Type III Secretion Effector VopQ of Vibrio parahaemolyticus Modulates Central Carbon Metabolism in Epithelial Cells.

Vibrio parahaemolyticus is a Gram-negative halophilic pathogen that frequently causes acute gastroenteritis and occasional wound infection. V. parahaemolyticus contains several virulence factors, including type III secretion systems (T3SSs) and thermostable direct hemolysin (TDH). In particular, T3SS1 is a potent cytotoxic inducer, and T3SS2 is essential for causing acute gastroenteritis. Although much is known about manipulation of host signaling transductions by the V. parahaemolyticus effector, little is known about the host metabolomic changes modulated by V. parahaemolyticus To address this knowledge gap, we performed a metabolomic analysis of the epithelial cells during V. parahaemolyticus infection using capillary electrophoresis-time of flight mass spectrometry (CE-TOF/MS). Our results revealed significant metabolomic perturbations upon V. parahaemolyticus infection. Moreover, we identified that T3SS1's VopQ effector was responsible for inducing the significant metabolic changes in the infected cells. The VopQ effector dramatically altered the host cell's glycolytic, tricarboxylic acid cycle (TCA), and amino acid metabolisms. VopQ effector disrupted host cell redox homeostasis by depleting cellular glutathione and subsequently increasing the level of reactive oxygen species (ROS) production.IMPORTANCE The metabolic response of host cells upon infection is pathogen specific, and infection-induced host metabolic reprogramming may have beneficial effects on the proliferation of pathogens. V. parahaemolyticus contains a range of virulence factors to manipulate host signaling pathways and metabolic processes. In this study, we identified that the T3SS1 VopQ effector rewrites host metabolism in conjunction with the inflammation and cell death processes. Understanding how VopQ reprograms host cell metabolism during the infection could help us to identify novel therapeutic strategies to enhance the survival of host cells during V. parahaemolyticus infection.

Potential transmission opportunity of CTX-M-producing Escherichia coli on a large-scale chicken farm in Vietnam.

OBJECTIVES: Extended-spectrum ß-lactamase (ESBL)-producing Escherichia coli have disseminated worldwide. This study investigated blaCTX-M-positive E. coli on a large-scale Vietnamese chicken farm and analysed whether there was any difference in prevalence and molecular characteristics of blaCTX-M-positive E. coli between the farm and the Vietnamese community. METHODS: Faecal samples were collected from 24 human individuals and 38 chickens from the large-scale chicken farm as well as 51 humans and 36 chickens from the community. All samples were collected between June 2013 and June 2014 in Bavi Province in the Red River Delta region of Vietnam. Molecular characterisation of CTX-M-producing E. coli and genetic relatedness among the isolates were evaluated by conventional typing methods. Antimicrobial susceptibility of the isolates was evaluated by the disk diffusion method. RESULTS: The prevalence of blaCTX-M-positive E. coli was 83.3%, 71.1%, 54.9% and 13.9% in farm workers, farm chickens, community individuals and community backyard chickens, respectively. On average, blaCTX-M-positive E. coli isolates from farm chickens were resistant to 8.3 different antibiotics. The average number of detected aminoglycoside-modifying enzyme genes (3.4 genes) and the detection rate of the plasmid-mediated colistin resistance gene mcr-1 (33.3%) were higher in blaCTX-M-positive E. coli isolated from farm chickens compared with other sampling groups. In addition, two types of indistinguishable pulsed-field gel electrophoresis (PFGE) patterns were observed in six blaCTX-M-65-positive E. coli and three blaCTX-M-55-positive E. coli from farm chickens. CONCLUSIONS: These results suggest a more frequent transmission opportunity of blaCTX-M-positive E. coli on the large-scale Vietnamese chicken farm.

Carriage of Escherichia coli Producing CTX-M-Type Extended-Spectrum ß-Lactamase in Healthy Vietnamese Individuals.

Healthy carriage of CTX-M-type extended-spectrum ß-lactamase (ESBL)-producing Escherichia coli was examined by thrice collecting fecal samples from the same 199 healthy Vietnamese subjects every 6 months. Using pulsed-field gel electrophoresis (PFGE), identical PFGE patterns throughout the three samplings were not observed, although prevalence of E. coli in the subjects was around 50% in the three samplings. Our results suggested a short carriage period of the CTX-M-type ESBL-producing E. coli in healthy Vietnamese subjects.