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Liu J, Silapong S, Jeanwattanalert P, Lertsehtakarn P, Bodhidatta L, Swierczewski B, Mason C, McVeigh AL, Savarino SJ, Nshama R, Mduma E, Maro A, Zhang J, Gratz J, Houpt ER. Multiplex real time PCR panels to identify fourteen colonization factors of enterotoxigenic Escherichia coli (ETEC). PLoS One 2017; 12:e0176882. [PMID: 28475640 PMCID: PMC5419558 DOI: 10.1371/journal.pone.0176882] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 04/18/2017] [Indexed: 01/18/2023] Open
Abstract
Enterotoxigenic Escherichia coli (ETEC) is a leading cause of childhood diarrhea in low income countries and in travelers to those areas. Inactivated enterotoxins and colonization factors (CFs) are leading vaccine candidates, therefore it is important to determine the prevailing CF types in different geographic locations and populations. Here we developed real time PCR (qPCR) assays for 14 colonization factors, including the common vaccine targets. These assays, along with three enterotoxin targets (STh, STp, and LT) were formulated into three 5-plex qPCR panels, and validated on 120 ETEC isolates and 74 E. coli colony pools. The overall sensitivity and specificity was 99% (199/202) and 99% (2497/2514), respectively, compared to the CF results obtained with conventional PCR. Amplicon sequencing of discrepant samples revealed that the qPCR was 100% accurate. qPCR panels were also performed on nucleic acid extracted from stool and compared to the results of the ETEC isolates or E. coli colony pools cultured from them. 95% (105/110) of the CF detections in the cultures were confirmed in the stool. Additionally, direct testing of stool yielded 30 more CF detections. Among 74 randomly selected E. coli colony pools with paired stool, at least one CF was detected in 63% (32/51) of the colony pools while at least one CF was detected in 78% (47/60) of the stool samples (P = NS). We conclude that these ETEC CF assays can be used on both cultures and stool samples to facilitate better understanding of CF distribution for ETEC epidemiology and vaccine development.
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Affiliation(s)
- Jie Liu
- Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, Virginia, United States of America
- * E-mail:
| | - Sasikorn Silapong
- Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok, Thailand
| | | | | | - Ladaporn Bodhidatta
- Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok, Thailand
| | - Brett Swierczewski
- Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok, Thailand
| | - Carl Mason
- Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok, Thailand
| | - Annette L. McVeigh
- Infectious Disease Clinical Research Program (IDCRP), Enteric Disease Department, Infectious Disease Directorate, Naval Medical Research Center, Silver Spring, Maryland, United States of America
| | - Stephen J. Savarino
- Infectious Disease Clinical Research Program (IDCRP), Enteric Disease Department, Infectious Disease Directorate, Naval Medical Research Center, Silver Spring, Maryland, United States of America
| | | | - Esto Mduma
- Haydom Global Health Centre, Haydom, Tanzania
| | - Athanasia Maro
- Kilimanjaro Clinical Research Institute, Moshi, Tanzania
| | - Jixian Zhang
- Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, Virginia, United States of America
| | - Jean Gratz
- Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, Virginia, United States of America
| | - Eric R. Houpt
- Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, Virginia, United States of America
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