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Background and Objective: Leptospirosis is a worldwide zoonosis that is more common in tropical and semitropical regions and in flat area of Guilan province, nothern Iran, caused by pathogenic leptospires.Serotyping by MAT is complicated, expensive and time cosuming. Molecular typing can be useful alternative. This study was performed to identify the typing of endemic pathogenic leptospires, isolated in Guilan province, by PCR-RFLP. Materials and Methods: In this discriptive study, specimens were taken from patients in Razi hospital, Rasht, Iran ,from April to August 2008. DNA of all positive cultures were extracted by Phenol-Chloroform method. PCR was performed by using two primer sets: B64-I, B64-II for Kirschnery serovars whose PCR product were digested by HinfI for RFLP, and G1,G2 for all other species whose PCR products were digested by DdeI. Band profiles of digested PCR products were compared to band profiles of standard servers to determine species and subspecies. Results: 65 of totally 107 blood cultures were positive. 56 Samples were amplified by G1, G2 included Interrogans and Borgpeterseni and 9 samples were amplified by B64-I, B64-II including Kirschneri species. Conclusion: This study showed that the majority of leptospires species are Interrogans and Borgpeterseni. Regarding to several existing problems in Seortyping of leptospires by MAT, PCR-RFLP can be useful for identifying isolating and studying the serovars in different certain species. It seems that PCR-RFLP can be performable for clinical samples for both early diagnosis and characterization.

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Background and Objective: Helicobacter pylori (H.pylori) with positive Cytotoxin associated Gene A (CagA) have higher potential for pathogenesis. Cytotoxin associated Gene A (CagA) accelerate the pathogenecity of bacteria due to cytotoxin production stimulation. The aim of this study was to determine the prevalence of the anti-CagA antibody among H. pylori infected persons in Golestan province-North of Iran. Materials and Methods: This descriptive study was carried out on 676 H. pylori positive subjects in Golestan province, northern Iran during 2008. Anti CagA antibody were determined in H.pylori positive subjects. Data analyzed by SPSS-16 software and chi-square test. Results: Prevalence of anti CagA in Helicobacter pylori infected cases was 57.7% (390 cases: 179 males and 211 females) (95% CI: 53.9-61.4). According to age the highest and lowest cases of anti CagA antibody were seen in, 15-24 (63.4%) and under 5 years old (26.3%). The level of anti CagA antibody in Sistanian ethnicity group (67.2%) was more than other ethnic group. Anti CagA antibody in Rural area was more than urban regions. Sero prevalence of anti CagA antibody was highest in Minudasht twon (78%), located in East of province in comparison with Bandar Gaz (44%) in west of province. Conclusion: This study showed the prevalence of CagA positive Helicobacter pylori strains in this region is similar to other regions of Iran, Asia and Europe and higher than African population.

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Background and Objective: The incidence of infections is one of the most disturbing problems in the management of patients with systemic lupus erythematosus (SLE). The aim of this study was to describe the role of tuberculosis (TB) as a cause of fever in SLE patients. Materials and Methods: In this descriptive study 103 SLE patients enrolled in Ahvaz, South-West of Iran during 2000 - 06. Patients were diagnosed according to American College of Rheumatology criteria (at least 4 of 11 criteria). Diagnosis of tuberculosis was based on Iranian National Program against TB criteria. The infection free patients were given corticosteroid therapy. Results: In this study 20 patients did not follow the complete cycle and finally 83 patients were established as sample population of this study. Mean age of patients was 22.2±10 years, female to male ratio was 9.2:1, mean duration of treatment was12±3.2 months and mean of daily dose of prednisolone was 28.2±13 mg.From total of patients, 8 (9.6%) had active tuberculosis. five patients had pulmonary and three with other type of TB, respectively. One of the above eight patients eventually died due to SLE/TB. Conclusion: Tuberculosis is one of the important causes of fever among patients with SLE under treatment of corticosteroid. In approaching febrile SLE patient TB should always be considered as a treat.

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Background and Objective: The Clostridium botulinum is one of the most important causative of food poisoning. Spores of Clostridium botulinum spread out in the soil, the sea sediments, the marine environments and the marine animals. In recent years use of the marine food products like as fish and cultured fish are elevated. The aim of this study was done to compare between processing and non processing fish infected by predominant type of Clostridium botulinum.

Materials and Methods: This descriptive study was done on the 146 samples of fish in two species of processed and non prosecced that collected from Gilan province in Iran during 2008. These samples included the Liza auratus Fish (45 processed fish and 28 non processed fish) and the Salmo Trutta caspius Fish (34 processing fish and 39 non processing fish). The samples examined according to the APHA2000 and FDA2003 protocols. Data Analyzed with SPSS-13 and Chi-Square test.

Results: 16 (11%) of samples (13% of the processed fish and 7.5% of non processed fish) were confirmed that infected by Clostridium botulinum. Also the dominant type of exotoxin was Type E. The Type E exotoxin was determined from 11 of the samples (6 processed fish and 5 non processed fish).

Conclusion: This study showed that fish are infected by Clostridium botulinum special the type E. also use of fish in bad preparation (half cooking and add material in its stomach) may cause the food poisoning.

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Background and Objective: Pseudomonas aeruginosa is one of the important causes of nosocomial infections. Extended spectrum-beta Lactamases (ESBLs) and Metallo-beta Lactamase (MBL) producing strains have become resistant against a wide range of antibiotics. The aim of this study was to determine the effect of Methanol extract of Camellia Sinensis on Pseudomonas aeruginosa producing ESBL isolated from burnt wounds of patients.

Materials and Methods: This descriptive study was done on burnt wounds of 245 hospitalaized patients in Shafa hospital, Kerman, Iran during 2006-07. ESBLs producing strains were detected by phenotypic confirmatory test and also E-test strips were used for MBL detection. P.aeruginosa MIC was determined for Cefotaxime, Ceftazidime, Azteronam, Imipenem, Meropenem and methanol extracts of plant Camellia Sinensis prepared by Maceration method.

Results: 120 of burnt wound infected with P.aeruginosa, out of them 41 isolates contained ESBL while lacked MBL. 60% of isolates were resistant to Cefotaxime, 66% to Ceftazidime, 42% to Azteronam, 3% to Imipenem and 5% to Meropenem. Among the extracts, green Tea had the highest antibacterial effect on standard strains and P.aeruginosa producing ESBLs in 1.25mg/ml concentration.

Conclusion: This study showed that methanolic extract of green tea has higher antibacterial effect aginst β-lactamase P.aeruginosa strains than Cefotaxime and Ceftazidime.

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Background and Objective: Considering the significant incidence of nosocomial infections in hospitalized patients, this study was done to determine the prevalence of Staphylococcus aureus strains isolated from wound infection and drug sensitivity pattern, Tehran-Iran. Materials and Methods: In this descriptive study, Staphylococcus aureus isolated and identified according to standard procedures from the wound infections of 614 patients referred to Baqiyatallah hospital, Tehran-Iran during 2006-07. The samples were examined and antibiogram was performed by disc diffusion method on Mueller Hinton agar with 12 antibiotics. Results: 100 (16.28%) of wound infection of Staphylococcus aureus was isolated from 614 patients. The infection rate in men was twice compared to women. The highest rate 29 (29%) was observed in people aged 40 to 60 group. Also specimen's patients with immunosuppressive diseases (28 cases), surgical site infection (16 cases) and normal wounds (13 cases) were considered to be most prevalent isolates. Antibiotic sensitivity testing revealed that 96 (96%) of isolates were sensitive to vancomycin, 95 (95%) and 92 (92%) were resistant to penicillin and cotrimoxazole, respectively. Our result showed that 43% of strains were resistant at 11 antibiotics. Conclusion: This study showed that the prevalence of Staphylococcus aureus was 16.28% of samples, with 43% antibiotic resistance. The highest sensitivity was toward to vancomycin.

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Background and Objective: Pollution due to the heavy metals is a problem that may have negative consequences on the hydrosphere. Identification of microorganisms resistant to heavy metals plays an important role in relation to environmental pollution bioremediation. This study was done to assess the antibiotic resistance in isolated bacteria from urban sewage and copper smeltery industrial wastewater. Materials and Methods: This laboratory study was done on the wastewater samples from urban sewage and copper smeltery in Isfahan-Iran, during 2011-12. Heavy metal resistant microorganisms were isolated and enumerated after serial dilution and culturing on PHG agar plates supplemented with 0.5 mM of each heavy metal. The pattern of resistance was assigned by Minimum Inhibitory Concentration (MIC). Antibiotic resistance toward following medicines Ofloxacine, Penicilline, Sulfometoxasole, Lincomycin, Kanamycin, Streptomycin, Clindamycin, Vancomycin, Cefradin and Neomycin were subsequently investigated. Results: The greatest resistance in isolated bacteria has been related to the Ni (MIC: 24 mM) that’s related to the genus of Klebsiella and its minimum MIC is 2mM that’s of Acinetobacter lwoffi, Providencia stuartii, Branhamella. The minimum degree of resistance is related to Cu. Its Maximum MIC related to this metal in swage is 2 mM that’s of Klebsiella pneumoniae and its minimum degree of resistance in copper smeltery effluent is arranged as 1mM related to genus of Pseudomonas alkaligenes. In examining multi metal resistance pattern, the greatest resistance with 8 mM MIC has been related to the Cd, that’s of Ni resistant Moraxella osloensis in Copper smeltery effluent. The highest portion of isolated bacteria were resistant to Pb (P<0.05). The highest resistance of refirary wastewater was to Ni (MIC: 2 mM), which belong to Klebsiella (P<0.05). The lowest belong to Acine to bacter Lwoffi providencia Stuartii, Branhamella (MIC: 2mM) (P<0.05). In urban sewage: the highest resistance belong to copper, which was seen in Klebsiella Pneumoniae (MIC: 2mM). In Antibiogram tests of Klebsiella, Moraxella and Escherichia, it was demonstrated that the metal resistant bacteria were also resistant toward Lincomycin, Kanamycin, Streptomycin, Clindamycin, Vancomycin, Cefradin and Neomycin, as well. Conclusion: Increasing heavy metal resistance in the environment leads to increased antibiotic resistance toward microorganisms.

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Background and Objective: Nanosilver particles are one of the functional nanotechnology filed. These nanoparticles have antibacterial characteritics. Combination therapy is one of new and specific therapeutic regiment in medicine. Eucalyptus plant is useful in growth inhibition of bacteria. This study was done to evaluate the inhibitory effect of alcoholic eucalyptus extract with nanosilver on E.coli growth. Materials and Methods: In this laboratory study, E.coli was cultured in nutrient agar medium. Primarily 50 l of bacteria was inocolulated in each plate, antibiograms disc contiminated with 3.1, 6.25, 12.5, 25 and 50 ppm concentration of nanosilver accompanied with 100% of etanolic extract of eucalyptus were placed in each plate subsequently. Diameter of inhibitory zone were evaluated following 24, 48, 72 hrs in 6th and 8th days. Data were analyzed using SPSS-15, ANOVA and Tukey tests. Results: After six days, inhibitory growth zone diameter of E.coli was 0.5 mm. This diameter in experimental group with 3.1, 6.25, 12.5, 25 and 50 ppm of nanosilver in combination with etanolic extract of eucalyptus were 0.55, 0.58, 0.82, 0.83 and 1.02 mm. Inhibitory growth zone in group of 12.5, 25 and 50 ppm of nanosilver was significant in compared to the control (P<0.05). Conclusion: The most proper time of inhibitory effect on E.coli growth is six day after treatment in combination of 50 ppm nanosilver particles with extract of eucalyptus.

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Background and Objective: Klebsiella species are gram-negative bacteria with positive voges proskauer (VP) reaction. Klebsiella species are found as commensal in human digestive and respiratory system. This group of organisms can create a serious health hazards in hospitalized patients, and their ability to drug resistance is a major health problems. This study was done to evaluate the efficacy of Ciprofloxacin, Ceftizoxims and Carbenicillin on Klebsiella species isolated from hospital specimens. Materials and Methods: In this laboratory study, 1200 clinical samples were isolated from patients in Imam Khomeini hospital, Tehran, Iran. The identification Klebsiella species were carried out according to conventional biochemical tests. The minimum inhibitory concentration (MIC) of carbenicillin, ceftizoxime, and ciprofloxacin antibiotics were determined using Macrodilution broth test. Results: Out of 1200 isolated samples, 25% were identified as Klebsiella species. 73% of identified Klebsiella were obtained from urine samples. Klebsiella.peumoniae with rate of 94% was the most abundant among other species. The results of MIC and minimum bactericidal concentration by using standard microdilution method showed drug resistance range of 16-1024 μg/ml, 4-256 μg/ml and 0.25-16 μg/ml for carbenicillin, ceftizoxime, and ciprofloxacin, respectivley. In general, 94%, 6% and 1% of species were resistance to carbenicillin, ceftizoxime and ciprofloxacin, respectively. Conclusion: Ciprofloxacin and Ceftizoxime are suitable for the treatment of infections due to Klebsiella species.

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Background and Objective: Ferula gummosa Boiss. (Barije.) contain medical and antimicrobial properties. This study was done to determine the effect of aqueous and alcoholic extracts of roots of Ferula gummosa Boiss. on the growth of Pseudomonas aeruginosa. Materials and Methods: In this laboratory study, the plant was dried in dark place and aqueous, alcoholic extracts of Barije's root, powder were prepared using Soxhlet method. The efficacy of 0.1 dilution of different values of extracts of Ferula gummosa Boiss. on the strain of Pseudomonas aeruginosa (PTCC 1430) were evaluated by disk diffusion, Agar-well diffusion, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) methods. Results: Pseudomonas aeruginosa was completely resistant to the aqueous extract, and the MIC for the methanol and ethanol extracts was 1.25×10⁴ μg/ml and 6.25×10³ μg/ml, respectively. Conclusion: Methanolic and ethanolic extracts of Ferula gummosa Boiss. have antimicrobial activity against Pseudomonas aeruginosa in in-vitro model.

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Background and Objective: Gastroenteritis due to Salmonella is common in human and considered as a global dilemma of public health. This study was done to determine the Pattern of serotyping and antibiotic resistance of Salmonella in children with diarrhea in Iran. Methods: In this laboratory study, 306 stool samples were collected from children with diarrhea in public health centers in Robat-karim, Tehran province, Iran. The specimens were enriched in Selenite F medium and then cultured on Hekton agar. The identification of Salmonella was carried out by conventional method and antimicrobial susceptibility testing was performed according to CLSI procedures. Results: Out of 306 stool samples, 7.2 % were identified as Salmonella species, as follow: 7 Salmonella typhi, 6 Salmonella paratyphi B, 3 Salmonella paratyphi C, 2 Salmonella paratyphi A and 4 samples were not identifiable. There was a significant relation between presence of WBC in fecal and salmonellosis (P<0.05). In drug sensitivity trends, 92.3% of Salmonella species were sensitive to chloramphenicol, ceftizoxime, Nalidixic acid and Amikacin. Conclusion: This study showed that Salmonella was the cause of children diarrhea in 7.2% in this region.

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Background and Objective: The generated genetic diversity in the microbial pathogens and drug resistant led to a growing interest to use herbal medicine. This study was carried out to determine the in vitro anti-bacterial activity of chloroform, ethyl acetate and hydroalcoholic extracts of Scilla persica Hausskn. Methods: In this laboratory study, chloroform, ethyl acetate and hydroalcoholic extracts were obtained from bulb of Scilla persica. The anti-microbial activity, the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of the extracts were evaluated on Staphylococcus aureus, Bacillus cereus and Escherichia coli using the disk diffusion (growth inhibition zone) and macro-dilution methods. Dimethyl sulfoxide (DMSO) was used as a negative control while nalidixic acid and ampicillin were used as positive control. Results: The maximum inhibition zone for ethyl acetate extract was 26.3±0.1 milimetre, 23.7±0.3 milimetre and 19.5±0.4 milimetre for Staphylococcus, Escherichia coli and Bacillus, respectively. The maximum inhibition zone of chloroform extract was found to be 16.4±0.2 milimetre and 14.9±0.3 milimetre for Staphylococcus and Bacillus, respectively. Conclusion: Antimicrobial activity of the chloroform and ethyl acetate extracts of bulb of Scilla persica on Escherichia coli, Staphylococcus aureus and Bacillus cereus are more effective compared to nalidixic acid and it is similar to ampicillin in in-vitro condition.

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Background and Objective: Leptospirosis is an infectious and zoonosis disease, which is caused by leptospira and is transmitted from animal to human. The rapid diagnosis can control the disease, therefore this study was carried out to determine the prevalent serovars of leptospira using micro agglutination test (MAT) in human and cattles. Method: In this descriptive study, 175 cattles and 67 suspected human serum samples were tested in five provinces in Iran during 2011-12. Serum samples tested by micro agglutination test using 20 live leptospira serogroup. Results: Ninty nine out of 175 (56.5%) cattle serum samples and 31 out of 67 (46.2%) human samples were positive against leptospira antigen. The most prevalent leptospira serovar in cattles and human were Serjoe hardjo (61.9%) and Serjoe serjoe (23%), respectively. The most frequent titer in positive samples was equal to be 1/400. Fifty percent of human positive samples belong to farmers between 20-40 years old. The common contaminations belong to polluted water (61.1%) and infected blood (28.3%), respectively. Conclusion: Using micro agglutination test, the most prevalent leptospira serovar in cattles was Serjoe hardjo and in human was Serjoe serjoe.

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Background and Objective: Ruta graveolens is a plant used in traditional medicine with variety of therapeutic effects. This study was done to evaluate the antimicrobial effect of hydro and alcoholic extracts of Ruta graveolens on 8 species of pathogenic bacteria. Methods: In this descriptive study, standard strains of Enterococcus faecalis, Staphilococcus aureus, Staphilococcus epidermis, Strptococcus pneumonia, Escherichia Coli, Klebsiella pneumonia, Salmonella typhi and Enterobacter Cloace were obtained from Iranian institute of scientific and industerial research center. The effect of hydro and hydroalcholic extracts of Ruta graveolens on the growth of bacteria was determined by disc diffusion and serial macro dilution methods. Minimum inhibitory concentration (MIC) for each extract was determined and the findings were compared with 8 common antibiotics including Co-trimoxazole, Oxycycline, Vancomycin, Erythromycin, Furazolidon, Tetracycline, amoxicillin / clavulanic acid and Ampicillin/sulbactam. Results: Hydro and hydroalcoholic extracts of Ruta graveolens did not show any inhibitory effect on growth of the pathogenic bacteria even in the presence of high concentration (3mg/ml). Conclusion: The extracts of arial organs of Ruta graveolens had no inhibitory effect on growth of the common human pathogenic bacteria.

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Background and Objective: Helicobacter pylori is the main gastric pathogen in human. BabA2 and Hsp genotypes are essential for enormous clinical outcomes in gastreodeoneal and dyspepsia. This study was done to determine the assessment of babA2 and hsp genotype frequency in Helicobacter pylori specimens isolated from digestive disorders patients. Method: This descriptive-analytic study was carried out on 80 digestive disorders patients in 5th hospital, Gorgan, northern Iran. Stomach specimen biopsy was taken by a gastroenterologist. Urease test, histopathologic assessment and DNA extraction were performed. The frequency of babA2 and hsp geno-types was determined using poly merase chain reaction. Results: In 80 affected patients with H.pylori, 36, 18 and 26 patients were found to suffer from gastritis, stomach cancer and stomach ulcer, respectively. 51 specimens (63%) were positive babA2 genotype. 49 specimens (61%) were positive hsp genotype. No significant relationship was found between babA2 and hsp geno types with stomach diseases. Conclusion: In spite of positive babA2 and hsp genotype in isolated Helicobacter pylori speicments from digestive disorders patients, this finding was not correlated with type of digestive disorders.

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Background and Objective: Drug resistance to tuberculosis and especially multiple drug resistance tuberculosis (MDR-TB) variants are a serious problem in tuberculosis patients and make difficulties in controlling the disease. This study was coducted for detection of common mutations causing drug resistance of mycobacterium tuberculosis strains among tuberculosis patients using line probe assay method. Method: In this descriptive study, fifty four sputum samples of tuberculosis patients were randomly selected in health centers of Mazandaran, northern Iran during 2012. After culturing of sputum samples on Lowenstein–Jensen medium, genomic DNA was extracted from colonies using CTAB method. Molecular analysis of mutations causing resistance to five different antibiotics including Isiniazide, Rifampin, Sterptomycine, Amicasin / Canamycine, Kinolon were performed using long probe assay (LPA) method. Results: Out of 54 sputum samples, three (5.5%), three (5.5%), four (7.4%) were resistance to Kinolon, Amicasin / Canamycine and Sterptomycine, respectively. Mutation in KATG was seen in 2 samples resistant to Isiniazide. Mutation in rpoB 516 was seen in 3 samples resistant to Rifampin. Four samples (7.4%) were resistant to the two anti-tuberculosis antibiotics, while three samples were resistant to Sterptomycine and Kinolon and one sample was resistant to Rifampin and Canamycine. Conclusion: 7.4% of sputum samples were resistant to the two anti- tuberculosis antibiotics. Line probe assay is a rapid and suitable method for detecting tuberculosis drug resistance.

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Background and Objective: Methicillin-resistant Staphylococcus aureus is a common pathogen responsible for health-care-related infections. This study was done to determine the prevalence of Meticilin - resistant Staphylococcus isolated from hand and nasal of hospital health worker. Methods: This descriptive study was conducted on 148 health workers in teaching hospitals in Sari, northern Iran during 2011-12. Samples were collected from fingers and noses and were cultured on mannitol salt agar immediately. Suspected colonies were identified using Gram staining, catalase and coagulase tests. Susceptibility testing was performed by disk diffusion method. Methicillin resistant strains were determined using micro dilution broth method. Results: Staphylococcus aureus was observed in 24 (16.2%) of individuals. 9.5% of population was resistant to Methicillin. The high portions of Staphylococcus aureus carreier were in the operation room, angiography and internal pediatric ward health worker. Methicillin Staphylococcus aureus resistanat were more common in nasal samples of the operation room personal and angiography ward health worker. All strains were sensitive to Vancomycin and Chloramphenicol and resistant to Penicillin and Amoxicillin. Conclusion: In this study the prevalence of the Staphylococcus.aureus in teaching hospitals health worker was low while Staphylococcus aureus resistant to methicillin was higher than other reports in Iran.

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Background and Objective: MIRU-VNTR typing is currently one of the most frequently-used standardized genotyping systems in molecular epidemiology of tuberculosis in the world. This sudy was done to determine the Mycobacterium tuberculosis genotyping by MIRU-VNTR method. Methods: This descriptive study was done on sputum, gastric lavage clinical specimens of 53 tuberculosis suspected patients. Fifty-three isolates were identified by 16S rRNA and Rv-typing followed by RD typing. They were then subjected to a 12-locus (ETRA, ETRB, ETRC, ETRD, ETRE and ETRF, MIRU-10, MIRU-26, MIRU-39, MIRU-30 plus QUB-11b) MIRU-VNTR typing system. Results: In MIRU-VNTR typing, forty-four types were identified with 13 isolates classified in 4 clustered and the remaining 40 isolates representing 40 orphan patterns. In comparative analysis of MIRU-VNTR loci, MIRU-26 with 7 alleles displayed the highest diversity level (Simpson’s diversity index = 0.767. Out of the 53 isolates, only one was identified as Mycobacterium bovis. All the remaining isolates were characterized as Mycobacterium tuberculosis. None of the samples was affected to Mycobacterium complex strain. No evidence of either double or co-infection of the patients with more than one species/strain was detected. Conclusion: While the genomic diversity observed by MIRU-VNTR typing sounds extensive, the population genomic structure on the whole however, seems to be homogenous. Recent transmission between studied patients does not appear to be a frequent event as only 13 isolates representing 4 MIRU-VNTR types, were assumingly epidemic.

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Background and Objective: Bacterial resistance to Imipenem is increased in bacterial infections in Iran. In regard to the importance of Imipenem in the treatment of nosocomial infections and the key role of disc diffusion method as a major antibiotic susceptibility testing assay, this study was done to determine the prevalency of imipenem-resistant bacterial strains isolated from hospital and accuracy of Iranian imipenem disc product. Methods: In this descriptive-analytic study, 241 bacteria were isolated from patients in different wards of the Baqyatallah hospital in Tehran, Iran during 2013-14. After streaking of the organisms, identification was performed by all conventional biochemical tests. The bacterial resistance to imipenem was determined by disk diffusion method using Iranian and Mast imipenem discs. True imipenem-resistant isolates were examined for susceptibility to six different antibiotic including Ciprofloxacin, Gentamicin, Cephalexin, Azitromysin, Tetracycline and Ceftazidim, using disk diffusion method. Results: The most prevalent isolates organisms were gram-negative bacilli (Klebsiella, Escherichia coli, and Pseudomonas aeruginosa, respectively). The common clinical source was urine and wound samples, respectively. Resistant to Imipenem was 68 (25.7 %) and 19 (7.8 %) based on the results of Iranian and Mast Imipenem discs, respectively. False results for Iranian Imipenem discs was higher than Mast Imipenem discs (P<0.05). Among the 19 true Imipenem resistant isolates, 17 micro organisms were Pseudomonas aeruginosa. 57% of isolated resistant to Imipenem were isolated from ICU ward. The most resistance was seen to Gentamicin (84%) and the lowest was seen to Ciprofloxacin (63%). 84% of isolated samples were multi drug resistance. Conclusion: Although a small percentage of the isolates obtained as important nosocomial pathogens were resistant to Imipenem, but the rate of multiple resistance and high rate of isolates obtained from ICU was noticeable.

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Background and Objective: Yersinia enterocolitica is a worldwide pathogen belong to genus Yersinia. The association between acute childhood diarrhea and other diseases caused by Yersinia enterocolitica has been established by several researchers. Due to the lack of sufficient information on other pathogenic Yersinia species, this study was done to determine the prevalence and the pattern of antibiotic susceptibility of atypical Yersinia spp isolated from children, less than 14 years old. Methods: This descriptive cross - sectional study was carried on 384 children with diarrhea whom referred to the Tehran children medical center, Tehran, Iran during August 2011 to August 2012. 384 fecal specimens of children were transferd to the laboratory and cold enrichment in alkaline buffer with pH of 7.2 for 21 days. The samples were cultured in Cefsulodin-Irgasan-Novobiocin Agar (CIN) differential media in 7, 14, and 21 days. The identification of Yersinia species were carried out by conventional procedure. Antibiotic susceptibility test to Ciprofloxacin, Co-trimoxazole, Tetracycline, Chloramphenicol, Erythromycin, Ampicillin, Gentamicin, Penicillin were determined by standard disk diffusion method. Results: Out of 384 fecal samples, 3 (0.7%) were infected with Yersinia. Three species of Yersinia were Y.enterocolitica, Y.Kristensenii and Y.frederiksenii. All three strains were sensitive to Cotrimoxazole, Tetracycline, Chloramphenicol, Ciprofloxacin and Gentamicin. Conclusion: This study showed that atypical Yersinia play important role in diarrhea. Therefore, more attention should be noticed to atypical Yersinia species in addition to Yersinia enterocolitica.