Survey of Pseudomonas aeruginosa genotypes in colonised cystic fibrosis patients.

The current authors aimed to examine whether cystic fibrosis (CF) patients in Belgium shared Pseudomonas aeruginosa genotypes and to compare the genotypes of isolates from the same patients during two consecutive years. A Belgian databank of the P. aeruginosa genotypes of all colonised CF patients was created. Sputum samples from a total of 276 P. aeruginosa colonised patients during 2003, and from a subgroup of 95 patients in 2004, were analysed. Patients were asked about any social contact between each other by questionnaire. All P. aeruginosa isolates exhibiting different colonial morphology on McConkey agar were first genotyped using arbitrarily primed PCR, whereafter single representatives of each randomly amplified polymorphic DNA-type were further genotyped by fluorescent amplified fragment length polymorphism analysis. In the 213 patients from whom P. aeruginosa could be cultured (resulting in 910 isolates), a total of 163 genotypes were found. The majority (75%) of patients harboured only one genotype. In most of the limited number of clusters, previous contacts between patients could be suspected. In 80% of the patients studied during both years, P. aeruginosa genotype remained unchanged. In conclusion, most colonised cystic fibrosis patients harbour only one Pseudomonas aeruginosa genotype, despite showing different colonial morphotypes. The number of clusters is limited, and most patients seem to retain the same genotypic strain during both years.

Epidemiology of Burkholderia cepacia complex colonisation in cystic fibrosis patients.

In Belgian cystic fibrosis (CF) clinics, sputum samples are evaluated on selective MAST medium routinely every 3 months. In this study, in 1993 and 1999, isolates were further examined by recA restriction fragment length polymorphism analysis and pulsed-field gel electrophoresis of genomic DNA restricted with SpeI. In 1993, 12 patients were colonised with Burkholderia cepacia complex (Bcc): B. cenocepacia (n=6), B. multivorans (n=3), B. stabilis (n=3). Four patients were colonised with the same B. cenocepacia strain; two with the same B. stabilis strain. After 5 yrs, three B. cenocepacia- and one B. multivorans-colonised patients had died. In 1999, Bcc was isolated in 12 patients: B. multivorans (n=9), B. stabilis (n=1) and B. cenocepacia (n=2). Three patients were colonised by the same B. multivorans strain. Compared to matched controls, the 5 yr outcome was poor; four B. cepacia patients died and none of the control patients died. Lung-function evolution was poor. In conclusion, the rate of colonisation in Belgian cystic fibrosis patients is stable and low. Burkholderia cenocepacia was most prevalent in 1993; Burkholderia multivorans in 1999. The cross-infection rate is low. Three patients had transient colonisation. The impact of Burkholderia cepacia complex on morbidity in the Belgian cystic fibrosis population is high and not limited to Burkholderia cenocepacia.

Dose-response study of oxitropium bromide inhaled as a nebulised solution.

Twelve patients suffering from partially reversible chronic obstructive pulmonary disease (COPD) took past in a single blind, randomised, 4-way cross-over trial to determine the optimal dose and duration of action of the anticholinergic agent oxitropium bromide (OTB) inhaled as a nebulised solution. Single doses of 500, 1000, 1500 and 2000 micrograms nebulised OTB were compared during a 6 hour-observation period. Lung function test results indicated that 500 and 1000 micrograms OTB only induced slight bronchodilatation, whereas 1500 and 2000 micrograms OTB produced a significantly greater increase in mean FEV1 compared to 500 micrograms. There was a trend for 2000 micrograms to be superior to 1000 micrograms, but 2000 micrograms and 1500 micrograms were not significantly different. Significant bronchodilatation (> 15% rise in FEV1 from baseline) persisted for 6 h after 1500 micrograms. A significant decrease in airway resistance (Raw) was observed following inhalation of 2000 micrograms. The mean decrease in Raw was 33% after 30 min, 20% after 4 h and 12% after 6 h. In this trial, 2000 micrograms OTB administered by an ultrasonic nebuliser was the optimal dose, but a satisfactory result was also obtained with 1500 micrograms.

Long-term follow-up of pulmonary disease caused by Mycobacterium avium in a previously healthy patient.

A 64-year-old white male with cavitary lung disease is presented. Mycobacterium avium was isolated from sputa and gastric lavage and the American Thoracic Society criteria for nontuberculous mycobacterial disease were met. Seven years follow-up and treatment regimens are discussed. This case illustrates that medical treatment of M. avium pulmonary disease can be disappointing and requires regular clinical, radiological, microbiological and haematological reassessment to evaluate efficacy and toxicity of therapy. Despite in vitro resistance to the standard antimycobacterial agents, prolonged treatment regimens can be successful and are the therapy of choice. Another drug combination, based on in vitro susceptibility patterns, has to be started for patients who fail to respond or who relapse. Lifelong treatment may be necessary to keep the patient stable and to prevent further destruction of lung parenchyma.

Frequency of the phenylalanine deletion (delta F508) in the CF gene of Belgian cystic fibrosis patients.

Cloning and sequencing of the CF gene has identified a three-base-pair deletion (delta F508) responsible for CF in the majority of CF patients (Kerem et al. 1989). We have used the polymerase chain reaction with oligonucleotide primers bridging the delta F508 deletion to analyze the presence or absence of this mutation in the Belgian CF population. The delta F508 mutation was present in 80% (57 on 71) of CF chromosomes from 36 unrelated Belgian CF families from the region of Antwerp. This mutation was associated with haplotype B for the KM.19-XV-2c RFLPs as 93% (53 on 57) of the CF chromosomes with the delta F508 mutation carried haplotype B.

Discriminatory role of history, skin testing and radio-allergo-sorbent test (RAST) in type I-mediated respiratory disease.

The discriminatory role of history, skin testing with common inhalant allergens and RAST was evaluated in patients suffering from asthma, rhinitis, cough, or various combinations of these disorders. Patients were further subdivided into allergic (type I allergy) or non-allergic based on these criteria. When there was any doubt about the allergic etiology, allergen inhalation provocation was performed. Each diagnostic technique was evaluated by means of studying an index, corresponding to an overall evaluation of the importance of the technique studied. For each of these indexes significant differences were found between allergic and non-allergic patients: RAST index proved to be most discriminatory, followed by the history index, whereas the skin test- index was only slightly different between allergic and non-allergic patients. Comparison of the results of the RAST-index before and after the introduction of anti-IgE with specificity for D 2 reveals that the introduction of this new anti-IgE increases the RAST-index values significantly in allergic patients, but not in non-allergic patients. Although the RAST is most discriminatory, the results of this assay have to be evaluated critically since positive allergen provocation tests are still found in 17.7% of patients with negative RAST results, whereas RAST classes 3 and 4 are accompanied 36.8 and 6.4% of the patients respectively with negative provocation tests.