Should Antimicrobial Resistance Limit Access to an Organ Transplant?

Burkholderia cenocepacia (B cenocepacia) is a gram-negative bacteria associated with significant morbidity and mortality following lung transplantation. Most US transplant programs consider B cenocepacia colonization to be an absolute contraindication to transplantation. This article argues that, if clinicians have good clinical reasons to expect poor outcomes for patients with B cenocepacia, then offering transplantation anyway is an abrogation of clinicians' fiduciary duties. This article also discusses other fiduciary obligations transplant programs might have to patients with B cenocepacia, such as referring to another transplant center, considering novel treatment options, and investigating how the infection's virulence factors stratify that patient's risk for poor transplant outcomes.

Burkholderia thailandensis Isolated from Infected Wound, Southwest China, 2022.

We report a clinical isolate of Burkholderia thailandensis 2022DZh obtained from a patient with an infected wound in southwest China. Genomic analysis indicates that this isolate clusters with B. thailandensis BPM, a human isolate from Chongqing, China. We recommend enhancing monitoring and surveillance for B. thailandensis infection in both humans and livestock.

Harnessing the Diversity of Burkholderia spp. Prophages for Therapeutic Potential.

Burkholderia spp. are often resistant to antibiotics, and infections with these organisms are difficult to treat. A potential alternative treatment for Burkholderia spp. infections is bacteriophage (phage) therapy; however, it can be difficult to locate phages that target these bacteria. Prophages incorporated into the bacterial genome have been identified within Burkholderia spp. and may represent a source of useful phages for therapy. Here, we investigate whether prophages within Burkholderia spp. clinical isolates can kill conspecific and heterospecific isolates. Thirty-two Burkholderia spp. isolates were induced for prophage release, and harvested phages were tested for lytic activity against the same 32 isolates. Temperate phages were passaged and their host ranges were determined, resulting in four unique phages of prophage origin that showed different ranges of lytic activity. We also analyzed the prophage content of 35 Burkholderia spp. clinical isolate genomes and identified several prophages present in the genomes of multiple isolates of the same species. Finally, we observed that Burkholdera cenocepacia isolates were more phage-susceptible than Burkholderia multivorans isolates. Overall, our findings suggest that prophages present within Burkholderia spp. genomes are a potentially useful starting point for the isolation and development of novel phages for use in phage therapy.

Challenges and mitigation strategies associated with Burkholderia cepacia complex contamination in pharmaceutical manufacturing.

Burkholderia cepacia complex (BCC) is a Gram-negative, non-spore-forming bacterium with more than 20 opportunistic pathogenic species, most commonly found in soil and water. Due to their rapid mutation rates, these organisms are adaptable and possess high genomic plasticity. BCC can cause life-threatening infections in immunocompromised individuals, such as those with cystic fibrosis, chronic granulomatous disease, and neonates. BCC contamination is a significant concern in pharmaceutical manufacturing, frequently causing non-sterile product recalls. BCC has been found in purified water, cosmetics, household items, and even ultrasound gel used in veterinary practices. Pharmaceuticals, personal care products, and cleaning solutions have been implicated in numerous outbreaks worldwide, highlighting the risks associated with intrinsic manufacturing site contamination. Regulatory compliance, product safety, and human health protection depend on testing for BCC in pharmaceutical manufacturing. Identification challenges exist, with BCC often misidentified as other bacteria like non-lactose fermenting Escherichia coli or Pseudomonas spp., particularly in developing countries where reporting BCC in pharmaceuticals remains limited. This review comprehensively aims to address the organisms causing BCC contamination, genetic diversity, identification challenges, regulatory requirements, and mitigation strategies. Recommendations are proposed to aid pharmaceutical chemists in managing BCC-associated risks and implementing prevention strategies within manufacturing processes.

Genomic editing in Burkholderia multivorans by CRISPR/Cas9.

Burkholderia cepacia complex bacteria have emerged as opportunistic pathogens in patients with cystic fibrosis and immunocompromised individuals, causing life-threatening infections. Because of the relevance of these microorganisms, genetic manipulation is crucial for explaining the genetic mechanisms leading to pathogenesis. Despite the availability of allelic exchange tools to obtain unmarked gene deletions in Burkholderia, these require a step of merodiploid formation and another of merodiploid resolution through two independent homologous recombination events, making the procedure long-lasting. The CRISPR/Cas9-based system could ease this constraint, as only one step is needed for allelic exchange. Here, we report the modification of a two-plasmid system (pCasPA and pACRISPR) for genome editing in Burkholderia multivorans. Several modifications were implemented, including selection marker replacement, the optimization of araB promoter induction for the expression of Cas9 and λ-Red system encoding genes, and the establishment of plasmid curing procedures based on the sacB gene or growth at a sub-optimal temperature of 18°C-20°C with serial passages. We have shown the efficiency of this CRISPR/Cas9 method in the precise and unmarked deletion of different genes (rpfR, bceF, cepR, and bcsB) from two strains of B. multivorans, as well as its usefulness in the targeted insertion of the gfp gene encoding the green fluorescence protein into a precise genome location. As pCasPA was successfully introduced in other Burkholderia cepacia complex species, this study opens up the possibility of using CRISPR/Cas9-based systems as efficient tools for genome editing in these species, allowing faster and more cost-effective genetic manipulation.IMPORTANCEBurkholderia encompasses different species of bacteria, some of them pathogenic to animals and plants, but others are beneficial by promoting plant growth through symbiosis or as biocontrol agents. Among these species, Burkholderia multivorans, a member of the Burkholderia cepacia complex, is one of the predominant species infecting the lungs of cystic fibrosis patients, often causing respiratory chronic infections that are very difficult to eradicate. Since the B. multivorans species is understudied, we have developed a genetic tool based on the CRISPR/Cas9 system to delete genes efficiently from the genomes of these strains. We could also insert foreign genes that can be precisely placed in a chosen genomic region. This method, faster than other conventional strategies based on allelic exchange, will have a major contribution to understanding the virulence mechanisms in B. multivorans, but it can likely be extended to other Burkholderia species.

Diving deep for the needle in the haystack: An outbreak investigation of Burkholderia cenocepacia bacteremia.

In an Indian oncology setting, between August and December 2021, 56 patients, developed Burkholderia cenocepacia bacteremia. An investigation revealed a contaminated batch of the antiemetic drug palonosetron. The outbreak was terminated by withdrawing the culprit batch and the findings were reported promptly to regulatory authorities.

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.

Efficacy of Antibiotic Bone Cement in the Treatment of Burkholderia cepacia Infection After Spinal Internal Fixation Surgery: Case Report and Literature Review.

BACKGROUND: In recent years, the number of spinal internal fixation operations has increased significantly, correlating with an elevated risk of postoperative surgical site infection and a rising incidence rate. While the conventional treatment approach involves surgical debridement combined with antibiotic administration, there is a notable gap in reported strategies for Burkholderia cepacia infection and patients exhibiting multidrug resistance. METHODS: Surgical site infection occurred in a patient following internal fixation surgery for thoracic vertebral fractures. Despite the application of systemic antibiotics and regular dressing changes, no improvement was observed. Bacterial culture and drug sensitivity experiments revealed a multidrug-resistant Burkholderia cepacia infection. Two comprehensive debridement procedures were performed along with continuous post-operative irrigation combined with antibiotic administration; however, no significant improvement was observed. The patient's infection was significantly controlled following treatment with vancomycin loaded bone cement. RESULTS: Following spinal internal fixation surgery, the management of a B. cepacian infection with multidrug resistance presented a significant challenge, despite the application of debridement procedures and systemic antibiotics. In this case, after 20 days of treatment with vancomycin-loaded bone cement, the patient's C-reactive protein level decreased to 54 mg/L, was normalized by February, and normal levels were maintained in the surgical area 1 month and 6 months after bone cement removal. CONCLUSIONS: The use of vancomycin-loaded bone cement proves effective in treating postoperative B. cepacian infection in a multidrug-resistant case following spinal internal fixation surgery.

Unique Presentations of Burkholderia gladioli Infections in Several Strains of Immunocompromised Mice.

Four strains of experimentally naïve mice (NOD. Cg-Prkdc scid Il2rg tm1Wjl /SzJ [NSG], NOD. Cg- Rag1 tm1Mom Il2rg tm1Wjl /SzJ [NRG], B6.129S(Cg)-Stat1 tm1Dlv/J [STAT1 -/-], and B6.129S7- Ifngr1 tm1Agt/J[IFNγR -/-] housed in a barrier facility developed unusual and seemingly unrelated clinical signs. Young NSG/NRG mice (n = 49, mean age = 4 ± 0.4 mo) exhibited nonspecific clinical signs of moderate-to-severe lethargy, hunched posture, decreased body condition, and pallor. In contrast to the NSG/NRG mice, the STAT1-/- and IFNγ R-/- mice (n = 5) developed large subcutaneous abscesses on the head and neck. These mice were euthanized, and samples were collected for culture. NSG/NRG mice had moderate-markedly enlarged livers (20 of 49, 40%) and spleens (17 of 49, 35%). The livers contained multiple, variably-sized, tan regions throughout all lobes. Histology revealed necrotizing hepatitis (13 of 17, 77%), splenic and hepatic extramedullary hematopoiesis (17 of 17, 100%), glomerular histiocytosis (6 of 17, 35%), and metritis (6 of 11, 55%) with perivascular inflammation, suggesting hematogenous spread Differentials for these lesions included mouse hepatitis virus, ectromelia virus, Pseudomonas aeruginosa, Salmonella spp., and Clostridium piliforme. Burkholderia gladioli was cultured from liver lesions and subcutaneous abscesses and confirmed with 16S ribosomal RNA sequencing. After completing systematic testing of the environment, failure of the water autoclave cycle was suspected as the cause of the outbreak. To address the situation, individually ventilated racks were sanitized and new breeders were purchased; these actions dramatically reduced B. gladioli infections. The current literature contains few reports of B. gladioli infections in immunocompromised mice, and its typical presentation is torticollis and rolling. B. gladioli infection is a potential differential for subcutaneous abscesses, hepatitis, and splenomegaly in immunocompromised mice. Careful monitoring of sterilization techniques is essential to prevent such infections in a barrier facility.

Phage Milagro: a platform for engineering a broad host range virulent phage for Burkholderia.

IMPORTANCE: Burkholderia infections are a significant concern in people with CF and other immunocompromising disorders, and are difficult to treat with conventional antibiotics due to their inherent drug resistance. Bacteriophages, or bacterial viruses, are now seen as a potential alternative therapy for these infections, but most of the naturally occurring phages are temperate and have narrow host ranges, which limit their utility as therapeutics. Here we describe the temperate Burkholderia phage Milagro and our efforts to engineer this phage into a potential therapeutic by expanding the phage host range and selecting for phage mutants that are strictly virulent. This approach may be used to generate new therapeutic agents for treating intractable infections in CF patients.

Acidic pH modulates Burkholderia cenocepacia antimicrobial susceptibility in the cystic fibrosis nutritional environment.

IMPORTANCE: Burkholderia cenocepacia causes severe infections in cystic fibrosis (CF) patients. CF patients are prone to reoccurring infections due to the accumulation of mucus in their lungs, where bacteria can adhere and grow. Some of the antibiotics that inhibit B. cenocepacia in the laboratory are not effective for CF patients. A major contributor to poor clinical outcomes is that antibiotic testing in laboratories occurs under conditions that are different from those of sputum. CF sputum may be acidic and have increased concentrations of iron and zinc. Here, we used a medium that mimics CF sputum and found that acidic pH decreased the activity of many of the antibiotics used against B. cenocepacia. In addition, we assessed susceptibility to more than 500 antibiotics and found four active compounds against B. cenocepacia. Our findings give a better understanding of the lack of a relationship between susceptibility testing and the clinical outcome when treating B. cenocepacia infections.

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.

Outbreak investigation of NDM-producing Burkholderia cepacia causing neonatal sepsis in Pakistan.

Aim: To investigate the outbreak of Burkholderia cepacia complex (BCC), mortality, antimicrobial resistance and associated risk factors in the neonatal intensive care unit. Method: Eighteen blood culture samples from neonates and twenty swab samples from different neonatal intensive care unit surfaces were collected. The VITEK 2 was used to confirm the isolates and generate the antibiogram. PCR was used to identify blaNDM. Results: Eighteen samples tested positive for BCC, and 10/18 (55.5%) of the neonates died. 13/18 (72%) of the neonates had late-onset neonatal sepsis, and 10/18 (55%) had low birth weight. Resistance to minocycline and chloramphenicol was 100%, 72.2% to meropenem; 72.2% NDM gene was found in neonates and was 20% from the environment. Conclusion: Outbreak of NDM-producing BCC resulting in high neonatal mortality in NICU.

Neonatal septicemia, or blood poisoning, is a dangerous illness in newborns. It is caused by bacteria or other infections entering the blood and spreading. Pregnancy, labor, delivery and exposure after birth can result in infection of the newborn. Neonatal septicemia kills 700,000 babies worldwide, mostly in low- and middle-income countries. Burkholderia cepacia complex bacteria can cause infections in people with weaker immune systems or other disorders. They are particularly dangerous in hospitals, as they can cause chronic lung problems. This study collected blood samples from newborns with blood poisoning. Most samples that contained Burkholderia cepacia complex were not susceptible to drugs. Four of the newborns carried the same bacteria, indicating that hospital staff should practice hand washing and equipment and environmental cleaning to prevent the spread of the bacteria.

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.

Transcriptional Response of Burkholderia cenocepacia H111 to Severe Zinc Starvation.

Burkholderia cenocepacia is an opportunistic pathogen that is primarily associated with severe respiratory infections in people with cystic fibrosis. These bacteria have significant intrinsic resistance to antimicrobial therapy, and there is a need for more effective treatments. Bacterial zinc uptake and homeostasis systems are attractive targets for new drugs, yet our understanding of how bacteria acquire and utilise zinc remains incomplete. Here we have used RNA-sequencing and differential gene expression analysis to investigate how B. cenocepacia H111 is able to survive in zinc poor environments, such as those expected to be encountered within the host. The data shows that 201 genes are significantly differentially expressed when zinc supply is severely limited. Included in the 85 upregulated genes, are genes encoding a putative ZnuABC high affinity zinc importer, two TonB-dependent outer membrane receptors that may facilitate zinc uptake across the outer cell membrane, and a COG0523 family zinc metallochaperone. Amongst the 116 downregulated genes, are several zinc-dependent enzymes suggesting a mechanism of zinc sparring to reduce the cells demand for zinc when bioavailability is low.

Identification of two distinct phylogenomic lineages and model strains for the understudied cystic fibrosis lung pathogen Burkholderia multivorans.

Burkholderia multivorans is the dominant Burkholderia pathogen recovered from lung infection in people with cystic fibrosis. However, as an understudied pathogen there are knowledge gaps in relation to its population biology, phenotypic traits and useful model strains. A phylogenomic study of B. multivorans was undertaken using a total of 283 genomes, of which 73 were sequenced and 49 phenotypically characterized as part of this study. Average nucleotide identity analysis (ANI) and phylogenetic alignment of core genes demonstrated that the B. multivorans population separated into two distinct evolutionary clades, defined as lineage 1 (n=58 genomes) and lineage 2 (n=221 genomes). To examine the population biology of B. multivorans, a representative subgroup of 77 B. multivorans genomes (28 from the reference databases and the 49 novel short-read genome sequences) were selected based on multilocus sequence typing (MLST), isolation source and phylogenetic placement criteria. Comparative genomics was used to identify B. multivorans lineage-specific genes - ghrB_1 in lineage 1 and glnM_2 in lineage 2 - and diagnostic PCRs targeting them were successfully developed. Phenotypic analysis of 49 representative B. multivorans strains showed considerable inter-strain variance, but the majority of the isolates tested were motile and capable of biofilm formation. A striking absence of B. multivorans protease activity in vitro was observed, but no lineage-specific phenotypic differences were demonstrated. Using phylogenomic and phenotypic criteria, three model B. multivorans CF strains were identified, BCC0084 (lineage 1), BCC1272 (lineage 2a) and BCC0033 lineage 2b, and their complete genome sequences determined. B. multivorans CF strains BCC0033 and BCC0084, and the environmental reference strain, ATCC 17616, were all capable of short-term survival within a murine lung infection model. By mapping the population biology, identifying lineage-specific PCRs and model strains, we provide much needed baseline resources for future studies of B. multivorans.

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.

Identification of Burkholderia cepacia Complex by PCR: A Simple Way.

United States Pharmacopeia (USP) General Chapter <60> for the detection of Burkholderia cepacia complex (Bcc) members in nonsterile products became official in December 2019. This isolation method requires confirmation of the identity of any growth found on Burkholderia cepacia Selective Agar (BCSA) by additional identification tests (refer to the Interpretation section). This article presents a singleplex polymerase chain reaction (PCR) method to rapidly confirm the membership of any microbial grown on BCSA (and other nutrient medium) in the Bcc group. This method is cost effective as it does not require expensive equipment or reagents; therefore, it can be easily adopted in the industry without an important investment. We validated this singleplex PCR Bcc identification method with previously published PCR primers with an expanded panel of 37 clinical and environmental Bcc isolates. The sources and repositories of these Bcc isolates include contaminated health products and medical devices, patients infected with cystic fibrosis, the National Microbiology Laboratory (NML) internal strain bank, and the American Type Culture Collection (ATCC). All 37 isolates that belong to the Bcc tested positive using our confirmatory identification method. Twenty-two negative controls including four isolates belonging to the genus Burkholderia tested negative as expected. Our work indicates that this singleplex PCR is an efficient confirmatory method for Bcc identification, and it can successfully supplement USP <60> for Bcc isolates identification found in pharmaceutical products.