Jundishapur Journal of Microbiology
Year:2010 | Volume:3 | Issue:4 (S.N. 9)|Papers Count:8

Introduction and objective: Escherichia coli is a major cause of urinary tract and other opportunistic infections. Emergence of antibacterial resistance and production of extended spectrum β-lactamases (ESBLs) are responsible for the frequently observed empirical therapy failures. ESBLs producing bacteria and AmpC are serious threat in treating bacterial infections. Existence of various mechanisms which create resistance to antibiotics accounts for treatment failure in infections with these bacteria. The aim of this study was to determine the presence and the prevalence of bla CTX-M, blaSHV, blaTEM and blaAmpC b-lactamases genes in clinical isolates of E. coli in Kerman.Materials and methods: Agar dilution method was used to determine the minimum inhibitory concentration of cefotaxime, ceftazidime and ceftizoxime in138 E. coli isolates. Resistance to imipenem, cefepime and cefoxitin was determined by disk diffusion method. Phenotypes of ESBLs and AmpC were also determined by combined disk method and non b-lactam inhibitor based method (boronic acid) respectively. PCR was used to determine blaCTX-M, blaSHV, blaTEM and blaAmpC genes in the ESBLs positive isolates.Results: From 138 E. coli isolates 68.1% produced ESBLs by phenotypic method. Incidence rate of blaTEM, blaSHV and blaCTX-M among ESBL producing isolates were 63.8%, 51% and 23.4%, respectively. Presence of blaTEM, blaSHV and blaCTX-M genes at the sametime was detected in10.6% of isolates. Simultaneous production of AmpC and ESBLs was observed in 6.5 % of isolates. blaAmpC gene by PCR was seen in three isolates.Conclusion: TEM and SHV b-lactamases are the dominant b-lactamases in this area. Simultaneous production of various b-lactamases in these isolates reflects the increased ability of these isolates against antibacterial agents and; therefore, this can cause serious problems in future in the treatment of infections especially nosocomial infections of such isolates.

Introduction and objective: Coagulase negative Staphylococci (CoNS) are often isolated from blood cultures which may represent either contamination or bacteremia. Repetitive sequence-based PCR (rep-PCR) as a suitable and potential tool permit differentiation of isolates to species, subspecies and strain level. The aim of this study was analysis of DNA fingerprint patterns and detection of similarity or differentiation of CoNS strains isolated from pediatric patients blood cultures.Materials and methods: In this study, coagulase-negative Staphylococci isolated from hospitalized pediatric patients, were examined. DNA was extracted by using a DNA extraction kit and then diverse-sized DNA fragments consisting of sequences between the repetitive elements were amplified by rep-PCR. Amplified PCR products in different sizes were separated in agarose gels.Results: Forty-seven strains of CoNS were differentiated by DNA fingerprints generated by rep-PCR. Rep-PCR generated 2-12 different-sized PCR products visible on ethidium bromide stained agarose gels and 29 different fingerprint patterns. A unique fragment was identified in multiple blood cultures from each of seven different patients. Three patients each had two isolates that were closely related, one patient had two isolates that were possibly different, and three patients each had two isolates that were different.Conclusion: Rep-PCR is a rapid and suitable technique for epidemiological studies and this method with high discrimination could detect similarity or differentiation of strains isolated from bacteremic patients consequently.

Introduction and objective: Detection of the common allergen airborne fungi in any region is critical for prevention and treatment of allergic fungal diseases. Therefore, this study was conducted to identify the most common airborne fungal species of Isfahan, investigate their allergic reactions in animal and obtain local fungal strains for use as antigens in allergy tests to be used.Materials and methods: An open plate method was used to scan airborne fungal contents over 12 months in Isfahan. On the same days every week, triplicate samples were collected at three different locations in the morning, at noon and in the evening. The fungal culture media were incubated at 25oC until growth appeared and then the airborne fungi were identified by routine mycological laboratory methods. The extracts of the most common airborne fungi isolated, were examined with skin prick test for allergic reactions in laboratory animals.Results: During this study, the most abundant airborne fungi identified in Isfahan were species of yeasts, yeast like (Candida spp., Geotrichum spp., and Trichosporon spp.), and mold (Cladosporium spp., Penicillium spp., Aspergillus spp., and Alternaria). Positive skin reactions were observed with Cladosporium spp.(40%), and Aspergillus spp. (21%), Alternaria spp. (17%), Penicillum spp. (15%) and Geotrichum spp. (7%).Conclusion: It is concluded that fungi have a significant role in infecting immunocompromised hosts, information obtained in the present study contribute toward a better understanding of the pattern of occurrence of airborne fungi, and may assist allergists, clinicians and epidemiologists to treat the diseases.

Introduction and objective: Patients with candidiasis could be treated with antifungal drugs. Due to side effects and drug resistance, many studies have been conducted to investigate essential oils’ antifungal effects. The aim of the present study was to determine anticandidal activity of some essential oils.Materials and methods: In this study, the effect of thyme, pennyroyal and lemon essential oils on Candida isolated from vulvovaginal infection were investigated experimentally by using micro dilution method. Serial dilution of thyme (0.002-4%), pennyroyal (0.004-8%) and lemon (0.15-32%) essential oils accompanying to controls and also amphotericin B (0.008-16μg/ml) and fluconazole (1-2048μg/ml) were used.Results: Thyme’s essential oils had the most anti-candidal activity followed by pennyroyal. Candida albicans was the most sensitive species (0.008-0.062%). Thyme and lemon essential oils had the most (0.008-0.271%) and least (1-32%) anticandidal activities, respectively. The candidal growth was inhibited by amphotericin B at 1μg/ml; whereas the anticandidal activity of fluconazole was 29.647-978.824μg/ml. the effect of thyme essentia l oil was similar to amphotericin B.Conclusion: Because of the strong anti-candidal effects of thyme which was proved through in vitro tests in our study, it is proposed to do further research in the treatment of candidiasis with thyme experimentally.

Introduction and objective: Candida albicans is the most virulent among the Candida species, and can cause several forms of candidiasis in human. Extracellular phospholipases in C. albicans is discussed as one of the virulence factors. The present study, focused on extracellular phospholipase activities in different isolates of C. albicans isolated from vagina and urine samples from Ahvaz, Iran. In addition, phospholipase activities were compared in C. albicans isolated from two different sources.Materials and methods: In the present study, phospholipase activity of 100 isolates of C. albicans with urine and vaginitis origin was demonstrated using Sabouraud's dextrose agar supplemented with egg yolk.Results: The phospholipase activity was detected in all tested isolates with a high level in Pz<0.70. In the present study phospholipase activity with higher Pz values was more common in vaginal isolates (84.7% isolates with Pz value <0.70) compared with 75% in urine isolates.Conclusion: In the present study, 100% clinical isolates of C. albicans from vaginitis and urine samples demonstrated phospholipase activity.

Introduction and objective: Hydatidosis is one of the most important and commonly found parasitic zoonoses in both humans and different animals, which is caused by the cestode helminthes Echinococcus granulosus. The diagnosis of the disease is primarily based on imagery techniques. Thus, highly sensitive and reliable serologic methods are required to confirm the diagnosis. AntigenB (AgB) and protoscoleces antigen (PSC Ag) were purified as two specific parasitic antigens and then evaluated against sera from two groups of hydatidosis and non-hydatidosis (control) subjects using the western blotting method in order to identify the most sensitive and specific antigen.Materials and methods: Sera samples were taken from 22 patients under operation for hydatid cyst. 16 patients were also included as control group. Cyst fluid and protoscoleces were extracted and partially purified in a protein A column. Using SDS-PAGE, subunits of the cyst fluid antigen, AgB, and PSC Ag were identified. Finally, the subunits were transferred from gel to nitrocellulose membrane in a western blot test and reacted with hydatid and control sera in order to assess their sensitivity and specifity.Results: Three antigens were identified as the subunits of AgB while 10 antigens were identified as PSC Ag. The sensitivity and specifity of AgB subunits in the western blot test were 77% and 100%, respectively. None of the PSC Ag subunits had both high sensitivity and high specifity concurrently.Conclusion: It has been shown by the western blot test that the AgB 8/12 and 16 KDa subunit components had high diagnostic sensitivity and specifity levels (81% and 100%, respectively) and that they could presumably assist the physician in his pre- and postoperation diagnosis of hydatid cysts.

Introduction and objective: Giardia duodenalis is a ubiquitous protozoan parasite in several animal species and humans. The objective of the present survey was to investigate the prevalence of G. duodenalis in the fecal samples of companion dogs in Ahvaz area, south-western Iran.Materials and methods: A total of 150 companion dogs of different ages were examined for antigenic detection of G. duodenalis in fecal samples by a commercial Giardia Antigen Test Kit. Fecal centrifugation-flotation technique was also used for identification of cyst by microscopic examination. The studied dogs were selected from those referring to Veterinary Hospital of Chamran University Ahvaz from June 2007 to January 2010. They were divided into two groups clinically (diarrheic and non-diarrheic) and based on age into three groups (<6 months, 6 months-3 years and >3 years).Results: Six out of 150 fecal samples (4%) were positive for antigen of G. duodenalis by immunochromatography assay. Prevalence was significantly higher in young dogs less than 6 months (11.6%) compared with adult dogs 6 months-3 years (1.6%) (P=0.041). The infection was more common in diarrheic dogs (18.5%) compared with non-diarrheic dogs (0.8%) and the difference was significant (P=0.001). Microscopic examination on fecal samples showed that 2.7% (4 out of 150) of the studied dogs were positive.Conclusion: The infection rate of giardiasis in companion dogs' particularly in diarrheic dogs is considered to be critical from the viewpoint of public health. Our results indicate that this parasite is a zoonotic infection in Ahvaz district.

Introduction and objective: Cutaneous leishmaniasis (CL) is considered as an important health problem in many parts of Iran especially in Mashhad, north-eastern part of Iran. Various species of Leishmania cause the disease. Identification of Leishmania parasites is useful for control and preventive plans. Although epidemiological and clinical findings are necessary but they are not sufficient for identification of causative agents of CL. In order to identify Leishmania spp. a definite molecular technique, Polymerase Chain Reaction (PCR) method was used over a 12 months period.Materials and methods: A total of twenty-one patients participated. Direct smear and culture in modified NNN medium followed by sub-culture in RPMI-1640 were performed for each case. Genomic DNA was extracted by using proteinase k and amplified by specific primers of kDNA. The PCR product was analysed by gel electrophoresis using 2% agarose. Gel staining was performed by ethidium bromide. The presence of 620bp fragment indicated Leishmania major and 800bp indicated L. tropica.Results: Of 21 positive cultures out of 53 positive samples, nineteen isolates were identified as L. tropica and two others were identified as L. major. However, by previous investigations, Mashhad was known, as an endemic focus for Anthroponotic Cutaneous Leishmaniasis (ACL), but it is now concluded that both ACL and Zoonotic Cutaneous Leishmaniasis (ZCL) are present in Mashhad and L. tropica is the dominant species.Conclusion: Both L. tropica and L. major are the causative agents of cutaneous leishmaniasis in Mashhad. L. tropica is the dominant Leishmania species in Mashhad. However PCR technique is a very reliable method to detect Leishmania DNA, but it is not easy to obtain Leishmania culture samples.