PT - JOURNAL ARTICLE AU - A Pillai AU - J L Mitchell AU - S L Hill AU - R A Stockley TI - A case of <em>Haemophilus parainfluenzae</em>pneumonia AID - 10.1136/thorax.55.7.623 DP - 2000 Jul 01 TA - Thorax PG - 623--624 VI - 55 IP - 7 4099 - http://thorax.bmj.com/content/55/7/623.short 4100 - http://thorax.bmj.com/content/55/7/623.full SO - Thorax2000 Jul 01; 55 AB - A 41 year old woman presented with community acquired pneumonia (CAP) which failed to resolve following treatment with amoxycillin and cefaclor prior to referral. Quantitative culture of sputum revealed a pure growth of Haemophilus parainfluenzae and, following antibiotic susceptibility testing of the isolate, ciprofloxacin was prescribed resulting in resolution of the infection. Immunological investigations showed that the patient had a high titre of H parainfluenzae specific IgM. The combination of a pure growth of H parainfluenzae, a response to appropriate antimicrobial therapy, and the presence of a specific antibody response indicated that this organism had a pathogenic role in the patient's pneumonia and should be considered in the differential diagnosis of CAP.