Burkholderia cepacia complex in cystic fibrosis: critical gaps in diagnosis and therapy

Burkholderia cepacia complex (Bcc) is a bacterial group with 'natural' multi-antimicrobial resistance. This complex has generated epidemic outbreaks across the world. In people with cystic fibrosis (CF), Bcc can cause severe lung infections that lead to accelerated lung damage, which can be complicated by necrotizing pneumonia accompanied by high fevers, leucocytosis, and bacteraemia, which commonly causes fatal outcomes. Specifically, infection by Burkholderia cenocepacia is considered an exclusion criterion for lung transplantation. The species of Bcc exhibit both genetic and phenotypic hypervariability that complicate their accurate microbiological identification. Automated methods such as MALDI-TOF can err in the determination of species. Their slow growth even in selective agars and the absence of international consensuses on the optimal conditions for their isolation make early diagnosis a difficult challenge to overcome. The absence of correlations between antibiograms and clinical results has resulted in the absence of standardized cut-off values of antimicrobial susceptibility, a fact that brings a latent risk since incorrect antibiotic therapy can induce the selection of more aggressive variants that worsen the clinical picture of the host, added to the absence of a clear therapeutic guide for the eradication of pulmonary infections by Bcc in patients with CF, resulting in frequently ineffective treatments. There is an urgent need to standardize methods and diagnostic tools that would allow an early and accurate diagnosis, as well as to perform clinical studies of the effectiveness of available antibiotics to eradicate Bcc infections, which would allow us to establish standardized therapeutic schemes for Bcc-infected patients.

Mass Production of Arbuscular Mycorrhizal Fungi on the Sorghum Plants Inoculated with Burkholderia arboris Using Soybean Mill Waste and Vermicompost-Amended Soil-Sand Substrate

Arbuscular mycorrhizal (AM) fungi are being used as a new generation of biofertilizers to increase plant growth by improving plant nutrition and bio-protection. However, because of the obligatory nature of the plant host, large-scale multiplication of AM propagules is challenging, which limits its applicability. This study evaluates the ability of Burkholderia arboris to increase AM production in soybean mill waste and vermicompost amended by soil-sand mixture planted with sorghum as a host plant. The experiment was conducted in a nursery using a completely randomized design with four inoculation treatments (B. arboris, AM fungi, B. arboris + AM fungi, and control) under sterilized and unsterilized conditions. AM production was investigated microscopically (spore density and root colonization), and biochemically (AM-specific lipid biomarker, 16:1ω5cis derived from neutral lipid fatty acid (NLFA), and phospholipid fatty acid (PLFA) fractions from both soil and roots). Integrating B. arboris with AM fungi in organically amended pots was found to increase AM fungal production by 62.16 spores g-1 soil and root colonization by 80.85%. Biochemical parameters also increased with B. arboris inoculation: 5.49 nmol PLFA g-1 soil and 692.68 nmol PLFA g-1 root and 36.72 nmol NLFA g-1 soil and 3147.57 nmol NLFA g-1 root. Co-inoculation also increased glomalin-related soil protein and root biomass. Principal component analysis (PCA) further supported the higher contribution of B. arboris to AM fungi production under unsterilized conditions. In conclusion, inoculation of AM plant host seeds with B. arboris prior to sowing into organic potting mix could be a promising and cost-effective approach for increasing AM inoculum density for commercial production. Furthermore, efforts need to be made for up-scaling the AM production with different plant hosts and soil-substrate types.

The mechanism of action of auranofin analogs in B. cenocepacia revealed by chemogenomic profiling

Drug repurposing efforts led to the discovery of bactericidal activity in auranofin, a gold-containing drug used to treat rheumatoid arthritis. Auranofin kills Gram-positive bacteria by inhibiting thioredoxin reductase, an enzyme that scavenges reactive oxygen species (ROS). Despite the presence of thioredoxin reductase in Gram-negative bacteria, auranofin is not always active against them. It is not clear whether the lack of activity in several Gram-negative bacteria is due to the cell envelope barrier or the presence of other ROS protective enzymes such as glutathione reductase (GOR). We previously demonstrated that chemical analogs of auranofin (MS-40 and MS-40S), but not auranofin, are bactericidal against the Gram-negative Burkholderia cepacia complex. Here, we explore the targets of auranofin, MS-40, and MS-40S in Burkholderia cenocepacia and elucidate the mechanism of action of the auranofin analogs by a genome-wide, randomly barcoded transposon screen (BarSeq). Auranofin and its analogs inhibited the B. cenocepacia thioredoxin reductase and induced ROS but did not inhibit the bacterial GOR. Genome-wide, BarSeq analysis of cells exposed to MS-40 and MS-40S compared to the ROS inducers arsenic trioxide, diamide, hydrogen peroxide, and paraquat revealed common and unique mediators of drug susceptibility. Furthermore, deletions of gshA and gshB that encode enzymes in the glutathione biosynthetic pathway led to increased susceptibility to MS-40 and MS-40S. Overall, our data suggest that the auranofin analogs kill B. cenocepacia by inducing ROS through inhibition of thioredoxin reductase and that the glutathione system has a role in protecting B. cenocepacia against these ROS-inducing compounds.IMPORTANCEThe Burkholderia cepacia complex is a group of multidrug-resistant bacteria that can cause infections in the lungs of people with the autosomal recessive disease, cystic fibrosis. Specifically, the bacterium Burkholderia cenocepacia can cause severe infections, reducing lung function and leading to a devastating type of sepsis, cepacia syndrome. This bacterium currently does not have an accepted antibiotic treatment plan because of the wide range of antibiotic resistance. Here, we further the research on auranofin analogs as antimicrobials by finding the mechanism of action of these potent bactericidal compounds, using a powerful technique called BarSeq, to find the global response of the cell when exposed to an antimicrobial.

When is Burkholderia cepacia complex truly eradicated in adults with cystic fibrosis? A 20-year follow up study

BACKGROUND

Burkholderia cepacia complex (BCC) infection in cystic fibrosis (CF) is associated with increased morbidity and mortality. Current UK guidance recommends segregation of people with CF according to infection status. To date there is no universally agreed consensus on the number of negative samples or time interval since last isolation of BCC for eradication to be deemed successful.

METHODS

All cases of new BCC isolation at Manchester Adult Cystic Fibrosis Centre were followed-up between May 2002-May 2022. The number of subsequent positive and negative sputum samples for BCC were recorded, as well as eradication treatment received. Eradication was deemed successful if there were ≥3 negative sputum samples and no further positive sputum samples for the same species and strain ≥12 months until the end of follow-up.

RESULTS

Of 46 new BCC isolation, 25 were successfully eradicated and 21 resulted in chronic infection. 5 (16.7%) cases with exclusively negative sputum samples 6-12 months after initial isolation had subsequent samples that were culture-positive for BCC and 3 (10.7%) cases with exclusively negative sputum samples after 12-24 months had subsequent culture-positive samples. Cases where BCC was eradicated had a greater median number of days of eradication treatment (42, IQR 21-63) compared to those in whom BCC isolation resulted in chronic infection (28, IQR 14-42), p = 0.04.

CONCLUSIONS

A cautious approach to segregation should be maintained after new isolation of BCC in CF, as some individuals with ≥3 negative samples 12-24 months after initial isolation had subsequent sputum samples culture-positive for BCC.

In vitro and in vivo activity of cefiderocol against Achromobacter spp. and Burkholderia cepacia complex, including carbapenem-non-susceptible isolates

Achromobacter spp. and Burkholderia cepacia complex (Bcc) are rare but diverse opportunistic pathogens associated with serious infections, which are often multidrug resistant. This study compared the in vitro antibacterial activity of the siderophore antibiotic cefiderocol against Achromobacter spp. and Bcc isolates with that of other approved antibacterial drugs, including ceftazidime-avibactam, ciprofloxacin, colistin, imipenem-relebactam, and meropenem-vaborbactam. Isolates were collected in the SIDERO multinational surveillance program. Among 334 Achromobacter spp. isolates [76.6% from respiratory tract infections (RTIs)], cefiderocol had minimum inhibitory concentration (MIC)50/90 of 0.06/0.5 µg/mL overall and 0.5/4 µg/mL against 52 (15.6%) carbapenem-non-susceptible (Carb-NS) isolates. Eleven (3.3%) Achromobacter spp. isolates overall and 6 (11.5%) Carb-NS isolates were not susceptible to cefiderocol. Among 425 Bcc isolates (73.4% from RTIs), cefiderocol had MIC50/90 of ≤0.03/0.5 µg/mL overall and ≤0.03/1 µg/mL against 184 (43.3%) Carb-NS isolates. Twenty-two (5.2%) Bcc isolates overall and 13 (7.1%) Carb-NS isolates were not susceptible to cefiderocol. Cumulative MIC distributions showed cefiderocol to be the most active of the agents tested in vitro against both Achromobacter spp. and Bcc. In a neutropenic murine lung infection model and a humanized pharmacokinetic immunocompetent rat lung infection model, cefiderocol showed significant bactericidal activity against two meropenem-resistant Achromobacter xylosoxidans strains compared with untreated controls (P < 0.05) and vehicle-treated controls (P < 0.05), respectively. Meropenem, piperacillin-tazobactam, ceftazidime, and ciprofloxacin comparators showed no significant activity in these models. The results suggest that cefiderocol could be a possible treatment option for RTIs caused by Achromobacter spp. and Bcc.

Two consecutive outbreaks caused by chlorhexidine mouthwash contaminated with Burkholderia contaminans in a two-hospital tertiary care system

BACKGROUND

Hospital outbreaks caused by Burkholderia spp. have been linked to contamination of several medical solutions and products and are frequently associated with delayed detection and high mortality.

AIM

To describe the management of two consecutive Burkholderia contaminans outbreaks caused by contaminated mouthwash of different brands during the COVID-19 pandemic.

METHODS

This was a retrospective cohort study of all patients involved in two outbreaks caused by B. contaminans detected in 2021 and 2022. The investigation was initiated after a cluster of positive respiratory specimens, followed by retrospective and prospective case-finding.

FINDINGS

A total of 69 patients were affected, 47 in 2021 and 22 in 2022. The majority of affected patients had positive respiratory specimens (85.5%); 55.1% of cases had COVID-19, and 72.5% had multidrug-resistant organisms. Almost all (97.1%) patients required ventilation and 42.0% died. Seventeen percent of cases in the first outbreak were deemed to have been acquired by patient-to-patient transmission, whereas all of the cases in the second outbreak were infected directly from using mouthwash. The experience gained from the first outbreak and the formation of a multidisciplinary Infection Control Rapid Response Team resulted in more rapid recognition and control of the second outbreak. Multivariate analysis showed that older age, intensive care unit admission, and COVID-19 infection were independent predictors of mortality.

CONCLUSION

Burkholderia outbreaks at the time of COVID-19 were associated with high mortality. Rapid detection and response by a dedicated experienced team (as in the second outbreak) can reduce mortality and prevent superimposed cross-transmission between patients.

Examining the activity of cefepime-taniborbactam against Burkholderia cepacia complex and Burkholderia gladioli isolated from cystic fibrosis patients in the United States

The novel clinical-stage β-lactam-β-lactamase inhibitor combination, cefepime-taniborbactam, demonstrates promising activity toward many Gram-negative bacteria producing class A, B, C, and/or D β-lactamases. We tested this combination against a panel of 150 Burkholderia cepacia complex (Bcc) and Burkholderia gladioli strains. The addition of taniborbactam to cefepime shifted cefepime minimum inhibitory concentrations toward the provisionally susceptible range in 59% of the isolates tested. Therefore, cefepime-taniborbactam possessed similar activity as first-line agents, ceftazidime and trimethoprim-sulfamethoxazole, supporting further development.

Burkholderia cepacia complex as a cause of community acquired bacteremia in a young immuncompetent male

Burkholderia cepacia complex (BCC) is a well-recognized cause of nosocomial infections. We describe here a young healthy male who presented with fever and chest pain with ECG changes of acute pericarditis. Two sets of blood cultures at separate timings grew gram negative bacilli identified as BCC by molecular methods. The patient responded to intravenous ceftazidime despite high ceftazidime MIC's. The source of infection was probably contaminated nasal spray/nasal saline wash which he used after a balloon sinoplasty procedure one month ago. Issues related to accurate identification and susceptibility testing of BCC are also discussed.

Development of a qPCR detection approach for pathogenic Burkholderia cenocepacia associated with fresh vegetables

Natural environment serves as a reservoir for Burkholderia cepacia complex organisms, including the highly transmissible opportunistic human pathogen B. cenocepacia. Currently, there is a lack of an effective and quantitative method for B. cenocepacia detection in fresh food and other environmental niches. A quantitative real-time PCR (qPCR) detection method for B. cenocepacia bacteria was established in this study and validated using artificially inoculated fresh vegetable samples. Genome-wide comparative methods were applied to identify target regions for the design of species-specific primers. Assay specificity was measured with 12 strains of closely related Burkholderia bacteria and demonstrated the primer pair BCF6/R6 were 100% specific for detection of B. cenocepacia. The described qPCR assay evaluated B. cenocepacia with a 2 pg μl-1 limit of detection and appropriate linearity (R2 = 0.999). In 50 samples of experimentally infected produce (lettuce, onion, and celery), the assay could detect B. cenocepacia as low as 2.6 × 102 cells in each sample equal to 1 g. The established qPCR method quantitatively detects B. cenocepacia with high sensitivity and specificity, making it a promising technique for B. cenocepacia detection and epidemiological research on B. cepacia complex organisms from fresh vegetables.

Burkholderia cepacia infections at sites other than the respiratory tract: A large case series from a tertiary hospital in Madurai

Sparsely reported extrapulmonary Burkholderia cepacia complex (Bcc) infections highlights the importance of this study. This was a retrospective chart review of 37 patients with extrapulmonary Bcc infections admitted between December 2019 and July 2022 in a tertiary hospital. Males accounted for 70% of cases. 78% had atleast one underlying comorbid illness. Among 37 isolates, 22 were from blood, others include exudates, urine and peritoneal fluid. Susceptibility rates of ceftazidime, meropenem, minocycline, cotrimoxazole and levofloxacin were 88, 88, 70, 65.7 and 56.7% respectively. Eleven died of septic shock and 24 patients (64.8%) had good outcomes, while two were lost to followup.

Validation of a Rapid Microbiological Method for the Detection and Quantification of the Burkholderia cepacia Complex in an Antacid Oral Suspension

BACKGROUND

Despite the broad adoption of Soleris® technology in the food industry as semiquantitative method, it is almost completely unexplored in the pharmaceutical industry as a quantitative method for quantification of Burkholderia cepacia complex (Bcc).

OBJECTIVE

The efficacy of an automated growth-based system for a quantitative determination of the Bcc in an antacid oral suspension was studied. The main purpose of this validation study was to prove that the alternative method's entire performance is not inferior to the conventional method for a quantitative determination of Bcc.

METHOD

The antacid oral suspension's preservatives were neutralized, leading to the Burkholderia complex's recovery by means of the alternative method and the reference method. A calibration curve was generated for each strain by plotting DTs relative to the corresponding log CFU values. An equivalence of results was done through the construction of calibration curves that allowed the establishment of numerically equivalent results between the enumeration data from the reference method and the alternative method.

RESULTS

Thus following the guidelines of USP, essential validation parameters were shown, such as equivalence of results (CC >0.95), linearity (R2 >0.9025), accuracy (% recovery >70%), operating range, precision and ruggedness (DS <5 and CV <35%), specificity (inclusivity and exclusivity), limit of detection (LOD), and limit of quantification (LOQ).

CONCLUSIONS

It was shown that all the test results obtained from the alternative method were in statistical agreement with the standard method. Thus this new technology was found to meet all the validation criteria needed to be considered as an alternative method for the quantification of the Burkholderia complex in the antacid oral suspension tested.

HIGHLIGHTS

As outlined in USP chapter <1223> and demonstrated in this research the implementation of alternative methods can offer benefits in execution and automation while improving accuracy, sensitivity, and precision and can reduce the microbiological process time compared to the traditional ones.

An outbreak of Burkholderia contaminans at a quaternary children's hospital linked to equipment reprocessing

Burkholderia cepacia complex (BCC) has been increasingly implicated in local and multistate outbreaks in both adult and pediatric healthcare settings. However, a lack of source identification may be common for BCC outbreak investigations. We describe, in detail, the investigation of an outbreak of BCC (B. contaminans) among pediatric patients at a large quaternary-care children's hospital and our system-level changes and outcomes.

Post-transplant outcomes among cystic fibrosis patients undergoing lung transplantation colonized by Burkholderia: A single center cohort study

BACKGROUND

Prior infection with Burkholderia cepacia complex (BCC) has been associated with poorer outcomes after lung transplantation, posing an important dilemma for cystic fibrosis (CF). Although current guidelines consider BCC infection to be a relative contraindication, some centers continue to offer lung transplantation to BCC-infected CF patients.

METHODS

We conducted a retrospective cohort study which included all consecutive CF-LTR between 2000 and 2019 to compare the postoperative survival of BCC-infected CF lung transplant recipients (CF-LTR) to BCC-uninfected patients. We used a Kaplan-Meier analysis to compare survival of BCC-infected to BCC-uninfected CF-LTR and fitted a multivariable Cox model, adjusted for age, sex, BMI and year of transplantation as potential confounders. As an exploratory analysis, Kaplan-Meier curves were also stratified by the presence of BCC and urgency of transplantation.

RESULTS

A total of 205 patients were included with a mean age of 30.5 years. Seventeen patients (8%) were infected with BCC prior to LT. Patients were infected with the following species: B. multivorans5, B. vietnamiensis3, combined B. multivorans and B. vietnamiensis3 and others4. None of the patients were infected with B. cenocepacia. Three patients were infected with B. gladioli. One-year survival was 91.7% (188/205) for the entire cohort, 82.4% (14/17) among BCC-infected CF-LTR, and 92.5% (173/188) among BCC uninfected CF-LTR (crude HR = 2.19; 95%CI 0.99-4.85; p = 0.05). In the multivariable model, presence of BCC was not significantly associated with worse survival (adjusted HR 1.89; 95%CI 0.85-4.24; p = 0.12). In the stratified analysis for both presence of BCC and urgency of transplantation, urgency of transplantation among BCC-infected CF-LTR appeared to be associated with poorer outcome (p = 0.003 across the 4 subgroups).

CONCLUSION

Our results suggest that non-cenocepacia BCC-infected CF-LTR have comparable survival rate to BCC-uninfected CF-LTR.

Design, Development, and Validation of a Culture-Independent Nucleic Acid Diagnostics Method for the Rapid Detection and Quantification of the Burkholderia cepacia Complex in Water with an Equivalence to ISO/TS 12869:2019

In the wake of a series of outbreaks of finished pharmaceutical product-related Burkholderia cepacia complex (Bcc) human infections worldwide, the United States Food and Drug Administration (FDA) in 2017, and subsequently in 2021, issued advisory notifications to the pharmaceutical industry for stringent Bcc testing requirements for pharmaceutical manufacturing processes and for finished pharmaceutical products prior to release to the marketplace. The advisory notifications highlight non-sterile aqueous finished pharmaceutical products as being a major culprit associated with many of these human infection events. As such, there has been a significant number of Bcc-contaminated finished product recalls resulting in company revenue losses, delayed finished product release, finished product shortages for patients, and manufacturing plant shutdowns coupled with company reputational damage. With many of the finished product recall events, pharmaceutical grade water and/or manufacturing facility water distribution systems were identified as the primary origin source of Bcc contamination. Testing and monitoring regimes currently employed to identify Bcc contamination of water associated with pharmaceutical manufacturing are often limited by costly, laborious, lengthy, and nonspecific traditional microbial culture-based methodologies. Presently FDA approved, European Conformity (CE) marked, and International Organization for Standardization (ISO) standard microbial culture-independent rapid, quantitative, specific, and sensitive nucleic acid diagnostics (NAD) methodologies are now gaining greater widespread acceptance in their routine usage in testing laboratories. Here we present the development of a rapid (<4 hours from sample in to result out) single test culture-independent Bcc NAD method, incorporating a quantitative real-time polymerase chain reaction (qPCR) assay. This method can be used for the detection and simultaneous identification of all 24 Bcc species currently assigned, directly from water samples. This culture-independent Bcc NAD method is validated to the testing method equivalent of the ISO/TS 12869:2019 standard, which is a widely used rapid culture-independent NAD method for detecting Gram-negative Legionella species in water.

Synergistic Interactions among Burkholderia cepacia Complex-Targeting Phages Reveal a Novel Therapeutic Role for Lysogenization-Capable Phages

Antimicrobial resistance is a danger to global public health and threatens many aspects of modern medicine. Bacterial species such as those of the Burkholderia cepacia complex (Bcc) cause life-threatening respiratory infections and are highly resistant to antibiotics. One promising alternative being explored to combat Bcc infections is phage therapy (PT): the use of phages to treat bacterial infections. Unfortunately, the utility of PT against many pathogenic species is limited by its prevailing paradigm: that only obligately lytic phages should be used therapeutically. It is thought that 'lysogenic' phages do not lyse all bacteria and can transfer antimicrobial resistance or virulence factors to their hosts. We argue that the tendency of a lysogenization-capable (LC) phage to form stable lysogens is not predicated exclusively on its ability to do so, and that the therapeutic suitability of a phage must be evaluated on a case-by-case basis. Concordantly, we developed several novel metrics-Efficiency of Phage Activity, Growth Reduction Coefficient, and Stable Lysogenization Frequency-and used them to evaluate eight Bcc-specific phages. Although these parameters vary considerably among Bcc phages, a strong inverse correlation (R2 = 0.67; P < 0.0001) exists between lysogen formation and antibacterial activity, indicating that certain LC phages with low frequency of stable lysogenization may be therapeutically efficacious. Moreover, we show that many LC Bcc phages interact synergistically with other phages in the first reported instance of mathematically defined polyphage synergy, and that these interactions result in the eradication of in vitro bacterial growth. Together, these findings reveal a novel therapeutic role for LC phages and challenge the current paradigm of PT. IMPORTANCE The spread of antimicrobial resistance is an imminent threat to public health around the world. Particularly concerning are species of the Burkholderia cepacia complex (Bcc), which cause life-threatening respiratory infections and are notoriously resistant to antibiotics. Phage therapy is a promising alternative being explored to combat Bcc infections and antimicrobial resistance in general, but its utility against many pathogenic species, including the Bcc, is restricted by the currently prevailing paradigm of exclusively using rare obligately lytic phages due to the perception that 'lysogenic' phages are therapeutically unsuitable. Our findings show that many lysogenization-capable phages exhibit powerful in vitro antibacterial activity both alone and through mathematically defined synergistic interactions with other phages, demonstrating a novel therapeutic role for LC phages and therefore challenging the currently prevailing paradigm of PT.

Phage therapy in a lung transplant recipient with cystic fibrosis infected with multidrug-resistant Burkholderia multivorans

BACKGROUND

There is increased interest in bacteriophage (phage) therapy to treat infections caused by antibiotic-resistant bacteria. A lung transplant recipient with cystic fibrosis and Burkholderia multivorans infection was treated with inhaled phage therapy for 7 days before she died.

METHODS

Phages were given via nebulization through the mechanical ventilation circuit. Remnant respiratory specimens and serum were collected. We quantified phage and bacterial deoxyribonucleic acid (DNA) using quantitative polymerase chain reaction, and tested phage neutralization in the presence of patient serum. We performed whole genome sequencing and antibiotic and phage susceptibility testing on 15 B. multivorans isolates. Finally, we extracted lipopolysaccharide (LPS) from two isolates and visualized their LPS using gel electrophoresis.

RESULTS

Phage therapy was temporally followed by a temporary improvement in leukocytosis and hemodynamics, followed by worsening leukocytosis on day 5, deterioration on day 7, and death on day 8. We detected phage DNA in respiratory samples after 6 days of nebulized phage therapy. Bacterial DNA in respiratory samples decreased over time, and no serum neutralization was detected. Isolates collected between 2001 and 2020 were closely related but differed in their antibiotic and phage susceptibility profiles. Early isolates were not susceptible to the phage used for therapy, while later isolates, including two isolates collected during phage therapy, were susceptible. Susceptibility to the phage used for therapy was correlated with differences in O-antigen profiles of an early versus a late isolate.

CONCLUSIONS

This case of clinical failure of nebulized phage therapy highlights the limitations, unknowns, and challenges of phage therapy for resistant infections.

Contrasting treatment responses by Burkholderia cepacia complex-related deep pyoderma: a series of two cases

Background:

The Burkholderia cepacia complex (Bcc) is an opportunistic pathogen in humans and animals. Deep pyoderma caused by these bacteria in dogs has been previously reported. This case series aims to describe contrasting treatment responses in Bcc-related deep pyoderma in two dogs, a male and a female.

Case Description:

Both patients had a history of immune-mediated polyarthritis (IMPA) managed with oral ciclosporin and prednisolone. Their skin lesions were multifocal, irregular, erythematous to hemorrhagic, alopecic papules, plaques, and nodules, with extensive crusting, draining tracts, and ulceration. Cytological findings revealed a marked inflammatory response consisting of non-degenerative and degenerative neutrophils and macrophages, with moderate to abundant intracellular and extracellular Bcc. Ciclosporin and prednisolone were stopped in case 2 after diagnosis. However, it was challenging to stop the regimen in case 1 because of the recurrence of IMPA and the onset of iatrogenic hypoadrenocorticism. Case 1 did not achieve remission for approximately 66 weeks even with seven protocols because of multiple relapses, whereas it took only 3 weeks to achieve remission in case 2 while using one drug.

Conclusion:

For deep pyoderma with extensive lesions in immunosuppressed patients, one should consider infection with Bcc. Therefore, immunosuppressants should promptly be reduced in such patients, and then, intensive antimicrobial therapy may achieve remission.

Invasive Burkholderia cepacia Complex Infections among Persons Who Inject Drugs, Hong Kong, China, 2016-2019

During March 2016–January 2019, Burkholderia cepacia complex (BCC) infection developed in 13 persons who inject drugs (PWID) in Kowloon West Region, Hong Kong, China. Seven cases were infective spondylitis, 2 endocarditis, 2 septic arthritis, 1 intramuscular abscess and bacteremia, and 1 necrotizing fasciitis. Pulsed-field gel electrophoresis revealed that the isolates from 9 patients were clonally related. This clone caused major illness, and 11 of the 13 patients required surgical treatment. Clinicians should be aware of this pathogen and the appropriate broad-spectrum antimicrobial drugs to empirically prescribe for PWID with this life-threatening infection. Close collaboration among public health authorities, outreach social workers, and methadone clinics is essential for timely prevention and control of outbreaks in the PWID population.

Liver Cirrhosis Complicated by Spontaneous Bacterial Peritonitis Caused by the Burkholderia cepacia Complex

A 79-year-old man with underlying alcoholic liver cirrhosis presented with complaints of a fever, abdominal pain, and difficulty walking. A diagnostic work-up revealed liver atrophy and chylous ascites, and spontaneous bacterial peritonitis (SBP) was diagnosed based on the cell and neutrophil counts. The Burkholderia cepacia complex (Bcc) was detected on blood and ascitic fluid cultures. Although broad-spectrum antibiotic therapy was initiated, the infection was difficult to control, and the patient died of multiple organ failure. Bcc is often multidrug-resistant and difficult to treat. SBP caused by Bcc has been rarely reported and may have a serious course, thus necessitating caution.

Minocycline Activity against Unusual Clinically Significant Gram-Negative Pathogens

The minocycline susceptibility of 3,856 isolates including Burkholderia, Achromobacter, Alcaligenes, Aeromonas, and Stenotrophomonas maltophilia from the SENTRY surveillance (2014 to 2019) were analyzed. The susceptibilities of these species (%S) were Achromobacter spp. (n = 411; 92.6%), Burkholderia cepacia species complex (n = 199; 85.9%), Aeromonas spp. (n = 127; 99.2%), Chryseobacterium spp. (n = 59; 94.9%), Alcaligenes faecalis (n = 42; 88.1%), and S. maltophilia (n = 2,287; 99.5%). These data suggest that minocycline is a useful treatment option for infections caused by unusual Gram-negative pathogens.

New benzo(a)pyrene-degrading strains of the Burkholderia cepacia complex prospected from activated sludge in a petrochemical wastewater treatment plant

The prospection of bacteria that are resistant to polyaromatic hydrocarbons (PAH) of activated sludge from a Petrochemical Wastewater Treatment Plant (WWTP) allows investigating potential biodegraders of PAH. For this purpose, sludge samples were cultured with benzo(a)pyrene and/or naphthalene as carbon sources. The recovered isolates were characterized by biochemical methods and identified based on the analysis of the sequence of three genes: 16S, recA and gyrB. The isolated strains were shown to be capable of producing surfactants, which are important for compound degradation. The ability to reduce benzo(a)pyrene in vitro was tested by gas chromatography. After 20 days of experiment, the consortium that was enriched with 1 mg/L of benzo(a)pyrene was able to reduce 30% of the compound when compared to a control without bacteria. The four isolated strains that significantly reduced benzo(a)pyrene belong to the Burkholderia cepacia complex and were identified within the consortium as the species B. cenocepacia IIIa, B. vietnamiensis, B. cepacia, and B. multivorans. This finding demonstrates the biotechnological potential of the B. cepacia complex strains for use in wastewater treatment and bioremediation. Previous studies on hydrocarbon-degrading strains focused mainly on contaminated soil or marine areas. In this work, the strains were prospected from activated sludge in a WWTP and showed the potential of indigenous samples to be used in both improving treatment systems and bioremediation of areas contaminated with petrochemical waste.

Unwanted Feedback: Malaria Antibodies Hinder Vaccine Boosting

Whole-organism vaccination is a promising approach to prevent malaria. In this issue of Cell Host & Microbe, McNamara and colleagues identify epitope masking as a hindrance to antibody boosting after repeated administration of attenuated Plasmodium falciparum sporozoite vaccine.

Antibiotic treatment for Burkholderia cepacia complex in people with cystic fibrosis experiencing a pulmonary exacerbation

BACKGROUND

Chronic pulmonary infection is a hallmark of lung disease in cystic fibrosis. Infections dominated by organisms of the Burkholderia cepacia complex, a group of at least 18 closely-related species of gram-negative bacteria, are particularly difficult to treat. These infections may be associated with a fulminant necrotising pneumonia. Burkholderia cepacia complex bacteria are resistant to many common antibiotics and able to acquire resistance against many more. Following patient segregation in cystic fibrosis medical care, the more virulent epidemic strains are not as frequent, and new infections are more likely to be with less virulent environmentally-acquired strains. Although evidence-based guidelines exist for treating respiratory exacerbations involving Pseudomonas aeruginosa, these cannot be extended to Burkholderia cepacia complex infections. This review, which is an update of a previous review, aims to assess the available trial evidence for the choice and application of treatments for these infections.

OBJECTIVES

To assess the effectiveness and safety of different antibiotic regimens in people with cystic fibrosis experiencing an exacerbation and chronically infected with organisms of the Burkholderia cepacia complex.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched the reference lists of relevant articles and reviews. Date of latest search: 29 May 2019.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials of treatments for exacerbations of pulmonary symptoms in people with cystic fibrosis chronically infected with organisms of the Burkholderia cepacia complex.

DATA COLLECTION AND ANALYSIS

No relevant trials were identified.

MAIN RESULTS

No trials were included in this review.

AUTHORS' CONCLUSIONS

Burkholderia cepacia complex infections present a significant challenge for people with cystic fibrosis and their clinicians. The incidence is likely to increase as the cystic fibrosis population ages; and managing and treating these infections will become more important. There is a lack of trial evidence to guide decision making and no conclusions can be drawn from this review about the optimal antibiotic regimens for people with cystic fibrosis who have chronic Burkholderia cepacia complex infections. Clinicians must continue to assess each person individually, taking into account in vitro antibiotic susceptibility data, previous clinical responses and their own experience. Multicentre randomised clinical trials are needed to assess the effectiveness of different antibiotic regimens in people with cystic fibrosis infected with organisms of the Burkholderia cepacia complex.

Antibiotic therapy for chronic infection with Burkholderia cepacia complex in people with cystic fibrosis

BACKGROUND

Cystic fibrosis (CF) a life-limiting inherited disease affecting a number of organs, but classically associated with chronic lung infection and progressive loss of lung function. Chronic infection by Burkholderia cepacia complex (BCC) is associated with increased morbidity and mortality and therefore represents a significant challenge to clinicians treating people with CF. This review examines the current evidence for long-term antibiotic therapy in people with CF and chronic BCC infection.

OBJECTIVES

The objective of this review is to assess the effects of long-term oral and inhaled antibiotic therapy targeted against chronic BCC lung infections in people with CF. The primary objective is to assess the efficacy of treatments in terms of improvements in lung function and reductions in exacerbation rate. Secondary objectives include quantifying adverse events, mortality and changes in quality of life associated with treatment.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched online trial registries and the reference lists of relevant articles and reviews.Date of last search: 29 May 2019.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of long-term antibiotic therapy in people with CF and chronic BCC infection.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data, assessed risk of bias and assessed the quality of the evidence using GRADE.

MAIN RESULTS

We included one RCT (100 participants) which lasted 52 weeks comparing continuous inhaled aztreonam lysine (AZLI) and placebo in a double-blind RCT for 24 weeks, followed by a 24-week open-label extension and a four-week follow-up period. The average participant age was 26.3 years, 61% were male and average lung function was 56.5% predicted.Treatment with AZLI for 24 weeks was not associated with improvement in forced expiratory volume in one second (FEV₁), mean difference 0.91% (95% confidence interval (CI) -3.15 to 4.97) (moderate-quality evidence). The median time to the next exacerbation was 75 days in the AZLI group compared to 51 days in the placebo group, but the difference was not significant (P = 0.27) (moderate-quality evidence). Similarly, the number of participants hospitalised for respiratory exacerbations showed no difference between groups, risk ratio (RR) 0.88 (95% CI 0.53 to 1.45) (moderate-quality evidence). Overall adverse events were similar between groups, RR 1.08 (95% CI 0.98 to 1.19) (moderate-quality evidence). There were no significant differences between treatment groups in relation to mortality (moderate-quality evidence), quality of life or sputum density.In relation to methodological quality, the overall risk of bias in the study was assessed to be unclear to low risk.

AUTHORS' CONCLUSIONS

We found insufficient evidence from the literature to determine an effective strategy for antibiotic therapy for treating chronic BCC infection.

Eradication therapy for Burkholderia cepacia complex in people with cystic fibrosis

BACKGROUND

Chronic infection with Burkholderia cepacia complex species remains a significant problem for clinicians treating people with cystic fibrosis. Colonisation with Burkholderia cepacia complex species is linked to a more rapid decline in lung function and increases morbidity and mortality. There remain no objective guidelines for strategies to eradicate Burkholderia cepacia complex in cystic fibrosis lung disease, as these are inherently resistant to the majority of antibiotics and there has been very little research in this area. This review aims to examine the current treatment options for people with cystic fibrosis with acute infection with Burkholderia cepacia complex and to identify an evidence-based strategy that is both safe and effective. This is an updated version of the review.

OBJECTIVES

To identify whether treatment of Burkholderia cepacia complex infections can achieve eradication, or if treatment can prevent or delay the onset of chronic infection. To establish whether following eradication, clinical outcomes are improved and if there are any adverse effects.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched the reference lists of relevant articles and reviews.Last search: 12 March 2019.We also searched electronic clinical trials registers for the USA and Europe.Date of last search: 12 March 2019.

SELECTION CRITERIA

Randomised or quasi-randomised studies in people with cystic fibrosis of antibiotics or alternative therapeutic agents used alone or in combination, using any method of delivery and any treatment duration, to eradicate Burkholderia cepacia complex infections compared to another antibiotic, placebo or no treatment.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed for inclusion in the review the eligibility of 52 studies (79 references) identified by the search of the Group's Trial Register and the other electronic searches.

MAIN RESULTS

No studies looking at the eradication of Burkholderia cepacia complex species were identified.

AUTHORS' CONCLUSIONS

The authors have concluded that there was an extreme lack of evidence in this area of treatment management for people with cystic fibrosis. Without further comprehensive studies, it is difficult to draw conclusions about a safe and effective management strategy for Burkholderia cepacia complex eradication in cystic fibrosis. Thus, while the review could not offer clinicians evidence of an effective eradication protocol for Burkholderia cepacia complex, it has highlighted an urgent need for exploration and research in this area, specifically the need for well-designed multi-centre randomised controlled studies of a variety of (novel) antibiotic agents.

Burkholderia cepacia complex outbreaks among non-cystic fibrosis patients in the intensive care units: A review of adult and pediatric literature

Burkholderia cepacia complex (Bcc) is a Gram-negative bacterium commonly found in moist environments and soil. Bcc species are associated with many outbreaks in intensive care units (ICUs). In this review, we describe the sources of Bcc outbreaks among non-cystic fibrosis (CF) patients in various ICUs that include neonatal intensive care units, pediatric intensive care units and adult ICUs. Also we summarize the risk factors and outcome predictors of Bcc infection or colonization in non-CF critically ill patients. Finally, we describe the infection control measures that are used to manage and prevent the spread of Bcc outbreaks. PubMed was searched from 1 January 1994 and 31 December 2017. We found 30 outbreaks of Bcc among non-cystic fibrosis patients in ICUs; 17 outbreaks occurred in adult ICUs. The source was identified in 22 outbreaks. B. cepacia was the most common Bcc species causing outbreaks in ICUs; it was detected in 21 outbreaks. Indwelling central lines, presence of renal failure on hemodialysis, multiple bronchoscopic procedures, and recent abdominal surgery are independently associated with the development of B. cepacia bacteremia, while prolonged duration on a mechanical ventilator, a large number of nebulized albuterol therapies delivered, and prescription of beta-lactam, aztreonam, or macrolide-vancomycin antibiotics are risk factors for respiratory tract acquisition of B. cepacia. Disease severity and age were the main significant independent predictors of 14-day mortality in adult ventilated non-CF patients with Bcc acquisition. Bcc species have been linked to many outbreaks in non-CF patients in ICUs. Strict application of infection control standards is critical to limit the emergence and spread of Bcc in ICU settings.

Eradication therapy for Burkholderia cepacia complex in people with cystic fibrosis

BACKGROUND

Chronic infection with Burkholderia cepacia complex species remains a significant problem for clinicians treating people with cystic fibrosis. Colonisation with Burkholderia cepacia complex species is linked to a more rapid decline in lung function and increases morbidity and mortality. There remain no objective guidelines for strategies to eradicate Burkholderia cepacia complex in cystic fibrosis lung disease, as these are inherently resistant to the majority of antibiotics and there has been very little research in this area. This review aims to examine the current treatment options for people with cystic fibrosis with acute of Burkholderia cepacia complex and to identify an evidence-based strategy that is both safe and effective. This is an updated version of the review.

OBJECTIVES

To identify whether treatment of Burkholderia cepacia complex infections can achieve eradication, or if treatment can prevent or delay the onset of chronic infection. To establish whether following eradication, clinical outcomes are improved and if there are any adverse effects.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched the reference lists of relevant articles and reviews.Last search: 14 July 2016.We also searched electronic clinical trials registers for the USA and Europe.Date of last search: 14 July 2016.

SELECTION CRITERIA

Randomised or quasi-randomised studies in people with cystic fibrosis of antibiotics or alternative therapeutic agents used alone or in combination, using any method of delivery and any treatment duration, to eradicate Burkholderia cepacia complex infections compared to another antibiotic, placebo or no treatment.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed for inclusion in the review the eligibility of 50 studies (70 references) identified by the search of the Group's Trial Register and the other electronic searches.

MAIN RESULTS

No studies looking at the eradication of Burkholderia cepacia complex species were identified.

AUTHORS' CONCLUSIONS

The authors have concluded that there was an extreme lack of evidence in this area of treatment management for people with cystic fibrosis. Without further comprehensive studies, it is difficult to draw conclusions about a safe and effective management strategy for Burkholderia cepacia complex eradication in cystic fibrosis. Thus, while the review could not offer clinicians evidence of an effective eradication protocol for Burkholderia cepacia complex, it has highlighted an urgent need for exploration and research in this area, specifically the need for well-designed multi-centre randomised controlled studies of a variety of (novel) antibiotic agents.

Antibiotic treatment for Burkholderia cepacia complex in people with cystic fibrosis experiencing a pulmonary exacerbation

BACKGROUND

Chronic pulmonary infection is a hallmark of lung disease in cystic fibrosis. Infections dominated by organisms of the Burkholderia cepacia complex, a group of at least 18 closely-related species of gram-negative bacteria, are particularly difficult to treat. These infections may be associated with a fulminant necrotising pneumonia. Burkholderia cepacia complex bacteria are resistant to many common antibiotics and able to acquire resistance against many more. Following patient segregation in cystic fibrosis medical care, the more virulent epidemic strains are not as frequent, and new infections are more likely to be with less virulent environmentally-acquired strains. Although evidence-based guidelines exist for treating respiratory exacerbations involving Pseudomonas aeruginosa, these cannot be extended to Burkholderia cepacia complex infections. This review, which is an update of a previous review, aims to assess the available trial evidence for the choice and application of treatments for these infections.

OBJECTIVES

To assess the effectiveness and safety of different antibiotic regimens in people with cystic fibrosis experiencing an exacerbation and chronically infected with organisms of the Burkholderia cepacia complex.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched the reference lists of relevant articles and reviews.Date of latest search: 28 August 2015.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials of treatments for exacerbations of pulmonary symptoms in people with cystic fibrosis chronically infected with organisms of the Burkholderia cepacia complex.

DATA COLLECTION AND ANALYSIS

No relevant trials were identified.

MAIN RESULTS

No trials were included in this review.

AUTHORS' CONCLUSIONS

Burkholderia cepacia complex infections present a significant challenge for people with cystic fibrosis and their clinicians. The incidence is likely to increase as the cystic fibrosis population ages; and managing and treating these infections will become more important. There is a lack of trial evidence to guide decision making and no conclusions can be drawn from this review about the optimal antibiotic regimens for people with cystic fibrosis who have chronic Burkholderia cepacia complex infections. Clinicians must continue to assess each person individually, taking into account in vitro antibiotic susceptibility data, previous clinical responses and their own experience. Multicentre randomised clinical trials are needed to assess the effectiveness of different antibiotic regimens in people with cystic fibrosis infected with organisms of the Burkholderia cepacia complex.

Eradication therapy for Burkholderia cepacia complex in people with cystic fibrosis

BACKGROUND

Chronic infection with Burkholderia cepacia complex species remains a significant problem for clinicians treating people with cystic fibrosis. Colonisation with Burkholderia cepacia complex species is linked to a more rapid decline in lung function and increases morbidity and mortality. There remain no objective guidelines for strategies to eradicate Burkholderia cepacia complex in cystic fibrosis lung disease, as these are inherently resistant to the majority of antibiotics and there has been very little research in this area. This review aims to examine the current treatment options for people with cystic fibrosis with acute of Burkholderia cepacia complex and to identify an evidence-based strategy that is both safe and effective.

OBJECTIVES

To identify whether treatment of Burkholderia cepacia complex infections can achieve eradication, or if treatment can prevent or delay the onset of chronic infection. To establish whether following eradication, clinical outcomes are improved and if there are any adverse effects.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched the reference lists of relevant articles and reviews.Last search: 13 January 2014.We also searched electronic clinical trials registers for the USA and Europe.Date of last search: 28 November 2013.

SELECTION CRITERIA

Randomised or quasi-randomised studies in people with cystic fibrosis of antibiotics used alone or in combination, using any method of delivery and any treatment duration, to eradicate Burkholderia cepacia complex infections compared to another antibiotic, placebo or no treatment.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed for inclusion in the review the eligibility of 43 studies (61 references) identified by the search of the Group's Trial Register and the other electronic searches.

MAIN RESULTS

No studies looking at the eradication of Burkholderia cepacia complex species were identified.

AUTHORS' CONCLUSIONS

The authors have concluded that there was an extreme lack of evidence in this area of treatment management for people with cystic fibrosis. Without further comprehensive studies, it is difficult to draw conclusions about a safe and effective management strategy for Burkholderia cepacia complex eradication in cystic fibrosis. Thus, while the review could not offer clinicians evidence of an effective eradication protocol for Burkholderia cepacia complex, it has highlighted an urgent need for exploration and research in this area, specifically the need for well-designed multi-centre randomised controlled studies of a variety of (novel) antibiotic agents.

Antibiotic treatment for Burkholderia cepacia complex in people with cystic fibrosis experiencing a pulmonary exacerbation

BACKGROUND

Chronic pulmonary infection is one of the hallmarks of lung disease in cystic fibrosis. Infections dominated by organisms of the Burkholderia cepacia complex, a group of at least 17 closely-related species of gram-negative bacteria, are particularly difficult to treat. These infections may be associated with a fulminant necrotising pneumonia, and are greatly feared by patients. Burkholderia cepacia bacteria are innately resistant to many common antibiotics and able to acquire resistance against many more. Since strict patient segregation was introduced to cystic fibrosis medical care, the incidence of the more virulent epidemic strains has fallen, and new infections are more likely to be with environmentally-acquired strains which seem to exhibit less virulence. Nonetheless, exacerbations of respiratory symptoms require effective therapy directed against the dominant bacterial species. Although evidence-based guidelines exist for the treatment of respiratory exacerbations involving Pseudomonas aeruginosa, the most common chronic infection in cystic fibrosis, these cannot be directly extended to Burkholderia cepacia complex infections. The aim of this review is to assess the available trial evidence for choice and application of treatments for Burkholderia cepacia complex infections.

OBJECTIVES

To assess the effectiveness and safety of different antibiotic regimens in people with cystic fibrosis experiencing an exacerbation, who are chronically infected with organisms of the Burkholderia cepacia complex.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched the reference lists of relevant articles and reviews.Date of latest search: 29 November 2011.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials of treatments for exacerbations of pulmonary symptoms in cystic fibrosis patients chronically infected with organisms of the Burkholderia cepacia complex.

DATA COLLECTION AND ANALYSIS

No relevant trials were identified.

MAIN RESULTS

No trials were included in this review.

AUTHORS' CONCLUSIONS

Burkholderia cepacia complex infections present a significant challenge for cystic fibrosis clinicians and patients alike. The incidence is likely to increase as the cystic fibrosis population ages and the problem of how to manage and treat these infections becomes more important. There is a lack of trial evidence to guide decision making and no conclusions can be drawn from this review about the optimal antibiotic regimens for cystic fibrosis patients with chronic Burkholderia cepacia complex infections. Clinicians must continue to assess each patient individually, taking into account in vitro antibiotic susceptibility data, previous clinical responses and their own experience. There is a clear need for multi-centre randomised clinical trials to assess the effectiveness of different antibiotic regimens in cystic fibrosis patients infected with organisms of the Burkholderia cepacia complex.

Burkholderia cepacia complex infection in a case of sinonasal polyposis recurrence without cystic fibrosis

Burkholderia cepacia complex (BCC) has been rarely isolated in infections of the ear, nose and throat region in immunocompetent patients without cystic fibrosis. There is only one previous study in literature that reported BCC isolation in immunocompetent patients with sinonasal polyposis. We describe herein a rare case of multiresistant sinonasal infection by BCC in an immunocompetent patient with recurrent sinonasal polyposis. BCC seems to be a potentially emerging bacterial pathogen of sinonasal structures in patients with polyposis, also after FESS.

Emerging and Unusual Gram-Negative Infections in Cystic Fibrosis

People with cystic fibrosis (CF) have chronic airway infection and frequent exposure to antibiotics, which often leads to the emergence of resistant organisms. In addition to the development of multiresistance in common CF pathogens such as Pseudomonas aeruginosa, several newer, inherently resistant gram-negative species are becoming more common, including Burkholderia cepacia complex, Stenotrophomonas maltophilia, Achromobacter (Alcaligenes) xylosoxidans, certain Ralstonia species, and those within the new genus Pandoraea. Many of these are closely related and have similar phenotypes, making accurate laboratory identification challenging. Although their role in contributing to pulmonary disease in CF is not clear, some, such as those of the B. cepacia complex, are clearly linked to an adverse prognosis, and both treatment and infection control issues can pose a real challenge.

Isolation measures for prevention of infection with respiratory pathogens in cystic fibrosis: a systematic review

Respiratory infections are the most important cause of morbidity and mortality in patients with cystic fibrosis (CF). These infections are typically caused by a limited number of respiratory pathogens, particularly Burkholderia cepacia complex (BCC) and Pseudomonas aeruginosa (PA). Since the 1980s, several outbreaks of unique strains of PA and BCC among CF patients attending the same CF care centres have been described, leading to a sharp decline in the patients' health. One of the measures adopted in CF centres to interrupt ongoing outbreaks is the separation of patients with a respiratory tract culture that is positive for PA or BCC from patients who are not infected. This type of measure has been implemented routinely in many CF centres to prevent cross-transmission of PA and BCC. The aim of this review was to determine what evidence is available to support the efficacy of isolation (or segregation) practices in preventing, delaying or reducing the risk for CF patients of acquiring PA and BCC. A systematic review of scientific literature from 1980 to 31 December 2004 was performed. Existing guidelines regarding infection control in CF were also analysed. In total, 398 relevant papers were retrieved. Only 10 well-designed studies were found that evaluated the efficacy of isolation practices in preventing the transmission of respiratory pathogens in CF care centres (one prospective controlled study, one retrospective cohort study, five 'before-after' studies and three cross-sectional studies. No systematic reviews or randomized controlled trials exist on this subject. In the absence of studies with an experimental, controlled design, the efficacy of isolation practices in preventing the transmission of respiratory pathogens in CF remains unproven. However, notwithstanding the considerable limits represented by the study designs, which were mainly retrospective, the observational studies reviewed seem to support the implementation of isolation (or segregation) measures to reduce the risk of transmission of BCC and PA in CF patients.

Combination aerosol therapy to treat Burkholderia cepacia complex

Burkholderia cepacia infection in cystic fibrosis (CF) patients is associated with significant morbidity and mortality, yet no definitive treatment is currently available. This report describes a new approach to treat B. cepacia infection in CF patients, using a combination of amiloride and tobramycin aerosols. Four adults with the typical clinical syndrome of CF were recruited after repeated positive sputum cultures for B. cepacia. Aerosols of amiloride and tobramycin were given three times daily for 1-6 months, and repeated sputum cultures were collected to assess efficacy. Three of the four patients treated with the combined therapy eradicated B. cepacia from their sputum cultures for at least 2 yrs, and there were no adverse events. This novel combination may provide a new therapeutic option for Burkholderia cepacia infections. Furthermore, the strategy of combining antibiotics with ion transport agents may have ramifications for the treatment of other multi-resistant organisms.

Burkholderia cenocepacia and Burkholderia multivorans: influence on survival in cystic fibrosis

INTRODUCTION

Burkholderia cepacia infection has been associated with a poor prognosis for patients with cystic fibrosis (CF). It is now recognised that organisms classified as B cepacia comprise a number of distinct genomic species each known as a genomovar of the B cepacia complex (BCC). The outcome of infection for CF patients with individual genomovars is unknown. The clinical outcome of infection with the two most commonly isolated genomovars (B cenocepacia and B multivorans) was studied at a specialist CF centre between 1982 and 2003.

METHODS

The numbers of patients who progressed from initial to chronic infection were assessed. Control groups were created by matching patients with chronic BCC infection by percentage forced expiratory volume in 1 second with patients with Pseudomonas aeruginosa infection. Outcome measures were survival time, deaths from "cepacia syndrome", rate of decline in spirometry and body mass index (BMI), and treatment requirements.

RESULTS

Forty nine patients had an initial infection with either B multivorans (n = 16) or B cenocepacia (n = 33); 8/16 and 31/33, respectively, developed chronic infection (p<0.001). Deaths from "cepacia syndrome" occurred in both BCC groups. Patients with B cenocepacia infection had a shorter survival than patients with P aeruginosa infection (p = 0.01). There was no difference in survival between CF patients infected with B multivorans and P aeruginosa. There were no observed differences in changes in spirometry and BMI or treatment requirements between the BCC groups and respective controls.

CONCLUSION

In CF, the genomovar status of BCC may influence both the likelihood of progression from initial to chronic infection and the overall survival of the patients.

The impact of pan-resistant bacterial pathogens on survival after lung transplantation in cystic fibrosis: results from a single large referral centre

Reported actuarial one-year survival for patients with cystic fibrosis (CF) after lung transplant is 55-91%. Infection is the most common cause of early death. Colonization with Burkholderia cepacia complex is associated with reduced survival and international lung transplant referral guidelines support individual unit assessment policies for patients colonized with other pan-resistant bacteria. We examined local data on survival after transplant for CF to determine the impact of colonization with pan-resistant bacteria. A retrospective review of all CF patients from Royal Prince Alfred Hospital (RPAH), Sydney, who underwent lung transplantation at St Vincent's Hospital, Sydney, 1989-2002, was performed. Sixty-five patients were listed for lung transplantation with 54 (male: female=29:25) receiving transplants. Of the 11 patients (17%) who died on the waiting list, six were colonized with pan-resistant Pseudomonas aeruginosa. Thirty of the 54 transplanted patients had at least one pan-resistant organism before transplant. In 28 this included P. aeruginosa. Overall one-year survival was 92% with a median survival of 67 months. Overall survival for the pan-resistant group (N = 30) was not significantly different to survival in those with sensitive organisms (N = 24) (Logrank chi square = 1.6, P = 0.2). Three patients colonized with B. cepacia complex pre-transplant survive at 11, 40 and 60 months post-transplant. Infection contributed to 11 of the 18 post-transplant deaths, with pre-transplant-acquired bacterial pathogens responsible in two cases. Patients continued to acquire multiresistant bacteria post-transplantation. Lung transplant survival at St Vincent's Hospital for CF adults from RPAH compares favourably with international benchmarks. Importantly, colonization with pan-resistant bacteria pre-transplant did not appear to adversely affect survival post-transplant.

Pulmonary transplantation for cystic fibrosis: pre-transplant recipient characteristics in patients dying of peri-operative sepsis

BACKGROUND

Pulmonary transplantation has emerged as a successful treatment for end-stage cystic fibrosis. Despite the chronic bronchial sepsis and often multi-resistant organisms seen in this group of recipients, death due to post-operative sepsis is relatively scarce. Identifying potential recipient risk factors for poor outcome may further improve the utilization of a scarce donor pool.

METHODS

We assessed the role of pre-operative clinical measures of sepsis, microbial characteristics and recipient characteristics on post-transplant outcome in 85 cystic fibrosis patients who underwent pulmonary transplantation. Ten percent of patients died in the early post-operative period due to sepsis. The prognostic role of recipient factors including markers of sepsis, such as white cells and C-reactive protein (CRP), and the influence of multi-resistant organisms, in particular organisms from the Burkholderia cepacia complex, on outcomes were investigated.

RESULTS

We found no prognostic effect of gender, pre-transplant CRP, forced expiratory volume in 1 second (FEV(1)), weight, diabetic status or infection with multi-resistant Pseudomonas organisms. A raised white cell count or temperature or a pre-transplant infection with B cepacia was, however, associated with a significantly poorer prognosis at p = 0.03, 0.03 and 0.001, respectively.

CONCLUSIONS

Pre-operative B cepacia complex infection, leukocytosis and pyrexia, but not CRP, weight, diabetes or lung function, were found to be associated with poorer post-transplant outcome. The most clinically relevant of these to the subsequent risk of post-operative death from sepsis appear to be B cepacia infection and pyrexia.