Jundishapur Journal of Microbiology
Volume:5 Issue: 1, Jan 2012

For more than 2 decades, human immunodeficiency virus (HIV) infectionhas been known to cause significant morbidity and mortality. Difficulties in treatingHIV-infected patients include adverse effects and drug resistance and continue to limitthe use of conventional anti-retroviral therapies. To find new anti-retroviral drugs from natural sources, we investigated theinhibitory effects and mechanism of action of HESA-A, a natural biological compound ofherbal-marine origin, against HIV-1 replication in vitro. In this study, we used a single-cycle replicable HIV-1 system inwhich co-transfection of human embryonic kidney (HEK)-293T cells with pmzNL4-3,psPAX2, and pM2G.2 plasmids was performed. Cytotoxicity and cytopathic protectionassays were performed using the 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-(2H)-tetrazolium-5-carboxanilide method. Inhibition of p24 antigen production was analyzed, andtime-of-drug-addition assay was conducted using quantitative enzyme-linked immunosorbentassay (ELISA). HESA-A inhibited HIV-1-induced cytopathic effect in MT2 and HEK293T cells, andthe selectivity index values were 13.3 and 8, respectively. We performed quantitative p24ELISA and added varying concentrations of HESA-A in cell culture supernatants at differenttimes; we observed that HESA-A preserved its ability to inhibit viral replication evenat 12 h post-infection. These results suggest that HESA-A has potent anti-HIV activity, and its mechanismof action likely involves interference during the late stages of viral replication,such as virus maturation.

American cockroaches are found in association with human dwellings andhospitals. They have a worldwide distribution. These domestic pests affect human healthin several ways. Their habits make them ideal mechanical carriers of different pathogenicmicroorganisms. Numerous bacteria of medical importance have been isolated fromcockroaches. The objective of this research was to determine the role of American cockroachesas carriers of pathogenic bacteria. This was accomplished through the isolationand identification of these microorganisms from the external surfaces of cockroachescaptured in Health and Medical Services Centers and their surroundings. Seventy-three cockroaches were caught in Health and MedicalServices Centers in Khorramshahr County, southwestern Iran, in 2006. The fluid used towash the external surfaces of cockroaches was cultured to isolate and identify bacterialpathogens. Pathogenic bacteria were isolated from the external surfaces of 100% of the Americancockroaches examined. The following bacterial pathogens were recovered fromtheir body surface:Klebsiella (47.9%), Pseudomonas (37%), Escherichia coli (30.1%), Staphylococcus(24.6%), Enterobacter (19.2%), Streptococcus (15.1%), Serratia (8.2%), Bacillus (4.1%), andProteus (2.7%). The bacterial pathogenic flora isolated from this cockroach species indicatethat domestic pests could pose a health problem to humans. Thus, we must control cockroaches,particularly in indoors, sewage and solid wastes.

Asymptomatic bacteriuria can develop into symptomatic urinary tract infection. This study investigated asymptomatic Escherichia coli bacteriuria among undergraduatestudents of Nasarawa State University, Keffi, Nigeria, and the antimicrobialsusceptibility of bacterial isolates from these subjects.Patients and Four hundred urine samples were collected from consentinghealthy male and female students. The bacterial load of each sample was determined byspread plate count on nutrient agar. E. coli was isolated and antimicrobial susceptibilityof the isolates to common antibiotics was evaluated by the disc-diffusion method. Of the urine samples, 80 (20%) showed significant bacteriuria, with a higherprevalence in females (25%) than in males (15%). While 60% of E. coli isolates from malesamples were susceptible to pefloxacin or gentamicin, 3.3% were susceptible to amoxicillin/clavulanic acid. Twenty-seven (90%) E. coli isolates from male samples had multipleantibiotic resistance (MAR), with 37% being resistant to 5 antibiotics and possessing MARindices of 0.5. Forty-nine (98%) of the E. coli isolates from female samples had MAR, with13 (26.5%) being resistant to 6 antimicrobial agents and possessing MAR indices of 0.6. Significant bacteriuria is observed among the students of Nasarawa StateUniversity, with a higher prevalence in females than in males. Pefloxacin, ofloxacin, andgentamicin are effective against E. coli isolates from the urine of these students.

Staphylococcus aureus is the causative agent of a high percentage of nosocomiallyacquired infections and food-borne illnesses. Antimicrobial resistance of S. aureus,especially methicillin-resistant S. aureus (MRSA), continues to be a concernfor cliniciansworldwide. The aim of this study was to investigate the effects of salt stress on the antimicrobialdrug resistance and protein profile of S. aureus. Staphylococcus aureus (ATCC 25823) was grown in trypticase soybroth at 37°C. Cells in the exponential growth phase were gradually exposed to sub-lethalsalt stress with concentrations ranging from 5% to35% (wt/vol). There after, these cells wereharvested and re-suspended in a tube containing 0.5mL of saline. To standardize the numberof bacteria, the bacterial suspension was compared to the 0.5 McFarland standard suspension.Antibiotic susceptibility was determined using the disk diffusion method, andthe method involved plating of cell suspensions with stressed cells and unstressed cells onMueller-Hinton agar plates. The pooled proteins from each condition were analyzed usingsodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Compared to the unstressed cells, the cells exposed to salt showed significantchanges in resistance to rifampicin (P=0.032), penicillin (P=0.02) and methicillin(P=0.001). Furthermore, SDS-PAGE analysis of pooled proteins from cells exposed to saltshowed changes in the protein profile. We conclude that salt stress is responsible for the changes in protein profileandantimicrobial resistance of S. aureus, especially to methicillin.

The protist pathogen Toxoplasma gondii infects humans and other animalssuch as wild rats (Rattus rattus) worldwide. Wild rats are infected with T. gondii due toingestion of food or water contaminated with oocysts and may play an important role inthe transmission of T. gondii infection to humans. The aim of the present study was to determine the seroprevalence of T. gondiiamong wild rats in Ahvaz district, southwestern Iran. We determined the seroprevalence of T. gondii among wild rats(R. rattus) in Ahvaz district between February 2008 and January 2011. Immunochromatographicassay (ICA) to detect serum antibodies against T. gondii was performed for 127adult wild rats. The rats were captured in cages and brought alive to the Veterinary Hospitalof Shahid Chamran University. The rats were classified according to sex and seasonand region of capture. The results were analyzed by Chi-square analysis and Fisher’s exacttest. Thirty-one of the 127 serum samples (24.41%) had antibodies against T. gondii (95%Confidence interval; 16.9–31.9%). Prevalence was higher in female rats (24.66%) than inmale rats (24.07%). The rats caught during summer (34.48%) and in the east region ofAhvaz district (36.36%) showed high prevalence. However, the gender, season and regionof collection did not significantly affect the prevalence of infection (P > 0.05). Our study showed that the seroprevalence of T. gondii was relatively high(24.41%) among wild rats in the Ahvaz district of Iran. The high prevalence of T. gondiiinfection in rodents may be of epidemiological importance as infected rodents are a potentialroute for T. gondii transmission to Felidae via ingestion of tissue cysts.

The incidence of opportunistic infections due to Candida albicans and otherCandida spp. has been increasing. Rapid identification of candidiasis is important forthe clinical management of immunocompromised patients. Polymerase chain reactionrestrictionfragment length polymorphism (PCR-RFLP) is a rapid, sensitive, and specificmethod for detection of clinically important fungi. The purpose of this study was to identify Candida spp. isolated from the oralcavities of HIV-infected patients in southeastern Iran (Kerman), by using PCR-based restrictionenzyme digestion.Patients and We identified 96 Candida isolates obtained from 139 Iranian patientsinfected with the human immunodeficiency virus (HIV), between April 2009 andApril 2010, by using PCR-RFLP assay. Universal primers for the internal transcribed spacer(ITS) region (ITS1–ITS4) of the fungal rRNA genes were used for this assay. We successfully identified the different Candida spp. by using the restriction enzymeMspI. C. albicans was the most commonly identified species (82.2%), followed by C.glabrata (7.29%), C. parapsilosis and C. kefyr (both 4.1%), and C. tropicalis (2%). PCR-RFLP is a highly sensitive, specific, and direct method for fungal detectionand can be used for fungal epidemiological studies in HIV-positive and other immunocompromisedpatients.

Emerging antibiotic resistance in pathogenic bacteria has driven the developmentof new assays for routine antibiotic testing. The purpose of this study was to evaluate the effects of different organic solventsin preparing two-fold decreases in serial penicillin concentration coated onto 96-well platesto design a method for antibiotic susceptibility testing. Benzyl penicillin was dissolved in each solvent (sterile distilled water,PBS, diethyl alcohol, ethanol, butanol, chloroform, 2-propanol, and acetonitrile). Serial dilutionsof each solution were loaded onto a 96-well microtiter plate and incubated at 37°C for12 h. Next, 200 μL of sterilized Mueller-Hinton broth was added along with 50 μL of bacterialsuspension at an adjusted concentration equivalent to 0.5 McFarland standards. The preparedplates were incubated at 37ºC for 24 h. Optical density (OD) was measured at 540 nm. When comparing the ODs of each sample in 96-well microtiter plates with positiveand negative controls, significant antibacterial activity was observed. Most activities rangedfrom 50 to 200 units of penicillin in samples that were diluted with distilled water, PBS, orisobutyl alcohol as a solvent. Analysis of the results suggested that, when using the aforementionedsolvents, the minimum inhibitory concentration of penicillin against a sensitivestrain of Staphylococcus aureus was ≥50 units of penicillin. The results revealed that the accuracy and feasibility of this method can greatlyreduce the waiting period of antibacterial sensitivity tests. Additionally, this method is lowcostand could benefit patients who urgently require proper antibiotic therapy.

Some species of yeast such as Yarrowia lipolytica produce citric acid, lipases,single-cell oil, etc. Y. lipolytica can degrade renewable, low-cost substrates to produce organicacids like citric acid, more efficiently than Aspergillus niger, and result in higherproduct yield and lesser waste production and toxicity. The aim of this study was to isolate yeast strains with potential for use in biotechnologicalapplications such as production of citric acid and lipase. For yeast strain screening, we isolated 179 yeast strains from meatand meat products that were prepared at the RAK and Pegah factories in Isfahan, Iran. Differentmedia were used for screening of yeast colonies and for analyses of citric acid andlipase production; the production of these metabolites was assayed over time. One of the yeast strains isolated from poultry produced 55.5 g/L of citric acid and12.3 U/mL of lipase. Biochemical and molecular tests showed that this strain belonged tothe species Y. lipolytica. Molecular identification was confirmed by DNA sequencing, andthe strain was named Y. lipolytica M7 (GenBank accession number, HM011048). The results of this study suggest that meat and its products, especially poultryproducts, are suitable sources for isolation of yeast strains that produce two biotechnologicallyvaluable products—citric acid and lipase. The yeast strain Y. lipolytica M7 canbe used for citric acid production in bioreactor.

Acute gastroenteritis, which is one of the most common diseases in humans,isresponsible for many illnesses in both children and adults. Group A rotaviruses are consideredthe main agents of gastroenteritis, and these are followed by calciviruses, adenoviruses,and astroviruses. The aim of this study was to determine the rate of astrovirus and rotavirus coinfectionamong children up to 5 years of age who had gastroenteritis and who were referred toAhvaz Aboozar Hospital.Patients and A total of 180 stool specimens, which were collected from childrenwith gastroenteritis who were less than 5 years old and who were referred to Ahvaz AboozarHospital, were tested by enzyme-linked immunosorbent assay methods for the detection ofrotavirus infections. Detection of astroviruses in positive rotavirus stool specimens was performedby reverse transcriptase-polymerase chain reaction (RT-PCR) methods. Fifty-nine of the 180 samples were positive for rotavirus infection. These positivesamples were subjected to RT-PCR to test forastrovirus. After RT-PCR with specific astrovirusprimer sets, 8 samples were positive for astrovirus as well. Therefore, 13% of rotavirus-positivesamples were also positive for astrovirus. Group A rotaviruses, in addition tocalciviruses, adenoviruses, and astroviruses,can cause acute gastroenteritis. Studies have shown that 2.5 million deaths occur every yearfrom gastroenteritis. In this study, we found that the prevalence of rotavirus infections wasvery high and that of coinfections of rotavirus and astrovirus were considerable. In order toreduce the risk of infections and to eliminate viral gastroenteritis in this zone of the region,education, vaccinations, and improved personal hygiene must be improved.

Noroviruses belong to the Norovirus genus in the Caliciviridae family. Norovirusesare the most common causes of gastroenteritis and have a great impact on publichealth. They have been identified as a common cause of acute gastroenteritis in children. The aim of this study was to determine the prevalence of Norovirus in childrensuffering from gastroenteritis.Patients and Fecal samples (n = 143) were collected from children under 5 years ofage who were suffering from gastroenteritis. All the children were referred to Ahvaz AboozarHospital, located in southwestern Iran. Norovirus RNA was extracted by Trizol, andRNA was detected using nested reverse transcriptase polymerase chain reaction (nested-RT-PCR). Norovirus infection was detected in 9 of the 143 collected samples (6.3%). All positivesamples belonged to genogroup II. Five positive samples were obtained from malepatients and 4 were obtained from female patients. Most of the positive cases were frompatients between 3 and 5 yars of age (n = 5, 56%). There was no relationship between genderand virus prevalence. The rate of infection peaked in winter (n =6, 66.9%), and we did notdetect any positive cases in summer. The prevalence of this virus in Ahvaz is similar to that reported by other researchers.Because this virus is transmitted by contaminated food or water, we recommendadult education and improved personal hygiene to reduce the incidence of Norovirusinfection in children. This study improves our epidemiological knowledge of theprevalence of this virus in Ahvaz and Iran.

Gastroenteritis is a common cause of morbidity and mortality in humans allover the world, especially in infants under 5 years of age. Many microorganisms, includingviruses, have been identified as the causative agents of gastroenteritis. Sapovirus is a majorcausative agent of acute viral diarrhea that occurs mostly in children under 5 years of age. The aim of this study was to determine the prevalence of Sapovirus infectionamong children under 5 years of age who had gastroenteritis and were referred to AboozarHospital, Ahvaz, Iran.Patients and All fecal specimens were collected from children with acute gastroenteritis,Sapovirus RNA was extracted using TRIzol and detected by reverse transcriptasepolymerasechain reaction (RT-PCR) followed by sequencing of the positive samples. Of the 200 clinical stool samples collected, 6 (3%; 5 samples from male patients and1 from a female patient) were found to be positive for Sapovirus by the RT-PCR method.The identityof the PCR products was confirmed by sequencing. Sapoviruses belonging togenogroup II were identified as the dominant type causing gastroenteritis in children. Theincidence of Sapovirus infection was the highest during the coldest months. Sapovirus prevalence in children under the age of 5 years with acute gastroenteritiswas 3%, and genogroup ІІ was the dominant type.

We report the first case of Microsporum persicolor being isolated from an Iranian patient.An 8-year-old girl was examined for tinea corporis. Microscopic examination of the skinscraping performed using 15% KOH revealed hyaline septate branching mycelium andarthroconidia. Cultures of the clinical material yielded M. persicolor after 2 weeks of incubation.The isolate was identified on the basis of gross morphological characteristicsof the fungal colony on Mycobiotic agar and peptone agar, microscopic characterizationof slide culture, and biochemical reactions.