Endemic clone Escherichia coli harbouring ECP common pillus versus an outbreak clone in a patient from a hospital, Lisbon

Abstract number: P1236

Nunes F., Amores T., Lito L., Melo Cristino J., Jose Salgado M., Santos M., Duarte A.

Objectives: The aim of this study was to compare an endemic Escherichia coli producing CTX-M-15 extended-spectrum b-lactamases (ESBL) with an outbreak clone E. coli producing AmpC b-lactamase, which is maintained during only one month.

Methods: Four Escherichia coli isolates were identified in a period of three years, from an old patient hospitalised twice times at Hospital Santa Maria in Lisboa. The first one collected in August 2001 from urine, two isolates from urine and blood in April 2004 and the fourth isolate was identified from urine one week later. Antibiotic resistance profiles were determined by disc diffusion method, according to Clinical and Laboratory Standards Institute (CLSI) and the b-lactamase genes were identified with specific primers and sequencing. RAPD M13 DNA fingerprint and phylogenetic group was determined in order to obtain genetic profiles. PCR reaction was also performed to detected genes encoding virulence factors, including adhesins of type P (papC), 1 (fimH) and S. fimbriae (sfaS), cytotoxic necrotising factor-1 (cnf-1), siderophore biosynthesis protein (iucC), a-haemolysin (hlyA), uropathogenic specific protein (usp) and also a subunit of ECP common pillus (ecpA).

Results: All three isolates identified from urine in August 2001 and three years later from urine and blood in 12 April 2004 were ESBL producing strains (CTX-M-15), exhibit the M13 fingerprinting profile 1, the most prevalent in this hospital, belonged to the phylogenetic group B2, typically associated with virulence strains, and harbour fimH, iucC and ecpA genes. The fourth isolate, an outbreak strain identified from urine eight days after (20 April 2004), exhibit a distinct genetic profile. This strain harboured a different b-lactamase, the cephalosporinase AmpC, exhibited the M13 fingerprinting profile XY, included in phylogenetic group B1, usually associated with commensal strains and the virulence genes were not detected including the subunit of ECP common pillus (ecpA).

Conclusions: The endemic clone E. coli producing CTX-M-15 was prevalent in Hospital since 2001 until present. ECP common pillus allows the human intestine colonisation and it might confer an evolutionary advantage, contributing to maintenance and higher prevalence of this clone during three years in this patient compared with outbreak clone E. coli producing AmpC b-lactamase, which was detected in four wards, only during one month, in this hospital.

Session Details

Date: 16/05/2009
Time: 00:00-00:00
Session name: 19th European Congress of Clinical Microbiology and Infectious Diseases
Location: Helsinki, Finland, 16 - 19 May 2009
Presentation type:
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