A comparison of two molecular methods for diagnosing leptospirosis from three different sample types in patients presenting with fever in Laos

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Author(s)

Woods, K

Nic-Fhogartaigh, C

Arnold, C

Boutthasavong, L

Phuklia, W

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Type

Journal Article

Abstract

OBJECTIVES: To compare two molecular assays (rrs qPCR vs. a combined 16SrRNA and LipL32 qPCR) on different sample types for diagnosing leptospirosis in febrile patients presenting to Mahosot Hospital, Vientiane, Laos. METHODS: Serum, buffy coat and urine samples were collected on admission, and follow up serum ∼10 days later. Leptospira spp. culture and microscopic agglutination tests (MAT) were performed as reference standards. Bayesian latent class modeling was performed to estimate sensitivity and specificity of each diagnostic test. RESULTS: 787 patients were included in the analysis: 4/787 (0.5%) were Leptospira culture positive, 30/787 (3.8%) MAT positive, 76/787 (9.7%) rrs qPCR positive and 20/787 (2.5%) 16SrRNA/LipL32 qPCR positive for pathogenic Leptospira spp. in ≥1 sample. Estimated sensitivity and specificity (with 95% confidence intervals [CI]) of 16SrRNA/LipL32 qPCR on serum (53.9% (33.3-81.8%); 99.6%(99.2-100%)), buffy coat (58.8% (34.4-90.9%); 99.9%(99.6-100%)) and urine samples (45.0% (27.0-66.7%); 99.6% (99.3-100%)) were comparable with those of rrs qPCR, except specificity of 16SrRNA/LipL32 qPCR on urine samples was significantly higher (99.6% (99.3-100%) vs. 92.5% (92.3-92.8%), p<0.001). Sensitivity of MAT (16% (95%CI: 6.3-29.4%)) and culture (25% (95%CI: 13.3-44.4%)) were low. Mean positive Cq values showed that buffy coat samples were more frequently inhibitory to qPCR than either serum or urine (p<0.001). CONCLUSIONS: Serum and urine are better samples for qPCR than buffy coat, and 16SrRNA/LipL32 qPCR performs better than rrs qPCR on urine. qPCR on admission is a reliable rapid diagnostic tool, performing better than MAT or culture, with significant implications for clinical and epidemiological investigations of this global neglected disease.

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Date Issued

2018-09-01

Date Acceptance

2017-10-18

Citation

Clinical Microbiology and Infection, 2018, 24 (9), pp.1017.e1-1017.e7

URI

http://hdl.handle.net/10044/1/53750

DOI

https://www.dx.doi.org/10.1016/j.cmi.2017.10.017

ISSN

1198-743X

Publisher

Elsevier

Start Page

1017.e1

End Page

1017.e7

Journal / Book Title

Clinical Microbiology and Infection

Volume

24

Issue

9

Copyright Statement

©
201
7
The
Authors.
Published
by
Elsevier
Ltd
on
behalf
of
European
Society
of
Clinical
Microbiology
and
Infectious
Diseases.
This
is
an
open
access
article
under
the
CC
BY
lice nse
(http
://creativecommons.org/
licenses/by/4.0/).
*
Corresponding
author
.
K.
Woods,
National
Infection
Service,
Public
Health
England,
London,
UK.
E-mail
address:
Kate.woods2@nhs.net
(K.
Woods).
Contents
lists
available
at
ScienceDirect
Clinical
Microbiology
and
Infe
ction
journal
homepage:
www.clinicalmicrobiologyandinfection.com
https://doi.org/1
0.
1
01
6/j.cmi.201
7
.
1
0.0
1
7
1
1
98-7
43X/©
20
1
7
The
A
uthors.
Published
by
Elsevier
Ltd
on
behalf
of
European
Society
of
Clinical
Microbiology
and
Infectious
Diseases.
This
is
an
open
access
article
under
the
CC
BY
license
(http://creativecommons.org/licenses/by/4.0/).

Identifier

PII: S1198-743X(17)30579-7

Subjects

Bayesian

Laos

Latent class model

Leptospira

Leptospirosis

buffy coat

molecular diagnosis

qPCR

serum

urine

Publication Status

Published

Date Publish Online

2017-10-26