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[In vitro emergence of ertapenem resistance in Escherichia coli producing extended-spectrum β-lactamase].
Rev Esp Quimioter. 2014 Mar; 27(1):51-5.RE

Abstract

INTRODUCTION

The occurrence of community-associated infections due to extended-spectrum β-lactamase (ESBL)-producing Escherichia coli is increasing worldwide. These organisms are frequently resistant to many of the antimicrobial agents but remain susceptible to carbapenems. We investigated the in vitro emergence of carbapenem resistance in a collection of clinical isolates of ESBL -producing E. coli.

MATERIAL AND METHODS

First and second-step resistant mutants were obtained from E. coli with ESBL. Aliquots of 50 μl containing > 109 CFU were applied to Mueller-Hinton plates containing meropenem, imipenem or ertapenem. MICs for native strains and mutants were determined using the epsilometric test (E-test).

RESULTS

Resistant mutants were not selected with imipenem or meropenem. E. coli growth was observed on ertapenem (0.5 mg/L)-containing plates in 13 of 57 clinical isolates (22.8 %).The ertapenem MIC for these first-step mutants were ≥ 1 mg/L, remaining susceptible to imipenem and meropenem. The first-step mutants were used as native strains. Six second-step resistant mutants were selected with ertapenem. All were fully resistant (CMI ≥ 8 mg/L) to ertapenem, three were resistant to meropenem and one to imipenem. Four second-step resistant mutants were selected with meropenem. All were resistant to ertapenem, meropenem, and two of them were resistant to imipenem.

CONCLUSIONS

Stable resistant mutants were easy to select with ertapenem among ESBL-producing E. coli. Two steps were necessary to select resistant mutants to meropenem or imipenem. The use of ertapenem in high-inoculum infections or in undrained focus of infection should be monitored to reduce the risk on selection of resistance.

Authors+Show Affiliations

Hugo Edgardo Villar, Departamento de Bacteriología Clínica. Laboratorio Hidalgo, Ladislao Martínez 43 B1640EYA Martínez, Buenos Aires, Argentina. hugo.villar@laboratoriohidalgo.com.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

spa

PubMed ID

24676243

Citation

Villar, H E., et al. "[In Vitro Emergence of Ertapenem Resistance in Escherichia Coli Producing Extended-spectrum Β-lactamase]." Revista Espanola De Quimioterapia : Publicacion Oficial De La Sociedad Espanola De Quimioterapia, vol. 27, no. 1, 2014, pp. 51-5.
Villar HE, Jugo MB, Visser M, et al. [In vitro emergence of ertapenem resistance in Escherichia coli producing extended-spectrum β-lactamase]. Rev Esp Quimioter. 2014;27(1):51-5.
Villar, H. E., Jugo, M. B., Visser, M., Hidalgo, M., Hidalgo, G., & Maccallini, G. C. (2014). [In vitro emergence of ertapenem resistance in Escherichia coli producing extended-spectrum β-lactamase]. Revista Espanola De Quimioterapia : Publicacion Oficial De La Sociedad Espanola De Quimioterapia, 27(1), 51-5.
Villar HE, et al. [In Vitro Emergence of Ertapenem Resistance in Escherichia Coli Producing Extended-spectrum Β-lactamase]. Rev Esp Quimioter. 2014;27(1):51-5. PubMed PMID: 24676243.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - [In vitro emergence of ertapenem resistance in Escherichia coli producing extended-spectrum β-lactamase]. AU - Villar,H E, AU - Jugo,M B, AU - Visser,M, AU - Hidalgo,M, AU - Hidalgo,G, AU - Maccallini,G C, PY - 2014/3/29/entrez PY - 2014/3/29/pubmed PY - 2014/12/15/medline SP - 51 EP - 5 JF - Revista espanola de quimioterapia : publicacion oficial de la Sociedad Espanola de Quimioterapia JO - Rev Esp Quimioter VL - 27 IS - 1 N2 - INTRODUCTION: The occurrence of community-associated infections due to extended-spectrum β-lactamase (ESBL)-producing Escherichia coli is increasing worldwide. These organisms are frequently resistant to many of the antimicrobial agents but remain susceptible to carbapenems. We investigated the in vitro emergence of carbapenem resistance in a collection of clinical isolates of ESBL -producing E. coli. MATERIAL AND METHODS: First and second-step resistant mutants were obtained from E. coli with ESBL. Aliquots of 50 μl containing > 109 CFU were applied to Mueller-Hinton plates containing meropenem, imipenem or ertapenem. MICs for native strains and mutants were determined using the epsilometric test (E-test). RESULTS: Resistant mutants were not selected with imipenem or meropenem. E. coli growth was observed on ertapenem (0.5 mg/L)-containing plates in 13 of 57 clinical isolates (22.8 %).The ertapenem MIC for these first-step mutants were ≥ 1 mg/L, remaining susceptible to imipenem and meropenem. The first-step mutants were used as native strains. Six second-step resistant mutants were selected with ertapenem. All were fully resistant (CMI ≥ 8 mg/L) to ertapenem, three were resistant to meropenem and one to imipenem. Four second-step resistant mutants were selected with meropenem. All were resistant to ertapenem, meropenem, and two of them were resistant to imipenem. CONCLUSIONS: Stable resistant mutants were easy to select with ertapenem among ESBL-producing E. coli. Two steps were necessary to select resistant mutants to meropenem or imipenem. The use of ertapenem in high-inoculum infections or in undrained focus of infection should be monitored to reduce the risk on selection of resistance. SN - 1988-9518 UR - https://www.unboundmedicine.com/medline/citation/24676243/[In_vitro_emergence_of_ertapenem_resistance_in_Escherichia_coli_producing_extended_spectrum_β_lactamase]_ L2 - http://seq.es/seq/0214-3429/27/1/villar.pdf DB - PRIME DP - Unbound Medicine ER -