title: Usefulness of real-time PCR assay targeting lipL32 gene for diagnosis of human leptospirosis in Uruguay.
abstract: BACKGROUND
  Assays based on DNA amplification can provide information that contributes to the initial management of patients with leptospirosis. However, these have not been adopted in Uruguay. Our aim was to evaluate the performance of the lipL32 real-time PCR (qPCR) for diagnosis of leptospirosis.
  
  
  METHODS
  We analyzed by microscopic agglutination test (MAT) and lipL32 qPCR serum samples from 183 patients with suspected leptospirosis. To establish the analytical sensitivity of the qPCR, experimentally spiked samples with known amounts of Leptospira interrogans were analyzed.
  
  
  RESULTS
  The analytical sensitivity of the qPCR was 102 leptospires/mL. In 98 patients MAT results were negative meanwhile 85 showed positive reactions, revealing acute infections. Twenty six acute-phase sera of these 85 patients showed a positive signal by qPCR (diagnostic sensitivity 30%). In these patients the average time between onset of symptoms and collection of the first sample was 8 days. In patients with negative results for qPCR and positive MAT results (n=59) the average interval between onset of symptoms and collection of the first sample was 13 days. The qPCR did not yield false positive results.
  
  
  CONCLUSIONS
  The qPCR had a lower diagnostic sensitivity than MAT and a higher cost. However, it allowed to make an early diagnosis in 26 patients. In patients with confirmed acute infections and negative results by qPCR, more than 8 days had elapsed between the onset of the illness and extraction of the first serum sample. Our data support that the qPCR from sera have clinical utility within the first week of illness.
authors: Instituto de Higiene, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay. sabina@higiene.edu.uy.
authors: Sabina
authors: S
authors: González
authors: Juan Pablo
authors: JP
authors: Geymonat
authors: Elba
authors: E
authors: Hernández
authors: Juan Martín
authors: JM
authors: Marqués
authors: Felipe
authors: F
authors: Schelotto
authors: Gustavo
authors: G
authors: Varela
mesh_terms: D000328:Adult; D000372:Agglutination Tests; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics*; D042241:Early Diagnosis; D005260:Female; D006801:Humans; D007921:Leptospira interrogans / Q000235:genetics / Q000302:isolation & purification*; D007922:Leptospirosis / Q000175:diagnosis*; D008074:Lipoproteins / Q000235:genetics*; D008297:Male; D025202:Molecular Diagnostic Techniques / Q000379:methods*; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity; D013997:Time Factors; D014583:Uruguay; D055815:Young Adult
chemical_list: D001425:Bacterial Outer Membrane Proteins; C406589:LipL32 protein, Leptospira; D008074:Lipoproteins