Comamonas Testosteroni Emerging Gastrointestinal
Pathogen
M V Dharsandia1, Charmi Khanpara1, A K Sadikot2, C H Kansagra2, K K Rawal2
1Department of Microbiology,
Sciences, Rajkot, Gujrat
ABSTRACT:
2Department of Gastroenterology , Prime Institute of Digestive
Comamonas testosteroni newly emerging microorganism previously known as Pseudomonas
testosteroni is common environmental bacterium that is not known to be a part of the human commensal
organism. Since its identification as a human pathogen in 1987, numerous reports have drizzled in,
implicating this organism for various infections. Comamonas testosteroni are rare isolates in
microbiology laboratories and have been infrequently reported as an infectious agent in routine clinical
practice. Comamonas testosteroni has been rarely observed as an infectious agent in clinical practice.
Comamonas testosteroni is rarely recognized as a human pathogen. Most of the reported cases are
bloodstream infections. We report this pathogen from the stool of an immunocompromised 48-year-old
male. The aim of this case report is to alert clinicians and laboratory physicians for the potential
diagnosis and clinical approach of gastrointestinal infections caused by this organism.
KEYWORDS: comamonas testosterone; gram negative organism; gastrointestinal.
Address for correspondence : Dr M.V. Dharsandia, Infection control Officer & Microbiologist, Prime Hospital, Near Chandresh Vadi,
Laxinagar, Rajkot - 360005, E-mail: drmilankumar@gmail.com
Submitted: 09.06.2023, Accepted: 14.06.2023, Published: 26.06.2023
INTRODUCTION:
Comamonas testosteroni belong to the genus
Comamonas, family Comamonadaceae, which are
betaprotebacteria in the pseudomonas rRNA
homology group III[1]. Comamonas testosteroni is
aerobic, gram-negative non-fermenting bacterium.
They were first discovered in 1894, and since then, 24
species have been characterized. Bacterial species,
including Ralstonia spp, Ochrobactrun spp,
Pseudomonas aeruginosa , Sphingomonas
paucimobilis, and Brevundimonas spp, all belong to
this group[2,3,4,5,6].
The natural habitat of these bacteria is soil,
wastewater/sludge, fresh water such as ponds and
rivers and the animal intestinal flora. They have also
been isolated from the hospital environment and
clinical samples, such as urine, pus, blood, tissue,
stool, and respiratory secretions of cystic fibrosis
patients[7]. Comamonas testosteroni is thought to be of
low virulence. They have, however, caused infections,
including serious infection such as septicemia or
endocarditis in immunocompetent hosts. Herewith, we
present a case of Comamonas testosteroni associated
from stool.
CASE REPORT:
A 46 years old chronic smoker & tobacco
chewer male from urban area was admitted to tertiary
care hospital for chronic alcoholic liver disease with
acute chronic pancreatitis due to recent alcohol intake.
The chief complaint was high grade fever since 5-6
days, difficulty in breathing since last 1-2 hrs, diarrhea
& abdominal pain since 1-2 days.
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74 People’s Journal of Scientific Research / Volume 16 / Issue 1 / Jan-June 2023
How to cite this article: Dharsandia MV, Khanpara C, Sadikot AK,
Kansagra CH, Raval KK. Comamonas Testosteroni Emerging
Gastrointestinal Pathogen. PJSR. 2023;16(1):74-76.
Case Report
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DOI:
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Laboratory Investigation:
Routine examination showed patient blood
pressure was 160/80 mmHG, pulse rate 160/min.
Central nervous system, cardiovascular system
appeared normal. Abdominal examination revealed
tenderness in left epigastria & left hypochondria.
Other relevant laboratory finding suggested
hemoglobin 9 g/dl, decreased white blood cell count
C o l i s t i n , C e f t a z i d i m e ,
A z t r e o n a m ,
Ciprofloxacin, Levofloxacin and Trimethoprim-
Sulfamethoxazole. Blood culture of the same patient
remained sterile for 7 days of incubation. Therapy was
changed to Gentamicin 4 mg/kg/dose daily and
imipenem 25 mg/kg/dose 8 hourly for 10 days. The
patient responded well to antibiotic therapy.
5,240
mm3 (neutrophil
84%,
lymphocyte
11%),
platelet count within normal limit. The serological
tests for human immunodeficiency virus, hepatitis B
virus surface antigen, and hepatitis C virus were all
non-reactive. CRP was dramatically raised to 223.6
mg/L. Stool & Blood culture was sent to the
microbiology laboratory.
Radiological finding:
Ultrasonography revealed cholecystitis and
small amount of fluid noted in peripancreatic area.
Patient was given empirical therapy with fluid and
electrolyte replacement and kept on piperacillin-
tazobactam & Vancomycin as empirical antibiotic
treatment.
Laboratory workup:
Blood Culture was kept in BacT/ALERT/3D
automated blood culture system by Biomerieux for 7
days of incubation. Stool culture streaking was done
on MacConkey agar, 5% sheep blood agar & XLD agar
plate. Other relevant hematological investigation were
also performed.
Findings:
In stool culture, after overnight incubation on
MacConkey agar, colonies were non-lactose
fermenting, small translucent, smooth & without
pigment (Figure 1). Sheep blood agar plate showed
non-hemolytic, non-pigmented colonies similar as on
MacConkey agar. Colonies were Oxidase positive,
Catalase positive, Gram negative and motile in
hanging drop preparation (Figure 2). They were than
processed for identification and sensitivity by Vitek-2
compact by Biomerieux using GN and N406 for
identification and sensitivity respectively. It was
identified as Comamonas testosteroni with 99%
probability. It was found sensitive to Gentamicin,
Amikacin, Imipenem, Meropenem, Piperacillin-
Tazobactum, Cefoperazone-sulbactum, Cefepime and
Minocycline. And it was found resistant to Ofloxacin,
Figure 1 : Colonies of Comamonas testosteroni on MacConkey agar.
Figure 2 : Colonies of Comamonas testosteroni on Sheep blood agar.
DISCUSSION:
Comamonas testosteroni are ubiquitously
found in nature and have a global distribution. Intra-
abdominal infections are the commonest infections
reported with this organism[8]. Most of the previously
reported cases were immunocompromised due to
different condition. Our case was also immunoco-
mpromised due to alcoholic chronic liver disease
leading to chronic pancreatitis. Comamonas
testosteroni is the most common species among its
various species causing human infection and majority
People’s Journal of Scientific Research / Volume 16 / Issue 1 / Jan-June 2023 75
Dharsandia MV et al. Comamonas Testosteroni: An Gastrointestinal Pathogen
76
People’s Journal of Scientific Research / Volume 16 / Issue 1 / Jan-June 2023
of the patients were survived. Intra-abdominal
infections are the most common infections caused by
Comamonas testosterone, especially in individuals
with predisposing conditions[9]. Bacterial translocation
from gastrointestinal tract seems to play an important
role in the pathogenesis caused by Comamonas
species. Comamonas species are inherent and are able
to survive in environment which makes it suitable
candidate for chronic and mild infection[9]. In our case
there was no specific source of infection identified.
Immunocompromised status of the patient plays a
major role in producing infection by this organism.
One incidence of infection by Comamonas testosteroni
has been reported in stool culture in elderly women
with colostomy. The aim of this case report was to alert
clinicians and laboratory physicians about the
potential diagnosis and clinical approach of
gastrointestinal infections caused by this organism.
CONCLUSION:
We reported a rare case of Comamonas
testosterone associated with stool. This case highlights
a thorough clinical and laboratory work-up that is
necessary for a positive outcome.
ACKNOWLEDGMENT:
The authors are grateful to Ms. Sweta
Gaudana, Mr. Jigar Varsada, Ms.Rutu Dharsandia for
their contribution.
Financial Support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
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