J.L. Whitehouse

Association between Hypermutator Phenotype, Clinical Variables, Mucoid Phenotype, and Antimicrobial Resistance in Pseudomonas aeruginosa

ABSTRACT The presence of hypermutator Pseudomonas aeruginosa was associated with poorer lung function in patients at the Adult West Midlands CF Unit. Mucoid isolates were more likely to be hypermutators. The presence of resistant mutant subpopulations was associated with hypermutator phenotype but was not good enough to be used as a test for this phenotype.

Pseudomonas aeruginosa quorum sensing molecules correlate with clinical status in cystic fibrosis

Pseudomonas aeruginosa produces quorum sensing signal molecules that are potential biomarkers for infection. A prospective study of 60 cystic fibrosis patients with chronic P. aeruginosa, who required intravenous antibiotics for pulmonary exacerbations, was undertaken. Clinical measurements and biological samples were obtained at the start and end of the treatment period. Additional data were available for 29 of these patients when they were clinically stable. Cross-sectionally, quorum sensing signal molecules were detectable in the sputum, plasma and urine of 86%, 75% and 83% patients, respectively. They were positively correlated between the three biofluids. Positive correlations were observed for most quorum sensing signal molecules in sputum, plasma and urine, with quantitative measures of pulmonary P. aeruginosa load at the start of a pulmonary exacerbation. Plasma concentrations of 2-nonyl-4-hydroxy-quinoline (NHQ) were significantly higher at the start of a pulmonary exacerbation compared to clinical stability (p<0.01). Following the administration of systemic antibiotics, plasma 2-heptyl-4-hydroxyquinoline (p=0.02) and NHQ concentrations (p<0.01) decreased significantly. In conclusion, quorum sensing signal molecules are detectable in cystic fibrosis patients with pulmonary P. aeruginosa infection and are positively correlated with quantitative measures of P. aeruginosa. NHQ correlates with clinical status and has potential as a novel biomarker for P. aeruginosa infection. P. aeruginosa QS molecules correlate with clinical status in cystic fibrosis and are biomarkers for infection http://ow.ly/MhzZp

Cross-Sectional and Longitudinal Multilocus Sequence Typing of Pseudomonas aeruginosa in Cystic Fibrosis Sputum Samples

ABSTRACT Multilocus sequence typing (MLST) is a genetic typing tool designed to provide information about the relatedness of isolates at the core genome level. The utility of MLST in regard to cystic fibrosis (CF)-related infection with Pseudomonas aeruginosa is unknown. The molecular clock speed of the MLST genes was studied using 219 colonies isolated longitudinally from 49 patients with CF. A cross-sectional study examining 27 to 46 colonies per sputum sample for samples from 16 patients was also undertaken. The molecular clock speed was estimated to be 2.05 × 10−5 (upper 95% confidence limit) or 4.75 × 10−6 (50% confidence limit) point mutations per nucleotide per year. In the cross-sectional study, 50% of patients were infected with more than one sequence type. There was evidence of point mutations, recombination events, and coinfection with epidemic and unique strains. A clonal complex that was highly genetically distinct from the rest of the P. aeruginosa population was identified. The MLST scheme uses genes with an appropriate clock speed and provides useful information about the genetic variation of P. aeruginosa within and between patients with CF.

Clinical outcomes of pandemic (H1N1) 2009 influenza (swine flu) in adults with cystic fibrosis.

Patients with cystic fibrosis (CF) suffer recurrent bacterial pulmonary infections, but viral infections can also cause acute clinical deterioration.1 Certain patient groups suffer increased morbidity following pandemic (H1N1) 2009 influenza (swine flu),2 but there are few previous reports of outcomes in individuals with CF.3 4 The West Midlands, along with Greater London, has had the highest incidence of H1N1 influenza in the UK.5 We therefore examined the outcomes of patients diagnosed with H1N1 influenza at the West Midlands Adult CF Centre. From June 2009 to April 2010 all adults with CF at our regional centre with potential H1N1 influenza had nasopharyngeal swabs tested …

Intussusception in Adults with Cystic Fibrosis: A Case Series with Review of the Literature

Intussusception occurs when a proximal segment of bowel (intussusceptum) telescopes into the lumen of the adjacent distal segment (intussuscepiens). It is a relatively common cause of an acute abdomen in the first two years of life, but is uncommon in older children [1]. The diagnosis is rare in adult life, with presentations in adulthood comprising 5% of all intussusceptions and 1% of bowel obstructions [2]. In children it is most commonly idiopathic, in contrast with adults, for most of whom an underlying etiology is found. Cystic fibrosis (CF) is the most common fatal inherited condition in Caucasians [3]. It is caused by abnormal function of the cystic fibrosis transmembrane conductance regulator (CFTR), an epithelial chloride channel. This primary defect causes epithelial secretions to be abnormally dehydrated and viscous, affecting several organs including the lungs, pancreas, intestines, and liver. CF is a well-recognized risk factor for childhood intussusception, with an incidence of 1% reported in the largest case series [4]. The peak age of presentation in this case series was between 9 and 12 years of age, much older than in the nonCF population. Although the clinical presentation and management of intussusception in children with CF is well described, that of adults is less well characterized. We therefore present a case series of CF adults diagnosed with symptomatic intussusception at our centers and perform a systematic review of the literature in order to identify previously described cases. Our aim is to examine the clinical and imaging findings of intussusception in CF adults in order to identify features of the presentation that should suggest this diagnosis.

Living with cystic fibrosis-related diabetes or type 1 diabetes mellitus: a comparative study exploring health-related quality of life and patients' reported experiences of hypoglycaemia.

Objectives: To compare patients with type 1 diabetes mellitus (T1DM) or cystic fibrosis-related diabetes (CFRD) on frequency and severity of symptoms suggestive of hypoglycaemia and diabetes-specific health-related quality of life (HRQoL). Methods: This was a cross-sectional comparison study. Participants with T1DM or CFRD completed a questionnaire that assessed symptoms suggestive of hypoglycaemia and diabetes-specific HRQoL, and recorded episodes of low blood sugars in a prospective diary. Comparisons of responses were conducted, and Pearson product correlations were determined between HRQoL scores and other continuous variables. HRQoL scores were compared between the groups after adjusting for confounding factors. Results: Diabetes in cystic fibrosis (CF) patients had a less negative impact on HRQoL than in T1DM patients. Both groups experienced hypoglycaemia, but loss of consciousness or needing help was more common in T1DM patients. Symptoms suggestive of hypoglycaemia were less of a problem for CFRD patients in terms of severity, with T1DM patients having more neuroglycopenic symptoms. Discussion: Although the same percentage of patients in both groups reported experiencing hypoglycaemia, severity (e.g. symptoms and loss of consciousness) was higher for those with T1DM. Symptoms of hypoglycaemia appear to have a significant impact on HRQoL, and could account for the worse HRQoL in T1DM patients.

Diagnostic and prognostic significance of systemic alkyl quinolones for P. aeruginosa in cystic fibrosis: a longitudinal study

Background Pulmonary P. aeruginosa infection is associated with poor outcomes in cystic fibrosis (CF) and early diagnosis is challenging, particularly in those who are unable to expectorate sputum. Specific P. aeruginosa 2-alkyl-4-quinolones are detectable in the sputum, plasma and urine of adults with CF, suggesting that they have potential as biomarkers for P. aeruginosa infection. Aim To investigate systemic 2-alkyl-4-quinolones as potential biomarkers for pulmonary P. aeruginosa infection. Methods A multicentre observational study of 176 adults and 68 children with CF. Cross-sectionally, comparisons were made between current P. aeruginosa infection using six 2-alkyl-4-quinolones detected in sputum, plasma and urine against hospital microbiological culture results. All participants without P. aeruginosa infection at baseline were followed up for one year to determine if 2-alkyl-4-quinolones were early biomarkers of pulmonary P. aeruginosa infection. Results Cross-sectional analysis: the most promising biomarker with the greatest diagnostic accuracy was 2-heptyl-4-hydroxyquinoline (HHQ). In adults, areas under the ROC curves (95% confidence intervals) for HHQ analyses were 0.82 (0.75–0.89) in sputum, 0.76 (0.69–0.82) in plasma and 0.82 (0.77–0.88) in urine. In children, the corresponding values for HHQ analyses were 0.88 (0.77–0.99) in plasma and 0.83 (0.68–0.97) in urine. Longitudinal analysis: Ten adults and six children had a new positive respiratory culture for P. aeruginosa in follow-up. A positive plasma HHQ test at baseline was significantly associated with a new positive culture for P. aeruginosa in both adults and children in follow-up (odds ratio (OR) = 6.67;-95% CI:-1.48–30.1;-p = 0.01 and OR = 70; 95% CI: 5–956;-p < 0.001 respectively). Conclusions AQs measured in sputum, plasma and urine may be used to diagnose current infection with P. aeruginosa in adults and children with CF. These preliminary data show that plasma HHQ may have potential as an early biomarker of pulmonary P. aeruginosa. Further studies are necessary to evaluate if HHQ could be used in clinical practice to aid early diagnosis of P. aeruginosa infection in the future.

“Cepacia syndrome” associated with Burkholderia cepacia (Genomovar I) infection in an adolescent with cystic fibrosis

To the Editor: Burkholderia cepacia was first described as an opportunistic organism in patients with cystic fibrosis (CF) in 1972 and was recognized as being pathogenic in CF in the 1980’s. In 1997, Vandamme et al. identified five distinct genomic species of B. cepacia, which collectively they termed the B. cepacia complex (BCC). Subsequent taxonomic studies have revealed that the BCC consists of at least 17 species, with B. cenocepacia (formerly genomovar III) andB. multivorans (formerly genomovar II) most commonly infecting individuals with CF. B. cepacia (formerly genomovar I) is seen in approximately 3% of BCC-infected CF individuals and is generally considered to be less virulent than B. cenocepacia and B. multivorans. Acquisition of BCC is associated with an accelerated decline of lung function, lower body mass index, increased morbidity, more frequent outpatient visits, increased hospitalization and decreased survival, both before and after lung transplantation. Outcomes following acquisition are however very variable, ranging from asymptomatic carriage to ‘‘cepacia syndrome,’’ an almost universally fatal necrotising pneumonia. B. cenocepacia and B. multivorans are the species most commonly implicated in causing cepacia syndrome. We present the first reported case of cepacia syndrome developing in association with B. cepacia infection. A 17-year-old female CF patient was admitted to our regional adult CF centre with worsening respiratory symptoms. She had been diagnosed with CF at 8 months of agewith delta F508 homozygous genotype and positive sweat test. Pseudomonas aeruginosa, Haemophilus influenzae, and Ralstonia pickettii had previously been intermittently cultured from her sputum. B. cepacia was first isolated from her sputumwhen shewas 9 years of age and this organism had been cultured onmultiple occasions over the intervening years. CF-related complications included exocrine pancreatic insufficiency and allergic bronchopulmonary aspergillosis (ABPA) for which she received long-term oral prednisolone. She had also suffered bacterial meningitis at the age of 6 months with consequent significant sensorineural hearing loss. At 16 years of age she transitioned to adult CF care, at which stage she was relatively healthy, with body weight 63 kg (BMI 25.8), FEV1 2.8 L (101% predicted) and FVC 3.35L (105% predicted). She had required intermittent courses of intravenous antibiotics as a child and young adult, most recently a 2-week course of ceftazidime and tobramycin 7 months previously. Due to the patient’s fears of further ototoxicity she was started on nebulised meropenem therapy, rather than nebulised tobramycin, soon after transition. Six months following transition, she was admitted to her local hospital with sore throat, hoarse voice, fevers, streaky haemopytsis and 2 kg weight loss. She was felt to have a viral upper respiratory tract infection and started on oral oseltamivir due to concerns over H1N1 pandemic influenza, although throat swabs tested negative by viral PCR. She received 10 days of intravenous ceftazidime and tobramycin, but since shewas not improving clinically she was admitted to the adult CF centre. She subsequently received intravenous hydrocortisone, ceftazidime, meropenem, and temocillin, as well as chest physiotherapy including use of high-frequency chest wall oscillation (the Vest). In addition she had high random blood glucose measurements suggestive of new onset CF-related diabetes (CFRD), for which she commenced subcutaneous insulin therapy. The chest radiograph showed bilateral multifocal consolidation and high resolution chest CT scan confirmed extensive bilateral consolidation but also demonstrated multiple lung abscesses and mediastinal lymphadenopathy. In view of these radiological findings, flucloxacillin and metronidazolewere added in an attempt to cover potential

67 Clinical outcomes and patient satisfaction following initiation of the TOBI Podhaler in CF adults

In CF patients with the F508del mutation, vertebral fractures and subsequent dorsal kyphosis decrease pulmonary function, thus accelerating the course of the disease. We discovered a defective CFTR-mediated Cl− channel activity and deficit of osteoprotegerin production by primary osteoblasts (the cells that form bone) of a 25-yr-old CF male (Gimenez A., 2012). Homozygous F508del-CFTR mice exhibit a severe osteopenic phenotype (Le Henaff C., 2012). Miglustat (N butyldeoxynojyrimicin) was reported to normalize CFTR-dependent chloride transport in nasal mucosa in F508del CF mice. We evaluated the efficacy of oral miglustat treatment in restoring bone mass in CF mice. The bone microarchitecture of CF mice, relative to wild type (WT) littermates was evaluated after an administration of 120mg/kg/day miglustat for 28 days using in vivo micro-CT, bone histomorphometry and dynamic parameters of bone formation. Levels of two serum growth factors, insulin-like growth factor 1 (IGF-1) and 17b-estradiol (E2) were determined. A once-a-day oral treatment with miglustat normalized bone volume and improved bone micro-architecture of the lumbar spine in CF mice after 4 weeks. This increase of bone volume was accompanied to both an increased bone formation and serum E2 level with no changes in IGF-1 level in miglustat-treated F508del mice. This study provides first evidence that oral administration of miglustat increases bone mass and formation in CF mice; these findings support the therapeutic potential of miglustat in patients with CF-related bone disease. Supported by Association Vaincre la Mucoviscidose, France; miglustat kindly provided by Actelion Pharmaceuticals, Switzerland.

Improving the care of patients with cystic fibrosis (CF)

Background The West Midlands Adult Cystic Fibrosis (CF) Centre based at Birmingham Heartlands Hospital provides care for adults with CF in the West Midlands. People with CF are prone to pulmonary exacerbations, which often require inpatient admission for intravenous antibiotics. We observed that the admission process was efficient during working hours (9:00–17:00, Monday–Friday) when the CF team are routinely available, but out-of-working hours, there were delays in these patients being clerked and receiving their first antibiotic dose. We were concerned that this was resulting in quality and potential safety issues by causing delays in starting treatment and prolonging hospital inpatient stays. We therefore undertook a quality improvement project (QIP) aimed at addressing these issues. An initial survey showed median time to clerk of 5 hours, with 60% of patients missing their first dose of antibiotics and mean length of stay of 16 days. Methods We applied the Plan-Do-Study-Act (PDSA) cycle approach, with the first PDSA cycle involving raising awareness of the issue through education to doctors, nurses and patients. Results This led to a reduction of median time to clerk from 5 to 2 hours with 23% of patients missing their first antibiotic dose and mean length of stay reducing to 14 days. The second cycle involved introducing an admissions checklist and displaying education posters around the hospital, resulting in median time to clerk remaining at 2 hours but only 20% of patients missing their first antibiotic dose and the mean length of stay remaining at 14 days. Conclusion This QIP has improved the out-of-hours admissions process for adults with CF in our centre. We plan to review the longer term effects of the project including sustainability, effects on clinical outcomes and patient satisfaction.