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Diarrheagenic Pathogens in Polymicrobial Infections | CDC EID

EID Journal Home > Volume 17, Number 4–April 2011

Volume 17, Number 4–April 2011
Diarrheagenic Pathogens in Polymicrobial Infections
Brianna Lindsay,1 T. Ramamurthy,1 Sourav Sen Gupta, Yoshifumi Takeda, Krishnan Rajendran, G. Balakrish Nair, and O. Colin Stine

Author affiliations: University of Maryland Baltimore, Baltimore, Maryland, USA (B. Lindsay, O.C. Stine); and National Institute for Cholera and Enteric Disease, Kolkata, India (T. Ramamurthy, S. Sen Gupta, Y.

Suggested citation for this article

During systematic active surveillance of the causes of diarrhea in patients admitted to the Infectious Diseases and Beliaghata General Hospital in Kolkata, India, we looked for 26 known gastrointestinal pathogens in fecal samples from 2,748 patients. Samples from about one-third (29%) of the patients contained multiple pathogens. Polymicrobial infections frequently contained Vibrio cholerae O1 and rotavirus. When these agents were present, some co-infecting agents were found significantly less often (p = 10–5 to 10–33), some were detected significantly more often (p = 10–5 to 10–26), and others were detected equally as often as when V. cholerae O1 or rotavirus was absent. When data were stratified by patient age and season, many nonrandom associations remained statistically significant. The causes and effects of these nonrandom associations remain unknown.

The estimated worldwide death rate from diarrheal diseases is ≈2.2 million deaths per year (1). Diarrheal infections may be caused by an array of bacterial, viral, or parasitic pathogens. Some cases have 1 single defined cause, others do not have any defined cause, and a substantial number (one third) are caused by multiple pathogens (2). Because each known diarrheal pathogen fulfills Koch's postulates and is capable of being the sole etiologic agent causing disease, multiple pathogens are not essential for causing disease. How additional pathogens cause and contribute to the disease process is unknown. The source of the multiple pathogens in a patient could simply result from multiple pathogens in an urban environment of crowded, impoverished conditions. If the various pathogens occurred independently in cases of disease, then each pathogen in a polymicrobial infection would be expected to occur in proportion to its presence in all patients with severe diarrhea.

In Kolkata, India, a megacity with a population >10 million, many persons live in crowded urban slums. Medical attention is available at the Infectious Disease and Beliaghata General Hospital, which serves the population of Kolkata. To determine the extent of disease caused by various bacterial, viral, and parasitic pathogens of the gastrointestinal tract, the National Institute of Cholera and Enteric Disease is conducting a systematic survey of patients hospitalized for diarrhea at this hospital. Analyses conducted after 2 years of data collection revealed that approximately one-third (29%) of patients had polymicrobial infections (2); an earlier report from that ongoing study indicated that the 3 parasites detected most often (in 73% of patients with polymicrobial infections) were Giardia lamblia, Entamoeba histolytica, and Cryptosporidium spp. (3). We used data from the same ongoing survey to identify gastrointestinal tract pathogens in the feces of patients with severe diarrhea and to examine the relationships between co-infections of Vibro cholerae O1 and rotavirus with other bacterial, viral, and parasitic pathogens.

Diarrheagenic Pathogens in Polymicrobial Infections | CDC EID

Suggested Citation for this Article
Lindsay B, Ramamurthy T, Sen Gupta S, Takeda Y, Rajendran K, Nair GB, et al. Diarrheagenic pathogens in polymicrobial infections. Emerg Infect Dis [serial on the Internet]. 2011 Apr [date cited].

DOI: 10.3201/eid1704.100939

1These authors contributed equally to this article.

Comments to the Authors
Please use the form below to submit correspondence to the authors or contact them at the following address:

O. Colin Stine, 585 Howard Hall, 660 W Redwood St, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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