Role of enteropathogenic Escherichia coli in paediatric diarrhoeas in South India.
BACKGROUND
Enteropathogenic Escherichia coli(EPEC) is a major cause of diarrhoea in children below 5 years of age. Serotyping is classical method for identification of EPEC strains. But serotypic markers are rarely sufficient to reliably identify the strains as Escherichia coli. Introduction of PCR methodology which depends on detection of virulence factors has provided a practical and rapid way of detecting diarrhoeagenic Esch.coli. Multiantibiotic resistant EPEC strains are a common phenomenon with world wide extension. Moreover for the selection of appropriate therapy of dirrhoeas, knowledge of local antimicrobial therapy pattern plays an important role.


OBJECTIVE
To study the role of EPEC in Paediatric diarrhoea by both Serogrouping and Molecular characterisation by PCR and to analyse the antibiotic susceptabililty patterns of EPEC strains in our area.


METHODS
Prospective study of stool samples collected from children with diarrhoea and without diarrhoea who were below 5 years of age was conducted from May to November 2011. Escherichia.coli isolates were identified by Microscopy, Culture and Biochemical reactions. Among the Escherichia coli isolates, EPEC isolates were identified by Serogrouping. Escherichia coli isolates were also subjected to Molecular characterisation by Multiplex PCR assay and those isolates which showed pathogenic genes were futher serotyped. Antibiotic susceptibility pattern of EPEC isolates was determined by CLSI guidelines.


RESULTS
Among the Escherichia coli isolates 36.8% in the diarrhoeal group and none of them from the nondiarrhoeal group were identified as EPEC by serogrouping. 73.3% of the EPEC isolates were below 2 years of age and no much difference in the sex distribution was observed. Mild to moderate dehydration and feccal leuckocytes were seen in 59.9% and 56.6% of isolates respectively. High resistance to Nalidixic acid, Ampicillin, Cotrimoxazole, Ciprofloxacin and Norfloxacin was observed in the diarrhoeal group and resistance to only ampicillin was seen in the nondiarrhoeal group. In the diarrhoeal group 38.8% of Escherichia coli were EAEC and no other diarrhoeagenic Escherichia coli group was found by molecular characterisation. In the nondiarrhoeal Escherichia coli strains, 46.6% showed EAEC genes. EAEC strains in the diarrhoeal group belonged to multiple serotypes, the most common serotype being ONT and in the nondiarrhoeal group, 85.7% were of a single serotype, the most common isolate being O153. Among the Escherichia coli isolates which agglutinated with EPEC polyvalent antisera, 33.3% were positive for Enteroaggregative genes. (Table 1).


CONCLUSIONS
EPEC is still an important pathogen in paediatric diarrhoeas. O serogrouping can still be relied upon for detection of EPEC. Dehydration is one of the clinical features of EPEC diarrhoea. Fluoroquinolones should only be prescribed in children as second line antibiotics. EAEC are present in classical ' O ' serogroups. Serotype O 153 has an increasing potential for asymptomatic carrier state in children below 5 years of age in our area.
Department of Microbiology, Medical Institute of Medical Sciences, Hyderabad, India.
Gandham Pavani
GP
Tilak
Jyothi Lakshmi G
JL
Mudaliar
Andhra Pradesh; Antibiotic Susceptibility; Enteroaggregative Escherchia coli (EAEC).; Enteropathogenic Escherichia coli (EPEC); Molecular characterisation; Serotyping