Relapsing life threatening community acquired pneumonia due to rare Legionella species responsive to ceftriaxone and aztreonam

Abstract

A 24 year old Saudi housewife was admitted thrice with life threatening community acquired pneumonia. Even though she responded to an initial cocktail of cefriaxone, erythromcin, rifampicin and flucloxacillin during the second admission, she relapsed within four days of discharge when she was on erythromycin only. During the third admission she was put on ceftriaxone and aztreonam and recovered fully without any relapse. Serology results received later showed Legionella IgM titres of more than 1:256 for Legionella micdadei and Legionella bozemanli, and IgG titres of Legionella hackeliae. This case demonstrates relapsing pneumonia due to Legionella micdadei and bozemanii infection, and previous exposure to Legionella hackeliae. Both species, that is, Legionella micdadei and bozemanii, are resistant to erythromycin, but responded very well to a combination of ceftriaxone and aztreonam have not been used previously for the treatment of Legionnaires diseases.