Burkholderia cepacia complex: beyond pseudomonas and acinetobacter

Burkholderia cepacia Complex Producing a Peculiar Violet Pigment: A Case Series From a Tertiary Care Hospital in Meghalaya

The Burkholderia cepacia complex (BCC) represents a group of bacteria that are gram-negative, aerobic, and non-fermenters. They are notorious for causing infections in vulnerable individuals, such as those with compromised immune systems. Examples are patients suffering from cystic fibrosis or chronic granulomatous disease. These bacteria are prevalent in diverse habitats, like soil and water. Over the last four decades, they have gained recognition as both emerging opportunistic pathogens and nosocomial threats. Managing BCC infections poses significant challenges due to their inherent resistance to numerous antibiotics, thus raising substantial concerns within clinical settings. Here, we present a case series of bacteremia, with BCC as the causative organism. The isolates showed a curious phenomenon of producing a violet pigment.

Four novel Acinetobacter lwoffii strains isolated from the milk of cows in China with subclinical mastitis

BACKGROUND

Acinetobacter lwoffii (A. lwoffii) is a Gram-negative bacteria common in the environment, and it is the normal flora in human respiratory and digestive tracts. The bacteria is a zoonotic and opportunistic pathogen that causes various infections, including nosocomial infections. The aim of this study was to identify A. lwoffii strains isolated from bovine milk with subclinical mastitis in China and get a better understanding of its antimicrobial susceptibility and resistance profile. This is the first study to analyze the drug resistance spectrum and corresponding mechanisms of A. lwoffii isolated in raw milk.

RESULTS

Four A. lwoffii strains were isolated by PCR method. Genetic evolution analysis using the neighbor-joining method showed that the four strains had a high homology with Acinetobacter lwoffii. The strains were resistant to several antibiotics and carried 17 drug-resistance genes across them. Specifically, among 23 antibiotics, the strains were completely susceptible to 6 antibiotics, including doxycycline, erythromycin, polymyxin, clindamycin, imipenem, and meropenem. In addition, the strains showed variable resistance patterns. A total of 17 resistance genes, including plasmid-mediated resistance genes, were detected across the four strains. These genes mediated resistance to 5 classes of antimicrobials, including beta-lactam, aminoglycosides, fluoroquinolones, tetracycline, sulfonamides, and chloramphenicol.

CONCLUSION

These findings indicated that multi-drug resistant Acinetobacter lwoffii strains exist in raw milk of bovine with subclinical mastitis. Acinetobacter lwoffii are widespread in natural environmental samples, including water, soil, bathtub, soap box, skin, pharynx, conjunctiva, saliva, gastrointestinal tract, and vaginal secretions. The strains carry resistance genes in mobile genetic elements to enhance the spread of these genes. Therefore, more attention should be paid to epidemiological surveillance and drug resistant A. lwoffii.

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.

Specific biomarker mining and rapid detection of Burkholderia cepacia complex by recombinase polymerase amplification

Objective

To mine specific proteins and their protein-coding genes as suitable molecular biomarkers for the Burkholderia cepacia Complex (BCC) bacteria detection based on mega analysis of microbial proteomic and genomic data comparisons and to develop a real-time recombinase polymerase amplification (rt-RPA) assay for rapid isothermal screening for pharmaceutical and personal care products.

Methods

We constructed an automatic screening framework based on Python to compare the microbial proteomes of 78 BCC strains and 263 non-BCC strains to identify BCC-specific protein sequences. In addition, the specific protein-coding gene and its core DNA sequence were validated in silico with a self-built genome database containing 158 thousand bacteria. The appropriate methodology for BCC detection using rt-RPA was evaluated by 58 strains in pure culture and 33 batches of artificially contaminated pharmaceutical and personal care products.

Results

We identified the protein SecY and its protein-coding gene secY through the automatic comparison framework. The virtual evaluation of the conserved region of the secY gene showed more than 99.8% specificity from the genome database, and it can distinguish all known BCC species from other bacteria by phylogenetic analysis. Furthermore, the detection limit of the rt-RPA assay targeting the secY gene was 5.6 × 102 CFU of BCC bacteria in pure culture or 1.2 pg of BCC bacteria genomic DNA within 30 min. It was validated to detect <1 CFU/portion of BCC bacteria from artificially contaminated samples after a pre-enrichment process. The relative trueness and sensitivity of the rt-RPA assay were 100% in practice compared to the reference methods.

Conclusion

The automatic comparison framework for molecular biomarker mining is straightforward, universal, applicable, and efficient. Based on recognizing the BCC-specific protein SecY and its gene, we successfully established the rt-RPA assay for rapid detection in pharmaceutical and personal care products.

Role of Matrix-Assisted Laser Desorption Ionization-Time-of-Flight Mass Spectrometry for Species Identification of Acinetobacter Strains

Introduction   Acinetobacter species has become a leading cause of nosocomial infections in recent years. Objectives  The aim of the study was to establish the usefulness of matrix-assisted laser desorption ionization-time-of-flight (MALDI-TOF) mass spectrometry (MS) for the identification of Acinetobacter species with respect to conventional biochemical methods and MicroScan WalkAway 96 Plus system and to compare the antibiotic susceptibility test results Kirby-Bauer disk diffusion method with MicroScan WalkAway 96 Plus automated identification and antimicrobial susceptibility testing system. Materials and Methods  The study sample comprised 100 clinical isolates of Acinetobacter species. They were all identified using MALDI-TOF MS and compared with other two identification systems. Statistical Analysis  Comparison of categorical variables by Fisher's exact test or Pearson's chi-square test was done. All statistical tools were two tailed, and a significant level p  < 0.05 was used. All statistical tests were performed using SPSS v22.0 (Armonk IBM Corp., New York, United States). Cohen's kappa coefficients were also calculated and used as applicable. Results  MALDI-TOF MS revealed 92 A. baumannii , 2 Acinetobacter nosocomialis , 3 Acinetobacter lwoffii , and 1 each was identified as Acinetobacter junii , Acinetobacter johnsonii , and Acinetobacter tandoii . There was moderate agreement between identification by MicroScan WalkAway and MALDI-TOF, and substantial agreement between conventional biochemical tests and MALDI-TOF. We found that there was a 100% categorical agreement with respect to susceptibility of aminoglycosides (amikacin, gentamicin, tobramycin) and cephalosporins (ceftazidime, cefepime, cefotaxime) between disk diffusion method and MicroScan WalkAway 96 Plus system. Total of 16 errors were observed. Conclusion  Although MALDI-TOF MS could be useful to identify A. baumannii but not other species in the genus, it is a rapid, reliable method and can be routinely used in clinical laboratories.

Burkholderia cepacia infection associated with sickle cell disease: An uncommon entity

Burkholderia, a multidrug-resistant Gram-negative bacteria, is an uncommon cause of infection mostly in immunocompromised patients with a clinical profile very similar to tuberculosis. The most common conditions associated with this organism are cystic fibrosis and chronic granulomatous diseases. Bacteremia with it occurs in patients who are chronically ill and associated with significant morbidity and mortality. We are reporting here a case of perisplenic intra-abdominal abscess caused by Burkholderia cepacia in a patient with sickle cell disease (SCD).

Genomic features, antimicrobial susceptibility, and epidemiological insights into Burkholderia cenocepacia clonal complex 31 isolates from bloodstream infections in India

Introduction

Burkholderia cepacia complex (Bcc) clonal complex (CC) 31, the predominant lineage causing devastating outbreaks globally, has been a growing concern of infections in non-cystic fibrosis (NCF) patients in India. B. cenocepacia is very challenging to treat owing to its virulence determinants and antibiotic resistance. Improving the management of these infections requires a better knowledge of their resistance patterns and mechanisms.

Methods

Whole-genome sequences of 35 CC31 isolates obtained from patient samples, were analyzed against available 210 CC31 genomes in the NCBI database to glean details of resistance, virulence, mobile elements, and phylogenetic markers to study genomic diversity and evolution of CC31 lineage in India.

Results

Genomic analysis revealed that 35 isolates belonging to CC31 were categorized into 11 sequence types (ST), of which five STs were reported exclusively from India. Phylogenetic analysis classified 245 CC31 isolates into eight distinct clades (I-VIII) and unveiled that NCF isolates are evolving independently from the global cystic fibrosis (CF) isolates forming a distinct clade. The detection rate of seven classes of antibiotic-related genes in 35 isolates was 35 (100%) for tetracyclines, aminoglycosides, and fluoroquinolones; 26 (74.2%) for sulphonamides and phenicols; 7 (20%) for beta-lactamases; and 1 (2.8%) for trimethoprim resistance genes. Additionally, 3 (8.5%) NCF isolates were resistant to disinfecting agents and antiseptics. Antimicrobial susceptibility testing revealed that majority of NCF isolates were resistant to chloramphenicol (77%) and levofloxacin (34%). NCF isolates have a comparable number of virulence genes to CF isolates. A well-studied pathogenicity island of B. cenocepacia, GI11 is present in ST628 and ST709 isolates from the Indian Bcc population. In contrast, genomic island GI15 (highly similar to the island found in B. pseudomallei strain EY1) is exclusively reported in ST839 and ST824 isolates from two different locations in India. Horizontal acquisition of lytic phage ST79 of pathogenic B. pseudomallei is demonstrated in ST628 isolates Bcc1463, Bcc29163, and BccR4654 amongst CC31 lineage.

Discussion

The study reveals a high diversity of CC31 lineages among B. cenocepacia isolates from India. The extensive information from this study will facilitate the development of rapid diagnostic and novel therapeutic approaches to manage B. cenocepacia infections.

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

BACKGROUND

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.

METHODS

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.

RESULTS

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).

CONCLUSIONS

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.

The Class A β-Lactamase Produced by Burkholderia Species Compromises the Potency of Tebipenem against a Panel of Isolates from the United States

Tebipenem-pivoxil hydrobromide, an orally bioavailable carbapenem, is currently in clinical development for the treatment of extended-spectrum β-lactamase- and AmpC-producing Enterobacterales. Previously, tebipenem was found to possess antimicrobial activity against the biothreat pathogens, Burkholderia pseudomallei and Burkholderia mallei. Thus, herein, tebipenem was evaluated against a panel of 150 curated strains of Burkholderia cepacia complex (Bcc) and Burkholderia gladioli, pathogens that infect people who are immunocompromised or have cystic fibrosis. Using the provisional susceptibility breakpoint of 0.12 mg/L for tebipenem, 100% of the Bcc and B. gladioli tested as being provisionally resistant to tebipenem. Bcc and B. gladioli possess two inducible chromosomal β-lactamases, PenA and AmpC. Using purified PenA1 and AmpC1, model β-lactamases expressed in Burkholderia multivorans ATCC 17616, PenA1 was found to slowly hydrolyze tebipenem, while AmpC1 was inhibited by tebipenem with a k₂/K value of 1.9 ± 0.1 × 10³ M⁻¹s⁻¹. In addition, tebipenem was found to be a weak inducer of bla_PenA1 expression. The combination of the slow hydrolysis by PenA1 and weak induction of bla_PenA1 likely compromises the potency of tebipenem against Bcc and B. gladioli.

Burkholderia cepacia Complex Lumbar Spondylodiscitis: A Rare Nosocomial Infection

Pyogenic spondylodiscitis is rarely caused by Burkholderia cepacia complex. B. cepacia is widespread in the environment and recognized as an opportunistic pathogen for patients with cystic fibrosis and immune disorders. A female in her mid-30s with underlying hyperthyroidism, but otherwise immunocompetent, was admitted to the hospital with persistent lower back pain after elective bariatric surgery in Mexico. Lumbar MRI showed L2/L3 osteomyelitis and discitis. Culture of disk aspiration grew Burkholderia cepacia complex sensitive to cefepime, ceftazidime, ciprofloxacin, gentamicin, imipenem, levofloxacin, and trimethoprim-sulfamethoxazole. The infection failed to respond to cefepime; however, she was successfully treated with levofloxacin monotherapy.

Exposure and Health Effects of Bacteria in Healthcare Units: An Overview

Healthcare units consist of numerous people circulating daily, such as workers, patients, and companions, and these people are vehicles for the transmission of microorganisms, such as bacteria. Bacteria species may have different allergenic, pathogenic, infectious, or toxic properties that can affect humans. Hospital settings foment the proliferation of bacteria due to characteristics present in the indoor hospital environment. This review article aims to identify the potential health effects caused by bacterial contamination in the context of healthcare units, both in patients and in workers. A search was carried out for articles published in PubMed, Web of Science and Scopus, between 1 January 2000 and 31 October 2021, using the descriptor hospital exposure assessment bacteria. This bibliographic research found a total of 13 articles. Bacteria transmission occurs mainly due to the contact between healthcare workers and patients or through the handling of/contact with contaminated instruments or surfaces. The most common bacterial contaminants are Escherichia coli, Pseudomonas aeruginosa, Staphylococcus spp., Staphylococcus aureus and Micrococcus luteus, and the principal health effects of these contaminants are hospital-acquired infections and infections in immunocompromised people. A tight control of the disinfection methods is thus required, and its frequency must be increased to remove the microbial contamination of wards, surfaces and equipment. A better understanding of seasonal variations is important to prevent peaks of contamination.

Meropenem-Resistant Pandoraea Pneumonia in a Critically Ill Patient With COVID-19

Among patients infected with respiratory viruses, primary coinfection or secondary bacterial pneumonia is common in the severely ill. Pandoraea are multi-drug resistant gram-negative bacilli that have been newly classified in the past 20 years. We present the first reported case of Pandoraea co-infection with SARS-CoV-2 infection. A critically ill gentleman with COVID-19 in acute respiratory distress syndrome (ARDS) requiring mechanical ventilation developed ventilator-associated bacterial pneumonia (VAP). Initial sputum cultures grew Pandoraea species, with subsequent cultures growing P. aeruginosa, and K. pneumoniae as well. The patient failed to improve despite several antibiotic regimens including meropenem. Send-out reference laboratory testing of the Pandoraea species showed susceptibility to amikacin, ciprofloxacin, levofloxacin, imipenem, and minocycline, but resistance to aztreonam, cefepime, ceftazidime, and meropenem. The patient had deteriorated to multi-organ failure by the time minocycline was initiated, and his family had transitioned him into hospice care. Carbapenems are vital agents in the treatment of VAP. Pandoraea species are often resistant to meropenem but often retain in-vitro sensitivity to imipenem-cilastin. Although mainly isolated from respiratory specimens of patients with cystic fibrosis, cases of infection in non-cystic fibrosis patients have been increasingly recognized. The presentation of this case aims to increase awareness of the high drug resistance of this rising species and reduce delays in treatment, especially in COVID-19 coinfection.

Activity of imipenem-relebactam against multi-drug and extensively-drug resistant Burkholderia cepacia complex and Burkholderia gladioli

The Burkholderia cepacia complex (Bcc) and Burkholderia gladioli are opportunistic pathogens that most commonly infect persons with cystic fibrosis or compromised immune systems. Members of the Burkholderia genus are intrinsically multidrug resistant (MDR), possessing both a PenA carbapenemase and an AmpC β-lactamase, which renders treatment of infection due to these species problematic. Here, we tested the β-lactam-β-lactamase inhibitor combination, imipenem-relebactam, against a panel of MDR Bcc and B. gladioli. The addition of relebactam to imipenem dramatically lowered the MICs for Bcc and B. gladioli with only 16% of isolates testing susceptible to imipenem vs. 71.3% being susceptible to the imipenem-relebactam combination. While ceftazidime-avibactam remained the most potent combination drug against this panel of Bcc and B. gladioli, imipenem-relebactam was active against 71.4% of the ceftazidime-avibactam-resistant isolates. Relebactam demonstrated potent inactivation of the Burkholderia multivorans PenA1 with a K_{i app} value of 3.2 μM. Timed mass spectrometry revealed that PenA1 formed a very stable adduct with relebactam, without any detectable desulfation up to 24 hours. Based on our results, imipenem-relebactam may represent an alternative salvage therapy for Bcc and B. gladioli infection, especially in cases where the isolates are resistant to ceftazidime-avibactam.

Antimicrobial susceptibility pattern of Burkholderia cepacia complex & Stenotrophomonas maltophilia from North India: Trend over a decade (2007-2016)

Background & objectives

With increased isolation of Burkholderia cepacia complex (Bcc) and Stenotrophomonas maltophilia from clinical specimens, knowledge of their antimicrobial susceptibility trend will aid in better patient management. This study provides a comprehensive picture of this trend over a decade.

Methods

A retrospective analysis of laboratory records over 10 years for antimicrobial susceptibility pattern of Bcc and S. maltophilia was carried out. The susceptibility pattern to commonly used antimicrobials was determined using disk diffusion and compared at the beginning, mid and end of the study period.

Results

Five hundred and thirty Bcc and 665 S. maltophilia isolated over the past 10 yr were included in the study. Over the years, susceptibility of Bcc for co-trimoxazole varied as 80, 70 and 89 per cent at the beginning, middle and end of the study, respectively. Susceptibility to tetracycline was 43 per cent at the beginning of the study and that to minocycline was 100 per cent mid-study and 74 per cent at the end. Susceptibility to ceftazidime varied as 83, 60 and 65 per cent, respectively, and to meropenem, increased during the first half of the study and decreased in the second half, as 60, 70 and 43 per cent, respectively. Bcc susceptibility to levofloxacin decreased from 84 (in 2014) to 76 per cent (in 2016). S. maltophilia susceptibility to co-trimoxazole varied as 90, 82 and 87 per cent, respectively, whereas that to levofloxacin was 80, 100 and 94 per cent, respectively, during the start, mid and end of the study. Susceptibility to minocycline decreased from 100 per cent mid-study to 96 per cent at the end. Susceptibility of S. maltophilia to ceftazidime increased from 24 (in 2012) to 37 per cent (in 2016). All variations among the three phases of the study were significant for all antimicrobials tested for both the organisms.

Interpretation & conclusions

While Bcc showed increased resistance to ceftazidime, meropenem and minocycline, S. maltophilia maintained >80 per cent susceptibility to minocycline, levofloxacin and co-trimoxazole throughout the decade. By 2016, Bcc was most susceptible to co-trimoxazole, whereas S. maltophilia was most susceptible to minocycline and levofloxacin.

Intracellular survival and innate immune evasion of Burkholderia cepacia: Improved understanding of quorum sensing-controlled virulence factors, biofilm, and inhibitors

Burkholderia cepacia complex (Bcc) are opportunistic pathogens implicated with nosocomial infections, and high rates of morbidity and mortality, especially in individuals with cystic fibrosis (CF). B. cepacia are naturally resistant to different classes of antibiotics, and can subvert the host innate immune responses by producing quorum sensing (QS) controlled virulence factors and biofilms. It still remains a conundrum as to how exactly the bacterium survives the intracellular environment within the host cells of CF patients and immunocompromised individuals although the bacterium can invade human lung epithelial cells, neutrophils, and murine macrophages. The mechanisms associated with intracellular survival in the airway epithelial cells and the role of QS and virulence factors in B. cepacia infections in cystic fibrosis remain largely unclear. The current review focuses on understanding the role of QS-controlled virulence factors and biofilms, and provides additional impetus to understanding the potentials of QS-inhibitory strategies against B. cepacia.

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.

"Switching Partners": Piperacillin-Avibactam Is a Highly Potent Combination against Multidrug-Resistant Burkholderia cepacia Complex and Burkholderia gladioli Cystic Fibrosis Isolates

In persons with cystic fibrosis (CF), airway infection with Burkholderia cepacia complex (Bcc) species or Burkholderia gladioli presents a significant challenge due to inherent resistance to multiple antibiotics. Two chromosomally encoded inducible β-lactamases, a Pen-like class A and AmpC are produced in Bcc and B. gladioli Previously, ceftazidime-avibactam demonstrated significant potency against Bcc and B. gladioli isolated from the sputum of individuals with CF; however, 10% of the isolates tested resistant to ceftazidime-avibactam. Here, we describe an alternative antibiotic combination to overcome ceftazidime-avibactam resistance. Antimicrobial susceptibility testing was performed on Bcc and B. gladioli clinical and control isolates. Biochemical analysis was conducted on purified PenA1 and AmpC1 β-lactamases from Burkholderia multivorans ATCC 17616. Analytic isoelectric focusing and immunoblotting were conducted on cellular extracts of B. multivorans induced by various β-lactams or β-lactam-β-lactamase inhibitor combinations. Combinations of piperacillin-avibactam, as well as piperacillin-tazobactam plus ceftazidime-avibactam (the clinically available counterpart), were tested against a panel of ceftazidime-avibactam nonsusceptible Bcc and B. gladioli The piperacillin-avibactam and piperacillin-tazobactam-ceftazidime-avibactam combinations restored susceptibility to 99% of the isolates tested. Avibactam is a potent inhibitor of PenA1 (apparent inhibitory constant [K_{i app}] = 0.5 μM), while piperacillin was found to inhibit AmpC1 (K_{i app} = 2.6 μM). Moreover, piperacillin, tazobactam, ceftazidime, and avibactam, as well as combinations thereof, did not induce expression of bla _penA1 and bla _ampC1 in the B. multivorans ATCC 17616 background. When ceftazidime-avibactam is combined with piperacillin-tazobactam, the susceptibility of Bcc and B. gladioli to ceftazidime and piperacillin is restored in vitro Both the lack of bla _penA1 induction and potent inactivation of PenA1 by avibactam likely provide the major contributions toward susceptibility. With in vivo validation, piperacillin-tazobactam-ceftazidime-avibactam may represent salvage therapy for individuals with CF and highly drug-resistant Bcc and B. gladioli infections.

Ultrasound gel as a source of hospital outbreaks: Indian experience and literature review

Purpose

Hospital outbreaks are observed increasingly worldwide with various organisms from different sources such as contaminated ultrasound gel, intravenous (IV) fluids and IV medications. Among these, ultrasound gel is one of the most commonly reported sources for Burkholderia cepacia complex (Bcc) outbreaks. In this study, we describe our experience on investigation and the management of Bcc bacteraemia outbreak due to contaminated ultrasound gel from a tertiary care centre, South India.

Materials and Methods

Over a 10-day period in October 2016, seven children in our Paediatric intensive care unit (ICU) were found to have bacteraemia with Bcc isolated from their blood culture. Repeated isolation of the same organism with similar antimicrobial susceptibility pattern over a short incubation period from the same location, confirmed the outbreak. An active outbreak investigation, including environmental surveillance, was carried out to find the source and control the outbreak. Isolates were subjected to multi-locus sequence typing (MLST) and global eBURST (goeBURST) analysis.

Results

Environmental surveillance revealed contaminated ultrasound gel as the source of infection. MLST and goeBURST analysis confirmed that the outbreak was caused by a novel sequence type 1362 with the same clonal complex CC517. The outbreak was controlled by stringent infection control measures, withdrawal of contaminated ultrasound gel from regular usage and implementing the practice of using ultrasonogram (USG) probe cover for USG screening and guided procedures.

Conclusion

This report highlights the importance of early identification of an outbreak, prompt response of the ICU and infection control teams, sound environmental and epidemiological surveillance methods to identify the source and stringent infection control measures to control the outbreak. Contaminated ultrasound gel can be a potential source for healthcare-associated infection, which cannot be overlooked.

Resurrecting Old β-Lactams: Potent Inhibitory Activity of Temocillin against Multidrug-Resistant Burkholderia Species Isolates from the United States

Burkholderia spp. are opportunistic human pathogens that infect persons with cystic fibrosis and the immunocompromised. Burkholderia spp. express class A and C β-lactamases, which are transcriptionally regulated by PenR_A through linkage to cell wall metabolism and β-lactam exposure. The potency of temocillin, a 6-methoxy-β-lactam, was tested against a panel of multidrug-resistant (MDR) Burkholderia spp. In addition, the mechanistic basis of temocillin activity was assessed and compared to that of ticarcillin. Susceptibility testing with temocillin and ticarcillin was conducted, as was biochemical analysis of the PenA1 class A β-lactamase and AmpC1 class C β-lactamase. Molecular dynamics simulations (MDS) were performed using PenA1 with temocillin and ticarcillin. The majority (86.7%) of 150 MDR Burkholderia strains were susceptible to temocillin, while only 4% of the strains were susceptible to ticarcillin. Neither temocillin nor ticarcillin induced bla expression. Ticarcillin was hydrolyzed by PenA1 (k _cat/K_m = 1.7 ± 0.2 μM^-1 s^-1), while temocillin was slow to form a favorable complex (apparent K_i [K_{i  app}] = ∼2 mM). Ticarcillin and temocillin were both potent inhibitors of AmpC1, with K_{i  app} values of 4.9 ± 1.0 μM and 4.3 ± 0.4 μM, respectively. MDS of PenA revealed that ticarcillin is in an advantageous position for acylation and deacylation. Conversely, with temocillin, active-site residues K73 and S130 are rotated and the catalytic water molecule is displaced, thereby slowing acylation and allowing the 6-methoxy of temocillin to block deacylation. Temocillin is a β-lactam with potent activity against Burkholderia spp., as it does not induce bla expression and is poorly hydrolyzed by endogenous β-lactamases.

Burkholderia cepacia: An Outbreak in the Peritoneal Dialysis Unit

Burkholderia cepacia is a ubiquitous, opportunistic, environmental gram-negative bacillus which most commonly affects cystic fibrosis and immunocompromised patients. Rarely, it can cause peritoneal dialysis (PD) exit-site infection (ESI). Information relating to predisposing factors, clinical course, and treatment options for B. cepacia ESIs is limited. Although reports of B. cepacia healthcare-associated infections exist, outbreaks in PD units have not previously been reported. A recent outbreak of B. cepacia ESI in our PD unit provided a unique opportunity to study B. cepacia ESIs and to outline an approach to investigating such an outbreak.

After unexpectedly identifying B. cepacia as the cause of PD catheter ESIs in 3 patients over an 11-week period, we began systematically screening our PD population for B. cepacia exit-site colonization. A further 6 patients were found to be affected, 3 with asymptomatic colonization and 3 with symptomatic B. cepacia ESI. Four of the 6 developed tunnel infections requiring multiple courses of antibiotic treatment, and 3 patients required catheter removal; 2 patients with symptomatic ESIs without tunnel involvement responded to oral and topical antibiotics. Further investigation implicated 4% chlorhexidine aqueous bodywash used by all patients as the probable source of the outbreak.

This is the first reported outbreak of B. cepacia ESIs. We noted an association between diabetes mellitus and refractory/more extensive infection. Our experience suggests that isolated ESIs can be treated successfully with oral antibiotics whereas tunnel infections generally require catheter removal.

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.

Epidemiological investigation and successful management of a Burkholderia cepacia outbreak in a neurotrauma intensive care unit

OBJECTIVE

The detailed epidemiological and molecular characterization of an outbreak of Burkholderia cepacia at a neurotrauma intensive care unit of a level 1 trauma centre is described. The stringent infection control interventions taken to successfully curb this outbreak are emphasized.

METHODS

The clinical and microbiological data for those patients who had more than one blood culture that grew B. cepacia were reviewed. Bacterial identification and antimicrobial susceptibility testing was done using automated Vitek 2 systems. Prospective surveillance, environmental sampling, and multilocus sequence typing (MLST) were performed for extensive source tracking. Intensive infection control measures were taken to further control the hospital spread.

RESULTS

Out of a total 48 patients with B. cepacia bacteraemia, 15 (31%) had central line-associated blood stream infections. Two hundred and thirty-one environmental samples were collected and screened, and only two water samples grew B. cepacia with similar phenotypic characteristics. The clinical strains characterized by MLST typing were clonal. However, isolates from the water represented a novel strain type (ST-1289). Intensive terminal cleaning, disinfection of the water supply, and the augmentation of infection control activities were done to curb the outbreak. A subsequent reduction in bacteraemia cases was observed.

CONCLUSION

Early diagnosis and appropriate therapy, along with the rigorous implementation of essential hospital infection control practices is required for successful containment of this pathogen and to curb such an outbreak.

Characterization of the AmpC β-Lactamase from Burkholderia multivorans

Burkholderia multivorans is a member of the Burkholderia cepacia complex, a group of >20 related species of nosocomial pathogens that commonly infect individuals suffering from cystic fibrosis. β-Lactam antibiotics are recommended as therapy for infections due to Bmultivorans, which possesses two β-lactamase genes, bla_penA and bla_AmpC PenA is a carbapenemase with a substrate profile similar to that of the Klebsiella pneumoniae carbapenemase (KPC); in addition, expression of PenA is inducible by β-lactams in Bmultivorans Here, we characterize AmpC from Bmultivorans ATCC 17616. AmpC possesses only 38 to 46% protein identity with non-Burkholderia AmpC proteins (e.g., PDC-1 and CMY-2). Among 49 clinical isolates of Bmultivorans, we identified 27 different AmpC variants. Some variants possessed single amino acid substitutions within critical active-site motifs (Ω loop and R2 loop). Purified AmpC1 demonstrated minimal measurable catalytic activity toward β-lactams (i.e., nitrocefin and cephalothin). Moreover, avibactam was a poor inhibitor of AmpC1 (K_iapp > 600 μM), and acyl-enzyme complex formation with AmpC1 was slow, likely due to lack of productive interactions with active-site residues. Interestingly, immunoblotting using a polyclonal anti-AmpC antibody revealed that protein expression of AmpC1 was inducible in Bmultivorans ATCC 17616 after growth in subinhibitory concentrations of imipenem (1 μg/ml). AmpC is a unique inducible class C cephalosporinase that may play an ancillary role in Bmultivorans compared to PenA, which is the dominant β-lactamase in Bmultivorans ATCC 17616.

Sequence heterogeneity of the PenA carbapenemase in clinical isolates of Burkholderia multivorans

Multidrug-resistant gram-negative pathogens are a significant health threat. Burkholderia spp. encompass a complex subset of gram-negative bacteria with a wide range of biological functions that include human, animal, and plant pathogens. The treatment of infections caused by Burkholderia spp. is problematic due to their inherent resistance to multiple antibiotics. The major β-lactam resistance determinant expressed in Burkholderia spp. is a class A β-lactamase of the PenA family. In this study, significant amino acid sequence heterogeneity was discovered in PenA (37 novel variants) within a panel of 48 different strains of Burkholderia multivorans isolated from individuals with cystic fibrosis. Phylogenetic analysis distributed the 37 variants into 5 groups based on their primary amino acid sequences. Amino acid substitutions were present throughout the entire β-lactamase and did not congregate to specific regions of the protein. The PenA variants possessed 5 to 17 single amino acid changes. The N189S and S286I substitutions were most prevalent and found in all variants. Due to the sequence heterogeneity in PenA, a highly conserved peptide (18 amino acids) within PenA was chosen as the antigen for polyclonal antibody production in order to measure expression of PenA within the 48 clinical isolates of B. multivorans. Characterization of the anti-PenA peptide antibody, using immunoblotting approaches, exposed several unique features of this antibody (i.e., detected <500 pg of purified PenA, all 37 PenA variants in B. multivorans, and Pen-like β-lactamases from other species within the Burkholderia cepacia complex). The significant sequence heterogeneity found in PenA may have occurred due to selective pressure (e.g., exposure to antimicrobial therapy) within the host. The contribution of these changes warrants further investigation.

MALDI-TOF mass spectrometry: An emerging tool for unequivocal identification of non-fermenting Gram-negative bacilli

BACKGROUND & OBJECTIVES

Matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) has been instrumental in revolutionizing microbiological identification, especially in high-throughput laboratories. It has enabled the identification of organisms like non-fermenting Gram-negative bacilli (NFGNB), which has been a challenging task using conventional methods alone. In this study an attempt was made to validate MALDI-TOF MS for the identification of clinical isolates of each of the three most common NFGNB, other than Pseudomonas spp., taking molecular methods as the gold standard.

METHODS

One hundred and fifty clinical isolates of NFGNB, confirmed by molecular methods such as Acinetobacter baumannii[oxa-51 polymerase chain reaction (PCR)], Burkholderia cepacia complex (expanded multilocus sequence typing) and Stenotrophomonas maltophilia (species-specific PCR), were taken. Isolated colonies from fresh cultures of all 150 isolates were smeared onto ground steel plate, with and without formic acid extraction step. The identification was carried out using MALDI-TOF MS Biotyper database.

RESULTS

A concordance of 100 and 73.33 per cent was found between the molecular techniques and MALDI-TOF MS system in the identification of these isolates up to genus and species levels, respectively. Using a cut-off of 1.9 for reliable identification, rate of species identification rose to 82.66 per cent. Principal component analysis dendrogram and cluster analysis further increased discrimination of isolates.

INTERPRETATION & CONCLUSIONS

Our findings showed MALDI-TOF MS-based identification of NFGNB as a good, robust method for high-throughput laboratories.

Development of an Sce-I mutagenesis system for Burkholderia cepacia complex strains

The Burkholderia cepacia complex (Bcc) consists of at least 20 phenotypically similar but genotypically distinct Gram-negative bacteria that are ubiquitous in nature, are capable of promoting plant growth and biodegradation of pollutants, but that also are highly antibiotic resistant and produce damaging effects towards plants, fungi, and humans. To study these genetically recalcitrant bacteria in detail, molecular tools are required that work efficiently with the many strains and species of the Bcc. One mutagenesis strategy that has been used effectively to analyze the genes of Burkholderia cenocepacia is based upon the activity of the Sce-I restriction enzyme. Unfortunately, this system is limited in its applicability to many members of the Bcc. Therefore, we undertook the expansion of this system to create an Sce-I mutagenesis system that could be used with many different species and strains of the Bcc, including members of the B. cenocepacia IIIB Midwest clones. We demonstrated the use of this system by clean-deleting the lipo-oligosaccharide (LOS) inner core biosynthesis gene waaC, to create a B. cenocepacia PC184 strain variant with truncated LOS. This enhanced mutagenesis system can be used to analyze a wide range of Burkholderia and other Gram-negative bacteria.

Disseminated Pyomyositis Due to Burkholderia cepacia: A Case Report

Pyomyositis is a tropical infection affecting skeletal muscles manifesting as high-grade fever with pain in the affected limbs usually caused by Gram-positive microorganisms. Gram-negative organisms causing pyomyositis is uncommon but has been reported. Burkholderia cepacia is a Gram-negative nonfermenter causing opportunistic infections in immunocompromised patients, has been reported to cause pyomyositis only once before. We report a case of B. cepacia pyomyositis in a patient with no history of immunocompromised status, manifesting as disseminated infection with hemophagocytic syndrome presenting to our intensive care unit.

Macrophages, but not neutrophils, are critical for proliferation of Burkholderia cenocepacia and ensuing host-damaging inflammation

Bacteria of the Burkholderia cepacia complex (Bcc) can cause devastating pulmonary infections in cystic fibrosis (CF) patients, yet the precise mechanisms underlying inflammation, recurrent exacerbations and transition from chronic stages to acute infection and septicemia are not known. Bcc bacteria are generally believed to have a predominant extracellular biofilm life style in infected CF lungs, similar to Pseudomonas aeruginosa, but this has been challenged by clinical observations which show Bcc bacteria predominantly in macrophages. More recently, Bcc bacteria have emerged in nosocomial infections of patients hospitalized for reasons unrelated to CF. Research has abundantly shown that Bcc bacteria can survive and replicate in mammalian cells in vitro, yet the importance of an intracellular life style during infection in humans is unknown. Here we studied the contribution of innate immune cell types to fatal pro-inflammatory infection caused by B. cenocepacia using zebrafish larvae. In strong contrast to the usual protective role for macrophages against microbes, our results show that these phagocytes significantly worsen disease outcome. We provide new insight that macrophages are critical for multiplication of B. cenocepacia in the host and for development of a fatal, pro-inflammatory response that partially depends on Il1-signalling. In contrast, neutrophils did not significantly contribute to disease outcome. In subcutaneous infections that are dominated by neutrophil-driven phagocytosis, the absence of a functional NADPH oxidase complex resulted in a small but measurably higher increase in bacterial growth suggesting the oxidative burst helps limit bacterial multiplication; however, neutrophils were unable to clear the bacteria. We suggest that paradigm-changing approaches are needed for development of novel antimicrobials to efficiently disarm intracellular bacteria of this group of highly persistent, opportunistic pathogens.

Genomics Reveals a Unique Clone of Burkholderia cenocepacia Harboring an Actively Excising Novel Genomic Island

Burkholderia cenocepacia is a clinically dominant form among the other virulent species of Burkholderia cepacia complex (Bcc). In the present study, we sequenced and analyzed the genomes of seven nosocomial Bcc isolates, five of which were isolated from the bloodstream infections and two isolates were recovered from the hospital setting during the surveillance. Genome-based species identification of the Bcc isolates using a type strain explicitly identified the species as B. cenocepacia. Moreover, single nucleotide polymorphism analysis revealed that the six isolates were clonal and phylogenetically distinct from the other B. cenocepacia. Comparative genomics distinctly revealed the larger genome size of six clonal isolates as well as the presence of a novel 107 kb genomic island named as BcenGI15, which encodes putative pathogenicity-associated genes. We have shown that the BcenGI15 has an ability to actively excise from the genome and forming an extrachromosomal circular form suggesting its mobile nature. Surprisingly, a homolog of BcenGI15 was also present in the genome of a clinical isolate named Burkholderia pseudomallei strain EY1. This novel genetic element is present only in the variants of B. cenocepacia and B. pseudomallei isolates suggesting its interspecies existence in the main pathogenic species of the genus Burkholderia. In conclusion, the whole genome analysis of the genomically distinct B. cenocepacia clinical isolates has advanced our understanding of the epidemiology and evolution of this important nosocomial pathogen as well as its relatives.

Community Acquired Burkholderia cepacia Bacteraemia Presenting as MODS in an Immunocompetent Individual: An Unusual Case

Burkholderia cepacia has been recognized as a group of highly virulent organisms known as Burkholderia cepacia complex (Bcc). Bcc are ubiquitous in nature and most commonly found in moist environment, on plant roots and soil. Because of its high intrinsic antibiotic resistance, Bcc is a major cause of morbidity and mortality in hospitalized patients. It is reported most commonly in immunocompromised patients especially in patients with cystic fibrosis. Here, we report a rare case report of bacteraemia by Burkholderia cepacia in an immunocompetent male, who presented with fever and Multiple Organ Dysfunction Syndrome (MODS). Burkholderia cepacia was isolated from his blood culture, which he acquired from his work place. He was treated successfully and discharged after negative blood culture.

Community-acquired urinary tract infections caused by Burkholderiacepacia complex in patients with no underlying risk factor

Introduction. Urinary tract infections (UTIs) remain common infections diagnosed in outpatients as well as hospitalized patients. Community-acquired UTIs are generally caused by Escherichia coli and other members of the family Enterobacteriaceae.Burkholderiacepacia is an opportunistic pathogen mainly affecting immunocompromised and hospitalized patients, particularly those who have received prior broad-spectrum antibacterial therapy.

Case presentation. Urine samples were collected from 157 outpatients clinically diagnosed with UTI and from 100 healthy control subjects. Samples were cultured on differential media and non-motile lactose-non-fermentors were identified via the Remel RapID ONE system. The isolates were tested by the disc diffusion method against 17 antimicrobial agents. Burkholderia was isolated as a single organism from four patients having uncomplicated infections, and one from recurrent infection. None of these patients had an underlying risk factor for this pathogen. Identification of these isolates by the Remel-RapID ONE system was confirmed by recA gene amplification. The four isolates were resistant to lincomycin, nalidixic acid, oxacillin and penicillin G. These cases received monotherapy of oral co-trimoxazole.

Conclusions. Our findings alert urologists and diagnostic laboratories to the potential of B.cepacia complex infections in similar cases, and that this bacterium should not be ruled out.

Exploring the Role of the Ω-Loop in the Evolution of Ceftazidime Resistance in the PenA β-Lactamase from Burkholderia multivorans, an Important Cystic Fibrosis Pathogen

The unwelcome evolution of resistance to the advanced generation cephalosporin antibiotic, ceftazidime is hindering the effective therapy of Burkholderia cepacia complex (BCC) infections. Regrettably, BCC organisms are highly resistant to most antibiotics, including polymyxins; ceftazidime and trimethoprim-sulfamethoxazole are the most effective treatment options. Unfortunately, resistance to ceftazidime is increasing and posing a health threat to populations susceptible to BCC infection. We found that up to 36% of 146 tested BCC clinical isolates were nonsusceptible to ceftazidime (MICs ≥ 8 μg/ml). To date, the biochemical basis for ceftazidime resistance in BCC is largely undefined. In this study, we investigated the role of the Ω-loop in mediating ceftazidime resistance in the PenA β-lactamase from Burkholderia multivorans, a species within the BCC. Single amino acid substitutions were engineered at selected positions (R164, T167, L169, and D179) in the PenA β-lactamase. Cell-based susceptibility testing revealed that 21 of 75 PenA variants engineered in this study were resistant to ceftazidime, with MICs of >8 μg/ml. Under steady-state conditions, each of the selected variants (R164S, T167G, L169A, and D179N) demonstrated a substrate preference for ceftazidime compared to wild-type PenA (32- to 320-fold difference). Notably, the L169A variant hydrolyzed ceftazidime significantly faster than PenA and possessed an ∼65-fold-lower apparent K_i (K_iapp) than that of PenA. To understand why these amino acid substitutions result in enhanced ceftazidime binding and/or turnover, we employed molecular dynamics simulation (MDS). The MDS suggested that the L169A variant starts with the most energetically favorable conformation (-28.1 kcal/mol), whereas PenA possessed the most unfavorable initial conformation (136.07 kcal/mol). In addition, we observed that the spatial arrangement of E166, N170, and the hydrolytic water molecules may be critical for enhanced ceftazidime hydrolysis by the L169A variant. Importantly, we found that two clinical isolates of B. multivorans possessed L169 amino acid substitutions (L169F and L169P) in PenA and were highly resistant to ceftazidime (MICs ≥ 512 μg/ml). In conclusion, substitutions in the Ω-loop alter the positioning of the hydrolytic machinery as well as allow for a larger opening of the active site to accommodate the bulky R1 and R2 side chains of ceftazidime, resulting in resistance. This analysis provides insights into the emerging phenotype of ceftazidime-resistant BCC and explains the evolution of amino acid substitutions in the Ω-loop of PenA of this significant clinical pathogen.

Multilocus sequence analysis reveals high genetic diversity in clinical isolates of Burkholderia cepacia complex from India

Burkholderia cepacia complex (Bcc) is a complex group of bacteria causing opportunistic infections in immunocompromised and cystic fibrosis (CF) patients. Herein, we report multilocus sequence typing and analysis of the 57 clinical isolates of Bcc collected over the period of seven years (2005-2012) from several hospitals across India. A total of 21 sequence types (ST) including two STs from cystic fibrosis patient's isolates and twelve novel STs were identified in the population reflecting the extent of genetic diversity. Multilocus sequence analysis revealed two lineages in population, a major lineage belonging to B. cenocepacia and a minor lineage belonging to B. cepacia. Split-decomposition analysis suggests absence of interspecies recombination and intraspecies recombination contributed in generating genotypic diversity amongst isolates. Further linkage disequilibrium analysis indicates that recombination takes place at a low frequency, which is not sufficient to break down the clonal relationship. This knowledge of the genetic structure of Bcc population from a rapidly developing country will be invaluable in the epidemiology, surveillance and understanding global diversity of this group of a pathogen.

Burkholderia cepacia Complex Vaccines: Where Do We Go from here?

Burkholderia comprises a wide variety of environmental Gram-negative bacteria. Burkholderia cepacia complex (Bcc) includes several Burkholderia species that pose a health hazard as they are able to cause respiratory infections in patients with chronic granulomatous disease and cystic fibrosis. Due to the intrinsic resistance to a wide array of antibiotics and naturally occurring immune evasion strategies, treatment of Bcc infections often proves to be unsuccessful. To date, limited work related to vaccine development has been performed for Bcc pathogens. In this review, we have gathered key aspects of Bcc research that have been reported in recent years related to vaccine efforts, virulence, immune responses, and animal models, and use this information to inform the research community of areas of opportunity toward development of a viable Bcc vaccine.

Outbreak of Burkholderia cepacia complex bacteremia in a chemotherapy day care unit due to intrinsic contamination of an antiemetic drug

BACKGROUND

In the end of 2009, a large number of patients with cancer undergoing chemotherapy at the day care unit of a private hospital in Mumbai, India developed Burkholderia cepacia complex (BCC) blood stream infection (BSI).

OBJECTIVE

The objectives were to identify the source of the outbreak and terminate the outbreak as rapidly as possible.

MATERIALS AND METHODS

All infection control protocols and processes were reviewed. Intensive training was started for all nursing staff involved in patient care. Cultures were sent from the environment (surfaces, water, air), intravenous fluids, disinfectants and antiseptics and opened/unopened medication.

RESULTS

A total of 13 patients with cancer with tunneled catheters were affected with BCC BSI. The isolates were of similar antimicrobial sensitivity. No significant breach of infection control protocols could be identified. Cultures from the prepared intravenous medication bags grew BCC. Subsequently, culture from unused vials of the antiemetic granisetron grew BCC, whereas those from the unopened IV fluid bag and chemotherapy medication were negative. On review, it was discovered that the outbreak started when a new brand of granisetron was introduced. The result was communicated to the manufacturer and the brand was withdrawn. There were no further cases.

CONCLUSIONS

This outbreak was thus linked to intrinsic contamination of medication vials. We acknowledge a delay in identifying the source as we were concentrating more on human errors in medication preparation and less on intrinsic contamination. We recommend that in an event of an outbreak, unopened vials be cultured at the outset.

Non-oral gram-negative facultative rods in chronic periodontitis microbiota

OBJECTIVE

The subgingival prevalence of gram-negative facultative rods not usually inhabiting or indigenous to the oral cavity (non-oral GNFR), as well as selected periodontal bacterial pathogens, were evaluated by culture in untreated and treated chronic periodontitis patients.

METHODS

Subgingival biofilm specimens from 102 untreated and 101 recently treated adults with chronic periodontitis in the Netherlands were plated onto MacConkey III and Dentaid selective media with air-5% CO2 incubation for isolation of non-oral GNFR, and onto enriched Oxoid blood agar with anaerobic incubation for recovery of selected periodontal bacterial pathogens. Suspected non-oral GNFR clinical isolates were identified to a species level with the VITEK 2 automated system.

RESULTS

A total of 87 (42.9%) out of 203 patients yielded subgingival non-oral GNFR. Patients recently treated with periodontal mechanical debridement therapy demonstrated a greater prevalence of non-oral GNFR (57.4% vs 28.4%, P < 0.0001), and a greater number of different non-oral GNFR species (23 vs 14 different species), than untreated patients. Sphingomonas paucimobilis was the most frequently isolated subgingival non-oral GNFR species. Several GNFR species normally found in animals and human zoonotic infections, and not previously detected in human subgingival biofilms, were recovered from some patients, including Bordetella bronchispetica, Pasteurella canis, Pasteurella pneumotropica and Neisseria zoodegmatis. Porphyromonas gingivalis and Tannerella forsythia were significantly associated with the presence of subgingival non-oral GNFR.

CONCLUSIONS

A surprisingly high proportion of Dutch chronic periodontitis patients yielded cultivable non-oral GNFR in periodontal pockets, particularly among those recently treated with periodontal mechanical debridement therapy. Since non-oral GNFR species may resist mechanical debridement from periodontal pockets, and are often not susceptible to many antibiotics frequently used in periodontal practice, their subgingival presence may complicate periodontal treatment in species-positive patients and increase risk of potentially dangerous GNFR infections developing at other body sites.

Burkholderia Sepsis in Children as a Hospital-Acquired Infection

PURPOSE

Hospital-acquired Burkholderia cepacia (B. cepacia) infection are not commonly recorded in patients without underlying lung disease, such as cystic fibrosis and chronic granulomatous disease. However, in 2014, B. cepacia appeared more frequently in pediatric blood samples than in any other year. In order to access this situation, we analyzed the clinical characteristics of B. cepacia infections in pediatric patients at our hospital.

MATERIALS AND METHODS

We conducted a retrospective study of blood isolates of B. cepacia taken at our hospital between January 2004 and December 2014. Patient clinical data were obtained by retrospective review of electronic medical records. We constructed a dendrogram for B. cepacia isolates from two children and five adult patients.

RESULTS

A total of 14 pediatric patients and 69 adult patients were identified as having B. cepacia bacteremia. In 2014, higher rates of B. cepacia bacteremia were observed in children. Most of them required Intensive Care Unit (ICU) care (12/14). In eleven children, sputum cultures were examined, and five of these children had the same strain of B. cepacia that grew out from their blood samples. Antibiotics were administered based on antibiotic sensitivity results. Four children expired despite treatment. Compared to children, there were no demonstrative differences in adults, except for history of ICU care.

CONCLUSION

Although there were not many pediatric cases at our hospital, awareness of colonization through hospital-acquired infection and effective therapy for infection of B. cepacia is needed, as it can cause mortality and morbidity.

Burkholderia cepacia Exit-Site Infection in Peritoneal Dialysis Patients-Clinical Characteristics and Treatment Outcomes

♦

BACKGROUND

Burkholderia cepacia is a hardy bacterium with intrinsic resistance to multiple antibiotics and high transmissibility. Opportunistic healthcare-associated B. cepacia infections among immunocompromised or critically ill patients have been reported, but there is limited data on the clinical characteristics and treatment outcomes of exit-site infection (ESI) in peritoneal dialysis (PD) patients. ♦

PATIENTS AND METHODS

Patients who suffered from B. cepacia ESI from 1 January 2004 to 31 December 2014 were reviewed. The clinical characteristics and treatment outcomes of the patients and the antibiotic susceptibility patterns of the bacterial isolates were analyzed. ♦

RESULTS

Twenty-two patients were included for analysis. Eight patients (36.4%) had medical conditions which impaired host immunity, while 7 (31.8%) had pre-existing skin abnormalities. Three patients (13.6%) progressed to tunnel-tract infection and another 3 patients (13.6%) developed associated peritonitis. Fifteen patients (68.2%) responded to medical treatment while 7 (31.8%) required catheter removal. Eleven patients (50.0%) had recurrent B. cepacia ESI, which occurred at 7.8 months (95% confidence interval [CI] 0.1 - 19.4 months) after the first episode. Most B. cepacia strains were susceptible to ceftazidime (95.5%), piperacillin/tazobactam (95.5%), and piperacillin (90.9%). Besides aminoglycosides (80 - 100%), high rates of resistance were also observed for ticarcillin/clavulanate (90.9%). ♦

CONCLUSION

Burkholderia cepacia ESI is associated with low rates of tunnel-tract infection or peritonitis, but the risk of recurrence is high. Most cases can be managed with medical treatment alone, although one third of patients might require catheter removal.

Clinical and in vitro evidence for the antimicrobial therapy in Burkholderia cepacia complex infections

Treatment of infections caused by Burkholderia cepacia complex (Bcc) in cystic fibrosis (CF) patients poses a complex problem. Bcc is multidrug-resistant due to innate and acquired mechanisms of resistance. As CF patients receive multiple courses of antibiotics, susceptibility patterns of strains from CF patients may differ from those noted in strains from non-CF patients. Thus, there was a need for assessing in vitro and clinical data to guide antimicrobial therapy in these patients. A systematic search of literature, followed by extraction and analysis of available information from human and in vitro studies was done. The results of the analysis are used to address various aspects like use of antimicrobials for pulmonary and non-pulmonary infections, use of combination versus monotherapy, early eradication, duration of therapy, route of administration, management of biofilms, development of resistance during therapy, pharmacokinetics-pharmacodynamics correlations, therapy in post-transplant patients and newer drugs in Bcc-infected CF patients.

Burkholderia cepacia sepsis among neonates

Burkholderia cepacia is a rare cause of sepsis in newborns and its transmission involves human contact with heavily contaminated medical devices and disinfectants. The authors aimed to determine epidemiology, clinical features, antibiotic sensitivity pattern, complications and outcome of blood culture proven B. cepacia infections in 12 neonates. All neonates were outborn, 5 preterm and 7 term. B. cepacia was isolated from blood in all and concurrently from CSF in three neonates. Lethargy and respiratory distress (41.7 %) were major presenting features. Five newborns (41.7 %) required mechanical ventilation for 3-7 d. Highest bacterial susceptibility was observed for meropenem (100 %), followed by cefoperazone-sulbactam, piperacillin-tazobactam, sulfamethoxazole-trimethoprim (all 83 %), ceftazidime (75 %) and ciprofloxacin (42 %). Piperacillin-tazobactam, ciprofloxacin and cotrimoxazole either singly or in combination led to complete recovery of 11 (91.7 %) newborns; one developed hydrocephalus. Eight of nine infants who completed 6 mo follow up were normal. Prompt recognition and appropriate antibiotic therapy for B. cepacia infection results in complete recovery in majority.