Iranian Journal of Microbiology
Volume:8 Issue: 6, Dec 2016

Diarrheagenic Escherichia coli (DEC) is an emerging agent among pathogens that causes diarrhea. 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 adhering E. coli (DAEC) and shiga toxin producing E. coli (STEC) strains are among the most frequent causative agents in acute diarrhea. The aim of this study was to determine the frequency of DEC pathotypes in Khuzestan province.
Stool samples were collected from patients with diarrhea in Khuzestan province of Iran. E. coli strains were isolated using conventional culture and standard biochemical tests. The polymerase chain reaction (PCR) technique was used to detect presence of virulence genes, i.e; eae, stx1 and stx2 for EHEC, bfp and eae for EPEC, LT and ST for ETEC, AA for EAEC, invE for EIEC, stx1 and stx2 for STEC.
Altogether, 200 stool samples were obtained from patients, of which 158 (79%) were positive for E. coli. DEC was identified 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 etiological agents of diarrhea in Khuzestan province of Iran were STEC and EPEC.
Our findings showed DEC had been agent of diarrhea in Khuzestan. This finding provides evidence that effort should be made to estimate the burden of infection by the etiological agent for better medical approach and should raise notification about antibiotic resistance among bacterial infection.

Bacteria need iron for growth and most of them can actively acquire Fe ions using especial iron-chelating proteins which named siderophores. We aimed to determine the frequencies of iucA, iroN and irp2 genes in the uropathogenic Escherichia coli (UPEC) isolates. We also analyzed the effects of siderophore genes beside iron supplements on growth rate of the isolates.
Totally, 170 E. coli strains were isolated from urinary tract infections and the presence of 3 siderophore genes 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 the suspension was measured with 1 hour intervals using spectrophotometer.
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 effects on UPEC growth rate almost in all of the three applied concentrations (0.1, 0.5 and 1 mM) compared to the control group (P irp2 gene probably plays a major role in the pathogenesis of UPEC strains. Promoting or inhibitory effects of iron on bacterial growth mainly depend on the iron concentration in the culture medium however different siderophores have different potentials for capturing and assimilation of Fe ions by the bacteria, especially inside the host cell.

Coagulase negative Staphylococcus (CoNS) is frequently isolated from blood cultures but their significance is difficult to interpret. CoNS bacteria which are often previously dismissed as culture contaminants are attracting greater importance as true pathogens in the past decades. Clinical evaluation of these isolates suggests that although there is a relative increase of CoNS associated bloodstream infections in recent years, the microorganisms still remain the most common contaminants in blood cultures. The objective of this study was to determine the significance of CoNS isolated from blood cultures.
A retrospective study was conducted to evaluate the rate of contamination in blood cultures in a tertiary care hospital. The paired specimens of blood were cultured using conventional culture methods and the isolates of coagulase negative staphylococci were identified by standard methodology. Clinical data, laboratory indices, microbiological parameters and patient characteristics were analyzed.
Of 3503 blood samples, CoNS were isolated from blood culture of 307 patients (8.76%). The isolates were reported as 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.
Determining whether a growth in the blood culture is a pathogen or a contaminant is a critical issue and multiple parameters have to be considered before arriving at a conclusion. Ideally, the molecular approach is for the most part a consistent method in determining the significant isolates of CoNS. However, in countries with inadequate resources, species identification and antibiogram tests are recommended when determining significance of these isolates.

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 antibacterial activity of two traditionally used herbs in Iranian medicine, Anacyclus pyrethrum and Pistacia lentiscus L., on Escherichia coli.
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 wells containing different concentrations of extracts from (10-1000 mg/ml) using standard broth macrodilution, method the MIC and MBC were defined.
The methanolic extract of Anacyclus pyrethrum from 300 to 1000 mg/ml and the methanolic extract of Pistacia lentiscus L. from 30 to 1000 mg/ml showed antibacterial activity on Escherichia coli. The MIC of Anacyclus pyrethrum and Pistacia 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.
The methanolic extract of Anacyclus pyrethrum and Pistacia lentiscus L. have antibacterial effect on Escherichia coli bacteria. This activity is dose-dependent.

Phosphorus is one of the low bioavailable macroelements. Use of microorganisms in biofertilizers could release phosphorus from insoluble compounds. Pseudomonas putida P13 and Pantoea agglomerans P5 are well recognized for application as phosphate solubilizing bioinoculants and are used as solid carrier based. Liquid bioinoculants are preferred for economizing production process and longer shelf-life.
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% glycerol and formulation 5 was diluted nutrient broth containing 4% glycerol. Survival (cfu) and phosphate solubilization index (SI) were evaluated after 3 months.
Considering strain P5, increase in KNO3 concentration decreased preserving ability. While using KNO3 at 0.2% was accompanied with reaching maximum SI level. Overall, less nutritious formulations (1 and 5) provided maximum preserving ability without bioactivity loss. In the case of strain P13, maximum survival obtained in formulations 2 and 3, whereas SI level decreased. Preserving ability in formulations 1, 4 and 5 was similar but less nutritious formulations (1 and 5), improved bioactivity.
The results introduced two formulations of 1 and 5 as economically efficient liquid bioinoculants for Pseudomonas putida and Pantoea agglomerans.

Association between Mycoplasma pneumoniae infection and increased risk for brain stroke has been well understood. Hence, the value of serologic tests for assessing causative relationship between this infection and brain stroke seems to be high. The present study aimed to determine serum level of anti-Mycoplasma pneumoniae antibodies in patients with brain stroke and to compare it with non-stroke patients.
This cross-sectional study was performed on 97 consecutive ischemic stroke patients and 97 sex and age-matched non-stroke patients. Quantitative enzyme-linked immunosorbent assay (ELISA) was established to measure the levels of anti-Mycoplasma pneumoniae IgG and IgM antibodies.
Regarding the level of anti-Mycoplasma pneumoniae IgM, the titer of this marker was positive in 4.1% of patients with 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 significantly higher than in the control group (28.5% versus 13.4%, p = 0.031). Odds ratio for exposure to M. pneumoniae was 2.24 times of the control subjects. The level of anti-Mycoplasma pneumoniae IgM was independent to both sex and age variables in patients group (p = 0.77). The level of anti-Mycoplasma pneumoniae IgG did not depend on subjects’ gender in control group, but was significantly higher in men compared with women in patients group.
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.

Hepatitis C virus (HCV) is a major public health problem worldwide. Replication and persistence of HCV genome have been described in the liver tissue as well as B cells lymphocyte. Several investigations have reported that long-term persistence of HCV in B cells may result in Hodgkin and Non-Hodgkin lymphoma. This study was aimed to determine frequency of HCV RNA in histological tissues obtained from patients suffered from Hodgkin and Non-Hodgkin lymphoma.
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-PCR products were sequenced and aligned to construct HCV phylogenic tree to evaluate the homology of sequences in comparison to the reference sequences retrieved from Genbank.
Overall, 6 Non-Hodgkin (20.6%) and 3 Hodgkin lymphoma (13.04%) samples showed positive PCR results for both 5’ UTR and HCV core RNA via nested PCR (P Despite low prevalence of HCV infection in Iran, high frequency of HCV RNA genotypes 3a (17.3%) has been found in patients with Hodgkin and Non-Hodgkin lymphoma. To improve treatment regimens, screening of HCV RNA in patients suffered from Hodgkin or Non-Hodgkin lymphoma is recommended which can be done through highly sensitive molecular means before and after immunosuppression status.

A single reactive IgG anti-Dengue virus ELISA test in the absence of IgM antibodies or NS1 antigen may denote current infection or past exposure to the virus. To determine whether IgG index value can be used to identify true current dengue infection we conducted a prospective observational study.
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 reactive results (n =57) in their first test were followed up and repeated sampling was asked for IgG index values were calculated according to the manufacturer’s instruction and classified as: low (2.2-2.5), medium (2.5-4.0) and high (>4.0).
16 out of 57 patients (28.1%) had low IgG Index value whereas 26 cases (45.6%) were categorized as medium and 15(26.3%) were classified as patients with high IgG index. Nine patients with paired reactive serology or antigen positive status were categorised as serologically confirmed dengue fever, 11 patients as not dengue with categorical evidence of other infections while the rest 37 casas with clinical, radiological and laboratory parameters suggestive of dengue but no serological confirmation as possible dengue. Among confirmed, possible and non-Dengue cases, 33.3, 32.4 and 0.0% had high Index value in comparison with 22.2, 29.7 and 27.3% showing low Index values, respectively.
Our results suggested a high IgG response in favour of true dengue infection than past exposure while no conclusions should drawn from a low or medium reactive GAC-ELISA results in the absence of IgM antibodies and NS1 Ag.

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 infections is 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.
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.
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 SAP1-3 expression with a particular effect against FLU-resistant isolates.
Carvacrol contains an essential oil (carvacrol); therefore, it can be considered as an alternative effective antifungal compound.

Vulvovaginal candidiasis is a common fungal infection among women during reproductive ages. Although, Candida albicans is accounted as the main etiologic agent of vaginitis, non-albicans species have arisen during last years. Resistant to antifungal drugs especially, fluconazole has been more reported by researchers from around the World. The aims of this study were to determine the prevalence of vulvovaginal candidiasis among suspected patients with vaginitis, the frequency of Candida species, and the susceptibility profiles of isolates to caspofungin, fluconazole and clotrimazole.
One hundred and twenty suspected women with vaginitis were examined by specialist physician and sampled using moisture swabs. Swabs were inoculated on CHROMagar Candida plates, incubated at 35ºC and detected all isolated Candida species using morphological, microcopy and molecular methods. The antifungal susceptibility tests with caspofungin, fluconazole and clotrimazole were applied using microdilution and Resazurin dye methods against all isolated yeasts.
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 the concentration of 2 μg/ml after 24h incubation that increased to 2 isolates after 48h incubation. All isolates were sensitive to fluconazole at the MIC ranges of 1-0.25 μg/ml, while 88.2% of them were inhibited at 0.25 μg/mL of clotrimazole. Candida albicans remains the most common agent of fungal vaginitis.
Although all of Candida isolates were susceptible to fluconazole in vitro, it should be used with caution for empirical therapy 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.