Low frequency of enterohemorrhagic, enteroinvasive and diffusely adherent Escherichia coli in children under 5 years in rural Mozambique: a case-control study

Abstract

Background Diarrheagenic Escherichia coli (DEC) are among the leading pathogens associated with endemic diarrhea in low income countries. Yet, few epidemiological studies have focused the contribution of enterohemorrhagic E. coli (EHEC), enteroinvasive E. coli (EIEC) and diffusely adherent E. coli (DAEC). Methods We assessed the contribution of EHEC, EIEC and DAEC isolated from stool samples from a case-control study conducted in children aged < 5 years in Southern Mozambique between December 2007 and November 2012. The isolates were screened by conventional PCR targeting stx1 and stx2 (EHEC), ial and ipaH (EIEC), and daaE (DAEC) genes. Results We analyzed 297 samples from cases with less-severe diarrhea (LSD) matched to 297 controls, and 89 samples from cases with moderate-to-severe diarrhea (MSD) matched to 222 controls, collected between November 3, 2011 and November 2, 2012. DEC were more common among LSD cases (2.7%, [8/297] of cases vs. 1.3% [4/297] of controls; p = 0.243]) than in MSD cases (0%, [0/89] of cases vs. 0.4%, [1/222] of controls; p = 1.000). Detailed analysis revealed low frequency of EHEC, DAEC or EIEC and no association with diarrhea in all age strata. Although the low frequency, EIEC was predominant in LSD cases aged 24–59 months (4.1% for cases vs. 0% for controls), followed by DAEC in similar frequency for cases and controls in infants (1.9%) and lastly EHEC from one control. Analysis of a subset of samples from previous period (December 10, 2007 and October 31, 2011) showed high frequency of DEC in controls compared to MSD cases (16.2%, [25/154] vs. 11.9%, [14/118], p = 0.383, respectively). Among these, DAEC predominated, being detected in 7.7% of cases vs. 17.6% of controls aged 24–59 months, followed by EIEC in 7.7% of cases vs. 5.9% of controls for the same age category, although no association was observed. EHEC was detected in one sample from cases and two from controls. Conclusions Our data suggests that although EHEC, DAEC and EIEC are less frequent in endemic diarrhea in rural Mozambique, attention should be given to their transmission dynamics (e.g. the role on sporadic or epidemic diarrhea) considering that the role of asymptomatic individuals as source of dissemination remains unknown.

Circulación de genes de virulencia asociados a Escherichia coli diarrogénica en aguas residuales del Gran Área Metropolitana de Costa Rica

“…Además, Pérez et al (2010) indicaron que, en niños sintomáticos donde se utilizó el ial como marcador de ECEI, la detección fue del 20 %. En otras regiones, como Mozambique, la presencia de ECEI es relativamente baja, entre el 4,8 % y el 7,7 %, en muestras clínicas de niños entre 0 y 59 meses con diarreas leves o moderadas (Garrine et al, 2020), contrariamente, en Polonia la frecuencia del gen ipaH fue de un 25 % en los efluentes de las PTAR (Osińska et al, 2018). Como se aprecia en la tabla 1, ECEI es responsable de la disentería bacilar, al igual que Shigella spp., según los datos estadísticos del país, la frecuencia de ambos patógenos es sumamente baja, por lo general, asociada a brotes específicos (Instituto Costarricense de Investigación y Enseñanza en Nutrición y Salud, 2013; Ministerio de Salud, 2019).…”

Virulence Factors of Enteric Pathogenic Escherichia coli: A Review

“…The interaction between PMNs and Afa/Dr adhesins accelerates PMN-associated apoptosis and decreases the rate of phagocytosis mediated by PMNs. Across the epithelial cells, DAEC strains also induce the expression of MICA, which is potentially responsible for mediating inflammatory bowel disease (IBD) [ 112 , 116 ].…”

Virulence factors of Enteric Pathogenic Escherichia coli: A Review

“…Interaction between PMNs and Afa/Dr adhesins accelerates PMN associated apoptosis and decreases the rate of phagocytosis mediated by PMNs. Across the epithelial cells, DAEC strains also induce the expression of MICA which is potentially responsible for mediating inflammatory bowel disease (IBD) [112,116].…”