Jundishapur Journal of Microbiology
Volume:5 Issue: 4, Oct 2012

Mutations have been described in all of the four open reading frames of the hepatitis B virus (HBV), however, from a clinical perspective the surface escape mutant is the most troublesome. Hepatitis B surface antigen (HBsAg) variants may impair diagnosis, or allow the virus to escape vaccine-induced immunity or passive immunoglobulin therapy. HBV mutants with amino acid substitutions, within the common “a” determinant of HBsAg have been identified, and as a result, the HBsAg cannot be detected in some assays (diagnostic-escape). In these situations, the HBsAg mutants may arise in patients with a HBV infection, but they have been diagnosed as HBsAg negative. This review deals with the latest results on the performance of HBsAg assays, as well as the reactivity of native and or recombinant mutants of HBsAg.

The Lactobacilli belong to lactic acid bacteria, whose primary fermentation end product from sugars is lactic acid and that is why foods are conserved. Lactic acid bacteria have been used for millennia in the production of silage. Therefore, they are an indispensable part of intestinal microflora in human and animals. This research meant to isolate lactic acid bacteria with significant effects from different environments. In this study, heterofermentative LAB were isolated from cheese, yoghurt and corn silage in Broujerd, Iran. The standard biochemical methods were applied. Acid tolerance was studied by exposure to acidic PBS and growth in bile salt was measured by the spectrophotometric method. The isolated bacteria were studied for antagonistic effects on environment isolated E.coli, bacteriocin and biosurfactant production. Bacterial DNA was extracted, and amplified by PCR method. The 3 isolates from cheese, yoghurt and silage were effective against isolated E.coli and could produce biosurfactants. Phylogenic relationships of the 3 potential candidates were determined comparing the 16Sr DNA gene sequences, they were found to be as 3 isolates of Lactobacillus buchneri, L.brevis and L.kefiri that were effective on the isolated E.coli from environment. It was found that the isolated bacteria produced biosurfactants that had a great potential for different industries

Recent evidences have revealed that in more than 65% of microbial infections, biofilms have critical roles. The ability of yeasts to form biofilms on surface of medical devices such as urine catheters is an important reason of the capability of these microorganisms to cause human disease. The aim of this study was to isolate and identify yeasts on the surfaces of urine catheters and to investigate their ability to form biofilms.Patients and In this research, 55 urine catheters from patients of ICU award of Army Family Hospital in Tehran (Iran) were assayed. The catheters were taken aseptically to the laboratory for studying biofilms. Then they were sonicated and cultured on Sabouraud dextrose agar, CHROM agar and Corn meal agar. Examination of germ tube, sugar absorption and PCR method by two primers of ITS1 and ITS4 were used to identify pathogenic yeasts. According to the classical methods and molecular techniques, Candida albicans, C. krusei, C. glabrata and C. tropicalis were identified. The results show that yeast biofilms can form on the surface of catheters. Candida species are the yeasts which were isolated from these surfaces of infectious patients. C. tropicalis was the most abundant species which was isolated from the patients of this study.

Toxoplasma gondii is a unicellular apicomplex organism, belonging to the Toxoplasma genus. The parasite infects humans, as well as mammalians and different species of birds, and it can be propagated in a wide range of host cells. There have been no appropriate molecular or serological studies carried out previously in Iran on the prevalence of Toxoplasma gondii in rodents. Therefore, the present study has been carried out to provide genetic identification and determination of wild rats in Tehran, Iran. Forty rats in Tehran were caught with traps. Subsequently, their brains were removed under sterile conditions, DNA extraction was performed with a phenol and chloroform method. In the current study, a repetitive sequence in the genome T. gondii was used for identification with a specific primer. By sequencing the purified Polymerase Chain Reaction product, seven strains were determined out of the positive samples. Of the forty samples, 20 samples (50%) were positive for the 529-bp band. Samples No. 21 and No. 28 had 95% and 92% similarity with the RH strain sequence, respectively, which had the highest identity rate. The identity rate for samples No. 16 and No. 28 was 82% and 81%, respectively, which had the lowest rate of identification. The contamination rate was determined to be 50% using the PCR method. It can be stated that rats play an important role in the preservation of the Toxoplasma life cycle in Tehran. According to the alignment of results obtained from the seven sequenced samples, the highest similarity was observed with the RH strain (81-95%).

Facultative marine fungi could potentially be arsenic tolerant and may be able to remove this highly poisonous metal from the environment. The objective of this work was to explore the degree of tolerance and removal efficiency of two facultative marine fungi. Facultative marine fungi Aspergillus flavus and Rhizopus spp. were exposed to 25 mg/L and 50 mg/L sodium arsenite (As (III)). Tolerance of these species to the test concentrations was assessed by studying their biomass accumulation. Accumulation of arsenic by the fungal biomass was also evaluated. Our study revealed that both A. flavus and Rhizopus sp. exhibited tolerance towards the test concentrations of arsenic. Both of the test fungi also exhibited arsenic accumulation. Rhizopus sp. was found to be a slightly better potential accumulator. This study reveals that the test fungi can be harnessed as bioremediation agents for arsenic contaminated sites

Sugar alcohol erythritol is a non-caloric sweetener, non-cariogenic, and safe for diabetics because of no change to blood glucose and insulin levels after oral administration. Erythritol cannot be degraded by any enzymatic systems and must be eliminated from the blood through the kidney. The aim of this study was production and optimization of erythritol from glucose by Yarrowia lipolytica. Y. lipolytica DSM70562 was cultivated at 30°C in a 250 mL Erlenmeyer containing 50 mL of production medium composed of 200 g/L glucose, 10 g/L yeast extract, 10 mg/L MnSO4.4H2O, and 2 mg/L CuSO4.5H2O. Erythritol was separated from the sugars and other polyols by thin layer chromatography. Total polyols was determined using colorimetric method of Bok and Demain, and erythritol was also eluted from the paper and determined by this colorimetric method. In a batch culture with 200 g/L glucose at pH 5.5, an erythritol producer of Y. lipolytica capable to produce 27.8 g/L erythritol after seven days was selected, correspondingto a 21.52% yield and a productivity of 0.165 g/L/h. In this investigation we optimized the production medium and through altering medium components that resulted in a drastic change in polyol composition. Present study reports the production of erythritol for the first time by a Y. lipolytica strain DSM70562. Due to increasing demand for erythritol as a low caloric sweetener in food industry, its production via biological processes is becoming increasingly important.

In recent decades bacteriophages have been used as treating agents against some pathogens. Also, bacteriophages could be considered as alternatives of antimicrobial agents in plant protection. This study aimed to isolate a pathogen from potato (Solanum tubersom) tubers (Pseudomonas putida), and of its specific bacteriophage from soil and wastewater. Infected samples of soft rot potato tubers were collected from Flavarjan farms (Isfahan province, Iran) to isolate and identify P. putida by biochemical and molecular methods. Soil and wastewater samples were obtained locally to isolate the bacteriophage attributed to P. putida. Soil suspension was centrifuged and then filtrated by 0.2 micrometer Millipore filter. The wastewater was directly filtrated by 0.2 micrometer filter after centrifugation. After incubation of isolated bacteria together with phage contained solution, plaques were detected in nutrient agar. Subsequently, clearance of P. putida liquid culture incubated by added filtrated bacteriophage was observed. The structure and morphological characteristics of P. putida related bacteriophage was remarked by transmission electron microscopy (TEM). Isolated strain sda2 was identified as Pseudomonas putida with related accession number HQ423667. The result showed that isolated bacteriophage belonged to Cystoviridae family. We isolated a new strain of P. putida as well as a novel bacteriophage through which potato disease caused by the bacterium could be treated.

Blastocystis is a common protozoan parasite in mammals, birds, amphibians, reptiles, fish, arthropods, and annelids. This parasite has some subtypes, which pathogenicity status of them still remained controversial. Some of Blastocystis subtypes are potentially pathogenic to human. This study has identified the Blastocystis hominis subtypes and their prevalence rates in Hamadan. During two months of summer 2011, a total number of 250 human fecal samples referred for parasitology examination to Beasat Hospital and a few clinical laboratories of Hamadan city were collected. The samples were examined by direct method and formalin-ether. 41 samples exhibited positive results for B. hominis thereby were cultured in Locke-egg medium. After the growth and in order to genotype identification, B. hominis isolates were amplified by PCR, using seven pairs of sequencestagged site primers. In this study, three subtypes of B. hominis consisted of one [SB83], two [SB340] and three [SB227] were identified. The most dominant genotype was SB83 with 56.1 % frequency. The prevalence rate of genotype SB227 and SB340 were 22 % and 7.3 %, respectively. Coexistence of genotypes SB83 and SB227 was detected in 14.6 % of positive cases. This is the first study in Hamadan on genotyping of B. hominis, which may trigger other epidemiologic and zoonotic studies on different subtypes and hence control clinical manifestations of infection.

Staphylococcus aureus is a major nosocomial pathogen world wide. Mupirocin plays a crucial role in strategies designed to control outbreaks of S. aureus. The aim of this study was to determine the frequency of mupirocin resistance in S. aureus strains isolated from nasal carriers among the hospitalized patients at Kermanshah Hospital, Iran.Patients and A total of 174 S. aureus isolates (sensitive and resistant to methicillin) were collected from the nasal anterior nares of hospitalized patients. All isolates were tested for mupirocin susceptibility by a disc diffusion method. The minimum inhibitory concentration (MIC) was determined by an E-test and they were also analyzed by a PCR for the presence of ileS-1 and ileS-2 genes. Utilizing the disc diffusion agar method, E-test and PCR, all of the S. aureus strains tested were susceptible to mupirocin. In this study, the range of mupirocin MICs was determined to be between 0.064 and 4 μg/ml. There was a significant association between MIC observed and multi-drug resistant (MDR) carriage (P value 0.04), and resistance to oxacillin (P value 0.004). This is a report of an initial survey of mupirocin resistance in S. aureus, in Kermanshah where the use of mupirocin is still limited. Perhaps the sensitivity of all isolates to mupirocin in this study is due to the less common usage of this antibiotic, especially in the form of nasal and site sample collections.

hepatitis B virus (HBV) infection is a major public health problem that affects billions of people worldwide. The lack of information on HBV prevalence among the general population is an obstacle to formulate effective policies to reduce the burden of viral hepatitis. This population based serological survey was conducted in Kermanshah province to determine the local prevalence and risk factors of HBV infection.Patients and 1979 healthy subjects were selected from all districts of Kermanshah province (in the west of Iran) using random cluster sampling. Subjects between 6 and 65 years of age were included with mean age of 35 ± 13. Serum samples were tested for HBcAb, HBsAg and anti-HDV antibody. To carry out lab tests the third generation of ELISA was used. Various risk factors were recorded and multivariate analysis was performed. The prevalence of HBsAg and HBcAb in Kermanshah was 0.75% (95% CI 0.44; 1.21) and 8.28% (95% CI 7.13; 9.56), respectively. One case of HDV-Ab was found. Predictors of HBsAg or HBcAb in multivariate analysis were: old age, being male, history of tattooing and history of dental procedure. approximately 8% and less than 1% of general population in Kermanshah are HBcAb seropositive and active carriers of HBV infection, respectively. Age, sex and history of tattoo and dental procedures are major risk factors of HBV seropositivity in this province.

Toxoplasma gondii is an obligate, intracellular parasite, which is widely spread in the world. The parasite is able to infect all warm-blooded hosts including human. The infection occures via consumption of food or water containing oocytes, eating undercooked meats containing tissue cysts, and placenta. Undercooked meat consumption is one of the most important ways of Toxoplasma transmission especially in pregnancy period. Raw and undercooked meats have been reported responsible for 50 % of congenital toxoplasmosis. The current study was conducted to determine the prevalence of T. gondii in lamb and beef, and also meat products by molecular method in Ahvaz,southwest of Iran. Totally 190 samples were collected from local retailers in Ahvaz city. Samples of tongue, heart and muscle were taken from 50 lamb and 50 beef distributors and 90 meat product samples (sausages, hamburgers and salami, 30 samples of each). Collected samples were minced by electric meat grinder. DNA was extracted from 190 meat and meat product samples by Qiagen DNA Mini Kit. specific primers for the T. gondii B1 gene was used to detect the parasite in samples, by PCR method. A total of seven lamb out of 50 (14 %) and two beef out of 50 (4 %) were found as positive for T. gondii cyst. The parasite was not isolated from any of the meat product samples. The detection of the parasite in slaughtered animals, indicated that the risk still exists for food-transmitted toxoplasmosis, and consumption of raw or undercooked meat can transmit the infection to human community.

Candida vaginitis is a common fungal infection among adult women and it has been estimated that 75% of all adult women experience at least one period of vulvovaginal candidiasis in their lifetime. Several predisposing factors, such as diabetes mellitus, using contraceptive, pregnancy, and broad-spectrum antibiotics are reported as main risk factors for the infection. While, the main etiologic agent of vulvovaginal candidiasis is Candida albicans, more antifungal resistance has been reported among non-albicans species. The aim of the present study was to determine susceptibility patterns of vaginal isolates of Candida to eight antifungal drugs including, clotrimazole, miconazole, terbinafine, nystatin, itraconazole, fluconazole, ketoconazole, and econazole.Patients and Tested organisms were C. albicans 53 (79.1%), C. glabrata 8 11.9%), C. tropicalis 4 (5.9%) and C. krusei 2 (2.9%) that were isolated from vaginal infected patients. Disk diffusion method was used to evaluate susceptibility patterns. Paper disks containing clotrimazole, miconazole, itraconazole, fluconazole, ketoconazole, econazole, nystatin and terbinafine were applied for susceptibility tests. In the present study 2 isolates of C. krusei were sensitive to ketoconazole, clotrimazole and miconazole. In addition both isolates were resistant to fluconazole, nystatin, econazole and terfinafine. Only one isolate of C. tropicalis was sensitive to miconazole and terbinafine and two isolates to clotrimazole. Highest sensitivity of C. albicans to antifungal drugs was seen against miconazole (49 of 53 isolates) followed by, clotrimazole (41), terbinafine (28) and ketoconazole (13) whereas 43 isolates were resistant to fluconazole and econazole antifungals. All 8 isolates of C. glabrata were resistant to fluconazole, whereas all isolates were sensitive to miconazole. Antifungal sensitivity testing suggests that vaginal isolates of Candida were most sensitive to miconazole, clotrimazole, and terbinafine, and least sensitive to econazole and fluconazole.

Mumps, measles and rubella viruses lead to various kinds of complications such as meningoencephalitis, deafness, congenital abnormalities and even cause mortality in malnourished patients,. Since 2004, MMR vaccination in two series of one year of age and four to six years has been administered to Iranian children as a part of routine vaccination program. Recently, MMR vaccination schedule has been changed to one year and 18 months series. Since MMR vaccine has been recently entered childhood vaccination program, this study was performed to determine immunity response against mumps, measles and rubella six months after one year and four to six years of age vaccination. Patients and In a cross-sectional study, antibody titers after MMR vaccination at 18 months (six months after dose of one year) in 70 children, and at 6.5 years (six month after dose of six years) in 90 children referred to Ahvaz Abuzar Children’s Hospital Vaccination Clinic during 2007-2008 were detected by ELISA method. In 70 children (34 boys and 36 girls) who were vaccinated at one year, 30 (42.9 %) had antibody against measles, 63 (90 %) against rubella and 41 (58.6 %) against mumps. In 90 children (54 boys and 36 girls at 6.5 years of age (six months after vaccination), 41 (45.6%) children had antibody against measles, 79 (87.8 %) against rubella and 69 (76.7%) against mumps. the results of this study showed that after MMR vaccination, the level of antibody for measles was about 45 % and for mumps about 50-80 %. This level of immunity is not acceptable for successful vaccination. while the level of antibody against rubella was sufficient. For better evaluation of MMR vaccination, further studies and from other parts of the country is needed.

Leptospirosis is a systemic infectious disease caused by pathogenic bacteria belonging to the species of Leptospira, it is considered to be the most common zoonosis in the world. This is a serious and sometimes fatal infection which is transmitted from animals to humans by entering the digestive tract or mucosal membrane. Within the initial 10-12 day period, the patient may experience no or relatively minor symptoms, then the bacteria enters the blood system and causes contamination of the internal organs, especially the liver. This study prospectively evaluated two serological methods, the microscopic agglutination test (MAT) and indirect immunofluorescence assay (IFA) with the aim of identifying leptospiral agents quickly, in order to prevent and control leptospirosis diseases.Patients and In this study, 90 blood samples and their serums, were collected from patients showing clinical symptoms of leptospirosis, and these were analyzed with MAT and IFA tests, to test for the presence of leptospiral agglutinins. In this study we used five serogroups of Leptospira interrogans, which have been identified as the dominant serogroups in Iran (Pomona, Canicola, Grippotyphosa, Icterohaemorrhagiae and Sejro hardjo). The results obtained showed that when compared to the IFA, the MAT was a more sensitive test. The IFA method also identified certain specific properties of the serogroups; Pomona, Canicola and Icterohaemorragiae, which are detailed in the article. Serological testing is the most widely used method for diagnosing leptospirosis, and the MAT is considered to be the gold standard test for the diagnosis and detection of leptospiral antibodies in both human and animal sera, for the infecting serovar and serogroup

Entamoeba histolytica/Entamoeba dispar and Enterobius vermicularis are the major health problems in the developing countries especially in Iran. The prevalence of infection is variable among different social groups in the world. Since elderly and mentally retarded are high risk group, the present survey was carried out in order to determine the prevalence of intestinal parasites especially these parasites in elderly and mentally retarded residence in Golabchi Center, Kashan, Iran. In this Cross-sectional study a total of 243 stool samples and 279 Scotch tapes from elderly and mentally retarded people were collected. Intestinal parasitic infections especially E.histolytica/E.dispar was determined by Stool examination. Scotch tape was used for diagnosis of Enterobius vermicularis. The demographic data were recorded by questionnaire and were analyzed by SPSS and X2. The overall infection rate of intestinal parasite was 78.7% (191 out of 243 subjects). The prevalence of E.histolytica/E.dispar and E.vermicularis in elderly were 16.8%, 25.5% and in mentally retarded 15%, 49.1% respectively. Prevalence of pathogenic parasites was: Taenia spp. 1.6%, Hymenolepis nana 0.8%, one case of Strongyloides stercoralis, Blastocystis hominis 33.3%, Giardia lamblia 4.5%, Dientamoeba fragilis 1.6%. The rate of infection in mentally retarded was higher than elderly (P < 0.001). The prevalence of E.vermicularis in the male was 2.5 times more than female (P < 0.001). There was significant relation between annual itching and nail chewing and Enterobiasis (P < 0.05). This study showed that infection with intestinal parasites especially E.histolytica/E.dispar and E.vermicularis was higher than expected in elderly and mentally retarded. Due to importance of these parasites and some risk factors such as population density and an immunosuppressive background in elderly, health education and mass medication for control of disease is emphasized.

One of the most important factors in inducing the logarithmic growth of Streptococcus mutans, is a diet containing fermentable carbohydrates such as sucrose. The aim of the current research was to compare the ability of ordinary and probiotic chocolate to induce or inhibit the growth of S. mutans. Lactobacillus rhamnosus, L. plantarum and L. acidophilus as probiotic strains, were cultivated on MRS agar for 24 hours at 35° C in 5% CO2. S. mutans which is a dominant factor in causing dental plaque, was isolated from 20 samples of dental plaque and caries lesions in adults on Streptococcus selective agar medium, and diagnosed by routine biochemical tests. The antimicrobial effect of three probiotic strains on S. mutans was evaluated by the deferred cross-streak method and susceptibility through the disk diffusion test. The antimicrobial effect of the probiotic supernatant powder was determined by a dilution method. Probiotic strains were added to dark chocolate with a concentration of 108 CFU/mL and their antimicrobial effect on S. mutans was evaluated by the disk diffusion susceptibility method. Survival of the probiotic strains in chocolate and pH shifts were studied in different environmental storage conditions. The results showed that S. mutans was the dominant strain in all of the 20 dental plaque samples. L. plantarum showed the most antimicrobial effect on S. mutans with the maximum diameter of growth inhibitory zone, 35 mm and 78 × 78 mm in the disk diffusion method and deferred cross-streak method, respectively. Probiotic supernatant powder inhibited S. mutans strains in concentrations of 500-700 and 100-300 mg/ml at t = 0 and t = 24, respectively. Comparing the results in terms of maintenance and storage of probiotic chocolate, it showed that the best condition to keep this chocolate is at 4˚ C (refrigerated) with a probiotic survival of 25 to 30 days. The pH level during this period decreased from a pH of 5 to 4. Probiotic chocolate containing L. rhamnosus was shown to have the greatest antimicrobial effect on S. mutans with a maximum diameter of growth inhibitory zone of 75 mm during 59 days storage at an ambient temperature and 4° C. These results suggest that probiotic chocolate is able to inhibit the growth of S. mutans rather than ordinary chocolate

Hydatid disease is caused by Echinococcus spp. especially Echinococcus granulosus that is the most common cause of hydatid disease in humans. This disease occurs either through direct contact with infected dogs or indirectly from the ingestion of contaminated water or food with eggs of worms. The most common site in human is the liver (59-75%), followed in frequency by lung (27%), kidney (3%) and bone (1-4%). The authors report a case of the pelvic bone hydatidosis in a 27-years old patient, appearing with pain and a mass in the pelvic region.