Respiratory tract samples, viral load, and genome fraction yield in patients with Middle East respiratory syndrome.
BACKGROUND
Analysis of clinical samples from patients with new viral infections is critical to confirm the diagnosis, to specify the viral load, and to sequence data necessary for characterizing the viral kinetics, transmission, and evolution. We analyzed samples from 112 patients infected with the recently discovered Middle East respiratory syndrome coronavirus (MERS-CoV).


METHODS
Respiratory tract samples from cases of MERS-CoV infection confirmed by polymerase chain reaction (PCR) were investigated to determine the MERS-CoV load and fraction of the MERS-CoV genome. These values were analyzed to determine associations with clinical sample type.


RESULTS
Samples from 112 individuals in which MERS-CoV was detected by PCR were analyzed, of which 13 were sputum samples, 64 were nasopharyngeal swab specimens, 30 were tracheal aspirates, and 3 were bronchoalveolar lavage specimens; 2 samples were of unknown origin. Tracheal aspirates yielded significantly higher MERS-CoV loads, compared with nasopharyngeal swab specimens (P = .005) and sputum specimens (P = .0001). Tracheal aspirates had viral loads similar to those in bronchoalveolar lavage samples (P = .3079). Bronchoalveolar lavage samples and tracheal aspirates had significantly higher genome fraction than nasopharyngeal swab specimens (P = .0095 and P = .0002, respectively) and sputum samples (P = .0009 and P = .0001, respectively). The genome yield from tracheal aspirates and bronchoalveolar lavage samples were similar (P = .1174).


CONCLUSIONS
Lower respiratory tract samples yield significantly higher MERS-CoV loads and genome fractions than upper respiratory tract samples.
Global Centre for Mass Gatherings Medicine and Ministry of Health, Riyadh, Kingdom of Saudi Arabia and College of Medicine, Alfaisal University.
Ziad A
ZA
Memish
Saudi Aramco Medical Services Organization, Dhahran Indiana University School of Medicine, Indianapolis.
Jaffar A
JA
Al-Tawfiq
Regional Laboratory, Ministry of Health Regional Laboratory, Ministry of Health Regional Laboratory, Ministry of Health, Madinah Regional Laboratory, Ministry of Health, Dammam, Kingdom of Saudi Arabia.
Hatem Q
HQ
Makhdoom
Global Centre for Mass Gatherings Medicine and Ministry of Health, Riyadh, Kingdom of Saudi Arabia and College of Medicine, Alfaisal University.
Abdullah
A
Assiri
Global Centre for Mass Gatherings Medicine and Ministry of Health, Riyadh, Kingdom of Saudi Arabia and College of Medicine, Alfaisal University.
Raafat F
RF
Alhakeem
Prince Sultan Military Medical City.
Ali
A
Albarrak
Pediatric Infectious Diseases, King Saud University, Riyadh.
Sarah
S
Alsubaie
Global Centre for Mass Gatherings Medicine and Ministry of Health, Riyadh, Kingdom of Saudi Arabia and College of Medicine, Alfaisal University.
Abdullah A
AA
Al-Rabeeah
Regional Laboratory, Ministry of Health Regional Laboratory, Ministry of Health Regional Laboratory, Ministry of Health, Madinah Regional Laboratory, Ministry of Health, Dammam, Kingdom of Saudi Arabia.
Waleed H
WH
Hajomar
Regional Laboratory, Ministry of Health Regional Laboratory, Ministry of Health Regional Laboratory, Ministry of Health, Madinah Regional Laboratory, Ministry of Health, Dammam, Kingdom of Saudi Arabia.
Raheela
R
Hussain
Regional Laboratory, Ministry of Health Regional Laboratory, Ministry of Health Regional Laboratory, Ministry of Health, Madinah Regional Laboratory, Ministry of Health, Dammam, Kingdom of Saudi Arabia.
Ali M
AM
Kheyami
Regional Laboratory, Ministry of Health Regional Laboratory, Ministry of Health Regional Laboratory, Ministry of Health, Madinah Regional Laboratory, Ministry of Health, Dammam, Kingdom of Saudi Arabia.
Abdullah
A
Almutairi
Special Infectious Diseases Agents Unit, King Fahad Medical Research Center, King Abdualziz University, Jeddah.
Esam I
EI
Azhar
Institute of Virology, University of Bonn Medical Center, Germany.
Christian
C
Drosten
Wellcome Trust Sanger Institute, Hinxton.
Simon J
SJ
Watson
Wellcome Trust Sanger Institute, Hinxton.
Paul
P
Kellam
Wellcome Trust Sanger Institute, Hinxton.
Matthew
M
Cotten
Global Centre for Mass Gatherings Medicine and Ministry of Health, Riyadh, Kingdom of Saudi Arabia and College of Medicine, Alfaisal University, Division of Infection and Immunity, University College London (UCL), and UCL Hospitals National Health Service Foundation Trust, United Kingdom.
Alimuddin
A
Zumla
D018352:Coronavirus Infections / Q000473:pathology* / Q000821:virology*; D006801:Humans; D065207:Middle East Respiratory Syndrome Coronavirus / Q000302:isolation & purification*; D016133:Polymerase Chain Reaction; D012137:Respiratory System / Q000821:virology*; D019562:Viral Load
Ct value; MERS-CoV; Middle East; RT-PCR; clinical; coronavirus; diagnosis; genome fraction; molecular; screening; viral load