Conclusion
Collectively, these results suggested that 9 of the 13 patients were infected with M. pneumoniae at the same time as SARS-CoV-2. These results were confirmed thrice using 2 specific ELISA
variants; capELISA and recELISA, and Western blotting. This is the first report in Tunisia enlightening the clinicians treating the COVID-19 patients about the possibility of co-infection with
other common respiratory pathogens, namely Mycoplasma pneumoniae. These findings should prompt further research examining the co-infection with M. pneumoniae in COVID-19
patients in Tunisia using large number, geographically diverse, and clinically well-defined sera.
Abstract
The coronavirus disease 2019 (COVID-19) is the most dramatic pandemic that affected the world since the 20th century. Apart from the severe acute respiratory syndrome coronavirus 2
(SARS-CoV-2) which is the principle etiological and causative agent of this disease, some studies have raised concerns towards co-infection with different fungal, viral, and bacterial agents in
COVID-19 patients. The aim of this study was to investigate the occurrence of the atypical respiratory pathogen, Mycoplasma pneumoniae, in a cohort of thirteen COVID-19 Tunisian
patients admitted to the intensive care unit of a regional hospital (south-eastern Tunisian capital).
Background
Given its extreme severity, rapid spread, and high rate of infection, COVID-19 is a global public health emergency. Compounded by ambiguities about the different clinical manifestations,
the COVID‐19 pandemic has caused increasing challenges for healthcare practitioners. Additionally, co-infection with other respiratory pathogens has the potential to aggravate the clinical
situation and make diagnosis, treatment, and prognosis more difficult. That is why this study is undertaken to evaluate the rate of co-infection with M. pneumoniae in COVID-19 patients in
Tunisia, using three serodiagnostic assays: crude antigen-based capture ELISA (capELISA), Western blotting, and recombinant antigen-based ELISA (recELISA).
Results
recELISA results showed a clear dominance in the
reactivity of the recombinant P1 type 2 with most
sera from patients with COVID-19.
NC PC PC' S1 S2 S3 S4 S5 S6 S7 S8 S9 S10 S11 S12 S13
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
Type 1 Type 2
OD
450
nm
Type1 Type2
0.0
0.2
0.4
0.6
0.8
DO
450
nm
P=0,0054
Distribution of the OD values (dots) of
tested sera in recELISA. All sera were
positive with the recombinant P1 type 1
and type 2 proteins. The horizontal lines
show the cut-off value.
C1 C2 S1 S2 S3 S4 S5 S6 S7 S8 S9 S10 S11 S12 S13
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
OD
450
nm
A: SDS-PAGE of the purified GST fusion
products GST-P1 type 1 (Lane 1) and GST-P1
type 2 (Lane 2). Lane M: Prestained Protein
Ladder. Lane GST: Unfused GST protein
A) B)
CapELISA reactivity of Mycoplasma pneumoniae (strains M129
and FH) whole cell-proteins with sera from COVID-19 patients
Purification and specificity of recombinant Mycoplasma
pneumoniae P1 adhesin type 1 and type 2
Concomitant infection with Mycoplasma pneumoniae and SARS-CoV-2 in Tunisian patients
Imen Chniba, Elhem Yacoub, Nadine Khadraoui, Safa Boujemaa, Béhija Mlik and Boutheina Ben Abdelmoumen Mardassi
Group of Mycoplasmas, Laboratory of Molecular Microbiology, Vaccinology, and Biotechnology Development, Institut Pasteur de Tunis,
Université Tunis El Manar, 13, Place Pasteur, BP 74, 1002, Tunis Belvédère, Tunisia
imen.chniba@hotmail.com
RecELISA reactivity of the positive sera in specific IgG against
M. pneumoniae with recombinant P1 type 1 and type 2 proteins
9 out 13 (69%) of the enrolled COVID-
19 patients were positive in specific
Mycoplasma pneumoniae IgG and 4 of
13 (31%) were negative.
B: Reactivity pattern of the polyclonal
antiseum raised against the recombinant
M. pneumoniae P1 proteins: GST-P1 type 1
(Lane 1) and GST-P1 type 2 (Lane 2). Lane
M: Prestained Protein Ladder. Lane GST:
Unfused GST protein
Western blot reactivity of Mycoplasma pneumoniae (strains M129 and FH)
whole cell-proteins with the 9 positive sera tested by capELISA
A: total proteins of M. pneumoniae strain M129 (ATCC 29342). B: total proteins of M. pneumoniae
strain FH (ATCC 15531). Lanes 1-13: Patient sera. C1: Positive control (serum from a patient
previously tested and confirmed positive for M. pneumoniae). C2: Positive control (rabbit polyclonal
anti-M. pneumoniae serum. C3: negative control (PBS buffer). M and M': molecular weight markers
(in Kilodaltons)
A)
B)
Type1 Type2
0.0
0.2
0.4
0.6
0.8
DO
450
nm
P=0,0054