Identification of Bordetella spp. in respiratory specimens from individuals with cystic fibrosis

Bordetella spp. are not normally included when considering the opportunistic bacterial species that are typically involved in respiratory tract infections in individuals with cystic fibrosis (CF). By using a combination of bacterial genotyping and 16S rDNA sequencing, Bordetella spp. were identified in cultures obtained from 43 individuals with CF. Most (n = 23) patients were infected with Bordetella bronchiseptica/parapertussis; five were infected with Bordetella hinzii, four with Bordetella petrii, three with Bordetella avium, and eight with unidentified Bordetella spp. Consideration should be given to the presence of these organisms in the evaluation of CF sputum cultures.

Recovery of Burkholderia cenocepacia strain PHDC from cystic fibrosis patients in Europe

BACKGROUND

Burkholderia cenocepacia can cause life threatening respiratory tract infections in patients with cystic fibrosis (CF) and has a significant impact on survival. There is extensive evidence for patient to patient spread and nosocomial transmission of this organism, and several widespread B cenocepacia strains have been described including the transatlantic ET12 clone. A study was performed to compare B cenocepacia isolates recovered from CF patients receiving care in several European countries and strains isolated from other clinical samples and the environment, with reference isolates from the epidemic B cenocepacia strain PHDC which has so far only been recovered from CF patients and soil in the USA.

METHODS

A large collection of B cenocepacia isolates, including a large number recovered from CF patients receiving care in several European countries, Canada and the USA, were genotyped by means of randomly amplified polymorphic DNA typing (RAPD) and rep-PCR using the BOX-A1R primer (BOX-PCR).

RESULTS

Nineteen Burkholderia cenocepacia isolates cultured from clinical samples in Europe (18 recently recovered from CF patients in France and Italy and one recovered in 1964 from urine in the UK) showed RAPD fingerprinting patterns that were similar to patterns obtained from isolates of B cenocepacia strain PHDC. Subsequent analysis of these isolates using BOX-PCR confirmed that the European isolates and strain PHDC represent the same clone.

CONCLUSION

Strain PHDC represents a second transatlantic B cenocepacia clone capable of colonising patients with CF.

Endemicity and inter-city spread of Burkholderia cepacia genomovar III in cystic fibrosis

OBJECTIVES

We sought to determine whether the same Burkholderia cepacia complex strain has persisted as the dominant clonal lineage among patients in a large cystic fibrosis (CF) treatment center during the past 2 decades.

STUDY DESIGN

The inter-city spread of B cepacia through transfer of a colonized patient and the impact of infection control measures in containing inter-patient transmission were investigated. We analyzed all available B cepacia complex isolates recovered from 1981 to 1987 and from 1996 to 2000 at one large CF treatment center (Center A) and from 1997 to 2000 at another center (Center B). Incidence of B cepacia complex infection and infection control measures in both centers were assessed.

RESULTS

Seventeen (81%) of 21 Center A patients from whom B cepacia complex bacteria were recovered between 1981 and 1987 and 40 (97%) of 41 patients culture-positive between 1996 and 2000 were infected with the same genomovar III strain. Transfer of a colonized patient from Center A to Center B was associated with an increase in B cepacia complex infection in Center B, all of which was with the Center A dominant strain. This strain, designated PHDC, lacks both B cepacia epidemic strain and cblA markers.

CONCLUSIONS

B cepacia complex strains may remain endemic in CF treatment centers for many years. Responsible bacterial and host factors and optimal infection control measures to prevent inter-patient spread remain to be identified.

Disproportionate distribution of Burkholderia cepacia complex species and transmissibility markers in cystic fibrosis

Several distinct species (genomovars) comprise bacteria previously identified merely as Burkholderia cepacia. Understanding how these species, collectively referred to as the B. cepacia complex, differ in their epidemiology and pathogenic potential in cystic fibrosis (CF) is important in efforts to refine management strategies. B. cepacia isolates recovered from 606 CF patients receiving care at 132 treatment centers in 105 cities in the United States were assessed to determine species within the B. cepacia complex and examined for the presence of putative transmissibility markers (B. cepacia epidemic strain marker [BCESM] and cable pilin subunit gene [cblA]). Fifty percent of patients were infected with B. cepacia complex genomovar III, 38% with B. multivorans (formerly genomovar II), and 5% with B. vietnamiensis (formerly genomovar V); fewer than 5% of patients were infected with either genomovar I, B. stabilis (formerly genomovar IV), genomovar VI, or genomovar VII. BCESM was found in 46% of genomovar III isolates and not in any other species. Only one isolate, from a patient infected with the ET12 epidemic lineage, contained the complete cblA pilin subunit gene. Our data indicate a differential capacity for human infection among the phylogenetically closely related species of the B. cepacia complex. The low frequency of BCESM and cblA suggests that they are not sufficient markers of B. cepacia virulence or transmissibility.

Utility of commercial systems for identification of Burkholderia cepacia complex from cystic fibrosis sputum culture

Performances of several commercial test systems were reviewed to determine their relative levels of accuracy in identifying Burkholderia cepacia complex isolates recovered from cystic fibrosis sputum culture. Positive predictive values ranged from 71 to 98%; negative predictive values ranged from 50 to 82%. All systems misidentified B. cepacia complex. The species most frequently misidentified as B. cepacia was Burkholderia gladioli. These data support the results of previous studies that recommend confirmatory testing, including the use of DNA-based methods, for sputum culture isolates presumptively identified as B. cepacia.