The "Iranian Journal of Microbiology (IJM) "is the offi­cial scientific quarterly publication of the Iranian Society of Microbiology which is published by Tehran University of Medical Sciences.  The areas that are covered by IJM are medical, veterinary, food and water, applied and  environmental microbiology. It ac­cepts Original Papers, Review Articles, Short Communications and Let­ters to the Editor in the fields of Microbiology.

Current Issue

Vol 13 No 3 (2021)
Published: 2021-06-05

Review Article(s)

  • XML | PDF | downloads: 34 | views: 15 | pages: 257-265

    Classical (CKp) and hypervirulent (hvKp) Klebsiella pneumoniae are two different circulating pathotypes. The aim of this study was to assess the prevalence, epidemiology and molecular relatedness of hvKps using a systemic review and meta-analysis. The data extracted from Medline, Embase, and Web of Science and finally 14 studies met the eligible criteria. To combine prevalence proportions of all studies, we performed the metaprop command embedded in the Meta package software. Totally, of 1814 K. pneumoniae isolates, 21.7% (394/1814) were hvKp. The molecular typing showed that all hvKp isolates were grouped into 50 different sequence types (STs) of them ST23, ST11, ST65 and ST86 were common. K1, K2 and K64 were dominant capsule serotypes that strongly related to ST23, ST65 and ST11, respectively. It seems that clonal group 23 (CG23) is associated with liver abscess and CG11 related to various clinical sources.

Original Article(s)

  • XML | PDF | downloads: 17 | views: 22 | pages: 266-273

    Background and Objectives: Neonatal sepsis is the third leading cause of neonatal death in the world. The patterns of pathogens causing neonatal sepsis varies in many countries. This study was aimed to identify hematological and microbiological profile of culture-proven neonatal sepsis in Indonesian tertiary neonatal intensive care unit (NICU).
    Materials and Methods: Hospital based cross-sectional study was conducted in all inborn neonates that were suspected sepsis neonatal over a period of six months from April to September 2019. Complete blood count, c-reactive protein (CRP) and blood culture were examined before antibiotic administration. Statistical analysis were calculated based on Chi-Square’s Test and Mann-Whitney U test and p <0.05 considered significant.
    Results: One hundred four inborn neonates admitted to NICU and diagnosed with suspected neonatal sepsis were recruited. Culture-proven neonatal sepsis were confirmed in 52 (50%) neonates, 13 (25%) in early-onset neonatal sepsis (EONS) and 39 (75%) in late-onset neonatal sepsis (LONS). The most common abnormal hematological profile were anemia and thrombocytopenia, with amount of 61.5% and 75%, respectively. High CRP only detected in 36.4% and only 18.5% experienced leukopenia. Gram negative bacteria responsible in 75% from total isolated pathogens. Klebsiella pneumoniae accounted for 48.1% followed by coagulase negative staphylococci (CONS) for 17.3% and Enterobacter cloacae for 11.5%.
    Conclusion: Anemia and thrombocytopenia were the top two hematological profile of culture-proven neonatal sepsis. Most causes of culture-proven neonatal sepsis were Gram negative bacteria and the dominant pathogen was K. pneumoniae.

  • XML | PDF | downloads: 25 | views: 27 | pages: 274-281

    Background and Objectives: Anaerobic infections are usually caused by the host’s endogenous flora due to a breach in the anatomical barriers and Bacteroides spp. are the most notorious organisms associated with anaerobic infections. The identification of anaerobes has been a challenge since times. MALDI-TOF-MS is a boon for aiding the rapid detection of anaerobic organisms and has helped us to enlist the distribution of various anaerobic pathogens.
    Materials and Methods: This retrospective analysis (January 2018 to December 2019) was carried out in a tertiary care hospital in North India, in which the anaerobic microbiological profile of all patients admitted to surgical wards, ICU, and OPD of various departments (Orthopedics, Surgery, Gynecology, and Obstetrics) was reviewed. Samples received were immediately processed aerobically (5% sheep blood agar and Mac Conkeyagar) as well as anaerobically (RCM and freshly prepared sheep blood agar) as per the laboratory protocols.
    Results: Bacteroides fragilis (19.12%) was the most common anaerobe whereas among aerobes Escherichia coli (30.2%) followed by Klebsiella pneumoniae (10.34%) were most commonly isolated. The majority of patients were males (56%) and the most common presentation was with abscesses (21.4%). Polymicrobial infections (69.51%) outnumbered monomicrobial ones (30.48%).
    Conclusion: There is a paucity of literature on anaerobe isolation from surgical infections from our country which motivated us to study anaerobic infections and the high sample size in our institute enabled us to study surgical infections from an anaerobic perspective. This will add to the knowledge of microbiologists and clinicians. MALDI-TOF MS helped in rapid and accurate identification and hence we could report a wider spectrum of organisms in our study.

  • XML | PDF | downloads: 38 | views: 38 | pages: 282-293

    Background and Objectives: Carbapenem treatment for Acinetobacter baumannii‎‎ infections presently faces threats owing to the production of several types of carbapenemase enzymes, prevalence of which varies among different countries. We explored the current trend of antibiotic resistance in A. baumannii clinical isolates from North West Iran, sought the mechanism of carbapenem resistance and addressed the sequence type groups in carbapenem resistant A. baumannii‎‎ (CRAB).
    Materials and Methods: A. baumannii‎‎ (n=112) isolates were recovered from various clinical specimens of patients admitted in internal, surgery, burn, infectious diseases and various ICUs wards. Genetically confirmed A. baumannii isolates were screened for carbapenem resistance by the Kirby-Bauer and E-test and the presence of blaMBL, blaOXA-like, ISAba1 genes by PCR. Sequence groups were identified by multiplex PCR.
    Results: Multidrug-resistance (MDR) was a characteristic feature of all A. baumannii isolates. Frequency of oxacillinase genes in combination including blaOXA-51-like/blaOXA-23-like, blaOXA-51-like/blaOXA-24/40-like and blaOXA-51-like/blaOXA-23-like/blaOXA-24/40-like was 82.1%, 36.6% and 25.8% respectively. Blending of oxacillinase and MBL genes was evident in eight blaOXA-23-like positive and 7 blaOXA-24-like positive isolates thereby depicting synchronous etiology of carbapenem resistance. Amongst CRAB isolates, 97.3% contained ISAba1 element and 50.9% belonged to the European clone II.
    Conclusion: Synchronicity among blaOXA-like with blaMBL and ISAba1 gene was a hallmark of this investigation. Though origin or route of transmission was not elucidated in this study but co-existence among OXA and MBL producing genes is a therapeutic concern demanding strict surveillance strategies and control programs to halt the dissemination of these isolates in the hospital setting.

  • XML | PDF | downloads: 17 | views: 21 | pages: 294-302

    Background and Objectives: Escherichia coli (E. coli) sequence type 131 (ST131) is associated with extended-spectrum beta-lactamase (ESBL) production and fluoroquinolone resistance. This study aimed to investigate the prevalence of ST131, ESBL, and plasmid-mediated quinolone resistance (PMQR) genes in the ciprofloxacin-resistant (CIPR) and ESBL producers from women with UTI.
    Materials and Methods: The CIP-resistant ESBL producing (CIPR/ESBL+) E. coli isolates were screened for ST131-by specific PCR of mdh and gyrB. The ESBL and PMQR genes were screened by single PCR. The ST131 and non-ST131 isolates were selected to determine the mutations of gyrA and parC using PCR and sequencing, and also their genetic background by the Pasteur-MLST scheme.
    Results: Overall, 55% (33/60) CIPR/ESBL+ isolates were identified as ST131 (94% O25b-ST131). Resistance rate to ampicillin-sulbactam (70%), aztreonam (97%) and gentamicin (61%), the prevalence of aac(6′)-Ib-cr (66%), blaCTX-M-15 (82%), the profile of qnrS+aac(6′)-Ib-cr (30%), and the double mutation in the parC was significantly higher in ST131 than non-ST131 isolates. The coexistence of PMQR and ESBL genes was found in more than 50% of ST131 and non-ST131 isolates. ST131 isolates differentiated into PST43 and PST506.
    Conclusion: Management of women with UTI caused by the CIPR/ESBL+ isolates (ST131) co-harbored PMQR, ESBL, and chromosomal mutations, is important for their effective therapy.

  • XML | PDF | downloads: 24 | views: 249 | pages: 303-311

    Background and Objectives: Carbapenems have been the choice of antibiotics for the treatment of infections caused by multidrug-resistant bacteria. The main objective of this study was to determine the prevalence of carbapenemase (blaVIM and blaIMP) producing isolates among Enterobacteriaceae, Pseudomonas aeruginosa, and Acinetobacter baumannii.
    Materials and Methods: A total of 1,151 clinical samples were collected from the patients visiting Annapurna Neurological Institute and Allied Science and Annapurna Research Centre, Kathmandu, between June 2017 and January 2018. Antibiotic susceptibility testing (AST) was performed on the Enterobacteriaceae, P. aeruginosa and A. baumannii isolates using the Kirby-Bauer disk diffusion method. The modified Hodge test (MHT) was performed on the carbapenem-resistant isolates to confirm carbapenemase production. DNA was extracted and then screened for blaVIM and blaIMP genes by multiplex PCR.
    Results: Of the total 1,151 clinical samples, 253 (22.0%) showed positive growth. Of them, 226 (89.3%) were identified as Enterobacteriaceae, P. aeruginosa, and A. baumannii. Among the 226 isolates, 106 (46.9%) were multidrug-resistant. Out of the 106, 97 (91.5%) isolates showed resistance to at least one of the carbapenem used. Among the 97 carbapenem-resistant isolates, 67 (69.1%) showed the modified Hodge test (MHT) positive results. blaVIM and blaIMP were detected in 40 and 38 isolates respectively using multiplex PCR assay.
    Conclusion: This study determined a high prevalence of MDR and carbapenem resistance among Enterobacteriaceae, P. aeruginosa, and A. baumannii as detected by the presence of blaVIM and blaIMP genes. This study recommends the use of rapid and advanced diagnostic tools along with conventional phenotypic detection methods in the clinical settings for early detection and management of drug-resistant pathogens to improve treatment strategies.

  • XML | PDF | downloads: 11 | views: 18 | pages: 312-318

    Background and Objectives: Human parechoviruses (HPeV) and Human enteroviruses (EV) frequently cause a sepsis-like illness in young infants (younger than three months). Therefore, this study was conducted to determine the frequency of HPeV and EV among the young infants with clinical signs and symptoms of sepsis in Ahvaz city, Iran.
    Materials and Methods: The blood specimens were collected from 100 (younger than 90 days hospitalized infants) including 54 (56.25%) males and 46 (43.75%) females with clinical signs and symptoms of sepsis-like disease. The RNA was extracted and tested for detection of VP1 region of HPeV and 5 UTR (Untranslated Region) of EV by RT-PCR. The sequences of positive of HPeV were further analyzed to determine HPeV genotyping.
    Results: 5/100 (5%) of patients including 2/46 (2%) females and 3/54 (3%) males tested positive for HPeV (P=0.85). The analysis of 5 positive VP1 region of HPeV revealed the genotype 1. The analysis of sequencing and phylogenetic tree revealed that the isolated HPeVs were genotype 1. While 38/100 (38%) specimens including 16 (16%) females and 22 (22%) males were tested positive for EV (P=0.68).
    Conclusion: The frequency of HPeV genotype 1 was 5% among the young infants with sepsis. While frequency of EV was 38% among the young infants with sepsis. This study showed HPeV genotype 1 and EV are dominant in this region.

  • XML | PDF | downloads: 16 | views: 13 | pages: 319-324

    Background and Objectives: Brucella is an intracellular pathogen that causes brucellosis in humans and animals. This study aimed to assess the results of brucellosis seroprevalence among participants of the Famenin brucellosis cohort with molecular investigation technique and determine Brucella-approved species.
    Materials and Methods: Following the first phase of the Famenin brucellosis cohort in 2016 which investigated the seroprevalence of brucellosis among 2367 participants in Famenin city, a total of 575 people including all seropositive and some seronegative people were examined again by wright serological tests in 2019. The PCR assay was accomplished on all cases that have wright titers ≥ 1/20 for tracing Brucella DNA using BCSP31 target gene and IS711 locus.
    Results: Out of 575 studied cases, 145 people had wright titers ≥ 1/20. The PCR reactions of these 145 blood samples were positive in 63/145 (43.44%) tested samples using primers (B4/B5) for Brucella genus detection. In the second PCR assay using specific-primers for Brucella abortus and Brucella melitensis, 18/63 (28.57%) of the samples were diagnosed as B. abortus, and 18/63 (28.57%) were diagnosed as B. melitensis.
    Conclusion: In this study, using the selected specific genes for the diagnosis of Brucella in the genus and species levels, the PCR technique was evaluated as a promising method for the rapid and safe detection of brucellosis besides the serological test for more accurate detection of brucellosis especially in cases that are not definitive.

  • XML | PDF | downloads: 12 | views: 15 | pages: 325-336

    Background and Objectives: Brucellosis and Q fever are considered as occupational hazards to people in contact with domestic animals or their carcasses. The present cross-sectional study was carried out to determine the seroprevalence of brucellosis and Q fever among professions at risk in the North Khorasan Province, northeastern Iran during 2020.
    Materials and Methods: In this study, 185 sera samples were collected from butchers, slaughterhouse workers, farmers, and veterinarians in different counties of the province. The collected sera were tested by ELISA test for the detection of IgG antibodies against Coxiella burnetii and Brucella spp. A questionnaire was filled for each participant to investigate demographic characteristics information (i.e., age, gender, educational status, occupation, years of occupational experience, and location), and any exposure to risk factors (animals Keeping, consumption of unpasteurized dairy products, exposure to ill or dead animals, tick bite, splashing animal fluids, travel history, and use of personal protective equipment) that could be associated with these infections.
    Results: The seroprevalence of antibodies against C. burnetii and Brucella spp. were 17.2% and 19.4%, respectively. Twelve participants also had Q fever and brucellosis co-infection, with a prevalence of 6.4%.
    Conclusion: Based on the results, it is concluded that brucellosis and Q fever occur among the high-risk populations in this area and it needs more surveillance to control the diseases by public health and veterinary authorities.

  • XML | PDF | downloads: 11 | views: 19 | pages: 337-344

    Background and Objectives: Avian respiratory disease complex (RDC) is one of the most detrimental economic diseases that affected different parts of the world. Various pathogens cause the disease, but the most significant viral pathogens include avian influenza virus (AIV), infectious bronchitis virus (IBV), and Newcastle disease virus (NDV) are the most prevalent. To detect these pathogens, various methods have been discovered in the last decades. Detection and characterization of viruses by metagenomics methods have improved our knowledge about the role of virome in the avian complex respiratory disease.
    Materials and Methods: This research investigates the viral pathogen populations that mostly participate in emerging these diseases using the NGS method RNA-sequencing. In surveillance of ten broiler farms from different cities with respiratory symptoms, trachea samples were collected to determine the pathogenic virome causing the disease.
    Results: In this metagenomics analysis, nine viral families were identified, comprising 72.82% of RNA viruses, 24.32% of RT viruses, and 2.86% of DNA viruses. RNA viruses had the highest contribution to the respiratory disease complex instead of disease, including paramyxoviridae, orthomyxoviridae, coronaviridae, and picornaviridae viruses. Other viruses from the RNA viruses and DNA virus families were also identified in addition to these results.
    Conclusion: This research suggests that studies of pathogenic viromes in different diseases can help monitor different diseases and predict their future occurrence.

  • XML | PDF | downloads: 17 | views: 27 | pages: 345-351

    Background and Objectives: The frequency of multiple resistant bacterial infections, including carbapenems, is increasing worldwide. As the decrease in treatment options causes difficulties in treatment, interest in new antimicrobials is increasing. One of the promising natural ingredients is curcumin. It is known to be effective in bacteria such as Pseudomonas aeruginosa, Escherichia coli, Burkholderia pseudomallei through efflux pump inhibition, toxin inhibition and enzymes. However, because its bioavailability is poor, it seffectiveness occurs in combination with antibiotics. In the study, the interaction of meropenem and curcumin in carbapenemase producing strains of Klebsiella pneumoniae was tested.
    Materials and Methods: Thirty-nine Klebsiella pneumoniae isolates, resistant to meropenem, were used in this study. From those 15 MBL, 6 KPC, 17 OXA-48 and 1 AmpC resistance pattern were detected by combination disk method. Meropenem and Curcumin MIC values were determined by liquid microdilution. Checkerboard liquid microdilution was used to determine the synergy between meropenem and curcumin.
    Results: Synergistic effects were observed in 4 isolates producing MBL, 3 isolates producing KPC, 4 isolates producing OXA-48, and 1 isolates producing AmpC (totally 12 isolates) according to the calculated FICI. No antagonistic effects were observed in any isolates.
    Conclusion: Curcumin was thought to be an alternative antimicrobial in combination therapies that would positively contribute to the treatment of bacterial infection. The effectiveness of this combination should be confirmed by other in vitro and clinical studies.

  • XML | PDF | downloads: 13 | views: 15 | pages: 352-359

    Background and Objectives: Candidiasis and pityriasis versicolor are opportunistic fungal infections that are caused by Candida spp. and Malassezia spp. yeasts. Conventional drugs like azole and amino derivatives are known to treat fungal skin diseases. However, drawbacks like long-term side effects and drug resistance lead to investigate on antifungal properties of phytochemicals as an alternative to available synthetic drugs.
    Materials and Methods: The herbal nano hydrogel was successfully synthesized from Quince Seed extract followed by ultrasonic treatment and it has been formulated using a mixture of essential oils. We evaluated the antifungal in vitro assay for a mixture of essential oils in combination with herbal nano hydrogel against Candida albicans and Malasezia furfur strains by micro dilution method.
    Results: The results indicated that essential oils possess antifungal activity with the MIC value of 12.5 and 6.24 mg/ml against C. albicans and M. furfur, respectively. No fungicidal effect was reported for the herbal hydrogel before nanofabrication while it shown some antifungal activity after ultrasonic treatment for 5 and 10 minutes. As anticipated; the antifungal property of essential oil mixture was appreciably improved when it combined with herbal nano hydrogel where the highest level of inhibition was observed at concentration of 3.125 mg/ml for both strains. The loss in biological activity observed when the ultrasonic treatment on herbal nano hydrogel performed for longer time.
    Conclusion: The proposed plant-based nano formulation shown promising in vitro antifungal activities against C. albicans and M. furfur strains and its antifungal properties were comparable with commercially available agents like clotrimazole. The new formulation expected to be safe with minimum long-term side effects. Further investigations are underway to confirm the safety and the mechanism of the action of this new herbal formulation.

  • XML | PDF | downloads: 8 | views: 22 | pages: 360-371

    Background and Objectives: Helicobacter pylori causes several gastrointestinal diseases, including asymptomatic gastritis, chronic peptic ulcer, duodenal ulcer, lymphoma of the mucosa-associated lymphoid tissue (MALT), and gastric adenocarcinoma. In recent years, failure to eradicate H. pylori infections has become an alarming problem for physicians. It is now clear that the current treatment strategies may become ineffective, necessitating the development of innovative antimicrobial compounds as alternative treatments.
    Materials and Methods: In this experimental study, a cell-penetrating peptide-conjugated peptide nucleic acid (CPP-PNA) was used to target the cagA expression. cagA expression was evaluated using RT-qPCR assay after treatment by the CPP-PNA in cell culture and animal model. Additionally, immunogenicity and toxicity of the CPP-PNA were assessed in both cell culture and animal models.
    Results: Our analysis showed that cagA mRNA levels reduced in H. pylori-infected HT29 cells after treatment with CPP-PNA in a dose-dependent manner. Also, cagA expression in bacterial RNA extracted from stomach tissue of mice treated with PNA was reduced compared to that of untreated mice. The expression of inflammatory cytokines also decreased in cells and tissue of H. pylori-infected mice after PNA treatment. The tested CPP-PNA showed no significant adverse effects on cell proliferation of cultured cells and no detectable toxicity and immunogenicity were observed in mice.
    Conclusion: These results suggest the effectiveness of CPP-PNA in targeting CagA for various research and therapeutic purposes, offering a potential antisense therapy against H. pylori infections.

  • XML | PDF | downloads: 13 | views: 16 | pages: 372-380

    Background and Objectives: Cancer incidence and recurrence, antibiotic resistance, and overuse of antibiotics have become a global concern. The purpose of this study was to identify and isolate bacteria from the skin of the Rana ridibunda, Iranian swamp frog, which has produced antimicrobial compounds, and investigate its cytotoxic activity on the breast (MCF7) and glioblastoma (U87) cancer cell line.
    Materials and Methods: An antibiotic-producing bacterium was isolated from the frog skin. The bacterium was identified based on 16S rDNA sequencing and biochemical and morphological characteristics. Antimicrobial activity of the culture supernatant was examined by disc diffusion and MIC methods. Cytoplasmic and cell wall extracts of bacteria were prepared by sonication. SDS-PAGE was then used to examine protein contents of them. The cancer cell lines were treated with cytoplasmic and cell wall extracts at different concentrations. The effects of cytotoxicity were assessed by MTT assay at 24 and 48 h intervals. Finally, the results were analyzed by SPSS.
    Results: The isolated bacterium was identified as a new strain of Bacillus atrophaeus. MIC and disc diffusion methods showed that the Bacillus atrophaeus antimicrobial activity was broad spectrum. MTT assay showed IC50 values 30 μg/ml and 20 μg/ml for U87 and MCF7 cells after 24-48 h exposure, respectively.
    Conclusion: The cytoplasmic extracts of Bacillus atrophaeus has anticancer potential and can be used as an alternative or complementary candidate in the treatment of cancer. Further in vivo and in vitro mechanistic studies are suggested to confirm the biological activities.

  • XML | PDF | downloads: 11 | views: 40 | pages: 381-388

    Background and Objectives: In 2020 the whole world is experiencing a pandemic condition due to infection with the SARS-CoV-2 virus which can cause the COVID-19 disease. This condition results in “Panic Buying”, because everyone tries to avoid the spread and transmission of the COVID-19 disease by doing various ways, one of which is by taking additional supplements such as vitamin C and probiotic supplements.
    Materials and Methods: The materials used were mice Mus musculus male DDY strain aged 1-2 months. Probiotic supplement Lactobacillus acidophilus La-14 with a viability of 1 × 108 CFU/ml. with a weight of 0.16 grams dissolved in 0.25 ml 0.9% NaCl. Vitamin C used is a commercial vitamin C tablet, weighing 0.06 grams in 0.25 ml 0.9% NaCl. Meanwhile, the feed for mice (Mus musculus) is a complete feed from Pokphand with the code BR1 CP511B. Lung histology preparations data were analysed descriptively and statistically through the test Chi square while the data on the number of lymphocytes were analysed descriptively.
    Results: The histological observations of lungs of Mus musculus showed that in the treatment of ML, MV, and MKA test was carried out chi square ratio between the groups that did not have lymphocyte infiltration and those that had lymphocyte infiltration showed a significant difference (p <0.05). Meanwhile, the results of the lymphocyte count showed that ML and MV treatment was higher than that of MK treatment.
    Conclusion: It is suggested that the administration of probiotics can stimulate and modulate the respiratory immune system.

  • XML | PDF | downloads: 8 | views: 11 | pages: 389-398

    Background and Objectives: Gamma-aminobutyric acid (GABA) is a non-protein amino acid produced by lactic acid bacteria. Among GABA-producing bacteria, lactic acid bacteria have received more attention due to their probiotic nature and properties such as inhibiting pathogenic bacteria, strengthening the immune system, and so on.
    Materials and Methods: Investigation on the effect of three independent variables including pH (4.7, 4.9 and 5.1), glutamic acid (1, 2 and 3 mgg-1) and salt (2, 2.5 and 3%) on GABA production in low fat cheese by probiotic bacteria.
    Results: By increasing the amount of glutamic acid and decreasing the pH from 5.1 to 4.7, the amount of GABA production in ultra-filtration cheese significantly increased on the 15th and 30th days of production (p≤0.05), while by increasing the amount of salt the production GABA decreased on the 15th and 30th days. Simultaneous optimal conditions to achieve maximum GABA production in cheese on the 15th and 30th production day was respectively 167.7917 mg/kg-1 and 220.125 mg/kg-1 using 3 mg/g glutamic acid, 2% salt at pH 4.7.
    Conclusion: The results showed that by identifying probiotic bacteria with the highest potential for GABA production and optimizing the culture medium, more GABA can be produced in food products and a positive step can be taken to produce pragmatic products and promote consumer health.

  • XML | PDF | downloads: 12 | views: 19 | pages: 399-406

    Background and Objectives: Halothermophilic bacteria are adapted to high osmolarity and can grow in high saline environments and high temperatures. This study was aimed at the isolation of halothermophilic bacteria from Howz-e Sultan hypersaline lake in the central desert zone in Iran.
    Materials and Methods: Samples were collected and after preparing dilutions, the samples were cultured on Molten haloid agar with different salt concentrations (5-35%), then the plates were incubated at 35-70ºC in both aerobic and anaerobic conditions. Biochemical characterizations, utilization of carbon sources, production of exoenzymes and antibiotic susceptibility were investigated. Taxonomic and phylogenetic analyses were performed using 16S rRNA gene sequences.
    Results: One of the isolated bacteria was found to be Gram-positive, hyperhalophilic, thermophilic, endospore-forming, and was named as 1-9 h isolate. The bacterial cells were bacilli-shaped, which produced endospores at a subterminal position. This isolate was an aerobe and facultative anaerobe and grew between pH 5.0 and 10.0 (optimal growth at pH 7.0-7.5), at temperature between 15°C and 65°C (optimal growth at 40-45°C) and at salinity of 9-32% (w/v) NaCl, growing optimally at 18% (w/v) NaCl. On the basis of 16S rRNA gene sequence analysis, isolate 1-9 h belongs to the genus Bacillus within the phylum Firmicutes and showed the closest phylogenetic similarity to Gracilibacillus sp. IBP-V003 (99.0%).
    Conclusion: Based on the results of its phenotypic and genotypic properties, strain 1-9 h represents a novel strain of the genus Gracilibacillus. It can be used in various fields of industry and biotechnology.

  • XML | PDF | downloads: 18 | views: 13 | pages: 407-417

    Background and Objectives: The use of endophytic fungi for management of phenol residue in paper and pulp industries has been shown as cost-effective and eco-friendly approach. In this study, isolation of endophytic fungi from roots, stems, and leaves of Hibiscus sabdariffa was conducted. Additionally, the isolated fungi were examined for their ability to degrade phenol and its derivatives in paper and pulp industrial samples, using different growth conditions.
    Materials and Methods: Out of 35 isolated endophyitc fungi, 31 were examined for their phenol biodegradation capacity using Czapek Dox broth medium containing Catechol and Resorcinol as a sole carbon source at final concentrations of 0.4, 0.6 and 0.8%.
    Results: A total of 35 fungal species belonging to 18 fungal genera were isolated and identified from different parts of H. sabdariffa plants. All strains have the capability for degrading phenol and their derivatives with variable extents. The optimum condition of degrading phenol in paper and pulp effluent samples by Fusarium poae11r7 were at pH 3-5, temperature at 28-35°C, good agitation speed at no agitation and 100 rpm.
    Conclusion: All endophytic fungal species can utilize phenol and its derivatives as a carbon source and be the potential to degrade phenol in industrial contaminants.

  • XML | PDF | downloads: 14 | views: 14 | pages: 418-424


    Background and Objectives: Yeasts are an important portion of microbial communities of soil due to their bioactivity  for ecosystem safety. Soil yeast abundance and diversity are likely to be affected under harsh environmental and climatic conditions. In Iraq, human activity and climatic changes especially high temperature which may alter microbial communities in soil. Very little is known about yeast abundance and diversity in a hot climatic region.

    Materials and Methods: By PCR technique, soil yeast abundance and diversity were investigated under extreme environmental and climatic conditions , as well as the effects of soil properties and vegetation cover in semi-arid lands.

    Results: In all, 126 yeast strains were isolated and identified as belonging to 13 genera and 26 known species. The maximum quantity of yeast was 0.8 X 102 CFU g-1 of soil, with significantly varied in abundance and diversity depending on soil properties and presence of vegetation.

    Conclusion: The results show that soil yeast abundance in these regions was significantly decreased. However, semi-arid lands are still rich in yeast diversity, and many species have adapted to survive in such conditions.

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