Dear Sir:
We agree with Okeke and others1 that undiscovered enteroinvasive Escherichia coli (EIEC), as well as unidentified Shigella infections, may both account for the increased number of cases detected by Lindsay and others.2 However, we emphasize that the relative proportion of the two pathogens detected depends on the ipaH allele that is examined. The allele used by Lindsay and others2 is the same allele that was used by Sahl and others3; this allele resides on the Shigella chromosome and is not present in any EIEC isolates that have been sequenced to date (D. Rasko, unpublished data). We believe, therefore, that at least the majority of the excess detected cases are likely to be caused by Shigella spp.
- 1.↑
Okeke IN, Aboderin AO, Opintan JA, 2016. Enteroinvasive Escherichia coli may account for uncultured Shigella. Am J Trop Med Hyg 94: 480–481.
- 2.↑
Lindsay B, Das SK, Omore R, Farag TH, Nasrin D, Li S, Panchalingam S, Levine MM, Kotloff K, Nataro JP, Magder L, Hungerford L, Faruque AS, Oundo J, Hossain MA, Adeyemi M, Stine OC, 2015. Association between Shigella infection and diarrhea varies based on location and age of children. Am J Trop Med Hyg 93: 918–924.
- 3.↑
Sahl JW, Morris CR, Emberger J, Fraser CM, Ochieng JB, Juma J, Fields B, Breiman RF, Gilmour M, Nataro JP, Rasko DA, 2015. Defining the phylogenomics of Shigella species: a pathway to diagnostics. J Clin Microbiol 53: 951–960.