سید سعید اشراقی

Meat can be contaminated by Leptospira species. This bacterial pathogen causes severe leptospirosis disease in humans and animals. The major aims of this study were to assess seroepidemiological prevalence of leptospirosis in employees of a slaughterhouse in Guilan Province, Iran, using microscopic agglutination test and further investigate the positive samples using nested polymerase chain reaction method.

In this study, 150 employees of a slaughterhouse in Guilan Province, Iran, were participated after completing written consents and personal questionnaires. This sample size was calculated based on the mean prevalence of the pathogen in the region. After assessing sera of the participants for Leptospira antibody using microscopic agglutination test, urine samples were collected from the positive participant for further assessments using nested polymerase chain reaction.

Based on the results, microscopic agglutination test was positive for 10.7% of the participants. However, Nested-PCR was negative for the positive microscopic agglutination tests on sera collected from the participants with antibodies against Leptospira antigens. The current results demonstrate that Leptospira can occur in asymptomatic humans in slaughterhouses and highlight the high potential of the disease transmission to humans in the province. Therefore, further extended control and prevention measures for slaughterhouse workers are recommended to guarantee the food safety. Conflict of interest: The authors declare no conflict of interest.

This study aimed to investigate the antimicrobial properties of metabolites extracted from cellulose microbiomes to better understand their potential as a source of new antimicrobial agents.

In this observational-analytical study, 50 soil samples were collected from different regions of Tehran province. After culturing, suspicious colonies were phenotypically and biochemically tested, and molecular identification was performed by amplifying the 16S rRNA gene. Primary screening of metabolite production with antibacterial and antifungal effects was done using the Cross-Streak Method. The antimicrobial effect of the extracted metabolite was measured using the well diffusion method and the minimum concentration of growth inhibition. Finally, the chemical composition and potential metabolite substance were determined through high-performance liquid chromatography and mass spectrometry.

Five Cellulosimicrobium isolates were identified using biochemical methods and molecular identity verification. Among the five isolates suspected to be Cellulosimicrobium, strong antibacterial activity was observed in one isolate during the screening stage. Cellulosimicrobium had a strong effect on Escherichia coli and methicillin-resistant Staphylococcus aureus, but no antifungal effect was observed. The structure of the desired metabolite with the formula C14H24N2O7 was identified through HPLC and Mass chromatography analysis.

These findings suggest that Cellulosimicrobium is a promising source for the discovery and development of new antimicrobial agents.

Nocardia asteroides complex is the most common cause of infectious diseases due to nocardiosis. Interspecies differentiation of Nocardia genera is essential for prognosis and timely proper treatment, as well as for epidemiological studies. Since each genus has its own antibiotic resistance, precise careful diagnosis is of prime importance. As compared to biochemical and phenotypic methods, the efficacy of molecular methods for fast and accurate identification of Nocardia species has been proven. The aim of this study was to detect for the first time Nocardia asteroides complex in clinical isolates using real time polymerase chain reaction (Real-Time PCR).

Out of the 25 clinical isolates suspected to be Nocardia asteroides genus 10 were identified as Nocardia asteroids complex by biochemical and phenotypic methods, followed by genomic DNA extraction of the suspicious isolates. Nocardia asteroides complex positive controls were prepared using standard strains. Real-time PCR was conducted on all the 10 suspicious isolates. The final real-time PCR samples were sent for sequencing to verify the identified species.

Based on sequencing results 3 of 10 clinical isolates suspected to be identified as Nocardia asteroides complex were confirmed as belonging to the Nocardia asteroids complex genera ─ Nocardia asteroids, Nocardia farcinica, and Nocardia nova.

This study shows that, as compared to biochemical and phenotypic methods, real-time polymerase chain reaction is faster and more specific, and is considered as an efficient method, for Nocardia interspecies identification and differentiation.

Nocardia is a germ-positive filamentous bacterium with relative acid-fast properties that ubiquitously exists as an environmental saprophyte. Nocardiosis is usually characterized as an acute or chronic illness associated with pus or granulomatosis, which can cause an aggressive disease both in healthy people and immunosuppressive patients. The aim of this study was to identify the biodiversity of Nocardia species isolated from Tehran hospitals via phenotypic and PCR molecular approaches.

200 samples were collected from Tehran hospitals. After being separated by paraffin baiting technique, the colonies were evaluated for their growth abilities in liquid lysozyme and at 45°C and based on other biochemical tests via macroscopic examinations and then microscopic gram and relative acid-fast staining practices. Ultimately, we designed a genus-specific primer set and performed the PCR reaction to compare both results.

From the 200 samples, 30 samples were identified as positive based on the culture and biochemical tests and molecular method.

Considering the species diversity of Nocardia genus and the existence of different conditions for performing phenotypic and biochemical tests, it is very probable that another genus relevant to the actinomycete family be mistakenly identified as Nocardia. Thus, molecular methods can provide confirmation of the phenotypic approach.

Nocardiosis is a rare and potentially life-threatening infection caused by several species of the Nocardia genus. The objective of this study was to develop and evaluate a rapid and new method to clinically identify relevant Nocardia species. Rapid and accurate diagnosis of Nocardia species is essential for the treatment of severe infections and prevention of cerebral abscess.

One hundred and eighty patients, 103 (57.22%) male and 77 (42.78%) female, with severe symptomatic pulmonary infection were studied in the course of a 12-month period in Dr. Shariati Teaching Hospital affiliated to Tehran University of Medical Sciences in 2010. The specimens were cultured and identified using microbiological and biochemical tests. Polymerase chain reaction (PCR) was used to directly identify the organism in the broncoalveolar lavage samples collected from the patients. NG1 and NG2 primers were used to amplify a Nocardia genus-specific 598-bp fragment of 16S rRNA.

Nineteen samples (10.56%) were positive with PCR and 5 samples (2.78%) with conventional methods. All samples with positive cultures were also positive by PCR.

The results of this study showed that PCR has a high sensitivity and accuracy for the detection of Nocardia compared with culture and biochemical tests. Considering the rapidity, precision, high sensitivity and specificity of molecular techniques, use of these techniques is suggested in conjunction with conventional methods for the detection of Nocardia phenotypes in clinical laboratories and research centers.

Salmonellosis is a bacterial gasteroenteritis caused by different serovars of Salmonella. In the recent years, Salmonella enterica subspecies. Enterica serovar enteritidis is a major cause of gastroenteritis and food poisoning in the worldwide. Different genus of salmonella is increasingly being resistant to common antibiotics. The aim of this study was to determine the frequency and the antibiotic resistance patterns of Salmonella enterica isolated from medical health centers in Tehran. In this descriptive cross- sectional study from April to December 2008, 1950 fecal specimens from children