- InfezMed

Le Infezioni in Medicina, n. 1, 71-76, 2016
case report
71
Report of an immunocompetent
case with disseminated infection
due to Nocardia otitidiscaviarum:
Identification by 16S rRNA gene
sequencing
Esma Eren1, Aysegul Ulu-Kilic1, Altay Atalay2, Hayati Demiraslan1,
Omur Parkan2, Nedret Koc2
1
2
Erciyes University, Faculty of Medicine, Infectious Disease and Clinical Microbiology, Kayseri, Turkey;
Erciyes University, Faculty of Medicine, Medical Microbiology, Kayseri, Turkey
SummaRY
Nocardia otitidiscaviarum belongs to the agents of opportunistic infections seen in immunocompromised
patients, but may occur rarely in immunocompetent
patients. In this report we described a case of a previously healthy 69-year-old woman with cerebral and
retroperitoneal abscess due to Nocardia otitidiscaviarum.
The patient was admitted to hospital because of loss
of strength in her right arm and leg. Nocardia spp. was
isolated from the abscess material.
The intracranial lesions were drained by stereotactic
craniotomy. The large abscess located around the left
nINTRODUCTION
N
ocardiosis is an opportunistic infection
caused by Nocardia spp. which may present
with local (cutaneous, pulmonary) involvement
and may also be generalized with the involvement of several organs. Nocardiosis has been reported more frequently in patients with deficient
cell-mediated immunity such as found in AIDS,
solid organ or haematopoietic stem cell transplant, chronic obstructive pulmonary disease,
malignancies and cirrhosis. Long term steroid
Corresponding author
Aysegul Ulu-Kilic
E-mail: [email protected]
kidney was drained and microscopic examination of
aspirated material showed Nocardia spp. For species
identification, 16S rRNA gene sequencing was carried
out and was 100% concordant with Nocardia otitidiscaviarum. Use of 16S rDNA gene sequencing for identification permits detection of rare aetiologic agents that
cause brain abscesses.
Keywords: Nocardia otitidiscaviarum, disseminated nocardiosis, brain abcess, retroperitoneal abscess, 16S
rRNA gene sequencing.
therapy has also been found to be associated with
nocardiosis [1, 2].
Most human infections are caused by Nocardia
asteroides complex which consists of six species
including Nocardia abscessus, Nocardia brevicateana-paucivorans complex, Nocardia nova complex,
Nocardia transvalensis complex, Nocardia farcinica,
and Nocardia asteroides. Non-cutaneous invasive
forms and central nervous system (CNS) involvement of the disease are typically related to this
complex. Infections due to Nocardia otitidiscaviarum are uncommon (3%) when compared to
those caused by other Nocardia species. This low
incidence is associated with the reduced pathogenicity of N.otitidiscaviarum [3]. The most common presentation by N.otitidiscaviarum is pulmonary infection [4]. Here, we present a case with
72 E. Eren, et al.
intracranial and retroperitoneal abscess caused
by N.otitidiscaviarum in an immunocompetent patient.
nCASE REPORT
A 69-year-old female presented with loss of
strength in her right arm and leg for 10 days. Her
medical history was unremarkable; she lived in
a rural area and she had two dogs. On physical
examination, the findings were as follows: temperature was 38.7 oC, blood pressure was 110/70
mmHg, pulse rate was 84/min. Respiratory and
abdominal examinations were normal. Neurological examination of the patient revealed 3/5
strength in her right arm and leg. The results of
laboratory investigations were as follows: white
blood cell count was 12,0x103 /µL with 68% neutrophilic leucocytes, CRP was 138 mg/L, sedimentation was 33mm/h. All the blood cultures
were negative. Tests for HIV, hepatitis C virus,
hepatitis B surface and core antigens were negative. The CD4 lymphocyte count was 263/mm3.
Magnetic resonance imaging (MRI) of the brain
showed bilateral multiple hemispheric lesions:
the largest with a diameter of 35 mm x2,5 mm located in right parietal lobe with an intense edema
(Figure 1). Echocardiography and thoracic computed tomography were unremarkable. The patient was treated empirically with ceftriaxone 2g/
day and metronidazole 2g/day. The lesions were
sampled under the guidance of neuronavigation.
Figure 1 - Magnetic resonance imaging of the brain
showed multiple lesions on bilateral the cerebral
hemisphere, the largest was with a diameter of 35 mm
x2,5 mm.
Microscopic analysis of the abscess materials
yielded numerous polymorph nuclear leukocytes
and filamentous-branched gram positive rods
which stained positive with modified acid-fast
stain (Figure 2). Abdominal ultrasound revealed
a large lesion (130x90x80 mm) which was located
around the left kidney. The lesion was drained
and microscopic examination of the aspirated
Figure 2 - The abscess materials
stained positive with modified acidfast stain
Report of an immunocompetent case with disseminated infection due to Nocardia otitidiscaviarum 73
material was also compatible with Nocardia spp.
So the diagnosis was “disseminated Nocardiosis”
the empiric antibiotic therapy was changed to
meropenem 6g/day and amikacin 1g/day.
Microbiological investigation. Isolates were inoculated to sheep blood agar and Sabouraud dextrose
agar. White colonies which were roughtened and
protruded from the surface, grew after five days
of incubation at 35 oC in aerobic environments.
The isolated microorganism was compatible with
Nocardia. It was catalase-positive, oxydase-negative, lysozyme-positive and urease- positive.
DNA sequence analysis of clinical isolates using
special laboratory equipment (RefGen) was accomplished using an ABI 3100 Genetic Analyzer
(Applied Biosystems, USA). The sequencing data
were analyzed using the BLAST system of the
“National Center for Biotechnology Information
(Bethesda, USA)” and these data had 100% concordance with Nocardia otitidiscaviarum.
According to antibiotic susceptibility test results, the isolates were found to be resistant to
cefotaxime (MIC >32 mg/L) and ampicillinsulbactam(MIC >256 mg/L), and were found to
be sensitive to amikacin (MIC =0.25 mg/L ), imipenem (MIC =0.25 mg/L), linezolid (MIC =0.50
mg/L)
and
trimethoprim-sulfamethoxazole
(TMP/SMX).
Figure 3 - Magnetic resonance imaging (MRI) of the
brain after completion of therapy.
After three weeks of antimicrobial therapy, control
MRI showed that the lesions sizes had increased.
Antimicrobial therapy was changed to intravenous meropenem (6g/day) and trimetroprim
(720mg/day)/sulfamethoxazole (3600mg/day).
The lesions were drained by stereotactic craniotomy once a week consecutively for three weeks.
Dural repair was performed after the drainage
was completed. Intravenous medical treatment
was continued for 8 weeks and the patient was
discharged with only oral trimetophrim-sulfamethoxazole. After 4 weeks, at the control examination, CRP was 3 mg/L. Treatment was continued for 1 year and control MRI showed the regression of the lesions (Figure 3).
nDISCUSSION
Nocardiosis is known as an opportunistic infection; the disease may occur rarely in immunocompetent patients. N.otitidiscaviarum is a relatively
a rare cause of nocardiosis because of its low
pathogenicity. Sytemic or disseminated disease is
defined if two or more organs of the body are involved. Previously, disseminated infections were
reported in cases with underlying malignancies,
AIDS, organ transplantation, prolonged glucocorticoid therapy, chronic granulomatous disease
[5]. In our case we reported the occurrence of
systemic nocardiosis with CNS and retroperitoneal involvement due to N.otitidiscaviarum in an
immunocompetent patient. Although her HIV
test result was negative the fact that the CD4 lymphocyte count of the patient was low at 263/mm3
may have contributed to the onset of infection.
A similar case was reported with multiple brain
abscesses and CD4 lymphocytopenia recently [6].
Therefore, low CD4 lymphocyte count may be a
predisposing factor for disseminated nocardiosis.
The lower respiratory tract represents the most
common site of infection in patients with nocardiosis. However, initial pulmonary focus usually cleared spontaneously, whereby the clinical
symptoms of metastatic infections appearing first
[1, 7]. In our patient, the symptoms of CNS infection were foreground; however the CNS involvement due to N.otitidiscaviarum is extremely rare.
Only 12 cases with brain abscess were reported
previously; three out of these were immuncompetent (Table 1) [7, 8].
74 E. Eren, et al.
Table 1 - Epidemiological characteristics, localization, predisposing factors, treatment and outcome of patients
with brain abscesses due to N. otitidiscaviarum from 1974 to 2014
Age,
Sex
Sites of Infection
Causey et al. [16]
54,M
CNS
Brain tumor
Ampicillin (NA)
No
-
F
Arroyo et al. [17]
45,M
CNS,
disseminated
Renal tumor
Sulfadiazine (14),
Streptomycin (11),
Minocycline(4),
Gentamicin(4)
No
-
F
Bradsher et al. [18]
63,M
CNS
No
TMP/SMX and
Minocycline (NA)
Yes
Excision
F
Talwar et al. [19]
50,F
CNS
No
TMP/SMX and
Gentamicin (NA)
Yes
Excision
F
Perez et al. [20]
31,F
CNS
HIV, drug
abuser
Ciprofloxacin (30),
Teicoplanin (30),
Rifampicin (30),
TMP/SMX (20),
Netilmicin (20)
No
-
F
Hartmann et al. [21]
50,F
CNS and
pulmonary
system
Renal
transplantation
Meropenem (42),
Rifampicin (102),
Ciprofloxacin (60)
Yes
Aspiration
S
Duran et al. [3]
21,M
CNS
Drug abuser
Imıpenem (45)
and TMP/SMX (45 days
iv and 6 months orally)
Yes
Excision
S
HemmersbachMiller et al. [14]
44,M
CNS and Soft
tissue
Renal
transplantation
and Diabetes
mellitus
TMP/SMX (120),
Amikacin (27),
Metronidazole (27)
Yes
Aspiration
F
Lim et al. [22]
68,M
CNS
Diabetes
mellitus and
head injury
Meropenem (70),
Amikacin (70) ,
TMP/SMX (75 days iv
and 12 months orally)
Yes
Aspiration
and Excision
S
Bonnet et al. [23]
71,M
CNS and
pulmonary
system
Diabetes
mellitus
Vancomycin (46),
Ceftazidime (46),
Gentamicin (46)
No
-
F
Pelaez et al. [2]
85,F
CNS and
pulmonary
system
COPD,
coronary
disease,
hypertension
TMP/SMX (17),
Imipenem (10),
Linezolid (7)
No
-
F
Ishihara et al. [8]
79,F
CNS
No
Meropenem (7),
panipenem/
betamipron (7),
sulbactam/
ampicillin (14),
cefozopran(14),
TMP/SMX(34)
Yes
Aspiration
S
Present
69,F
CNS and
retroperitoneal
abscess
No
Meropenem (77),
Amikacin (21),
TMP/SMX (56 days iv
and 10 month orally)
Yes
Aspiration
S
Case
Underlying
Disease
Choice and duration (days)
of antimicrobial therapy
Surgery
Type of Surgical
Operation
Prognosis
M:Male/ F:Female, F: Fatal/S: Survived, CNS: Central Nervous System, TMP/SMX: Trimethoprim/ sulfamethoxazole, NA: Not Accessible
Report of an immunocompetent case with disseminated infection due to Nocardia otitidiscaviarum 75
N. otitidiscaviarum is known as a potentially zoonotic pathogen. The bacterium was first recognized in a guinea pig with an ear infection and
N. otitidiscaviarum is a pathogenic species for dogs
[2,9,10]. Our patient was a dog owner, without
any evidence of infection in her dogs. Despite the
occurrence of infection in various animals, the
transmission of the disease from animals to humans has not been documented yet.
Nocardia spp. grow in non-selective media and the
diagnostic yield is increased by the use of selective media such as Thayer-Martin agar. N. otitidiscaviarum has an ability to hydrolyze both hypoxanthine and xanthine is different from that of
other species of Nocardia [4]. Colonial characteristics and cellular morphology are variable, and
Nocardia spp. may be misidentified and confused
with members of closely related genera. However, these techniques are laborious, time-consuming, and expensive and can take 1 to 3 weeks to
accomplish. Sequence analysis of the 16S rRNA
gene represents the gold standard to identify the
species of Nocardia isolated [2].
The mainstay treatment for nocardial infections
is antimicrobial therapy. Trimethoprim-sulfamethoxazole is the first choice of treatment especially for localized and mild forms of nocardiosis.
It achieves high tissue concentrations in the lungs,
brain, skin and bone. An imipenem and amikacin
combination is suggested as initial therapy in cerebral nocardiosis and in the severely ill patients;
however, even if in cerebral localization imipenem/cilastatin and amikacin combination are
more effective than TMP/SMX, these combination can cause severe renal failure and deafness [1,
7]. Third generation cephalosporins such as ceftriaxone and cefotaxime are useful for brain abscess;
they have excellent CNS penetration, but in our
case N.otitidiscaviarum was found to be resistant
to 3rd generation cephalosporins [11]. Combined
treatment with amikacin also failed. Treatment
was continued with TMP-SXT and meropenem.
Isolates were sensitive to imipenem, but meropenem was the drug of choice because of the possible side effects of imipenem, such as convulsion.
Meropenem has fewer side-effects than imipenem, has better penetration into the tissues and
blood-brain barrier, and more active against
N.otitidiscaviarum. In a multicenter study from
Taiwan, 8 N.otitidiscaviarum isolates were 100%
resistant to imipenem and 100% sensitive to ami-
kacin, sulfamethoxazole and linezolid. Also, according to MIC values, meropenem was found
more active than imipenem [12].
Nocardia abscesses may resemble brain tumors
such as astrocytoma, metastasis and lymphoma.
Stereotactic aspiration of the abscess is recommended for diagnosis, specific microbiological
identification and anti-microbial sensitivity. For
lesions larger than 2.5 cm in diameter surgical
aspiration is recommended. Craniotomy and excision are reserved for lesions that enlarge after
two weeks or fail to shrink after four weeks of
antibiotic treatments [13]. Although the mortality
of N. otitidiscaviarum brain abcess is high as 75%,
reported cases with favorable outcome were treated with antibiotics combined with surgical procedures (Table 1) [14]. The recommended treatment
for nocardial brain abscesses is high dose intravenous antibiotics for 3 to 6 weeks and then oral
treatment for 12 months [15].
nCONCLUSION
Infection by N. otitidiscaviarum is uncommon because of its low pathogenicity. Immunosuppression is the most important risk factor for nocardiosis but it may rarely occur in immunocompetent
patients. Use of 16S rDNA gene sequencing for
identification may allow us to determine rare etiologic agents properly such as N.otitidiscaviarum
that cause brain abscess. Antimicrobial therapy
combined with surgical procedures represents an
optimal treatment of brain abscess due to N. otitidiscaviarum.
Conflict of interest: We confirm that there is no
conflict of interest related to this article.
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