Dataset Information

Methods for detecting Gemmata spp. bacteremia in the microbiology laboratory.

ABSTRACT:

Objective

Gemmata bacteria are fastidious, Gram-negative and aerobic. The only representatives are Gemmata obscuriglobus and Gemmata massiliana. These Planctomycetes appear to be a part of human digestive tract microbiome, and G. massiliana has been isolated from water. Further specific detection in the blood of two patients with febrile neutropenia suggests that Gemmata bacteremia may remain under-documented. The objective of this study was to develop an effective protocol to document Gemmata spp. bacteremia in the laboratory. Using mock-infected and control blood specimens, three methods for detecting Gemmata bacteremia, namely, automated microbial detection, culture on solid medium, and quantitative polymerase chain reaction (PCR), have been developed and studied.

Results

Gemmata spp. were undetected by automated blood culture system but culturing mock-infected blood on Caulobacter agar detected ≥ 10² G. obscuriglobus bacteria/mL and ≥ 10⁴ G. massiliana bacteria/mL. Specific real-time PCR detected 10² Gemmata bacteria/mL. These protocols may be used to investigate the epidemiology of Gemmata spp. bacteremia.

SUBMITTER: Christen JR

PROVIDER: S-EPMC5759251 | biostudies-literature | 2018 Jan

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Methods for detecting Gemmata spp. bacteremia in the microbiology laboratory.

Christen Jacques-Robert JR Edmond Edwin E Drancourt Michel M

BMC research notes 20180108 1

<h4>Objective</h4>Gemmata bacteria are fastidious, Gram-negative and aerobic. The only representatives are Gemmata obscuriglobus and Gemmata massiliana. These Planctomycetes appear to be a part of human digestive tract microbiome, and G. massiliana has been isolated from water. Further specific detection in the blood of two patients with febrile neutropenia suggests that Gemmata bacteremia may remain under-documented. The objective of this study was to develop an effective protocol to document G ...[more]

PMID: 29310696

Similar Datasets

Project description:Background:Planctomycetes bacteria are known to be difficult to isolate, we hypothesized this may be due to missing iron compounds known to be important for other bacteria. We tested the growth-enhancement effect of complementing two standard media with Escherichia coli culture filtrate on two cultured strains of Gemmata spp. Also, the acquisition of iron by Gemmata spp. was evaluated by measuring various molecules involved in iron metabolism. Materials and Methods:Gemmata obscuriglobus and Gemmata massiliana were cultured in Caulobacter and Staley's medium supplemented or not with E. coli culture filtrate, likely containing siderophores and extracellular ferrireductases. We performed iron metabolism studies with FeSO4, FeCl3 and deferoxamine in the cultures with the E. coli filtrate and the controls. Results and Discussion:The numbers of G. obscuriglobus and G. massiliana colonies on Caulobacter medium or Staley's medium supplemented with E. coli culture filtrate were significantly higher than those on the standard medium (p < 0.0001). Agar plate assays revealed that the Gemmata colonies near E. coli colonies were larger than the more distant colonies, suggesting the diffusion of unknown growth promoting molecules. The inclusion of 10-4 to 10-3 M FeSO4 resulted in rapid Gemmata spp. growth (4-5 days compared with 8-9 days for the controls), suggesting that both species can utilize FeSO4 to boost their growth. In contrast, deferoxamine slowed down and prevented Gemmata spp. growth. Further studies revealed that the complementation of Caulobacter medium with E. coli culture filtrate and 10-4 M FeSO4 exerted a significant growth-enhancement effect compared with that obtained with Caulobacter medium supplemented with E. coli culture filtrate alone (p < 0.0122). Moreover, the intracellular iron concentrations in G. obscuriglobus and G. massiliana cultures in iron-depleted broth supplemented with the E. coli filtrate were 0.63 ± 0.16 and 0.78 ± 0.12 ?mol/L, respectively, whereas concentrations of 1.72 ± 0.13 and 1.56± 0.11 ?mol/L were found in the G. obscuriglobus and G. massiliana cultures grown in broth supplemented with the E. coli filtrate and FeSO4. The data reported here indicated that both E. coli culture filtrate and FeSO4 act as growth factors for Gemmata spp. via a potentiation mechanism.

Project description:Blood cultures are central to the management of patients with sepsis and bloodstream infection. Clinical decisions depend on the timely availability of laboratory information, which, in turn, depends on the optimal laboratory processing of specimens. Discrete event simulation (DES) offers insights into where optimization efforts can be targeted. Here, we generate a detailed process map of blood culture processing within a laboratory and use it to build a simulator. Direct observation of laboratory staff processing blood cultures was used to generate a flowchart of the blood culture laboratory pathway. Retrospective routinely collected data were combined with direct observations to generate probability distributions over the time taken for each event. These data were used to inform the DES model. A sensitivity analysis explored the impact of staff availability on turnaround times. A flowchart of the blood culture pathway was constructed, spanning labeling, incubation, organism identification, and antimicrobial susceptibility testing. Thirteen processes in earlier stages of the pathway, not otherwise captured by routinely collected data, were timed using direct observations. Observations revealed that specimen processing is predominantly batched. Another eight processes were timed using retrospective data. A simulator was built using DES. Sensitivity analysis revealed that specimen progression through the simulation was especially sensitive to laboratory technician availability. Gram stain reporting time was also sensitive to laboratory scientist availability. Our laboratory simulation model has wide-ranging applications for the optimization of laboratory processes and effective implementation of the changes required for faster and more accurate results.ImportanceOptimization of laboratory pathways and resource availability has a direct impact on the clinical management of patients with bloodstream infection. This research offers an insight into the laboratory processing of blood cultures at a system level and allows clinical microbiology laboratories to explore the impact of changes to processes and resources.

Dataset Information

Methods for detecting Gemmata spp. bacteremia in the microbiology laboratory.

Objective

Results

Publications

Methods for detecting Gemmata spp. bacteremia in the microbiology laboratory.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets