title: Virulence and antibiotic resistance of Enterococcus faecalis clinical isolates recovered from three states of Mexico. Detection of linezolid resistance.
abstract: OBJECTIVE
  The virulence of Enterococcus faecalis is associated with three proteins involved in biofilm production: Ace, Agg, and Esp. Isolates also vary with respect to drug resistance. The present study investigated four characteristics of clinical isolates of E. faecalis recovered from three hospitals in Mexico, including biofilm production, the presence of biofilm-related genes, antibiotic susceptibility, and clonal diversity.
  
  
  METHODS
  We studied 109 clinical isolates. Biofilm formation was investigated using crystal violet and the safranin method with biofilm index correction. The presence of ace, agg, and esp genes was determined by PCR. Susceptibility to antibiotics was determined by the broth microdilution method and clonal relatedness was determined by pulsed-field gel electrophoresis (PFGE).
  
  
  RESULTS
  Using the crystal violet method, 4.6% (5/109) of isolates were high biofilm producers, 48% (52/109) were moderate producers, 20% (39/109) were low producers, and 11% (12/109) were nonproducers. The agg gene was present in 44% (48/109), the ace gene in 39% (43/109), and the esp gene in 33% (36/109). The esp gene was associated with biofilm production (p <0.001), whereas the ace gene correlated with tetracycline resistance (p <0.01). The biofilm index was associated with the presence of both esp plus agg in glucose medium (p = 0.006). Clinical isolates showed high resistance to tetracycline and ciprofloxacin. Also, 2% of isolates were resistant to linezolid and there was no vancomycin resistance. PFGE revealed 109 different restriction patterns.
  
  
  CONCLUSIONS
  The presence of the esp and agg gene was associated with biofilm production, whereas the presence of the ace gene correlated with tetracycline resistance. Overall, a moderate resistance to antibiotics was detected and there was no clonal relatedness among isolates.
authors: Departamento de Microbiología, Facultad de Medicina, Universidad Autónoma de Nuevo León, Monterrey, Mexico.
authors: Perla
authors: P
authors: López-Salas
authors: Jorge
authors: J
authors: Llaca-Díaz
authors: Rayo
authors: R
authors: Morfin-Otero
authors: Juan Carlos
authors: JC
authors: Tinoco
authors: Eduardo
authors: E
authors: Rodriguez-Noriega
authors: Lorena
authors: L
authors: Salcido-Gutierres
authors: Gloria M
authors: GM
authors: González
authors: Soraya
authors: S
authors: Mendoza-Olazarán
authors: Elvira
authors: E
authors: Garza-González
mesh_terms: D000081:Acetamides / Q000494:pharmacology*; D000890:Anti-Infective Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000378:metabolism; D018441:Biofilms / Q000187:drug effects / Q000254:growth & development*; D002352:Carrier Proteins / Q000378:metabolism; D004352:Drug Resistance, Microbial / Q000235:genetics*; D013293:Enterococcus faecalis / Q000187:drug effects* / Q000235:genetics / Q000472:pathogenicity*; D016908:Gram-Positive Bacterial Infections / Q000188:drug therapy / Q000382:microbiology*; D006801:Humans; D000069349:Linezolid; D008565:Membrane Proteins / Q000378:metabolism; D008800:Mexico; D009842:Oligopeptides / Q000378:metabolism; D023303:Oxazolidinones / Q000494:pharmacology*; D014774:Virulence / Q000187:drug effects / Q000235:genetics; D037521:Virulence Factors / Q000235:genetics / Q000378:metabolism
chemical_list: C121675:Ace protein, Enterococcus; D000081:Acetamides; D000890:Anti-Infective Agents; D001426:Bacterial Proteins; D002352:Carrier Proteins; D008565:Membrane Proteins; D009842:Oligopeptides; D023303:Oxazolidinones; D037521:Virulence Factors; C516501:alanyl-glycyl-glycine; C116707:enterococcal surface protein, esp; D000069349:Linezolid
keywords: Biofilm; Enterococcus faecalis; ace; agg; esp