Vibrio parahaemolyticus is a marine and estuarine bacterium that has been the leading cause of foodborne outbreaks which leads to a significant threat to human health worldwide. Consumption of seafood contaminated with V. parahaemolyticus causes acute gastroenteritis in individuals. The bacterium poses two main virulence factor including the thermostable direct hemolysin (tdh) which is a pore-forming protein that contributes to the invasiveness of the bacterium in humans and TDH-related hemolysin (trh), which plays a similar role as tdh in the disease pathogenesis. This study aimed to investigate the antimicrobial resistance V. parahaemolyticus strains in shrimps purchased from wetmarkets and supermarkets. The toxR-based PCR assay indicated that a total of 57.8% (185/320) isolates were positive for V. parahaemolyticus. Only 10% (19/185) toxR-positive isolate exhibit the trh gene and none of the isolates were tested positive for tdh. The MAR index was measured for 14 common antimicrobial agents. The results indicated 98% of the isolates were highly susceptible to imipenem, ampicillin sulbactam (96%), chloramphenicol (95%), trimethoprim-sulfamethoxazole (93%), gentamicin (85%), levofloxacin (83%), and tetracycline (82%). The chloramphenicol (catA2) and kanamycin (aphA-3) resistance genes were detected in the resistant V. parahaemolyticus isolates. Our results demonstrate that shrimps are contaminated with V. parahaemolyticus, some of which carry the trh-gene thus being potential to cause food borne illness. The occurrence of multidrug resistance strains in the environment could be an indication of excessive usage of antibiotics in agriculture and aquaculture fields.

A Streptomyces strain, MUM256 was isolated from Tanjung Lumpur mangrove soil in Malaysia. Characterization of the strain showed that it has properties consistent with those of the members of the genus Streptomyces. In order to explore the potential bioactivities, extract of the fermented broth culture of MUM256 was prepared with organic solvent extraction method. DPPH and SOD activity were utilized to examine the antioxidant capacity and the results have revealed the potency of MUM256 in superoxide anion scavenging activity in dose-dependent manner. The cytotoxicity of MUM256 extract was determined using cell viability assay against 8 different panels of human cancer cell lines. Among all the tested cancer cells, HCT116 was the most sensitive toward the extract treatment. At the highest concentration of tested extract, the result showed 2.3-, 2.0-, and 1.8-folds higher inhibitory effect against HCT116, HT29, and Caco-2 respectively when compared to normal cell line. This result has demonstrated that MUM256 extract was selectively cytotoxic toward colon cancer cell lines. In order to determine the constituents responsible for its bioactivities, the extract was then subjected to chemical analysis using GC-MS. The analysis resulted in the identification of chemical constituents including phenolic and pyrrolopyrazine compounds which may responsible for antioxidant and anticancer activities observed. Based on the findings of this study, the presence of bioactive constituents in MUM256 extract could be a potential source for the development of antioxidative and chemopreventive agents.

A novel Streptomyces, strain MUSC 149T was isolated from mangrove soil. A polyphasic approach was used to study the taxonomy of MUSC 149T, which shows a range of phylogenetic and chemotaxonomic properties consistent with those of the members of the genus Streptomyces. The diamino acid of the cell wall peptidoglycan was LL-diaminopimelic acid. The predominant menaquinones were identified as MK9(H8) and MK9(H6). Phylogenetic analysis indicated that closely related strains include Streptomyces rhizophilus NBRC 108885T (99.2% sequence similarity), S. gramineus NBRC 107863T (98.7%) and S. graminisoli NBRC 108883T (98.5%). The DNA–DNA relatedness values between MUSC 149T and closely related type strains ranged from 12.4 ± 3.3% to 27.3 ± 1.9%. The DNA G + C content was determined to be 72.7 mol%. The extract of MUSC 149T exhibited strong antioxidant activity and chemical analysis reported identification of an antioxidant agent, Pyrrolo[1,2-a]pyrazine-1,4-dione, hexahydro-. These data showed that metabolites of MUSC 149T shall be useful as preventive agent against free-radical associated diseases. Based on the polyphasic study of MUSC 149T, the strain merits assignment to a novel species, for which the name S. mangrovisoli sp. nov. is proposed. The type strain is MUSC 149T (=MCCC 1K00699T=DSM 100438T).

Carbapenem resistant Enterobacteriaceae (CRE) pose an urgent risk to global human health. CRE that are non-susceptible to all commercially available antibiotics threaten to return us to the pre-antibiotic era. Using Single Molecule Real Time (SMRT) sequencing we determined the complete genome of a pandrug-resistant Klebsiella pneumoniae isolate, representing the first complete genome sequence of CRE resistant to all commercially available antibiotics. The precise location of acquired antibiotic resistance elements, including mobile elements carrying genes for the OXA-181 carbapenemase, were defined. Intriguingly, we identified three chromosomal copies of an ISEcp1-blaOXA-181 mobile element, one of which has disrupted the mgrB regulatory gene, accounting for resistance to colistin. Our findings provide the first description of pandrug-resistant CRE at the genomic level, and reveal the critical role of mobile resistance elements in accelerating the emergence of resistance to other last resort antibiotics.

Plasmids of incompatibility group A/C (IncA/C) are becoming increasingly prevalent within pathogenic Enterobacteriaceae. They are associated with the dissemination of multiple clinically relevant resistance genes, including bla CMY and bla NDM . Current typing methods for IncA/C plasmids offer limited resolution. In this study, we present the complete sequence of a bla NDM-1 -positive IncA/C plasmid, pMS6198A, isolated from a multidrug-resistant uropathogenic Escherichia coli strain. Hypersaturated transposon mutagenesis, coupled with transposon-directed insertion site sequencing (TraDIS), was employed to identify conserved genetic elements required for replication and maintenance of pMS6198A. Our analysis of TraDIS data identified roles for the replicon, including repA, a toxin-antitoxin system; two putative partitioning genes, parAB; and a putative gene, 053. Construction of mini-IncA/C plasmids and examination of their stability within E. coli confirmed that the region encompassing 053 contributes to the stable maintenance of IncA/C plasmids. Subsequently, the four major maintenance genes (repA, parAB, and 053) were used to construct a new plasmid multilocus sequence typing (PMLST) scheme for IncA/C plasmids. Application of this scheme to a database of 82 IncA/C plasmids identified 11 unique sequence types (STs), with two dominant STs. The majority of bla NDMpositive plasmids examined (15/17; 88%) fall into ST1, suggesting acquisition and subsequent expansion of this bla NDM -containing plasmid lineage. The IncA/C PMLST scheme represents a standardized tool to identify, track, and analyze the dissemination of important IncA/C plasmid lineages, particularly in the context of epidemiological studies.