Background & Objectives: Clostridium difficile as an etiologic agent of pseudomembraneous colitis and major cause of nosocomial antibiotic-associated diarrhoea is typed by phenotypic and molecular methods. The aim of this study was to investigate the distribution of ribotypes of the organism in the given region and time.

  Methods: In this study 18 strains isolated from patients from different hospital wards of Poland in 2002 and 2003, were examined and identified by susceptibility to vancomycin and metronidazole. The samples were re-identified using UV and latex agglutination to ensure the existence of A and B toxins. DNA was extracted and after amplification by PCR and electrophoresis, the strains were ribotyped.

  Results : The findings showed that all the strains were susceptible to vancomycin and metronidazole and all the colonies showed greenish-yellow fluorescence under UV. Moreover, all the strains were positive in terms of latex agglutination. Seven strains were toxin A positive and all were toxin B positive except one strain. In molecular ribotyping it was found out that these strains belonged to seven ribotypes, namely 12, 14, 17, 18, 29, 70 and 90 most of which were ribotype 17 (61%).

  Conclusion: Our observations imply that in each area a particular ribotype of c.difficile is of higher prevalence and ribotyping of this clostridium is necessary for epidemiologic studies. Identification and PCR-ribotyping of common strains of this organism in Iran are recommended for epidemiologic follow-ups.

  Background & Objectives: Cryptosporidium is a coccidian protozoan parasite. This organism is one of the main causes of severe, long-time and life-threatening diarrhea in immunocompromised persons. It is also among the most prevalent diarrheal agents in children. Cryptosporidial epidemics occur after consumption of water which is contaminated by oosit species of cryptosporidium. Water is usually contaminated by animal feces or by drainage of waste water into drinking water resources.

  Methods: In this study, from ten regions 200 water samples were collected, filtered by 1.2 micron papers and then positive samples were identified in terms of cryptosporidium using PCR method. Finally the related species were detected by RFLP method.

  Results: Nested-PCR showed 8 samples were positive for cryptosporidium that according to RFLP of PCR products 5 samples belonged to cryptosporidium andersony, 2 samples belonged to cryptosporidium parvum bovine genotype and 1 sample belonged to cryptosporidium pig genotype.

  Conclusion: Since Cryptoridium andersony and cryptosporidium parvum bovine genotype are the common species in animals and cryptospovidium swiss is seen in wild animals (pigs and boars), it so we conclude that animal reservoirs have the main role in the contamination of related water resources in this region.

  Background & Objectives : Panel-reactive antibody (PRA) is a routine test to evaluate for sensitized human leukocyte antigens (HLA) before kidney transplantation. The present study evaluates the correlation of renin-angiotensin system (RAS) polymorphisms with the level of PRA in renal transplant candidates.

  Methods: This study included 108 renal transplant candidates. The current patients sera were screened by standard complement-dependent microlymphocytotoxicity technique. RAS polymorphisms were determined by polymerase chain reaction. PRA<10, 10-29, 30-49, and ≥50 considered as negative, mild, moderate, and highly positive PRA, respectively.

  Results: Twelve (11.1%) patients had positive PRA, among them 10 (83.3%) had mild and 2 (16.7%) of them had moderate PRA levels we had no highly positive PRA. Ninety-six of cases (88.9%) were negative for PRA. There was no significant correlation between discrete RAS polymorphisms (alone or together) and the degree of panel antibody reactivity (P>0.05).

 Conclusion: We suggest that none of the RAS polymorphisms could predict the positivity degree of PRA level.

  Background & Objective: Mycobacterium leprae is the cause for leprosy which is a contagious disease in many developing countries. These diseases have always been a dreadful one for its unpleasant clinical symptoms and the disabilities it causes. It has the most prolonged cell division time of all bacteria (12-14 days). Its incubation period is long (3-5 years) even 40 years has been reported. The complications which it leaves are irreversible and it bears a heavy socio-mental burden on the individual and the society. WHO has listed 91 countries with leprosy. The goal of the present study was the early diagnosis of the disease before the emergence of unpleasant clinical symptoms and popularizing molecular method of PCR in place of the conventional method of slit skin smear which is not a precise or reliable method.

  Methods: In this study 40 slit skin smear and the same number of skin biopsies were taken from patients referring Bababaghi Hospital and samples from ear lobes and eyebrows were taken. Slit skin smears were stained with Zeihl-Neelsen method and examine microscopically. At the same timy biopsy specimens were extracted.

 Results: Of 40 samples, three slit-skin specimens (7.5%) had positive smear result, while 14 (35%) biopsies had PCR positive result. The rest (11 cases) probably had TT or borderline forms of BB, BT, BL).

 Conclusion: The results showed that SSS is not a precise and reliable method for diagnosing leprosy especially in TT form which is always negative direct smear. Also direct smear method and clinical symptoms are not accurate or reliable methods in estimating the rate of disease prevalence.

  Background & Objective: Tuberculosis is more prevalent in developing countries and death from tuberculosis meningitis is strongly associated with delays in diagnosis and treatment. Polymerase chain reaction (PCR) has been incorporated as a diagnostic tool for the diagnosis of tuberculosis. The rapid results and greater sensitivity compared to traditional microbiological methods makes PCR a suitable technique in tuberculosis, especially in tuberculosis meningitis, when diagnosis is difficult or when rapid diagnosis is needed. However, the possibility of false positive and false negative results must be considered. The aim of this study was to compare the conventional bacteriology (culture Ziehl- Neelsen staining) with polymerase chain reaction (PCR) technique for rapid diagnosis of tuberculosis meningitis.

 Methods: This study included 25 clinically diagnosed patients that were suspected to have tuberculosis meningitis and 10 other bacterial or viral meningitis patients were investigated. DNA was extracted from CSF and the NESTED PCR using specific primers were done.

 Results: In 25 samples, Mycobacterium tuberculosis DNA was detected in 9 (36%) by PCR, 2(8%) and 1(4%) with culture and direct smear was obtained, respectively. whereas no DNA bands were detected in patient with the other 10 meningitis. The entire procedure was repeated and the same result was obtained.

 Conclusion: The findings of this study indicated that PCR is a powerful method for rapid and sensitive diagnosis of tuberculosis meningitis. In a way that it decreases obtaining the results from several weeks in bacteriological methods to one to two days, especially in smear negative patients. This is very important in tuberculosis meningitis because it is a medical urgency and needs rapid diagnosis and early treatment.

  Background and objectives: Leptospirosis is a very common zoonosis in the world. Early diagnosis of leptospirosis is critical because just early treatment will be effective. It's culture is very slow and serological assays are not applicable because of lack of antibodies in the first week of the disease, therefore PCR is the only option for the early diagnosis. In this study, sensitivity and accuracy of a non-quantitative conventional PCR for diagnosis of leptospirose in first week sera of patients, is evaluated

  Methods : Seventy first week sera sample of patients with clinical diagnosis of leptospirosis which were negative in MAT but positive for the second time after one weeks (seroconversion) were selected and studied.

  Results : We observed twenty four positive sera in PCR test. Sensitivity of the test was 74.5% and accuracy was 100 bacteria /ml.

  Conclusion : Result of our study shows that PCR is the only choice for the early diagnosis of Leptospirosis while other assays are not applicable but its sensitivity is low.

  Background & Objectives: Leishmania infantum is the causative agent of visceral leishmaniasis (VL). Based on isoenzyme typing of a few isolates from patients and domestic dogs, this parasite was considered to predominate in the Kaleybar focus of VL in northwest Iran. There is no report of sandfly infections in this region so this study was aimed to investigate the infection of the sandflies in the field.

  Methods: Sandflies were sampled using sticky paper and CDC traps. Morphological identifications were carried out based on characters of the head and abdominal terminalia. DNA extracted from sandflies abdomens and thoraxes. ITS-rDNA gene of parasite was detected and identified as Leishmania after sequencing.

  Results: Out of 146 sandflies 9 were found to be infected with Leishmania. For first time, three Leishmania species (L. infantum, L. tropica and L. major) were identified in sandflies simultaneously in the region. Among the all sandflies only one Phlebotomus perfiliewi (vector of VL) was found to be infected with L. infantum. All Isolates were confirmed by sequencing of ITS-rDNA gene.

  Conclusion: However, Leishmania tropica and L. major were found more than L. infantum in sandflies in Kaleybar but it could not conclude that these two species of Leishmania are causative agents of VL. Because many criteria should be considered to incriminate an agent or vector of the disease.

  Background & objectives : Amikacin is one of the key second-line drugs for treatment of tuberculosis. Mutations at the codons 1400, 1401and1483 of the 16srRNA gene are associated with resistance to amikacin. The purpose of this study was to detect these mutations using PCR-RFLP method in multi-drug resistant (MDR) strains of Mycobacterium tuberculosis showing resistance to amikacin.

  Methods : Susceptibility of strains (n=100) against first and second–line anti-tuberculosis drugs was performed by proportional method. Based on antimicrobial resistance pattern 97 strains were analyzed by PCR-RFLP method. rrs1096 and rrs1539 primers were used to amplify a 460bp region of the rrs gene. Then, the PCR products were digested using Tai 1 and Dde1 restriction enzymes. The results were analyzed by the SPSS software using Chi-square test.

  Results : Based on results from proportional method, 63 strains (64.9%) were MDR (Multiple Drug Resistant), 26 (26.8%) and 8 (8.2%) strains were susceptible and non-MDR, respectively. Also, 13.4% and 6.1% of the strains were XDR (Extensively Drug Resistant) and TDR ( Totally drug resistant ) respectively. Using PCR-RFLP method, 7 (7.2%) strains were resistant and 90 (92.7%) strains were susceptible to amikacin respectively. Moreover, we found that the mutation at the codon 1400 was the most frequent mutations responsible for resistance to amikacin.

  Conclusion : The PCR-RFLP method can be used as a supplemental method to detect resistance to amikacin however to increase our knowledge, mutatuions in several number of codons in rrs gene need to be studied.