Letters in Applied Microbiology

Cover image for Vol. 57 Issue 4

October 2013

Volume 57, Issue 4

Pages 259–384

  1. Editor's Choice

    1. Top of page
    2. Editor's Choice
    3. Original Articles
    1. Analysis of the germination kinetics of individual Bacillus subtilis spores treated with hydrogen peroxide or sodium hypochlorite (pages 259–265)

      B. Setlow, J. Yu, Y.-Q. Li and P. Setlow

      Article first published online: 26 JUN 2013 | DOI: 10.1111/lam.12113

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      Significance and Impact of the Study: This work shows that with Bacillus subtilis spore populations in which approximately 95% of individual spores were killed by several oxidizing agents, >95% of the spores in these populations germinated with nutrients, albeit slowly. This is important, as assay of an early germination event, release of dipicolinic acid, has been suggested as a rapid assay for spore viability and would give false-positive readings for the level of the killing of oxidizing agent-treated spore populations. Analysis of the germination kinetics of multiple individual untreated or oxidizing agent-treated spores also provides new information on proteins damaged by oxidizing agent treatment, and at least some of which are in spores' inner membrane.

  2. Original Articles

    1. Top of page
    2. Editor's Choice
    3. Original Articles
    1. Antibacterial activity and synergistic effect between watercress extracts, 2-phenylethyl isothiocyanate and antibiotics against 11 isolates of Escherichia coli from clinical and animal source (pages 266–273)

      E. Freitas, A. Aires, E. Augusto de Santos Rosa and M. José Saavedra

      Article first published online: 20 JUN 2013 | DOI: 10.1111/lam.12105

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      Significance and Impact of the Study: This in vitro study intends to demonstrate the potential use of watercress extracts and 2-phenylethyl isothiocyanate as antimicrobial tools against extended-spectrum β-lactamases-Escherichia coli and to determine their ability to act synergistically with commercial standard antibiotics. We intended to increase the knowledge about different clinical and pharmaceutical approaches to fight against E. coli rather than the traditional use of antibiotics. The results may be useful to those involved in the pharmaceutical, biochemical and microbiology industry and/or academic research in terms of developing alternative control measures and efficient intervention methods.

    2. Production of S-acetoin from diacetyl by Escherichia coli transformant cells that express the diacetyl reductase gene of Paenibacillus polymyxa ZJ-9 (pages 274–281)

      J. Gao, Y.Y. Xu, F.W. Li and G. Ding

      Article first published online: 11 JUN 2013 | DOI: 10.1111/lam.12107

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      Significance and Impact of the Study: This study demonstrated a highly efficient new method to produce S-acetoin with higher than 99·9% optical purity from diacetyl using whole cells of engineered Escherichia coli. It will therefore decrease the production cost of S-acetoin and highlight its application in asymmetric synthesis of highly valuable chiral compounds.

    3. An In Vitro evaluation of disinfection protocols used for needleless connectors of central venous catheters (pages 282–287)

      M.A. Mazher, A. Kallen, J.R. Edwards and R.M. Donlan

      Article first published online: 7 JUN 2013 | DOI: 10.1111/lam.12108

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      Significance and Impact of the Study: A sensitive and repeatable protocol was developed to evaluate antiseptics for disinfecting catheter needleless connectors (NCs). Povidone-iodine (PI) and chlorhexidine gluconate plus isopropanol (CGI) were more effective than isopropanol (IPA) for reducing Staphylococcus epidermidis contamination of NCs. The effectiveness of PI and CGI was reduced on NCs pre-exposed to human serum and prolonged bacterial inoculation. IPA was also less effective against NCs contaminated with Klebsiella pneumoniae.

    4. You have full text access to this OnlineOpen article
      Assignment of serotype to Salmonella enterica isolates obtained from poultry and their environment in southern Brazil (pages 288–294)

      M. Pulido-Landínez, R. Sánchez-Ingunza, J. Guard and V. Pinheiro do Nascimento

      Article first published online: 24 JUN 2013 | DOI: 10.1111/lam.12110

      Significance and Impact of Study: Single nucleotide polymorphisms found in a group of poultry-associated Salmonella isolates from southern Brazil provided evidence of mixtures of serovar group D serotypes on-farm and in single samples from birds. This finding suggests that co-infection and interserotype competition of Salmonella enterica in poultry could impact the incidence of disease in animals or humans. In addition, unique serotypes were identified on-farm that escaped characterization by antibody typing. Application of cost-efficient and highly discriminatory genomic methods for assigning serotype may alter concepts about the epidemiology of Salm. enterica on-farm and in foods.

    5. Production of melanin pigment from Pseudomonas stutzeri isolated from red seaweed Hypnea musciformis (pages 295–302)

      C. Ganesh Kumar, N. Sahu, G. Narender Reddy, R.B.N. Prasad, N. Nagesh and A. Kamal

      Article first published online: 21 JUN 2013 | DOI: 10.1111/lam.12111

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      Significance and Impact of the Study: This investigation reports a marine Pseudomonas stutzeri strain HMGM-7 [MTCC 11712] that produces significant quantities of melanin (6·7 g l−1) in sea-water medium without the supplementation of L-tyrosine. The confirmation of the produced melanin was carried out by various chemical and physical characterization studies. The isolated melanin may find potential application for use in cosmetic and/or pharmaceutical industries.

    6. Antibiotic content of selective culture media for isolation of Capnocytophaga species from oral polymicrobial samples (pages 303–309)

      E. Ehrmann, A. Jolivet-Gougeon, M. Bonnaure-Mallet and T. Fosse

      Article first published online: 20 JUN 2013 | DOI: 10.1111/lam.12112

      Significance and Impact of the Study: Isolation of Capnocytophaga species is important for the proper diagnosis and treatment of the systemic infections they cause and for epidemiological studies of periodontal flora. We showed that in pure culture, a simple blood agar allowed the growth of all Capnocytophaga species. Nonetheless, in oral samples, because of the abundance of commensal competitive flora, selective media with antibiotics are necessary for the recovery of Capnocytophaga species. The demonstrated superiority of VCAT medium made its use essential for the optimal detection of this bacterial genus. This work showed that extreme caution should be exercised when reporting the isolation of Capnocytophaga species from oral polymicrobial samples, because the culture medium is a determining factor.

    7. Purification and characterization of Bacillus thuringiensis vegetative insecticidal toxin protein(s) (pages 310–316)

      G. Osman, A. Assaeedi, Y. Osman, D. El-Ghareeb and R. Alreedy

      Article first published online: 1 JUL 2013 | DOI: 10.1111/lam.12115

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      Significance and Impact of the Study: Insecticidal activity of Bacillus thuringiensis subsp. aegypti was determined, and its vegetative insecticidal protein was subjected to FPLC for protein purification. This work contributes to improve understanding the different toxins secreted during vegetative growth of Bt. Moreover, the N-terminal amino acid sequences of 88-kDa protein was only 92% identical to that of vip3A, and for 44 kDa was 92% identical with Cry35a, suggesting that we might have identified a new genes. Finally, we have proven these proteins to be novel insecticidal agents that may complement the use of known insecticidal proteins derived from Bacillus.

    8. Evaluation of colorimetric loop-mediated isothermal amplification assay for visual detection of Streptococcus agalactiae and Streptococcus iniae in tilapia (pages 317–324)

      R. Suebsing, J. Kampeera, B. Tookdee, B. Withyachumnarnkul, W. Turner and W. Kiatpathomchai

      Article first published online: 26 JUN 2013 | DOI: 10.1111/lam.12114

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      Significance and Impact of Study: The application of colorimetric LAMP with pre-addition of calcein offers simple, rapid and sensitive technique with applicability for small field laboratories. This technique explored the possible vertical transmission mode of Strep. agalactiae and Strep. iniae under natural aquatic environment. It could be such preliminary data provided for the screening broodstock before breeding and/or the specific-pathogen–free production.

    9. Insignificant β-lactamase activity of human serum albumin: no panic to nonmicrobial-based drug resistance (pages 325–329)

      M.T. Rehman, M. Faheem and A.U. Khan

      Article first published online: 3 JUL 2013 | DOI: 10.1111/lam.12116

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      Significance and Impact of the Study: Earlier reports showed that human serum albumin (HSA) possesses β-lactamase activity, owing to its ability to cleave nitrocefin, and thus contributes to antibiotic resistance. Also, its β-lactamase activity is augmented when exposed to pollutants. As nitrocefin is not an antibiotic of clinical use, the conclusion drawn does not represent a true scenario and is misleading. Our results showed that HSA is inefficient in cleaving nitrocefin as compared to a true β-lactamase (CTX-M-15) and is practically inactive on cephalosporin antibiotics even in the presence pollutants. The findings showed that HSA-mediated hydrolysis of β-lactam antibiotics does not contribute to antibiotic resistance.

    10. Strain-specific detection of orally administered canine jejunum-dominated Lactobacillus acidophilus LAB20 in dog faeces by real-time PCR targeted to the novel surface layer protein (pages 330–335)

      Y. Tang and P.E.J. Saris

      Article first published online: 8 JUL 2013 | DOI: 10.1111/lam.12117

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      Significance and Impact of the Study: A real-time PCR method was developed to detect Lactobacillus acidophilus LAB20, a strain that was previously found dominant in canine gastrointestinal (GI) tract. The quantitative detection was based on targeting to variation region of a novel S-layer protein found in LAB20, allowing to specifically enumerate LAB20 from dog faeces. The results showed that the real-time PCR method was sensitive enough to be used in later intervention studies. Interestingly, LAB20 was found to persist in dog GI tract for 6 weeks. Therefore, LAB20 could be a good candidate to study its colonization and potentially utilize as a canine probiotic.

    11. Biochemical characterization of a recombinant pullulanase from Thermococcus kodakarensis KOD1 (pages 336–343)

      T. Han, F. Zeng, Z. Li, L. Liu, M. Wei, Q. Guan, X. Liang, Z. Peng, M. Liu, J. Qin, S. Zhang and B. Jia

      Article first published online: 8 JUL 2013 | DOI: 10.1111/lam.12118

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      Significance and Impact of the Study: Pullulanases have a great potential in industrial applications including the starch industry, the production of maltose syrups and high-purity glucose and fructose. In this study, a pullulanase from hyperthermophilic archaeon Thermococcus kodakarensis KOD1 was successfully expressed in Escherichia coli and the recombinant enzyme can be purified and characterized. The high activity, broad pH range and stability implicate it as a potential enzyme for industrial applications.

    12. Effect of ethanol on growth of Chrysonilia sitophila (‘the red bread mould’) and Hyphopichia burtonii (‘the chalky mould’) in sliced bread (pages 344–349)

      E. Berni and N. Scaramuzza

      Article first published online: 8 JUL 2013 | DOI: 10.1111/lam.12119

      Significance and Impact of the Study: This study shows that ethanol could represent an effective barrier to prevent spoilage of bakery products by associated moulds such as Chrysonilia sitophila and Hyphopichia burtonii, whose growth on packed and sliced bread was inhibited at very low (0·8%) or medium (2·0%) ethanol concentrations, respectively. The results obtained represent a fundamental point of reference for the bakery industries, as they can apply them in the productive practice to avoid spoilage by C. sitophila and H. burtonii on their products.

    13. A one-step multiplex RT-PCR assay for simultaneous detection of four viruses that infect peach (pages 350–355)

      Y. Yu, Z. Zhao, D. Jiang, Z. Wu and S. Li

      Article first published online: 8 JUL 2013 | DOI: 10.1111/lam.12120

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      Significance and Impact of Study: The mRT-PCR assay described in this study was developed for the simultaneous detection of four peach viruses from infected peach samples is reliable and sensitive. In contrast to conventional uniplex RT-PCR, mRT-PCR is more efficient, reducing costs, time and handling when testing large numbers of samples. This rapid and simple method is useful for large-scale surveys of viruses that infect peach.

    14. Candida sake CPA-1 and other biologically based products as potential control strategies to reduce sour rot of grapes (pages 356–361)

      C. Calvo-Garrido, I. Viñas, P. Elmer, J. Usall and N. Teixidó

      Article first published online: 16 JUL 2013 | DOI: 10.1111/lam.12121

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      Significance and Impact of the Study: Studies on sour rot of grapes are scarce in literature, and this is the first work specifically evaluating sour rot in Spanish vineyards. Sour rot control in field conditions through applications of antagonistic micro-organisms is reported for first time in this study, showing elevated severity reductions (40–67% compared with control). As there are no options available for sour rot control in vineyards, results point Candida sake CPA-1 as an interesting control strategy against grape bunch rots.

    15. Evaluation of pathogenic Escherichia coli occurrence in vegetable samples from district bazaars in Istanbul using real-time PCR (pages 362–367)

      H. Özpınar, B. Turan, İ.H. Tekiner, G. Tezmen, İ. Gökçe and Ö. Akıneden

      Article first published online: 19 JUL 2013 | DOI: 10.1111/lam.12122

      Significance and Impact of the Study: We assessed the occurrence of virulent Escherichia (E.) coli and Shiga-toxin–producing E. coli (STEC) virulent populations in the vegetable samples collected from several district bazaars in Istanbul, Turkey. The results indicated that the vegetables from the bazaars had poor microbial quality and represented a potential health risk to customers.

    16. Biodegradation of thiocyanate by a novel strain of Burkholderia phytofirmans from soil contaminated by gold mine tailings (pages 368–372)

      H.P. Vu, A. Mu and J.W. Moreau

      Article first published online: 22 JUL 2013 | DOI: 10.1111/lam.12123

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      Significance and Impact of the Study: This work describes thiocyanate biodegradation by a novel Burkholderia phytofirmans strain isolated from circumneutral pH gold mining-contaminated soils. Previous reports of bacterial thiocyanate degradation have mainly focused on alkaline environments or culturing conditions (pH ≥ 9). Because cyanidation is used globally in gold mining, with thiocyanate as the major contaminant, our results will interest those working on biotechnological approaches to gold mine waste remediation.

    17. Detection of Escherichia coli O157:H7 using immunomagnetic separation and mPCR in Turkish foods of animal origin (pages 373–379)

      N. Ertas, Z. Gonulalan, Y. Yildirim, F. Karadal, S. Abay and S. Al

      Article first published online: 12 AUG 2013 | DOI: 10.1111/lam.12124

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      Significance and Impact of the Study: Escherichia coli (E. coli) O157:H7 is an important human pathogen. Escherichia coli 0157:H7 infections have been associated with consumption of uncooked meat and meat products, as well as unpasteurized dairy products. This study demonstrated that without specific tests for E. coli virulence factors raw meat and raw-milk cheese could pose public health problems to Turkish consumers.

    18. Co-infection of an animal with more than one genotype can occur in anthrax (pages 380–384)

      W. Beyer and P.C.B. Turnbull

      Article first published online: 12 AUG 2013 | DOI: 10.1111/lam.12140

      Significance and Impact of the Study: Multi-locus variable number of tandem repeats analysis (MLVA)-based fingerprinting techniques have been used in many studies worldwide to characterize the occurrence of different genotypes of Bacillus anthracis in outbreaks of wildlife or livestock and to draw conclusions about the source, the possible routes of spread and the temporal and spatial distribution of outbreak strains. Simultaneous isolation of different genotypes from the same host revealed in our study by MLVA highlights the importance of examining more than a single colony from a clinical sample. This conclusion is not specific for MLVA but holds true for every high-resolution method, including full-genome sequencing.

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