Polyclonal outbreak of bloodstream infections caused by Burkholderia cepacia complex in hematology and bone marrow transplant outpatient units

Global burden, point sources, and outbreak management of healthcare-associated Burkholderia cepacia infections: An integrative review

OBJECTIVE

To examine the global burden, associated point sources, and successful prevention and control measures for documented outbreaks of Burkholderia cepacia healthcare-associated infections (HAIs).

DESIGN

Integrative review.

METHODS

A review of all outbreaks of Burkholderia cepacia HAIs published in the peer-reviewed literature between January 1970 and October 2019 was conducted to identify the global burden, associated point sources, and successful prevention and control measures using the Guidelines for Outbreak Reports and Intervention Studies of Nosocomial Infections (ORION).

RESULTS

In total, we reviewed 125 documented outbreaks of Burkholderia cepacia-related HAIs worldwide. The reported B. cepacia HAIs for this period involved 3,287 patients. The point sources were identified in most outbreaks of B. cepacia HAIs (n = 93; 74.4%); they included medication vials, disinfectants, and antiseptics. Moreover, 95 of the outbreak reports (76%) described effective prevention and control measures, but only 33 reports indicated the use of a combination of environment-, patient- and staff-related measures. None of the outbreak reports used the ORION guidelines.

CONCLUSIONS

Outbreaks of Burkholderia cepacia HAIs are an ongoing challenge. They are often associated with immunocompromised patients who acquire the infection from exposure to contaminated medications, products, and equipment. These outbreaks are not infrequent, and a range of infection prevention and control measures have been effective in arresting spread. The use of ORION guidelines for outbreak reporting would improve the quality of information and data to generate evidence for translation into practice.

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.

Therapies for multidrug resistant and extensively drug-resistant non-fermenting gram-negative bacteria causing nosocomial infections: a perilous journey toward 'molecularly targeted' therapy

INTRODUCTION

Non-fermenting Gram-negative bacilli are at the center of the antimicrobial resistance epidemic. Acinetobacter baumannii and Pseudomonas aeruginosa are both designated with a threat level to human health of 'serious' by the Centers for Disease Control and Prevention. Two other major non-fermenting Gram-negative bacilli, Stenotrophomonas maltophilia and Burkholderia cepacia complex, while not as prevalent, have devastating effects on vulnerable populations, such as those with cystic fibrosis, as well as immunosuppressed or hospitalized patients. Areas covered: In this review, we summarize the clinical impact, presentations, and mechanisms of resistance of these four major groups of non-fermenting Gram-negative bacilli. We also describe available and promising novel therapeutic options and strategies, particularly combination antibiotic strategies, with a focus on multidrug resistant variants. Expert commentary: We finally advocate for a therapeutic approach that incorporates in vitro antibiotic susceptibility testing with molecular and genotypic characterization of mechanisms of resistance, as well as pharmacokinetics and pharmacodynamics (PK/PD) parameters. The goal is to begin to formulate a precision medicine approach to antimicrobial therapy: a clinical-decision making model that integrates bacterial phenotype, genotype and patient's PK/PD to arrive at rationally-optimized combination antibiotic chemotherapy regimens tailored to individual clinical scenarios.

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.

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

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