|Year : 2020 | Volume
| Issue : 1 | Page : 44-46
Septic arthritis caused by Arcanobacterium haemolyticum with fatal outcome
AN Vimalraj1, Aiswarya Mukundan1, Greeshma Hareendranath2, PK Sreekumary3
1 Department of Microbiology, Government Medical College, Thrissur, Kerala, India
2 Department of Microbiology, Government T. D. Medical College, Alappuzha, Kerala, India
3 Department of Microbiology, Government Medical College, Kottayam, Kerala, India
|Date of Submission||07-Dec-2019|
|Date of Decision||30-Apr-2020|
|Date of Acceptance||25-May-2020|
|Date of Web Publication||13-Aug-2020|
Dr. Aiswarya Mukundan
“Harichandanam”, Chakkoth Lane, Punkunnam (P.O), Thrissur - 680 002, Kerala
Source of Support: None, Conflict of Interest: None
Arcanobacterium haemolyticum is a well-recognised cause of pharyngitis and skin and soft-tissue infections. It is often under-reported in microbiology laboratories probably because diphtheroids are commonly considered as colonizers or contaminants in bacterial cultures. A. haemolyticum usually cause infections in immunocompromised patients. Here, we present a case of septic arthritis in an immunocompetent individual. The purpose of this case report is to create increased awareness of the pathogenic potential of this organism in bone and joint infections.
Keywords: Arcanobacterium haemolyticum, Gram-positive bacilli, septic arthritis
|How to cite this article:|
Vimalraj A N, Mukundan A, Hareendranath G, Sreekumary P K. Septic arthritis caused by Arcanobacterium haemolyticum with fatal outcome. J Acad Clin Microbiol 2020;22:44-6
|How to cite this URL:|
Vimalraj A N, Mukundan A, Hareendranath G, Sreekumary P K. Septic arthritis caused by Arcanobacterium haemolyticum with fatal outcome. J Acad Clin Microbiol [serial online] 2020 [cited 2020 Sep 30];22:44-6. Available from: http://www.jacmjournal.org/text.asp?2020/22/1/44/291893
| Introduction|| |
Arcanobacterium haemolyticum is a commensal on human skin and the mucous membrane of the upper respiratory tract. It was first described in 1946 as a cause of throat and soft-tissue infection in US soldiers in the South Pacific. This organism was previously known as Corynebacterium haemolyticum. Based on chemical and phenotypic data, it was later included in the genus Arcanobacterium. It is now an established agent of pharyngitis, skin and soft-tissue infections. Systemic infections caused by this bacterium has rarely been reported. Only a few cases of septicaemia caused by A. haemolyticum smooth type have been published in patients with no underlying diseases. Arcanobacterium means 'mysterious bacterium', which is frequently misinterpreted as a contaminant or normal flora. We would, therefore, like to focus attention on its possible relevance as an infective agent in immunocompetent patients.
| Case Report|| |
A 50-year-old female presented to the emergency department with a history of pain and swelling in the right knee, fever, vomiting and dyspnoea of two weeks. She suffered from residual paralysis of both lower limbs following poliomyelitis. Mid-tarsal amputation was done for osteomyelitis 1 year back. On examination, the pulse rate was 120/mt and blood pressure was 102/62 mm Hg. Local examination showed edema, redness and local rise of temperature over the right knee. Haemoglobin - 9.6 g/dl; Total leucocyte count - 23,000 cells/mm 3 with polymorphs 55%, lymphocytes 40%, eosinophils 1%, basophils 2%, monocytes 2%. Platelet count – 90,000 cells/μl. Erythrocyte sedimentation rate (145 mm/h) and C-reactive protein (103 mg/dl) values were elevated.
Liver function tests, renal function tests and serum electrolytes were within the normal limits. Random blood sugar was 76 mg/dl.
X-ray of the right knee showed deformed knee with narrowing of joint space and soft-tissue swelling. She was put on ventilator support and started on empirical therapy with Piperacillin-Tazobactam (2.25 g intravenous twice daily) and Gentamicin (80 mg intravenous thrice daily) for two days. Arthrotomy was done and exuberant pus was drained, which was sent for culture and sensitivity.
Gram-staining showed pus cells along with slightly curved Gram-positive bacilli with no peculiar arrangement. Ziehl-Neelsen staining was negative for acid-fast bacilli. The pus was cultured on Blood agar, Chocolate agar and Mac Conkey agar. The plates were incubated at 37°C in 5% CO2. After 24 h of incubation, small, 0.5 mm sized nonpigmented colonies with a clear zone of complete haemolysis was obtained on Blood agar. There was pitting of the colonies on Blood agar. Gram-stained smear prepared from colonies on Blood agar showed Gram-positive bacilli with branching and Chinese letter arrangement. The organism was catalase, oxidase negative and nonmotile. It failed to grow on Tellurite blood agar; it did not hydrolyse urea. Glucose, lactose and sucrose were fermented with acid production but mannitol was not fermented. Nitrate was not reduced. The reverse CAMP test was positive. Blood culture was sterile.
A. haemolyticum was identified by its typical colony morphology, Gram stained features, catalase reaction (negative) and carbohydrate fermentation tests (glucose, lactose, sucrose, mannitol) and reverse CAMP test. Antibiotic susceptibility testing was performed and the isolate was found to be sensitive to Penicillin, Ampicillin, Erythromycin, Clindamycin, Ceftriaxone, Amoxicillin-Clavulanic acid, Ciprofloxacin, Gentamicin, Vancomycin and resistant to Cotrimoxazole. The confirmation of diagnosis was done by Matrix-Assisted Laser Desorption/Ionization-Time-Of-Flight (MALDI-TOF) (Bio Merieux) and API Coryne system (Bio Merieux). The antibiotic was changed to Vancomycin (800 mg intravenous thrice daily). However, the condition of the patient deteriorated and finally, she succumbed to death.
Predisposing factors/risk factors if any: Nil.
| Discussion|| |
A. haemolyticum is a Gram-positive, nonmotile and nonsporulating pleomorphic rod; coccal forms predominate in older cultures. Optimum growth is obtained on blood or serum enriched medium at 37°C and is enhanced by culturing the organism in the presence of 5% CO2. On human Blood agar, prominent haemolysis is seen within 24 h and pitting beneath the colonies is a useful feature for identification. Deep-seated infections such as brain abscesses, meningitis, septicaemia, infective endocarditis and osteomyelitis have been reported less frequently. Other mild infections include chronic skin ulcers, cellulitis and otitis media.
There are two distinct biotypes of A. haemolyticum: smooth and rough colonies on solid growth medium. Majority of the strains are smooth-type. The smooth-type is most commonly associated with wound infections while the rough type is isolated almost exclusively from respiratory specimens.
Out of the 15 cases of deep-seated infections with A. haemolyticum reported since 1998, bacteremia was confirmed by a positive blood culture only in seven of them. There were no blood cultures positive from our case as well. Majority of these cases had a skin lesion as the most likely source of bacteremia. The role of this organism in orthopaedic infections is not clearly established and is limited to a few reports. The various clinical presentations include chronic wound infection, ankle joint infection, foot ulcer and osteomyelitis. A case of septic arthritis in a patient with no co-morbidities has also been reported from India.
MALDI-TOF has been described as a good and very fast method for the identification of A. haemolyticum. 16S r RNA gene sequencing may also be used as a specific method of identification for A. haemolyticum compared to traditional culture methods.
There are no definitive guidelines available for the treatment of this infection. The various treatment options include Penicillins, Cephalosporins, Macrolides, Vancomycin, Fluoroquinolones, Clindamycin and Doxycycline. Trimethoprim/Sulfamethoxazole should be avoided if A. haemolyticum is suspected as the organism appears to be intrinsically resistant to this drug.
Few cases of caused by A. haemolyticum have been described. The pathogenic potential of diphtheroids is being recognised increasingly. Hence, we would like to emphasize the fact that proper identification and antibiotic sensitivity testing of all the aerobic nonspore forming Gram-positive bacilli obtained in pure culture from sterile sources is essential to initiate appropriate antibiotic therapy.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
We express our sincere gratitude to the Department of Microbiology, Kasturba Medical College, Manipal, for having helped us with MALDI-TOF and Vitek-2.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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