Opportunistic Pneumonia Caused by a New Acid-fast Bacterium

Abstract

An 80-year-old black woman with a clinical diagnosis of unclassified malignant lymphoproliferative disease experienced acute pneumonia four days after chemotherapy was begun. Open lung biopsy revealed acute suppurative pneumonia with dense neutrophilic alveolar infiltrates but without granulomas or caseous necrosis. Numerous intra- and extracellular gram-negative bacilli were present, some of which were acid-fast. Routine bacterial, fungal, and mycobacterial cultures were negative. The organism was successfully cultivated by embryonated egg inoculation with subsequent transfer to buffered charcoal yeast extract agar. Serologic studies using the indirect fluorescent antibody technic confirmed the presence of an organism recently described as the "Pittsburgh pneumonia agent," further suggesting that this particular organism is a significant cause of suppurative pneumonia in the immunocompromised host.

Acid‐fast‐positive Legionella pneumophila: A possible pitfall in the cytologic diagnosis of mycobacterial infection in pulmonary specimens

“…Legionellae do not stain with hematoxylin-eosin in formalin-fixed paraffin tissue sections but can be demon- strated easily with Dieterle or Warthin-Starry silver impregnation procedures. 11 While original descriptions of the agent of Legionnaires' disease did not include acid fastness as a characteristic, 12 subsequent reports of opportunistic pneumonia likely secondary to Legionellae were reported by Rogers et al 13 and Talamo et al 14 In both series of patients, the infected individuals were severely ill, immunocompromised patients (four were renal-transplant patients), similar to the case presented in this report.…”

“…Similar observations were reported by Schwebke et al 9 Most L. micdadei, when visualized in clinical specimens, are acid-fast when stained by a modified Ziehl-Neelsen, Kinyoun, or Fite Stain. 13,14,16,17 Those authors concluded that L. micdadei should be considered and included in the empiric coverage when the acid-fast smear is positive, pending confirmation by specific fluorescent stains.…”

Detection of infection or infectious agents by use of cytologic and histologic stains

“…are weakly acid fast, so that culture is critical for diagnosis. Legionella micdadei also appears acid fast in tissue, a characteristic most frequently demonstrated with Kinyoun and Fite stains and less often with Ziehl-Neelsen stain (133,152,170,196). For detection of all species of Legionella, the Wolbach modification of Giemsa stain appears to provide consistently good staining of the bacterial cells (59).…”

The Incidence and Clinical Implication of Sputum with Positive Acid-Fast Bacilli Smear But Negative in Mycobacterial Culture in a Tertiary Referral Hospital in South Korea

“…Although other respiratory pathogens, such as Nocardia, Actinomyces, Rhodococcus, Legionella micdadei , and cyst of Cryptosporidium can cause positive AFB staining (12, 13, 23, 24), and one should be aware of the potential for misdiagnosis because of these organisms (25, 26), we found no false positive AFB smears caused by these organisms of the 447 sputa with positive AFB smears screened over two years. In this context, we believe that a false positive AFB smear is rarely caused by a micro-organism other than mycobacteria.…”

“…A positive AFB smear resulting from other bacteria that may have a positive AFB smear, such as Nocardia, Actinomyces, Rhodococcus, Legionella micdadei or cysts of Cryptosporidium species (12, 13). …”