Jundishapur Journal of Microbiology
Volume:5 Issue: 3, Jul 2012

Staphylococcus aureus is a human bacterial pathogen, known to cause a variety of illnesses and infections in the hospital and community settings. It produces a large number of virulence factors used for host invasion, tissue colonization and destruction, leading to severe infections in both healthy and immunodeficient people around the world. In this paper, we studied the potential mechanisms related to methicillin resistant S. aureus (MRSA) infection, analyzed the significance of oxidative stress for survival of S. aureus, and re-identified the molecular structure, regulatory boxes, and regulons of PerR (peroxide responsive repressor) gene, a key modulator responsible for MRSA. Then, we further investigated how PerR functions in response to oxidative stress and how the PerR regulon affects S. aureus virulence. As a conclusion, we postulate that the regulation of PerR and its regulon indirectly influences the expression of virulence factors by prolonging the pathogen’s survival under harsh conditions that may lead to the increased risk of S. aureus transmission, infection, and spread of the disease

Swimming pools can transmit contagious diseases such as; fungal disease, otitis, conjunctivitis and amoebic meningoencephalitis. The aim of this study was to determine the level of microbial contamination and the physicochemical condition of the swimming pools. In this cross – sectional study, 200 water samples were collected from four swimming pools in Kashan, Iran. Temperature, pH and residual chlorine and turbidity of the pools were examined. Samples were concentrated through a membrane filter and sedimentation, to test for the presence of parasites, fungi, and bacteria. The results of the study showed that the mean of the physicochemical parameters, except in temperature, was standard in more than 60 % of the pools. Average temperature was higher than standard. The highest chlorine level was recorded in summer. Coliform bacteria was found to be positive in 3 % of the samples. Prevalence of saprophytic and opportunistic fungi was 27 %. Twelve species of fungi were isolated; the most common were Aspergillus, Penicillium sp, Rhizopus sp, and Fusarium sp, and the highest fungi pollution was observed in the summer. Prevalence of bacterial contamination was 9 %; bacteria isolate included Staphylococcus epidermidis, Bacillus subtilis and Escherichia coli. There was a significant association found between fungal and bacterial contamination with residual chlorine (P = 0.014, 0.001). The results showed that there were no parasites, or pseudomonas in Kashan’s swimming pools, however, the prevalence of opportunistic saprophytic fungal contamination was relatively high. Such conditions may be attributed to a high temperature and insufficient water treatment. In addition, there is a need to monitor water quality and improve staff training to increase users’ knowledge and awareness of the risks

Human Enteroviruses are members of the Picornaviridae family, they are nonenveloped,with icosahedral symmetry, positive RNA viruses and causes aseptic meningitis in both infants and adults. The aim of this study was to determine the relative frequency of Enteroviral meningitis among children referred to Ahvaz Aboozar hospital.Patients and 57 Cerebrospinal fluid samples were collected from patients with aseptic meningitis and White Blood Cell (WBC) count of more than 5x106/mm3, Enterovirus RNA was extracted with Roch extraction kit and Enteroviral infection was detected by Revers Transcriptase polymerase chain reaction (RT-PCR) test. Enteroviral infection was detected in 34 cases out of 57 patient (59.6 %), 19 patients were younger than 1 year old (55.8 %), 8 cases were between 1 and 2 years (23.5 %) and 7 cases were older than 2 years (20.5 %). The relationship between gender and prevalence was not significant. Most cases were found in winter. It was shown that human Enterovirus is the major cause of aseptic meningitis in Ahvaz, south west of Iran. The prevalence of Enterovirus infection was considerably high in this region. To decrease prevalence of Enteroviral infection, improved knowledge and personal hygiene is advised.

Nosocomial infections acquired during hospitalization depend on the characteristics of the microorganisms, with a high risk of these being acquired when the environment is contaminated. Cross-transmission of microorganisms by contaminated surfaces and the hands of health care workers are considered to be the main route of the spread of nosocomial infections and in many Mexican hospitals, information about microbial and fungi contaminants on indoor surfaces is insufficient. In this study, we explore the bacterial and fungal genera present on surfacestaken from; armrest beds, wash sinks, medical tables, and the hands of medical staff fromemergency, intensive care unit, inhalation therapy, stomatology and pediatric areas. The present study was conducted in a hospital located in Xalapa City in Mexico; the samples were taken during a 6 month period from August to December, 2010. Surface swab specimens were collected from predefined surfaces with cotton tipped applicators, pre-moistened with sterile saline and inoculated on Sabouraud dextrose or selective Eosin-Methylene Blue agar plates and incubated for 1 to 7 days at 28°C or 37°C in three triplications in order to isolate bacterial and fungal contaminants. We isolated and identified gram-negative bacteria and fungi and the results showed that the predominant bacteria were; Klebsiella spp. Pseudomonas spp. and E coli spp. The predominant genera of fungi were; Cladosporium spp. Microsporum canis., Aspergillusspp. and Penicillium spp. This study showed that all areas of the hospital have pathogenic fungi and bacteria, indicating that these are a potential source of cross-infection from the hands of health care workers to their patients.

In recent years, a number of antibiotics have lost their effectiveness due to the development of resistant strains, mostly through the expression of resistance genes. The aim of the present study was to investigate the antimicrobial property of Quercus brantii fruits and compare its effects with some current antibiotics. The antimicrobial activities of an ethanol extract of Q. brantii (Oak) fruits (brown cortex: B.C and white core: W.C) were tested in vitro against eight reference strains of enteric pathogenic bacteria. The antimicrobial activities of the extracts were examined based on the disc diffusion method. The results were evaluated as inhibition zones around the discs impregnated with B.C and W.C extracts at different concentrations (2 to 10 %). The antibacterial effect of the B.C ethanolic extract on Escherichia coli was significant and had a concentration-related effect, although there was no significant effect found on Helicobacter pylori. The W.C ethanolic extract has a high antimicrobial effect on Streptococcus pyogenes; at the same time significant antibacterial activity occurred against H pylori. Comparisons between the antimicrobial activities of these extracts (B.C and W.C) and standard antibiotics; gentamicin, colistin, and methicillin, showed that in the most commonly tested bacteria the antibacterial activity of these extracts was even greater than with the antibiotics. Analysis of the extracts components by gas chromatography, showed that tannins and phenolic compounds could be responsible for these antimicrobial activities. The results of this study showed that different parts of Q. brantii have antimicrobial activity against gastrointestinal bacterial pathogens. These antimicrobial activities, in almost all cases, were greater than with standard antibiotics

Candida albicans is one of the mouth normal flora which may cause failures in endodontics. The resistance of C. albicans to intracanal medicaments such as calcium hydroxide could reduce success rate root canal treatments. Due to recivening some reports regarding resistance of C. albicans to calcium hydroxide from different parts of the world, the aim of this study was to evaluate anti candidal effects of Iranian and Korean made injectable calcium hydroxide and to compare the results. In the present research, the antifungal effects of calcium hydroxide on seven clinical isolates and one standard strain of C. albicans were evaluated. For this evaluation, two methods were used including: inhibition zone and colony count. In all experiments distilled water and clotrimazole were used as negative and positive controls, respectively. In order to evaluate the effects of exposure time of calcium hydroxide on C. albicans growth, 30”, 5’, 1 and 24 hours of incubation periods were applied. In addition, to evaluate role the effect of calcium hydroxide concentration samples with saturated, 1/10, 1/100 and 1/1000 dilutions and also a saturated one were used. According to inhibition zone method, the mean diameters of C. albicans for Iranian and Korean made calcium hydroxide and clotrimazole were 17, 13 and 22 mm, respectively. Iranian and Korean calcium hydroxide did not show any anti candidal effects. By colony counting method, it was found that in longer exposure time, Iranian and Korean calcium hydroxide have more anti candidal effects, but no significant difference was observed between the two. Saturated and all other dilutions of calcium hydroxide base material indicated a significant statistical difference in anti candidal effect after 24 hours exposure in comparison with other periods. The Current study, confirmed that the inhibitory effect of Iranian and Korean calcium hydroxide on C. albicans, up to 24 hours is within low range. Higher concentrations of base calcium hydroxide, showed greater inhibition zone on C. albicans

A high seroprevalence rate of human immunodeficiency virus (HIV) infection has been reported among Iranian illicit substance users (ISUs). The aim of this study was to evaluate the prevalence of HIV and its risk factorsin this population. Patients and A total of 228 ISUs were included in this cross-sectional study, which was conducted in Ahvaz, southern Iran, from 2005 to 2006. The study population was randomly selected from available ISUs in prisons and addiction treatment centers. Subjects were tested for the presence of anti-HIV antibodies using the enzyme linked immunosorbent assay (ELISA) method. Drug use behaviors associated with HIV transmission (i.e., high-risk behaviors) and their current sexual risk behaviors were examined. Sixty two (27.2 %; 95 % CI: 22.5 % - 31.8 %) of the 228 men were HIV positive. The prevalence of HIV positivity in injecting, inhalant and oral users was 50.2 %, 10.4 %, and 7.6 %, respectively. HIV was positive in heroin, crack and opium users with a rate of 96.2 %, 83.3 %, and 1.4 %, respectively. Among the HIV infected cases, the vast majority had engaged in high-risk behaviors, including sharing needles (72 %), the majority of the injectors had also had unprotected sex with women (67.7 %), or with men (22.6 %). Illicit substance usage is associated with an increased risk of exposure to HIV and this results in a high prevalence of HIV infection. Heroin injecting, sexually transmitted diseases (STD), having sex with multiple partners, unprotected sex, a long period in prison, early adulthood, and family contact with HIV infected cases, are considered to be the main risk factors for HIV infection.

Toluene which widely exists in petroleum and its related products has gathered much attention due to its adverse effects on health and carcinogenic potential. Since microorganisms are able to utilize petroleum hydrocarbon as carbon and energy sources, they can be used for bioremediation applications. The aim of this study was to isolate toluene degrading bacteria from wastewater and seawater. The production of exopolysaccharide, biosurfactant and peroxidase enzymes such as laccase and catalase were investigated to determine the effect of them on toluene degradation. To screen and isolate toluene degrading bacteria, contaminated seawater and wastewater samples were added to toluene containing mineral media (MM). The biochemical and molecular characteristics of the isolates were then studied. From seawater, two toluene degrading Bacillus and one Sporosacina species and from wastewater a novel high capable toluene degrading strain, Bacterium Ex-DG74 were isolated and introduced. Bacterium Ex-DG74 showed tolerance to 15 % (v/v) toluene but the marine isolated species could tolerate only 1 % (v/v) toluene. This bacterium also showed the highest catalase and membrane-bound laccase activity. The spore-forming marine bacterium, S. halophila produced large amounts of exopolysaccharide, biosurfactant and extracellular laccase. The results of the present research indicated that EPS, biosurfactant and peroxidase enzymes can have essential roles on toluene tolerance and biodegradation. These native microbial isolates could be considered as a powerful approach for the in situ bioremediation of hydrocarbon-contaminated sea and wastewater.

Wild Rats have been implicated as potential reservoirs of Cryptosporidium spp., thereby responsible for transimission of the infection to humans by acting as natural sources of C. parvum, a zoonotic species. Recently, and possibly due to much closer and more frequent contacts to these animals, concerns have raised about spread of the disease among human environments. The purpose of this study is molecular characterization of Cryptosporidium in rats of Tehran. Rats were hunted randomly from different zones of Tehran and their stool samples were studied by Polimerase Chain Reaction (PCR) method using 18s rRNA gene. Subsequently, positive (i.e. infected) samples were characterized and sequenced. Reported rates of Cryptosporidium infection among 77 rats by implementation of staining as well as nested PCR methods were %13 and 27.3 %, respectively. In order to recognize type of infective agent, all positive cases were tested by PCR – RFLP (Restriction Fragment Length Polyformism) method by which C. parvum pattern was obsereved.. The obsereved patten inPCR-RFLP test was checked via sequence determination method in all positive isolations and the results were approved. The results reveal that wild rats in Tehran are reservoirs of C. parvum that could be transmitted to humans. Also, it illuminates hygienic importance of freewildrats eradication throughout the city.

Corneal ulcer is a common cause of blindness in developing countries, as itleads to corneal perforation and blindness if not properly treated. This study aimed to determine the effects of intraocular 5 % and 10 % topical povidone iodine in the treatment of bacterial corneal ulcer in a rabbit model, comparing the effectiveness of vancomycin and cefazolin eye drops. Total of 40 eyes ofrom 20 wild rabbits were randomly assigned to four equal groups, five in each (n = 5), they included; group 1. 5 % povidone iodine and vancomycin; group 2.5 % povidone iodine and cefazolin; group 3.10 % povidone iodine and vancomycin; group 4.10 % povidone iodine and cefazolin (one drop every two hours for seven days and nights). The animals were first anesthetized with ketamine hydrochloride and xylazine chloride. Then, a 27-gauge needle attached to a 1-ml syringe was tunneled through the clear cornea to approximately midstromal depth, stopping at the edge of the 2-mm optical zone. Finally, 0.02 ml of Staphylococcus contaminated media containing about 100 organisms was injected, forming a central intra-stromal infiltrate. There was no statistically significant difference in the density of infiltration, size of infiltration, hypopyon, or fibrin formation between the four groups. However, epithelial defect, stromal edema, conjunctival injection, and chemosis were significantly higher in the 5 % and 10 % povidone iodine groups when compared to the cefazolin and vancomycin groups. Thinning was more common in the cefazolin group. There was one sealed corneal perforation in the cefazolin group at the beginning, and at day 6, one perforation in the cefazolin group and one perforation in the 10 % povidone iodine group also developed. Cefazolin and vancomycin had a superior clinical effect on the staphylococcal corneal ulcers in this study. 5 % and 10 % povidone iodine was toxic to the corneal epithelium. Thinning and perforation was more common with cefazolin.

A variety of agricultural products are exposed to fungal contamination from the early stages of planting, until their final consumption. T-2 mycotoxin is toxic to humans and to all animal species, it is mainly produced by the various Fusarium species including; F. sporotrichioides, F. poae, F equiseti, and F. acuminatum, and occasionally by other genera species, therefore, measuring T-2 toxin levels is very important in cereals. We examined the occurrence and levels of T-2 mycotoxin in grains for human consumption. Rice, barley and wheat samples, 23, 16 and 7 respectively, were collected from the staple stores of nine food cooking centers in Tehran. After pulverizing the samples, they were extracted using a methanol-water solution (70:30), then analysed with an enzyme linked immunosorbent assay (ELISA), based on the monoclonal antibodies, the amount of T-2 mycotoxin was measured in their extracts. All of the tested samples were contaminated with T-2 toxin at different levels ranging from 7.9 to 65.9 μg/kg (mean: 17.9 ± 2.1). Wheat samples had the highest level of contamination at approximately 42.4 μg/kg (± 8.4). However, both barley and rice were also affected with contamination levels of 18.3 (±2) and 12.5 (± 0.56) μg/kg respectively. Although the majority of samples were based on Iranian national standards, a small number of specimens (13.9 %) were contaminated at higher than acceptable limits. The extent of the impurities with T-2 toxin is an indicator of the current normal prevalence of mycotoxins in agricultural products destined for human consumption in this country, and the risk of exposure to the chronic effects of this toxin. Overall, this study showed that the level of mycotoxins in food products should be checked before they are bought or consumed

: IL-2 is a cytokine that plays an active role in the activation and maintenance of both acquired and innate immune defenses. It is also capable of improving the rotective immune responses that are generated by conventional vaccines against avian athogens in the poultry industry when used as an adjuvant. The aim of this study was to extract and sequence Iranian chicken IL-2. In this study, genomic DNA was extracted from Iranian chickens. Total RNA was isolated by culturing harvested splenocytesand lysing them with Trizol reagent per the manufacturer's instructions. mRNA was isolated and converted to cDNA using reverse-transcriptase (RT) and specific designed primers. Then, the PCR product was ligated into the PTZ57R/T plasmid (TA-cloning) and transformed into competent Top10 E. coli cells. A unique 668-bp band was obtained after RT-PCR. Restriction enzyme digestion and colony PCR analysis and direct sequencing confirmed the existence of the desired gene in transformants. For first time in Iran, the chIL-2 gene was successfully extracted, cloned, and ransferred into E. coli. The efficacy of recombinant or DNA vaccines can be modulated by codelivery f this cytokine gene

Infection with metallo-beta-lactamase (MBL)-producing organisms, particularlyPseudomonas aeruginosa, is associated with higher mortality and morbidity rates and health care costs. In this study, we aimed to determine the etiology of burns and the incidence and susceptibility patterns of metallo-beta-lactamase producers among P. aeruginosa samples that were isolated from burn patients in Kurdistan province. Patients and A total of 176 clinical specimens were received for P. aeruginosa testing. Antimicrobial susceptibility testing, determination of MIC, and detection of MBL-producing P. aeruginosa strains were performed per CLSI guidelines. During the study period, 145 burn patients were admitted to the burn unit of Tohid Hospital. Their mean age and total body surface area (TBSA) were 29 years and 37.7 %, respectively. The mean length of hospital stay was 10 days. Kerosene was the most common cause of burns (60 %), followed by gas (30 %). In the 176 clinical specimens from burn patients, 100 P. aeruginosa isolates were identified. The antibiotic to which most bacteria were resistant was ampicillin (100 %), and the most effective antibiotic was meropenem. Of the 100 P. aeruginosa isolates, 22 (22 %) were positive for MBL production, of which 8 were resistant to imipenem. Of all burn injuries, 87 (60 %) patients were caused by kerosene, which is used primarily by people in low-income groups to light lamps. Our results demonstrate the serious threat of the spread of metallo-beta-lactamase producers; thus, systematic surveillance for detecting MBL producers is necessary.

Several medicinal plants have been used by humans for their vast diversity in chemical compound content and antimicrobial activity. However, their appropriate use remains under investigation by many researchers. This study aimed to determine the stage at which Escherichia coli O157 growth is more sensitive to certain concentrations of certain medicinal plants. Alcoholic extracts of the aerial parts and seeds of Peganum harmala and Teucrium polium were prepared using standard methods. The effective concentration (0.15-0.4 mg/ml) was chosen, based on their zones of inhibition on plates that were inoculated with E. coli O157 and plant extract and used to monitor bacterial growth by spectrophotometry. All concentrations of the aerial parts of T. polium extract and the seeds of P. harmala decreased the absorbance in the first several hours after inoculation, after which bacterial growth increased to normal levels. Compared with control, no significant differences on the effect of the aerial parts of P. harmala extract on bacterial growth were observed. Based on the comparison of growth curves, higher concentrations effected greater inhibition. However, the effects of other concentrations of the plant extracts on bacterial growth should be investigated further, although their toxicity must be assessed before use.

Pulmonary embolism is the fourth leading cause of pleural effusion. Pleural effusion that results from a pulmonary embolus is usually small and unilateral. A pulmonary embolus is the most common cause of pleuritic chest pain and pleural effusion in patients aged under 40 years. The incidence, characteristics, and pathogenesis of pleural effusions in patients with right-sided endocarditis (RSE) are poorly defined. Possible mechanisms of pleural fluid formation in RSE include parapneumonic effusion, septic pulmonary emboli with or without infarction, and empyema. We report 2 cases of bloody pleural effusion, combined with septic pulmonary emboli and dyspnea, as the initial manifestation of right-sided endocarditis.