title: Outbreak of pneumonia in a long-term care facility: antecedent human parainfluenza virus 1 infection may predispose to bacterial pneumonia.
abstract: OBJECTIVE
  To determine the causes of an outbreak of lobar pneumonia.
  
  
  METHODS
  Matched (1:2) case-control study.
  
  
  METHODS
  A 70-bed chronic care facility for older people.
  
  
  METHODS
  Residents of the facility.
  
  
  RESULTS
  Ten residents developed pneumonia over a 10-day period. Two residents died. One case-patient had Streptococcus pneumoniae bacteremia; another had polymerase chain reaction evidence of S. pneumoniae infection. No other etiologic agent was identified. Only four of 10 case-patients had received routine diagnostic cultures of blood or sputum before the administration of antibiotics. Symptoms of upper respiratory illness (URI) among residents before the pneumonia outbreak corresponded with elevation of antibodies to human parainfluenza virus 1 (HPIV1). In a matched case-control study, six of 10 case-patients, compared with five of 20 controls, had symptoms of URI during the preceding month (matched odds ratio (MOR) = 4.5, 95% CI = 0.8-33). Nine case-patients had serum available, and five of these had both serologic evidence of recent HPIV1 infection and recent URI, compared with two of 18 controls (MOR = 9.0, 95% CI = 1.2-208). Only three residents had documentation of pneumococcal vaccination.
  
  
  CONCLUSIONS
  Noninfluenza viral infections may play a role in the pathogenesis of some bacterial pneumonias. S. pneumoniae was the cause of at least two pneumonias; lack of preantibiotic cultures may have interfered with isolation of S. pneumoniae in others. Recent HPIV1 infection was epidemiologically linked to subsequently developing pneumonia. Spread of HPIV1 in the facility may have contributed to increased susceptibility to S. pneumoniae and, potentially, to other bacterial pathogens.
authors.affiliation: Epidemic Intelligence Service, Epidemiology Program Office, Centers for Disease Control and Prevention, Public Health Service, United States Department of Health and Human Services, Atlanta, Georgia 30333, USA.
authors.forename: A E
authors.initials: AE
authors.lastname: Fiore
authors.forename: C
authors.initials: C
authors.lastname: Iverson
authors.forename: T
authors.initials: T
authors.lastname: Messmer
authors.forename: D
authors.initials: D
authors.lastname: Erdman
authors.forename: S M
authors.initials: SM
authors.lastname: Lett
authors.forename: D F
authors.initials: DF
authors.lastname: Talkington
authors.forename: L J
authors.initials: LJ
authors.lastname: Anderson
authors.forename: B
authors.initials: B
authors.lastname: Fields
authors.forename: G M
authors.initials: GM
authors.lastname: Carlone
authors.forename: R F
authors.initials: RF
authors.lastname: Breiman
authors.forename: M S
authors.initials: MS
authors.lastname: Cetron
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000914:Antibodies, Viral / Q000302:isolation & purification*; D016022:Case-Control Studies; D004196:Disease Outbreaks; D006801:Humans; D017053:Infection Control; D008134:Long-Term Care; D008404:Massachusetts / Q000453:epidemiology; D009735:Nursing Homes; D010222:Parainfluenza Virus 1, Human / Q000276:immunology; D011008:Pneumococcal Infections / Q000453:epidemiology* / Q000209:etiology; D011018:Pneumonia, Pneumococcal / Q000453:epidemiology* / Q000209:etiology / Q000382:microbiology; D012141:Respiratory Tract Infections / Q000150:complications* / Q000821:virology; D010253:Respirovirus Infections / Q000150:complications*; D013296:Streptococcus pneumoniae / Q000302:isolation & purification
chemical_list: D000914:Antibodies, Viral