Illness and Diseases

Cystic fibrosis (CF) is an autosomal recessive disease characterized by defective ion channels, resulting in multiorgan dysfunction, most notably affecting the respiratory tract. The alteration in pulmonary environment is associated with increased susceptibility to bacterial infections. These bacterial infections and the ensuing infl ammation damage the airway epithelium and cause recurrent episodes of acute exacerbations, leading ultimately to respiratory failure. Respiratory infections account for 80%–90% of deaths of patients with CF. Recent advances in bacterial taxonomy and improved microbial identifi cation methods have led to increasing recognition of the complexity of microbial ecology of the CF lung.
Thus, infections of the lung in patients with CF are now considered as polymicrobial infections. In addition to well recognized CF pathogens (e.g., Staphylococcus aureus, Pseudomonas aeruginosa, Haemophilus infl uenzae, and Burkholderia cepacia complex) numerous other opportunistic bacteria have been recently reported, such as Stenotrophomonas maltophila, Achromobacter xylosoxydans, and Inquilinus limosus and methicillin-resistant S. aureus and mucoid P. aeruginosa. The first difficulty in studying infections in the lungs of patients with CF is that many bacteria present in the lung cannot be isolated from sputum either because of their fastidious growth requirements or because of the presence of other more common CF-related pathogens, including P. aeruginosa, S. aureus, H. infl uenzae, and Branhamella catarrhalis, that might ordinarily overgrow other bacteria in culture. Second, correct identifi cation of bacteria in patients with CF remains challenging because phenotype variation is a common feature during chronic infection of the lung (4,9).
Consequently, the list of bacteria that can be recovered from sputum specimens of patients with CF may be underestimated, and new or emerging bacteria that could be responsible for outbreaks in this population are not easily detected. Correct identifi cation of these bacteria is not easily achieved. Several studies have reported the use of matrix-assisted laser desorption ionization time-of-fl ight (MALDI-TOF) mass spectrometry as a powerful tool with good and reproducible results for rapid identifi cation of clinical isolates in the microbiology laboratory as well as for identifying Outbreak of Corynebacterium pseudodiphtheriticum Infection in Cystic Fibrosis Patients, France Fadi Bittar, Carole Cassagne, Emmanuelle Bosdure, Nathalie Stremler, Jean-Christophe Dubus, Jacques Sarles, Martine Reynaud-Gaubert, Didier Raoult, and Jean-Marc Rolain Emerging Infectious Diseases.
These authors contributed equally to this article. Author affi liations: Université de la Méditerranée, Marseille, France (F. Bittar, C. Cassagne, D. Raoult, J.-M. Rolain); Hôpital Timone, Marseille (E. Bosdure, N. Stremler, J.-C. Dubus, J. Sarles); and Hôpital Sainte-Marguerite, Marseille (M. Reynaud-Gaubert) DOI: 10.3201/eid1608.100193 RESEARCH nonfermenting gram-negative bacteria in patients with CF.
This method is simple, rapid, easy to perform, inexpensive, and may ultimately replace routine phenotypic assays. We report the clinical and microbiologic features of patients with CF who were infected or colonized by C. pseudodiphtheriticum. The index case-patient was a 9-year-old girl with fever and cough; a coryneform bacterium was isolated in pure culture from her sputum. After this fi rst case, several other children with CF were found to be infected by coryneform bacteria; thus, we decided to investigate the possibility of an endemic transmission in this population. Isolated strains were identifi ed by using existing phenotypic and molecular methods as well as MALDI-TOF to decipher the relationship between these strains. Finally, a new real-time PCR with TaqMan probe (Applied Biosystems, Courtaboeuf, France) was developed and used in a retrospective analysis to detect these coryneform bacteria in our population with CF.