Iranian Journal of Microbiology
Year:2016 | Volume:8 | Issue:6|Papers Count:10

Background and Objectives: Secreted Aspartyl Proteinase (SAP) is one of the main virulence factors in the pathogenesis ofCandida. This enzyme is encoded by a family of at least ten genes. Among these genes, the role of SAP1-3 in mucosal infectionsis evident. This study aimed to investigate the expression of SAP1-3 genes of Candida albicans isolates after treatmentwith Echinophora platyloba extract, carvacrol and caspofungin drug.Materials and Methods: Vaginal samples of 68 women with suspected vaginitis were obtained and cultured. Canida albicansspecies were identified using phenotypic and genotyping methods. Spectrophotometry was used to investigate thepresence of SAP protein in the vaginal samples, and SDS-PAGE was used to confirm its protein composition. Real-timePCR was performed to ascertain the effects of subinhibitory concentrations of Echinophora platyloba extract, carvacrol andcaspofungin on the expression of SAP1-3 genes before and after treatment.Results: C. albicans was found as the abundant species (59.6%), and different amounts of SAP were present in all vaginalsamples, which were higher than Candida krusei strain. The protein composition of SAP in C. albicans samples was estimatedwith the approximate molecular weight of 45 kDa. mRNA levels of total SAP in FLU-resistant isolates (P=0.01) were morethan those of FLU-susceptible isolates (P=0.07). The findings indicated that carvacrol is effective in reduction of SAP1-3expression with a particular effect against FLU-resistant isolates.Conclusion: Carvacrol contains an essential oil (carvacrol); therefore, it can be considered as an alternative effective antifungalcompound.

Background and Objectives: Antibiotic therapy is the main choice in treatment of Escherichia coli induced infections.Using herbal medication is an alternative choice in treatment of diseases. The aim of this study was to determine the antibacterialactivity of two traditionally used herbs in Iranian medicine, Anacyclus pyrethrum and Pistacia lentiscus L., onEscherichia coli.Materials and Methods: The antibacterial effect of methanolic extract of Anacyclus pyrethrum and Pistacia lentiscus L.were examined in disk diffusion and skipped wells methods by measuring the diameter of inhibition zones around wellscontaining different concentrations of extracts from (10-1000 mg/ml) using standard broth macrodilution, method the MICand MBC were defined.Results: The methanolic extract of Anacyclus pyrethrum from 300 to 1000 mg/ml and the methanolic extract of Pistacialentiscus L. from 30 to 1000 mg/ml showed antibacterial activity on Escherichia coli. The MIC of Anacyclus pyrethrum andPistacia lentiscus L. methanolic based extract were 800 and 1000 mg/ml, respectively. The MBC was achieved at 800 mg/ml for methanolic extract of Anacyclus pyrethrum and Pistacia lentiscus L.Conclusion: The methanolic extract of Anacyclus pyrethrum and Pistacia lentiscus L. have antibacterial effect on Escherichiacoli bacteria. This activity is dose-dependent.

Background and Objectives: Diarrheagenic Escherichia coli (DEC) is an emerging agent among pathogens that causesdiarrhea. Studies showed that diarrheagenic E. coli such as enterohaemorrhagic E. coli (EHEC), enteroaggregative E. coli(EAEC), enteropathogenic E. coli (EPEC), enteroinvasive E. coli (EIEC), enterotoxigenic E. coli (ETEC), diffusely adheringE. coli (DAEC) and shiga toxin producing E. coli (STEC) strains are among the most frequent causative agents in acutediarrhea. The aim of this study was to determine the frequency of DEC pathotypes in Khuzestan province.Materials and Methods: Stool samples were collected from patients with diarrhea in Khuzestan province of Iran. E. colistrains were isolated using conventional culture and standard biochemical tests. The polymerase chain reaction (PCR) techniquewas used to detect presence of virulence genes, i.e; eae, stx1 and stx2 for EHEC, bfp and eae for EPEC, LT and ST forETEC, AA for EAEC, invE for EIEC, stx1 and stx2 for STEC.Results: Altogether, 200 stool samples were obtained from patients, of which 158 (79%) were positive for E. coli. DEC wasidentified in 127 (63%) of stool samples, which frequency of each pathotypes were as follows: atypical EPEC 49 (39%), typical EPEC 1 (0.7%), STEC 50 (39.3%), ETEC 21 (16.3%), EAEC 5 (4.0%) and EIEC 1 (0.7%). Most frequent etiologicalagents of diarrhea in Khuzestan province of Iran were STEC and EPEC.Conclusion: Our findings showed DEC had been agent of diarrhea in Khuzestan. This finding provides evidence that effortshould be made to estimate the burden of infection by the etiological agent for better medical approach and should raisenotification about antibiotic resistance among bacterial infection.

Background and Objectives: Bacteria need iron for growth and most of them can actively acquire Fe ions using especialiron-chelating proteins which named siderophores. We aimed to determine the frequencies of iucA, iroN and irp2 genes in theuropathogenic Escherichia coli (UPEC) isolates. We also analyzed the effects of siderophore genes beside iron supplementson growth rate of the isolates.Materials and Methods: Totally, 170 E. coli strains were isolated from urinary tract infections and the presence of 3 siderophoregenes were analyzed using PCR among them. Three final concentrations of 0.1, 0.5 and 1 mMFe (II) and Fe (III)ions were made in M9 broth medium. Inoculated cultures were incubated at 37°C for 33 hours and bacterial density in thesuspension was measured with 1 hour intervals using spectrophotometer.Results: The frequency of iucA, iroN and irp2 genes among 170 UPEC isolates were 29 (17.1%), 52 (30.6%) and 116(68.2%), respectively. In addition, Our findings showed that Fe (II) supplements had significantly higher promoting effectson UPEC growth rate almost in all of the three applied concentrations (0.1, 0.5 and 1 mM) compared to the control group(P<0.0001). Differences between Fe (III) supplemented groups and the controls were statistically significant when 1 mMconcentration was added into the medium (p<0.05).Conclusion: irp2 gene probably plays a major role in the pathogenesis of UPEC strains. Promoting or inhibitory effects ofiron on bacterial growth mainly depend on the iron concentration in the culture medium however different siderophores havedifferent potentials for capturing and assimilation of Fe ions by the bacteria, especially inside the host cell.

Background and Objectives: Coagulase negative Staphylococcus (CoNS) is frequently isolated from blood cultures buttheir significance is difficult to interpret. CoNS bacteria which are often previously dismissed as culture contaminants are attractinggreater importance as true pathogens in the past decades. Clinical evaluation of these isolates suggests that althoughthere is a relative increase of CoNS associated bloodstream infections in recent years, the microorganisms still remain themost common contaminants in blood cultures. The objective of this study was to determine the significance of CoNS isolatedfrom blood cultures.Materials and Methods: A retrospective study was conducted to evaluate the rate of contamination in blood cultures in atertiary care hospital. The paired specimens of blood were cultured using conventional culture methods and the isolates ofcoagulase negative staphylococci were identified by standard methodology. Clinical data, laboratory indices, microbiologicalparameters and patient characteristics were analyzed.Results: Of 3503 blood samples, CoNS were isolated from blood culture of 307 patients (8.76%). The isolates were reportedas true pathogens of bloodstream infections in only 74 out of 307 cases (24.1%). In the vast majority, 212 of 307 (69.0%), they were mere blood culture contaminants and reported as insignificant/contaminant.Conclusion: Determining whether a growth in the blood culture is a pathogen or a contaminant is a critical issue and multipleparameters have to be considered before arriving at a conclusion. Ideally, the molecular approach is for the most part aconsistent method in determining the significant isolates of CoNS. However, in countries with inadequate resources, speciesidentification and antibiogram tests are recommended when determining significance of these isolates.

Background and Objectives: Phosphorus is one of the low bioavailable macroelements. Use of microorganisms in biofertilizerscould release phosphorus from insoluble compounds. Pseudomonas putida P13 and Pantoea agglomerans P5 are wellrecognized for application as phosphate solubilizing bioinoculants and are used as solid carrier based. Liquid bioinoculantsare preferred for economizing production process and longer shelf-life.Materials and Methods: Five low cost liquid formulations were examined. Formulations 1, 2 and 3, were phosphate buffer, 0.2% and 0.5% KNO3 dissolved in phosphate buffer, respectively. Formulation 4 was nutrient broth containing 4% glyceroland formulation 5 was diluted nutrient broth containing 4% glycerol. Survival (cfu) and phosphate solubilization index (SI)were evaluated after 3 months.Results: Considering strain P5, increase in KNO3 concentration decreased preserving ability. While using KNO3 at 0.2% wasaccompanied with reaching maximum SI level. Overall, less nutritious formulations (1 and 5) provided maximum preservingability without bioactivity loss. In the case of strain P13, maximum survival obtained in formulations 2 and 3, whereas SIlevel decreased. Preserving ability in formulations 1, 4 and 5 was similar but less nutritious formulations (1 and 5), improvedbioactivity.Conclusion: The results introduced two formulations of 1 and 5 as economically efficient liquid bioinoculants for Pseudomonasputida and Pantoea agglomerans.

Background and Objectives: Association between Mycoplasma pneumoniae infection and increased risk for brain strokehas been well understood. Hence, the value of serologic tests for assessing causative relationship between this infection andbrain stroke seems to be high. The present study aimed to determine serum level of anti-Mycoplasma pneumoniae antibodiesin patients with brain stroke and to compare it with non-stroke patients.Materials and Methods: This cross-sectional study was performed on 97 consecutive ischemic stroke patients and 97 sexand age-matched non-stroke patients. Quantitative enzyme-linked immunosorbent assay (ELISA) was established to measurethe levels of anti-Mycoplasma pneumoniae IgG and IgM antibodies.Results: Regarding the level of anti-Mycoplasma pneumoniae IgM, the titer of this marker was positive in 4.1% of patientswith ischemic stroke, while none of the subjects in control group had positive titer for this antibody (OR=1.043, 95%CI: 1.001 – 1.087, p=0.043). The rate of positivity for anti-Mycoplasma pneumoniae IgG in ischemic stroke patients was significantlyhigher than in the control group (28.5% versus 13.4%, p=0.031). Odds ratio for exposure to M. pneumoniae was 2.24times of the control subjects. The level of anti-Mycoplasma pneumoniae IgM was independent to both sex and age variablesin patients group (p=0.77). The level of anti-Mycoplasma pneumoniae IgG did not depend on subjects’ gender in controlgroup, but was significantly higher in men compared with women in patients group.Conclusion: A high level of anti-Mycoplasma pneumoniae IgM and IgG antibodies indicate a significant association of M.pneumoniae infection and history of this infection with increased risk for ischemic stroke.

Background and Objectives: Hepatitis C virus (HCV) is a major public health problem worldwide. Replication and persistenceof HCV genome have been described in the liver tissue as well as B cells lymphocyte. Several investigations havereported that long-term persistence of HCV in B cells may result in Hodgkin and Non-Hodgkin lymphoma. This studywas aimed to determine frequency of HCV RNA in histological tissues obtained from patients suffered from Hodgkin andNon-Hodgkin lymphoma.Materials and Methods: 52 formalin-fixed paraffin-embedded tissue blocks including 23 (44.3%) Hodgkin and 29 (55.7%)Non-Hodgkin samples were collected and five micrometer sections were prepared. RNA was extracted and cDNA was synthesized.Two consecutive Nested RT-PCR assays were carried out for detection of HCV 5’ UTR and core gene. RT-PCRproducts were sequenced and aligned to construct HCV phylogenic tree to evaluate the homology of sequences in comparisonto the reference sequences retrieved from Genbank.Results: Overall, 6 Non-Hodgkin (20.6%) and 3 Hodgkin lymphoma (13.04%) samples showed positive PCR results forboth 5’ UTR and HCV core RNA via nested PCR (P<0.469). Sequencing results revealed that all detected HCV RNA samplesbelonged to the genotype 3a.Conclusion: Despite low prevalence of HCV infection in Iran, high frequency of HCV RNA genotypes 3a (17.3%) has beenfound in patients with Hodgkin and Non-Hodgkin lymphoma. To improve treatment regimens, screening of HCV RNA inpatients suffered from Hodgkin or Non-Hodgkin lymphoma is recommended which can be done through highly sensitivemolecular means before and after immunosuppression status.

Background and Objectives: A single reactive IgG anti-Dengue virus ELISA test in the absence of IgM antibodies or NS1antigen may denote current infection or past exposure to the virus. To determine whether IgG index value can be used toidentify true current dengue infection we conducted a prospective observational study.Materials and Methods: Suspected dengue patients (n=1745) were tested in their first specimen by MAC-ELISA, GAC-ELISA and NS1 antigen ELISA. Patients with MAC-ELISA and NS1Antigen non-reactive but GAC-ELISA reactiveresults (n=57) in their first test were followed up and repeated sampling was asked for IgG index values were calculatedaccording to the manufacturer’s instruction and classified as: low (2.2-2.5), medium (2.5-4.0) and high (>4.0).Results: 16 out of 57 patients (28.1%) had low IgG Index value whereas 26 cases (45.6%) were categorized as medium and15 (26.3%) were classified as patients with high IgG index. Nine patients with paired reactive serology or antigen positivestatus were categorised as serologically confirmed dengue fever, 11 patients as not dengue with categorical evidence of otherinfections while the rest 37 casas with clinical, radiological and laboratory parameters suggestive of dengue but no serologicalconfirmation as possible dengue. Among confirmed, possible and non-Dengue cases, 33.3, 32.4 and 0.0% had high Indexvalue in comparison with 22.2, 29.7 and 27.3% showing low Index values, respectively.Conclusion: Our results suggested a high IgG response in favour of true dengue infection than past exposure while no conclusionsshould drawn from a low or medium reactive GAC-ELISA results in the absence of IgM antibodies and NS1 Ag.

Background and Objectives: Vulvovaginal candidiasis is a common fungal infection among women during reproductiveages. Although, Candida albicans is accounted as the main etiologic agent of vaginitis, non-albicans species have arisenduring last years. Resistant to antifungal drugs especially, fluconazole has been more reported by researchers from aroundthe World. The aims of this study were to determine the prevalence of vulvovaginal candidiasis among suspected patientswith vaginitis, the frequency of Candida species, and the susceptibility profiles of isolates to caspofungin, fluconazole andclotrimazole.Materials and Methods: One hundred and twenty suspected women with vaginitis were examined by specialist physicianand sampled using moisture swabs. Swabs were inoculated on CHROMagar Candida plates, incubated at 35ºC and detectedall isolated Candida species using morphological, microcopy and molecular methods. The antifungal susceptibility tests withcaspofungin, fluconazole and clotrimazole were applied using microdilution and Resazurin dye methods against all isolatedyeasts.Results: The cultures were positive for 34 (28.3%) samples and three Candida species including; C. albicans (88.2%), C.glabrata (8.8%) and C. kefyr (2.9%). Our study shows that only one isolate of C. albicans was resistant to caspofungin at theconcentration of 2 μg/ml after 24h incubation that increased to 2 isolates after 48h incubation. All isolates were sensitive tofluconazole at the MIC ranges of 1-0.25 μg/ml, while 88.2% of them were inhibited at 0.25 μg/mL of clotrimazole. Candidaalbicans remains the most common agent of fungal vaginitis.Conclusion: Although all of Candida isolates were susceptible to fluconazole in vitro, it should be used with caution for empiricaltherapy due to more resistant rates in clinic. In addition, due to valuable sensitivity of all tested strains to caspofungin, it potentially can be presented as the first line therapy for Candida vaginitis.