The document discusses Vibrio parahaemolyticus, a gram-negative bacterium responsible for significant food poisoning, particularly in Japan and China. It outlines a study on its prevalence, virulence, and antimicrobial resistance in food samples across 12 Chinese cities, focusing on two virulence genes (tdh and trh) and fluoroquinolone resistance mechanisms. Results indicate a higher proportion of virulent genes in seafood compared to prepared food, raising concerns about the presence of resistant strains in ready-to-eat foods.

1. Natalia Andrea Álvarez Arias
Medical student
Third semester 2020-1

2. Introduction
It is a gram negative halophilic
bacterium found in estuarine, marine
and coastal environments
-Responsible of 20-30% of food poisoning in
japan.
-Leading nationwide cause of foodborne
bacterial poisoning in China
It has 2 virulence hemolysin factors:
Thermostable direct hemolysin (tdh)
and TDH-related hemolysin (trh)
Leading cause of
human foodborne
gastroenteritis in the
united states
Vibrio Parahaemolyticus

3. Fluoroquinolone
resistance
Mutations in target enzymes
(DNA gyrase and topoisomerase
IV), namely quinolone-resistance
determining regions (QRDRs)
Qnr codes a protein that
protects both DNA-girase
and topoisomerase IV.
Mechanism of action
Plasmid-mediated
quinolone resistance
(PMQR)

4. “The aim of this research is to conduct a study on
the prevalence, virulence, and antimicrobial
resistance of V. parahaemolyticus from different
types of food samples in 12 different cities of China”
OBJECTIVE

5. Materiales
y Métodos
Detection of virulence genes tdh and trh
Amplificar un gen,
fragmento de ADN o un
ARN por medio de una
reacción enzimática in-vitro
Fundamento
Se extrajo ADN genómico
para detectar los genes de
virulencia trh y tdh en las
cepas de Vibrio
Parahaemolyticus
¿Para qué?
PCR

6. Antimicrobial susceptibility testing
. Es la mínima cantidad de
antimicrobiano que es
capaz de impedir el
crecimiento de un
microorganismo en unas
condiciones normalizadas.
Fundamento
Susceptibilidad Antimicrobiana
de las cepas de Vibrio
parahaemolyticus a 8 agentes
antimicrobianos
¿Para qué?
Concentración
inhibitoria
mínima
Microdilución en caldo

7. ERIC-PCR (Enterobacterial Repetitive Intergenic Consensus Polymerase
Chain Reaction)
Para determinar la relación
genética de las 8 cepas de
bacterias resistentes a las
fluoroquinolonas.
Fundamento
¿Para qué?

8. Resultados

10. ● Entre más lejos del 100 esten los corchetes menos genéticamente similares
son las cepas

11. AuthorContribution
The pathogenesis of V.
parahaemolyticus is commonly
associated with the two virulence
genes tdh and trh.
(Chen et al., 2018).
The main resistance mechanisms
to fluoroquinolone described in
Enterobacteriaceae are mutations
in the QRDRs and the presence of
PMQR genes (Herrera-León et al.,
2010).
Herrera-León et al.,
2010).
Ampicillin resistance is very common
among V. parahaemolyticus strains
(Elmahdi et al.,
2016; Xie et al.,
2015; Xie et al.,
2016; Xu et al.,
2016)
Discussion

12. Conclusions
Virulent genes are found in
a greater proportion in
seafood than in prepared
food, however, the finding
of a
fluoroquinolone-resistant
strain of parahaemolyticus
in RTE food (V209) sets
alarms because RTE food is
not supossed to be coocked
before eating.
All the eight
fluoroquinolone-resistant
strains had a substitution at
codon 83 of the GyrA, but not
all had a mutation at parC and
none of them had mutations
in GyrB and ParE, which
suggests that the most
important mechanism of
fluoroquinolone resistance is
in GyrA.
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