محسن نجیمی

Brucellosis or malt fever (Mediterranean fever) occurs due to the growth and multiplication of the gram-negative coccobacillus Brucella in mammalian cells, and this disease is important as a common disease between humans and animals. Several serological tests have been investigated to identify this bacterium, however, these methods have limitations in the accurate identification of the bacterium. The present study was conducted with the aim of investigating and molecular identification of Brucella bacteria in samples collected from infected sheep in Sistan region using multiplex PCR technique. At first, blood and milk samples were collected from infected sheep. Confirmation of bacterial infection was initially done using blood samples and Rose Bengal serology method. Next, DNA was extracted from the collected milk and molecular analysis was performed using multiplex PCR and amplification of Omp31 and BLS genes, in order to amplify fragments with sizes of 347 bp and 256 bp respectively. Out of the 40 clinical samples, all of them showed a positive Rose Bengal test, but molecular analysis using multiplex PCR showed 5 false positive samples confirmed with the Rose Bengal test. Due to the higher sensitivity and accuracy and short time of identification the molecular methods can be used as a suitable option for identifying pathogens.

Subclinical mastitis is one of the common problems of dairy farms, which leads to a decrease in production and economic damage to the farmers. Identification of the pathogens causing subclinical mastitis in each region is necessary to prevent and control this problem. The aim of this study was to investigate the molecular prevalence of Staphylococcus aureus bacteria in subclinical mastitis cows in dairy farms of Neyshabur city. A total of 500 milking cows from 13 dairy farms located in different parts of Neyshabur city were included in the study. Milk samples were taken from all quarters and checked for subclinical mastitis using the California mastitis test. Milk samples were taken from the quarters that were positive in the California mastitis test, and evaluated for contamination with Staphylococcus aureus using polymerase chain reaction. Out of 500 dairy cows studied (2000 quarters), 94 (18.8%) had subclinical mastitis, and Staphylococcus aureus infection was detected in 8 cows (8 quarter). Based on the results of this study, the occurrence rate of subclinical mastitis as well as the prevalence of Staphylococcus aureus among subclinical mastitis cows in dairy farms of Neyshabur city is low.

Antibiotics have long been the first line of defense against Escherichia coli infection, but they have lost their potency as the bacteria become increasingly resistant to treatment. The aim of this study was to evaluate the resistance to tetracyclines and the prevalence of tetA and integron class I resistance genes in E. coli isolated from broilers with colibacillosis. In this study, 96.6 % of Escherichia coli isolates resistant to one or both tetracycline antibiotics were studied. Experimental results showed that 98.2 % of tetracycline-resistant Escherichia coli bacteria isolated from lesions of colibacillosis carry tetA. The prevalence of class I integron gene was 98.2%. Also, 96.5% of the isolates of this bacterium carried both genes. Considering the results, the prevalence of tetA and integron class 1 genes in this study was significantly higher than other studies. This difference could indicate high antibiotic resistance in poultry farms in this region which emphasizes the need for cautious use of tetracyclines in poultry production to reduce the prevalence of E. coli resistant to these antibiotics.

The most economically significant bacterial pneumonias are pasteurellosis and mycoplasmosis as causative agents of reduction in production, weight loss, increasing mortality rates in dairy and fattening sheep herds. This study was conducted to determine the histopathological and molecular properties of lung lesions caused by pasteurellosis and mycoplasmosis in slaughtered sheep at Fariman. A total of 4960 lungs were collected from sheep slaughtered at Fariman abattoir in 2019-2020. 90 of 4960 (1.81%) lungs which were macroscopically suspected to be suffering from pneumonia were examined microscopically. The polymerase chain reaction test was carried out for molecular detection of Pasteurella multocida and Mycoplasma ovipneumonia. Furthermore, statistical analysis was performed using the Chi-square test and the data were analyzed by SPSS software version 20. The molecular analysis showed that 16 specimens (0.032%) were positive for P. multocida, but M. ovipneumonia was negative in all specimens. In the histopathological investigation, the most common lesion was suppurative bronchopneumonia (1.16%). In addition, there was no significant association between age, sex and season with P. multocida (P˃0.05). These findings revealed that P. multocida is one of the common cause of bacterial pneumonia in slaughtered sheep at Fariman and its histopathological characteristics are notable.

Blue Open Reading (bor) and increased serum survival (iss) genes, with intense structural and possible functional similarities, engage in the serum resistance of Avian Pathogenic Escherichia coli O78 (APEC-O78).

This research aimed to determine whether there is a correlation between the transcriptional level of bor and iss of APEC-O78 inoculated in serum.

Total RNA was extracted 24, 28, and 32 hrs after the inoculation of an APEC-O78 isolate, χ1378, to chicken serum. The fluorescence intensities related to the bands of gel electrophoresis of bor and iss were computed after cDNA synthesis and reverse transcription -PCR reaction assay. Using Pearson’s partial correlation tests, the relationship between the transcriptional levels of bor and iss, and the influence of the selected time points on the possible relationship were respectively measured at P<0.05 for statistical significance.

A correlation was observed between the transcription levels of bor and iss (P=.012), which was not influenced by the selected time points (P=.001).

The bor must be carefully weighed in the transcriptional analysis including iss and vice versa. The number of transcripts/alleles, upstream sequence, regulation process at the pre-transcriptional phase, and the location of bor and iss in χ1378, and taking samples from different time intervals may explain our result. Our find-ings emphasizes the multifactorial and complex mechanism of APEC-O78 serum resistance, and can lay the foundation for further studies on the transcription of bor and iss, particularly in the specific strain and the three time points.

Brucellosis is the most important zoonotic diseases among the various strains of Brucellabacteria, Brucella melitensiswith sheep's tank, is the most acute and the most common Brucellosis agent in humans that also creating abortions and reduction milk production in sheep, causes problems in animal husbandry. Prevention of the disease with identification and control of the disease reservoir is the most important priority of health organizations in order to eradicate brucellosis. In this study, we assessed identification Brucella melitensisin aborted fetal sheep in Gonbad-e Qabus Country.

The contents of the samples of 57 of aborted fetuses of sheep were sampled then DNA extraction was performed using a gene extraction commercial kitand in order to detect Brucella melitensis, the samples were tested by PCR.

Result of PCR was showed of the 57 samples taken in Gonbad-e Qabus County, 10 cases (17.5%) contained Brucella melitensis.

Considering the identification of positive cases of brucellosis in sheep inGonbad-e Qabus County,in order to prevent and eradicate the disease, presenting training classes for livestock breeders, vaccination and removal of positive cases at the level of total livestock in the County is necessary

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.

Vibrio fluvialis causes disease and significant economic losses in breeding fish. This bacterium is considered as a human pathogen and several species of marine spawning fish. The egg yolk immunoglobulin technology (IgY) has been used to control many microbial infections. The purpose of the present study was to evaluate the vaccine prepared from V. fluivialis bacteria after injection into laying hens. V. fluvialis was admixed by 0.05% formaldehyde after culture in a liquid medium. Then, the pathogen along with Freund’s adjuvant was injected to the Hyline W36 hens as a vaccine for 7 days. Increase of the weight of the hens was measured until Physical maturity and egg production. Then, an Indirect ELISA was designed to detect IgG Anti V. fluivialis. Injection of the vaccine had no significant effect on weight gain of hens and the number and weight of eggs during the experiment. ELISA test showed that antibody titers in the serum of hyper-immunized hens after injection of the fourth booster reached 1: 12800. According to the results obtained and the results of studies by other researchers, egg yolk antibody (IgY), which is the same as IgG, has been shown to inhibit the pathogenicity in lab and farm animals.

Abortion in sheep and goats causes enormous economic losses. This study revealed the epidemiology of abortion caused by Brucella melitensis, Coxiella burnetii and Salmonella abortusovis in Baluchi sheep in Sistan region. In the autumn of 2015 and winter of 2016, a total of 78 aborted sheep fetuses were collected from all over the Sistan region. Risk factors, including location of livestock, history of abortion, gender of fetus, age of fetus, age of ewe and parity were obtained using a questionnaire. The results showed that 27 fetuses (35%) were infected with these organisms. Infection with B. melitensis, C. burnetii and S. abortusovis were identified respectively in 15 (19.2%), 13 (16.6%) and 1 (1.3%) fetus. Logistic regression analysis showed that infection with B. melitensis in male fetuses is higher than females (OR=3.73, P=0.040), also infection with C. burnetii in ≤2 years’ ewes (OR=0.047, P=0.009) and 2-5 years’ ewes (OR=0.197, P=0.069) is lower than ≥5 years’ ewes.

Campylobacter is one of the main bacterial causes of ewe abortion throughout the world. Campylobacter infections are now considered as zoonoses. The objective of this study was an investigation of Campylobacter fetus prevalence among aborted ovine fetuses in the Sistan region (north of Sistan and Baluchestan province). In the present study, spleen and abomasum content samples were obtained from 78 aborted lambs of Baluchi sheep. The samples were examined for campylobacter contamination using PCR method. The overall prevalence of campylobacter infection was 7.7%. The prevalence of infection in fetuses aged three months and under were significantly higher than that in fetuses older than three months. The result of this study showed that C. fetus should be considered as one of the infectious causes of abortion among sheep flocks in Sistan region.

Klebsiella pneumoniae that causes bloodstream and urinary tract infections has several virulence factors encoding genes. Factors like the ability of adherence to the host cell surface, presence of sidrophore receptors and regulation of mucoid phenotype are the common virulence ones involved in the pathogenesis of K. pneumoniae. The aim of this study was to determine the frequency of virulence factor encoding genes in K. pneumoniae isolates, collected from hospitalized patients by Multiplex PCR.
In this descriptive study, the frequency of genes encoding virulence factor irp2, wcaG, rmpA, rmpA¡ allS and fimH were evaluated in 100 K. pneumoniae isolates, collected from patients referred to teaching hospitals of Zahedan city by Multiplex PCR.
Among 100 clinical isolates of K. pneumoniae, allS gene had the highest frequency, 90%, and rmpA had the lowest frequency, 6%. The frequency of genes fimH, irp2, wcaG and rmpA were 88%, 87%, 33% and 6% respectively.
The results of this study showed that the allS, irp2 and fimH genes were more frequent among K. pneumoniae isolated from studied patients in Zahedan city. These findings provide important information on the importance of these virulence factors on pathology of urogenital tract infection, management of Klebsiella infection and success of treatment strategies.

Progress of drug resistance in nosocomial gram negative bacteria is a serious threat to the health of patients, personnel of treatment sections and to public hygiene in total. Identifying and using novel antibacterial compounds such as thiazole, imidazole and tetrahydropyridine derivatives as well as silver nanoparticles could be a significant solution to this issue. In this regard, we accomplished the study and comparison of antibacterial effect of thiazole, imidazole and tetrahydropyridine derivatives as well as silver nanoparticles on three gram negative bacteria, Proteus mirabilis, Acinetobacter baumannii and Shigella dysenteriae.
To evaluate the antibacterial effect, the disk diffusion method was applied to measure the growth inhibition zone diameter and broth microdilution was performed to determine the minimum inhibitory concentration (MIC).
Results showed that thiazole, imidazole and tetrahydropyridine derivatives as well as silver nanoparticles had no inhibitory effect on Acinetobacter baumannii. Also there was no inhibitory effect from imidazole and tetrahydropyridine compounds beside 6a-c derivative of thiazole on bacteria. In this study the halo diameter of 17.3 and 18.5 mm and MIC of 125 and 62.5 µg/ml were recorded for inhibitory effect of 6d derivative of thiazole on Proteus mirabilis and Shigella dysenteriae, respectively. Furthermore, the silver nanoparticle had inhibitory effect with halo diameter of 13.4 and 15.2 mm and MIC of 1125 and 562.5 µg/ml on Proteus mirabilis and Shigella dysenteriae, respectively.
In this study the antibacterial potency of thiazole derivative was proved in comparison to silver nanoparticle.

The novel stronger antibacterial compounds such as the thiazole and pyrimidine derivatives are needed in order to remove the threat of bacterial antibiotic resistance in zoonotic aquatic bacterial pathogens. In this study, we evaluated the inhibitory effect of the new benzothiazole and tetrahydropyrimidine derivatives against three important zoonotic aquatic pathogens including Streptococcus iniae, Edwardsiella tarda and Aeromonas hydrophila.
Material & Benzothiazole and tetrahydropyrimidine derivatives were synthesized and dissolved in DMSO with a concentration of 8129 μg/mL. Then, the disk diffusion and broth microdilution methods were applied to evaluate the antibacterial effects. Results were recorded as the minimum inhibitory concentration (MIC) and the growth inhibition zone diameter.
The study showed that the two tetrahydropyrimidine derivatives had no inhibition effects on all of the studied bacteria. Moreover, no inhibitory effect was observed from the three banzothiazole derivatives against A. hydrophila. However, the benzothiazole derivatives showed significant inhibitory effect against S. iniae and E. tarda with MIC of 256-1024 µg/mL and the growth inhibition zone diameter of 4.3±0.3-18.2±0.1 mm.
The antibacterial effect of the new banzothiazole derivatives was confirmed on S. iniae and E. tarda pathogens for the first time.

Along with increasing antifungal resistance in recent years, using novel antifungal compounds have been extended considerably caused researchers have been investigated new antifungal compounds. Thiazole derivatives and silver nanoparticles are chemical compounds with antifungal effects which have attracted researchers recently. In this study the inhibitory effects of four thiazole-thiazolidine derivatives were studied on Aspergillus niger, Candida albicans and Fusarium solani.
In this study, at first, thiazole derivatives and silver nanoparticles were prepared as a solution. Then disk diffusion three times was used for calculation of growth inhibition zone diameters and serial dilution method in microplates was used to assess minimum inhibitory concentrations (MICs) for three times in-vitro.
Results showed that 6a-c thiazole derivatives and silver nanoparticles had no significant inhibitory effects on all of the fungi, but growth inhibition zone diameters and MIC were reported 16 mm and 64 µg/ml for 6d thiazole derivative on Aspergillus niger.
In this study only existing of thiazole ring don’t have inhibition effects but the inhibitory effects of these compounds depend on cross linking to this ring; for example connection of oxygen to thiazole ring in 6d derivative is a proof to this claim, and also diameter and number in silver nanoparticles have important role in antifungal effect.

Rhodoccocus equi, Brucella abortus, and Pasteurella multocida are important veterinary bacterial pathogens that in recent years have been resisted to current antibiotics, and this problem threats the livestock industry. To control this resistant microorganisms, use of new antibacterial compounds, such as thiazole derivatives, in veterinary is necessary.
In this study, antibacterial effects of thiazole derivatives on Rhodoccocus equi, Brucella abortus, and Pasteurella multocida were evaluated.
Synthesized thiazole derivatives were prepared in DMSO, then the disk diffusion method was used to measure growth inhibition zone diameter and the broth microdilution method was applied to determine the minimum inhibitory concentration (MIC).
Results showed that thiazole derivatives had no significant inhibitory effects on B. abrotus, while they had inhibitory effects on R. equi and P. multocida with inhibition zone 12.7±0.4 -30.1±0.2 mm and MICs 32- 256 μg/ml.
Results of this study indicate that thiazole derivatives have considerable inhibitory effects on R. equi and P. multocida as veterinary bacterial pathogens.

Proteus vulgaris is one of a nosocomial pathogens and recently, the spread of antibiotic-resistance of this bacterium has encouraged researchers to investigate new antibacterial agents against it. Thiazole, imidazolidin and tetrahydropyridine derivatives are new antibacterial compounds that their inhibitory effects have proved against many pathogenic bacteria. In this study, antibacterial effects of 15 new thiazole, imidazolidin and tetrahydropyridine derivatives has evaluated against P. vulgaris.
In this study, a solution of all the synthesized derivatives were prepared in DMSO as solvent, the antibacterial effects of derivatives were evaluated using disk diffusion and microdilution methods in order to measure zone diameters of bacterial growth inhibition and determine the minimum inhibitory concentration (MIC), respectively.
Results showed that imidazole and tetrahydropyridine derivatives 9a-g and thiazole derivatives 6a-c, 10a and 10c had any inhibitory effect on P. vulgaris, only, inhibitory effects of three thiazole derivatives 6d, 9 and 10b were observed with zone diameters of bacterial growth inhibition of 22.1±0.2, 10.2±0.1 and 4.3±0.1 mm and MIC of 128, 512 and 1024 μg/ml on P. vulgaris, respectively.
In this research, antibacterial effect of some new thiazole derivatives (6d, 9 and 10b) was proved on standard strains of P. vulgaris and to use the compounds as medicines, their effects must be evaluated on drug-resistant strains of P. vulgaris in future studies.

Pseudomonas aeruginosa is an opportunistic bacterial pathogen and one of themost frequent bacterial agents in nosocomial infections. It causes different types of infections including urinary tract infections and bacteremia. This bacterium has manypathogenic factors including; exotoxin A، lipopolysaccharide، phospholipase C، pili،elastase، flagelline، alginate، and alkaline protease. In this study،frequency of fliC and algD genesin clinical Pseudomonas aeruginosa strainsisolated from nosocomial infections were analyzed. 100 Pseudomonas aeroginosa strains were isolated in clinical samples of Amiralmomenin Imam Ali hospital in Zabol. The isolates were identified by biochemical methods، afterwards DNAs were extracted. In order to detect presence of fliC and algD genes among the isolated bacterial strains، special primers were designed and PCR was performed. Results showed 80% strains have fliC and 95% algD، respectively. The results of our study confirm that fliC and algD genes as important virulence factor of Pseudomonas aeruginosa، present in isolated bacterial strains considerably. The results of our study showed that alginate gene is so important in pseudomonas aeroginosa strains isolated from urinary tract infectionsand burnwound infections and it can be used for detection of bacteria and also can be used as a vaccine target against this bacterial pathogen.

Due to increasing of resistant to current antibiotic by bacterial pathogens, using of new antibacterial compound such as thiazole derivatives is necessary. In this test study we evaluate the inhibition effects of new thiazole derivatives on E. coli, S. typhimurium, B. cereus and L. monocytogenes. Synthesized thiazole derivatives were prepared in DMSO. Well method was used for the calculation of growth inhibition zone diameters and serial dilution method in microplates was utilized to assess minimum inhibitory concentrations (MICs). Inhibition effects were variable whit MIC 0-1000 µg/ml and inhibition zone 0-17.1 mm, so that, derivative 4 showed the best MIC on B. cereus andL. monocytogenes and derivative 6b showed the best MIC on L. monocytogenes. Thiazole derivatives showed significant inhibition effects on B. cereus and L. monocytogenes in comparison with E. coli and S. typhimurium. Only derivative 4 showed inhibition effects on gram-negative bacteria, also antibiogram tests showed higher resistant in E. coli and S. typhimurium. Our results show that benzo [d] thiazol derivatives have significant effective inhibition on bacterial pathogen especially on gram-positive bacteria, maybe existence of a thioamide chain bond to a thiazole ring has important role in antibacterial activity of these thiazole derivatives. In order to use new thiazole derivatives against food bacterial pathogens, they need more tests and in-vivo experiments.