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Molecular detection identified a type six secretion system in C ampylobacter jejuni from various sources but not from human cases
Author(s) -
Siddiqui F.,
Champion O.,
Akram M.,
Studholme D.,
Eqani S.A.M.A.S.,
Wren B.W.,
Titball R.,
Bokhari H.
Publication year - 2015
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1111/jam.12748
Subject(s) - type vi secretion system , campylobacter jejuni , virulence , biology , microbiology and biotechnology , campylobacter , pathogen , multiplex polymerase chain reaction , bacteria , gene , genetics , polymerase chain reaction
Aim To determine the presence of the T6 SS in Campylobacter jejuni from diverse sources. Methods and Results The recently identified type VI secretion system (T6SS) is a bacterial injection machinery that plays a role in virulence, symbiosis, bacterial interactions and environmental stress responses. This system has been recently discovered in the major enteric pathogen Camp. jejuni . In this study, we used multiplex PCR ( mPCR ), based on conserved genetic markers of the T6SS, to screen 366 Pakistani Camp. jejuni isolates from humans, poultry, cattle, wildlife or waste‐water sources. We identified the T6SS in isolates from all of these sources except humans. The overall prevalence of the T6SS among the isolates was 17/366 (4·6%) and the T6SS positive isolates clustered into four different groups. Transcription of the T6SS genes, determined using RT‐PCR, was observed in bacteria cultured at 37 or 42°C but not in 37°C cultures adjusted to pH 3. Conclusions Campylobacter jejuni isolates harbouring T6 SS markers genes were identified in livestock and non‐livestock sources but in this study we did not identify human diarrhoeal isolates which possessed the T6 SS . We demonstrated down‐regulation of T6 SS in an acidic environment. Significance and Impact of the Study This study questions the role of the T6 SS in human diarrhoeal disease. Moreover this study did not identify a clear association of Camp. jejuni isolates harbouring T6 SS with any of the niches tested. Our study highlights the need to establish the role of the T6 SS in environmental survival or virulence.