title: Clinical correlates of herpes simplex virus type 1 loads in the lower respiratory tract of critically ill patients.
abstract: BACKGROUND
  The significance of isolation of herpes simplex virus (HSV) type 1 from the lower respiratory tract in critically ill patients on mechanical ventilation is still unclear. In the current study, we used polymerase chain reaction techniques to quantify HSV-1 to further evaluate its role.
  
  
  OBJECTIVE
  The hypothesis was that high loads reflect invasive pulmonary disease related to prolonged mechanical ventilation and increased mortality, as opposed to shedding from the upper respiratory tract, which leads to lower viral loads.
  
  
  METHODS
  We prospectively studied 77 consecutive patients admitted to the intensive care unit and analyzed 136 tracheal aspirates or bronchoalveolar lavage fluids, taken when clinically indicated in the diagnostic workup of fever, radiologic pulmonary infiltrates, progressive respiratory insufficiency or combinations. Samples were cultured for bacteria and yeasts according to routine microbiological methods and HSV-1 loads were determined by real time quantitative PCR. Viral loads were expressed per number of cells recovered.
  
  
  RESULTS
  HSV-1 load was directly related to the simplified acute physiology score II (rs=0.47, P=0.04) when the first specimen taken proved positive for HSV-1. HSV-1 positivity concurred with Candida spp. colonization. Patients with and without a HSV-1 load did not differ with respect to pulmonary and systemic courses and vital outcomes.
  
  
  CONCLUSIONS
  The data suggest that HSV-1 in the lower respiratory tract originates from shedding in the upper respiratory tract in about 30% of critically ill patients, following immune suppression and reactivation, without invasively infecting the lung. No attributable mortality was observed.
authors.affiliation: Department of Intensive Care, VU University Medical Center, Amsterdam, The Netherlands. ev.dejong@vumc.nl
authors.forename: Evelien
authors.initials: E
authors.lastname: Assink-de Jong
authors.forename: A B Johan
authors.initials: AB
authors.lastname: Groeneveld
authors.forename: Annika M
authors.initials: AM
authors.lastname: Pettersson
authors.forename: Alex
authors.initials: A
authors.lastname: Koek
authors.forename: Christina M J E
authors.initials: CM
authors.lastname: Vandenbroucke-Grauls
authors.forename: Albertus
authors.initials: A
authors.lastname: Beishuizen
authors.forename: Alberdina M
authors.initials: AM
authors.lastname: Simoons-Smit
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001419:Bacteria / Q000302:isolation & purification; D002175:Candida / Q000302:isolation & purification; D016638:Critical Illness; D005260:Female; D018259:Herpesvirus 1, Human / Q000302:isolation & purification*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012121:Respiration, Artificial / Q000009:adverse effects; D012141:Respiratory Tract Infections / Q000473:pathology* / Q000821:virology*; D019562:Viral Load; D055815:Young Adult
keywords: Critically ill; Herpes simplex shedding; Immunosuppression; Outcome; Viral pneumonia