Burkholderia Cepacia Complex Isolates Research Articles

Endophthalmitis caused by Burkholderia cepacia complex (BCC): clinical characteristics, antibiotic susceptibilities, and treatment outcomes

PurposeTo report the clinical characteristics, antibiotic susceptibilities, and review the literature of Burkholderia cepacia complex (BCC) associated endophthalmitis.Study designRetrospective, observational case series.MethodsClinical and microbiology records were reviewed for patients evaluated at the Bascom Palmer Eye Institute and diagnosed wisth culture-confirmed endophthalmitis due to BCC. Antibiotic susceptibility profiles were generated using standard microbiologic protocols via an automated VITEK system.ResultsEndophthalmitis associated with BCC was diagnosed in three patients. Infection occurred in the setting of post-penetrating keratoplasty (PKP), glaucoma filtering surgery, and suspected trauma. All isolates demonstrated in vitro susceptibility to ceftazidime and meropenem. Presenting visual acuity (VA) ranged from hand motion to light perception. Initial treatment strategies included intravitreal ceftazidime (2.25 mg/0.1 mL) and vancomycin (1.0 mg/0.1 mL) injections with fortified topical antibiotics in 2 patients, and surgical debridement of a corneoscleral melt with patch graft along with both topical fortified antibiotics oral antibiotics in the third patient. In all 3 patients, there was no VA improvement at last follow-up, as 2 eyes ultimately underwent enucleation and 1 eye exhibited phthisis bulbi at last follow-up. BCC related endophthalmitis was reviewed among 13 reports. Treatment outcomes were generally poor and antibiotic resistance was common. These BCC isolates cases demonstrated broad resistance patterns, with susceptibilities to ceftazidime (58%), ciprofloxacin (53%), and gentamicin (33%).ConclusionsEndophthalmitis caused by B. cepacia is a rare clinical entity with generally poor visual outcomes despite prompt treatment with appropriate antibiotics.

Clinicomicrobiological Profile and Antibiotic Susceptibility Pattern of Burkholderia cepacia Complex Isolates from a Tertiary Care Hospital in Southern India: A Cross-sectional Study

Introduction: Burkholderia cepacia Complex (BCC) is a group of Gram negative betaproteobacteria with complex taxonomy that causes healthcare-associated infections and hospital outbreaks. BCC is the fourth most pathogenic non fermentative Gram negative bacilli worldwide, following Burkholderia cepacia, Acinetobacter baumannii, and Stenotrophomonas maltophilia, with a prevalence ranging between 10-20% for non fermentative Gram negative bacilli and 5-15% for BCC. Human infections are caused by 22 known species and 14 novel species. Pulmonary BCC infections lead to “Cepacia syndrome,” a fatal illness that results in progressive respiratory failure and necrotising pneumonia, leading to early death in 20% of cases. Aim: To emphasise the disease burden and clinical outcomes of BCC infections, as well as to assess the performance of various methods for BCC detection. Materials and Methods: A cross-sectional study was conducted at PSG Institute of Medical Sciences and Research, Coimbatore, Tamil Nadu, India. A total of 91,778 samples were received between April 2021 and December 2022, over a period of one year and nine months, to determine the disease burden of BCC. The identification of BCC was carried out using manual culture and sensitivity, VITEK®-2 ID/AST system, Matrix Assisted Laser Desorption Ionisation-Time of Flight Mass Spectrometry (MALDIToF-MS), recA gene virulence determinant by Polymerase Chain Reaction (PCR), and 16S Ribosomal ribonucleic acid (rRNA) sequencing. Out of 115 manually identified BCC isolates, 56 (48.70%) underwent automated Vitek® 2 ID/AST, MALDI-ToF-MS, recA gene PCR, and 16S rRNA sequencing for identification and characterisation. The results were entered into Microsoft Excel, and statistical analysis was performed using the International Business Machines (IBM) Statistical Package for the Social Sciences (SPSS) software version 28.0. Results: Culture positivity was observed in 16,949 samples (18.47%), among which 3,387 (29.25%) were non fermentative gram negative bacilli. The incidence of Burkholderia spp. isolation was 115 (3.4%) out of 3,387 non fermentative gram negative bacilli. The prevalence of BCC among the study population was 115 (0.13%) out of 91,778. Conclusion: BCC, causing a wide array of infections, results in profound morbidity and mortality, especially in hospital settings. Early identification using Vitek-2 and MALDI-ToF-MS, along with molecular methods like PCR and 16S rRNA sequencing, could be the key to confirming the diagnosis and initiating appropriate management.

Clinical characteristics and outcomes of non-cystic fibrosis patients with Burkholderia cepacia complex bacteremia at a medical center in Taiwan.

Burkholderia cepacia complex (BCC) represents a group of multidrug-resistant gram-negative bacteria that cause infections among immunocompromised hosts. Bacteremia occurs in patients who are chronically ill and is associated with substantial morbidity and mortality. The aim of this study was to investigate the clinical characteristics and outcomes of BCC bacteremic patients without cystic fibrosis. We conducted a retrospective study at the National Taiwan University Hospital. Adults with BCC bacteremia from January 2015 to May 2019 were enrolled. The primary outcome was 14-day mortality. Multivariable logistic regression was performed for outcome analysis. One-hundred and ninety-five patients were analyzed and their mean age was 67 years. Over 95% of the BCC isolates were susceptible to trimethoprim/sulfomethoxazole (TMP/SXT). Levofloxacin resistance rates were high, with only 25.1% of isolates being susceptible. Pairwise comparisons were made between different definitive regimens including meropenem-monotherapy, ceftazidime-monotherapy, levofloxacin-monotherapy, TMP/SXT-monotherapy, tigecycline-monotherapy as well as combination versus monotherapy. No regimen was significantly associated with survival in our study. Multivariable logistic regression showed that the Pitt bacteremia score (adjust odds ratio [aOR],1.46; 95% confidence interval [CI],1.19-1.79; p<0.001), underlying metastatic cancer (aOR, 2.73; 95% CI, 1.01-7.39; p=0.047), inappropriate definitive treatment independently predicted greater 14-day mortality (aOR, 8.21; 95% CI, 2.49-27.08; p<0.001). No single regimen is associated with improved mortality. After adjusting for other potential confounders, our data suggest selection of an appropriate antibiotic provide better clinical outcomes among patients with BCC bacteremia.

Combined Clinical, Epidemiological, and Genome-Based Analysis Identified a Nationwide Outbreak of Burkholderia cepacia Complex Infections Caused by Contaminated Mouthwash Solutions.

BackgroundIn September 2018, Burkholderia cepacia complex (BCC) infections in 3 patients associated with exposure to a mouthwash solution (MWS) were reported to the Robert Koch Institute (RKI). As the product was still on the market and the scale of the outbreak was unclear, a nation-wide investigation was initiated.MethodsWe aimed to investigate BCC infections/colonizations associated with MWS. Hospitals, laboratories, and public health services were informed that BCC isolates should be sent to the RKI. These isolates were typed by pulsed-field gel electrophoresis (PFGE) and whole-genome sequencing (WGS) including development of an ad hoc core genome MLST (cgMLST) scheme.ResultsIn total, 36 patients from 6 hospitals met the case definition, the last patient in November 2018. Twenty-nine isolates from 26 of these patients were available for typing. WGS analysis revealed 2 distinct cgMLST clusters. Cluster 1 (Burkholderia arboris) contained isolates from patients and MWS obtained from 4 hospitals and isolates provided by the manufacturer. Patient and MWS isolates from another hospital were assigned to cluster 2 (B. cepacia).ConclusionsThe combined clinical, epidemiological, and microbiological investigation, including whole-genome analysis, allowed for uncovering a supraregional BCC outbreak in health care settings. Strains of B. arboris and B. cepacia were identified as contaminating species of MWS bottles and subsequent colonization and putative infection of patients in several hospitals. Despite a recall of the product by the manufacturer in August 2018, the outbreak lasted until December 2018. Reporting of contaminated medical products and recalls should be optimized to protect patients.

Clinical and Microbiological Profile of Patients with Bloodstream Infections Caused by Burkholderia cepacia Complex.

Introduction Burkholderia cepacia complex (BCC) is an emerging pathogen causing nosocomial bloodstream infections (BSIs), and its treatment is challenging due to its multidrug resistance. In India, there is a dearth of data on BSIs caused by BCC, therefore, an updated study is required to know the clinical and microbiological profile of these patients. We aimed to study the clinical epidemiology and antibiotic susceptibility pattern of BCC isolated from blood samples in our hospital. Materials and Methods This observational study was conducted from January 2019 to December 2020 at a tertiary care center in northern India. All the blood cultures were done on an automated blood culture system. All BCC isolates of BSI were identified depending on their morphological properties and biochemical reactions, and underwent the matrix-assisted laser desorption ionization time-of-flight mass spectrometry system to confirm diagnosis. Antibiotic susceptibility testing was done as per Clinical Laboratory and Standards Institute guidelines. Results BCC was isolated from 30 BSI patients over a 2-year period. Sixty-six percent (20/30) of patients had cancer and a majority of them were undergoing chemotherapy. The most common predisposing factors were the use of steroids, immunosuppressive drugs, and chemotherapy (93.3%), central lines (83.3%), use of higher antibiotics (60%), and diabetes mellitus type 2 (60%). The most common species isolated were B. cepacia (64%) and B. cenocepacia (30%). Isolates showed highest sensitivity to minocycline (100%), ceftazidime (73.3%), and meropenem (70%) and the least to ticarcillin–clavulanate. Conclusion BCC is an emerging pathogen causing BSIs, especially in malignancy patients. Minocycline can be a good choice for these bacteria.

1280. Minocycline Activity Against Acinetobacter baumannii-calcoaceticus Species Complex, Burkholderia Cepacia Complex, and Stenotrophomonas maltophilia from US Hospitals

1280. Minocycline Activity Against <i>Acinetobacter baumannii-calcoaceticus</i> Species Complex, Burkholderia Cepacia Complex, and <i>Stenotrophomonas maltophilia</i> from US Hospitals

Characterization of Burkholderia cepacia complex from environment influenced by human waste

ABSTRACT The natural environment is a primary source of infections caused by members of Burkholderia cepacia complex (BCC), but the release of human waste may in return enrich the natural environment with clinically relevant BCC. Seven BCC isolates from environment influenced by human liquid or solid waste across Croatia, and one clinical isolate was characterised. B. multivorans recovered from the soil at illegal dumpsite belonged to sequence type (ST)19; B. ambifaria from the agricultural soil fertilized with swine or poultry manure to ST927 or new ST; B. cenocepacia from creek sediment, river water and wound swab to new STs. Antimicrobial susceptibility of isolates ranged from sensitive to multidrug-resistant. A variety of bla TEM genes was confirmed in isolates. Isolates expressed the virulence factors and survived in river water during 50 days. The BCC present natural environments influenced by the human waste are of clinical relevance and a potential source of sporadic infections.

Comparison of Microbiological Characteristics and Genetic Diversity between Burkholderia cepacia Complex Isolates from Vascular Access and Other Clinical Infections.

Burkholderia cepacia complex (BCC) is a group of closely related bacteria with widespread environmental distribution. BCC bacteria are opportunistic pathogens that cause nosocomial infections in patients, especially cystic fibrosis (CF). Multilocus sequence typing (MLST) is used nowadays to differentiate species within the BCC complex. This study collected 41 BCC isolates from vascular access infections (VAIs) and other clinical infections between 2014 and 2020. We preliminarily identified bacterial isolates using standard biochemical procedures and further conducted recA gene sequencing and MLST for species identification. We determined genetic diversity indices using bioinformatics software. We studied 14 isolates retrieved from patients with VAIs and observed that Burkholderia cepacia was the predominant bacterial species, and B. contaminans followed by B. cenocepacia were mainly retrieved from patients with other infections. According to MLST data, we identified that all B. contaminans isolates belonged to ST102, while a wide variety of sequence types (STs) were found in B. cenocepacia isolates. In summary, the high diversity and easy transmission of BCC increase BCC infections, which provides insights into their potential clinical effects in non-CF infections.

Outbreak of Burkholderia cepacia Complex Due to Multiple Brands of Contaminated Aqueous Chlorhexidine in Hong Kong

Background: Contaminated chlorhexidine produced by a single company has been implicated in the outbreak or pseudo-outbreak of Burkholderia cepacia complex (BCC). However, simultaneous occurrence of multiple brands of contaminated chlorhexidine supplied by different manufacturers resulting in a persistent outbreak for &gt;1 year has not been well described. Objective: We report an outbreak of BCC with epidemiological investigation and using whole-genome sequencing (WGS) analysis of patient and environmental isolates in Hong Kong. Methods: Upon the investigation of a cohort of renal patients undergoing peritoneal dialysis colonized or infected with BCC in their exit sites, different brands of 0.05% aqueous chlorhexidine (aqCHX) used for exit site dressing, supplied from hospital or purchased from community pharmacies by patients, were cultured. A risk factor analysis for exit-site acquisition of BCC was performed. A site visit to a local manufacturer was conducted to investigate the process of production and to collect environmental samples for culture, which were further analyzed by WGS along with the BCC isolates cultured from patients and aqCHX purchased from community pharmacies. Results: Four patients undergoing peritoneal dialysis had cultures positive for BCC in the exit site swab in September 2019. A snapshot screening revealed 88 (32.0%) of 275 renal dialysis patients colonized with BCC. Of these patients, 47 (17.1%) were newly diagnosed and 41 (14.9%) were known to be colonized or infected with BCC according to retrospective data retrieval from January 1, 2018. A significantly greater proportion of patients with newly diagnosed BCC (cases) had used contaminated aqCHX for exit-site dressing than those with culture negative for BCC (controls): 38 of 47 (80.9%) versus 54 of 187 (28.9%) (P &lt; .001). Of 161 aqCHX samples, 10 brands from 4 manufacturers (purchased from community pharmacies), 125 (77.6%) were culture positive for BCC, whereas all 77 aqCHX samples supplied by the hospital, which are different brands and are produced by different manufacturers, were proven to be sterile. Of the 28 environmental samples taken from a local manufacturer during the site visit, 19 samples (67.9%, 3 collected from the instrument for production of aqCHX and all 16 newly produced aqCHX samples) were culture positive for BCC. WGS revealed 3 major clusters characterized by B. cenocepacia genomovar IIIA ST1547 and 2 novel MLST clusters from 52 patients and 26 environmental isolates selected. Conclusions: This outbreak was terminated by product recall, and the government has decided to take regulatory actions to ensure the sterility of antiseptics, including aqCHX.Funding: NoneDisclosures: None

Management and outcomes of Burkholderia cepacia complex bacteremia in patients without cystic fibrosis: a retrospective observational study.

Burkholderia cepacia complex (BCC) is an emerging pathogen of nosocomial infection in chronic or critically ill patients without cystic fibrosis (CF). The objective was to evaluate the management and outcomes of BCC bacteremia in patients without CF. We conducted a retrospective study of non-CF adult patients with BCC bacteremia between January 1997 and December 2016 at 4 tertiary hospitals in South Korea. A total of 216 non-CF patients with BCC bacteremia were identified. Most cases were hospital-acquired (79.2%), and the most common source was a central venous catheter (CVC) (42.1%). The rates of susceptibility to trimethoprim-sulfamethoxazole and piperacillin-tazobactam of BCC isolates were high as 92.8% and 90.3%, respectively. The rates of susceptibility to ceftazidime, meropenem, and levofloxacin were 75.5%, 72.3%, and 64.1%, respectively. The 14-day, 30-day, and in-hospital mortality rate was 19.4%, 23.1%, and 31.0%, respectively. Female (OR = 3.1; 95% CI, 1.4-6.8), liver cirrhosis (OR = 6.2; 95% CI, 1.6-16.6), septic shock (OR = 11.2; 95% CI, 5.1-24.8), and catheter-related infection (OR = 2.6, 95% CI, 1.2-5.8) were the independent risk factors for 30-day mortality. The outcome did not differ according to type of antibiotics used. Among 91 patients with CVC-related BCC bacteremia, delayed CVC removal (> 3days) had a higher rate of persistent bacteremia (54.5 vs. 26.1%; P = 0.03) and lower rate of clinical response (49.0 vs. 71.9%; P = 0.04), compared with early CVC removal (within 3days). BCC bacteremia occurring in non-CF patients was mostly hospital-acquired and CVC-related. Early removal of the catheter is crucial in treatment of CVC-related BCC bacteremia.

Investigation of Burkholderia cepacia complex bacteremia outbreak in a neonatal intensive care unit: a\xa0case series\xa0

IntroductionBurkholderia cepacia complex is a ubiquitous organism with a high virulence potential. It is found most commonly in moist environments. Hospital outbreaks have been reported from diverse sources such as contaminated faucets, nebulizers, disinfectant solutions, multidose antibiotic vials, tap water, bottled water, nasal sprays, and ultrasound gels. In this article, we present our experience in investigating and successfully managing an outbreak of nosocomial transmission of Burkholderia cepacia sepsis in the neonatal intensive care unit at SGT Hospital, Haryana, India.Case presentationDuring the month of March, multiple Burkholderia cepacia complex isolates were recovered from blood cultures of Caucasian babies admitted to the neonatal intensive care unit of our hospital. The organisms were multidrug-resistant, with in vitro sensitivity to meropenem alone (minimum inhibitory concentration = 4 μg/ml). An outbreak was suspected, and the neonatal intensive care unit in-charge and hospital infection control teams were alerted. Outbreak investigation was initiated, and surveillance samples were collected. Burkholderia cepacia complex was successfully isolated from suction apparatus. The isolates were phenotypically typed (biotyping and antimicrobial susceptibility testing) and found to be identical.ConclusionsIn our study, the index case might have been exposed to infection due to a physiological state of low immunity (preterm, low birth weight, and mechanical ventilation). The rest of the cases might have been exposed to this organism due to inadequate hand hygiene/improper cleaning and disinfection practices. Timely reporting and implementation of infection control measures played a significant role in curtailing this outbreak.

Evaluating the use of whole-genome sequencing for outbreak investigations in the lack of closely related reference genome

Whole-genome sequencing (WGS) has emerged as a powerful molecular typing method for outbreak analysis enabling the rapid discrimination between outbreak and non-outbreak isolates. However, such analysis can be challenging in the absence of closely related reference genomes. In this study, we assessed the use of WGS in investigating an outbreak of a relatively understudied bacterial pathogen with no publicly available closely related reference genome. Eleven Burkholderia cepacia complex (Bcc) isolates (seven from patients and four from disposable dermal gloves packages) that were collected during an outbreak were sequenced using the Illumina MiSeq platform. Our results showed that mapping the 11 sequenced Bcc outbreak isolates against a genetically distant reference genome yield loses coverage (31.6–48.3%) and a high number of detected false single-nucleotide polymorphisms (SNPs) (1123–2139). Therefore, a reference genome consensus from an outbreak clinical isolate was generated by combining both de novo assembly and mapping approaches. Based on this approach, we were able to demonstrate that the Bcc outbreak isolates were closely related and were phylogenetically distinct from the 11 publically available Bcc genomes. In addition, the pairwise SNP distance analysis detected only 1 to 6 SNPs differences among the outbreak isolates, confirming that contaminated disposable dermal gloves were the cause of the outbreak.

Clinical characteristics of bacteraemia caused by Burkholderia cepacia complex species and antimicrobial susceptibility of the isolates in a medical centre in Taiwan

This study investigated the clinical characteristics and outcomes of bacteraemia due to Burkholderia cepacia complex (BCC) species among 54 patients without cystic fibrosis from January 2013 to February 2015. BCC isolates were identified to the species level by the Bruker Biotyper MALDI-TOF MS system and by sequencing analysis of the 16S rRNA and recA genes. Antimicrobial susceptibilities of the isolates were determined by the agar dilution method. Sequencing of the recA gene in the 54 blood isolates revealed 37 (68.5%) isolates of B. cenocepacia, 9 (16.7%) of B. cepacia, 4 (7.4%) of B. multivorans and one isolate each of B. arboris, B. pseudomultivorans, B. seminalis, and B. vietnamiensis. The overall performance of the Bruker Biotyper MALDI-TOF MS system for correctly identifying the 54 BCC isolates to the species level was 79.6%, which was better than that (16.7%) by 16S RNA sequencing analysis. Bacteraemic pneumonia (n = 23, 42.6%) and catheter-related bacteraemia (n = 21, 38.9%) were the most common types of infection. Higher rates of ceftazidime and meropenem resistance were found in B. cepacia isolates (33.3% and 22.2%, respectively) than in isolates of B. cenocepacia (21.6% and 10.8%, respectively) and other species (12.5% and 12.5%, respectively). Overall, the 30-day mortality rate was 38.9% (21/54). Bacteraemia caused by BCC species other than B. cenocepacia and B. cepacia (adjusted odds ratio [aOR] 20.005, P = 0.024) and high SOFA score (aOR 1.412, P = 0.003) were predictive of higher 30–day mortality. Different BCC species are associated with different outcomes of bacteraemia and exhibit different susceptibility patterns.

Prevalence of Burkholderia species, including members of Burkholderia cepacia complex, among UK cystic and non-cystic fibrosis patients.

We aimed to establish the prevalence of different Burkholderia species among UK cystic fibrosis (CF) and non-CF patients over a 2 year period. Matrix-assisted laser desorption/ionization-time of flight mass spectrometry was used to identify isolates to genus level, followed by recA/gyrB sequence clustering or species-specific PCR. In all, 1047 Burkholderia isolates were submitted for identification from 361 CF patients and 112 non-CF patients, 25 from the hospital environment and three from a commercial company. Potential cross-infection was assessed by pulsed-field gel electrophoresis (PFGE) and multi- locus-sequence typing (MLST). MICs were determined for 161 Burkholderia cepacia complex (Bcc) isolates. CF Trust registry data were sought to examine clinical parameters relating to Bcc infection. Burkholderia multivorans was the most prevalent species among CF patients affecting 56 % (192) patients, followed by Burkholderia cenocepacia IIIA (15 %; 52 patients). Five novel recA clusters were found. Among non-CF patients, Burkholderia cepacia was the most prevalent species (37/112; 34 %), with 18 of 40 isolates part of a UK-wide B. cepacia 'cluster'. This and three other clusters were investigated by PFGE and MLST. Cable-pili positive isolates included two novel sequence types and representatives of ET12. Antibiotic susceptibility varied between and within species and CF/non- CF isolates. CF Trust registry data suggested no significant difference in lung function between patients harbouring B. cenocepacia, B. multivorans and other Bcc species (P=0.81). The dominance of B. multivorans in CF, the presence of a B. cepacia cluster among non-CF patients and the existence of putative novel species all highlighted the continuing role of Burkholderia species as opportunistic pathogens.

Accurate identification of members of the Burkholderia cepacia complex in cystic fibrosis sputum.

The Burkholderia cepacia complex (BCC) is a group of closely related species which includes opportunistic pathogens causing chronic respiratory infections in immunocompromised patients, or individuals affected by cystic fibrosis (CF). Other Burkholderia species causing infection in the CF population are Burkholderia gladioli and Burkholderia pseudomallei. Traditional phenotypic analyses have been demonstrated to be inadequate for reliable identifications of isolates of BCC and B.gladioli. A pan-genomic analysis approach was used to design species-specific probes for Burkholderia cenocepacia, B.cepacia, Burkholderia multivorans, Burkholderia vietnamiensis, Burkholderia ambifaria, Burkholderia dolosa, Burkholderia pyrrocinia and B.gladioli. Multiplex real-time PCR assay was developed and tested using sputum specimens collected from CF patients spiked with Burkholderia species. The assay exhibited 100% sensitivity for all eight target species and detected 10(2) to 10(3) CFUml(-1) when applied to spiked sputum. Our PCR assay resulted highly specific for each of the Burkholderia species tested, allowing discrimination among Burkholderia and non-Burkholderia pathogens. Analysis carried out on 200 sputa positive for the presence of Burkholderia revealed that PCR assay and recA sequencing were fully comparable for identification of Burkholderia at the level of species. Burkholderia cepacia complex (BCC) has a complex taxonomic organization and its identification is a challenge for microbiology laboratories. Nonidentification or misidentification of BCC isolates represent a problem in epidemiology and treatment of cystic fibrosis patients. The high specificity and sensitivity of the multiplex Real-time PCR assay developed in this study indicates its potential to be a rapid and reliable method for the detection of Burkholderia at the level of species from sputum samples of cystic fibrosis patients.

Polyclonal outbreak of bacteremia caused by Burkholderia cepacia complex and the presumptive role of ultrasound gel

A nosocomial polyclonal outbreak associated to bacteremia caused by different Burkholderia cepacia complex (BCC) species and clones is reported. Molecular characterization identified Burkholderia stabilis, Burkholderia contaminans, and Burkholderia ambifaria among BCC isolates obtained from patients in neonatal and adult intensive care units. BCC was also isolated from an intrinsically contaminated ultrasound gel, which constituted the presumptive BCC source. Prior BCC outbreak related to contaminated ultrasound gels have been described in the setting of transrectal prostate biopsy. Outbreak caused strains and/or clones of BCC have been reported, probably because BCC are commonly found in the natural environment; most BCC species are biofilm producers, and different species may contaminate an environmental source. The finding of multiple species or clones during the analysis of nosocomial BCC cases might not be enough to reject an outbreak from a common source.

92 Increasing virulence, acute phenotypic adaptations and evolving host–pathogen interactions during chronic Burkholderia cepacia complex infection of the cystic fibrosis lung

Objectives We aimed to define the phenotypic and genotypic adaptations that occur in the Burkholderia cepacia complex (BCC) during chronic infection of the cystic fibrosis (CF) lung. Methods We studied a total of 57 BCC isolates from 15 CF patients (2–6 isolates per patient), spanning infection periods ranging from 3 to 14 years. We assessed virulence using the Galleria mellonella model, and phenotypically characterized all isolates to determine how individual traits evolve during infection. Genome sequencing of selected early and late isolates provided insight into the genetic basis of the adaptations, whilst selected isolates were also studied in a murine infection model and in vitro macrophage model. Results Strikingly, during infection of 4 BCC-infected patients, the virulence of longitudinal isolates increased. Those patients were infected with either the B. cenocepacia ET-12 lineage (n = 3) or a B. multivorans outbreak strain (n = 1), both of which are linked with poor clinical outcome. Increasing virulence was uniformly correlated with increased haemolytic activity and decreased biofilm formation, consistent with the emergence of an ‘acute phenotype'. Late isolates displaying heightened virulence also exhibited altered host–pathogen interactions, with delayed clearance from Galleria and/or murine infection models, and reduced uptake by macrophages in vitro. Genome sequencing of isolates revealed evidence of convergent evolution, with comparable phenotypic adaptations arising through distinct genetic mutations. Conclusion BCC adaptation strategies within the CF lung differ from those observed in Pseudomonas aeruginosa , and may contribute to poor clinical outcome.

The contribution of antibiotic resistance mechanisms in clinical Burkholderia cepacia complex isolates: an emphasis on efflux pump activity.

Due to the limited information of the contribution of various antibiotic resistance mechanisms in clinical Burkholderia cepacia complex isolates, Antibiotic resistance mechanisms, including integron analysis, identification of quinolone resistance-determining region mutations, measurement of efflux pump activity, and sequence analysis of efflux pump regulators, were investigated in 66 clinical B. cepacia complex isolates. Species were identified via recA-RFLP and MALDI-TOF. Four genomovars were identified by recA-RFLP. B. cenocepacia (genomovar III) was the most prevalent genomovar (90.1%). Most isolates (60/66, 90.9%) were correctly identified by MALDI-TOF analysis. Clonal relatedness determined by PFGE analysis revealed 30 pulsotypes, including two major pulsotypes that comprised 22.7% and 18.2% of the isolates, respectively. Seventeen (25.8%) isolates harboured class 1 integron with various combinations of resistance genes. Among six levofloxacin-resistant isolates, five had single-base substitutions in the gyrA gene and three demonstrated efflux pump activities. Among the 42 isolates exhibiting resistance to at least one antimicrobial agent, 94.4% ceftazidime-resistant isolates (17/18) and 72.7% chloramphenicol-resistant isolates (16/22) demonstrated efflux pump activity. Quantitation of efflux pump RNA level and sequence analysis revealed that over-expression of the RND-3 efflux pump was attributable to specific mutations in the RND-3 efflux pump regulator gene. In conclusion, high-level expression of efflux pumps is prevalent in B. cepacia complex isolates. Mutations in the RND-3 efflux pump regulator gene are the major cause of efflux pump activity, resulting in the resistance to antibiotics in clinical B. cepacia complex isolates.

Clonal diversity among Burkholderia cepacia complex isolates from cystic fibrosis patients in a reference unit

IntroductionThe epidemiology of Burkholderia cepacia complex (Bcc) in cystic fibrosis (CF) is not widely known. MethodsAll CF patients with Bcc between 2002 and 2011 were reviewed, and a molecular analysis of isolates was performed. ResultsThe prevalence of Bcc infection was 7.2% (18/250). Molecular analysis of 16 Bcc isolates showed 5 species (7 B. contaminans, 6 B. cepacia, 1 B. cenocepacia, 1 B. multivorans, and 1 B. stabilis) and 13 sequence types. There were no cases of cross-transmission. ConclusionA high diversity of Bcc species was found in infected CF patients.

Multi-institutional outbreak of Burkholderia cepacia complex associated with contaminated mannitol solution prepared in compounding pharmacy

Burkholderia cepacia complex (BCC) has been described as a cause of nosocomial outbreaks. We describe an outbreak of and identify risk factors for nosocomial BCC infections associated with intrinsically contaminated mannitol 3% solution. Urinary and bloodstream infection caused by BCC were identified in hospitalized patients who underwent urologic surgery and received intraoperative irrigation of 3% mannitol solution in February 2009. The investigation included retrospective chart review, case control study, procedural review, and culture of mannitol solution. Seven BCC infections were identified. BCC isolates were recovered from blood and/or urine from patients and lots of mannitol in use during the outbreak period. Mannitol solution was produced by a compounding pharmacy. Receipt of larger volumes of contaminated solution was identified as a significant risk factor for infection (odds ratio, 1.5; P value < .05). BCC was also cultured in lots of mannitol in use in other hospitals. Manipulated mannitol solution is a potential source of infection. Contamination with paraben-degrading organisms can occur at the time of manufacture. Our findings suggest that contamination of mannitol at a compounding pharmacy occurred. Prompt communication to other hospitals and implementation of infection control measures were effective in avoiding further cases of infection.