[Isolation and identification of Nocardia asteroids complex isolated from thigh abscess in a patient with Behcet's syndrome: the first report from Iran]

Nocardia species are Gram-positive, partially acid fast, non-motile, cata-lase 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 immuno-competent 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. 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. Because of the high incidence and high mortality of Nocardia infection in immunocompromised cases, rapid detection and timely treatment for these patients is necessary

Molecular typing of nocardia species

Identification of clinically significant Nocardia species is essential for the definitive diagnosis, predict antimicrobial susceptibility, epidemiological purposes, and for an effective treatment. Conventional identification of Nocardia species in routine medical laboratories which is based on phenotypic [cellular morphology, colonial characteristics], biochemical and enzymatic profiles, and chemotaxonomic characteristics is often laborious, and timeconsuming. The procedure requires expertise, and newer species can be difficult to differentiate with accuracy from other related species. Alternative methods of identification, such as high performance liquid chromatography [HPLC] and molecular biology techniques allow a better characterization of species. The taxonomy of the genus Nocardia has been dramatically been revised during the last decade and more than 30 valid human clinical significance species of Nocardia have been reported. The use of molecular approaches, including 16S rRNA gene sequencing, restriction fragment length polymorphism [RFLP] or PCR restriction endonuclease analysis has been the focus of recent investigations to distinguish the isolates of Nocardia from other actinomycetes genera. The methods have revolutionized the characterization of the Nocardiae by providing rapid, sensitive, and accurate identification procedures. The present review describes the currently known medically important pathogenic species of Nocardia.

[ identification of nocardia in BAL specimens of bronchoscopic patients by using classical and molecular methods]

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

Molecular analysis of van HAX element in vancomycin resistant enterococci isolated from hospitalized patients in Tehran

Vancomycin [glycopeptide]-resistant enterococci [VRE or GRE] can cause serious problems for hospitalized patients due to the limited options for treatment of VRE infections. As infection with VRE increases in hospitals, further knowledge about vancomycin resistant genes is needed. Isolates of Enterococcus spp. were collected from hospitalized patients in Tehran [Iran] during 2006. Detailed molecular analysis was performed for vancomycin resistance genotype and vanHAX using conventional PCR and PCR- RFLP [restriction fragment length polymorphism], respectively. out of 830 enterococci spp., 48 VRE isolates [5.8%] were obtained. All of VRE isolates carried vanA gene. DdeI digestion of vanHAX element showed the presence of point mutation at 8234 position. This study indicates that vanA is a predominant genotype in Iranian isolates. In addition, PCR-RFLP analysis revealed the presence of two types of vanHAX element in vanA harboring transposons