Cephalosporin-resistant Escherichia coli among summer camp attendees with salmonellosis.

Guillem Prats,James R Johnson,Beatriz Mirelis,Lluís Salleras,Elisenda Miró,Ferran Navarro,Ángela Domínguez,Teresa Llovet,Neus Camps

doi:10.3201/eid0910.030179

Guillem Prats, James R Johnson + Show 7 more

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https://doi.org/10.3201/eid0910.030179

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Abstract

Investigation of an acute gastroenteritis outbreak involving >100 persons at a summer camp in Girona, Spain, in June 2002 led to the detection of Salmonella and extended-spectrum cephalosporin-resistant Escherichia coli (ESCREC). Stool cultures were performed for 22 symptomatic campers, three asymptomatic food handlers, and 10 healthy household members. Of the 22 campers, 19 had Salmonella enterica, 9 had an ESCREC strain carrying an extended-spectrum β-lactamase, and 2 had a second ESCREC strain carrying a plasmidic cephamycinase. Related ESCREC were detected in two (salmonella-negative) asymptomatic food handlers and in none of the healthy household members. Fecal ESCREC and its β-lactamases and plasmids were extensively characterized. Three of the five ESCREC clones were recovered from multiple hosts. The apparent dissemination of ESCREC suggests a food or water vehicle. The observed distribution of resistance plasmids and β-lactamase genes in several clones indicates a high degree of horizontal transfer. Heightened vigilance and increased efforts must be made to discover the reservoirs and vehicles for community dissemination of ESCREC.

Highlights

Strains of Escherichia coli that produce enzymes capable of degrading extended- spectrum cephalosporins (ESCs), i.e., extended-spectrum β-lactamases (ESBLs), or these drugs plus cephamycins, i.e., plasmidic or hyperproduction of chromosomal cephamycinases have recently emerged as important nosocomial pathogens [1,2]
Epidemiologic Survey The 225 student campers, 10–16 years of age, and 11 teachers were from three schools in three cities, Tarragona (T), El Prat (EP), and Sant Boi (SB)
Our microbiologic evaluation of an outbreak of Salmonella gastroenteritis at a summer camp uncovered the unsuspected dissemination among campers and camp staff of multiple clones of extended-spectrum cephalosporin-resistant Escherichia coli (ESCREC) containing diverse conjugally transferable β-lactamases

Summary

Introduction

Strains of Escherichia coli that produce enzymes capable of degrading extended- spectrum cephalosporins (ESCs), i.e., extended-spectrum β-lactamases (ESBLs), or these drugs plus cephamycins, i.e., plasmidic or hyperproduction of chromosomal cephamycinases have recently emerged as important nosocomial pathogens [1,2] Some of these strains cannot be reliably detected by clinical microbiology laboratories by using conventional susceptibility tests [3], and even when recognized, treating infections caused by these strains can be challenging because therapeutic options are limited. During an investigation of a summer camp-associated salmonellosis outbreak, we observed that stool cultures from nine campers unexpectedly yielded, on cefoperazone-containing medium, colonies resembling enterobacteriaceae, with a uniform mucoid appearance This result suggested the possibility that the same, probably ESC-resistant, enterobacterial strain was present in all these persons, findings consistent with possible foodborne spread. To gain more knowledge of foodborne spread as a potential mechanism of dissemination of resistance genes, we undertook an extensive molecular epidemiologic analysis of these isolates

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