Journal of Microbiology

Volume 54(1); January 2016

Review

MINIREVIEW] Multidrug efflux pumps in Staphylococcus aureus and their clinical implications: Soojin Jang; J. Microbiol. 2016;54(1):1-8. Published online January 5, 2016; DOI: https://doi.org/10.1007/s12275-016-5159-z

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86 Citations

Abstract: Antibiotic resistance is rapidly spreading among bacteria such as Staphylococcus aureus, an opportunistic bacterial pathogen that causes a variety of diseases in humans. For the last two decades, bacterial multidrug efflux pumps have drawn attention due to their potential association with clinical multidrug resistance. Numerous researchers have demonstrated efflux-mediated resistance in vitro and in vivo and found novel multidrug transporters using advanced genomic information about bacteria. This article aims to provide a concise summary of multidrug efflux pumps and their important clinical implications, focusing on recent findings concerning S. aureus efflux pumps.

Research Support, Non-U.S. Gov'ts

Orbilia tianmushanensis sp. nov., a new member of the O. luteorubella group with an unusual asexual morph: Ying Zhang , Yunrun Zhang , Jianyong Dong , Xiaoxia He , Min Qiao , Hans-Otto Baral , Ke-Qin Zhang , Zefen Yu; J. Microbiol. 2016;54(1):9-13. Published online January 5, 2016; DOI: https://doi.org/10.1007/s12275-016-5369-4

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6 Citations

Abstract: A new species of Orbilia related to O. luteorubella is described mainly based on morphological characters of its asexual morph and molecular data. The sexual morph does not significantly differ from O. luteorubella, whereas the asexual morph obtained from its ascospore isolate resembles members of the non-predacious genus Dactylella, because it has fusiform phragmoconidia borne singly at the apex of conidiophores. Phylogenetic analysis showed that this strain clustered with a clade that included available strains of the O. luteorubella aggregate and was distant from all analysed Dactylella species. Within this clade, the new strain fell between species with filiform conidia and those of a Pseudotripoconidium anamorph. By combining morphological and phylogenetic analyses, we conclude that our isolate belongs to a new taxon. Pleomorphism of the new taxon is described and discussed.

Studies on seasonal dynamics of soil-higher fungal communities in Mongolian oak-dominant Gwangneung forest in Korea: Chang Sun Kim , Jong Woo Nam , Jong Won Jo , Sang-Yong Kim , Jae-Gu Han , Min Woo Hyun , Gi-Ho Sung , Sang-Kuk Han; J. Microbiol. 2016;54(1):14-22. Published online January 5, 2016; DOI: https://doi.org/10.1007/s12275-016-5521-1

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13 Citations

Abstract: We surveyed macrofungi biweekly at defined plots from April to December in 2014, in the Mongolian oak-dominant forest, Gwangneung Forest, Pochen-si, Korea, and analyzed a soilhigher fungal diversity during four seasons (represented by April, August, October, and December). Based on morphological observation of collected specimens, the collected macrofungi were classified into 2 phyla 3 classes 7 orders, 14 families, 21 genera, and 33 species (36 specimens). DNA-based community analyses indicated that soil-higher fungi were classified into 2 phyla, 18 classes, 49 orders, 101 families, and 155 genera (83,360 sequence reads), defined herein as 155 genus-level operational taxonomic units (GOTUs). In the present study, we evaluated and discussed the fungal diversity in seasonal dynamics and soil layers based on collected macrofungi and pyrosequencing data while considering environmental parameters (pH, exchangeable K, T-P, NH4+, NO3-, OM, WR, TOC, and T-N). Moreover, principal components analysis (PCA) showed distinct clusters of the GOTU assemblage associated with the seasons.

Research Support, U.S. Gov't, Non-P.H.S.

Synergistic growth in bacteria depends on substrate complexity: Yi-Jie Deng , Shiao Y. Wang; J. Microbiol. 2016;54(1):23-30. Published online January 5, 2016; DOI: https://doi.org/10.1007/s12275-016-5461-9

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72 Citations

Abstract: bacterial synergism, lignocellulose degradation, bacterial activity, enzyme production, microbial interaction

Research Support, Non-U.S. Gov't

Dimethyl sulfoxide reduction by a hyperhermophilic archaeon Thermococcus onnurineus NA1 via a cysteine-cystine redox shuttle: Ae Ran Choi , Min-Sik Kim , Sung Gyun Kang , Hyun Sook Lee; J. Microbiol. 2016;54(1):31-38. Published online January 5, 2016; DOI: https://doi.org/10.1007/s12275-016-5574-1

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6 Citations

Abstract: A variety of microbes grow by respiration with dimethyl sulfoxide (DMSO) as an electron acceptor, and several distinct DMSO respiratory systems, consisting of electron carriers and a terminal DMSO reductase, have been characterized. The heterotrophic growth of a hyperthermophilic archaeon Thermococcus onnurineus NA1 was enhanced by the addition of DMSO, but the archaeon was not capable of reducing DMSO to DMS directly using a DMSO reductase. Instead, the archaeon reduced DMSO via a cysteine-cystine redox shuttle through a mechanism whereby cystine is microbially reduced to cysteine, which is then reoxidized by DMSO reduction. A thioredoxin reductase-protein disulfide oxidoreductase redox couple was identified to have intracellular cystine-reducing activity, permitting recycle of cysteine. This study presents the first example of DMSO reduction via an electron shuttle. Several Thermococcales species also exhibited enhanced growth coupled with DMSO reduction, probably by disposing of excess reducing power rather than conserving energy.

Journal Article

Evaluation of a novel commercial quaternary ammonium compound for eradication of Mycobacteria, HCV and HBV in Egypt: Yasmine Samy Elkholy , Asmaa Sayed Hegab , Dalia Kadry Ismail , Reem Mostafa Hassan; J. Microbiol. 2016;54(1):39-43. Published online January 5, 2016; DOI: https://doi.org/10.1007/s12275-016-5530-0

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5 Citations

Abstract: Endoscopes are a common source of outbreaks of healthcare- associated infections. It is therefore important to identify high-level disinfectants capable of eliminating or killing all vegetative bacteria, mycobacteria, and viruses. Aldehydebased disinfectants are most commonly used in clinical practice but resistance has recently been detected and side effects associated with these disinfectants are well documented. In this study, we evaluated Virusolve+® EDS, a novel quaternary ammonium compound formulation supplied by Amity international, against Mycobacterium bovis (ATCC-27289), hepatitis C virus (HCV)-positive serum and hepatitis B surface antigen-positive serum. We also compared its efficacy against Cidex® (glutaraldehyde 2%), an aldehyde-based disinfectant. M. bovis showed no growth after 10 weeks with either Virusolve+® or Cidex®. Virusolve+® achieved a 104- fold reduction in the initial 106 HCV load under clean conditions (without red blood cells) for 20 min, whereas Cidex® achieved this reduction under clean and dirty conditions (without and with red blood cells, respectively) after both 10 and 20 min. Both Virusolve+® and Cidex® were able to eradicate hepatitis B virus (HBV) infectivity under clean conditions after 10 and 20 min, whereas under dirty conditions they were only able to eradicate virus infectivity after 20 min. Virusolve+® EDS when compared with Cidex® showed equal mycobactericidal activity completely eradicating M. bovis. However, both showed comparable virucidal activity against HBV, which was more effective under clean conditions, emphasizing the importance of the cleaning step in endoscope reprocessing. Cidex® was more effective at eradicating HCV under dirty conditions after a short contact time.

Research Support, Non-U.S. Gov'ts

Mutational inactivation of OprD in carbapenem-resistant Pseudomonas aeruginosa isolates from Korean hospitals: Chi Hyun Kim , Hee Young Kang , Bo Ra Kim , Hyejin Jeon , Yoo Chul Lee , Sang Hwa Lee , Je Chul Lee; J. Microbiol. 2016;54(1):44-49. Published online January 5, 2016; DOI: https://doi.org/10.1007/s12275-016-5562-5

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21 Citations

Abstract: This study investigated the mechanisms underlying the carbapenem resistance of bloodstream isolates of Pseudomonas aeruginosa obtained from two Korean hospitals. Of the 79 P. aeruginosa isolates, 22 and 21 were resistant to imipenem and meropenem, respectively. The 22 imipenem-resistant P. aeruginosa isolates were classified into 7 sequence types (STs) and 13 pulsotypes. Twelve imipenem-resistant isolates from one hospital were found to belong to the international clone ST111. Two imipenem-resistant P. aeruginosa ST235 isolates carried the blaIMP-6 gene, but the remaining 20 isolates did not produce carbapenemases. Mutations in the oprD gene and a related decrease in gene expression were found in 21 and 5 isolates, respectively. However, all imipenemresistant P. aeruginosa isolates showed no significant expression of OprD in the outer membrane as compared with that of carbapenem-susceptible PAO1 strain. Overexpression of genes associated with efflux pumps, including mexB, mexD, mexF, and mexY, was not found in any imipenem-resistant isolate. One imipenem-resistant P. aeruginosa isolate overexpressed the ampC gene. Our results show that the low permeability of drugs due to the mutational inactivation of OprD is primarily responsible for carbapenem resistance in bloodstream isolates of P. aeruginosa from Korean hospitals.

Conditional probability analysis of multidrug resistance in Gram-negative bacilli isolated from tertiary medical institutions in South Korea during 1999–2009: Yong-Hak Kim; J. Microbiol. 2016;54(1):50-56. Published online January 5, 2016; DOI: https://doi.org/10.1007/s12275-016-5579-9

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6 Citations

Abstract: Multidrug resistance of Gram-negative bacilli is a major problem globally. However, little is known about the combined probability of resistance to various antibiotics. In this study, minimum inhibitory concentrations of widely used antibiotics were determined using clinical isolates of Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Acinetobacter baumannii, randomly chosen from strain collections created during 1999–2009 in tertiary medical institutions in Seoul, South Korea. To analyze combined efficacy of antibiotics against a subgroup of isolates, conditional probabilities were determined based on arbitrary, non-independent patterns of antimicrobial susceptibility and resistance. Multidrug resistance, defined as resistance to three or more classes of antibiotics, was observed in the following order: A. baumannii (96%), P. aeruginosa (65%), E. coli (52%), and K. pneumoniae (7%). A. baumannii strains resistant to gentamicin were found to be resistant to a number of antibiotics, except for colistin and polymyxin B. Resistance to gentamicin following exposure to this antibiotic was highly likely to lead to multidrug resistance in all four microbes. This study shows a causal relationship between gentamicin resistance and the prevalence of multidrug resistance in clinical isolates of Gramnegative bacilli in South Korea during 1999–2009 and suggests the importance of prudent use of gentamicin in hospitals.

Retracted Publication

Interferon-mediated antiviral activities of Angelica tenuissima Nakai and its active components: Prasanna Weeratunga , Md Bashir Uddin , Myun Soo Kim , Byeong-Hoon Lee , Tae-Hwan Kim , Ji-Eun Yoon , Jin Yeul Ma , Hongik Kim , Jong-Soo Lee; J. Microbiol. 2016;54(1):57-70. Published online January 5, 2016; DOI: https://doi.org/10.1007/s12275-016-5555-4

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9 Citations

Abstract: Angelica tenuissima Nakai is a widely used commodity in traditional medicine. Nevertheless, no study has been conducted on the antiviral and immune-modulatory properties of an aqueous extract of Angelica tenuissima Nakai. In the present study, we evaluated the antiviral activities and the mechanism of action of an aqueous extract of Angelica tenuissima Nakai both in vitro and in vivo. In vitro, an effective dose of Angelica tenuissima Nakai markedly inhibited the replication of Influenza A virus (PR8), Vesicular stomatitis virus (VSV), Herpes simplex virus (HSV), Coxsackie virus, and Enterovirus (EV-71) on epithelial (HEK293T/HeLa) and immune (RAW264.7) cells. Such inhibition can be described by the induction of the antiviral state in cells by antiviral, IFNrelated gene induction and secretion of IFNs and pro-inflammatory cytokines. In vivo, Angelica tenuissima Nakai treated BALB/c mice displayed higher survivability and lower lung viral titers when challenged with lethal doses of highly pathogenic influenza A subtypes (H1N1, H5N2, H7N3, and H9N2). We also found that Angelica tenuissima Nakai can induce the secretion of IL-6, IFN-λ, and local IgA in bronchoalveolar lavage fluid (BALF) of Angelica tenuissima Nakai treated mice, which correlating with the observed prophylactic effects. In HPLC analysis, we found the presence of several compounds in the aqueous fraction and among them; we evaluated antiviral properties of ferulic acid. Therefore, an extract of Angelica tenuissima Nakai and its components, including ferulic acid, play roles as immunomodulators and may be potential candidates for novel anti-viral/anti-influenza agents.

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