Zong-Yen Wu

Antibacterial and Synergistic Activity of Pentacyclic Triterpenoids Isolated from Alstonia scholaris.

(1) Background: Alstonia scholaris (Apocynaceae) is an important medicinal plant that has been historically used in “Dai” ethnopharmacy to treat infectious diseases in China. Although various pharmacological activities have been reported, the antimicrobial constitutes of A. scholaris have not yet been identified. The objective of this study is to evaluate the antibacterial constitutes from the leaf extract of A. scholaris and to assess the synergistic effects of isolated compounds with antibiotics against bacterial pathogens.; (2) Methods: The chemical constitutes isolated from the leaf extract of A. scholaris were structurally identified by NMR. The antibacterial and synergistic effect of compounds was assessed by calculating the minimal inhibitory concentration (MIC), checkerboard dilution test, and time-kill assay.; (3) Results: Six pentacyclic triterpenoids were structurally identified as (1) lupeol, (2) betulin, (3) 3-hydroxy-11-ursen-28,13-olide, (4) betulinic acid, (5) oleanolic acid and (6) ursolic acid. Both oleanolic and ursolic acid showed antibacterial activity but were limited to Gram-positive bacteria. Ursolic acid showed a synergistic effect with ampicillin and tetracycline against both Bacillus cereus and S. aureus.; (4) Conclusion: These findings reflect that pentacyclic triterpenoids are the antibacterial chemicals in A. scholaris. The ability of ursolic acid to enhance the activity of antibiotics can constitute a valuable group of therapeutic agents in the future.

Antimicrobial resistance to cefotaxime and ertapenem in Enterobacteriaceae: the effects of altering clinical breakpoints

INTRODUCTION The Clinical and Laboratory Standards Institute (CLSI) updated its antimicrobial susceptibility testing interpretation criteria for Enterobacteriaceae. This study assessed the effects of clinical breakpoint changes in the CLSI 2009 to 2012 guidelines on antibiotic susceptibility testing reports. METHODOLOGY In total, 2,076 non-duplicate clinical isolates of Enterobacteriaceae were analyzed. The disk diffusion method was used for susceptibility testing. The CLSI 2009-12 clinical breakpoints were applied to determine susceptibility of cefotaxime and ertapenem. Combined-disk testing was used for phenotypic confirmation of extended-spectrum beta-lactamase (ESBL) production. RESULTS In total, Enterobacteriaceae resistance rates to cefotaxime increased from 13.1% using the CLSI 2009 guidelines to 23.6% with the CLSI 2010-12 guidelines, and the resistance rates to ertapenem were 0.4%, 1.0% and 0.8% with CLSI 2009, 2011 and 2012, respectively. Based on the 2010-12 CLSI criteria, all ESBL-producing Escherichia coli and Klebsiella pneumoniae were resistant to cefotaxime. Marked differences in susceptibility to ertapenem between the 2009 CLSI criteria and 2012-12 CLSI criteria were noted in ESBL-producing K. pneumoniae. CONCLUSIONS Breakpoints changes in the updated CLSI guidelines resulted in higher resistance rates to cefotaxime and ertapenem. In addition, the effects were different in individual Enterobacteriaceae species. As a result, clinicians may opt to use alternative antimicrobial agents. Upon implementation of the newer CLSI guidelines, laboratories should be aware of the possible consequences and closely monitor the effects.

Cobra bite wound infection caused by Shewanella algae

Shewanella wound infections after snake bites are rare. We report the case of a Shewanella algae wound infection associated with a cobra bite in a 27-year-old woman. The isolate was confirmed by sequencing of the 16S ribosomal DNA gene. This case expands the reported spectrum of infection caused by S. algae and raises the possibility that S. algae could be a causative pathogen in wound infections resulting from snake bites.

Complete Genome Sequence of Campylobacter fetus subsp. testudinum Strain Pet-3, Isolated from a Lizard (Hydrosaurus pustulatus)

ABSTRACT The whole-genome sequence for Campylobacter fetus subsp. testudinum, a pathogen isolated from humans and turtles, has been reported recently. We present another completed genome sequence of the C. fetus subsp. testudinum strain pet-3, which was isolated from a lizard in Taiwan, for further genomic comparison study.

Draft genome sequence of carbapenem-resistant Shewanella algae strain AC isolated from small abalone (Haliotis diversicolor)

OBJECTIVES Shewanella algae is an environmental marine bacterium and an emerging opportunistic human pathogen. Moreover, there are increasing reports of strains showing multidrug resistance, particularly carbapenem-resistant isolates. Although S. algae has been found in bivalve shellfish aquaculture, there is very little genome-wide data on resistance determinants in S. algae from shellfish. The aim of this study was to determine the whole genome sequence of carbapenem-resistant S. algae strain AC isolated from small abalone in Taiwan. METHODS Bacterial genomic DNA was sequenced using an Illumina MiSeq platform with 250-bp paired-end reads. De novo genome assembly was performed using Velvet v.1.2.07. The whole genome was annotated and several candidate genes for antimicrobial resistance were identified. RESULTS The genome size was calculated at 4751156bp, with a mean G+C content of 53.09%. A total of 4164 protein-coding sequences, 7 rRNAs, 85 tRNAs and 5 non-coding RNAs were identified. The genome contains genes associated with resistance to β-lactams, trimethoprim, tetracycline, colistin and quinolones. Multiple efflux pump genes were also detected. CONCLUSION Small abalone is a potential source of foodborne drug-resistant S. algae. The genome sequence of carbapenem-resistant S. algae strain AC isolated from small abalone will provide valuable information for further study of the dissemination of resistance genes at the human-animal interface.

Genome characterization of bile-isolated Shewanella algae ACCC

BackgroundShewanella algae has been recognized as an emerging human pathogen. However, not much is known about the mechanism of its pathogenesis and its adaptation to a special niche such as the hepatobiliary tract.ResultsIn this study, we isolated the S. algae ACCC strain from human bile and performed whole genome sequencing. S. algae ACCC consists of a circular 4,743,354-bp chromosome with a GC content of 53.08%, within 4080 protein coding sequences. The genome of strain ACCC contains a number of candidate genes which have been reported to be associated with bile adaption, including htpB, exbBD, wecA, galU, adeFGH and phoPQ regulon.ConclusionsOur results highlight the association of S. algae with a rare disease profile. Further studies are needed to shed light on the evolution of pathogenesis and the niche adaptation of S. algae.

Genome Analysis of Multidrug-resistant Shewanella algae Isolated from Human Soft Tissue Sample

Department of Computer Science and Information Engineering, National Chung Cheng University, Chia-Yi, Taiwan, Department of Energy, Joint Genome Institute, Walnut Creek, CA, United States, Department of Veterinary Medicine, National Chung Hsing University, Taichung, Taiwan, Division of Clinical Toxicology, Department of Emergency Medicine, Taichung Veterans General Hospital, Taichung, Taiwan, 5 School of Medicine, National Defense Medical Center, Taipei, Taiwan, Department of Nursing, Shu-Zen Junior College of Medicine and Management, Kaohsiung City, Taiwan, 7 Rong Hsing Research Center for Translational Medicine, National Chung Hsing University, Taichung, Taiwan, Division of Infectious Diseases, Department of Internal Medicine, Taichung Veterans General Hospital, Taichung, Taiwan

Genome Sequencing and Comparative Analysis of Stenotrophomonas acidaminiphila Reveal Evolutionary Insights Into Sulfamethoxazole Resistance

Stenotrophomonas acidaminiphila is an aerobic, glucose non-fermentative, Gram-negative bacterium that been isolated from various environmental sources, particularly aquatic ecosystems. Although resistance to multiple antimicrobial agents has been reported in S. acidaminiphila, the mechanisms are largely unknown. Here, for the first time, we report the complete genome and antimicrobial resistome analysis of a clinical isolate S. acidaminiphila SUNEO which is resistant to sulfamethoxazole. Comparative analysis among closely related strains identified common and strain-specific genes. In particular, comparison with a sulfamethoxazole-sensitive strain identified a mutation within the sulfonamide-binding site of folP in SUNEO, which may reduce the binding affinity of sulfamethoxazole. Selection pressure analysis indicated folP in SUNEO is under purifying selection, which may be owing to long-term administration of sulfonamide against Stenotrophomonas.

Characteristics and Phylogeny of Shewanella haliotis Isolated from Cultivated Shellfish in Taiwan

Shewanella haliotis is an emerging human pathogen. Many infectious cases were linked to shellfish ingestion or aquatic exposure. Therefore, it is important to study the phylogeny and distribution of S. haliotis in shellfish aquaculture. We investigated the distribution of S. haliotis in cultivated shellfish farming in Taiwan in which S. haliotis was found in the shellfish from all sampling sites. S. haliotis was identified in cultivated shellfish by 16S rRNA gene sequencing, such as abalone (Haliotis diversicolor), clam (Meretrix lusoria), and oyster (Crassostrea gigas). This study highlighted the contamination of S. haliotis in cultivated shellfish and importance of further study regarding the biodiversity and pathogenesis of S. haliotis.

The Pathogenicity of Shewanella algae and Ability to Tolerate a Wide Range of Temperatures and Salinities

Shewanella algae is a rod-shaped Gram-negative marine bacterium frequently found in nonhuman sources such as aquatic ecosystems and has been shown to be the pathogenic agent in various clinical cases due to the ingestion of raw seafood. The results of this study showed that S. algae was present in approximately one in four samples, including water and shellfish samples. Positive reactions (API systems) in S. algae strains were seen for gelatinase (gelatin); however, negative reactions were found for indole production (tryptophan). S. algae is adapted to a wide range of temperatures (4°C, 25°C, 37°C, and 42°C) and salinity. Temperature is a key parameter in the pathogenicity of S. algae as it appears to induce hemolysis at 25°C and 37°C. S. algae exhibits pathogenic characteristics at widely varying temperatures, which suggests that it may have the ability to adapt to climate change.