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The genus Nocardia, are partially acid-fast, Gram-positive and catalase-positive bacteria that are not normal flora in human and animals. Accurate identification of Nocardia species is important for treatment planning and epidemiology research. To date, the molecular methods such as polymerase chain reaction-restriction fragment length polymorphism and polymerase chain reaction sequencing are used for accurate and rapid identification of Nocardia species.

Nocardia spp are aerobic, Gram positive, weakly acid fast and non-motile bacteria. The bacteria invade the human body from the environment via trauma or the respiratory tract and cause cutaneous, pulmonary, and systemic disorder. So far, number of isolation techniques are described including: 1. paraffin baiting technique, 2. humic acid-vitamin agar, and 3. selective buffered charcoal-yeast extract medium e. g.

Background and objectives: Timely diagnosis of leptospirosis is essential for an effective treatment. Large diversity of clinical symptoms has led leptospirosis diagnosis difficult. Researchers have conducted many tests with wide-range of sensitivity and specificity to achieve novel diagnostic procedures which have higher sensitivity and specificity compared with previous tests and which are more reliable and available to public laboratories. This study aimed to introduce Lsa63 and LipL32 proteins-based ELISA tests with more sensitivity, specificity, accuracy and convenience for public laboratories. Materials and Methods: Recombinant forms of Lsa63 and LipL32 proteins were first generated. After coating these proteins, IgM and IgG ELISA tests were performed. 220 patients with suspicion of leptospirosis infection were selected for serum collection. The sera tests were carried out using MAT, IgM and IgG ELISA tests. In order to assess the performance of ELISA, the results of this test were compared with MAT. Results: 30% of serum samples (n=65) in MAT were positive for leptospirosis infection, while ELISA tests including rLipL32- rLsa63-IgM and rLipL32-rLsa63-IgG showed 40.45% (n=89) and 38.63% (n=80) positive reaction respectively. Conclusion: Our results demonstrated that new ELISA tests based on mixing LipL32 and Lsa63 proteins, a novel mixture of recombinant antigens, are valuable to detect specific antibodies against pathogenic Leptospira in human serum and could be considered as helpful techniques in leptospirosis diagnosis.

Background: Nocardia are Gram-positive, aerobic and partially acid-fast and cause dangerous infectious disease, nocardiosis, by entering the respiratory tract or damaged skin. In this study, we used various biochemical tests for identificating Nocardia species in soil samples of the city of Tehran, Iran. Methods: After isolation of Nocardia using paraffin baiting method, for detection and identification of various species, some phenotypic tests including growth in lysozyme broth, hydrolysis of amino acids such as hypoxanthine, xanthine, tyrosine, casein, gelatin and urea, production of nitrate reductase, growth at 35 °C and 45 °C, and utilization of some carbohydrates were used. Findings: The analysis of phenotypic tests presented that 12 isolates of Nocardia asteroides (63.15%), 5 isolates of Nocardia cyriacigeorgica (26.31%), and 1 isolate of Nocardia otitidiscaviarum (5.26%) were identified. Only 1 isolate (5.26%) remained undetected after phenotypic tests. Conclusion: In this study, several Nocardia species isolated from the soil samples of Tehran which were phenotypically similar to the well-known species. However, further identification tests are required to confirm the heterogeneity of the isolates and to identify the exact phenotype and genotype of the Nocardia species.

Background: 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. Methods: 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.Results: 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.Conclusion: 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.

Background: Nocardia species are Gram-positive, partially acid fast, non-motile, catalase positive, aerobic and saprophytic actinomycetes found all around the world. They invade the human body from the environment via trauma and respiratory tract and cause cutaneous, pulmonary and systemic diseases. They are able to grow in various media.The organisms opportunistically infect both immunocompromised and immunocompetent individuals. Behcet's disease is an autoimmune disease and immunocompromised patient which may suitable host for Nocardia bacterium. The present study is the first case report of isolation of Nocardia from the thigh abscess in a patient with behcet’s disease from Iran.Case Presentation: A 39-year-old man with Behcet’s disease in August 2011 was admitted to Shariati hospital Tehran, with swelling and pain in the left flank and left thigh. Microscopic identification from direct microbiological slide of thigh abscess discharge demonstrated number of lymphocytes, neutrophils and macrophages foamy and white blood cells together with filamentous bacteria. Further microbiological characterization using phenotypic and antibiogram tests with disk diffusion method, demonstrated that the isolated bacterium is Nocardia asteroides complex. The bacteria were sensitive to ampicillin, vancomycin, ceftriaxone, amikacin and cotrimoxazole but it was resistant to clindamycin, erythromycin, penicillin G, cephalothin and gentamicin. The patient was treated with cotrimoxazole.Conclusion: Because of the high incidence and high mortality of Nocardia infection in immunocompromised cases, rapid detection and timely treatment for these patients is necessary.

Background Re-emergence of pertussis has been reported in Iran despite a high rate of vaccination coverage. Low efficacy of the vaccine might be due to the genetic divergence between clinical versus vaccine strains. In the current study, the genetic profiles of clinical isolates and vaccine strains of Bordetella pertussis (B. pertussis) were assessed by using Pulsed Field Gel Electrophoresis (PFGE). Methods Following phenotypic and molecular identification of isolates, XbaI-digested genomic DNA of 5 clinical isolates, 2 vaccine strains and a Tohama I strain were analyzed by PFGE along with B. parapertussis as a control. Results Seven distinct PFGE profiles were found among all examined isolates/strains. In 5 clinical isolates, 4 profiles were identified whereas the vaccine strains displayed 2 distinct profiles. The reference strain, Tohama I had a distinct profile. Vaccine and clinical profiles had low similarity, with relatedness of approximately 40%. Conclusion The genetic profiles of B. pertussis were different between circulating isolates and vaccine strains used in the national vaccination programs. Since new genetic profiles of B. pertussis can be disseminated periodically, the profiles of isolates circulating in the population should be monitored over the course of the re-emergence.