Infection Control & Hospital Epidemiology (2019), 40, 252–253 doi:10.1017/ice.2018.314
Letter in Reply
Reusable blood collection tube holders are implicated in nosocomial hepatitis C virus transmission
Vincent C. C. Cheng MD1,2, Shuk-Ching Wong MNurs2, Sally C. Y. Wong FRCPath1, Siddharth Sridhar FRCPath3, Cyril C. Y. Yip PhD1, Jonathan H. K. Chen PhD1, James Fung MD4, Kelvin H. Y. Chiu MRCP1, Pak-Leung Ho MD3, Sirong Chen PhD5, Ben W. C. Cheng MHKCRRT(CNMR)5, Chi-Lai Ho MD5, Chung-Mau Lo MS6
and Kwok-Yung Yuen MD3 1Department of Microbiology, Queen Mary Hospital, Hong Kong Special Administrative Region, China, 2Infection Control Team, Queen Mary Hospital, Hong Kong West Cluster, Hong Kong Special Administrative Region, China, 3Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong
Kong, Hong Kong Special Administrative Region, China, 4Department of Medicine, Queen Mary Hospital, Hong Kong Special Administrative Region, China, 5Department of Nuclear Medicine & Positron Emission Tomography, Hong Kong Sanatorium and Hospital, Hong Kong Special Administrative Region, China and 6Department of Surgery, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China
To the Editor—In response to the letter by Tsang et al,1 we offer the following point-by-point rebuttal. Almost all hospital out- break investigations require direct observation of patient care practices that are confounded by the Hawthorne effect, leading to the underestimation of incorrect practices. Despite this limitation, our direct observation showed that our phlebotomists had not been trained to comply with 2 manufacturers’ instructions: (1) the need for disinfection of reusable blood collection tube holders (RBCTH) between every patient and (2) the release of tourniquet immediately after blood starts flowing into the specimen tube to minimize backflow.2–4 These noncompliant practices had been adopted by all phlebotomists since the introduction of RBCTH into Hong Kong public hospitals. The male source patient and the female victim were housed in
the same ward served by 1 or more phlebotomists. Our compu- terized barcoding system recorded 34 phlebotomists with 54 visits to this ward for all patients between August 6, 2017, and August 19, 2017. The same phlebotomist collected blood from the source patient before collecting blood from the female victim in the morning shift on August 9, 2017, (phlebotomist A) and on August 11, 2017 (phlebotomist B). Of 29 phlebotomists being interviewed, 28 reported the sole use of RBCTH kept in the ward’s phlebotomy trolley where the HCV-positive RBCTH was found, including those who provided services on August 9, 2017, and August 11, 2017. Because HCV remains infectious for 6 weeks in the environment, patients were at risk of exposure whether the same or different phlebotomists took blood from the victim before or after the source patient, as long as the HCV- contaminated RBCTH in this phlebotomy trolley was in use. Using this barcoding system, we reviewed an earlier case of nosocomially acquired HCV in a 94-year-old female (supple- mentary material online). A phlebotomist took blood from a
Author for correspondence: Kwok-Yung Yuen, Carol Yu Centre for Infection,
Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China. E-mail:
kyyuen@hku.hk Cite this article: Cheng VCC, et al. (2019). Reusable blood collection tube holders are
implicated in nosocomial hepatitis C virus transmission. Infection Control & Hospital Epidemiology 2019, 40, 252–253. doi: 10.1017/ice.2018.314
© 2019 by The Society for Healthcare Epidemiology of America. All rights reserved.
78-year-old female HCV-positive patient on April 7, 2016, and collected blood from this victim immediately afterward. Again, the RBCTH could have been the vector; extensive investigation did not identify any other modes of transmission. In addition to the RBCTH, only 1 glucometer and 1 phlebotomy
trolley in use could be sampled for HCV on December 5, 2017. Our direct observation showed no practice irregularities in venous catheter insertion or multiple-dose drug-vial sharing. The presence of HCV inside the RBCTH with high degree of sequence similarity to source patient and victim HCV isolates clearly demonstrated that the phlebotomists had used this RBCTH and that blood con- tamination inside this RBCTH had occurred. Combination with the information from our barcoding system, the possibility of both source and victim sharing this RBCTH has to be entertained. Until now, none of the reported HCV hospital outbreaks have
utilized whole-virus genome sequencing, although partial-genome quasi-species sequencing was advocated by Campo et al.5 Most previous reports used the hypervariable region (E1 and E2 HVR), with only 140 bp to 411 bp sequenced.6,7 Others have used the NS5b, with 328 bp sequenced.8 Only 1 study has evaluated environmental samples comparing 81 bp of HVR between patients and environmental samples. In this case-control study suggesting the sharing of multiple-dose heparin vial as the source, no HCV could be detected in these vials.9 Another case-control study using multivariate analysis showed that international nor- malized ratio (INR) monitoring by phlebotomy and podiatry were risk factors for HCV acquisition,10 and next-generation sequen- cing was used to analyze 291 bp of HVR quasi-species instead of the entire genome. In this study, <3% (9 bp) of the genome was used as evidence of clonality between HCV strains.10 Thus, none of the phylogenetic studies of HCV outbreak were as stringent as ours. With only 3 nucleotide positions of divergence of 653 bp (HVR) between the HCV sequences from the RBCTH, the source patient, and the victim, we thus confirmed clonality. As for the phlebotomy simulation experiments, we used only
HCV-positive plasma because no HCV-positive archived EDTA blood was available. Blood is denser andmore adhesive than plasma, which would lead to a larger volume of inoculum remaining on
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