Cepacia Syndrome in a Non-Cystic Fibrosis Patient

A Case Report of Necrotizing Pneumonia Due to Burkholderia cepacia Syndrome

Burkholderia cepacia ​​​​​​(B. cepacia) complex is a highly resistant gram-negative pathogen known to cause lung infection in cystic fibrosis, chronic granulomatous disease, and immunocompromised patients. However, it may rarely infect immunocompetent patients as well. Here, we present the case of a 30-year-old male patient who was treated for B. cepacia pneumonia in the hospital, discharged with oral antibiotics, and returned two months later with recurring B. cepacia pneumonia and bacteremia. The patient rapidly declined over the next 24 hours and expired in the intensive care unit. This case is significant as it is one of very few published cases of cepacia syndrome in a patient with no evidence of immunodeficiency. In conclusion, cases of B. cepacia pneumonia must be monitored vigilantly for progression to cepacia syndrome, even in immunocompetent patients. Additional studies regarding optimized antibiotic regimens and effective treatment modalities for B. cepacia infection are warranted.

Mechanism of Action and Resistance Evasion of an Antimicrobial Oligomer against Multidrug-Resistant Gram-Negative Bacteria

The last resort for treating multidrug-resistant (MDR) Pseudomonas aeruginosa and other MDR Gram-negative bacteria is a class of antibiotics called the polymyxins; however, polymyxin-resistant isolates have emerged. In response, antimicrobial peptides (AMPs) and their synthetic mimetics have been investigated as alternative therapeutic options. Oligothioetheramides (oligoTEAs) are a class of synthetic, sequence-defined oligomers composed of N-allylacrylamide monomers and an abiotic dithiol backbone that is resistant to serum degradation. Characteristic of other AMP mimetics, the precise balance between charge and hydrophobicity has afforded cationic oligoTEAs potent antimicrobial activity, particularly for the compound BDT-4G, which consists of a 1,4-butanedithiol backbone and guanidine pendant groups, the latter of which provides a cationic charge at physiological pH. However, the activity and mechanism of cationic oligoTEAs against MDR Gram-negative isolates have yet to be fully investigated. Herein, we demonstrated the potent antimicrobial activity of BDT-4G against clinical isolates of P. aeruginosa with a range of susceptibility profiles, assessed the kinetics of bactericidal activity, and further elucidated its mechanism of action. Activity was also evaluated against a panel of polymyxin-resistant isolates, including intrinsically-resistant species. We demonstrate that BDT-4G can evade some of the mechanisms conferring resistance to polymyxin B and thus may have therapeutic potential.

Iron metabolism in bacterial cells: from physiological significance to a new class of antimicrobial agents

Infectious complications in the respiratory tract caused by microorganisms from the Burkholderia cepacia complex are the main cause of death among patients with cystic fibrosis. Natural and acquired resistance mechanisms allow Burkholderia cepacia complex pathogens to adapt to the conditions of regular antibiotic therapy, which necessitates the use of antibacterial drugs with an alternative mechanism of action. Studies on the importance of iron as an essential factor in the metabolism of bacteria and methods of its acquisition from the environment contributed to the development of a new antibiotic from a number of cephalosporins – cefiderocol. In the structure of cefiderocol, a fragment is formed that imitates siderophores – chelating molecules that ensure the transport of iron ions into the internal environment of the microorganism. A unique mechanism, described in the scientific literature as a “Trojan horse”, allows antibiotic molecules conjugated with siderophores to effectively penetrate into the bacterial cell, exerting a bactericidal effect. Thus, cefiderocol can be used to treat infectious complications in the lungs of patients with cystic fibrosis caused by bacteria from the Burkholderia cepacia complex, including multidrug-resistant strains. In addition, the spectrum of activity of cefiderocol allows the use of this antibiotic in the treatment of infections caused by nosocomial gram-negative bacteria such as Enterobacterales, Acinetobacter, Pseudomonas and Stenotrophomonas.

Gasdermin D restricts Burkholderia cenocepacia infection in vitro and in vivo

Burkholderia cenocepacia (B. cenocepacia) is an opportunistic bacterium; causing severe life threatening systemic infections in immunocompromised individuals including cystic fibrosis patients. The lack of gasdermin D (GSDMD) protects mice against endotoxin lipopolysaccharide (LPS) shock. On the other hand, GSDMD promotes mice survival in response to certain bacterial infections. However, the role of GSDMD during B. cenocepacia infection is not yet determined. Our in vitro study shows that GSDMD restricts B. cenocepacia replication within macrophages independent of its role in cell death through promoting mitochondrial reactive oxygen species (mROS) production. mROS is known to stimulate autophagy, hence, the inhibition of mROS or the absence of GSDMD during B. cenocepacia infections reduces autophagy which plays a critical role in the restriction of the pathogen. GSDMD promotes inflammation in response to B. cenocepacia through mediating the release of inflammasome dependent cytokine (IL-1β) and an independent one (CXCL1) (KC). Additionally, different B. cenocepacia secretory systems (T3SS, T4SS, and T6SS) contribute to inflammasome activation together with bacterial survival within macrophages. In vivo study confirmed the in vitro findings and showed that GSDMD restricts B. cenocepacia infection and dissemination and stimulates autophagy in response to B. cenocepacia. Nevertheless, GSDMD promotes lung inflammation and necrosis in response to B. cenocepacia without altering mice survival. This study describes the double-edged functions of GSDMD in response to B. cenocepacia infection and shows the importance of GSDMD-mediated mROS in restriction of B. cenocepacia.

Management of Cepacia Syndrome With a Combination of Intravenous and Inhaled Antimicrobials in a Non-Cystic Fibrosis Pediatric Patient

Burkholderia cepacia complex (Bcc) is an opportunistic pathogen, posing little risk to healthy individuals. The presentation of Bcc can vary from a virtually asymptomatic chronic infection, to an acute, life-threatening necrotizing pneumonia, acute respiratory distress syndrome, and bacteremia (cepacia syndrome) associated with a mortality rate up to 75%. We present the successful treatment of a 17-year-old male with chronic granulomatous disorder who presented with cepacia syndrome and confirmed Bcc pneumonia using a novel antimicrobial approach. Despite initial IV antimicrobial therapy, our patient continued to decline, developing hypotension requiring pressor support and eventually extracorporeal membrane oxygenation. An aggressive, multimechanistic approach including the combination of nebulized tobramycin, IV sulfamethoxazole-trimethoprim, ceftazidime, enteral minocycline, and corticosteroids was implemented. This multimechanistic antimicrobial approach in combination with systemic corticosteroids led to the successful treatment of cepacia syndrome in the setting of necrotizing pneumonia due to B cepacia with full respiratory recovery. We suggest that in patients with cepacia syndrome who continue to decline despite IV antimicrobial therapy, using multiple antimicrobial mechanisms of action may improve clinical outcomes.

Staphylococcus aureus products subvert the Burkholderia cenocepacia-induced inflammatory response in airway epithelial cells

Introduction. Chronic pulmonary infection is associated with colonization with multiple micro-organisms but host-microbe and microbe-microbe interactions are poorly understood.Aim. This study aims to investigate the differences in host responses to mono- and co-infection with S. aureus and B. cenocepacia in human airway epithelial cells.Methodology. We assessed the effect of co-infection with B. cenocepacia and S. aureus on host signalling and inflammatory responses in the human airway epithelial cell line 16HBE, using ELISA and western blot analysis.Results. The results show that B. cenocepacia activates MAPK and NF-κB signalling pathways, subsequently eliciting robust interleukin (IL)-8 production. However, when airway epithelial cells were co-treated with live B. cenocepacia bacteria and S. aureus supernatants (conditioned medium), the pro-inflammatory response was attenuated. This anti-inflammatory effect was widely exhibited in the S. aureus isolates tested and was mediated via reduced MAPK and NF-κB signalling, but not via IL-1 receptor or tumour necrosis factor receptor modulation. The staphylococcal effectors were characterized as small, heat-stable, non-proteinaceous and not cell wall-related factors.Conclusion. This study demonstrates for the first time the host response in a S. aureus/B. cenocepacia co-infection model and provides insight into a staphylococcal immune evasion mechanism, as well as a therapeutic intervention for excessive inflammation.

Refractory Burkholderia cepacia bacteraemia from a consolidation pneumonia lasting more than 7 weeks, successfully treated with systemic antibiotics and nebulised meropenem

We present a case of a 55-year-old Filipino man who was transferred from another institution where he was recently diagnosed with Crohn's disease but not started on any immunosuppressants. He underwent laparoscopic cholecystectomy with T-tube placement a few weeks prior to admission. On workup, abdominal CT scan was unremarkable, but blood cultures on the third hospital day grew Burkholderia cepacia Antibiotic regimen was shifted to ceftazidime and levofloxacin. The bacteraemia and febrile episodes persisted despite removal of the central line and T tube. White blood cell scan and chest CT scan showed left-sided consolidation pneumonia. Blood cultures continued to grow B. cepacia despite shifting to meropenem and trimethoprim-sulfamethoxazole. Meropenem nebulisation at 250 mg every 12 hours was added to the regimen on the third week then oral minocycline was added on the fourth week due to persistence of bacteraemia. He subsequently developed a small vegetation on the aortic valve, so amikacin was added. Fever lysed on the sixth week, but the B. cepacia bacteraemia persisted, clearing only on the 51st hospital day. The patient was discharged with a plan to continue antibiotics, including meropenem nebulisation, for 6 more weeks. On follow-up, the patient had no recurrence of fever. There was also resolution of consolidation on chest CT scan and disappearance of vegetation on echocardiography.

Burkholderia Cepacia Complex Causing Pneumonia in an Immunocompetent Non-Cystic Fibrosis Patient: Case Report and Review of Literature

BACKGROUND

Burkholderia cepacia complex is widespread in the environment and has been recognized as a cause of opportunistic pulmonary infections, particularly in patients with Cystic Fibrosis (CF). The natural ecology of the bacteria as part of plant growth-promoting rhizosphere provides stark contrast to its infectious potential. Its preponderance as a nosocomial pathogen may be due to its ability to survive in antiseptic solutions, contaminate equipments and intrinsic antimicrobial resistance.

CASE

An elderly, diabetic male was evaluated for hemoptysis, fever and cough. Chest computed tomography showed a thick walled cavity in the left lung and hilar lymphadenopathy. Sputum examination showed Gram negative bacilli and no acid fast bacilli. Sputum culture yielded growth of non-fermentative Gram negative bacilli on two occasions, but blood culture was sterile. The isolate was identified as B. cepacia by Matrix Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS). The patient's general condition remained poor and in spite of initiation of antibiotics, the patient expired after an episode of massive hemoptysis.

CONCLUSION

This report raises concerns regarding the spread and severity of B. cepacia infection in non-compromised patients in the community and the need to suspect and identify it. Since the organism is inherently resistant to antipseudomonal penicillins, aminoglycosides and polymyxin B, differentiation from Pseudomonas spp. and determining antimicrobial susceptibility is paramount for treatment.

Burkholderia contaminans Colonization from Contaminated Liquid Docusate (Colace) in a Immunocompetent Adult with Legionnaire's Disease: Infection Control Implications and the Potential Role of Candida pellucosa

Objective:B. contaminans was cultured from respiratory secretions and liquid docusate (Colace) in a Neurosurgical Intensive Care Unit (NICU) patient with community-acquired Legionnaire’s disease but not from another bottle given to the patient. Unexpectedly, C. pelliculosa was cultured from two bottles, but not the B. contaminans bottle or respiratory secretions. Methods:B. cepacia, later identified as B. contaminans, was cultured from a bottle of liquid docusate (Colace) dispensed to a non-cystic fibrosis patient. His respiratory secretions were colonized with B. contaminans. Results: Eradication of B. contaminans colonization in the patient’s respiratory secretions was attempted. With levofloxacin, B. contaminans developed multidrug resistance (MDR). Subsequent TMP-SMX therapy did not result in further MDR. Nine other ICU patients were given docusate from the same lot, but there were no other B. contaminans isolates. Conclusion:B. contaminans colonization of respiratory secretion may be difficult to eliminate. The significance of C. pelliculosa cultured from liquid docusate (Colace) remains to be elucidated. In this case, it appeared that B. contaminans may have inhibited the growth of C. pelliculosa in the same bottle. Others should be alerted to the possibility that C. pelliculosa may be present in B. contaminans–contaminated lots of liquid docusate (Colace).