Detection of Mycoplasma gallisepticum, Isolation, and Determination of Tylosin Susceptibility of Isolates from Commercial Chickens.

Mycoplasma gallisepticum (MG) is a contagious avian pathogen that causes financial losses to the poultry industry. Isolation of the pathogen is difficult and time-consuming, and therefore, far from a routine method. Serological testing methods to detect antibodies resistant to MG are widely used in routine diagnosis. Tylosin is a class of macrolide antibiotics tremendously administered in veterinary medicine for the treatment of mycoplasmosis and prophylaxis. This study aimed to detect MG by immunoassay testing, culture, and polymerase chain reaction (PCR) in commercial poultry farms and to investigate the tylosin susceptibility of the isolates. To verify the presence of antibodies resistant to MG, 750 blood samples were randomly collected from 38 broiler farms from 2019 to 2022 in Mazandaran and Golestan provinces, Iran, and rapid slide agglutination (RSA) assay was performed. Positive results were analyzed by the enzyme-linked immunosorbent assay (ELISA) for further investigation. Here, 920 swab samples were collected from 38 non-vaccinated commercial farms for culture, and PCR tests were performed for the isolated strains. The activities of tylosin were tested in vitro against these isolates using the broth microdilution method. The lowest antibiotic concentration that resulted in a color change was considered the minimum inhibitory concentration (MIC) value. Twenty-four (63.1%) farms were positive in the RSA test, and 21 (55.2%) farms were positive in the ELISA test. Nine (23.68%) of the farms grew on culture media, and 8 (21.05%) were detected as Gallisepticum species by PCR. The geometric mean of MIC for tylosin was 5.75 µg/ml, MIC50 was 4 µg/ml, and MIC90 was 8 µg/ml. The results indicated that commercial farms were infected with MG. Considering the ability of MG to spread and the probable use of the RSA test as a rapid and cheap method, it can be argued that ELISA and RSA serological tests can be used to find MG in poultry flocks, and the positive result should be confirmed by standard microbiological tests or PCR. It was also found that the isolated parts of MG changed their sensitivity to tylosin, indicating the need for routine testing to optimize treatment dose and efficiency.

Comparison the effects of probiotic and prebiotic as antibiotic alternatives on Salmonella colonization, performance, and egg quality in laying hens challenged with Salmonella enterica serotype Enteritidis.

Background: Consumption of contaminated eggs with Salmonella enterica serotype Enteritidis (SE) cause gastroenteritis in human. Aims: The present study examined the effect of probiotic and prebiotic compared to antibiotic on the colonization of SE in the ceca, and the quantity and quality of produced eggs in the laying hens challenged with SE. Methods: One hundred Hy-Line W-36 laying hens with 44-week-olds were studied for 13 weeks in a randomized complete block design containing five treatments and four replicates with five birds in each replicate. Treatments included: negative control, positive control, and antibiotic: diets containing antibiotic (Oxytetracycline 0.15 g/kg diet), probiotic (Bactocell® 0.1 g/kg diet), and prebiotic (Diamond V Original XPCTM 1.25 g/kg diet). All experimental groups except negative control were challenged with 1 ml of suspension solution containing 1 × 107 CFU/ml SE by oral gavage at the start of the ninth week of the experiment. Laying performance traits and cecal bacterial population were measured at the end of each week. Results: Probiotic and prebiotic showed a greater effect in the reduction of yolk cholesterol and blood cholesterol level before and after challenge with SE, respectively (P<0.05). In pre-challenge period, treatments had no effect on the cecal bacterial population; but after the challenge, three dietary supplements decreased the colonization of SE in the ceca of laying hens, and prebiotic showed more preventive effect (P<0.05). Conclusion: The result of this study showed that the prebiotic can be effective in reducing and preventing SE colonization in laying hens and act as an alternative to antibiotics.

Clonal relatedness and antimicrobial susceptibility of Salmonella serovars isolated from humans and domestic animals in Iran: a one health perspective.

Background: Salmonellosis is one of the most important zoonotic diseases in humans and animals worldwide. Aims: The main objective of this study was to report serovars, clonal relatedness, and antimicrobial resistance of Salmonella strains isolated from human, different animal hosts including pigeons, broilers, cattle, camel, parrots, and hamsters in different regions of Iran. Methods: Twenty-four Salmonella isolates were confirmed at the genus level by biochemical tests and polymerase chain reaction (PCR) by showing the presence of invA gene. Serovars were determined and their clonal relatedness was assessed by RAPD-PCR and antibiotic resistance profiles. Results: Overall, Salmonella Typhimurium was the most prevalent serovar (45.8%, 11/24), which was recovered from humans, pigeons, and camels. Salmonella Enteritidis (29.2%, 7/24) was the second common serovar that was recovered from cattle, broilers, humans, and hamsters. Salmonella Infantis (12.5%, 3/24) belonged only to broiler sources, and Salmonella Seftenberg (12.5%, 3/24) was isolated from eggs and a parrot. The major RAPD pattern was VI (33.3%) in which the two S. Typhimurium isolates (belonged to humans and pigeons) exhibited similarity in both RAPD pattern and resistance profile. Antimicrobial susceptibility test showed full resistance to tylosin and erythromycin (100%, 24/24). All isolates (100%, 24/24) were susceptible to ceftriaxone, cefixime, and gentamicin. In total, 75% of the isolates were multi-drug resistant (MDR) and revealed 15 different antimicrobial resistance profiles (R-type). Conclusion: This study supports the potential transmission of Salmonella serovars via animal contacts. Thus, it is necessary to establish a national systematic monitoring program with one health approach for controlling Salmonella infections.

Detection of Canine Parvovirus Type 2 by Designing Multiple Methods and Genetic Characterization in Iran.

Canine parvovirus infection is the most highly infectious in dogs younger than six months. Our study aimed to design and optimize an In-house PCR Assay for Rapid Detection of parvovirus type 2 and compares it with REAL-TIME PCR and LAMP Assay and phylogenetic analysis. The virulence gene selected for the categories was vp2 for CPV-2. PCR products were cloned in pTZ57R/T plasmid for preparation of positive control. Determination of the specificity of primers was done with the negative control virus genomes, and the limit of detection was determined for the Homemade PCR, REAL-TIME PCR, LAMP, and to perform a phylogenetic study using partial vp2 gene sequences. Added analysis of PCR products using agarose gel electrophoresis for the vp2 gene showed 485bp, and GAPDH 900 bp bands, respective amplification using negative control genomes as template was negative. The least detectable copy number for the vp2 gene in a 25 µl PCR reaction equals 19 copies by homemade PCR, LAMP, and REAL-TIME PCR 25 and 21 copies, respectively. The phylogenetic analysis for the five field sequences formed three distinct clusters. The in-house PCR has advantages such as high specificity, sensitivity, and the ability to detect major CPV-2 pathogens. This assay may replace the previous laboratory methods and work as an essential supplement to the more time-consuming assays. Phylogenetic analysis is necessary for epidemiological studies to control and prevent disease.

Design and Development of a New Method for the Production of Nanotoxoids from Clostridium Perfringens Beta Toxin.

In recent years, a nanoparticle-based strategy has shown that non-denatured protein toxins can be used to enhance the appropriate immune response. Once the toxin reacts between the nanoparticles and the protein (toxin), it loses its toxicity because it does not attach to its ligand at the cell surface. The results of the nanoparticle and toxin complex show that the nanoparticles facilitate the internal release of the toxin. Clostridium perfringens beta toxin is produced by Clostridium perfringens type B and C, and diarrhea is the most important disease caused in newborn lambs. When beta toxin forms a complex with nanoparticles, the reaction between the toxin and the nanoparticle leads to the formation of a new form of nanoparticle in which the toxin loses its lethality due to its involvement; therefore, it becomes a toxoid. The nanoparticles used in this research are of poly lactic-co-glycolic acid (PLGA) type, one of the most developed biodegradable polymers. This study aimed to isolate and purify Clostridium perfringens beta toxin and produce its complex with PLGA nanoparticles to form a non-toxic structure. In this study, Clostridium perfringens beta toxin type B was isolated using ammonium sulfate precipitation and gel filtration chromatography. Toxin assay was performed in vivo (lethal dose [LD50]) and in vitro by sodium dodecyl sulphate-polyacrylamide gel electrophoresis at each stage, and the quantity of purified toxin was calculated to be 10 mg/ml. Afterward, the beta toxin antigen was used as the basis for the preparation of nanotoxoid candidates with nanoparticle formulation. Moreover, the PLGA polymer and water-oil-water methods were used to fabricate nanoparticles. Under optimal conditions, nanoparticles without antigen with an average size of 100 nm and zeta potential of -23.28 mV, as well as nanoparticles containing antigen with an average size of 120 nm and zeta potential of -18.2 mV, were prepared. When nanoparticles are injected into mice with the beta toxin, the toxin becomes a toxoid with no toxicity effects, and it cannot bind to its receptors and reveal its effects. In this study, the mice showed mild symptoms in one case, and none of them died. The beta and PLGA toxin model could also be applied as a candidate to study the release and immunization of the target animal. In order to achieve antigen regulation using natural polymers, it is recommended to conduct a comparative study between nanoparticles based on natural polymers.

Development of New Modified Simple Polymerase Chain Reaction and Real-time Polymerase Chain Reaction for the Identification of Iranian Brucella abortus Strains.

Brucellosis is primarily a worldwide zoonotic disease caused by Brucella species. The genus Brucella contains highly infectious species that are classified as biological threat agents. In this regard, the identification of Brucella can be a time-consuming and labor-intensive process posing a real risk of laboratory-acquired infection to the laboratory staff. This study aimed to present a novel conventional and real-time polymerase chain reaction (PCR) assay for the identification of Brucella abortus strains. Regarding this, two primers (bru ab2) were designed based on the unique loci encoding autotransporter-associated beta strand repeat-containing protein (ID:YP00113760). A total of 56 Brucella strains (e.g., reference, vaccinal, and field isolates) and Yersinia enterocolitica, as a non-Brucella isolate, were evaluated in conventional and real-time PCR systems. The results of the study indicated that 0.4 ng and 400 FG of genomic DNA of B. abortus strains can be detected by conventional and real-time PCR, respectively. The primers, bru ab2, were suitable for both PCR methods. Both methods were specific for the detection of all strains of the bacterium; however, real-time PCR assay was 1000-fold more sensitive than the conventional PCR method. Therefore, this new detection system could be a suitable selective modified method for the accurate identification of all B. abortus strains.

Serotype Distribution and Antimicrobial Resistance of Salmonella Isolates in Human, Chicken, and Cattle in Iran.

Salmonellais a foodborne zoonotic enteric bacterium able to infect both humans and animals. This study aimed to identify the antimicrobial resistance of Salmonella serovars isolated from human, cattle, and poultry. Moreover, we investigated the probable transmission trends of antibiotic-resistant Salmonella isolates from food animals to human. A total of 242 Salmonella isolates collected from various human and animal sources were serotyped. The polymerase chain reaction was performed to detect the invA virulence gene. The isolates were subsequently tested against 14 antimicrobials and the resistance rates among the isolates from three sample sources were statistically analyzed by the Chi-Square test. Serotyping revealed the isolates belonged to various serovars with the dominance of Enteritidis (37%), Typhimurium (35.3%), and Infantis (21.1%). A high frequency of resistance to streptomycin was observed followed by tetracycline, trimethoprim, sulfonamides, spectinomycin, chloramphenicol, florfenicol, ampicillin, kanamycin, ceftazidime, and cefepime. In addition, multidrug resistance was observed in more than 40% of the isolates. The results of the statistical analysis showed a significant relationship (P ˂ 0.001) between the rate of antibiotic resistance among the three sources of Salmonellaisolates. Furthermore, the antibiotic resistance had a statistical relationship between the different serotypes isolated from different sources. These findings demonstrate the possible transmission of resistance to human from animal sources. The prevalence of the Typhimurium, Enteritidis, and Infantis serovars in both human and animals suggested that Salmonella contamination in chicken and cattle may be the major source of salmonellosis in human. The high incidence of antibiotic resistance in Salmonellaisolates along with the close relationship between the antimicrobial resistance of animal and human isolates indicate the role of food animal products as an important source of resistance.

Phylogenetic Analysis of bor Gene in an Escherichia coli Strain 1378 (O78:K80) Isolated from an Avian Colibacillosis Case in Tehran, Iran.

Colibacillosis is known as a fatal bacterial disease resulting in a high level of commercial loss worldwide. This study amid to elucidate the sequence, genetic characteristics, and phylogeny of the bor gene in Escherichia coli (E. coli) strain c1378 (O78:K80) isolated from avian colibacillosis in Iran and develop a rapid and optimal polymerase chain reaction (PCR) molecular-based technique with specific primers to detect this gene in E. coli. A virulent avian E. coli (i.e., laboratory designation E. coli strain c1378) isolated from a chicken with systemic colibacillosis from a broiler farm in Tehran, Iran, in 2004 was used as a source of the bor gene. After DNA extraction, PCR method was used to amplify the bor gene. A 658 bp fragment of the bor gene was amplified, sequenced, blasted, and phylogenetically studied. The most similar sequences to the bor gene in E. coli strain c1378 were E. coli APEC O78, Enterobacteria phage HK630, and Escherichia coli BW2952, respectively. There was a high similarity between the bor gene in E. coli bacteria with their phage and plasmid. Moreover, a high similarity was observed between the bor and iss genes (approximately 92%) showing that they were homologous genes. In addition, the similarity analysis of different bacterial species, as well as their plasmid and bacteriophage, to the bor gene indicated that the highest similarity to O78:K80 was related to Paracoccidioides brasiliensis, Bacillus thuringiensis CT43 plasmid pBMB0558, and Salmonella enterica subsp. enterica serovar Kentucky strain CVM29188 plasmid, respectively. Altogether, the results of the present study confirmed the presence of the bor gene in the studied isolates and clarified its sequence, phylogenetic relationship, and similarities of E. coli strain c1378 (O78:K80) isolated from avian colibacillosis.

Distribution of Antibiotic Resistance Genes among the Phylogroups of Escherichia coli in Diarrheic Calves and Chickens Affected by Colibacillosis in Tehran, Iran.

Antibiotic resistance occurs in the endogenous flora of exposed population in addition to pathogenic bacteria. This study was conducted to evaluate the distribution of antibiotic resistance genes among 63 isolates of Escherichia coli of Escherichia coli (E. coli) in diarrheic calves and poultry. According to the results, B1 and B2 were the most prevalent phylogroups of E. coli in calves and poultry carcasses, respectively. Antimicrobial resistance was observed in 76% of the isolates, and 62% of the strains were multi-drug resistant. Antibiotic resistance in E. coli strains obtained from calves strains was significantly higher than those obtained from poultries. Additionally, the strains of B1 and D phylogroups had the highest and lowest antimicrobial resistance, respectively. At least one encoding gene for integrone was detected in 23 strains (36.5%) and Class I integron had the highest prevalence. Accordingly, this study gave baseline information on the magnitude of the resistance problem and its genetic background in E. coli from domesticated animals of the Tehran, Iran. Moreover, the power of oligonucleotide array technology in the discrimination of different genotypes during a short time was confirmed in this study.

Intraspecies Gene Variation within Putative Epitopes of Immunodominant Protein P48 of Mycoplasma agalactiae.

P48 protein of Mycoplasma agalactiae is used to diagnose infection and was identified as potential vaccine candidate. According to the genetic nature of mycoplasma and variable sensitivity in P48-based serological diagnosis tests, intra species variation of P48 nucleotide sequence investigated in 13 field isolates of difference province of Iran along with three vaccine strains. Samples were collected from sheep and goat and were cultured in modified PPLO broth. Two pair of primer employed to confirm genus and species of isolates and a pair of primer has developed to amplify the P48 gene. The sequencing results of PCR products were aligned and analyzed besides published sequences in GenBank. T-Cell and B-Cell epitopes and antigenicity of sequence were computationally predicted. The results have shown P48 nucleotide sequences are 99.9% identical in field isolates and vaccine strain of Iran, but analysis of GenBank published sequences have shown divergence up to 5.3% at the nucleotide level and up to 4.9% divergence in protein level of P48 sequences of Iran isolates and other available sequences in GenBank. Single nucleotide polymorphism exists in 89 positions and variable amino acid was observed at 25 residues. Phylogenetic analyses have shown that Mycoplasma agalactiae isolates fall into three main groups based on P48 nucleotide sequences. Immunoinformatics analysis of all available P48 nucleotide sequences have revealed that gene variation lead to differences in immunological properties, but the gene in Iranian isolates are conservative and stable. The sequence variation in epitopes can be underlying source of antigen heterogeneity as a result, affect serological tests accuracy. Due to the high level of divergence in worldwide isolates and high degree of similarity in P48 protein of Iranian isolates, designing recombinant P48 protein based on local pattern can increase the sensitivity and consistency of serological test.

Antibacterial, antibiofilm and antiquorum sensing effects of Thymus daenensis and Satureja hortensis essential oils against Staphylococcus aureus isolates.

AIMS: The present study was conducted to investigate the effects of Thymus daenensis and Satureja hortensis essential oils (EOs) on the planktonic growth, biofilm formation and quorum sensing (QS) of some Staphylococcus aureus isolates (strong biofilm producers). METHODS AND RESULTS: Minimum inhibitory concentration (MIC) of the EOs, inhibition of biofilm formation as well as disruption of preformed Staph. aureus biofilms were assessed. The antibiofilm activity of the EOs was determined using microtitre plate test (MtP) and scanning electron microscope (SEM). The QS inhibitory activity was also examined on the pregrown biofilms by gene expression analysis using quantitative real-time RT-polymerase chain reaction (PCR) of hld gene (RNAIII transcript). Moreover, tetrazolium-based colorimetric assay (MTT) was performed to detect cytotoxic effects of these EOs on the Vero cell line. Finally, the major components of the tested EOs were determined using Gas Chromatography-Mass Spectrometry (GC-MS). The MICs of T. daenensis and S. hortensis EOs against planktonic cells of the isolates were 0·0625 and 0·125 µl ml-1 respectively. The minimum bactericidal concentrations for both of the EOs was 0·125 µl ml-1 . The MtP test showed a significant inhibitory effect of the EOs on the biofilm formation and disruption at sub-MIC concentrations. These results were confirmed by SEM. Real-time PCR revealed a significant down-regulation of hld gene following treatment with MIC/2 concentration of S. hortensis EO. GC-MS analysis showed that carvacrol, terpinene and thymol were the major components of the applied EOs. CONCLUSIONS: As selected EOs did not show significant cytotoxic effects even up to tenfold of MIC concentration, the applied EOs seem to be good candidates for preventing of biofilm formation of Staph. aureus cells. SIGNIFICANCE AND IMPACT OF THE STUDY: The present study introduced T. daenensis and S. hortensis EOs as new antibiofilm, and S. hortensis EO as anti-QS herbal agents with natural origin against Staph. aureus.

Molecular identification of Salmonella Infantis isolated from backyard chickens and detection of their resistance genesby PCR.

This study aims at molecular identification of Salmonella Infantis isolated from backyard chickens and the detection of their antibiotic resistance genes. A total of 46 Salmonella-suspected samples isolated from backyard chickens of northern Iran were collected. Serotyping was done by the traditional method and then confirmed by PCR. Antimicrobial susceptibility of the isolates against 13 antimicrobial agents was determined by the standard disk diffusion method. There were 44 samples identified as Salmonella. Serotyping results showed that all 44 isolates belonged to serogroup C1 and serovar Infantis. The most resistance observed was to tetracycline and doxycycline (100%), chloramphenicol (79%) and florfenicol (72%). The floR, catI, tetA and tetG genes were used for the detection of florfenicol chloramphenicol and tetracycline resistance. In order to identify the phenotypic resistance in strains which showed resistance genes by PCR, colony PCR and culture on plates each containing antibiotic was performed simultaneously. All the Salmonella Infantis resistant to florfenicol and chloramphenicol harbored floR and catI. None of the Salmonella resistant to tetracycline carried tetA or tetG. The result of colony PCR and culture in antibiotic medium confirmed the results of PCR and indicated phenotypic resistance in these samples.

Gene disruption in Salmonella typhimurim by modified λ Red disruption system.

There are many techniques to knock out directed genes in bacteria, some of which have been described in Salmonella species. In this study, a combination of SOEing PCR method and the λ Red disruption system were used to disrupt phoP gene in wild type and standard strains of Salmonella typhimurium. Three standards PCR and one fusion PCR reactions were performed to construct a linear DNA including upstream and downstream of phoP gene and Kanamycin cassette. As a template plasmid, we used pKD4 which carries kanamycin gene flanked by FRT (FLP recognition target) sites. The resulting construct was electroporated into prepared competent cells of S. typhimurium. The transformants colonies related to the standard strain appeared on the LB-Km-agar plates after incubation, but there was no colony on LB-Km-agar plates corresponding to the wild type strain. The failure in transformation of the wild type strain may be because of inflexibility of the λ Red disruption system in this strain or its unique restriction-modification system. However, by this construct we are able to generate phoP mutant in many of the Salmonella species due to high homology of the phoP gene which exists in different species.

Molecular characterization, genetic diversity and antibacterial susceptibility of Escherichia coli encoding Shiga toxin 2f in domestic pigeons.

This study aimed to evaluate prevalence, characteristics, genotypic diversity and antibacterial susceptibility of Escherichia coli encoding Shiga toxin 2f in domestic pigeons in different provinces of Iran. A total of 117 faecal samples were collected from pigeons and were subjected to molecular detection of stx2f. In total, 20, 25·8, 21·4 and 9% of pigeons from Tehran, Ferdows, Garmsar and Babol cities carried stx2f+ isolates, respectively. Of the 460 E. coli isolates examined, 43 were stx2f+ and most also carried eae (95·3%) and astA (97·7%) genes. Some of the stx2f+ isolates harboured cnf (9·3%), but all were negative for stx1, stx2 (other subtypes) and ehly. Most Strains (90%) were assigned to B1 phylogroup and possessed Intimin-ß. Fingerprinting of the stx2f+ isolates using either enterobacterial repetitive intergenic consensus sequences (ERIC) or random amplified polymorphic DNA (RAPD)-polymerase chain reaction revealed seven distinct profiles by each method, with one prevailing (65·1 and 46·5%, respectively). By the combination of methods, 10 profiles were recognized. Ten isolates from different profiles were shown to belong to O20, O78 and O115 serogroups, and eight were 100% identical in the stx2f gene sequence. The strains were consistently resistant to amoxicillin and lincospectin and commonly resistant to tetracycline (88·4%) and doxycycline (74·4%). Overall, the results indicate a limited degree of genetic diversity in stx2f-harbouring E. coli from pigeons. Significance and impact of the study: Carriage of stx2f gene tends to be underreported in pigeon Escherichia coli isolates because most routine genetic and phenotypic tests cannot efficiently target this gene or detect the toxin. Nevertheless, pigeons frequently carry E. coli strains that are stx2f-positive, and this situation is not limited to any distinct geographical area. The current results suggest that genetic background of stx2f-encoding E. coli is distinct from most Shiga toxin-producing E. coli strains. However, the factors that contribute to host preferences and pathogenicity remain unclear. These findings have public health significance that should be addressed in future research.

Molecular detection of Leptospira spp. in the urine of cattle in northern Iran.

Leptospirosis is a zoonosis of worldwide distribution, caused by Leptospira interrogans and is considered as an emerging global public health problem. Transmission usually results from direct or indirect exposure to the urine or other body fluids of leptospiruric animals which may become a source of infection for human or other animals. Having a humid climate with plenty of annual rainfall, Guilan province is a suitable environment for maintaining Leptospira spp. Hence, early detection of Leptospira spp. in the host prompts control and protection, and the polymerase chain reaction (PCR) is a suitable method. The present report aimed to demonstrate the PCR analysis of bovine urine for detection of leptospiral DNA. A total of 98 urine samples were randomly collected from cattle bladder in Rasht abattoir of Iran and the presence of leptospiral DNA was assayed by PCR amplification of rrs (16S rRNA) gene and the results confirmed by nested PCR. Out of 98 urine samples in 42 samples leptospires DNA was identified with the frequency of 43%. The high presence of the organism in the urine of carriers is a serious threat to the dairy farms and to the public health which requires an effective control measure in the north provinces of Iran.

The production of monovalent and anti-idiotype antivenom against Mesobuthus eupeus (Scorpionida: Buthidae) venom in rabbits.

The antivenom production against poisonous creatures encounters a number of difficulties. Interestingly, according to the network theory the conventional antigens are not necessarily needed for producing antibodies against the venoms. In this investigation, the antivenom against Mesobuthus eupeus venom was produced based on the aforementioned theory. Polyclonal antibodies against M. eupeus venom were obtained from the immunized rabbits and the specific antibodies were isolated. After separation of Fab2, immunization process and production of the monovalent and anti-idiotype, these antivenoms were analyzed for the determination of their neutralizing power. The level of the produced antibodies in different stages of this study was also measured by ELISA assay. Four hundred and fifty micrograms of the venom can be neutralized by 4.2, 18 and 291 mg of monovalent, polyvalent and anti-idiotype antivenom, respectively. The ELISA results revealed that idiotypic antigens were six times more immunogenic than anti-idiotypes. The anti-idiotype antivenom can be produced on a large scale with minimum venom consumption. In addition, they are non-toxicant in immunized animals and can be used as a vaccine in people at the risk of scorpion stings.

Antimicrobial resistance profile and presence of class I integrongs among Salmonella enterica serovars isolated from human clinical specimens in Tehran, Iran.

BACKGROUND AND OBJECTIVES: Salmonella is one of the leading causes of food-borne diseases. Increasing occurrence of antimicrobial resistance, especially multidrug-resistance, in Salmonella serovars is a major public health problem worldwide. This study was carried out to detect class I integrons and antibiotic resistance profiles in clinical isolates of Salmonella serovars collected from seven hospitals in Tehran during November 2009 to June 2010. MATERIALS AND METHODS: Antibiotic susceptibility profile of 19 antibiotics against 58 Salmonella isolates commonly used in humans was determined using disk diffusion assay. Minimum inhibitory concentration against ceftriaxone and ciprofloxacin was studied. PCR assays were used to detect class I integrons. RESULTS: Among 58 Salmonella isolates, 72.4% were Salmonella enterica serovar Enteritidis, 8.7% were Salmonella enterica serovar Typhimurium and 18.9% were other serovars. Of the total 58 Salmonella serovars, 43 (74.1%) were multidrug-resistant and showed resistance to three or more antibiotic families. Class I integrons were identified in 38 (88.3%) MDR Salmonella isolates. Ciprofloxacin minimum inhibitory concentration ranged between 0.125-2 g/ml for four isolates and other four isolates exhibited resistance to ceftriaxone (MIC 64-256 g /ml). CONCLUSION: The high prevalence of class I integrons was seen in our MDR Salmonella isolates and class I integrons might play an important role in the dissemination of antimicrobial resistance determinants.

Identification of Helicobacter spp. in oral secretions vs. gastric mucosa of stray cats.

The definite mode of transmission of Helicobacter infection is largely unknown. This study was carried out primarily, to determine the existence of Helicobacter spp. in the oral secretions of stray cats as one of the possible routes of transmission and secondly, to evaluate the accordance between oral and gastric colonization of Helicobacter spp. in these cats. Forty-three adult stray cats were thus studied for the presence of Helicobacter species by quantitative rapid urease test (RUT), cytology and PCR. Helicobacter spp. were found in the oral secretions and gastric biopsies of 93% and 67.5% of the stray cats, respectively. There was not, however, any agreement observed between Helicobacter colonization at these two locations, at neither genus nor species level. These findings suggest that the oral cavity is routinely exposed to transient forms of bacteria and may temporarily harbor Helicobacter spp. Thus, oral cavity as a source of Helicobacter spp. may act as a reservoir for transmission and may not necessarily reflect the colonization status of the gastric mucosa.

Detection of Bartonella henselae in domestic cats' saliva.

BACKGROUND AND OBJECTIVES: Bartonella species are being recognized as increasingly important bacterial pathogens in veterinary and human medicine. These organisms can be transmitted by an arthropod vector or alternatively by animal scratches or bites. The objectives of this study were to identify contamination of cat's saliva and nail with B. henselae as a causative role to infect human in a sample of the cat population in Iran. MATERIALS AND METHODS: Blood, saliva and nail samples were collected from 140 domestic cats (stray and pet) from Tehran and Shahrekord and analyzed for the presence of B. henselae with cultural and polymerase chain reaction (PCR) methods and DNA sequencing. RESULTS: In this study B. henselae was detected in 10.9% of saliva samples (12/110) from pet cats. B. henselae was not detected in nail samples of pet cats (n=110), and in any feral cats' saliva and nail samples (n=30). CONCLUSION: Our data suggest that pet cats are more likely than stray cats to infect human with B. henselae after a bite and also stray cats can play a role as a reservoir for this bacteria. This is the first report that investigates the presence of B. henselae in cats oral cavity in Iran.

PCR-Restriction Fragment Length Polymorphism analysis of fljB gene in Salmonella enterica subspecies enterica serovar Typhimurium isolated from avians.

BACKGROUND AND OBJECTIVES: Economic constraint of diseases arising from Salmonella Typhimurium causes the study of this zoonotic organism more important. Most studies on identification and characterization of S. Typhimurium are conducted at DNA level. Flagellin genes (fliC and fljB genes encoding phase-1 and phase-2 flagella, respectively) are useful as a model system for studying genetic differentiation. The objectives of the present study were to identify the polymorphism of fljB among avians in different regions by the PCR-RFLP method. MATERIALS AND METHODS: Fifty-two S. Typhimurium isolates out of 1,870 intestine samples were identified using culture and serotyping as well as multiplex-PCR (broiler (n=13), layer (n=12), duck (n=5), goose (n=5), sparrow (n=8), canary (n=3), pigeon (n=5) and casco parrot (n=1)). Amplification of fljB gene was performed and amplified products subjected to restriction digestion with Hha I enzyme. RESULTS: Two RFLP patterns generated DNA fragments between approximately 50 to 800 bps. Pattern A was observed in 33 (63.46%) and pattern B in 19 (36.54%) of isolates. Salmonella Typhimurium recovered from 13 broilers (ten with pattern A and 3 with pattern B) and 8 sparrow (three with pattern A and 5 with pattern B) showed both A and B patterns. Twelve layers, 5 pigeons and 3 canaries showed pattern A and 5 ducks, 5 geese and one casco parrot showed pattern B. None of these patterns was allotted for a special region. CONCLUSION: The results of the present study showed that fljB gene is highly conserved among avians in different geographical regions, suggesting not only the importance of fljB gene in survival of organism in different environmental conditions but also the relation between proteins encoded by fljB gene and serotyping scheme.