Isolation of Infectious Cystic Fibrosis Patients: Results of a Systematic Review

Discovery of Pyrrolidine-2,3-diones as Novel Inhibitors of P. aeruginosa PBP3

The alarming threat of the spread of multidrug resistant bacteria currently leaves clinicians with very limited options to combat infections, especially those from Gram-negative bacteria. Hence, innovative strategies to deliver the next generation of antibacterials are urgently needed. Penicillin binding proteins (PBPs) are proven targets inhibited by β-lactam antibiotics. To discover novel, non-β-lactam inhibitors against PBP3 of Pseudomonas aeruginosa, we optimised a fluorescence assay based on a well-known thioester artificial substrate and performed a target screening using a focused protease-targeted library of 2455 compounds, which led to the identification of pyrrolidine-2,3-dione as a potential scaffold to inhibit the PBP3 target. Further chemical optimisation using a one-pot three-component reaction protocol delivered compounds with excellent target inhibition, initial antibacterial activities against P. aeruginosa and no apparent cytotoxicity. Our investigation revealed the key structural features; for instance, 3-hydroxyl group (R²) and a heteroaryl group (R¹) appended to the N-pyrroldine-2,3-dione via methylene linker required for target inhibition. Overall, the discovery of the pyrrolidine-2,3-dione class of inhibitors of PBP3 brings opportunities to target multidrug-resistant bacterial strains and calls for further optimisation to improve antibacterial activity against P. aeruginosa.

Protease inhibitors elicit anti-inflammatory effects in CF mice with Pseudomonas aeruginosa acute lung infection

Pseudomonas aeruginosa is the major respiratory pathogen in patients with cystic fibrosis (CF). P. aeruginosa-secreted proteases, in addition to host proteases, degrade lung tissue and interfere with immune processes. In this study, we aimed at evaluating the possible anti-inflammatory effects of protease inhibitors Marimastat and Ilomastat in the treatment of P. aeruginosa infection. Lung infection with the P. aeruginosa PAO1 strain was established in wild-type and cystic fibrosis transmembrane conductance regulator (CFTR) knock-out C57BL/6 mice expressing a luciferase gene under control of bovine interleukin (IL)-8 promoter. After intratracheal instillation with 150 µM Marimastat and Ilomastat, lung inflammation was monitored by in-vivo bioluminescence imaging and bacterial load in the lungs was assessed. In vitro, the effects of protease inhibitors on PAO1 growth and viability were evaluated. Acute lung infection was established in both wild-type and CFTR knock-out mice. After 24 h, the infection induced IL-8-dependent bioluminescence emission, indicating lung inflammation. In infected mice with ongoing inflammation, intratracheal treatment with 150 µM Marimastat and Ilomastat reduced the bioluminescence signal in comparison to untreated, infected animals. Bacterial load in the lungs was not affected by the treatment, and in vitro the same dose of Marimastat and Ilomastat did not affect PAO1 growth and viability, confirming that these molecules have no additional anti-bacterial activity. Our results show that inhibition of protease activity elicits anti-inflammatory effects in cystic fibrosis (CF) mice with acute P. aeruginosa lung infection. Thus, Marimastat and Ilomastat represent candidate molecules for the treatment of CF patients, encouraging further studies on protease inhibitors and their application in inflammatory diseases.

Pneumonia due to Pandoraea Apista after evacuation of traumatic intracranial hematomas:a case report and literature review

Background

Pandoraea species is a newly described genus, which is multidrug resistant and difficult to identify. Clinical isolates are mostly cultured from cystic fibrosis (CF) patients. CF is a rare disease in China, which makes Pandoraea a total stranger to Chinese physicians. Pandoraea genus is reported as an emerging pathogen in CF patients in most cases. However, there are few pieces of evidence that confirm Pandoraea can be more virulent in non-CF patients. The pathogenicity of Pandoraea genus is poorly understood, as well as its treatment. The incidence of Pandoraea induced infection in non-CF patients may be underestimated and it’s important to identify and understand these organisms.

Case presentation

We report a 44-years-old man who suffered from pneumonia and died eventually. Before his condition deteriorated, a Gram-negative bacilli was cultured from his sputum and identified as Pandoraea Apista by matrix-assisted laser desorption ionization–time-of-flight mass spectrometry (MALDI-TOF MS).

Conclusion

Pandoraea spp. is an emerging opportunistic pathogen. The incidences of Pandoraea related infection in non-CF patients may be underestimated due to the difficulty of identification. All strains of Pandoraea show multi-drug resistance and highly variable susceptibility. To better treatment, species-level identification and antibiotic susceptibility test are necessary.

Novel understandings of host cell mechanisms involved in chronic lung infection: Pseudomonas aeruginosa in the cystic fibrotic lung

As one of the most debilitating and underdiagnosed hereditary conditions across the globe, cystic fibrosis requires intensive support from the healthcare system - particularly due to the increased susceptibility to chronic infection and resulting respiratory failure which can rapidly lead to death. In turn, the prevalence and action of a certain strain of bacterium - Pseudomonas aeruginosa - has gained a great deal of interest. Life-threatening chronic infections by P. aeruginosa have been shown to involve biofilm formation, proliferation and the release of quorum-sensing signaling molecules. Understanding the mechanism cascade by which this strain attacks cells within the respiratory epithelium, most notably airway epithelial cells, could offer insight into the pathway and components, which are attractive targets for therapeutic interventions.

Stenotrophomonas maltophilia healthcare-associated infections: identification of two main pathogenic genetic backgrounds

BACKGROUND

Stenotrophomonas maltophilia is an opportunistic multi-drug-resistant bacterium responsible for healthcare-associated infections. Strategies for in-hospital infection control and management of carriers and environmental reservoirs remain controversial.

AIM

To determine the population structure of S. maltophilia strains in hospitalized infected patients and to identify putative highly pathogenic subpopulations that require upgraded infection control measures.

METHODS

Eighty-three diverse human strains of various clinical origins from 18 geographically distant hospitals were characterized phenotypically and genotypically using a multi-locus sequence typing (MLST) approach.

FINDINGS

Neither a predominant nor emerging sequence type (ST) was identified. Among the 80 typeable strains, only 29% corresponded to described STs, especially ST5 (N=6) and ST4/26/31 (N=2). The ST distribution and the phylogenic tree based on the concatenated MLST genes did not account for geographical, clinical origin or antimicrobial susceptibility clustering. A phylogenic tree that included 173 ST profiles from the MLST database and the 80 typeable strains confirmed the high genetic diversity of S. maltophilia, the previously reported genogroup organization and the predominance of genogroup 6, as it represented 41% (33/80) of the strains. Unexpectedly, genogroup 2 was the second most prevalent genogroup and included 16% (13/80) of the strains. These genogroups represented 57% (20/35) of the strains in respiratory patients and 75% (9/12) of the strains in patients with cystic fibrosis.

CONCLUSION

Beyond MLST, the over-representation of some genogroups among strains responsible for healthcare-associated infections was confirmed. Genogrouping affiliation is recommended to implement infection control measures selectively for the most pathogenic strains isolated from patient or environmental reservoirs.

Multilocus sequence typing analysis of Pseudomonas aeruginosa isolated from pet Chinese stripe-necked turtles (Ocadia sinensis)

Our research sought to characterize the phylogeny of Pseudomonas aeruginosa isolated from pet Chinese stripe-necked turtles (Ocadia sinensis) to better understand its evolutionary relation to other isolates and increase understanding of a potential zoonotic pathogen transmitted through direct contact with pet turtles. Thirty-one Pseudomonas aeruginosa isolates were obtained from both immature and adult turtles sold in pet shops in Korea. To characterize the phylogenic position of Chinese stripe-necked turtle-borne P. aeruginosa relative to other strains, multilocus sequence typing (MLST) analysis was performed due to the accessibility and breadth of MLST databases. Seven housekeeping genes (acsA, aroE, guaA, mutL, nuoD, ppsA, and trpE) were sequenced and the results were compared with data from the MLST database. The genes were further used for phylogenetic analysis of P. aeruginosa using concatenated gene fragments. Both rooted and unrooted phylogenetic trees were generated. Eleven distinct sequence types were present within the isolates among which seven were new. Expanding an unrooted phylogenetic tree to include P. aeruginosa MLST sequences isolated from various other geographic locations and sources revealed a divergent cluster containing the majority of isolates obtained from turtles. This suggests that P. aeruginosa strains particularly well-adapted for inhabiting turtles occupy a distinct phylogenetic position.

A novel method for investigating Burkholderia cenocepacia infections in patients with cystic fibrosis and other chronic diseases of the airways

BACKGROUND

Burkholderia cenocepacia is a Gram-negative, opportunistic pathogen that is a cause of morbidity and mortality in patients with cystic fibrosis (CF). Research efforts over the past few decades contributed to our understanding of these infections by identifying virulence factors. However, little is known about how this pathogen adapts to the harsh environment found inside the CF airways, which is characterized by a unique mucus containing high concentrations of inflammatory markers. The current study developed a novel model to further investigate this phenomenon.

RESULTS

Monolayers of human A549 lung carcinoma cells (HLCCs) were exposed to a mixture of artificial CF sputum medium (ASMDM) in tissue culture growth medium, and subsequently infected with B. cenocepacia K56-2 for 24 h. The data showed that this model supported B. cenocepacia growth. In addition, consistent with similar studies using current models such as CF airway tissue samples, HLCC viability was reduced by more than 70 % when grown in 60 % ASMDM and infected with B. cenocepacia compared to mock-infected controls and medium alone. Furthermore, the amount of B. cenocepacia cells associated with the HLCC monolayer was more than 10 times greater in 60 % ASMDM when compared to medium controls.

CONCLUSIONS

These findings suggest that HLCC monolayers in 60 % ASMDM serve as a valid alternative to study B. cenocepacia infections in patients with CF, and possibly other chronic diseases of the airways. Furthermore, the results obtained in this study suggest an important role for CF sputum in B. cenocepacia pathogenesis.

Two decades (1993-2012) of adult intensive care unit design: a comparative study of the physical design features of the best practice examples

In 2006, Critical Care Nursing Quarterly published a study of the physical design features of a set of best practice example adult intensive care units (ICUs). These adult ICUs were awarded between 1993 and 2003 by the Society of Critical Care Medicine (SCCM), the American Association of Critical-Care Nurses, and the American Institute of Architects/Academy of Architecture for Health for their efforts to promote the critical care unit environment through design. Since 2003, several more adult ICUs were awarded by the same organizations for similar efforts. This study includes these newer ICUs along with those of the previous study to cover a period of 2 decades from 1993 to 2012. Like the 2006 study, this study conducts a systematic content analysis of the materials submitted by the award-winning adult ICUs. On the basis of the analysis, the study compares the 1993-2002 and 2003-2012 adult ICUs in relation to construction type, unit specialty, unit layout, unit size, patient room size and design, support and service area layout, and family space design. The study also compares its findings with the 2010 Guidelines for Design and Construction of Health Care Facilities of the Facility Guidelines Institute and the 2012 Guidelines for Intensive Care Unit Design of the SCCM. The study indicates that the award-winning ICUs of both decades used several design features that were associated with positive outcomes in research studies. The study also indicates that the award-winning ICUs of the second decade used more evidence-based design features than those of the first decades. In most cases, these ICUs exceeded the requirements of the Facility Guidelines Institute Guidelines to meet those of the SCCM Guidelines. Yet, the award-winning ICUs of both decades also used several features that had very little or no supporting research evidence. Since they all were able to create an optimal critical care environment for which they were awarded, having knowledge of the physical design of these award-winning ICUs may help design better ICUs.

Genome Sequences of Two Pandoraea pnomenusa Isolates Recovered 11 Months Apart from a Cystic Fibrosis Patient

Pandoraea is an emerging respiratory pathogen capable of causing chronic lung infections in people with cystic fibrosis (CF), but the clinical significance of this infection is ambiguous. We have sequenced and annotated the genomes of two multidrug-resistant Pandoraea pnomenusa isolates recovered 11 months apart from the same CF patient.

Are strict isolation policies based on susceptibility testing actually effective in the prevention of the nosocomial spread of multi-drug-resistant gram-negative rods?

BACKGROUND

The emergence of multi-drug-resistant gram-negative rods (MDR-GNRs) has become a worldwide problem. To limit the emergence of MDR-GNRs, a tertiary care cancer center in Japan implemented a policy that requires the pre-emptive isolation of patients with organisms that have the potential to be MDR-GNRs.

METHODS

A retrospective analysis was performed. Any gram-negative bacillus isolates categorized as intermediate or resistant to at least 2 classes of antimicrobials were subjected to contact precautions. The incidence of patients with MDR-GNRs was analyzed.

RESULTS

There was no difference between the preintervention and intervention time periods in the detection rate of nonfermenting MDR-GNR species (0.15 per 10,000 vs 0.35 per 10,000 patient-days, P = .08). There was an increase in the detection rate of multi-drug-resistant Enterobacteriaceae (0.19 per 10,000 vs 0.56 per 10,000 patient-days, P = .007), which was prominent for extended-spectrum β-lactamase (ESBL)-producing organisms (0.19 per 10,000 vs 0.50 per 10,000 patient-days, P = .02).

CONCLUSIONS

Our intervention kept the emergence of multi-drug-resistant non-glucose-fermenting gram-negative bacilli to a small number, but it failed to prevent an increase in ESBL producers. Policies, such as active detection and isolation, are warranted to decrease the incidence of these bacilli.

Outbreak of Achromobacter xylosoxidans in an Italian Cystic fibrosis center: genome variability, biofilm production, antibiotic resistance, and motility in isolated strains

Cystic fibrosis (CF) patients have chronic airway infection and frequent exposure to antibiotics, which often leads to the emergence of resistant organisms. Achromobacter xylosoxidans is a new emergent pathogen in CF spectrum. From 2005 to 2010 we had an outbreak in A. xylosoxidans prevalence in our CF center, thus, the present study was aimed at deeply investigating virulence traits of A. xylosoxidans strains isolated from infected CF patients. To this purpose, we assessed A. xylosoxidans genome variability by randomly amplified polymorphic DNA (RAPD), biofilm production, antibiotic resistances, and motility. All A. xylosoxidans strains resulted to be biofilm producers, and were resistant to antibiotics usually employed in CF treatment. Hodge Test showed the ability to produce carbapenemase in some strains. Strains who were resistant to β-lactamics antibiotics, showed the specific band related to metal β-lactamase (bla_IMP-1), and some of them showed to possess the integron1. Around 81% of A. xylosoxidans strains were motile. Multivariate analysis showed that RAPD profiles were able to predict Forced Expiratory Volume (FEV1%) and biofilm classes. A significant prevalence of strong biofilm producers strains was found in CF patients with severely impaired lung functions (FEV1% class 1). The outbreak we had in our center (prevalence from 8.9 to 16%) could be explained by an enhanced adaptation of A. xylosoxidans in the nosocomial environment, despite of aggressive antibiotic regimens that CF patients usually undergo.

SNaPaer: a practical single nucleotide polymorphism multiplex assay for genotyping of Pseudomonas aeruginosa

Multilocus sequence typing (MLST) represents the gold standard genotyping method in studies concerning microbial population structure, being particularly helpful in the detection of clonal relatedness. However, its applicability on large-scale genotyping is limited due to the high cost and time spent on the task. The selection of the most informative nucleotide positions simplifies genomic characterization of bacteria. A simple and informative multiplex, SNaPaer assay, was developed and genotyping of Pseudomonas aeruginosa was obtained after a single reaction of multiplex PCR amplification and mini-sequencing. This cost-effective technique allowed the analysis of a Portuguese set of isolates (n = 111) collected from three distinct hospitals and the genotyping data could be obtained in less than six hours. Point mutations were shown to be the most frequent event responsible for diversification of the Portuguese population sample. The Portuguese isolates corroborated the epidemic hypothesis for P. aeruginosa population. SNaPaer genotyping assay provided a discriminatory power of 0.9993 for P. aeruginosa, by testing in silico several hundreds of MLST profiles available online. The newly proposed assay targets less than 0.01% of the total MLST length and guarantees reproducibility, unambiguous analysis and the possibility of comparing and transferring data between different laboratories. The plasticity of the method still supports the addition of extra molecular markers targeting specific purposes/populations. SNaPaer can be of great value to clinical laboratories by facilitating routine genotyping of P. aeruginosa.

Evidence that WapB is a 1,2-glucosyltransferase of Pseudomonas aeruginosa involved in Lipopolysaccharide outer core biosynthesis

Pseudomonas aeruginosa is an important opportunistic pathogen infecting debilitated individuals. One of the major virulence factors expressed by P. aeruginosa is lipopolysaccharide (LPS), which is composed of lipid A, core oligosaccharide (OS), and O-antigen polysaccharide. The core OS is divided into inner and outer regions. Although the structure of the outer core OS has been elucidated, the functions and mechanisms of the glycosyltransferases involved in core OS biogenesis are currently unknown. Here, we show that a previously uncharacterized gene, pa1014, is involved in outer core biosynthesis, and we propose to rename this gene wapB. We constructed a chromosomal mutant, wapB::Gm, in a PAO1 (O5 serotype) strain background. Characterization of the LPS from the mutant by Western immunoblotting showed a lack of reactivity to PAO1 outer core-specific monoclonal antibody (MAb) 5c-101. The chemical structure of the core OS of the wapB mutant was elucidated using nuclear magnetic resonance spectroscopy and mass spectrometry techniques and revealed that the core OS of the wapB mutant lacked the terminal β-1,2-linked-d-glucose residue. Complementation of the mutant with wapB in trans restored the core structure to one that is identical to that of the wild type. Eleven of the 20 P. aeruginosa International Antigenic Typing Scheme (IATS) serotypes produce LPSs that lack the terminal d-glucose residue (Glc(IV)). Interestingly, expressing wapB in each of these 11 serotypes modifies each of their outer core OS structures, which became reactive to MAb 5c-101 in Western immunoblotting, suggesting the presence of a terminal d-glucose in these core OS structures. Our results strongly suggested that wapB encodes a 1,2-glucosyltransferase.

Virulence of an emerging respiratory pathogen, genus Pandoraea, in vivo and its interactions with lung epithelial cells

Pandoraea species have emerged as opportunistic pathogens among cystic fibrosis (CF) and non-CF patients. Pandoraea pulmonicola is the predominant Pandoraea species among Irish CF patients. The objective of this study was to investigate the pathogenicity and potential mechanisms of virulence of Irish P. pulmonicola isolates and strains from other Pandoraea species. Three patients from whom the P. pulmonicola isolates were isolated have since died. The in vivo virulence of these and other Pandoraea strains was examined by determining the ability to kill Galleria mellonella larvae. The P. pulmonicola strains generally were the most virulent of the species tested, with three showing a comparable or greater level of virulence in vivo relative to another CF pathogen, Burkholderia cenocepacia, whilst strains from two other species, Pandoraea apista and Pandoraea pnomenusa, were considerably less virulent. For all Pandoraea species, whole cells were required for larval killing, as cell-free supernatants had little effect on larval survival. Overall, invasive Pandoraea strains showed comparable invasion of two independent lung epithelial cell lines, irrespective of whether they had a CF phenotype. Pandoraea strains were also capable of translocation across polarized lung epithelial cell monolayers. Although protease secretion was a common characteristic across the genus, it is unlikely to be involved in pathogenesis. In conclusion, whilst multiple mechanisms of pathogenicity may exist across the genus Pandoraea, it appears that lung cell invasion and translocation contribute to the virulence of P. pulmonicola strains.

Achromobacter xylosoxidans genomic characterization and correlation of randomly amplified polymorphic DNA profiles with relevant clinical features [corrected] of cystic fibrosis patients

Achromobacter xylosoxidans is an emerging pathogen increasingly being isolated from respiratory samples of cystic fibrosis (CF) patients. Its role and clinical significance in lung pathogenesis have not yet been clarified. The aim of the present study was to genetically characterize A. xylosoxidans strains isolated from CF patients by use of randomly amplified polymorphic DNA (RAPD) profiles and to look for a possible correlation between RAPD profiles and the patients' clinical features, such as their spirometry values, the presence of concomitant chronic bacterial flora at the time of isolation, and the persistent or intermittent presence of A. xylosoxidans strains. A set of 106 strains of A. xylosoxidans were typed by RAPD analysis, and their profiles were analyzed by agglomerative hierarchical classification (AHC) and associated with the patient characteristics mentioned above by factorial discriminant analysis (FDA). The overall results obtained in this study showed that (i) there is a marked genetic relationship between strains isolated from the same patients at different times, (ii) characteristic RAPD profiles are associated with different predicted classes for forced expiratory volume in 1 s (FEV1%), (iii) some characteristic RAPD profiles are associated with different concomitant chronic flora (CCF) profiles, and (iv) there is a significant division of RAPD profiles into "persistent strains" and "intermittent strains" of A. xylosoxidans. These findings seem to imply that the lung habitats found in CF patients are capable of shaping and selecting the colonizing bacterial flora, as seems to be the case for the A. xylosoxidans strains studied.

Molecular Characterization of Stenotrophomonas maltophilia isolates from cystic fibrosis patients and the hospital environment

OBJECTIVES

To ascertain whether cystic fibrosis (CF) patients are colonized or infected with unique or multiple strains of Stenotrophomonas maltophilia; to understand whether some strains colonize or infect more than 1 patient, indicating clonal spread; and to explore the molecular heterogeneity of hospital water isolates and their correlation with clinical isolates.

SETTING

The regional CF center of Policlinico "Umberto I" of Rome, Italy.

METHODS

The study was carried out on a random sample of S. maltophilia isolates (n = 110) collected from CF patients (n = 50) during the period 2002-2005 and on 24 water isolates obtained during a monitoring program in the first 6 months of 2005. Home environmental samplings were not performed. All isolates, which were recovered from cultures of specimens obtained in both inpatient and outpatient settings, were genotyped with DNA macrorestriction analysis with the restriction enzyme XbaI and pulsed-field gel electrophoresis.

RESULTS

One-third of the patients with repeated episodes of S. maltophilia infection or colonization hosted more than 1 strain. A potential transmission, defined as the isolation of the same strain in 2 or more patients, occurred 5 times, showing a frequency of potential transmission episodes slightly higher than previously reported. Water, taps, and sinks of the different rooms of the CF center tended to be persistently colonized with the same strain of S. maltophilia, with no correlation between clinical and water-associated isolates.

CONCLUSIONS

The study does not provide sufficient data to conclude definitively that isolation of colonized or infected CF patients and control of hospital water systems contamination would be beneficial infection control measures. Epidemiologic analytical studies that correlate the presence of S. maltophilia with clinical outcomes are strongly needed.

Viable ultramicrocells in drinking water

AIMS

To examine the diversity of cultivable 0.2 micron filtrate biofilm forming bacteria from drinking water systems.

METHODS AND RESULTS

Potable chlorinated drinking water hosts phylogenetically diverse ultramicrocells (UMC) (0.2 and 0.1 microm filterable). UMC (starved or dwarf bacteria) were isolated by cultivation on minimal medium from a flow system wall model with polyvinyl chloride (PVC) pipes. All cultivated cells (25 different isolates) did not maintain their ultra-size after passages on rich media. Cultured UMC were identified by their 16S ribosomal DNA sequences. The results showed that they were closely related to uncultured and cultured members of the Proteobacteria, Actinobacteria and Firmicutes. The isolates of phylum Actinobacteria included representatives of a diverse set of Actinobacterial families: Micrococcaceae, Microbacteriaceae, Dermabacteraceae, Nocardiaceae and Nocardioidaceae.

CONCLUSIONS

This study is the first to show an abundance of cultivable UMC of various phyla in drinking water system, including a high frequency of bacteria known to be involved in opportunistic infections, such as Stenotrophomonas maltophilia, Microbacterium sp., Pandoraea sp. and Afipia strains.

SIGNIFICANCE AND IMPACT OF THE STUDY

Chlorinated tap water filtrate (0.2 and 0.1 microm) still harbours opportunistic micro-organisms that can pose some health threat.

Pulmonary bacterial pathogens in cystic fibrosis patients and antibiotic therapy: a tool for the health workers

Cystic fibrosis is the most common and best known genetic disease involving a defect in transepithelial Cl- transport by mutations in the CF gene on chromosome 7, which codes for the cystic fibrosis transmembrane conductance regulator protein (CFTR). The most serious symptoms are observed in the lungs, augmenting the risk of bacterial infection. The objective of this review was to describe the bacterial pathogens colonizing patients with cystic fibrosis. A systematic search was conducted using the international bibliographic databanks SCIELO, HIGHWIRE, PUBMED, SCIRUS and LILACS to provide a useful and practical review for healthcare workers to make them aware of these microorganisms. Today, B. cepacia, P. aeruginosa and S. aureus are the most important infectious agents in cystic fibrosis patients. However, healthcare professionals must pay attention to emerging infectious agents in these patients, because they represent a potentially serious future problem. Therefore, these pathogens should be pointed out as a risk to these patients, and hospitals all over the world must be prepared to detect and combat these bacteria.

Exercise during childhood and adolescence: a prophylaxis against cystic fibrosis-related low bone mineral density? Exercise for bone health in children with cystic fibrosis

Inadequate bone mineral accrual during growth and accelerated bone demineralisation in adulthood are recognised as additional and serious complications for patients with cystic fibrosis (CF). However, little attention has been given to preventative strategies for this population. Inadequate bone accrual during childhood and adolescence, and premature bone loss, lead to a failure to attain an optimal peak bone mass, osteoporosis and fracture in patients with CF. Pharmaceutical treatments may assist in the improvement of bone in patients with CF, but these are usually not preferable for use in children. Evidence indicates that regular, weight-bearing exercise significantly enhances bone accrual in healthy children. This paper reviews the literature concerning the potential for weight-bearing exercise to improve bone mineral accrual in children with CF. All relevant literature since 1979 was obtained and reviewed from the Medline, PubMed, Cochrane and PEDro data base. Evidence concerning the efficacy of exercise for bone health in CF is lacking. There have been no controlled trials investigating the value of weight-bearing exercise for bone accrual in children with CF. As exercise may offer an effective and enjoyable strategy to improve the bone development in children who have CF, exercise should be a high priority for randomised controlled trials in this population.

A Review of the Research Literature on Evidence-Based Healthcare Design

Objective:

This report surveys and evaluates the scientific research on evidence-based healthcare design and extracts its implications for designing better and safer hospitals.

Background:

It builds on a literature review conducted by researchers in 2004.

Methods:

Research teams conducted a new and more exhaustive search for rigorous empirical studies that link the design of hospital physical environments with healthcare outcomes. The review followed a two-step process, including an extensive search for existing literature and a screening of each identified study for the relevance and quality of evidence.

Results:

This review found a growing body of rigorous studies to guide healthcare design, especially with respect to reducing the frequency of hospital-acquired infections. Results are organized according to three general types of outcomes: patient safety, other patient outcomes, and staff outcomes. The findings further support the importance of improving outcomes for a range of design characteristics or interventions, including single-bed rooms rather than multibed rooms, effective ventilation systems, a good acoustic environment, nature distractions and daylight, appropriate lighting, better ergonomic design, acuity-adaptable rooms, and improved floor layouts and work settings. Directions for future research are also identified.

Conclusions:

The state of knowledge of evidence-based healthcare design has grown rapidly in recent years. The evidence indicates that well-designed physical settings play an important role in making hospitals safer and more healing for patients, and better places for staff to work.

Infections in chronic lung diseases

Chronic lung diseases are prevalent worldwide and cause significant mortality and suffering. This article discusses infections that occur in three chronic lung diseases: chronic obstructive pulmonary disease, bronchiectasis, and cystic fibrosis. Rather than discussing the role of infections as etiology of these diseases, this article focuses on infections that occur in the background of established chronic lung disease.

Multidrug-resistant organisms in cystic fibrosis: management and infection-control issues

Chronic infection and inflammation are the hallmarks of cystic fibrosis lung disease. As cystic fibrosis patients are living longer owing to more intense treatment, multidrug-resistant organisms are being isolated increasingly from patients' respiratory tracts. While the adverse effects of Pseudomonas aeruginosa and Burkholderia cepacia complex are well described, less is known about the clinical significance of other emerging multidrug-resistant organisms, such as methicillin-resistant Staphylococcus aureus and Stenotrophomonas maltophilia. Owing to multiple mechanisms of antimicrobial resistance, these organisms are difficult to treat and often require combination antibiotic therapy. Until more is known about their pathogenicity and effect on clinical outcomes, physicians should be aware of the potential transmissibility of these organisms and implement adequate infection control strategies.

Neonatal screening for cystic fibrosis does not affect time to first infection with Pseudomonas aeruginosa

OBJECTIVE

Newborn screening for cystic fibrosis was introduced in the Piedmont region of Italy in the year 2000. Our aim with this study was to estimate the effect of newborn screening on the risk of Pseudomonas aeruginosa infection at the regional cystic fibrosis pediatric reference center.

METHODS

The time to first infection with P aeruginosa within the historical cohort of cystic fibrosis children diagnosed between January 1, 1997, and June 30, 2004, was investigated, comparing survival functions and the adjusted hazard ratio of children diagnosed before and after newborn screening introduction. The role of pancreatic insufficiency was also concurrently investigated.

RESULTS

Overall, 71 children diagnosed with cystic fibrosis were identified, 27 cases were clinically diagnosed before newborn screening introduction, and 5 of them presented with meconium ileus, whereas 44 were identified by newborn screening. Among them 35 needed pancreatic enzyme supplementation, whereas 34 children were infected with P aeruginosa. Both the nonparametric and semiparametric survival estimates failed to show any significant increase in the risk of P aeruginosa infection among screened children compared with historical controls. However, the median time from cystic fibrosis diagnosis to P aeruginosa infection among screened children was significantly shorter (183 vs 448 days). Children with impaired pancreatic function were at high risk of P aeruginosa infection.

CONCLUSIONS

The results of the study suggest that health authorities should regard newborn screening for cystic fibrosis as an opportunity to improve care and outcomes among affected children and shift the focus from whether it is appropriate to screen to how to optimize biomedical and psychosocial outcomes of screening.

Burkholderia cenocepacia utilizes ferritin as an iron source

Burkholderia cenocepacia is a member of the Burkholderia cepacia complex, a group of genetically similar species that inhabit a number of environmental niches, including the lungs of patients with cystic fibrosis (CF). To colonize the lung, this bacterium requires a source of iron to satisfy its nutritional requirements for this important metal. Because of the high potential for damage in lung tissue resulting from oxygen-iron interactions, this metal is sequestered by a number of mechanisms that render it potentially unavailable to invading micro-organisms. Such mechanisms include the intracellular and extracellular presence of the iron-binding protein ferritin. Ferritin has a highly stable macromolecular structure and may contain up to 4500 iron atoms per molecule. To date, there has been no known report of a pathogenic bacterial species that directly utilizes iron sequestered by this macromolecule. To examine the ability of ferritin to support growth of B. cenocepacia J2315, iron-deficient media were supplemented with different concentrations of ferritin and the growth kinetics characterized over a 40 h period. The results indicated that B. cenocepacia J2315 utilizes iron bound by ferritin. Further studies examining the mechanisms of iron uptake from ferritin indicated that iron utilization results from a proteolytic degradation of this otherwise stable macromolecular structure. Since it is known that the ferritin concentration is significantly higher in the CF lung than in healthy lungs, this novel iron-acquisition mechanism may contribute to infection by B. cenocepacia in people with CF.

Chronic colonization with Pandoraea apista in cystic fibrosis patients determined by repetitive-element-sequence PCR

Pandoraea apista is recovered with increasing frequency from the lungs of patients with cystic fibrosis (CF) and may represent an emerging pathogen (I. M. Jorgensen et al., Pediatr. Pulmonol. 36:439-446, 2003). We identified two CF patients from our hospital whose sputum specimens were culture positive for P. apista over the course of several years. Repetitive-element-sequence PCR was employed to determine whether sequential isolates that were recovered from these patients represented a single clone and whether each patient had been chronically colonized with the same strain. Banding patterns generated with ERIC primers, REP primers, and BOX primers showed that individual patient isolates had a high degree of similarity (>97%) and were considered identical. However, only the banding patterns from the ERIC primers and BOX primers were able to show that the strains from patients I and II were unique (similarity indices of 79.8% and 70.0%, respectively). We concluded that all strains of P. apista from patient I were identical, as were all strains from patient II, establishing chronic colonization. Only two of the three methods employed indicate that the strains from the two patients are distinct. This implied that the organism was not transferred from one patient to the other, suggesting that the choice of methodology could generate misleading results when examining person-to-person transmission regarding this organism.

Surveillance of cystic fibrosis patients with multi-drug resistant Gram-negative rods

OBJECTIVES

Although several nosocomial outbreaks with multi-drug resistant Gram-negative bacteria (MRGN) are documented, only few are known about the endemic situation of theses pathogens. Especially cystic fibrosis (CF) patients are known to be at risk for MRGN acquisition. We present surveillance data of endemic MRGN in CF patients from a German university hospital during a 3-year period.

METHODS

CF inpatients from 2002 to 2004 were included. A MRGN was defined as a Gram-negative rod of which less than two groups of antibiotics had been tested susceptible. MRGN patients who were admitted more than once were counted each time as a new MRGN case.

RESULTS

Three hundred and thirty-nine inpatient cases (109 different patients) with MRGN were enrolled. Two hundred and sixty-seven cases were known to be MRGN positive at the time point of admission, 167 cases were affected by pan-resistant pathogens. P. aeruginosa was the MRGN species detected most frequently. MRGN was detected after 48h of hospital stay in 9 patients.

CONCLUSIONS

MRGN surveillance is recommended by several experts but unfortunately only few data has been published. To our knowledge this is the first description of the complete endemic MRGN situation in CF patients. MRGN surveillance is necessary and will be continued in our facility.

Cystic fibrosis since 1938

Cystic fibrosis (CF) was distinguished from celiac disease in 1938. Then, it was a pathologic diagnosis, life expectancy was approximately 6 months, and the autosomal recessive disease was believed to arise from abnormal mucus plugging exocrine ducts. Death often occurred from lung infection. Discovery of the sweat electrolyte defect in 1953 and standardization of the sweat test in 1959 allowed identification of milder cases, and CF was no longer considered only a disorder of mucus. In 1955, establishment of centers with programs of aggressive, comprehensive care initiated striking improvement in longevity. The pillars of care established then (attention to nutrition, airway clearance, treatment of lung infection) remain today. In 1983, chloride transport was identified as the basic physiologic CF defect, accompanied by increased sodium reabsorption. In 1980, we learned that inflammation contributes independently to lung disease and constitutes an independent therapeutic target. In 1989, the discovery of the CF gene demonstrated the basic defect to be in a cAMP-regulated chloride channel. This afforded new diagnostic tests, opportunities for research, and prospects for using the gene as therapy. Since then, substantial advances in basic and clinical research catalyzed therapeutic improvements: median survival age now exceeds 30 years. The Cystic Fibrosis Foundation center network provides not only opportunity to conduct clinical trials but also means to disseminate new therapies. In the future, treatments directed at the basic defect can be expected, with concomitant improvements in morbidity and mortality.