Patient cohorting and infection control.
Patients with cystic fibrosis (CF) have an abnormal propensity for recurrent and chronic infections of the lower respiratory tract (LRT), and the most common cause of a shortened lifespan is chronic infection with Pseudomonas aeruginosa. A few other gram-negative organisms, primarily Burkholderia cepacia complex have, however, emerged as serious pathogens capable of establishing chronic LRT infection. Details of these and other CF pathogens can be found in the article by Dr. John LiPuma, Burkholderia and Emerging Pathogens in Cystic Fibrosis, in this issue. Chronically infected patients constitute a major microbial reservoir from which noninfected patients can be infected with both P. aeruginosa and B. cepacia complex by direct patient-to-patient transmission, and possibly also by exposure to contaminated environments. Other more rare pathogens such as Stenotrophomonas maltophilia, Achromobacter xylosoxidans, and nontuberculous mycobacteria (NTM) appear less capable of causing patient-to-patient transmission. Both the physical proximity and the duration of exposure of noninfected patients to patients chronically infected with P. aeruginosa and B. cepacia complex are important determinants of the risk of cross-infection. Cohorting of patients according to presence or absence of specific pathogens coupled with conventional hygienic precautions can, however, lead to a decrease in incidence and prevalence of chronic infections with these two species, wherefore patient cohorting is now an integral component of infection control in patients with CF.