abdolmajid mohammadzadeh

Mastitis is a well-recognized and costly disease of dairy cattle. Mycoplasma bovis is one of the most important causal agents of mastitis in dairy cows. In respect to the importance of mastitis caused by Mycoplasma, the objective of the present study was to evaluate of presence of M. bovis in bulk milk of dairy cattle farms of Hamedan province, Iran. For this purpose, a total of 125 bovine bulk tank milk samples were collected from 31 dairy farms of Hamedan, Iran. After that, California Mastitis Test (CMT) and Somatic Cell Count (SCC) were done on the milk samples. Then using DNA extraction kit, the total DNA was extracted from each sample. The PCR followed by nested PCR (nPCR) was performed for specific detection of M. bovis. Based on PCR for genus detection, totally, 19 out of 125 (15.2%) bulk tank milk samples were contaminated with Mycoplasma spp. In addition, 11 samples (8.8 %) were contaminated by M. bovis based on nested PCR results. Moreover, the results showed that 26 of 125 bulk milk samples (20.8 %) and 102 of 125 bulk milk samples (81.6 %) have high rate score by CMT and SCC, respectively. Statistical analysis showed a positive correlation between CMT and SCC results. In the present study, the presence of M. bovis in the bulk tank milk samples suggests that more hygiene practices are required to avoid transmitting this pathogen among dairy cow herds of Hamadan region. According to the presence of Mycoplasma in bulk tanks of this region, the present study suggested that the frequency of Mycoplasma contamination in individual cows be determined.

Staphylococcus aureus, as a major food-borne pathogen, is the most commonly isolated bacterium from bovine mastitis. However, some S. aureus strains exhibit a high rate of antibiotic resistance, among which, methicillin-resistant S. aureus (MRSA) is very important. The present study was conducted to isolate, characterize, and determine the antibiotic resistance profile of MRSA strains in milk.

Staphylococcus aureus strains were isolated and identified from 415 milk samples collected from apparently healthy cattle in Hamedan province, Iran. Molecular characteristics of the strains were identified using multiplex polymerase chain reaction (PCR) and the antibiotic resistance profile of the isolates was determined by Kirby-Bauer disk diffusion susceptibility test.

A total of 76 S. aureus strains were isolated and identified. The PCR results indicated that 50 (65.78%) isolates possessed mecA gene and were found to be MRSA strains. Twelve isolates (15.78%) showed phenotypic resistance to oxacillin in disk diffusion method. All 76 S. aureus isolates (100%) were resistant to penicillin and susceptible to ciprofloxacin and gentamicin.

The results of the present study indicated that bovine milk may contain MRSA strains and this is worrying as these isolates may transfer multi-drug resistance to the isolates that circulate among humans, animals, and food chains.

Increasing antibiotic resistance is a global health problem. In recent years, due to the indiscriminate use of antibacterial compounds, many bacterial pathogens, including staphylococci, members of the Enterobacteriaceae family including Klebsiella pneumoniae and bacteria such as Pseudomonas aeruginosa and Acinetobacter baumannii have become multi-drug resistant. Consequently, it is important to explore alternative approaches for eliminating resistant strains. Bacteria synthesize low-weight molecules called siderophores to chelate iron from the environment as a vital element for their growth and survival. One way to deal with resistant bacterial strains is to utilize siderophore-mediated iron uptake pathways as entrance routes for drug delivery. Therefore, the production of drugs with Trojan horse strategy in the form of conjugated siderophore-antibiotic complexes has recently received much attention for dealing with resistant isolates. In this review, we discuss the efficacy of siderophore-antibiotic conjugates as a Trojan horse strategy for eliminating drug-resistant pathogens.

Members of the genus Mycoplasma are known as pathogens causing respiratory disease in cattle world-wide.

The present study aimed to investigate mycoplasmal infection in the lung tissue of cattle slaughtered in Hamadan industrial abattoir, Iran, using molecular and histopathological methods.

A total of 108 tissue samples were collected from the cranioventral parts of the cattle lung during March 2015-February 2016. The specimens were subjected to a polymerase chain reaction (PCR) and histopathological examinations. The PCR-positive samples were tested subsequently for Mycoplasma bovis and Mycoplasma dispar using nested PCR assay.

Nine (8.33%) samples contained the DNA of genus Mycoplasma, among which, five and one showed the DNA sequences of M. bovis and M. dispar, respectively. Pathological changes, such as caseonecrotic lesions, interstitial pneumonia, lobar bronchopneumonia, and bronchial atelectasis were observed in 24 (22.22%) tissue samples. All the PCR-positive lungs demonstrated at least one pathological manifestation. However, not every pathognomonic tissue changes were concomitant with the presence of the DNA of Mycoplasma spp.

It could be concluded that M. bovis and to a lesser extent M. dispar are relatively common in the cattle population of the western part of Iran. Therefore, these pathogens should be taken into consideration whenever respiratory problems are evident in cattle

Prevention of brucellosis in humans is based on the vaccination of animals. Given that Rev.1 vaccine is one of the most effective vaccines for preventing and controling brucellosis in sheep and goats, the present study was conducted to evaluate and compare humoral immune responses of sheep against Razi Institute and Spanish (CZV) Rev.1 brucellosis vaccines.

To do the study, 6 sheep were prepared and divided into 2 groups, and blood samples were then collected on day zero. The animals of each group were subcutaneously vaccinated with one dose of Razi Institute and Spanish (CZV) Rev.1 vaccines followed by collecting blood samples on days 30, 60, 90, 120, 150, and 180 post vaccination. Sheep serum samples were then tested using Rose Bengal, Wright, and 2-Mercaptoethanol assays and the data were statistically analyzed.

The results showed that the highest titers of Wright and 2-Mercaptoethanol tests were observed 30 days after vaccination. However, no statistically significant difference was observed between humoral immune responses of sheep vaccinated with either Razi Institute or Spanish (CZV) Rev.1 vaccines (P > 0.05).

Given the similar results of both vaccines in stimulating the humoral immune system in the target species and the indigenous Razi vaccine production technology, as well as its lower price compared to the imported one, this native vaccine can certainly be used for immunizing livestock in our country. This can ensure the country’s independence, boost national vaccine production, and prevent the outflow of currency

S. aureus is a major cause of food borne diseases throughout the world. The aim of the present study was the identification of source contamination and tst gene in Staphylococcus aureus isolated from food of animal origin in Hamedan city. In this study, the contamination sources of 65 S. aureus isolates which had previously been isolated from cream pastry (45 isolates) and traditional Iranian white cheese (20 isolates) were evaluated using biotyping method. Meanwhile, the identification of tst gene by PCR method and susceptibility of the isolates against several antibiotics was examined using standard disk diffusion test. Of the 65 biotyped isolate, 52.3% (34 isolate) and 44.6% (29 isolate) belonged to the host specific (HS) and non-host specific (NHS) biotypes, respectively, and 3.1% isolates (2 isolates) were not placed in in certain types. Besides, human ecovars in cream pastry and bovine ecovars in cheese sample were predominant. The prevalence rate of tst gene in the isolates is 4.6% (3 isolate), and according to the results of antimicrobial susceptibility testing, HS biotypes showed higher resistance than NHS biotypes.

Due to the abundance of human and bovine ecovars in cream pastry and cheese, respectively, it maybe the contamination of cream pastry by human and cheese by bovine have occurred. Also, because of high antibiotic resistance and existence of tst gene among HS biotypes and the possibility of their circulation in the community can have a potentially alarming effect on general health of community.

Staphylococcus aureus is the major causative agent of hospital-acquired and community-acquired infections. These bacteria produce a wide variety of exotoxins, including Toxic Shock Syndrome Toxin (TSST) and virulence factors, which are thought to contribute to its pathogenic potential.
The aim of this study was to identify tsst gene in S. aureus isolated from patients and healthy carriers.
In this cross-sectional study, a total of 60 human S. aureus isolates were collected from individuals referred to Shahid Beheshti hospital (patients, n = 40) and healthy farm workers (n = 20) in Hamadan province of Iran. Thereafter, DNA samples were extracted using the phenol-chloroform method and the samples were investigated for tsst gene using a specific PCR assay.
The DNA fragment corresponding to the tsst gene (326 bp) was observed in 45% (9 out of 20) of S. aureus isolated from healthy farm workers; while, 22.5% (9 out of 40) of patients’ isolates were found to be positive for tsst gene, which indicated that in total 30% of the isolates possessed this gene.
The results of the present study showed the high prevalence of the tsst gene among S. aureus isolated from healthy farm workers and patients. Therefore, appropriate precautions must be considered to decrease the risk of transmission of such isolates to other humans.

Determining the genetic relationship between S. aureus isolates is important for epidemiological surveillance and control of infections caused by this bacterium. The present study was conducted to determine polymorphisms of coagulase gene (coa) among S. aureus isolates from pastry and cheese samples using restriction fragment length polymorphism (RFLP) analysis.

Overall, 65 S. aureus isolated from pastry (n=45) and cheese (n=20) samples were examined for the coa gene by polymerase chain reaction (PCR). PCR products were digested with AluI enzyme and the products were assessed using gel electrophoresis.

Except for two isolates, all isolates were positive in coa-PCR and produced four different PCR products, with molecular sizes ranging from 570 to 970 bp. Overall; five distinct RFLP patterns were detected (I-V). Although pattern types I and III were present in isolates from both samples, types I and IV were mainly present in isolates from cheese and pastry samples, respectively.

PCR-RFLP analysis of the coa gene indicates that S. aureus isolates from pastry and cheese samples may be originated from different sources. However, as one pattern type was predominant in each group, it can be concluded that majority of the isolates may have the same origin.

Pigeons can be carriers for some human and animal pathogens, one of the most important of which is Escherichia coli.
This bacterium is responsible for outbreaks of many human diseases. Our objective was to determine the prevalence of Escherichia coli in cloacal area of pigeons in Tehran city (Iran), and determine the prevalence of some virulence genes and also antibiotics resistance pattern of isolates.
Altogether 117 samples of pigeon feces were collected from cloacal swab. The identification of bacteria was done by culture on differential culture media. Then antibiotic susceptibility test was performed by disk diffusion method. Isolates were tested for the presence of virulence genes stx1, stx2, eae and hlyA using multiplex polymerase chain reaction.
Escherichia coli were detected in 82.9% of 277 samples from pigeons. Sulfamethoxazole was the least effective drug (85.6% resistance), followed by tetracycline (83.5%). No resistance was detected to co-amoxiclav. The prevalence of stx1, stx2 and eaeA is 3.09%, 6.18% and 2.06% respectively and hlyA was not found in any of isolates.
The frequency of stx1 and stx2 distribution in animals and birds is not well understood as yet. Due to the close relationship of humans with birds like pigeons and presence of STEC strains in apparently healthy birds, necessitates considering precise regulations to restrict and prevent the prevalence of this life- threatening virus in Iran.

Staphylococcus aureus causes a wide range of diseases in humans and animals. Rapid and precise typing of S. aureus is a prerequisite for epidemiological surveillance and controlling of infection caused by this bacterium. In this case, biotyping is a simple, cheap, and effective method for epidemiological investigations. A total of 143 S. aureus strains isolated from human (40 patient strains, 20 carrier strains) and bovine raw milk samples (83 strains from 7 herds) were genotypically confirmed by polymerase chain reaction (PCR), and phenotypically assessed using a biotyping method to determine the possible sources of contamination. Of 143 examined strains by the biotyping method, 14 strains belonged to human ecovars, while 11, 25, and 12 strains were classified as bovine, sheep, and poultry ecovars, respectively. Meanwhile, 61 strains were found to be non-host specific (NHS) biotypes, and 20 strains were not typable by this method. The results of the present study showed that in Hamedan province, humans and bovine raw milk samples were frequently contaminated by strains belonging to the K-B-CV:C biotype. However, among host specific (HS) biotypes, sheep ecovar was the most common biotype. The results indicated possibility of transmission of different ecovars among various species.

Rabies is an almost invariably fatal disease that is associated with animal bites. Hence, gathering data about cases of animal bites can help in clarifying the relative status of the disease.
This study was conducted to provide an epidemiological overview on animal bites and rabies occurred in Hamedan province, Iran, during 2011 - 2013.
This cross sectional descriptive study was conducted in Hamedan province, Iran. The information was retrieved from the vice-chancellery for health (Hamedan University of Medical Sciences) and veterinary directorate general of Hamedan province. The data were analyzed using the SPSS software. The Chi-square test was used to determine statistically significant differences with P values less than 0.05.
There was just one report of rabies death during the mentioned period. The total number of reported animal bites was 14327 with the incidence of 2.69 cases/1000 individuals, which included 3287 (22.9%) women and 11040 (77.1%) men. Of these cases, 9868 (68.9%) resided in rural areas, while 4459 (31.3%) were urban residents. Most animal bites, 3516 (24.54%) cases, occurred in the 20 - 29 year-old age group. The lower limbs injuries were significantly higher than other sites with 7462 (52.08%) records. In addition, the majority of people were bitten by dogs (11040 cases, 77%).
This study indicated that the incidence of animal bites was increased during 2011 - 2013 in Hamedan province. Therefore, it seems necessary to take appropriate educational programs along with both pre-exposure immunization and postexposure prophylaxis to control this infection in the region.

Staphylococcus aureus is one of the most important nosocomial pathogens. Pathogenicity of this organism is attributed to various virulence factors such as surface adhesion proteins, the ability to produce toxins and enzymes, rapid development of drug resistance and biofilm formation. The present study was conducted to investigate some of the virulence factors of S. aureus isolates.

A total of 30 isolates of S. aureus were collected from clinical samples of patients hospitalized in Shahid Beheshti hospital of Hamedan. Identification of bacteria was done using biochemical (catalase, coagulase and DNase) and molecular (PCR) tests. Thereafter, antibiotic susceptibility of the isolates and their ability to produce hemolysin, beta-lactamase and biofilm were assessed using disk diffusion, blood agar medium, acidimetric and microtiter-plate tests, respectively.

Hemolysis activities of the isolates on sheep blood agar showed that 8 (26.66%), 14 (46.66%) and 15 (50%) out of 30 isolates, produced α-, ∂- and β-hemolysins, respectively. While, using human blood agar media, the prevalence of these toxins were 40%, 53.33% and 13.33%, respectively. Twenty one isolates (70%) were found to be beta-lactamase producer using the acidimetric test. Meanwhile, the results of antibiotic susceptibility test indicated that penicillin was the less effective antibiotic (90% resistance). However, none of the isolates was resistant to vancomycin. Moreover, regarding to biofilm formation, 14 (46.66%) isolates strongly produced biofilms.

The results of this study revealed high frequencies of the virulence factors among the examined S. aureus isolates, specially the ability of biofilm formation and antibiotic resistance.

Methicillin-resistant staphylococcus aureus (MRSA) is considered as a major pathogen in public health concern. The objectives of this study were to firstly determine antibiotic sensitivity among Staphylococcus aureus isolated from traditional Iranian white cheese during 2015 from Hamedan province of Iran; and secondly to estimate the presence of methicillin-resistant S. aureus. This cross-sectional study was done by collecting 120 Iranian white cheeses (traditional and industrial) which were available in different markets; and tested for the presence of S. aureus by culture methods. The obtained isolates were subjected to disc diffusion antimicrobial susceptibility tests followed by PCR detection of the mecA gene. Out of 120 examined cheese samples, 19 samples (31.67%) were contaminated with S. aureus. The highest rate of antibiotic resistance was observed for penicillin, as all of the 19 isolates (100%) were found to be resistant to this antibiotic using disk diffusion method. Three out of 19 S. aureus isolates (15.7%) were phenotypically resistant to methicillin (disk diffusion), while 4 (21.05%) of them were genotypically confirmed as MRSA strains. Furthermore, none of the isolates were found resistant to vancomycin. The results of the study confirm the presence of methicillin resistant strains of S. aureus in Iranian white cheese. It should be considered to constitute a potential health risk for consumers, suggesting usage of more stringent hygiene measures.

Biofilm is a complex community of microorganisms residing within a polysaccharide and/or protein matrix. Biofilm can be produced by microorganisms such as bacteria and fungi. Both gram positive and gram negative bacteria have this ability. Resistance of biofilm to antimicrobial agents is becoming a global issue. Bacterial biofilms are important in various aspects such as chronic human infections, dental plaque, infection of indwelling medical devices like catheters; animal and plant diseases and they are also a major problem in industries and food processing units. It is estimated that more than 80% of all microbial infections are caused by biofilms. The aim of this study was to describe biofilm and the importance of bacterial biofilms. We discoursed about resistance of bacteria in biofilm phase; and finally, the known anti-biofilm mechanisms have been discussed. Also, due to the importance of plant compounds for treatment of bacterial infections and as, there has been increased interest in controlling of bacterial infections by these substances, some recent studies in this field (plant compounds as anti-biofilm agents) have been expressed.

Neospora caninum is a worldwide distributed pathogen which causes abortion in cattle leading to economic loss in the cattle industry. The aim of this study was to determine the seroprevalence of N. caninum antibodies in the native cattle slaughtered in various areas of Kurdistan province (western Iran) from September 2010 to September 2011. Serum samples from 368 cattle slaughtered in seven slaughterhouses in this region were taken for detection of anti-N. caninum antibodies using commercial N. caninum ELISA kit. Antibodies to N. caninum were found in 29 samples (7.80%). The present study was the first report of Neospora infection in this region and indicated that native cattle of Kurdistan province were exposed to this parasite.