European Journal of Clinical Microbiology & Infectious Diseases

, Volume 31, Issue 7, pp 1511–1516

Prevalence and characterisation of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli isolates in healthy volunteers in Tunisia

  • R. Ben Sallem
  • K. Ben Slama
  • V. Estepa
  • A. Jouini
  • H. Gharsa
  • N. Klibi
  • Y. Sáenz
  • F. Ruiz-Larrea
  • A. Boudabous
  • C. Torres
Article

DOI: 10.1007/s10096-011-1471-z

Cite this article as:
Ben Sallem, R., Ben Slama, K., Estepa, V. et al. Eur J Clin Microbiol Infect Dis (2012) 31: 1511. doi:10.1007/s10096-011-1471-z

Abstract

The objective of this investigation was to analyse the carriage rate of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli in faecal samples of healthy humans in Tunisia and to characterise the recovered isolates. One hundred and fifty samples were inoculated on MacConkey agar plates supplemented with cefotaxime (2 μg/ml) for ESBL-positive E. coli recovery. The characterisation of ESBL genes and their genetic environments, detection of associated resistance genes, multilocus sequence typing (MLST) and phylogroup typing were performed by polymerase chain reaction (PCR) and sequencing. The presence and characterisation of integrons and virulence factors were studied by PCR and sequencing. ESBL-positive E. coli isolates were detected in 11 of 150 faecal samples (7.3%) and one isolate/sample was further characterised. These isolates contained the blaCTX-M-1 (ten isolates) and blaTEM-52c genes (one isolate). The ISEcp1 (truncated by IS10 in four strains) and orf477 sequences were found upstream and downstream, respectively, of all blaCTX-M-1 genes. Seven different sequence types (STs) and three phylogroups were identified among CTX-M-1-producing isolates [ST/phylogroup (number of isolates)]: ST58/B1 (3), ST57/D (2), ST165/A (1), ST155/B1 (1), ST10/A (1), ST398/A (1) and ST48/B1 (1). The TEM-52-producing isolate was typed as ST219 and phylogroup B2. Six ESBL isolates contained class 1 integrons with the gene cassettes dfrA17-aadA5 (five isolates) and dfrA1-aadA1 (one). Healthy humans in the studied country could be a reservoir of CTX-M-1-producing E. coli.

Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  • R. Ben Sallem
    • 1
  • K. Ben Slama
    • 1
  • V. Estepa
    • 2
  • A. Jouini
    • 1
  • H. Gharsa
    • 1
  • N. Klibi
    • 1
  • Y. Sáenz
    • 3
  • F. Ruiz-Larrea
    • 2
  • A. Boudabous
    • 1
  • C. Torres
    • 2
    • 3
  1. 1.Laboratoire des Microorganismes et Biomolécules Actives, Faculté des Sciences de TunisUniversité Tunis-El ManarTunisTunisia
  2. 2.Área de Bioquímica y Biología MolecularUniversidad de La RiojaLogroñoSpain
  3. 3.Área de Microbiología MolecularCentro de Investigación Biomédica de La RiojaLogroñoSpain