ISRN Microbiology The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Function and Evolution of the Sox Multienzyme Complex in the Marine Gammaproteobacterium Congregibacter litoralis Mon, 31 Mar 2014 06:20:27 +0000 Core sets of sox genes were detected in several genome sequenced members of the environmental important OM60/NOR5 clade of marine gammaproteobacteria. However, emendation of media with thiosulfate did not result in stimulation of growth in two of these strains and cultures of Congregibacter litoralis DSM did not oxidize thiosulfate to sulfate in concentrations of one mmol L−1 or above. On the other hand, a significant production of sulfate was detected upon growth with the organic sulfur compounds, cysteine and glutathione. It was found that degradation of glutathione resulted in the formation of submillimolar amounts of thiosulfate in the closely related sox-negative strain Chromatocurvus halotolerans DSM . It is proposed that the Sox multienzyme complex in Congregibacter litoralis and related members of the OM60/NOR5 clade is adapted to the oxidation of submillimolar amounts of thiosulfate and nonfunctional at higher concentrations of reduced inorganic sulfur compounds. Pelagic bacteria thriving in the oxic zones of marine environments may rarely encounter amounts of thiosulfate, which would allow its utilization as electron donor for lithoautotrophic or mixotrophic growth. Consequently, in evolution the Sox multienzyme complex in some of these bacteria may have been optimized for the effective utilization of trace amounts of thiosulfate generated from the degradation of organic sulfur compounds. Stefan Spring Copyright © 2014 Stefan Spring. All rights reserved. Prevalence and Genetic Characterization of Carbapenem- and Polymyxin-Resistant Acinetobacter baumannii Isolated from a Tertiary Hospital in Terengganu, Malaysia Wed, 19 Mar 2014 07:09:19 +0000 Nosocomial infection caused by Acinetobacter baumannii is of great concern due to its increasing resistance to most antimicrobials. In this study, 54 nonrepeat isolates of A. baumannii from the main tertiary hospital in Terengganu, Malaysia, were analyzed for their antibiograms and genotypes. Out of the 54 isolates, 39 (72.2%) were multidrug resistant (MDR) and resistant to carbapenems whereas 14 (25.9%) were categorized as extensive drug resistant (XDR) with additional resistance to polymyxin B, the drug of “last resort.” Pulsed-field gel electrophoresis analyses showed that the polymyxin-resistant isolates were genetically diverse while the carbapenem-resistant isolates were clonally related. The 14 XDR isolates were further investigated for mutations in genes known to mediate polymyxin resistance, namely, pmrCAB, and the lipopolysaccharide biosynthesis genes, lpxA, lpxC, lpxD, and lpsB. All 14 isolates had a P102H mutation in pmrA with no mutation detected in pmrC and pmrB. No mutation was detected in lpxA but each polymyxin-resistant isolate had 2–4 amino acid substitutions in lpxD and 1-2 substitutions in lpxC. Eight resistant isolates also displayed a unique H181Y mutation in lpsB. The extent of polymyxin resistance is of concern and the novel mutations discovered here warrant further investigations. Soo-Sum Lean, Zarizal Suhaili, Salwani Ismail, Nor Iza A. Rahman, Norlela Othman, Fatimah Haslina Abdullah, Zakaria Jusoh, Chew Chieng Yeo, and Kwai-Lin Thong Copyright © 2014 Soo-Sum Lean et al. All rights reserved. Investigation of Bacterial Cellulose Biosynthesis Mechanism in Gluconoacetobacter hansenii Sun, 16 Mar 2014 00:00:00 +0000 The present study explores the mechanism of cellulose biosynthesis in Gluconoacetobacter hansenii. The cellulose synthase enzyme was purified as membrane fraction and solubilized by treatment with 0.1% digitonin. The enzyme was separated by native-gel electrophoresis and β-D-glucan analysis was carried out using in vitro gel assay. The cellulose synthase has glycoprotein nature and composed two polypeptide subunits of 93 KDa and 85 KDa. The confirmation of β-1,4-glucan (cellulose) was performed in whole and hydrolyzed monomeric sugar form. Tinopal and Congo red were used for cellulose detection on the gel. Thus the in vitro cellulose synthesis assay with cell free enzyme fraction was attempted to improve the understanding of cellulose biosynthesis. Bhavna V. Mohite and Satish V. Patil Copyright © 2014 Bhavna V. Mohite and Satish V. Patil. All rights reserved. Emergence of blaTEM Type Extended-Spectrum β-Lactamase Producing Salmonella spp. in the Urban Area of Bangladesh Mon, 10 Mar 2014 09:46:18 +0000 Salmonellosis, an acute invasive enteric infection, is endemic in Bangladesh. We analyzed 128,312 stool samples of diarrheal patients to identify Salmonella spp. during 2005–2013. A total of 2120 (1.7%) Salmonella spp. were isolated and the prevalence of Salmonella spp. decreased significantly over time (2→1%, ). Among the typhoidal Salmonella (TS) serogroups, S. Typhi was predominant (404, [65.1%]) followed by S. Paratyphi B (139, [22.4%]) and S. Paratyphi A (78, [12.6%]). Of the nontyphoidal Salmonella (NTS) isolates, the serogroup C1 (560, [37%]) was predominant followed by B (379, [25%]), C2 (203, [14%]), E (127, [9%]), and D (94, [6%]). Most of the resistance was found towards nalidixic acid (40%), ampicillin (36%), cotrimoxazole (20%), chloramphenicol (13%), ciprofloxacin (4%), and ceftriaxone (4%). Interestingly, 32% of the isolates showed reduced susceptibility to Cip. Multiantibiotic resistance (MAR, ≥3 drugs) was more common among TS than NTS strains (). Among the representative ceftriaxone-resistant isolates, gene was detected among 88% (7/8) of the strains, whereas only one strain of S. Typhi was positive for both and genes. The study reflects higher prevalence of MAR Salmonella spp. and is the first to report the gene mediated ESBL production among Salmonellae in Bangladesh. Emergence of MAR Salmonella spp. in particular ESBL strains should be considered a public health concern. Dilruba Ahmed, Abu Iftiaf Md. Salah Ud-Din, Syeda Umme Habiba Wahid, Razib Mazumder, Kamrun Nahar, and Anowar Hossain Copyright © 2014 Dilruba Ahmed et al. All rights reserved. Comparative Assessment of Factors Involved in Acetoin Synthesis by Bacillus subtilis 168 Mon, 10 Mar 2014 09:05:00 +0000 Acetoin is widely used as flavor agent and serves as a precursor for chemical synthesis. Here we focused on identifying the best physiological conditions (initial substrate concentrations, pH, temperature, and agitation) for enhanced acetoin accumulation by Bacillus subtilis 168. The optimal physiological conditions support maximum acetoin accumulation by minimizing byproduct (acetate and butanediol) synthesis and a maximum of 75% enhancement in acetoin yield could be achieved. Additionally, the effect of change in ALS (acetolactate synthase) and ALDC (acetolactate decarboxylase) activities was evaluated on acetoin accumulation. Increasing ALS and ALDC enzyme activities led to efficient utilization of pyruvate towards acetoin accumulation and about 80% enhancement in acetoin accumulation was observed. Pratibha Sharma and Santosh Noronha Copyright © 2014 Pratibha Sharma and Santosh Noronha. All rights reserved. Prevalence, Clinical Features, and Outcome of Pseudomonas Bacteremia in Under-Five Diarrheal Children in Bangladesh Sun, 09 Mar 2014 06:54:53 +0000 We sought to evaluate the prevalence, associated factors, and outcome of under-five diarrheal children with either sex having Pseudomonas bacteremia. A retrospective chart review of under-five diarrheal children admitted to the Dhaka Hospital of the International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), from January 2011 to December 2011 was performed using an online hospital management system. Children with Pseudomonas bacteremia constituted the cases (n = 31), and the controls (n = 124), without Pseudomonas bacteremia, were randomly selected. The prevalence of Pseudomonas bacteremia was 1% (31/5,179). The Pseudomonas was multidrug resistant but was 84% sensitive to ceftazidime and 100% to imipenem. The case-fatality rate was significantly higher among the cases than the controls (26% versus 5%; P = 0.003). In logistic regression analysis, after adjusting for potential confounders such as severe wasting, severe underweight, severe pneumonia, and young age (11.71 (4.0, 18.0) months), the cases more often presented with absent peripheral pulses in absence of dehydration (95% CI = 2.31–24.45) on admission. This finding underscores the importance of early identification of this simple clinical sign to ensure prompt management including fluid resuscitation and broad spectrum antibiotics to help reduce morbidity and mortality in such children, especially in resource-poor settings. Farhana Akram, Mark A.C. Pietroni, Pradip Kumar Bardhan, Samira Bibi, and Mohammod Jobayer Chisti Copyright © 2014 Farhana Akram et al. All rights reserved. Influence of Stress Connected with Moving to a New Farm on Potentially MAP-Infected Mouflons Tue, 04 Mar 2014 12:34:22 +0000 There is no European legislation concerning paratuberculosis that requires that imported animals be kept in quarantine and commonly they are directly released into areas with other animals. In this study, detection of latent infection of paratuberculosis in healthy mouflons previously diagnosed as paratuberculosis-free, but originating from a real time quantitative PCR- (qPCR-) positive herd, occurred after their transport to a new farm. During a twelve-day quarantine period, all mouflons irregularly shed Mycobacterium avium subsp. paratuberculosis (MAP) in faeces, and in a small number of cases also in milk. After the animals were released from quarantine, MAP was detected for a further two days, after which, testing was negative, except in one case. Therefore, the stress connected with transport, novel environment, dietary change, or limited area with high density of animals might have contributed to the induction of paratuberculosis and the shedding of MAP from the animals, previously diagnosed as MAP-negative. According to these results, the keeping of imported animals in quarantine and their examination for MAP presence not only before the transport but also afterwards should be recommended. The designation of a particular area of a farm as a quarantine enclosure could help to mitigate the impact of stress caused by a confined space with a high density of animals. Radka Pribylova-Dziedzinska, Iva Slana, Jiri Lamka, and Ivo Pavlik Copyright © 2014 Radka Pribylova-Dziedzinska et al. All rights reserved. Antimicrobial Resistance of Salmonella enterica Isolates from Tonsil and Jejunum with Lymph Node Tissues of Slaughtered Swine in Metro Manila, Philippines Tue, 04 Mar 2014 12:09:43 +0000 Due to frequent antibiotic exposure, swine is now recognized as potential risk in disseminating drug-resistant Salmonella enterica strains. This study thus subjected 20 randomly selected S. enterica isolates from tonsil and jejunum with lymph node (JLN) tissues of swine slaughtered in Metro Manila, Philippines, to VITEK 2 antimicrobial susceptibility testing (AST). The test revealed all 20 isolates had resistance to at least one antimicrobial agent, in which highest occurrence of resistance was to amikacin (100%), cefazolin (100%), cefuroxime (100%), cefuroxime axetil (100%), cefoxitin (100%), and gentamicin (100%), followed by ampicillin (50%), and then by sulfamethoxazole trimethoprim (30%). Three multidrug-resistant (MDR) isolates were detected. The sole S. enterica serotype Enteritidis isolate showed resistance to 12 different antibiotics including ceftazidime, ceftriaxone, amikacin, gentamicin, and tigecycline. This study is the first to report worldwide on the novel resistance to tigecycline of MDR S. enterica serotype Enteritidis isolated from swine tonsil tissues. This finding poses huge therapeutic challenge since MDR S. enterica infections are associated with increased rate of hospitalization or death. Thus, continual regulation of antimicrobial use in food animals and prediction of resistant serotypes are crucial to limit the spread of MDR S. enterica isolates among hogs and humans. Kamela Charmaine S. Ng and Windell L. Rivera Copyright © 2014 Kamela Charmaine S. Ng and Windell L. Rivera. All rights reserved. Prevalence of Haemoplasma Infections in Stray Cats in Northern Italy Sun, 23 Feb 2014 09:10:02 +0000 This study investigated the prevalence of feline haemoplasma infections in a number of stray cat colonies in Milan, Northern Italy. Blood samples from 260 stray cats were evaluated, with conventional PCR, for the presence of DNA associated with Mycoplasma haemofelis (Mhf) and “Candidatus Mycoplasma haemominutum” (CMhm). Odd ratios (OR) were calculated to identify risk factors for haemoplasma infections. PCR was positive in 86 out of 260 subjects (33.1%), with a prevalence of 10.8% (28/260 cats) for Mhf and 22.3% (58/260 cats) for CMhm. No coinfections were registered. There were significant associations between infections and season of sampling, that is, a negative association between winter sampling and a haemoplasma positive status , , or CMhm positive status , . Haemoplasma infections are common in stray cats in Milan. Thus, domestic cats with outdoor access should be routinely monitored and treated for ectoparasites to minimize risks of disease acquisition. Moreover, as these infections are transmitted via blood, feline blood donors from this area should be screened by PCR and preferably be drawn from a population of indoor cats regularly treated for fleas. Eva Spada, Daniela Proverbio, Paola Galluzzo, Alessandra Della Pepa, Giada Bagnagatti De Giorgi, Roberta Perego, and Elisabetta Ferro Copyright © 2014 Eva Spada et al. All rights reserved. Occurrence of Methicillin Resistant and Enterotoxigenic Staphylococcus aureus in Traditional Cheeses in the North West of Iran Thu, 13 Feb 2014 13:58:25 +0000 Traditional dairy products are potential sources of a variety of microorganisms which participate in food poisoning. Staphylococcus aureus is a conspicuous example of toxigenic bacteria causative for food-borne diseases. Moreover, resistance to methicillin is a prominent index in food hygiene studies. In the present study, we have aimed at characterization and identification of enterotoxigenic methicillin resistant S. aureus (MRSA) isolated from traditional cheeses in Azerbaijan region in the northwest of Iran during 2012. A number of phenotypical and molecular assays were utilized for screening of S. aureus. Subsequently, the prevalence of the genes responsible for the five staphylococcal enterotoxins (SEA-SEE) and also methicillin resistance gene was assessed. The outcomes of phenotypical methods were in conformity with those of the molecular procedures. The results indicated that 16% of cheese samples were contaminated by S. aureus. 110 isolates were authenticated by both phenotypical and molecular methods. All of the mentioned isolates were positive for coa, nuc, and 16S rDNA primers. 21% of these isolates were mecA positive and 60.8% of these MRSA were positive for SEs. Regarding the frequent outbreaks of enterotoxigenic MRSA, new hygiene policies and management practices should be considered to increase food safety and avoid extra treatment costs. Dariush Shanehbandi, Behzad Baradaran, Saeed Sadigh-Eteghad, and Habib Zarredar Copyright © 2014 Dariush Shanehbandi et al. All rights reserved. Mode of Action and Specificity of Bacillus thuringiensis Toxins in the Control of Caterpillars and Stink Bugs in Soybean Culture Mon, 20 Jan 2014 08:49:07 +0000 The bacterium Bacillus thuringiensis (Bt) produces delta-endotoxins that possess toxic properties and can be used as biopesticides, as well as a source of genes for the construction of transgenic plants resistant to insects. In Brazil, the introduction of Bt soybean with insecticidal properties to the velvetbean caterpillar, the main insect pest of soybean, has been seen a promising tool in the management of these agroecosystems. However, the increase in stink bug populations in this culture, in various regions of the country, which are not susceptible to the existing genetically modified plants, requires application of chemicals that damage the environment. Little is known about the actual toxicity of Bt to Hemiptera, since these insects present sucking mouthparts, which hamper toxicity assays with artificial diets containing toxins of this bacterium. In recent studies of cytotoxicity with the gut of different hemipterans, susceptibility in the mechanism of action of delta-endotoxins has been demonstrated, which can generate promising subsidies for the control of these insect pests in soybean. This paper aims to review the studies related to the selection, application and mode of action of Bt in the biological control of the major pest of soybean, Anticarsia gemmatalis, and an analysis of advances in research on the use of Bt for control hemipterans. Rogério Schünemann, Neiva Knaak, and Lidia Mariana Fiuza Copyright © 2014 Rogério Schünemann et al. All rights reserved. Canola Cake as a Potential Substrate for Proteolytic Enzymes Production by a Selected Strain of Aspergillus oryzae: Selection of Process Conditions and Product Characterization Wed, 25 Dec 2013 10:15:17 +0000 Oil cakes have excellent nutritional value and offer considerable potential for use in biotechnological processes that employ solid-state fermentation (SSF) for the production of high value products. This work evaluates the feasibility of using canola cake as a substrate for protease production by a selected strain of Aspergillus oryzae cultivated under SSF. The influences of the following process parameters were considered: initial substrate moisture content, incubation temperature, inoculum size, and pH of the buffer used for protease extraction and activity analysis. Maximum protease activity was obtained after cultivating Aspergillus oryzae CCBP 001 at 20°C, using an inoculum size of 107 spores/g in canola cake medium moistened with 40 mL of water to 100 g of cake. Cultivation and extraction under selected conditions increased protease activity 5.8-fold, compared to the initial conditions. Zymogram analysis of the enzymatic extract showed that the protease molecular weights varied between 31 and 200 kDa. The concentrated protease extract induced clotting of casein in 5 min. The results demonstrate the potential application of canola cake for protease production under SSF and contribute to the technological advances needed to increase the efficiency of processes designed to add value to agroindustrial wastes. Adriana C. Freitas, Ruann J. S. Castro, Maria A. Fontenele, Antonio S. Egito, Cristiane S. Farinas, and Gustavo A. S. Pinto Copyright © 2013 Adriana C. Freitas et al. All rights reserved. Characteristics of Multidrug Resistant Shigella and Vibrio cholerae O1 Infections in Patients Treated at an Urban and a Rural Hospital in Bangladesh Sun, 22 Dec 2013 13:34:09 +0000 We determined the frequency of multidrug resistant (MDR) infections with Shigella spp. and Vibrio cholerae O1 at an urban (Dhaka) and rural (Matlab) hospital in Bangladesh. We also compared sociodemographic and clinical features of patients with MDR infections to those with antibiotic-susceptible infections at both sites. Analyses were conducted using surveillance data from the International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), for the years 2000–2012. Compared to patients with antibiotic-susceptible for Shigella infections, those in Dhaka with MDR shigellosis were more likely to experience diarrhea for >24 hours, while, in Matlab, they were more likely to stay inhospital >24 hours. For MDR shigellosis, Dhaka patients were more likely than those in Matlab to have dehydration, stool frequency >10/day, and diarrheal duration >24 hours. Patients with MDR Vibrio cholerae O1 infections in Dhaka were more likely than those in Matlab to experience dehydration and stool frequency >10/day. Thus, patients with MDR shigellosis and Vibrio cholerae O1 infection exhibited features suggesting more severe illness than those with antibiotic-susceptible infections. Moreover, Dhaka patients with MDR shigellosis and Vibrio cholerae O1 infections exhibited features indicating more severe illness than patients in Matlab. Sumon Kumar Das, Erik H. Klontz, Ishrat J. Azmi, Abu I. M. S. Ud-Din, Mohammod Jobayer Chisti, Mokibul Hassan Afrad, Mohammad Abdul Malek, Shahnawaz Ahmed, Jui Das, Kaisar Ali Talukder, Mohammed Abdus Salam, Pradip Kumar Bardhan, Abu Syed Golam Faruque, and Karl C. Klontz Copyright © 2013 Sumon Kumar Das et al. All rights reserved. Growth of Mycobacterium avium subsp. paratuberculosis, Escherichia coli, and Salmonella Enteritidis during Preparation and Storage of Yogurt Mon, 16 Dec 2013 14:42:54 +0000 The purpose of this study was to determine the viability of Mycobacterium avium subsp. paratuberculosis (MAP), Escherichia coli (E. coli), and Salmonella Enteritidis (S. Enteritidis) during preparation and refrigerated storage of yogurt. Three yogurts were prepared using pasteurized commercial milk. Each yogurt was artificially contaminated with (1) MAP, (2) E. coli + S. Enteritidis, and (3) MAP + E. coli + S. Enteritidis. Samples were taken during and after the fermentation process until day 20 after inoculation. MAP was not detected during their preparation and short-term storage but was recuperated after starting at 180 min after inoculation storage. Live bacterial counts of E. coli, and S. Enteritidis increased during the first 24 hours, followed by a slight decrease towards the end of the study. In this study it was shown how MAP, E. coli, and S. Enteritidis resisted the acidic conditions generated during the preparation of yogurt and low storage temperatures. This work contributes to current knowledge regarding survival of MAP, E. coli, and S. Enteritidis during preparation and refrigerated storage of yogurt and emphasizes the need to improve hygiene measures to ensure the absence of these pathogenic microorganisms in dairy products. K. Cirone, Y. Huberman, C. Morsella, L. Méndez, M. Jorge, and F. Paolicchi Copyright © 2013 K. Cirone et al. All rights reserved. Screening of Fungi Isolated from Environmental Samples for Xylanase and Cellulase Production Thu, 12 Dec 2013 08:21:21 +0000 The aim of this work is to select filamentous fungal strains isolated from saw dust, soil, and decaying wood with the potential to produce xylanase and cellulase enzymes. A total of 110 fungi were isolated. Fifty-seven (57) of these fungi were isolated from soil samples, 32 from sawdust, and 19 from decaying wood. Trichoderma and Aspergillus had the highest relative occurrence of 42.6% and 40.8%, respectively. Trichoderma viride Fd18 showed the highest specific activity of 1.30 U mg−1 protein for xylanase, while the highest cellulase activity of 1.23 U mg−1 was shown by Trichoderma sp. F4. The isolated fungi demonstrated potential for synthesizing the hydrolytic enzymes. Mohammed Inuwa Ja’afaru Copyright © 2013 Mohammed Inuwa Ja’afaru. All rights reserved. Distribution and Antimicrobial Susceptibility Pattern of Bacterial Pathogens Causing Urinary Tract Infection in Urban Community of Meerut City, India Tue, 29 Oct 2013 10:23:23 +0000 Urinary tract infection is one of the common infections in the Indian community. Distribution and susceptibility of UTI-causing pathogens change according to time and place. This study was conducted to determine the distribution and antimicrobial susceptibility of uropathogens in the Indian community as well as to determine the effect of gender and age on the etiology of bacterial uropathogens. Clean catch midstream urine samples were collected from 288 patients of the age ranging from 15 to ≥48 years. Antimicrobial susceptibility was performed on all isolated bacteria by Kirby Bauer’s disc diffusion method. The multiple antibiotic resistance (MAR) index of each antibiotic was calculated. The UTI prevalence was 53.82% in patients; however, the prevalence was significantly higher in females than in males (females: 73.57%; males: 35.14%; ). Females within the age group of 26–36 years and elderly males of ≥48 years showed higher prevalence of UTI. Gram negative bacteria (90.32%) were found in high prevalence than Gram positive (9.68%). Escherichia coli (42.58%) was the most prevalent gram negative isolate. Nitrofurantoin (78.71%) was found the most resistant drug among all uropathogens. Tested carbapenems were found the most susceptible drug against isolated uropathogens which showed 92.26% and 84.52% susceptibility, respectively. Devanand Prakash and Ramchandra Sahai Saxena Copyright © 2013 Devanand Prakash and Ramchandra Sahai Saxena. All rights reserved. Acoustic Emission Signal of Lactococcus lactis before and after Inhibition with NaN3 and Infection with Bacteriophage c2 Mon, 21 Oct 2013 13:36:47 +0000 The detection of acoustic emission (AE) from Lactococcus lactis, ssp lactis is reported in which emission intensities are used to follow and define metabolic activity during growth in nutrient broths. Optical density (OD) data were also acquired during L. lactis growth at 32°C and provided insight into the timing of the AE signals relative to the lag, logarithmic, and stationary growth phases of the bacteria. The inclusion of a metabolic inhibitor, NaN3, into the nutrient broth eliminated bacteria metabolic activity according to the OD data, the absence of which was confirmed using AE data acquisition. The OD and AE data were also acquired before and after the addition of Bacteriophage c2 in L. lactis containing nutrient broths during the early or middle logarithmic phase; c2 phage m.o.i. (Multiplicity of infection) was varied to help differentiate whether the detected AE was from bacteria cells during lysis or from the c2 phage during genome injection into the cells. It is proposed that AE measurements using piezoelectric sensors are sensitive enough to detect bacteria at the amount near  cfu/mL, to provide real time data on bacteria metabolic activity and to dynamically monitor phage infection of cells. Debasish Ghosh, John M. Stencel, Clair D. Hicks, Fred Payne, and Didem Ozevin Copyright © 2013 Debasish Ghosh et al. All rights reserved. Growth Limiting pH, Water Activity, and Temperature for Neurotoxigenic Strains of Clostridium butyricum Mon, 30 Sep 2013 15:13:16 +0000 Some rare strains of Clostridium butyricum carry the gene encoding the botulinal type E neurotoxin and must be considered as possible hazards in certain types of food. The limiting growth conditions for C. butyricum were determined in peptone yeast glucose starch (PYGS) broth incubated anaerobically at 30°C for up to 42 days. The minimum pH values permitting growth depended on the acidulant and strain. Organic acids were more effective at inhibiting growth than HCl as expected. The lowest pH values at which growth of toxigenic and nontoxigenic strains of C. butyricum was observed in broth acidified with HCl were 4.1 and 4.2, respectively. In organic acids, however, the minimum pH varied between 4.4 and 5.1 depending on acid type and concentration. The minimum water activity for growth of toxigenic strains of C. butyricum was 0.96. The minimum growth temperatures of the toxigenic strains of C. butyricum (ca 10-11°C) were somewhat higher than for non-toxigenic ones (8°C). It was concluded that control of toxigenic C. butyricum in the food industry needs to allow for the greater pH tolerance of this species compared with proteolytic C. botulinum. Hamid B. Ghoddusi, Richard E. Sherburn, and Olusimbo O. Aboaba Copyright © 2013 Hamid B. Ghoddusi et al. All rights reserved. Receptors and Lethal Effect of Bacillus thuringiensis Insecticidal Crystal Proteins to the Anticarsia gemmatalis (Lepidoptera, Noctuidae) Mon, 30 Sep 2013 09:55:25 +0000 Bioassays with insecticidal crystal proteins (ICPs) from Bacillus thuringiensis have demonstrated that Cry1Aa, Cry1Ac, and Cry1Ba are the most active toxins on larvae of the Anticarsia gemmatalis. The toxins Cry1Da and Cry1Ea are less toxic, and toxins Cry2Aa are not active. Binding of these ICPs to midgut sections of the A. gemmatalis larvae was studied using streptavidin-mediated detection. The observed staining patterns showed that Cry1Aa and Cry1Ac bound to the brush border throughout the whole length of the midgut. However, the binding sites of Cry1Ba were not evenly distributed in the midgut microvilli. The in vivo assays against larvae of 2nd instar A. gemmatalis confirmed the results from the in vitro binding studies. These binding data correspond well with the bioassay results, demonstrating a correlation between receptors binding and toxicity of the tested ICPs in this insect. Lidia Mariana Fiuza, Neiva Knaak, Rogério Fernando Pires da Silva, and João Antônio Pêgas Henriques Copyright © 2013 Lidia Mariana Fiuza et al. All rights reserved. Viable but Nonculturable Bacteria: Food Safety and Public Health Perspective Thu, 26 Sep 2013 13:07:05 +0000 The viable but nonculturable (VBNC) state is a unique survival strategy of many bacteria in the environment in response to adverse environmental conditions. VBNC bacteria cannot be cultured on routine microbiological media, but they remain viable and retain virulence. The VBNC bacteria can be resuscitated when provided with appropriate conditions. A good number of bacteria including many human pathogens have been reported to enter the VBNC state. Though there have been disputes on the existence of VBNC in the past, extensive molecular studies have resolved most of them, and VBNC has been accepted as a distinct survival state. VBNC pathogenic bacteria are considered a threat to public health and food safety due to their nondetectability through conventional food and water testing methods. A number of disease outbreaks have been reported where VBNC bacteria have been implicated as the causative agent. Further molecular and combinatorial research is needed to tackle the threat posed by VBNC bacteria with regard to public health and food safety. Md. Fakruddin, Khanjada Shahnewaj Bin Mannan, and Stewart Andrews Copyright © 2013 Md. Fakruddin et al. All rights reserved. The Effect of Gold and Iron-Oxide Nanoparticles on Biofilm-Forming Pathogens Wed, 25 Sep 2013 14:27:03 +0000 Microbial biofilms on biomaterial implants or devices are hard to eliminate by antibiotics due to their protection by exopolymeric substances that embed the organisms in a matrix, impenetrable for most antibiotics and immune-cells. Application of metals in their nanoparticulated form is currently considered to resolve bacterial infections. Gold and iron-oxide nanoparticles are widely used in different medical applications, but their utilisation to eradicate biofilms on biomaterials implants is novel. Here, we studied the effect of gold and iron oxide nanoparticles on Staphylococcus aureus and Pseudomonas aeruginosa biofilms. We report that biofilm growth was reduced at higher concentrations of gold and iron-oxide nanoparticles compared to absence of nanoparticles. Thus nanoparticles with appropriate concentration could show significant reduction in biofilm formation. Madhu Bala Sathyanarayanan, Reneta Balachandranath, Yuvasri Genji Srinivasulu, Sathish Kumar Kannaiyan, and Guruprakash Subbiahdoss Copyright © 2013 Madhu Bala Sathyanarayanan et al. All rights reserved. Production of a Lipopeptide Biosurfactant by a Novel Bacillus sp. and Its Applicability to Enhanced Oil Recovery Tue, 24 Sep 2013 15:03:59 +0000 Biosurfactants are surface-active compounds derived from varied microbial sources including bacteria and fungi. They are secreted extracellularly and have a wide range of exciting properties for bioremediation purposes. They also have vast applications in the food and medicine industry. With an objective of isolating microorganisms for enhanced oil recovery (EOR) operations, the study involved screening of organisms from an oil-contaminated site. Morphological, biochemical, and 16S rRNA analysis of the most promising candidate revealed it to be Bacillus siamensis, which has been associated with biosurfactant production, for the first time. Initial fermentation studies using mineral salt medium supplemented with crude oil resulted in a maximum biosurfactant yield of 0.64 g/L and reduction of surface tension to 36.1 mN/m at 96 h. Characterization studies were done using thin layer chromatography and Fourier transform infrared spectroscopy. FTIR spectra indicated the presence of carbonyl groups, alkyl bonds, and C–H and N–H stretching vibrations, typical of peptides. The extracted biosurfactant was stable at extreme temperatures, pH, and salinity. Its applicability to EOR was further verified by conducting sand pack column studies that yielded up to 60% oil recovery. Thivaharan Varadavenkatesan and Vytla Ramachandra Murty Copyright © 2013 Thivaharan Varadavenkatesan and Vytla Ramachandra Murty. All rights reserved. 16S rRNA PCR-Denaturing Gradient Gel Electrophoresis of Oral Lactobacillus casei Group and Their Phenotypic Appearances Mon, 23 Sep 2013 15:45:12 +0000 This study aimed to develop a 16S rRNA PCR-denaturing gradient gel electrophoresis (DGGE) to identify the species level of Lactobacillus casei group and to investigate their characteristics of acid production and inhibitory effect. PCR-DGGE has been developed based on the 16S rRNA gene, and a set of HDA-1-GC and HDA-2, designed at V2-V3 region, and another set of CARP-1-GC and CARP-2, designed at V1 region, have been used. The bacterial strains included L. casei ATCC 393, L. paracasei CCUG 32212, L. rhamnosus ATCC 7469, L. zeae CCUG 35515, and 46 clinical strains of L. casei/paracasei/rhamnosus. Inhibitory effect against Streptococcus mutans and acid production were examined. Results revealed that each type species strain and identified clinical isolate showed its own unique DGGE pattern using CARP1-GC and CARP2 primers. HDA1-GC and HDA2 primers could distinguish the strains of L. paracasei from L. casei. It was found that inhibitory effect of L. paracasei was stronger than L. casei and L. rhamnosus. The acid production of L. paracasei was lower than L. casei and L. rhamnosus. In conclusion, the technique has been proven to be able to differentiate between closely related species in L. casei group and thus provide reliable information of their phenotypic appearances. S. Piwat and R. Teanpaisan Copyright © 2013 S. Piwat and R. Teanpaisan. All rights reserved. Admission Screening of Methicillin-Resistant Staphylococcus aureus with Rapid Molecular Detection in Intensive Care Unit: A Three-Year Single-Centre Experience in Hong Kong Thu, 19 Sep 2013 17:26:38 +0000 Background. The admission screening of methicillin-resistant Staphylococcus aureus (MRSA) by rapid molecular assay is considered to be an effective method in reducing the transmission of MRSA in intensive care unit (ICU). Method. The admission screening on patients from ICU once on their admissions by BD GeneOhm MRSA assay has been introduced to Prince of Wales Hospital, Hong Kong, since 2008. The assay was performed on weekdays and reported on the day of testing. Patients pending for results were under standard precautions until the negative screening results were notified, while contact precautions were implemented for MRSA-positive patients. In this study, we compared the MRSA transmission rate in molecular screening periods (2008 to 2010) with the historical culture periods (2006 to 2007) as control. Results. A total of 4679 samples were tested; the average carriage rate of MRSA on admission was 4.45%. By comparing with the historical culture periods, the mean incidence ICU-acquired MRSA infection was reduced from 3.67 to 1.73 per 1000 patient bed days. Conclusion. The implementation of admission screening of MRSA with molecular method in intensive care unit could reduce the MRSA transmission, especially in the area with high MRSA prevalence situation in Hong Kong. Eddie Chi Man Leung, May Kin Ping Lee, and Raymond Wai Man Lai Copyright © 2013 Eddie Chi Man Leung et al. All rights reserved. β-Lactamase-Producing Multidrug-Resistant Bacterial Pathogens from Tracheal Aspirates of Intensive Care Unit Patients at National Institute of Neurological and Allied Sciences, Nepal Mon, 02 Sep 2013 14:48:29 +0000 The widespread use of tracheal intubation and mechanical ventilation to support the critically ill patients increases the risk of development of tracheobronchitis and bronchopneumonia. This cross-sectional study was conducted with an aim to isolate and identify bacterial pathogens from tracheal aspirates producing extended-spectrum β-lactamase (ESBL), AmpC β-lactamase, and metallo-β-lactamase (MBL) from August 2011 to April 2012 at National Institute of Neurological and Allied Sciences (NINAS), Kathmandu, Nepal. ESBL was detected by combined disk assay using cefotaxime and cefotaxime with clavulanate, AmpC β-lactamase by inhibitor-based method using cefoxitin and phenylboronic acid, and MBL by Imipenem-EDTA combined disk method. 167 bacterial strains were isolated from 187 samples and majority of them were Acinetobacter spp. followed by Klebsiella pneumoniae with 32.9% and 25.1%, respectively. 68.8% of isolates were multidrug resistant (MDR) and Acinetobacter spp. constituted 85.4%. ESBL, AmpC β-lactamase, and MBL were detected in 35 (25%), 51 (37.2%), and 11 (36.7%) isolates, respectively. Pseudomonas spp. (42.8%) were the predominant ESBL producer while Acinetobacter spp. were the major AmpC β-lactamase producer (43.1%) and MBL producer (54.5%). Santosh Khanal, Dev Raj Joshi, Dwij Raj Bhatta, Upendra Devkota, and Bharat Mani Pokhrel Copyright © 2013 Santosh Khanal et al. All rights reserved. The Effect of Curcumin and Cotrimoxazole in Salmonella Typhimurium Infection In Vivo Thu, 29 Aug 2013 13:12:52 +0000 Typhoid fever is a disease caused by Salmonella Typhi and commonly treated by an antimicrobial agent such as cotrimoxazole. On the other hand, herbal usage has risen as an adjunctive therapy to treat many diseases. Curcuma (Curcuma domestica) is a commonly used herb which consists of curcumin as its major active compound. Curcumin has been known for its antimicrobial effect, but there is no proof regarding the usage of curcumin and cotrimoxazole together. This research was conducted by using typhoid fever model in mice infected by Salmonella Typhimurium. Each animal was treated with curcumin, cotrimoxazole, or both. Ileum, spleen, and liver of each animal were isolated and cultured. We found that curcumin-cotrimoxazole combination therapy lowered the antimicrobial effectivity of cotrimoxazole in both intraintestinal and extraintestinal organs. We conclude that curcumin-cotrimoxazole combination therapy in typhoid fever has to be reconsidered. Siwipeni Irmawanti Rahayu, Nurdiana Nurdiana, and Sanarto Santoso Copyright © 2013 Siwipeni Irmawanti Rahayu et al. All rights reserved. Role of Flies as Vectors of Foodborne Pathogens in Rural Areas Sun, 04 Aug 2013 14:05:33 +0000 This study aims to evaluate flies as a vector for foodborne pathogens. For this purpose, several flies were collected from different sites from rural areas. These flies were then analyzed for the presence of Enterobacteriaceae, Escherichia coli, Staphylococcus coagulase positive, and Listeria monocytogenes. Another aim of this study was to evaluate some virulence factors of the collected pathogens: susceptibility to some antibiotics and the presence of enterotoxigenic S. aureus. The results showed that flies in the presence of animals demonstrated a significantly higher prevalence of the studied pathogens than those collected in the kitchens, and kitchens situated in the closest proximity to the animal husbandry had a higher count than the kitchens in private houses. Enterobacteriaceae was the indicator organism with the highest microbial counts followed by E. coli and S. aureus. Listeria monocytogenes was not detected from any of the collected flies. The antimicrobial susceptibility test showed that the bacteria carried by the flies possessed multiantibiotic resistance profiles, and enterotoxin A was produced by 17.9% of the confirmed S. aureus isolates. These results demonstrate that flies can transmit foodborne pathogens and their associated toxin and resistance and the areas of higher risk are those in closer proximity to animal production sites. Cláudia Barreiro, Helena Albano, Joana Silva, and Paula Teixeira Copyright © 2013 Cláudia Barreiro et al. All rights reserved. Host-Microbe Interactions in Caenorhabditis elegans Thu, 01 Aug 2013 08:57:37 +0000 A good understanding of how microbes interact with hosts has a direct bearing on our capability of fighting infectious microbial pathogens and making good use of beneficial ones. Among the model organisms used to study reciprocal actions among microbes and hosts, C. elegans may be the most advantageous in the context of its unique attributes such as the short life cycle, easiness of laboratory maintenance, and the availability of different genetic mutants. This review summarizes the recent advances in understanding host-microbe interactions in C. elegans. Although these investigations have greatly enhanced our understanding of C. elegans-microbe relationships, all but one of them involve only one or few microbial species. We argue here that more research is needed for exploring the evolution and establishment of a complex microbial community in the worm’s intestine and its interaction with the host. Rui Zhang and Aixin Hou Copyright © 2013 Rui Zhang and Aixin Hou. All rights reserved. Biodegradation of Polyethoxylated Nonylphenols Wed, 10 Jul 2013 11:12:45 +0000 Polyethoxylated nonylphenols, with different ethoxylation degrees (), are incorporated into many commercial and industrial products such as detergents, domestic disinfectants, emulsifiers, cosmetics, and pesticides. However, the toxic effects exerted by their degradation products, which are persistent in natural environments, have been demonstrated in several animal and invertebrate aquatic species. Therefore, it seems appropriate to look for indigenous bacteria capable of degrading native and its derivatives. In this paper, the isolation of five bacterial strains, capable of using , as unique carbon source, is described. The most efficient degrader bacterial strains were identified as Pseudomonas fluorescens (strain Yas2) and Klebsiella pneumoniae (strain Yas1). Maximal growth rates were reached at pH 8, 27°C in a 5% medium. The degradation extension, followed by viscometry assays, reached 65% after 54.5 h and 134 h incubation times, while the COD values decreased by 95% and 85% after 24 h for the Yas1 and Yas2 systems, respectively. The BOD was reduced by 99% and 99.9% levels in 24 h and 48 h incubations. The viscosity data indicated that the biodegradation by Yas2 follows first-order kinetics. Kinetic rate constant () and half life time () for this biotransformation were estimated to be 0.0072 h−1 and 96.3 h, respectively. Yassellis Ruiz, Luis Medina, Margarita Borusiak, Nairalith Ramos, Gilberto Pinto, and Oscar Valbuena Copyright © 2013 Yassellis Ruiz et al. All rights reserved. Degradation of []MC-LR by a Microcystin Degrading Bacterium Isolated from Lake Rotoiti, New Zealand Thu, 27 Jun 2013 13:46:23 +0000 For the first time a microcystin-degrading bacterium (NV-3 isolate) has been isolated and characterized from a NZ lake. Cyanobacterial blooms in New Zealand (NZ) waters contain microcystin (MC) hepatotoxins at concentrations which are a risk to animal and human health. Degradation of MCs by naturally occurring bacteria is an attractive bioremediation option for removing MCs from drinking and recreational water sources. The NV-3 isolate was identified by 16S rRNA sequence analysis and found to have 100% nucleotide sequence homology with the Sphingomonas MC-degrading bacterial strain MD-1 from Japan. The NV-3 isolate (concentration of  CFU/mL) at 30°C degraded a mixture of [Dha7]MC-LR and MC-LR (concentration 25 μg/mL) at a maximum rate of 8.33 μg/mL/day. The intermediate by-products of [Dha7]MC-LR degradation were detected and similar to MC-LR degradation by-products. The presence of three genes (mlrA, mlrB, and mlrC), that encode three enzymes involved in the degradation of MC-LR, were identified in the NV-3 isolate. This study confirmed that degradation of [Dha7]MC-LR by the Sphingomonas isolate NV-3 occurred by a similar mechanism previously described for MC-LR by Sphingomonas strain MJ-PV (ACM-3962). This has important implications for potential bioremediation of toxic blooms containing a variety of MCs in NZ waters. Theerasak Somdee, Michelle Thunders, John Ruck, Isabelle Lys, Margaret Allison, and Rachel Page Copyright © 2013 Theerasak Somdee et al. All rights reserved.