Pseudoepidemic of streptococcal pharyngitis in a hospital pharmacy

• Published in: American journal of infection control Vol. 29; no. 2; pp. 104 - 108
• Main Authors: Karchmer, Tobi B., Anglim, Anne M., Durbin, Lisa J., Farr, Barry M.
• Format: Journal Article
• Language: English
• Published: St. Louis, MO Mosby, Inc 01.04.2001; Mosby
• Subjects: Anti-Bacterial Agents - therapeutic use; Bacterial diseases; Biological and medical sciences; Diagnostic Errors - statistics & numerical data; Disease Outbreaks - statistics & numerical data; Ent and stomatologic bacterial diseases; False Positive Reactions; Hospitals, University; Human bacterial diseases; Humans; Immunoassay - standards; Infection Control - methods; Infectious diseases; Latex Fixation Tests - standards; Medical sciences; Occupational Health; Personnel, Hospital - statistics & numerical data; Pharmacy Service, Hospital - manpower; Pharyngitis - diagnosis; Pharyngitis - epidemiology; Pharyngitis - etiology; Pharyngitis - microbiology; Pharyngitis - prevention & control; Prospective Studies; Sensitivity and Specificity; Streptococcal Infections - diagnosis; Streptococcal Infections - epidemiology; Streptococcal Infections - etiology; Streptococcal Infections - microbiology; Streptococcal Infections - prevention & control; Streptococcus pyogenes; Human; Nosocomial infection; Health staff; Occupational exposure; Hospital pharmacy; Infection; Streptococcaceae; Streptococcal infection; Streptococcus A; Bacteriosis; Bacteria; Micrococcales; ENT disease; Pharynx disease; Hospital; Pharyngitis
• ISSN: 0196-6553; 1527-3296
• DOI: 10.1067/mic.2001.112749

Context:Streptococcus pyogenes has recently re-emerged as a significant pathogen causing disease ranging from pharyngitis to lethal systemic infection. Six hospital pharmacy employees were diagnosed as having streptococcal pharyngitis during 1 week, and antibiotic prophylaxis was requested to halt the outbreak. Objective: Outbreak investigation. Design: Review of initial cases and prospective evaluation of the remaining pharmacy employees and the antigen detection test being used. Setting: Pharmacy and occupational health department of a university hospital. Population: Sixteen employees of the hospital pharmacy and 19 other employees of the hospital. Results: The 6 pharmacy employees who had positive streptococcal antigen detection tests did not have symptoms suggesting streptococcal pharyngitis. Of the 10 remaining pharmacy employees, none had a positive throat culture for S pyogenes. Specificity of the antigen detection test being used was 53% (95% CI, 30%-75%) in prospective evaluation. Conclusions: This was believed to represent a pseudoepidemic because none of the 6 cases had signs or symptoms typical of streptococcal pharyngitis, none of the remaining 10 pharmacy employees had positive throat cultures, and prospective evaluation found low specificity of the antigen detection test. Whereas use of an accurate test in such a low prevalence setting could have resulted in a higher percentage of results being false-positive, the low specificity of the antigen detection test being used also contributed to the pseudoepidemic. (AJIC Am J Infect Control 2001;29:104-8)