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Case Reports
. 2019 Apr 23;19(1):334.
doi: 10.1186/s12879-019-3985-4.

Nosocomial bloodstream infection and the emerging carbapenem-resistant pathogen Ralstonia insidiosa

Qingqing Fang  1   2 , Yu Feng  1   2 , Ping Feng  1 , Xiaohui Wang  3   4 , Zhiyong Zong  1   2   5
Affiliations
Case Reports

Nosocomial bloodstream infection and the emerging carbapenem-resistant pathogen Ralstonia insidiosa

Qingqing Fang et al. BMC Infect Dis. .

Abstract

Background: Ralstonia picketti, Ralstonia mannitolilytica, and Ralstonia insidiosa have recently been regarded as emerging pathogens of infectious diseases, in particular as the pathogens responsible for nosocomial infection in immunocompromised patients. R. insidiosa differs from R. picketti and R. mannitolilytica, and its related infections are rarely reported.

Methods: Clinical data from two nosocomial bloodstream infection cases were extracted and analyzed. The causable isolates were identified by the VITEK 2 Compact system, matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), and molecular identification methods using PCR with universal and species-specific primers. Antimicrobial susceptibility testing was performed using the broth microdilution method. Both of the isolates were subjected to whole genome sequencing using a HiSeq X10 Sequencer. Antimicrobial resistance genes, virulence factors, and plasmid replicons were identified from assembled genomes. A real-time RT-PCR experiment and a cloning experiment were conducted to explore the related class D β-lactamase-encoding genes.

Results: Both patients recovered under therapy with antibiotics. Isolates were initially misidentified as R. mannitolilytica by the VITEK 2 Compact system rather than R. insidiosa, as identified by both MALDI-TOF MS and 16S rRNA gene sequencing. Both isolates were resistant to aminoglycosides, β-lactams, and polymyxin B. One isolate harboring blaOXA-570 was resistant to carbapenems. The whole genome sequencing data confirmed species identification based on average nucleotide identity (ANI) and revealed two variants of class D β-lactamase-encoding gene blaOXA (blaOXA-573 and blaOXA-574). The real-time RT-PCR experiment showed no difference in gene expression between blaOXA-570 and blaOXA-573 in our strains. The cloning experiment showed that variant OXA-573 had no carbapenem hydrolase activity.

Conclusions: We described two cases of nosocomial bloodstream infection caused by R. insidiosa strains. MALDI-TOF MS was cost-effective for rapid species identification. Clinicians should be aware that R. insidiosa can be resistant to commonly used antibiotics, even carbapenems.

Keywords: Bloodstream infections; Carbapenem-resistant; Nosocomial infection; Ralstonia insidiosa; Whole genome sequencing.

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Conflict of interest statement

Ethics approval and consent to participate

This study was approved by the Ethics Committee of West China Hospital, Sichuan University with a waiver of consent because the medical records and bacterial isolates used in this study were obtained from previous routine clinical activities. The committee deemed that exempting informed consent would not adversely affect the rights or health of the patients.

Consent for publication

Written informed consent has been acquired from the patients for the publication of this manuscript and all information contained herein.

Competing interests

The authors declare that they have no competing interests.

Publisher’s Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Figures

Fig. 1
Fig. 1
Phylogenetic tree based on core genome SNP. The tree was inferred using the maximum likelihood method under the GTRGAMMA model with a 1000-bootstrap test. Support values are colored based on confidence at internal nodes
Fig. 2
Fig. 2
Comparative analysis among R. insidiosa genomes of our isolates and previously published strains ATCC 49129 and FC1138
See this image and copyright information in PMC

References

    1. Ryan MP, Adley CC. Ralstonia spp.: emerging global opportunistic pathogens. Eur J Clin Microbiol Infect Dis. 2014;33:291–304. doi: 10.1007/s10096-013-1975-9. - DOI - PubMed
    1. Chen YY, Huang WT, Chen CP, Sun SM, Kuo FM, Chan YJ, et al. An outbreak of Ralstonia pickettii bloodstream infection associated with an intrinsically contaminated normal saline solution. Infect Control Hosp Epidemiol. 2017;38:444–448. doi: 10.1017/ice.2016.327. - DOI - PubMed
    1. Coenye T, Goris J, De Vos P, Vandamme P, LiPuma JJ. Classification of Ralstonia pickettii-like isolates from the environment and clinical samples as Ralstonia insidiosa sp. nov. Int J Syst Evol Microbiol. 2003;53:1075–1080. doi: 10.1099/ijs.0.02555-0. - DOI - PubMed
    1. Ryan MP, Pembroke JT, Adley CC. Genotypic and phenotypic diversity of Ralstonia pickettii and Ralstonia insidiosa isolates from clinical and environmental sources including high-purity water. Diversity in Ralstonia pickettii. BMC Microbiol. 2011;11:194. doi: 10.1186/1471-2180-11-194. - DOI - PMC - PubMed
    1. CLSI. Performance Standards for Antimicrobial Susceptibility Testing. 28th ed. CLSI supplement M100. Pennsylvania: Clinical and Laboratory Standards Institute; 2017.

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