Isolation medium for the recovery of Pseudomonas cepacia from respiratory secretions of patients with cystic fibrosis

Abstract

A new medium for the isolation of Pseudomonas cepacia from respiratory tract secretions of patients with cystic fibrosis (CF) is described. This medium consists of inorganic salts, 0.5% pyruvate, and 0.1% proteose peptone as nutritive components and 0.0001% crystal violet, 0.15% bile salts, 100 ,ug of ticarcillin per ml, and 300 U of polymyxin B per ml as selective agents. The medium, designated PC medium, supported superior growth of 38 of 50 stock isolates of P. cepacia after 48 h of incubation when compared with MacConkey agar (O of 50). The medium completely inhibited the growth of 112 of 124 stock isolates of organisms commonly found in respiratory secretions of CF patients. Cultures were made on PC medium with respiratory secretions of 169 CF patients. P. cepacia was recovered from 35 patients with isolates on PC medium but from only 21 patients with isolates on MacConkey agar. Of 221 other potentially pathogenic isolates found in these specimens, only six (two Pseudomonas aeruginosa isolates, two molds, one yeast, and one Serratia marcescens isolate) grew on PC medium. PC medium should facilitate the recovery of P. cepacia from CF patients.

Are lower airway or throat cultures predictive of sinus bacteriology in cystic fibrosis?

“…Burkholderia cepacia-selective agar was used for recovery of B. cepacia and similar organisms. 10,11 Cultures and stains for viruses, fungi, and mycobacteria were carried out on all BALF samples.…”

Infection control recommendations for patients with cystic fibrosis: Microbiology, important pathogens, and infection control practices to prevent patient-to-patient transmission

“…With the emergence of B. cepacia complex strains as significant pathogens in CF patients, the need for selective May 2003 media for these organisms became apparent. The first of these, Pseudomonas cepacia (PC) agar, was described by Gilligan et al in 1985 and contained nutrients with crystal violet, bile salts, and ticarcillin and polymyxin as selective agents. 107 In a study of 169 specimens from CF patients, B. cepacia complex was isolated from 35 specimens using PC agar and from only 21 using MacConkey agar.…”

“…The first of these, Pseudomonas cepacia (PC) agar, was described by Gilligan et al in 1985 and contained nutrients with crystal violet, bile salts, and ticarcillin and polymyxin as selective agents. 107 In a study of 169 specimens from CF patients, B. cepacia complex was isolated from 35 specimens using PC agar and from only 21 using MacConkey agar. Conversely, non-cepacia organisms were inhibited by PC agar; 221 potential pathogens were isolated on nonselective media, but only 6 were recovered on PC agar.…”

Virulence factors of Burkholderia cepacia

“…B. cepacia is nutritionally versatile, with minimal growth requirements and the ability to survive in unfavourable environments: it has been isolated from disinfectants and antiseptics and can even use penicillin G as a nutrient [8][9][10][11]. The organism is intrinsically resistant to most antibiotics, and even if individual strains show in vitro susceptibility to an antibiotic, there is little clinical response [10,[12][13][14][15].…”