Open Access Research article

Molecular analysis and distribution of multidrug-resistant Enterococcus faecium isolates belonging to clonal complex 17 in a tertiary care center in Mexico City

Sara A Ochoa1, Gerardo Escalona1, Ariadnna Cruz-Córdova1, Leticia B Dávila1, Zeus Saldaña1, Vicenta Cázares-Domímguez1, Carlos A Eslava2, Briceida López-Martínez3, Rigoberto Hernández-Castro4, Guillermo Aquino-Jarquin5 and Juan Xicohtencatl-Cortes1*

Author Affiliations

1 Departamento de Infectología, Laboratorio de Bacteriología Intestinal, Hospital Infantil de México Federico Gómez, México City, DF 06720, México

2 Departamento de Salud Pública, Facultad de Medicina, Universidad Nacional Autónoma de México, Av. Insurgentes Sur s/n., México City, DF 04510, México

3 Departamento Clínico, Hospital Infantil de México Federico Gómez, México City, DF 06720, México

4 Departamento de Ecología de Agentes Patógenos, Hospital General “Dr. Manuel Gea González”, Tlalpan 14080, México

5 Unidad de Investigación en Enfermedades Oncológicas, Hospital Infantil de México Federico Gómez, Dr. Márquez 162, Col. Doctores, Delegación Cuauhtémoc, México City, DF 06720, México

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BMC Microbiology 2013, 13:291  doi:10.1186/1471-2180-13-291

Published: 11 December 2013

Abstract

Background

Enterococcus faecium has recently emerged as a multidrug-resistant nosocomial pathogen involved in outbreaks worldwide. A high rate of resistance to different antibiotics has been associated with virulent clonal complex 17 isolates carrying the esp and hyl genes and the purK1 allele.

Results

Twelve clinical vancomycin-resistant Enterococcus faecium (VREF) isolates were obtained from pediatric patients at the Hospital Infantil de México Federico Gómez (HIMFG). Among these VREF isolates, 58.3% (7/12) were recovered from urine, while 41.7% (5/12) were recovered from the bloodstream. The VREF isolates showed a 100% rate of resistance to ampicillin, amoxicillin-clavulanate, ciprofloxacin, clindamycin, chloramphenicol, streptomycin, gentamicin, rifampicin, erythromycin and teicoplanin. In addition, 16.7% (2/12) of the isolates were resistant to linezolid, and 66.7% (8/12) were resistant to tetracycline and doxycycline. PCR analysis revealed the presence of the vanA gene in all 12 VREF isolates, esp in 83.3% (10/12) of the isolates and hyl in 50% (6/12) of the isolates. Phylogenetic analysis via molecular typing was performed using pulsed-field gel electrophoresis (PFGE) and demonstrated 44% similarity among the VREF isolates. MLST analysis identified four different sequence types (ST412, ST757, ST203 and ST612).

Conclusion

This study provides the first report of multidrug-resistant VREF isolates belonging to clonal complex 17 from a tertiary care center in Mexico City. Multidrug resistance and genetic determinants of virulence confer advantages among VREF in the colonization of their host. Therefore, the prevention and control of the spread of nosocomial infections caused by VREF is crucial for identifying new emergent subclones that could be challenging to treat in subsequent years.

Keywords:
Enterococcus faecium; Multidrug-resistant; Clonal complex; Pulsotypes; Virulence