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Relationship between enterotoxigenic Escherichia coli and diarrhea among children in Buenos Aires
N Binsztein1, M Rivas, L López Moral
1Instituto Nacional de Microbiología Carlos G. Malbran, Buenos Aires, Argentina.
Insights
Enterotoxigenic Escherichia coli (ETEC) caused 10.6% of acute diarrhea cases in children studied. ETEC strains showed high antibiotic resistance and expressed colonization factors, impacting pediatric health.
Area of Science:
- Microbiology
- Pediatric Infectious Diseases
- Bacteriology
Background:
- Enterotoxigenic Escherichia coli (ETEC) is a significant cause of bacterial diarrhea worldwide, particularly in children.
- Understanding the prevalence, virulence factors, and antibiotic resistance patterns of ETEC is crucial for effective treatment and prevention strategies.
Purpose of the Study:
- To determine the incidence of ETEC in children with acute diarrhea in Buenos Aires.
- To characterize the enterotoxin profiles (heat-stable (ST), heat-labile (LT)), colonization factor antigens (CFA), serotypes, and antibiotic sensitivity of ETEC isolates.
Main Methods:
- A case-control study involving 85 children with acute diarrhea and 38 healthy controls, all under four years old and without recent antibiotic use.
- Isolation and identification of E. coli, detection of ST and LT enterotoxins, and characterization of CFA expression, biotypes, serotypes, and antibiotic susceptibility patterns.
Main Results:
- ETEC was identified in 10.6% of children with diarrhea, primarily producing ST (6/9) or both LT and ST (2/9) toxins. Only one LT-producing ETEC was found in controls.
- Over half (55.5%) of ETEC diarrhea cases exhibited CFA (CFA/I or CFA/II). ST-only strains frequently expressed CFA/I (41.7%) or CFA/II (16.7%).
- ETEC isolates demonstrated high rates of multidrug resistance (82.4% resistant to ≥4 antibiotics) compared to toxin-negative E. coli (50%).
Conclusions:
- ETEC is an important cause of acute diarrhea in children in Buenos Aires, associated with specific virulence factors and significant antibiotic resistance.
- The prevalence of certain ETEC serotypes and their correlation with toxin profiles and CFA expression warrant further investigation.
- Findings highlight the need for continued surveillance of ETEC and antibiotic resistance patterns in pediatric populations.
Abstract:
The incidence of enterotoxigenic Escherichia coli (ETEC) has been studied in 85 children with acute diarrhea in patients in the Hospital de Niños Pedro de Elizalde, Buenos Aires, and in 38 healthy children. All of them were up to four years old and none had received antibiotic treatment within 7 days before sampling. ETEC was recovered in 9 out of 85 (10.6%) children with diarrhea. From these positive cases, 6 were associated with heat-stable (ST), 1 with heat-labile (LT) and 2 with both LT and ST enterotoxins. Only one case (2.6%) of LT-producing ETEC was detected in the control group. In 5 out of 9 ETEC diarrhea cases (55.5%) the isolated strains expressed human colonization factor antigens (CFA); four of them were CFA/I and one CFA/II. The characteristics of the CFA, biotype, serotype and antibiotic sensitivity pattern were studied in 23 E. coli isolates from 10 ETEC positive children. Of the 12 ST only strains, 5 (41.7%) expressed CFA/I and 2 (16.7%) CFA/II (CS2 + CS3). One out of 2 LT/ST strains expressed CFA/I. CFAs were not detected in the ETEC-LT nor in the toxin negative E. coli strains. From the ETEC isolated, 82.4% were resistant to 4 or more antibiotics, whereas only 50% of simultaneously isolated toxin-negative E. coli presented this sensitivity pattern. The different ETEC strains belonged to several different serotypes, some of them rarely observed in other countries. None of these serotypes correlated either with the toxin profile or with the sugar fermentation pattern.(ABSTRACT TRUNCATED AT 250 WORDS)