Isolation of a bacteriophage specific for CS7-expressing strains of enterotoxigenic Escherichia coli.
Enterotoxigenic Escherichia coli (ETEC) is the most common bacterial cause of childhood diarrhoea in Bangladesh. Among the virulence factors of ETEC, toxins and colonization factors (CFs) play a major role in pathogenesis. Unlike Vibrio cholerae, the relationship between ETEC and ETEC-specific phages is poorly understood and the possible role of ETEC phages in the evolution of ETEC strains in the environment is yet to be established. This study was designed specifically to isolate phages that are specific for ETEC virulence factors. Among the 49 phages isolated from 12 different surface water samples, 13 were tested against 211 ETEC strains collected from clinical and environmental sources. One phage, designated IMM-001, showed a significant specificity towards CS7 CF as it attacked all the CS7-expressing ETEC. Electron microscopic analyses showed that the isolated phage possessed an isomeric hexagonal head and a long filamentous tail. An antibody blocking method and phage neutralization assay confirmed that CS7 pilus is required for the phage infection process, indicating the role of CS7 fimbrial protein as a potential receptor for IMM-001. In summary, this study showed the presence of a lytic phage in environmental water that is specific for the CS7 CF of ETEC.
Begum
Y A
YA
International Centre for Diarrhoeal Disease Research, Bangladesh, GPO Box 128, Dhaka 1000, Bangladesh.
Chakraborty
S
S
International Centre for Diarrhoeal Disease Research, Bangladesh, GPO Box 128, Dhaka 1000, Bangladesh.
Chowdhury
A
A
International Centre for Diarrhoeal Disease Research, Bangladesh, GPO Box 128, Dhaka 1000, Bangladesh.
Ghosh
A N
AN
National Institute of Cholera and Enteric Diseases, Kolkata 700 010, India.
Nair
G B
GB
National Institute of Cholera and Enteric Diseases, Kolkata 700 010, India.
Sack
R B
RB
Department of International Health, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
Svennerholm
A-M
AM
Department of Medical Microbiology and Immunology, The Sahlgrenska Academy at Göteborg University, Box 435, S-40530 Göteborg, Sweden.
Qadri
F
F
International Centre for Diarrhoeal Disease Research, Bangladesh, GPO Box 128, Dhaka 1000, Bangladesh.
D003090:Coliphages / Q000254:growth & development* / Q000302:isolation & purification* / Q000648:ultrastructure; D054307:Enterotoxigenic Escherichia coli / Q000302:isolation & purification / Q000378:metabolism* / Q000821:virology*; D004927:Escherichia coli Infections / Q000382:microbiology; D029968:Escherichia coli Proteins / Q000096:biosynthesis*; D036781:Fimbriae Proteins / Q000096:biosynthesis*; D006801:Humans; D046529:Microscopy, Electron, Transmission; D009500:Neutralization Tests; D011991:Receptors, Virus / Q000096:biosynthesis; D014771:Virion / Q000648:ultrastructure; D037521:Virulence Factors / Q000096:biosynthesis*; D014871:Water Microbiology
D029968:Escherichia coli Proteins; D011991:Receptors, Virus; D037521:Virulence Factors; C022924:colonization factor antigens; D036781:Fimbriae Proteins