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


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 bla CTX-M-1 (ten isolates) and bla TEM-52c genes (one isolate). The ISEcp1 (truncated by IS10 in four strains) and orf477 sequences were found upstream and downstream, respectively, of all bla CTX-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.


Clonal Complex Multilocus Sequence Typing IS10 Element Genetic Environment ESBL Gene 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



This study was financed by an Integrated Action of the Spanish Agency of International Collaboration (AECID) of Spain grant and a grant from the Tunisian Ministry of Higher Education and Scientific Research. V. Estepa has a predoctoral fellowship from the University of La Rioja (Spain).

Part of the results of this manuscript have been presented at the 21st ECCMID/27th ICC Joint Congress of the European Society of Clinical Microbiology and Infectious Diseases and the International Society of Chemotherapy, Milan, Italy, 7–10 May 2011.


  1. 1.
    Cantón R, Novais A, Valverde A, Machado E, Peixe L, Baquero F, Coque TM (2008) Prevalence and spread of extended-spectrum beta-lactamase-producing Enterobacteriaceae in Europe. Clin Microbiol Infect 14:144–153PubMedCrossRefGoogle Scholar
  2. 2.
    Briñas L, Moreno MA, Teshager T, Sáenz Y, Porrero MC, Domínguez L, Torres C (2005) Monitoring and characterization of extended-spectrum beta-lactamases in Escherichia coli strains from healthy and sick animals in Spain in 2003. Antimicrob Agents Chemother 49:1262–1264PubMedCrossRefGoogle Scholar
  3. 3.
    Jouini A, Vinué L, Ben Slama K, Sáenz Y, Klibi N, Hammami S, Boudabous A, Torres C (2007) Characterization of CTX-M and SHV extended-spectrum beta-lactamases and associated resistance genes in Escherichia coli strains of food samples in Tunisia. J Antimicrob Chemother 60:1137–1141PubMedCrossRefGoogle Scholar
  4. 4.
    Ben Slama K, Jouini A, Ben Sallem R, Somalo S, Sáenz Y, Estepa V, Boudabous A, Torres C (2010) Prevalence of broad-spectrum cephalosporin-resistant Escherichia coli isolates in food samples in Tunisia, and characterization of integrons and antimicrobial resistance mechanisms implicated. Int J Food Microbiol 137:281–286PubMedCrossRefGoogle Scholar
  5. 5.
    Cortés P, Blanc V, Mora A, Dahbi G, Blanco JE, Blanco M, López C, Andreu A, Navarro F, Alonso MP, Bou G, Blanco J, Llagostera M (2010) Isolation and characterization of potentially pathogenic antimicrobial-resistant Escherichia coli strains from chicken and pig farms in Spain. Appl Environ Microbiol 76:2799–2805PubMedCrossRefGoogle Scholar
  6. 6.
    Leverstein-van Hall MA, Dierikx CM, Cohen Stuart J, Voets GM, van den Munckhof MP, van Essen-Zandbergen A, Platteel T, Fluit AC, van de Sande-Bruinsma N, Scharinga J, Bonten MJ, Mevius DJ; National ESBL surveillance group (2011) Dutch patients, retail chicken meat and poultry share the same ESBL genes, plasmids and strains. Clin Microbiol Infect 17:873–880PubMedCrossRefGoogle Scholar
  7. 7.
    Mamlouk K, Boutiba-Ben Boubaker I, Gautier V, Vimont S, Picard B, Ben Redjeb S, Arlet G (2006) Emergence and outbreaks of CTX-M beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae strains in a Tunisian hospital. J Clin Microbiol 44:4049–4056PubMedCrossRefGoogle Scholar
  8. 8.
    Ben Slama K, Ben Sallem R, Jouini A, Rachid S, Moussa L, Sáenz Y, Estepa V, Somalo S, Boudabous A, Torres C (2011) Diversity of genetic lineages among CTX-M-15 and CTX-M-14 producing Escherichia coli strains in a Tunisian hospital. Curr Microbiol 62:1794–1801PubMedCrossRefGoogle Scholar
  9. 9.
    Réjiba S, Mercuri PS, Power P, Kechrid A (2011) Emergence and dominance of CTX-M-15 extended spectrum beta-lactamase among Escherichia coli isolates from children. Microb Drug Resist 17:135–140PubMedCrossRefGoogle Scholar
  10. 10.
    Ruppé E, Woerther PL, Diop A, Sene AM, Da Costa A, Arlet G, Andremont A, Rouveix B (2009) Carriage of CTX-M-15-producing Escherichia coli isolates among children living in a remote village in Senegal. Antimicrob Agents Chemother 53:3135–3137PubMedCrossRefGoogle Scholar
  11. 11.
    Clinical Laboratory and Standards Institute (CLSI) (2010) Performance standards for antimicrobial susceptibility testing; Twentieth informational supplement. CLSI document M100-S20. CLSI, Wayne, PA, USAGoogle Scholar
  12. 12.
    Tartof SY, Solberg OD, Manges AR, Riley LW (2005) Analysis of a uropathogenic Escherichia coli clonal group by multilocus sequence typing. J Clin Microbiol 43:5860–5864PubMedCrossRefGoogle Scholar
  13. 13.
    Sáenz Y, Briñas L, Domínguez E, Ruiz J, Zarazaga M, Vila J, Torres C (2004) Mechanisms of resistance in multiple-antibiotic-resistant Escherichia coli strains of human, animal, and food origins. Antimicrob Agents Chemother 48:3996–4001PubMedCrossRefGoogle Scholar
  14. 14.
    Clermont O, Bonacorsi S, Bingen E (2000) Rapid and simple determination of the Escherichia coli phylogenetic group. Appl Environ Microbiol 66:4555–4558PubMedCrossRefGoogle Scholar
  15. 15.
    Clermont O, Lavollay M, Vimont S, Deschamps C, Forestier C, Branger C, Denamur E, Arlet G (2008) The CTX-M-15-producing Escherichia coli diffusing clone belongs to a highly virulent B2 phylogenetic subgroup. J Antimicrob Chemother 61:1024–1028PubMedCrossRefGoogle Scholar
  16. 16.
    Blanco M, Alonso MP, Nicolas-Chanoine MH, Dahbi G, Mora A, Blanco JE, López C, Cortés P, Llagostera M, Leflon-Guibout V, Puentes B, Mamani R, Herrera A, Coira MA, García-Garrote F, Pita JM, Blanco J (2009) Molecular epidemiology of Escherichia coli producing extended-spectrum {beta}-lactamases in Lugo (Spain): dissemination of clone O25b:H4-ST131 producing CTX-M-15. J Antimicrob Chemother 63:1135–1141PubMedCrossRefGoogle Scholar
  17. 17.
    Ruiz J, Simon K, Horcajada JP, Velasco M, Barranco M, Roig G, Moreno-Martínez A, Martínez JA, Jiménez de Anta T, Mensa J, Vila J (2002) Differences in virulence factors among clinical isolates of Escherichia coli causing cystitis and pyelonephritis in women and prostatitis in men. J Clin Microbiol 40:4445–4449PubMedCrossRefGoogle Scholar
  18. 18.
    Moubareck C, Daoud Z, Hakimé NI, Hamzé M, Mangeney N, Matta H, Mokhbat JE, Rohban R, Sarkis DK, Doucet-Populaire F (2005) Countrywide spread of community- and hospital-acquired extended-spectrum beta-lactamase (CTX-M-15)-producing Enterobacteriaceae in Lebanon. J Clin Microbiol 43:3309–3313PubMedCrossRefGoogle Scholar
  19. 19.
    Pallecchi L, Bartoloni A, Fiorelli C, Mantella A, Di Maggio T, Gamboa H, Gotuzzo E, Kronvall G, Paradisi F, Rossolini GM (2007) Rapid dissemination and diversity of CTX-M extended-spectrum beta-lactamase genes in commensal Escherichia coli isolates from healthy children from low-resource settings in Latin America. Antimicrob Agents Chemother 51:2720–2725PubMedCrossRefGoogle Scholar
  20. 20.
    Vinué L, Sáenz Y, Martínez S, Somalo S, Moreno MA, Torres C, Zarazaga M (2009) Prevalence and diversity of extended-spectrum beta-lactamases in faecal Escherichia coli isolates from healthy humans in Spain. Clin Microbiol Infect 15:954–957PubMedCrossRefGoogle Scholar
  21. 21.
    Luvsansharav U-O, Hirai I, Niki M, Nakata A, Yoshinaga A, Moriyama T, Yamamoto Y (2011) Prevalence of fecal carriage of extended-spectrum beta-lactamase-producing Enterobacteriaceae among healthy adult people in Japan. J Infect Chemother 17:722–725PubMedCrossRefGoogle Scholar
  22. 22.
    Sasaki T, Hirai I, Niki M, Nakamura T, Komalamisra C, Maipanich W, Kusolsuk T, Sa-Nguankiat S, Pubampen S, Yamamoto Y (2010) High prevalence of CTX-M beta-lactamase-producing Enterobacteriaceae in stool specimens obtained from healthy individuals in Thailand. J Antimicrob Chemother 65:666–668PubMedCrossRefGoogle Scholar
  23. 23.
    Lavollay M, Mamlouk K, Frank T, Akpabie A, Burghoffer B, Ben Redjeb S, Bercion R, Gautier V, Arlet G (2006) Clonal dissemination of a CTX-M-15 beta-lactamase-producing Escherichia coli strain in the Paris area, Tunis, and Bangui. Antimicrob Agents Chemother 50:2433–2438PubMedCrossRefGoogle Scholar
  24. 24.
    Eckert C, Gautier V, Arlet G (2006) DNA sequence analysis of the genetic environment of various bla CTX-M genes. J Antimicrob Chemother 57:14–23PubMedCrossRefGoogle Scholar
  25. 25.
    Costa D, Poeta P, Sáenz Y, Vinué L, Rojo-Bezares B, Jouini A, Zarazaga M, Rodrigues J, Torres C (2006) Detection of Escherichia coli harbouring extended-spectrum beta-lactamases of the CTX-M, TEM and SHV classes in faecal samples of wild animals in Portugal. J Antimicrob Chemother 58:1311–1312PubMedCrossRefGoogle Scholar
  26. 26.
    Cloeckaert A, Praud K, Doublet B, Bertini A, Carattoli A, Butaye P, Imberechts H, Bertrand S, Collard JM, Arlet G, Weill FX (2007) Dissemination of an extended-spectrum-beta-lactamase bla TEM-52 gene-carrying IncI1 plasmid in various Salmonella enterica serovars isolated from poultry and humans in Belgium and France between 2001 and 2005. Antimicrob Agents Chemother 51:1872–1875PubMedCrossRefGoogle Scholar
  27. 27.
    Bartoloni A, Pallecchi L, Fiorelli C, Di Maggio T, Fernández C, Villagran AL, Mantella A, Bartalesi F, Strohmeyer M, Bechini A, Gamboa H, Rodríguez H, Kristiansson C, Kronvall G, Gotuzzo E, Paradisi F, Rossolini GM (2008) Increasing resistance in commensal Escherichia coli, Bolivia and Peru. Emerg Infect Dis 14:338–340PubMedCrossRefGoogle Scholar
  28. 28.
    Leflon-Guibout V, Blanco J, Amaqdouf K, Mora A, Guize L, Nicolas-Chanoine MH (2008) Absence of CTX-M enzymes but high prevalence of clones, including clone ST131, among fecal Escherichia coli isolates from healthy subjects living in the area of Paris, France. J Clin Microbiol 46:3900–3905PubMedCrossRefGoogle Scholar

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

Personalised recommendations