Cavitary Pneumonia in an AIDS Patient Caused by an Unusual Bordetella bronchiseptica Variant Producing Reduced Amounts of Pertactin and Other Major Antigens

Abstract

Although Bordetella bronchiseptica can infect and colonize immunocompromised humans, its role as a primary pathogen in pneumonia and other respiratory processes affecting those patients remains controversial. A case of cavitary pneumonia caused by B. bronchiseptica in an AIDS patient is presented, and the basis of the seemingly enhanced pathogenic potential of this isolate (designated 814) is investigated. B. bronchiseptica was the only microorganism recovered from sputum, bronchoalveolar lavage fluid, and samples taken through the protected brush catheter. Unlike previous work reporting the involvement of B. bronchiseptica in cases of pneumonia, antibiotic treatment selected on the basis of in vitro antibacterial activity resulted in clearance of the infection and resolution of the pulmonary infiltrate. Although isolate 814 produced reduced amounts of several major antigens including at least one Bvg-activated factor (pertactin), the molecular basis of this deficiency was found to be BvgAS independent since the defect persisted after the bvgAS locus of isolate 814 was replaced with a wild-type bvgAS allele. Despite its prominent phenotype, isolate 814 displayed only a modest yet a significant deficiency in its ability to colonize the respiratory tracts of immunocompetent rats at an early time point. Interestingly, the antibody response elicited by isolate 814 in these animals was almost undetectable. We propose that isolate 814 may be more virulent in immunocompromised patients due, at least in part, to its innate ability to produce low amounts of immunogenic factors which may be required at only normal levels for the interaction of this pathogen with its immunocompetent natural hosts.

Evaluation of Real-Time PCR for Detection of and Discrimination between Bordetella pertussis , Bordetella parapertussis , and Bordetella holmesii for Clinical Diagnosis

“…In the rare event that this occurs, the PCR product from the B. parapertussis PCR can be sequenced and B. holmesii infection can be distinguished from a dual infection. Of other Bordetella species such as B. bronchiseptica, B. avium, B. trematum, and B. hinzii, it is only B. bronchiseptica that has been reported to cause respiratory infection in immunocompromised hosts (14). So the possibility VOL.…”

Microbiological and clinical aspects of respiratory infections associated with Bordetella bronchiseptica

“…Most reports on B. bronchiseptica infection/colonization in humans correspond to small case series or single case reports of debilitated or immunosuppressed patients (Berkowitz et al, 2007;Dworkin et al, 1999;Garcia San Miguel et al, 1988;Lorenzo-Pajuelo et al, 2002;Wernli et al, 2011). The reason why only a limited number of cases of B. bronchiseptica are reported could be due to the fact that it is considered a respiratory commensal.…”

“…However, it is an uncommon cause of infection in humans. Sporadic cases of infection by B. bronchiseptica have been reported and are particularly associated with patients who are debilitated or immunosuppressed (Lorenzo-Pajuelo et al, 2002;Ner et al, 2003;Spilker et al, 2008). The organism is less commonly isolated from immunocompetent individuals (De la Torre et al, 2012;Rath et al, 2008).…”

External Quality Assessment for Molecular Detection of Bordetella pertussis in European Laboratories

“…Likewise, B. bronchiseptica has been isolated from AIDS patients (27,47) and cystic fibrosis patients (48). Although both B. holmesii and B. bronchiseptica have been implicated as infrequent causes of a pertussis-like syndrome and other respiratory illnesses (26), the clinical relevance of the presence of these rare microorganisms in human respiratory samples needs further investigation.…”