Matrix-assisted laser desorption/ionization time-of-flight MS for the accurate identification of Burkholderia cepacia complex and Burkholderia gladioli in the clinical microbiology laboratory.

Introduction. Burkholderia cepacia complex (Bcc) bacteria, currently consisting of 23 closely related species, and Burkholderia gladioli, can cause serious and difficult-to-treat infections in people with cystic fibrosis. Identifying Burkholderia bacteria to the species level is considered important for understanding epidemiology and infection control, and predicting clinical outcomes. Matrix-assisted laser desorption/ionization time-of-flight MS (MALDI-TOF) is a rapid method recently introduced in clinical laboratories for bacterial species-level identification. However, reports on the ability of MALDI-TOF to accurately identify Bcc to the species level are mixed.Aim. The aim of this project was to evaluate the accuracy of MALDI-TOF using the Biotyper and VITEK MS systems in identifying isolates from 22 different Bcc species and B. gladioli compared to recA gene sequencing, which is considered the current gold standard for Bcc.Methodology. To capture maximum intra-species variation, phylogenetic trees were constructed from concatenated multi-locus sequence typing alleles and clustered with a novel k-medoids approach. One hundred isolates representing 22 Bcc species, plus B. gladioli, were assessed for bacterial identifications using the two MALDI-TOF systems.Results. At the genus level, 100 and 97.0 % of isolates were confidently identified as Burkholderia by the Biotyper and VITEK MS systems, respectively; moreover, 26.0 and 67.0 % of the isolates were correctly identified to the species level, respectively. In many, but not all, cases of species misidentification or failed identification, a representative library for that species was lacking.Conclusion. Currently available MALDI-TOF systems frequently do not accurately identify Bcc bacteria to the species level.

In Vitro Activity of Ceftolozane-Tazobactam and Other Antimicrobial Agents against Burkholderia cepacia Complex and Burkholderia gladioli.

We tested the activities of ceftolozane-tazobactam and 13 other antimicrobial agents against 221 strains of Burkholderia cepacia complex and Burkholderia gladioli Most strains (82%) were cultured from persons with cystic fibrosis, and most (85%) were recovered since 2011. The ceftolozane-tazobactam MIC was ≤8 µg/ml for 77% of the strains. However, the MIC range was broad (≤0.5 to >64 µg/ml; MIC50/90, 2/32 µg/ml). Significant differences in susceptibility to some antimicrobial agents were observed between species.

Burkholderia gladioli infection isolated from the blood cultures of newborns in the neonatal intensive care unit.

Burkholderia gladioli was described as a plant pathogen, and it is a rare cause of infection in humans that is primarily associated with human pulmonary infections, such as chronic granulomatous disease and cystic fibrosis. The neonatal respiratory system is not fully developed and cannot expel bacterial aerosol properly. A total of 2,676 newborns in the neonatal intensive care unit were retrospectively analysed in Putian City, Fujian Province, China, from 2011 to 2014. All of the blood samples were tested for C-reactive protein (CRP), procalcitonin (PCT) and white blood cell (WBC). B. gladioli infections were determined and analysed using a blood culture system. Antibiotic susceptibility testing was performed using the K-B method. Of the 2,676 participants, 87 (3.25 %) had a positive B. gladioli blood culture that occurred >72 h after birth, including a premature group (54.0 %, asphyxia [vs. 9.20 %], fever [vs. 13.80 %], pneumonia [vs. 6.90 %] and hyperbilirubinaemia [vs. 8.05 %]) and newborns with necrotising enterocolitis (NEC) (vs. 5.75 %). The mean ± standard deviation (SD) of the CRP level was 12.31 ± 0.26 mg/L and that of the PCT level was 1.53 ± 0.21 ng/ml in the 87 B. gladioli-infected newborns. Most of the B. gladioli isolates were sensitive to many antimicrobial agents and did not lead to serious consequences. All of the B. gladioli-infected newborns were unhealthy, especially the premature infants. B. gladioli might be a causative bacteraemia agent in neonates, it appears to have pathogenic potential in newborns and its sensitivity to antibiotics may be a beneficial factor.

Burkholderia gladioli sepsis in newborns.

UNLABELLED: Burkholderia gladioli is a rare cause of bacteremia and sepsis in the absence of such predisposing factors as chronic granulomatous disease, cystic fibrosis, and immunosuppression. Little is known about B. gladioli infection in newborns. The aim of this study was to present the features of B. gladioli infection in newborns. Clinicopathological characteristics, patterns of antimicrobial susceptibility, predisposing factors, and outcomes of B. gladioli bloodstream infection were retrospectively analyzed in newborns treated between 2008 and 2011. During the 3-year study period, B. gladioli was isolated from the blood cultures of 14 patients (3.7 per 1,000 admissions). In all, 5 (35.7 %) of the 14 cases had a positive blood culture at the time of initial admission. Primary diagnoses in the neonates were severe major congenital anomalies, congenital leukemia, prematurity with respiratory distress syndrome, pneumonia, and parapneumonic pleural effusion. In total, 10 (71.4 %) of the patients underwent ≥2 invasive procedures. The overall in-hospital mortality rate was 21.4 %, whereas the mortality rate due to B. gladioli infection was 7 %. CONCLUSION: B. gladioli might be a causative microorganism of both early neonatal and nosocomial sepsis in newborns. To the best of our knowledge, this is the first study on B. gladioli infection in newborns. Invasive procedures and severe major congenital anomalies may be predisposing factors for B. gladioli bloodstream infection in neonates. Although it appears to have low pathogenic potential and an insidious clinical course in newborns, resistance to antibiotics may be a potential problem. Mortality was primarily associated with underlying diseases.

Fatal Burkholderia gladioli infection misidentified as Empedobacter brevis in a lung transplant recipient with cystic fibrosis.

Data describing the risk of lung transplantation (LT), clinical features, and outcomes of patients with cystic fibrosis (CF) infected with Burkholderia gladioli are limited. Herein, we report a case of disseminated B. gladioli infection characterized by bacteremia, necrotizing pneumonia, lung abscess, and empyema in a lung transplant recipient with CF, highlight the importance of accurate microbiological identification, and review published outcomes of LT in CF patients infected with B. gladioli, which include cases of pneumonia, tracheobronchitis, bacteremia, and abscesses, and demonstrate an all-cause 1-year mortality of approximately 23%, often after combined medical and surgical treatment.

Microbiological and epidemiological features of clinical respiratory isolates of Burkholderia gladioli.

Burkholderia gladioli, primarily known as a plant pathogen, is involved in human infections, especially in patients with cystic fibrosis (CF). In the present study, the first respiratory isolates recovered from 14 French patients with CF and 4 French patients without CF, identified by 16S rRNA gene analysis, were tested for growth on B. cepacia selective media, for identification by commercial systems, and for their antimicrobial susceptibilities, and were compared by pulsed-field gel electrophoresis (PFGE). Patients' data were collected. All 18 isolates grew on oxidation-fermentation-polymyxin B-bacitracin-lactose medium and Pseudomonas cepacia agar, but only 13 grew on Burkholderia cepacia selective agar. API 20NE strips did not differentiate B. gladioli from B. cepacia, whereas Vitek 2 GN cards correctly identified 15 isolates. All isolates were susceptible to piperacillin, imipenem, aminoglycosides, and ciprofloxacin and were far less resistant to ticarcillin than B. cepacia complex organisms. Fifteen PFGE types were observed among the 18 isolates, but shared types were not identified among epidemiologically related patients. The microbiological follow-up of CF patients showed that colonization was persistent in 3 of 13 documented cases; B. gladioli was isolated from posttransplantation cultures of blood from 1 patient. Among the patients without CF, B. gladioli was associated with intubation (three cases) or bronchiectasis (one case). In summary, the inclusion of B. gladioli in the databases of commercial identification systems should improve the diagnostic capabilities of those systems. In CF patients, this organism is more frequently involved in transient infections than in chronic infections, but it may be responsible for complications posttransplantation; patient-to-patient transmission has not been demonstrated to date. Lastly, B. gladioli appears to be naturally susceptible to aminoglycosides and ciprofloxacin, although resistant isolates may emerge in the course of chronic infections.

Burkholderia gladioli: five year experience in a cystic fibrosis and lung transplantation center.

BACKGROUND: The impact of infection with Burkholderia gladioli in cystic fibrosis, other chronic airway diseases and immunosuppressed patients is unknown. METHODS: A six-year retrospective review of all patients with B. gladioli infection was performed in a tertiary referral center with cystic fibrosis and lung transplantation programs. In addition, a targeted survey of all 251 lung transplant recipients was performed. Available B. gladioli isolates were analyzed via pulsed field gel electrophoresis. RESULTS: Thirty-five patients were culture positive for B. gladioli, including 33 CF patients. No bacteremia was identified. Isolates were available in 18 patients and all were genetically distinct. Two-thirds of these isolates were susceptible to usual anti-pseudomonal antibiotics. After acquisition, only 40% of CF patients were chronically infected (> or =2 positive cultures separated by at least 6 months). Chronic infection was associated with resistance to > or =2 antibiotic groups on initial culture and failure of eradication after antibiotic therapy. The impact of acquisition of B. gladioli infection in chronic infection was variable. Three CF patients with chronic infection underwent lung transplantation. One post-transplant patient developed a B. gladioli mediastinal abscess, which was treated successfully. CONCLUSIONS: The majority of patients' culture positive for B. gladioli at our center have CF. B. gladioli infection is often transient and is compatible with satisfactory post-lung transplantation outcomes.

Burkholderia gladioli osteomyelitis in association with chronic granulomatous disease: case report and review.

We describe a case of insidious small bone osteomyelitis and soft tissue abscess with Burkholderia gladioli in a 6-year-old Caucasian boy with chronic granulomatous disease. DNA sequencing of the 16S ribosomal RNA gene confirmed the bacterial identification. Clinical cure was achieved with a combination of antimicrobial therapy and surgical debridement. A review of infections caused by Burkholderia spp., other than Burkholderia cepacia complex, in pediatric patients with chronic granulomatous disease is provided.

Outbreak of otitis media caused by Burkholderia gladioli infection in immunocompromised mice.

An athymic nude mouse with severe head tilt due to otitis media was identified. Within weeks of identification of this first case, immune-deficient mice of various genotypes from the same facility were similarly affected, and cases from other facilities were found within two months. Culture of ear exudate specimens from affected mice yielded bacteria that were initially identified as Burkholderia cepacia, a plant pathogen considered an important opportunistic pathogen in persons with cystic fibrosis or chronic granulomatous disease. Several of these isolates, however, were subsequently identified as B. gladioli on the basis of results of biochemical analysis and a species-specific polymerase chain reaction (PCR) assay. Genotyping analysis revealed clonality among the isolates, indicating a shared strain among affected mice. A 16S rDNA-based PCR assay specific for the genera Burkholderia and Ralstonia, and a selective culture medium were used in efforts to characterize the epidemiology of this outbreak. In addition to culture of specimens from the oropharyngeal cavity of affected mice, samples were obtained from the environment, feces, sipper tubes, drinking water, and soiled bedding from cages of affected individuals. Burkholderia gladioli was most consistently detected in oropharyngeal swab specimens from affected mice. The PCR assay was equivalent to selective culture in identifying mice in the carrier state that did not have clinical signs of infection. However, neither detection method had sufficient sensitivity to reliably identify all carrier mice, causing the organism to persist at low levels unless entire colonies of immune-deficient mice were removed. The organism was highly resistant to antibiotic therapy. The source and epidemiology of this organism remain unknown. This epizootic serves as an important reminder that immunocompromised rodent colonies may harbor important human opportunistic pathogens.