20 to 29 with the average of 281.1 bites per year, self-employed individuals with 319.3 bites per year were the most referred cases. Rural areas with 64.3%, summer with 28.4% and the month of June with an average of 111.5 bites per year had the highest incidence of bites. Hands and feet were the most bitten body parts with 50.4% and 42.9% of bites, respectively. Special attention should be paid to eliminating the reservoirs of the disease, as well as increasing the awareness of the general population about the disease and its types of transmission.

Various factors affect viability of probiotic bacteria. In this investigation, the effect of some chemical specifications and the storage time on probiotic bacterial count in 30 samples of probiotic yogurts stored at 4ºC was studied. The samples were evaluated in 7 days interval for viable cell count, coli count, pH and acidity during refrigerated storage. The pour plate method of Culture with MRS-bile agar was used for enumeration of probiotic bacteria. Total coliform was enumerated in VRBA and BGB culture. Acidity of samples was determined with titration method and the values of pH were measured by a digital pH meter. The obtained results showed that the number of probiotic bacteria and titrable acidity in all of the samples were significantly decreased and increased, respectively. Also, the level of pH was decreased during the storage time. There were significant relationship between probiotic bacterial count and the amount of pH and acidity. A brief increase of probiotic bacterial counts was measured during the initial days, but there was sever declining during the final days of storage. 46.67% of examined samples had probiotic bacterial counts less than the minimum dose of 106 cfu per gram of yogurt in day 28. This study indicated that the deadline for storage and consumption of probiotic yogurts is 21 days after production. In addition, the decline in viability was dependent on the amount of pH and acidity.

This study aimed to investigate the parasitic infection in the apiary in Khash and Taftan border.  This research was carried out to adopt new management method, and design future studies in beekeeping industry in Sistan-Baluchistan Province. Samples were taken from 30 apiaries and 375 honey bee colonies, in autumn, winter, and spring (autumn and winter 2015 and spring 2016). The results showed that the infections rate with Varroa was 80%, 86/6%, 80% in autumn, winter and spring; respectively. The highest infection rate in the study area was recorded in winter with 86/6%. Also, the infections rate with Nosema was 0%, 80%, 46/6% in autumn, winter and spring; respectively. Both diseases are major parasitic infections, causing annual damage to beekeepers. Also, statistical analysis using SPSS software showed that the purchase of pollen, wax and equipment from other farms, as well as non-use of protective wall, lack of migration in the winter and the lack of prevention and treatment, increases the infection rate with the parasites. The results of chi-square and Fisher's exact test revealed significant relationship between these variables and parasites infection (p <0.01).

This study aimed to evaluate the antibacterial and antifungal activity of various extracts of the Rhazya stricta, Capparis spinosa, cretica Cressa. Rhazya stricta, Capparis spinosa, cretica Cressa plant collected from Saravan city, Sistan and Balouchestan Province. Extraction with different solvents was performed with a rotary machine. Standard bacteria were purchased from Persian Type Culture Collection (PTCC). Minimum inhibitory concentration and minimum bactericidal concentration were determined by the micro-dilution method. The results of this study showed that the lowest inhibitory concentration of the aqueous extract against E. coli, Bacillus cereus, and Shigella dysenteriae was 2.5 mg/ml. The results of this study also showed that the lowest inhibitory concentration was related to methanolic extracts of Cressa, which is equal to 0.62 mg/ml and Bacillus cereus bacterium is inhibited in this concentration. The lowest inhibitory concentration of the Caper extract (0.62 mg/ml) that inhibited Escherichia coli and Bacillus cereus, belonged to ethanolic extract. Also in the same concentration, the hydroalcoholic and methanolic extracts inhibited Shigella disneraceae and Pseudomonas aeruginosa. The results of this study indicate that the extract of the Cressa and Caper herb has good antimicrobial effects on fungal and bacteria pathogenesis.

Koozehee Cheese is a cheese with a semi-hard and creamy color that is rich in fat and spicy flavors and is produced traditionally in west and north-west of Iran. The aim of this study was to evaluate the chemical and microbial characteristics in Koozeh Cheese samples of Kurdistan Province. A total of 84 samples of traditional Koozehee Cheese were collected from the Saqez, Baneh and Sanandaj Cities, randomly in winter. Chemical tests included dry matter, acidity, pH, fat, protein, ash, salt, calcium and phosphorus measurement, and microbial tests included coliform counting and yeast and mold counting, and identification of E. coli, S. aureus, Salmonella and L. monocytogenes in Koozeh Cheese samples. Mean of dry matter was 57.25%, pH was 5.59, acidity was 83.69 Dornic degrees, protein level was 43.01%, fat level was 22.52%, ash level was 10.58%, salt level was 6.79%, calcium level was 1.02 g/100g and phosphorus level was 0.67 g/100g. Contamination of Salmonella and L. monocytogenes were not observed in any of the samples, and the infection with coliform was 45.2%, E. coli was 31.0%, yeast and mold was 23.8%, and S. aureus was 11.9%. Koozeh cheese of Kurdistan province is rich in protein, calcium and phosphorus sources, and has a high nutritional value. But it is unaccepted for microbial characteristics (S. aureus, coliform, E. coli, yeast and mold) and its production and supply process requires a health monitoring. The industrial production of Koozeh Cheese can improve its health; also, it can lead to expansion of the supply of this beneficial product in Iran and the other countries.

Brucellosis is an important zoonotic disease which threatens public health and livestock industry. The aim of this study was to optimize extraction of rough lipopolysaccharide from Brucella abortus which can be used as the antigen for the development of serological tests to diagnose vaccinated animals. This applied study was performed in the Brucellosis Research and Production Laboratory. For this purpose, the rough strain was cultured in Brucella agar specific medium and final diagnosis was performed by PCR method. The rough lipopolysaccharide of Brucella abortus was extracted by phenol-chloroform-petroleum ether method and the results of rough LPS extraction were approved by LAL and SDS - PAGE methods. Extraction and precipitation of Lipopolysaccharide with cold methanol and sodium acetate was performed by using Phenol – Chloroform - Petroleum ether method. Then Lipopolysaccharide was identified by Limulus Amebocyte Lysate (LAL) test and formation of clots indicated presence of Lipopolysaccharide.  Also SDS – PAGE (14 % Polyacrylamide gel) followed by silver nitrate staining showed a 12 KDa band which indicates Rough Lipopolysaccharide. According to the results of this study, it seems that Phenol – Chloroform - Petroleum ether method is an excellent method for extraction of rough LPS of antigen for the development of serological tests and ELISA Kit to diagnose vaccinated animals.

The process of antibiotic resistance is divided into two categories: intrinsic and acquired resistance. In intrinsic resistance, the bacteria show resistance due to their specific properties to one or all of the antibiotics. But acquired resistance is caused by molecular changes in susceptible bacteria and, eventually, it causes antibiotic-resistant bacteria to emerge. That could be due to chromosomal mutations, transposons, or transmissible plasmids. Numerous genes control the different mechanisms of bacterial resistance to antibiotics. The tetA and tetB genes are the major activating genes for tetracycline efflux mechanism, which decrease the concentration of tetracycline in bacterium. This study was performed to reconstruct the network of tetA and tetB genes using data and information in molecular databases. The reconstructed network clearly confirms that tetA and tetB genes have a direct role in tetracycline efflux. In association with other proteins, tetB, in addition to tetracycline efflux, plays a key role in the detoxification and antiport of a wide range of toxins, such as streptocycline and phenolic acids. Gene Anthology analysis showed that most of the genes involved in the tetracycline resistance process are membrane proteins and their molecular function is transporter.

Beef contamination usually occurs in the killing process. One of the intestinal bacterial pathogen that causes disease in human and animals everywhere is bacterial pathogen E. coli. One of the important serotypes of this bacterium is E. coli O157: H7. The aim of this study was to determine the rate of contamination of beef produced in Zahedan to E. coli by MPN Method and also O157:H7 strains isolated by PCR. During this study, conducted within six months from July 1396 to July 1397, 360 beef samples from cattle meat packages of Zahedan City, from different parts of the carcasses isolates of the heat-resistant E. coli in the laboratory was carried out using the MPN method. Seventy isolates were finally detected. The final test was performed using a specific primer as rfb to detect E. coli O157:H7 using a PCR reaction. Only one isolate was confirmed based on this serotype, which indicates the proper health status of the meat produced in Zahedan. In the present study, a molecular study of 2 isolates of heat-resistant Escherichia coli bacteria was done. In the study of rfb gene, only one isolate in terms of Escherichia coli serotype 7H: 157O was confirmed. With this study, the presence of this bacterium in beef samples is confirmed, which can indicate that the presence of this bacterium in other raw animal products in this province should also be investigated and tracked.

The importance of food-borne disease and consumer demands for avoiding synthetic food preservatives shifted the research interest to natural food preservatives such as essential oils isolated from medicinal plants which have antimicrobial activity. The aim of this study was to evaluate the efficiency of Achillea millefolium essential oil as natural food preservative against foodborn pathogens such as Staphylococcus aureus, Escherichia coli, and Salmonella enteritidis which were inoculated into high fat mayonnaise (65%) and low fat mayonnaise (30%) and kept during storage at 4 oC for 6 months. The results showed that essential oils of Achillea millefolium had influence against all of the tested microorganisms in vitro, while Gram-positive bacteria was more sensitive to essential oil than Gram-negative bacteria. All of the pathogens did not grow in mayonnaise, whereas in the control sample, all of the microorganisms grew. The maximum cell counts of bacteria in low fat mayonnaise were approximately lower than the high fat mayonnaise and resistance to inactivation of microorganisms appeared to be greater in high fat mayonnaise than in low fat mayonnaise. Also low fat and high fat mayonnaise in BS samples exhibited antimicrobial properties against tested species during storage. By way of conclusion, the essential oil of Achillea millefolium would lead to control food pathogen organisms as a natural food preservative and therefore, it can be used as natural preservative in food industry.