Abstract
Pathogenic Escherichia coli remains important etiological agent of infantile diarrhea in Bangladesh. Previous studies have focused mostly on clinical strains, but very little is known about their presence in aquatic environments. The present study was designed to characterize potentially pathogenic E. coli isolated between November 2001 and December 2003 from aquatic environments of 13 districts of Bangladesh. Serotyping of 96 randomly selected strains revealed O161 to be the predominant serotype (19%), followed by O55 and O44 (12% each), and 11% untypable. Serotype-based pathotyping of the E. coli strains revealed 47%, 30%, and 6% to belong to EPEC, ETEC, and EHEC pathotypes, respectively. The majority of the 160 strains tested were resistant to commonly used antimicrobial agents. Plasmid profiling showed a total of 17 different bands ranging from 1.3 to 40 kb. However, 35% of the strains did not contain any detectable plasmid, implying no correlation between plasmid and drug resistance. Although virulence gene profiling revealed 97 (61%) of the strains to harbor the gene encoding heat-stable enterotoxin (ST), 2 for the gene encoding Shiga toxin (Stx), and none for the gene for heat-labile enterotoxin (LT), serotype-based pathotyping of E. coli was not fully supported by this gene profiling. A dendrogram derived from the PFGE patterns of 22 strains of three predominant serogroups indicated two major clusters, one containing mainly serogroup O55 and the other O8. Three strains of identical PFGE profiles belonging to serogroup O55 were isolated from three distinct areas, which may be of epidemiological significance. Finally, it may be concluded that serotype-based pathotyping may be useful for E. coli strains of clinical origin; however, it is not precise enough for reliably identifying environmental strains as diarrheagenic.
| Original language | English |
|---|---|
| Pages (from-to) | 359-370 |
| Number of pages | 12 |
| Journal | Microbiology and Immunology |
| Volume | 50 |
| Issue number | 5 |
| Publication status | Published - 2006 |
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Keywords
- Environmental E. coli
- Pathotypes
- PFGE
- Serotypes
ASJC Scopus subject areas
- Immunology and Microbiology(all)
- Microbiology (medical)
- Microbiology
Cite this
Phenotypic and molecular characteristics of Escherichia coli isolated from aquatic environment of Bangladesh. / Alam, Munirul; Nur-A-Hasan, [No Value]; Ahsan, Sunjukta; Pazhani, Gururaja Perumal; Tamura, Kazumichi; Ramamurthy, Thadavarayan; Gomes, Donald James; Rahman, Sabita R.; Islam, Atiqul; Akhtar, Fahmina; Shinoda, Sumio; Watanabe, Haruo; Faruque, Shah M.; Nair, Gopinath Balakrish.
In: Microbiology and Immunology, Vol. 50, No. 5, 2006, p. 359-370.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Phenotypic and molecular characteristics of Escherichia coli isolated from aquatic environment of Bangladesh
AU - Alam, Munirul
AU - Nur-A-Hasan, [No Value]
AU - Ahsan, Sunjukta
AU - Pazhani, Gururaja Perumal
AU - Tamura, Kazumichi
AU - Ramamurthy, Thadavarayan
AU - Gomes, Donald James
AU - Rahman, Sabita R.
AU - Islam, Atiqul
AU - Akhtar, Fahmina
AU - Shinoda, Sumio
AU - Watanabe, Haruo
AU - Faruque, Shah M.
AU - Nair, Gopinath Balakrish
PY - 2006
Y1 - 2006
N2 - Pathogenic Escherichia coli remains important etiological agent of infantile diarrhea in Bangladesh. Previous studies have focused mostly on clinical strains, but very little is known about their presence in aquatic environments. The present study was designed to characterize potentially pathogenic E. coli isolated between November 2001 and December 2003 from aquatic environments of 13 districts of Bangladesh. Serotyping of 96 randomly selected strains revealed O161 to be the predominant serotype (19%), followed by O55 and O44 (12% each), and 11% untypable. Serotype-based pathotyping of the E. coli strains revealed 47%, 30%, and 6% to belong to EPEC, ETEC, and EHEC pathotypes, respectively. The majority of the 160 strains tested were resistant to commonly used antimicrobial agents. Plasmid profiling showed a total of 17 different bands ranging from 1.3 to 40 kb. However, 35% of the strains did not contain any detectable plasmid, implying no correlation between plasmid and drug resistance. Although virulence gene profiling revealed 97 (61%) of the strains to harbor the gene encoding heat-stable enterotoxin (ST), 2 for the gene encoding Shiga toxin (Stx), and none for the gene for heat-labile enterotoxin (LT), serotype-based pathotyping of E. coli was not fully supported by this gene profiling. A dendrogram derived from the PFGE patterns of 22 strains of three predominant serogroups indicated two major clusters, one containing mainly serogroup O55 and the other O8. Three strains of identical PFGE profiles belonging to serogroup O55 were isolated from three distinct areas, which may be of epidemiological significance. Finally, it may be concluded that serotype-based pathotyping may be useful for E. coli strains of clinical origin; however, it is not precise enough for reliably identifying environmental strains as diarrheagenic.
AB - Pathogenic Escherichia coli remains important etiological agent of infantile diarrhea in Bangladesh. Previous studies have focused mostly on clinical strains, but very little is known about their presence in aquatic environments. The present study was designed to characterize potentially pathogenic E. coli isolated between November 2001 and December 2003 from aquatic environments of 13 districts of Bangladesh. Serotyping of 96 randomly selected strains revealed O161 to be the predominant serotype (19%), followed by O55 and O44 (12% each), and 11% untypable. Serotype-based pathotyping of the E. coli strains revealed 47%, 30%, and 6% to belong to EPEC, ETEC, and EHEC pathotypes, respectively. The majority of the 160 strains tested were resistant to commonly used antimicrobial agents. Plasmid profiling showed a total of 17 different bands ranging from 1.3 to 40 kb. However, 35% of the strains did not contain any detectable plasmid, implying no correlation between plasmid and drug resistance. Although virulence gene profiling revealed 97 (61%) of the strains to harbor the gene encoding heat-stable enterotoxin (ST), 2 for the gene encoding Shiga toxin (Stx), and none for the gene for heat-labile enterotoxin (LT), serotype-based pathotyping of E. coli was not fully supported by this gene profiling. A dendrogram derived from the PFGE patterns of 22 strains of three predominant serogroups indicated two major clusters, one containing mainly serogroup O55 and the other O8. Three strains of identical PFGE profiles belonging to serogroup O55 were isolated from three distinct areas, which may be of epidemiological significance. Finally, it may be concluded that serotype-based pathotyping may be useful for E. coli strains of clinical origin; however, it is not precise enough for reliably identifying environmental strains as diarrheagenic.
KW - Environmental E. coli
KW - Pathotypes
KW - PFGE
KW - Serotypes
UR - http://www.scopus.com/inward/record.url?scp=33646839252&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33646839252&partnerID=8YFLogxK
M3 - Article
C2 - 16714843
AN - SCOPUS:33646839252
VL - 50
SP - 359
EP - 370
JO - Microbiology and Immunology
JF - Microbiology and Immunology
SN - 0385-5600
IS - 5
ER -