title: Distinctive features between community-acquired pneumonia (CAP) due to Chlamydophila psittaci and CAP due to Legionella pneumophila admitted to the intensive care unit (ICU).
abstract: The spectrum of community-acquired pneumonia (CAP) due to Chlamydophila psittaci ranges from mild, self-limited CAP, to acute respiratory failure. We performed a retrospective study of 13 consecutive patients with CAP due to C. psittaci and 51 patients with legionellosis admitted in one intensive care unit (ICU) (1993-2011). As compared to patients with legionellosis, patients with psittacosis were younger (median age 48 [38-59] vs. 60 [50-71] years, p = 0.007), less frequently smokers (38 vs. 79 %, p < 0.001), with less chronic disease (15 vs. 57 %, p = 0.02), and longer duration of symptoms before admission (median 6 [5-13] vs. 5 [3-7] days, p = 0.038). They presented with lower Simplified Acute Physiology Score II (median 28 [19-38] vs. 39 [28-46], p = 0.04) and less extensive infiltrates on chest X-rays (median 2 [1-3] vs. 3 [3-4] lobes, p = 0.007). Bird exposure was mentioned in 100 % of psittacosis cases, as compared to 5.9 % of legionellosis cases (p < 0.0001). Extrapulmonary manifestations, biological features, and mortality (15.4 vs. 21.6 %, p = 0.62) were similar in both groups. In conclusion, severe psittacosis shares many features with severe legionellosis, including extrapulmonary manifestations, biological features, and outcome. Psittacosis is an important differential diagnosis for legionellosis, especially in cases of bird exposure, younger age, and more limited disease progression over the initial few days.
authors.affiliation: Service de Maladies Infectieuses et de Réanimation Médicale, Hôpital Pontchaillou, 2 rue Henri Le Guilloux, 35033 Rennes, France. arnaud.gacouin@chu-rennes.fr
authors.forename: A
authors.initials: A
authors.lastname: Gacouin
authors.forename: M
authors.initials: M
authors.lastname: Revest
authors.forename: J
authors.initials: J
authors.lastname: Letheulle
authors.forename: P
authors.initials: P
authors.lastname: Fillatre
authors.forename: S
authors.initials: S
authors.lastname: Jouneau
authors.forename: C
authors.initials: C
authors.lastname: Piau
authors.forename: F
authors.initials: F
authors.lastname: Uhel
authors.forename: P
authors.initials: P
authors.lastname: Tattevin
authors.forename: Y
authors.initials: Y
authors.lastname: Le Tulzo
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D023521:Chlamydophila Infections / Q000175:diagnosis* / Q000382:microbiology; D002691:Chlamydophila psittaci / Q000302:isolation & purification* / Q000472:pathogenicity; D017714:Community-Acquired Infections / Q000175:diagnosis / Q000382:microbiology*; D018450:Disease Progression; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D007362:Intensive Care Units; D016952:Legionella pneumophila / Q000302:isolation & purification* / Q000472:pathogenicity; D007877:Legionnaires' Disease / Q000175:diagnosis* / Q000382:microbiology; D008297:Male; D008875:Middle Aged; D016273:Occupational Exposure / Q000009:adverse effects; D018410:Pneumonia, Bacterial / Q000175:diagnosis* / Q000382:microbiology; D011200:Poultry / Q000382:microbiology; D013902:Radiography, Thoracic; D012189:Retrospective Studies; D018805:Sepsis / Q000382:microbiology; D012720:Severity of Illness Index; D013045:Species Specificity; D013997:Time Factors