International Journal of Microbiology The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Urinary Tract Infection among Antiretroviral Therapy Users and Nonusers in Jimma University Specialized Hospital, Jimma, Ethiopia Wed, 16 Apr 2014 13:57:41 +0000 Background. The introduction of antiretroviral therapy (ART) has dramatically reduced morbidity related with bacterial infection including urinary tract infection (UTI) among patients with HIV/AIDS. This study was carried out to determine the prevalence of UTI and identify common bacterial etiologies among HIV/AIDS patients of ART users and nonusers in Jimma University Specialized Hospital. Methods. A comparative cross sectional study was conducted from September to December 2012 on 367 ART users and 114 nonuser patients attending ART clinic. Sociodemographic characteristics, associated factors, and urine samples were collected; culture, biochemical tests, Gram stain, and drug sensitivity tests were done. Results. Of 467 examined urine samples, 56 (12%) had significant bacterial growth. Forty-six (12.5%) of the cases were ART users and 10 (10%) were nonusers. E. coli was the predominant isolate in both ART users (25 (54.3%)) and nonusers (6 (6%)). Majority of the bacterial isolates were from females. Most (>75%) of the isolates from both groups were resistant to ampicillin and trimethoprim-sulfamethoxazole but sensitive to norfloxacine, ceftriaxone, and chloramphenicol. Conclusion. There was no statistically significant difference regarding the prevalence of significant bacterial growth between ART users and nonusers. Therefore, it is recommended that UTI in both groups should be managed with drugs that show sensitivity. Serkadis Debalke, Waqtola Cheneke, Haimanot Tassew, and Mohammed Awol Copyright © 2014 Serkadis Debalke et al. All rights reserved. Transcriptional Response of Selenopolypeptide Genes and Selenocysteine Biosynthesis Machinery Genes in Escherichia coli during Selenite Reduction Tue, 15 Apr 2014 16:25:16 +0000 Bacteria can reduce toxic selenite into less toxic, elemental selenium (Se0), but the mechanism on how bacterial cells reduce selenite at molecular level is still not clear. We used Escherichia coli strain K12, a common bacterial strain, as a model to study its growth response to sodium selenite (Na2SeO3) treatment and then used quantitative real-time PCR (qRT-PCR) to quantify transcript levels of three E. coli selenopolypeptide genes and a set of machinery genes for selenocysteine (SeCys) biosynthesis and incorporation into polypeptides, whose involvements in the selenite reduction are largely unknown. We determined that 5 mM Na2SeO3 treatment inhibited growth by ∼50% while 0.001 to 0.01 mM treatments stimulated cell growth by ∼30%. Under 50% inhibitory or 30% stimulatory Na2SeO3 concentration, selenopolypeptide genes (fdnG, fdoG, and fdhF) whose products require SeCys but not SeCys biosynthesis machinery genes were found to be induced ≥2-fold. In addition, one sulfur (S) metabolic gene iscS and two previously reported selenite-responsive genes sodA and gutS were also induced ≥2-fold under 50% inhibitory concentration. Our findings provide insight about the detoxification of selenite in E. coli via induction of these genes involved in the selenite reduction process. Antonia Y. Tetteh, Katherine H. Sun, Chiu-Yueh Hung, Farooqahmed S. Kittur, Gordon C. Ibeanu, Daniel Williams, and Jiahua Xie Copyright © 2014 Antonia Y. Tetteh et al. All rights reserved. Genotyping of ESBL Producing Uropathogenic Escherichia coli in West of Iran Tue, 15 Apr 2014 08:22:59 +0000 Background and Objective. Urinary tract infection (UTI) is one of the most common bacterial infections in the world. Molecular fingerprinting of UTI isolates such as pulsed-Field Gel Electrophoresis using for Clonal distribution and determine of predominant type. The aim of the study was to determine genotyping of ESBL producing UPECs. Material and Methods. 200 UPEC isolates from outpatients with UTI were obtained. Antimicrobial susceptibility and interpretation were performed by disk diffusion. Virulence factors for UPECs were screened by using PCR. UPECs were analyzed by Pulsed-Field Gel Electrophoresis and images analyzed by Phoretix1DPro software. Results. A total of 200 isolates of UPECs, 24.5% () of isolates, were positive for ESBL production. Resistance ranged from 0% for amikacin and imipenem to over 93.9% for carbenicillin and ampicillin. Frequencies of haemagglutination, haemolysin, and hydrophobicity were 51%, 18.3%, and 14.28%, respectively. A total of 10 different genotypes were obtained, which include nine common clones and one single clone. Conclusion. We confirmed the prevalence of virulence phenotyping especially Haemagglutination among UPEC strains and that it can also contribute to virulence in these strains. Large diversity in genotypes was observed in the isolates that could be indicative of different sources of infection in community acquired. Parviz Mohajeri, Gita Darfarin, and Abbas Farahani Copyright © 2014 Parviz Mohajeri et al. All rights reserved. Removal of Total Coliforms, Thermotolerant Coliforms, and Helminth Eggs in Swine Production Wastewater Treated in Anaerobic and Aerobic Reactors Wed, 09 Apr 2014 08:34:18 +0000 The present work evaluated the performance of two treatment systems in reducing indicators of biological contamination in swine production wastewater. System I consisted of two upflow anaerobic sludge blanket (UASB) reactors, with 510 and 209 L in volume, being serially arranged. System II consisted of a UASB reactor, anaerobic filter, trickling filter, and decanter, being also organized in series, with volumes of 300, 190, 250, and 150 L, respectively. Hydraulic retention times (HRT) applied in the first UASB reactors were 40, 30, 20, and 11 h in systems I and II. The average removal efficiencies of total and thermotolerant coliforms in system I were 92.92% to 99.50% and 94.29% to 99.56%, respectively, and increased in system II to 99.45% to 99.91% and 99.52% to 99.93%, respectively. Average removal rates of helminth eggs in system I were 96.44% to 99.11%, reaching 100% as in system II. In reactor sludge, the counts of total and thermotolerant coliforms ranged between 105 and 109 MPN (100 mL)−1, while helminth eggs ranged from 0.86 to 9.27 eggs g−1 TS. Silvia Helena Zacarias Sylvestre, Estevam Guilherme Lux Hoppe, and Roberto Alves de Oliveira Copyright © 2014 Silvia Helena Zacarias Sylvestre et al. All rights reserved. Virulence Factors Contributing to Pathogenicity of Candida tropicalis and Its Antifungal Susceptibility Profile Wed, 02 Apr 2014 09:52:11 +0000 The incidence of invasive candidiasis has increased over the past few decades. Although Candida albicans remains by far the most common species encountered, in recent years shift towards non-albicans Candida species like Candida tropicalis is noted. Here in this study we determined the virulence factors and antifungal susceptibility profile of 125 C. tropicalis isolated from various clinical specimens. Biofilm formation was seen in 53 (42.4%) isolates. Coagulase production was noted in 18 (14.4%) isolates. Phospholipase enzyme was the major virulent factor produced by C. tropicalis isolates. A total of 39 biofilm forming isolates showed phospholipase activity. Proteinase activity was demonstrated by 65 (52%) isolates. A total of 38 (30.4%) isolates showed haemolytic activity. Maximum isolates demonstrated resistance to fluconazole. Fluconazole resistance was more common in C. tropicalis isolated from blood cultures. Antifungal resistance was more in isolates possessing the ability to produce phospholipase and biofilm. C. tropicalis exhibit a great degree of variation not only in their pathogenicity but also in their antifungal susceptibility profile. The identification of virulence attributes specific for each species and their correlation with each other will aid in the understanding of the pathogenesis of infection. Sachin C. Deorukhkar, Santosh Saini, and Stephen Mathew Copyright © 2014 Sachin C. Deorukhkar et al. All rights reserved. Lack of Outer Membrane Protein A Enhances the Release of Outer Membrane Vesicles and Survival of Vibrio cholerae and Suppresses Viability of Acanthamoeba castellanii Tue, 01 Apr 2014 09:13:57 +0000 Vibrio cholerae, the causative agent of the diarrhoeal disease cholera, survives in aquatic environments. The bacterium has developed a survival strategy to grow and survive inside Acanthamoeba castellanii. It has been shown that V. cholerae expresses outer membrane proteins as virulence factors playing a role in the adherence to interacted host cells. This study examined the role of outer membrane protein A (OmpA) and outer membrane vesicles (OMVs) in survival of V. cholerae alone and during its interaction with A. castellanii. The results showed that an OmpA mutant of V. cholerae survived longer than wild-type V. cholerae when cultivated alone. Cocultivation with A. castellanii enhanced the survival of both bacterial strains and OmpA protein exhibited no effect on attachment, engulfment, and survival inside the amoebae. However, cocultivation of the OmpA mutant of V. cholerae decreased the viability of A. castellanii and this bacterial strain released more OMVs than wild-type V. cholerae. Surprisingly, treatment of amoeba cells with OMVs isolated from the OmpA mutant significantly decreased viable counts of the amoeba cells. In conclusion, the results might highlight a regulating rule for OmpA in survival of V. cholerae and OMVs as a potent virulence factor for this bacterium towards eukaryotes in the environment. Soni Priya Valeru, Salah Shanan, Haifa Alossimi, Amir Saeed, Gunnar Sandström, and Hadi Abd Copyright © 2014 Soni Priya Valeru et al. All rights reserved. Antibiofilm Activity, Compound Characterization, and Acute Toxicity of Extract from a Novel Bacterial Species of Paenibacillus Mon, 24 Mar 2014 07:10:30 +0000 The effectiveness of many antimicrobial agents is currently decreasing; therefore, it is important to search for alternative therapeutics. Our study was carried out to assess the in vitro antibiofilm activity using microtiter plate assay, to characterize the bioactive compounds using Ultra Performance Liquid Chromatography-Diode Array Detection and Liquid Chromatography-Mass Spectrometry and to test the oral acute toxicity on Sprague Dawley rats of extract derived from a novel bacterial species of Paenibacillus strain 139SI. Our results indicate that the crude extract and its three identified compounds exhibit strong antibiofilm activity against a broad range of clinically important pathogens. Three potential compounds were identified including an amino acid antibiotic C8H20N3O4P (MW 253.237), phospholipase A2 inhibitor C21H36O5 (MW 368.512), and an antibacterial agent C14H11N3O2 (MW 253.260). The acute toxicity test indicates that the mortality rate among all rats was low and that the biochemical parameters, hematological profile, and histopathology examination of liver and kidneys showed no significant differences between experimental groups . Overall, our findings suggest that the extract and its purified compounds derived from novel Paenibacillus sp. are nontoxic exhibiting strong antibiofilm activity against Gram-positive and Gram-negative pathogens that can be useful towards new therapeutic management of biofilm-associated infections. Saad Musbah Alasil, Rahmat Omar, Salmah Ismail, and Mohd Yasim Yusof Copyright © 2014 Saad Musbah Alasil et al. All rights reserved. Detection of Integrase Gene in E. coli Isolated from Pigs at Different Stages of Production System Mon, 10 Mar 2014 12:12:49 +0000 Integrons are one of the genetic elements involved in the acquisition of antibiotic resistance. The aim of the present research is to investigate the presence of integrons in commensal Escherichia coli (E. coli) strains, isolated from pigs at different stages of production system and from the environment in an Argentinian farm. Five sows postpartum and five randomly chosen piglets from each litter were sampled by rectal swabs. They were sampled again at day 21 and at day 70. Environmental samples from the farm were also obtained. E. coli containing any integron class or combination of both integrons was detected by polymerase chain reaction in 100% of sows and in piglets at different stages of production: farrowing pen stage 68.1%;, weaning 60%, and growing/finishing 85.8%, showing an increase along the production system. From environmental samples 78.4% of E. coli containing any integron class was detected. We conclude that animals and farm environment can act as reservoirs for potential spread of resistant bacteria by means of mobile genetic elements as integrons, which has a major impact on production of food animals and that can reach man through the food chain, constituting a problem for public health. Eulalia de la Torre, Rocío Colello, Nora Lía Padola, Analía Etcheverría, Edgardo Rodríguez, Fabián Amanto, María Ofelia Tapia, and Alejandro Luis Soraci Copyright © 2014 Eulalia de la Torre et al. All rights reserved. Escherichia coli Strains Isolated from the Uteri Horn, Mouth, and Rectum of Bitches Suffering from Pyometra: Virulence Factors, Antimicrobial Susceptibilities, and Clonal Relationships among Strains Sun, 09 Mar 2014 12:02:23 +0000 Pyometra is recognized as one of the main causes of disease and death in the bitch, and Escherichia coli is the major pathogen associated with this disease. In this study, 70 E. coli isolates from the uteri horn, mouth, and rectum of bitches suffering from the disease and 43 E. coli isolates from the rectum of clinically healthy bitches were examined for the presence of uropathogenic virulence genes and susceptibility to antimicrobial drugs. DNA profiles of isolates from uteri horn and mouth in bitches with pyometra were compared by REP, ERIC, and BOX-PCR. Virulence gene frequencies detected in isolates from canine pyometra were as follows: 95.7% fim, 27.1% iss, 25.7% hly, 18.5% iuc, and 17.1% usp. Predominant resistance was determined for cephalothin, ampicillin, and nalidixic acid among the isolates from all sites examined. Multidrug resistance was found on ∼50% pyometra isolates. Using the genotypic methods some isolates from uteri, pus, and saliva of the same bitch proved to have identical DNA profiles which is a reason for concern due to the close relationship between household pets and humans. Juliana M. A. Agostinho, Andressa de Souza, Ruben P. Schocken-Iturrino, Lívia G. Beraldo, Clarissa A. Borges, Fernando A. Ávila, and José M. Marin Copyright © 2014 Juliana M. A. Agostinho et al. All rights reserved. Erratum to “Design and Optimization of a Process for Sugarcane Molasses Fermentation by Saccharomyces cerevisiae Using Response Surface Methodology” Tue, 25 Feb 2014 09:10:17 +0000 Nour Sh. El-Gendy, Hekmat R. Madian, and Salem S. Abu Amr Copyright © 2014 Nour Sh. El-Gendy et al. All rights reserved. Type IV Secretion System Is Not Involved in Infection Process in Citrus Sun, 23 Feb 2014 07:49:13 +0000 The type IV secretion system (T4SS) is used by Gram-negative bacteria to translocate protein and DNA substrates across the cell envelope and into target cells. Xanthomonas citri subsp. citri contains two copies of the T4SS, one in the chromosome and the other is plasmid-encoded. To understand the conditions that induce expression of the T4SS in Xcc, we analyzed, in vitro and in planta, the expression of 18 ORFs from the T4SS and 7 hypothetical flanking genes by RT-qPCR. As a positive control, we also evaluated the expression of 29 ORFs from the type III secretion system (T3SS), since these genes are known to be expressed during plant infection condition, but not necessarily in standard culture medium. From the 29 T3SS genes analyzed by qPCR, only hrpA was downregulated at 72 h after inoculation. All genes associated with the T4SS were downregulated on Citrus leaves 72 h after inoculation. Our results showed that unlike the T3SS, the T4SS is not induced during the infection process. Tiago Rinaldi Jacob, Marcelo Luiz de Laia, Leandro Marcio Moreira, Janaína Fernandes Gonçalves, Flavia Maria de Souza Carvalho, Maria Inês Tiraboschi Ferro, and Jesus Aparecido Ferro Copyright © 2014 Tiago Rinaldi Jacob et al. All rights reserved. Antibacterial Activities and In Vitro Anti-Inflammatory (Membrane Stability) Properties of Methanolic Extracts of Gardenia coronaria Leaves Wed, 19 Feb 2014 00:00:00 +0000 This work is carried out with Gardenia coronaria leaves that belong to the family Rubiaceae, which is a small-to-medium-sized but tall, deciduous tree, 7.6–9 m high on an average. Leaves are used for the treatment of rheumatic pain and bronchitis. The leaf of the plant consists of coronalolide, coronalolic acid, coronalolide methyl ester, ethyl coronalolate acetate triterpenes (secocycloartanes), and so forth. Methanol extract from the leaves of Gardenia coronaria was completely screened for membrane stability and antibacterial activity. The lower concentrations of Methanolic leaf extract of Gardenia coronaria gave good antimicrobial and anti-inflammatory activity, but higher concentrations gave relatively more projecting antibacterial activity in vitro as compared with Kanamycin. The crude drug’s anti-inflammatory effects were compared with those of Aspirin as positive control. The Methanolic extracts of Gardenia coronaria leaves possessed a broad spectrum antibacterial activity against a variety of both Gram-negative and Gram-positive organisms like Streptococcus agalactiae, Escherichia coli, Pseudomonas aeruginosa, Bacillus cereus, Shigella sonnei, Shigella boydii, and Proteus mirabilis, with a zone of inhibition from 10 to 16 mm. The extract also showed good membrane stability to be considered as having significant anti-inflammatory action. Amin Chowdhury, Shofiul Azam, Mohammed Abdullah Jainul, Kazi Omar Faruq, and Atiqul Islam Copyright © 2014 Amin Chowdhury et al. All rights reserved. False-Negative Rate of Gram-Stain Microscopy for Diagnosis of Septic Arthritis: Suggestions for Improvement Thu, 13 Feb 2014 08:17:14 +0000 We quantify the false-negative diagnostic rate of septic arthritis using Gram-stain microscopy of synovial fluid and compare this to values reported in the peer-reviewed literature. We propose a method of improving the diagnostic value of Gram-stain microscopy using Lithium Heparin containers that prevent synovial fluid coagulation. Retrospective study of the Manchester Royal Infirmary microbiology database of patients undergoing synovial fluid Gram-stain and culture between December 2003 and March 2012 was undertaken. The initial cohort of 1896 synovial fluid analyses for suspected septic arthritis was reduced to 143 after exclusion criteria were applied. Analysis of our Gram-stain microscopy yielded 111 false-negative results from a cohort size of 143 positive synovial fluid cultures, giving a false-negative rate of 78%. We report a false-negative rate of Gram-stain microscopy for septic arthritis of 78%. Clinicians should therefore avoid the investigation until a statistically significant data set confirms its efficacy. The investigation's value could be improved by using Lithium Heparin containers to collect homogenous synovial fluid samples. Ongoing research aims to establish how much this could reduce the false-negative rate. Paul Stirling, Radwane Faroug, Suheil Amanat, Abdulkhaled Ahmed, Malcolm Armstrong, Pankaj Sharma, and Ahmed Qamruddin Copyright © 2014 Paul Stirling et al. All rights reserved. Molecular Analysis of Human Metapneumovirus Detected in Patients with Lower Respiratory Tract Infection in Upper Egypt Thu, 30 Jan 2014 11:27:22 +0000 Introduction. Since 2001, when Human metapneumovirus (HMPV) was isolated in the Netherlands, the virus has been detected in several continents. Although reports have confirmed the prevalence of HMPV worldwide, data from Egypt remain limited. HMPV plays an important role in respiratory tract infections in individuals of all ages particularly in children. This study was aimed at estimating the prevalence of HMPV in patients with community-acquired lower respiratory infection in Upper Egypt and characterizing the circulating Egyptian HMPV strains for the first time. Materials and Methods. From 2005 to 2008, respiratory samples from 520 patients were analyzed for the presence of HMPV by real-time RT-PCR. Molecular and phylogenetic analyses were performed on partial fusion gene sequences of HMPV-positive patients. Results. HMPV-positive patients were detected in 2007-2008. The overall infection rate was 4%, while 57% of the patients were children. Sequence analysis demonstrated circulation of subgroup B viruses with predominance of lineage B2. Nucleotide sequence identity within lineage B1 was 98.8%–99.7% and higher than that in lineage B2 (94.3%–100%). Three new amino acid substitutions (T223N, R229K, and D280N) of lineage B2 were observed. Conclusion. HMPV is a major viral pathogen in the Egyptian population especially in children. During 2007-2008, predominantly HMPV B2 circulated in Upper Egypt. Mona S. Embarek Mohamed, Janine Reiche, Sonja Jacobsen, Amany G. Thabit, Mohamed S. Badary, Wolfram Brune, Brunhilde Schweiger, and Ahmed H. Osmann Copyright © 2014 Mona S. Embarek Mohamed et al. All rights reserved. Simultaneous Production of Biosurfactants and Bacteriocins by Probiotic Lactobacillus casei MRTL3 Wed, 29 Jan 2014 00:00:00 +0000 Lactic acid bacteria (LAB) are ubiquitous and well-known commensal bacteria in the human and animal microflora. LAB are extensively studied and used in a variety of industrial and food fermentations. They are widely used for humans and animals as adjuvants, probiotic formulation, and dietary supplements and in other food fermentation applications. In the present investigation, LAB were isolated from raw milk samples collected from local dairy farms of Haryana, India. Further, the isolates were screened for simultaneous production of biosurfactants and bacteriocins. Biosurfactant produced was found to be a mixture of lipid and sugar similar to glycolipids. The bacteriocin obtained was found to be heat stable (5 min at 100°C). Further, DNA of the strain was extracted and amplified by the 16S rRNA sequencing using universal primers. The isolate Lactobacillus casei MRTL3 was found to be a potent biosurfactant and bacteriocin producer. It seems to have huge potential for food industry as a biopreservative and/or food ingredient. Deepansh Sharma and Baljeet Singh Saharan Copyright © 2014 Deepansh Sharma and Baljeet Singh Saharan. All rights reserved. Effect of Noradrenaline on the Virulence Properties of Campylobacter Species Tue, 28 Jan 2014 08:49:10 +0000 Campylobacter species cause a spectrum of illnesses in humans. The type of illness and the outcome is dependent on the virulence of the infecting pathogen strain and host immune status. Acute stress can seriously compromise host immunity and increase susceptibility to infection. Noradrenaline (NA) is a stress hormone. Several studies have shown that it stimulated growth and increased the pathogenicity of organisms including E. coli and Campylobacter jejuni. However, the effect of NA on other Campylobacter species is unknown. We have examined the effect of NA on growth rate, motility, invasion of T84 epithelial cells, and colonisation of chickens by diverse Campylobacter species. Campylobacter cultures grown with NA had reduced lag phases, increased growth rates, and higher final optical densities than controls. The motility of Campylobacter was also significantly increased in the presence of noradrenaline. Some of the Campylobacter strains tested also showed increased invasion of T84 epithelial cells, greater breakdown of tight junctions, and an enhanced potential to colonise chickens. Our results show that noradrenaline-induced enhancement of virulence of Campylobacter can influence the outcome of infection. Sree V. Aroori, Tristan A. Cogan, and Tom J. Humphrey Copyright © 2014 Sree V. Aroori et al. All rights reserved. Evaluation of Phytase Producing Bacteria for Their Plant Growth Promoting Activities Thu, 23 Jan 2014 06:40:21 +0000 Bacterial inoculants are known to possess plant growth promoting abilities and have potential as liquid biofertilizer application. Four phytase producing bacterial isolates (phytase activity in the range of 0.076–0.174 U/mL), identified as Advenella species (PB-05, PB-06, and PB-10) and Cellulosimicrobium sp. PB-09, were analyzed for their plant growth promoting activities like siderophore production, IAA production, HCN production, ammonia production, phosphate solubilization, and antifungal activity. All isolates were positive for the above characteristics except for HCN production. The solubilization index for phosphorus on Pikovskaya agar plates was in the range of 2–4. Significant amount of IAA (7.19 to 35.03 μg/mL) production and solubilized phosphate (189.53 to 746.84 μg/mL) was noticed by these isolates at different time intervals. Besides that, a greenhouse study was also conducted with Indian mustard to evaluate the potential of these isolates to promote plant growth. Effect of seed bacterization on various plant growth parameters and P uptake by plant were used as indicators. The plant growth promoting ability of bacterial isolates in pot experiments was correlated to IAA production, phosphate solubilization, and other in vitro tests. On the basis of present findings, isolate PB-06 was most promising in plant growth promotion with multiple growth promoting characteristics. Prashant Singh, Vinod Kumar, and Sanjeev Agrawal Copyright © 2014 Prashant Singh et al. All rights reserved. High Level Expression and Purification of Atl, the Major Autolytic Protein of Staphylococcus aureus Sun, 19 Jan 2014 07:25:10 +0000 Staphylococcus aureus is a major human and animal pathogen. Autolysins regulate the growth, turnover, cell lysis, biofilm formation, and the pathogenicity of S. aureus. Atl is the major autolysin in S. aureus. The biochemical and structural studies of staphylococcal Atl have been limited due to difficulty in cloning, high level overexpression, and purification of this protein. This study describes successful cloning, high level over-expression, and purification of two forms of fully functional Atl proteins. These pure proteins can be used to study the functional and structural properties of this important protein. Vineet K. Singh Copyright © 2014 Vineet K. Singh. All rights reserved. Hormetic Concentrations of Hydrogen Peroxide but Not Ethanol Induce Cross-Adaptation to Different Stresses in Budding Yeast Tue, 14 Jan 2014 12:39:33 +0000 The biphasic-dose response of microorganisms to hydrogen peroxide is a phenomenon of particular interest in hormesis research. In different animal models, the dose-response curve for ethanol is also nonlinear showing an inhibitory effect at high doses but a stimulatory effect at low doses. In this study, we observed the hormetic-dose response to ethanol in budding yeast S. cerevisiae. Cross-protection is a phenomenon in which exposure to mild stress results in the acquisition of cellular resistance to lethal stress induced by different factors. Since both hydrogen peroxide and ethanol at low concentrations were found to stimulate yeast colony growth, we evaluated the role of one substance in cell cross-adaptation to the other substance as well as some weak organic acid preservatives. This study demonstrates that, unlike ethanol, hydrogen peroxide at hormetic concentrations causes cross-resistance of S. cerevisiae to different stresses. The regulatory protein Yap1 plays an important role in the hormetic effects by low concentrations of either hydrogen peroxide or ethanol, and it is involved in the yeast cross-adaptation by low sublethal doses of hydrogen peroxide. Halyna M. Semchyshyn Copyright © 2014 Halyna M. Semchyshyn. All rights reserved. Occurrence of Bordetella Infection in Pigs in Northern India Sun, 12 Jan 2014 00:00:00 +0000 Bordetella bronchiseptica infection causing atrophic rhinitis in pigs is reported from almost all countries. In the present study, occurrence of Bordetella infection in apparently healthy pigs was determined in 392 pigs sampled to collect 358 serum samples and 316 nasal swabs from Northern India by conventional bacterioscopy, detection of antigen with multiplex polymerase chain reaction (mPCR), and detection of antibodies with microagglutination test (MAT) and enzyme linked immune-sorbent assay (ELISA). Bordetella bronchiseptica could be isolated from six (1.92%) nasal swabs. Although isolates varied significantly in their antimicrobial sensitivity, they had similar plasmid profile. The genus specific and species specific amplicons were detected from 8.2% and 4.4% nasal swabs using mPCR with alc gene (genus specific) and fla gene and fim2 gene (species specific) primers, respectively. Observations revealed that there may be other bordetellae infecting pigs because about 50% of the samples positive using mPCR for genus specific amplicons failed to confirm presence of B. bronchiseptica. Of the pig sera tested with MAT and ELISA for Bordetella antibodies, 67.6% and 86.3% samples, respectively, were positive. For antigen detection mPCR was more sensitive than conventional bacterioscopy while for detection of antibodies neither of the two tests (MAT and ELISA) had specificity in relation to antigen detection. Study indicated high prevalence of infection in swine herds in Northern India. Sandeep Kumar, Bhoj R. Singh, Monika Bhardwaj, and Vidya Singh Copyright © 2014 Sandeep Kumar et al. All rights reserved. Molecular and Technological Characterization of Saccharomyces cerevisiae Strains Isolated from Natural Fermentation of Susumaniello Grape Must in Apulia, Southern Italy Thu, 09 Jan 2014 09:34:46 +0000 The characterization of autochthonous Saccharomyces cerevisiae strains is an important step towards the conservation and employment of microbial biodiversity. The utilization of selected autochthonous yeast strains would be a powerful tool to enhance the organoleptic and sensory properties of typical regional wines. In fact, indigenous yeasts are better tailored to a particular must and because of this they are able to praise the peculiarities of the derived wine. The present study described the biodiversity of indigenous S. cerevisiae strains isolated from natural must fermentations of an ancient and recently rediscovered Apulian grape cultivar, denoted as “Susumaniello.” The yeast strains denoted by the best oenological and technological features were identified and their fermentative performances were tested by either laboratory assay. Five yeast strains showed that they could be excellent candidates for the production of industrial starter cultures, since they dominated the fermentation process and produced wines characterized by peculiar oenological and organoleptic features. Mariana Tristezza, Lorenagostina Fantastico, Cosimo Vetrano, Gianluca Bleve, Daniela Corallo, Francesco Grieco, Giovanni Mita, and Francesco Grieco Copyright © 2014 Mariana Tristezza et al. All rights reserved. Gastrointestinal Bacterial and Methanogenic Archaea Diversity Dynamics Associated with Condensed Tannin-Containing Pine Bark Diet in Goats Using 16S rDNA Amplicon Pyrosequencing Thu, 02 Jan 2014 13:22:17 +0000 Eighteen Kiko-cross meat goats () were used to collect gastrointestinal (GI) bacteria and methanogenic archaea for diversity measures when fed condensed tannin-containing pine bark (PB). Three dietary treatments were tested: control diet (0% PB and 30% wheat straw (WS); 0.17% condensed tannins (CT) dry matter (DM)); 15% PB and 15% WS (1.6% CT DM), and 30% PB and 0% WS (3.2% CT DM). A 16S rDNA bacterial tag-encoded FLX amplicon pyrosequencing technique was used to characterize and elucidate changes in GI bacteria and methanogenic archaea diversity among the diets. Proteobacteria was the most dominant phylum in goats with mean relative abundance values ranging from 39.7 (30% PB) to 46.5% (control) and 47.1% (15% PB). Other phyla individually accounted for fewer than 25% of the relative abundance observed. Predominant methanogens were Methanobrevibacter (75, 72, and 49%), Methanosphaera (3.3, 2.3, and 3.4%), and Methanobacteriaceae (1.2, 0.6, and 0.7%) population in control, 15, and 30% PB, respectively. Among methanogens, Methanobrevibacter was linearly decreased () with increasing PB supplementation. These results indicate that feeding PB selectively altered bacteria and methanogenic archaeal populations in the GI tract of goats. Byeng R. Min, Sandra Solaiman, Raymon Shange, and Jong-Su Eun Copyright © 2014 Byeng R. Min et al. All rights reserved. Taxonomy and Polyphasic Characterization of Alkaline Amylase Producing Marine Actinomycete Streptomyces rochei BTSS 1001 Mon, 30 Dec 2013 18:07:20 +0000 Actinomycetes isolated from marine sediments along the southeast coast of Bay of Bengal were investigated for amylolytic activity. Marine actinomycete BTSS 1001 producing an alkaline amylase was identified from marine sediment of Diviseema coast, Bay of Bengal. The isolate produced alkaline amylase with maximum amylolytic activity at pH 9.5 at 50°C. The organism produced white to pale grey substrate mycelium and grayish aerial mycelium with pinkish brown pigmentation. A comprehensive study of morphological, physiological parameters, cultural characteristics, and biochemical studies was performed. The presence of iso-C15 : 0, anteiso-C15 : 0, iso-C16 : 0, and anteiso-C17 : 0 as the major cellular fatty acids, LL-diaminopimelic acid as the characteristic cell wall component, and menaquinones MK-9H(6) and MK-9H(8) as the major isoprenoid quinones is attributed to the strain BTSS 1001 belonging to the genus Streptomyces. Comparison of 16S rRNA gene sequences showed that strain BTSS 1001 exhibited the highest similarities to the type strains of Streptomyces rochei (99%), Streptomyces plicatus (99%), and Streptomyces enissocaesilis (99%). Using the polyphasic taxonomical approach and phenotypic characteristic studies, the isolate BTSS 1001 was characterized as marine actinomycete Streptomyces rochei. Aparna Acharyabhatta, Siva Kumar Kandula, and Ramana Terli Copyright © 2013 Aparna Acharyabhatta et al. All rights reserved. Prospective Zinc Solubilising Bacteria for Enhanced Nutrient Uptake and Growth Promotion in Maize (Zea mays L.) Mon, 30 Dec 2013 12:58:22 +0000 Zinc (Zn) is one of the essential micronutrients required for optimum plant growth. Substantial quantity of applied inorganic zinc in soil is converted into unavailable form. Zinc solubilising bacteria are potential alternates for zinc supplement. Among 10 strains screened for Zn solubilisation, P29, P33, and B40 produced 22.0 mm clear haloes on solid medium amended with ZnCO3. Similarly, P17 and B40 showed 31.0 mm zone in ZnO incorporated medium. P29 and B40 showed significant release of Zn in broth amended with ZnCO3 (17 and 16.8 ppm) and ZnO (18 and 17 ppm), respectively. The pH of the broth was almost acidic in all the cases ranging from 3.9 to 6.1 in ZnCO3 and from 4.1 to 6.4 in ZnO added medium. Short term pot culture experiment with maize revealed that seed bacterization with P29 @ 10 g·kg−1 significantly enhanced total dry mass (12.96 g) and uptake of N (2.268%), K (2.0%), Mn (60 ppm), and Zn (278.8 ppm). Praveen Kumar Goteti, Leo Daniel Amalraj Emmanuel, Suseelendra Desai, and Mir Hassan Ahmed Shaik Copyright © 2013 Praveen Kumar Goteti et al. All rights reserved. Biofilm Formation among Clinical and Food Isolates of Listeria monocytogenes Sun, 29 Dec 2013 08:46:08 +0000 Objective. A total of 725 Listeria monocytogenes isolates, 607 from various foods and 118 from clinical cases of listeriosis, were investigated concerning their ability to form biofilms, at 4°C during 5 days and at 37°C during 24 h. Methods. Biofilm production was carried out on polystyrene tissue culture plates. Five L. monocytogenes isolates were tested for biofilm formation after being exposed to acidic and osmotic stress conditions. Results. Significant differences () between clinical and food isolates were observed. At 37°C for 24 h, most food isolates were classified as weak or moderate biofilm formers whereas all the clinical isolates were biofilm producers, although the majority were weak. At 4°C during 5 days, 65 and 59% isolates, from food and clinical cases, respectively, were classified as weak. After both sublethal stresses, at 37°C just one of the five isolates tested was shown to be more sensitive to subsequent acidic exposure. However, at 4°C both stresses did not confer either sensitivity or resistance. Conclusions. Significant differences between isolates origin, temperature, and sublethal acidic stress were observed concerning the ability to form biofilms. Strain, origin, and environmental conditions can determine the level of biofilm production by L. monocytogenes isolates. Joana Barbosa, Sandra Borges, Ruth Camilo, Rui Magalhães, Vânia Ferreira, Isabel Santos, Joana Silva, Gonçalo Almeida, and Paula Teixeira Copyright © 2013 Joana Barbosa et al. All rights reserved. Formulation and Statistical Optimization of Culture Medium for Improved Production of Antimicrobial Compound by Streptomyces sp. JAJ06 Mon, 23 Dec 2013 09:49:45 +0000 Streptomyces sp. JAJ06 is a seawater-dependent antibiotic producer, previously isolated and characterised from an Indian coastal solar saltern. This paper reports replacement of seawater with a defined salt formulation in production medium and subsequent statistical media optimization to ensure consistent as well as improved antibiotic production by Streptomyces sp. JAJ06. This strain was observed to be proficient to produce antibiotic compound with incorporation of chemically defined sodium-chloride-based salt formulation instead of seawater into the production medium. Plackett-Burman design experiment was applied, and three media constituents, starch, KBr, and CaCO3, were recognised to have significant effect on the antibiotic production of Streptomyces JAJ06 at their individual levels. Subsequently, Response surface methodology with Box-Behnken design was employed to optimize these influencing medium constituents for the improved antibiotic production of Streptomyces sp. JAJ06. A total of 17 experiments were conducted towards the construction of a quadratic model and a second-order polynomial equation. Optimum levels of medium constituents were obtained by analysis of the model and numerical optimization method. When the strain JAJ06 was cultivated in the optimized medium, the antibiotic activity was increased to 173.3 U/mL, 26.8% increase as compared to the original (136.7 U/mL). This study found a useful way to cultivate Streptomyces sp. JAJ06 for enhanced production of antibiotic compound. Polpass Arul Jose, Kunjukrishnan Kamalakshi Sivakala, and Solomon Robinson David Jebakumar Copyright © 2013 Polpass Arul Jose et al. All rights reserved. Seasonal Levels of the Vibrio Predator Bacteriovorax in Atlantic, Pacific, and Gulf Coast Seawater Sun, 22 Dec 2013 09:03:53 +0000 Bacteriovorax were quantified in US Atlantic, Gulf, and Pacific seawater to determine baseline levels of these predatory bacteria and possible seasonal fluctuations in levels. Surface seawater was analyzed monthly for 1 year from Kailua-Kona, Hawaii; the Gulf Coast of Alabama; and four sites along the Delaware Bay. Screening for Bacteriovorax was performed on lawns of V. parahaemolyticus host cells. Direct testing of 7.5 mL portions of seawater from the Atlantic, Pacific, and Gulf coasts gave mean annual counts ≤12.2 PFU. Spikes in counts were observed at 3 out of 4 sites along the Delaware Bay 1 week after Hurricane Sandy. A comparison of summer versus winter counts showed significantly more Bacteriovorax () in the Delaware Bay during the summer and significantly more () in the Gulf during the winter, but no significant seasonal differences () for Hawaiian seawater. Bacteriovorax counts only correlated with seawater salinity and temperature at one Delaware site ( and , resp.). There was a relatively strong negative correlation between temperature and Bacteriovorax levels () for Gulf seawater. Selected isolates were sequenced and identified by phylogenetic analysis as Bacteriovorax clusters IX, X, XI, and XII. Gary P. Richards, Michael A. Watson, E. Fidelma Boyd, William Burkhardt III, Ronald Lau, Joseph Uknalis, and Johnna P. Fay Copyright © 2013 Gary P. Richards et al. All rights reserved. Epidemiology and Changes in Patient-Related Factors from 1997 to 2009 in Clinical Yeast Isolates Related to Dermatology, Gynaecology, and Paediatrics Wed, 11 Dec 2013 08:43:34 +0000 From 1997 to 2009, 1,862 dermatology, gynaecology, and paediatrics (DGP) associated clinical yeast isolates were analysed for species occurrence, specimen origin and type, (multi-) resistance pattern, and testing period. The top seven of the isolated DGP-associated species remained the same as compared to total medical wards, with Candida albicans (45%) as most frequent pathogen. However, the DGP wards and DGP ICUs showed species-specific profiles; that is, the species distribution is clinic-specific similar and however differs in their percentage from ward to ward. By applying the “one fungus one name” principle, respectively, the appropriate current taxonomic species denominations, it has been shown that no trend to emerging species from 1998 to 2008 could be detected. In particular the frequently isolated non-Candida albicans species isolated in the DGP departments have already been detected in or before 1997. As yeasts are part of the cutaneous microbiota and play an important role as opportunistic pathogens for superficial infections, proper identification of the isolates according to the new nomenclature deems to be essential for specific and calculated antifungal therapy for yeast-like DGP-related infectious agents. Viktor Czaika, Pietro Nenoff, Andreas Glöckner, Wolfgang Fegeler, Karsten Becker, and Arno F. Schmalreck Copyright © 2013 Viktor Czaika et al. All rights reserved. Serendipitous Isolation of Non-Vibrio Bacterial Strains Carrying the Cholera Toxin Gene from Environmental Waters in Indonesia Tue, 03 Dec 2013 09:27:42 +0000 We initially attempted to isolate a Vibrio cholerae O1 El Tor biotype that carries a novel variant of the cholera toxin gene (ctxAB) from environmental waters of Indonesia, where the seventh cholera pandemic by V. cholerae O1 El Tor biotype began. Nested PCR targeting the gene revealed that a total of eight strains were found to carry ctxAB. However, sequencing of the 16S rRNA genes of these isolates showed they were not V. cholerae but were either Klebsiella, Enterobacter, Pantoea, or Aeromonas. Subsequent nested PCR assays targeting all genes known to be encoded on the CTX phage (i.e., zot, ace, orfU, cep, rstB, rstA, and rstR) showed that one isolate belonged to the Enterobacter genus carried all the genes tested, while the other isolates lacked either 2, 3, or 5 of the genes. This evidence suggests that phages with ctxAB are genetically diverse and can infect not only V. cholerae and V. mimicus but also other species and genera in the form of a pseudolysogen. Yusuke Shibata, Ryohei Nomoto, Garry Cores de Vries, and Ro Osawa Copyright © 2013 Yusuke Shibata et al. All rights reserved. Towards Multitarget Testing in Molecular Microbiology Mon, 25 Nov 2013 17:50:46 +0000 Advantages of PCR assays over more conventional culture-based diagnostics include significantly higher sensitivities and shorter turnaround times. They are particularly useful when patient treatment has already been initiated or for specimens that may contain microorganisms that are slow-growing, difficult to culture, or for which culture methods do not exist. However, due to genome variability, single target testing might lead to false-negative results. This paper focuses on examples from our own experiences and the literature to provide insight into the limitations of single target testing in molecular biology. Lessons learned from these experiences include the careful design of diagnostic assays, preferably multitargeted, the importance of investigating the incidence and epidemiology of infection in detail, the frequent participation in appropriate quality assurance schemes, and the importance of continuous attentiveness by investigators when confronted with inconsistent results. In conclusion, multitargeted testing in microbiological molecular assays should be a rule. Deborah Steensels, Anne Vankeerberghen, and Hans De Beenhouwer Copyright © 2013 Deborah Steensels et al. All rights reserved.