No abstract

Branhamella catarrhalis is increasingly recognized as a lower respiratory tract pathogen, particularly in chronic lung diseases. This project defines a population of patients in whom the dynamics of colonization and infection caused by this organism could be studied. A method employing pulsed field gel electrophoresis (PFGE) of genomic DNA was developed. Twenty-eight patients with bronchiectasis followed prospectively for 26.8 mo (mean) were seen monthly or bimonthly and at the time of a purulent exacerbation. Quantitative bacterial cultures were performed on sputum obtained at each visit. Six of 28 had B. catarrhalis isolated repeatedly. Viable numbers of B. catarrhalis were similar to other bacterial pathogens. Restriction fragment length polymorphism (RFLP) analysis of chromosomal DNA using PFGE was performed on 37 of the 47 isolates recovered. Each patient was colonized by two to four strains with different RFLP patterns. Duration of colonization by the same strain was 2.3 mo (mean). Strain acquisition did not correlate with exacerbation, antibiotic therapy, or season. We conclude that (1) a subset of bronchiectatic patients is colonized with B. catarrhalis, (2) RFLP is a sensitive tool to study strain acquisition, and (3) acquisition and clearance of B. catarrhalis from the respiratory tract is a dynamic process.

Aims-To establish a simple method of quantitative culture for determining the viable bacterial numbers present in expectorated sputum samples. Methods-Sputum samples were homogenised with dithiothreitol, sterile saline or glass beads to determine which method recovered the greatest number of viable bacteria. Culture broths were also incubated with dithiothreitol and sampled over time to determine its effect on bacterial viability. Sputum samples homogenised with dithiothreitol were diluted in sterile saline and sampled using either standard bacteriological loops or a precision pipette to determine which method resulted in the least variation. it has become apparent that sputum culture techniques require re-evaluation. This is particularly the case where the number of bacteria present reflects the clinical status and hence the need for, and response to, treatment.9 It has been recognised in patients with cystic fibrosis that the use of quantitative bacteriological assessment of sputum should be encouraged, firstly, to judge the significance of the bacterial species present and, secondly, to assess the therapeutic efficacy of antibiotic treatment,' but to date this has not been extended for use in other chronic lung diseases. Although several authors have described various methods for quantifying viable bacterial numbers in sputum,'1'4 no universally accepted method has been established. The aim of the studies reported here was to establish a simple, reliable method for quantitative bacterial culture of sputum, with particular reference to homogenisation, sample volume and plate inoculation technique. The variation in bacterial numbers recovered from individual sputum samples was also investigated to determine whether sampling a small portion of the expectorated sputum gives results that are representative of the sample as a whole. Methods SPUTUM SAMPLESAll samples of sputum were collected from clinically stable patients with radiologically confirmed bronchiectasis who were regularly attending a specialist outpatient clinic. On waking, patients were encouraged to perform their usual postural drainage routine and then to collect their sputum into sterile universal containers over four hours. A macroscopic assessment of the collected sputum sample was made and samples were classified as being mucoid (M), mucopurulent (MP) or purulent (P) in nature as described previously .' HOMOGENISATION TECHNIQUE Eighteen sputum samples (six M, six MP and six P) were collected from individual patients

The current study of the UK cohort of patients with AATD confirmed a higher prevalence of ulcerative colitis than would be expected in the general population, providing further evidence of a potential link between these 2 conditions. In addition, the data suggested a potential link between hypothyroidism and AATD.