A genomic and epidemiological study by scientists at the National Institutes of Health (NIH) has linked a small cluster of multidrug-resistant Sphingomonas koreensis infections at the NIH Hospital to the hospital's sanitation system. [19659002DieErgebnissederUntersuchungdiedieBesorgnisüberdasVorhandenseinvonKrankheitserregerninKrankenhäusernunddasRisikoderÜbertragungaufPatientenhervorhebterscheinenheuteimNewEnglandJournalofMedicine
The investigation was triggered in six patients in the NIH Clinical Center developed infections Sphingomonas – species that are ubiquitous in natural and artificial water sources were 201
In order to evaluate the genetic relationship of the isolates, the researchers carried out a sequencing of the entire genome (WGS). , They also received environmental samples from rinses in S koreensis patients and performed WGS and shotgun metagenome sequencing on the isolates to identify a potential reservoir in the hospital infrastructure. Previous studies have implicated contaminated hospital sinks in the transmission of carbapenem-resistant Enterobacteriaceae and Pseudomonas aeruginosa .
To determine whether isolates are unique to the NIH Clinical Center, researchers compared S koreensis isolates obtained from other institutions.
The study revealed that the four isolates from 19459003 S koreensis from 2016 had exceptionally high genetic similarity (> 99.92% average nucleotide identity) of the same clonal strain and were resistant to several antibiotics. In addition, the eight isolates from the year 2006 S koreensis showed similar values among themselves and with the isolates from 2016 (> 99.8% average nucleotide identity).
The researchers also found this 55 S koreensis isolates from taps and water samples from patient rooms were genetically similar to the clinical isolates of 2016 (> 99.7% average nucleotide identity), indicating the sinks or the water as most likely source of infection implied None of the clinical isolates could be perfectly matched to isolates from sinks in patient rooms. Clinical S koreensis isolates from other entities differed genetically from the NIH isolates.
Of the 12 patients, 9 received stem cell transplant recipients. Eight patients recovered and three died; One of the patients was found to be either colonized or contaminated with the bacterium. The three deceased patients also had severe, unrelated infections.
The researchers speculate that a single strain S koreensis invaded the water system shortly after the construction of a new NIH clinic center in 2004 and then the hospital was widely distributed. No further infections have been reported since the remedial measures were implemented in December 2016.
27. December N Engl J Med Summary