Hemolysin-Producing Strains among Diarrheagenic Escherichia coli Isolated from Children under 2 Years Old with Diarrheal Disease.

Anca Mare,Adrian Man,Camelia Vintilă,Răzvan Lucian Coșeriu,Felicia Toma,Adrian Cornel Maier,Cristina Nicoleta Ciurea

doi:10.3390/pathogens9121022

Abstract

Even if serotyping based on O antigens is still routinely used by most laboratories for the detection of diarrheagenic Escherichia coli, this method can provide false-positive reactions, due to the high diversity of O antigens. Molecular methods represent a valuable tool that clarifies these situations. In the Bacteriology Laboratory of Mureș County Hospital, between May 2016 and July 2019, 160 diarrheagenic E. coli strains were isolated from children under 2 years old with diarrheic disease. The strains were identified as Shiga toxin-producing E. coli (STEC)/enteropathogenic Escherichia coli (EPEC) via agglutination with polyvalent sera. STEC strains were serotyped using monovalent sera for serogroup O157. Simplex PCR was performed on the strains to determine the presence of the hlyA gene, and, for the positive ones, the hemolytic activity was tested. Antibiotic susceptibility of the identified diarrheagenic E. coli strains was also investigated. STEC strains were the most frequently identified (49.1%), followed by EPEC (40.2%). The hlyA gene was identified in 12 cases, representing 18.2% of the STEC strains. Even if the extended-spectrum β-lactamase (ESBL)-producing strains represented only 10%, a relevant percentage of multidrug-resistant (MDR) strains (24%) was identified.

Highlights

Even, if in industrialized regions, medical settings and health education are available for almost everyone, diarrheal disease is still an important health issue, especially for children
In 2017, a total of 655 samples were processed for the bacterial etiology of the diarrheic syndrome
Even if the etiology of the diarrhea is more likely to be discovered in adults [13], diarrheic agents can be identified in children, especially young ones

Summary

Introduction

If in industrialized regions, medical settings and health education are available for almost everyone, diarrheal disease is still an important health issue, especially for children. Most children under 3 years suffer one or two episodes of diarrhea every year or an annual average of three episodes until 5 years. The etiology is remarkably diverse—viral (rotavirus, norovirus, astrovirus), bacterial (Salmonella spp., Shigella spp., Campylobacter spp., Yersinia spp., diarrheagenic Escherichia coli, Clostridioides difficile), parasitic (Giardia lamblia), or fungal (Cryptosporidium spp., Entamoeba histolytica). From the clinical point of view, the etiology is important, the basic treatment is similar in all cases (rehydration, antidiarrheal medication, and probiotics). Because the antimicrobial treatment is not usually recommended for acute diarrhea in children, it is difficult to decide the etiological diagnosis and when antibiotic treatment is needed [1,2,3,4,5].

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Discussion

Conclusion