KEY CLINICAL MESSAGE
Blood cultures should be taken routinely in cases of polyarthritis. In
case of Listeria bacteremia, endocarditis should be investigated in
high-risk patients. Aminopenicillin and aminoglycoside remains the most
effective treatment for listeriosis.
INTRODUCTION
Listeria monocytogenes (LM) is a facultative intracellular Gram-positive
bacterium that causes listeriosis. Infection usually occurs through
ingestion of contaminated food, particularly shellfish, deli meats and
dairy products. The disease is relatively rare, with 0.1-10 cases per
million people per year depending on the country. Mortality is estimated
at 20-30% of infected patients [1].
Listeriosis mainly affects newborns, pregnant women, the elderly,
transplant and immunocompromised patients. It classically presents as
febrile gastroenteritis leading to bacteremia, which may be responsible
for meningoencephalitis or maternal-fetal infection [2].
Endocarditis and spondylodiscitis are rare forms [3,4]. We describe
a case of aortic bioprosthesis endocarditis associated with
spondylodiscitis due to LM.
OBSERVATION
A 75-year-old man was admitted to the Internal Medicine Department with
polyarthritis of the wrists, elbows, shoulders, hips, knees and ankles
for three weeks without fever. He did not have any alteration in his
general condition. In the past, he has had two episodes of infective
endocarditis, the last one dated two years ago due to Streptococcus
gallolyticus and complicated by a severe aortic insufficiency requiring
replacement with a biological valve prosthesis. He had a pacemaker and
was known to have atrial fibrillation and chronic alcoholism.
On admission, the physical examination revealed a right knee effusion,
bilateral pain in the first metatarsophalangeal joint, mechanical low
back pain and ecchymotic purpura on the dorsal side of feet. Cardiac
auscultation revealed no murmurs and the neurological examination was
normal.
C-reactive protein was elevated to 78 mg/L. Blood count, serum
creatinine, uric acid and calcium levels were normal. The immunological
work-up showed normal serum protein electrophoresis, rheumatoid factor
at 27.1 IU/mL and negativity of anti-nuclear and anti-CCP antibodies.
Serologies for hepatitis B, C, HIV and syphilis carried out as part of
the etiological work-up for polyarthritis were negative. Proteinuria was
0.44 g per 24 hours.
Ultrasound of the joints showed effusion in the right knee, left ankle
and subacromial bursa with synovitis of the first metatarsophalangeal
joints. The knee joint aspiration revealed sterile inflammatory fluid
(3600 leukocytes/mm3) with uric acid crystals.
Two blood cultures 48 hours apart were finally positive for LM serogroup
IIa. The urine was sterile.
Transoesophageal echocardiography (TEE) showed 5 mm vegetation on the
aortic bioprosthesis and abscess at the aorto-mitral trigone. The
fluorine-18 fluorodeoxyglucose positron emission tomography (18F-FDG
PET/CT) showed hypermetabolism of the aortic valve and hyperfixation of
the L5 vertebral body suggesting spondylodiscitis (Figure 1). Magnetic
resonance imaging of the spine confirmed L4-L5 spondylodiscitis without
spinal cord compression (Figure 2).
On the 7th day of hospitalisation, a right brachiofacial hemiparesis and
dysarthria occurred suddenly. The brain computed tomography showed
ischaemic hypodensity in the left superficial sylvian territory with
subarachnoid haemorrhage in the frontotemporal region (Figure 3).
Cerebrospinal fluid (CSF) examination revealed a clear fluid containing
less than one leukocyte per mm3 with normal
proteinorachia (0.39 g/L), normal glycorachia (0.54 g/L), negative
culture and viral panel.
The diagnosis of LM endocarditis on aortic bioprosthesis associated with
L4-L5 spondylodiscitis was made, complicated by an abscess of the
aorto-mitral trigone and a cerebral septic embolus. The patient was a
regular consumer of unpasteurised milk. The diagnosis of gouty
arthropathy was associated.
As soon as the blood cultures were positive, intravenous antibiotic
therapy with amoxicillin 150 mg/kg/24hrs for 6 weeks and gentamycin 4
mg/kg/24hrs for 2 weeks was started. Treatment was continued with
amoxicillin 75 mg/kg/24hrs orally for a further 6 weeks with the use of
a corset for the management of spondylodiscitis. Colchicine was added to
the treatment.
The evolution is marked by the regression of the inflammatory syndrome,
the disappearance of pain and joint effusions. The TEE performed at the
3rd week of treatment showed complete disappearance of vegetation,
absence of valve leakage and stabilisation of the abscess. At the 6th
week, transthoracic echocardiography showed that the abscess had
disappeared. The neurological evolution consisted of motor recovery and
the disappearance of the haemorrhage on the brain scan. At 3 months,
X-rays of the lumbosacral spine showed a reconstitution process at the
L4-L5 level in favour of a favourable evolution of the spondylodiscitis.
DISCUSSION
The diagnosis of listeriosis is based on the isolation and
identification of LM from biological samples, including blood cultures
or CSF. Valvular and osteoarticular infections are unusual locations and
usually occur in special settings.
LM endocarditis occurs in 8% of patients with listeriosis [3]. It
can affect native or prosthetic valves and intracardiac devices. In
2017, 100 cases of LM endocarditis were identified in the MEDLINE
database [5]. The clinical manifestations are protean, fever is
often absent and vascular phenomena are very frequent. Aortic
involvement is most common in native valve endocarditis and mitral
involvement in prosthetic valve endocarditis [5]. Although
listeriosis usually affects women, evidence shows that men are
frequently affected by LM endocarditis [6]. The main predisposing
factors are immunodeficiency, valve disease, prosthetic devices,
hypertrophic cardiomyopathy and a history of endocarditis. Our patient
had an aortic bioprosthesis, a pacemaker and two episodes of infective
endocarditis. The context of chronic alcoholism was an important factor.
The absence of hypermetabolism on 18F-FDG PET/CT allowed us to rule out
a pacemaker infection.
LM is a rare causative agent of osteoarticular infection. The infection
usually affects a single joint with a predominance of the knee and hip.
It occurs in patients over 50 years of age with underlying diseases and
mainly concerns orthopaedic implants [7]. Rheumatoid arthritis,
osteoarthritis, liver cirrhosis and diabetes mellitus are the most
reported risk factors. Other authors have discussed the correlation of
LM ostearticular infection and surgical interventions [8]. Spinal
involvement is less common, resulting in spondylodiscitis. To our
knowledge, 7 cases of Listeria spondylodiscitis have been described in
the literature (Table 1) [4,9,10,11,12,13,14]. In some cases, the
diagnosis was confirmed by spinal biopsy. The association of LM
spondylodiscitis and endocarditis is reported in one case.
In our case, the neurological deficit was explained by the cerebral
septic embolus. During infective endocarditis, whatever the cause,
emboli are reported in 15-30% of cases, particularly affecting the
central nervous system [15]. In LM bacteremia, any neurological
involvement requires CSF analysis which was normal in our patient,
excluding meningoencephalitis. The association of LM endocarditis and
meningitis is exceptional in the literature [16].
The first-line treatment of listeriosis is based on the combination of
aminopenicillin and aminoglycoside which has a rapid synergistic
bactericidal activity [16,17]. The combination of ampicillin and
gentamycin is the most commonly used in LM endocarditis. The authors
suggest a treatment of 6 to 8 weeks for prosthetic valve endocarditis
and at least 4 weeks for native valve endocarditis [16,17]. Surgery
is often reserved for complicated cases [6]. In contrast, the
management of LM osteoarticular infections is still debated due to the
paucity of literature. Our patient received a total of 12 weeks of
treatment. In a 2012 study, no treatment failure was observed in
patients with the osteoarticular form without prosthetic devices treated
for a median of 15 weeks [7]. Other authors have shown the
effectiveness of rifampicin and cotrimoxazole [4,11]. Long-term
treatment with aminopenicillin remains a consensus.
Delayed diagnosis and treatment contribute to the fatal outcome of
patients. Valvular disease is one of the severe forms of listeriosis.
The mortality rate in LM endocarditis is significantly higher than in
other causes of bacterial endocarditis [18]. Prosthetic valve
involvement has higher morbidity and mortality rates compared to native
valve endocarditis, especially if associated with cardiac and cerebral
complications [19].
As initial symptomatology, our patient presented with a non-febrile
peripheral joint picture that is more consistent with the immunological
manifestation of endocarditis. This picture points in the first instance
to rheumatoid disease, which can delay the diagnosis in the absence of
fever. Our case reflects the importance of systematic blood cultures in
polyarthritis. The etiological research includes an inflammatory,
immunological, infectious (serologies and blood cultures), radiological
and joint aspiration work-up.
CONCLUSION
This is a case of LM endocarditis on bioprosthesis associated with
spondylodiscitis. The initial presentation is polyarthritis without
fever. Blood cultures should be performed routinely in such cases in
conjunction with an autoimmune work-up. In case of LM bacteremia,
patients at risk should be tested for endocarditis. The combination of
aminopenicillin and aminoglycoside is still the most effective treatment
for the usual and unusual forms of listeriosis.