![](images/Newspaper.gif)
Achromobacter xylosoxidans Subspecies denitrificans Endocarditis in a Patient with Prosthetic Aortic Valve: A Case Report and Review of Literature
Correspondence Address :
Dr. Chinmoy Sahu,
Department of Microbiology, C-block, Sanjay Gandhi Institute of Medical Sciences, Lucknow, Uttar Pradesh, India.
E-mail: csahu78@rediffmail.com
Achromobacter xylosoxidans subspecies denitrificans flourishes in presence of oxygen, commonly isolated from aquatic milieu. It is rarely implicated as the causative agent of endocarditis. It is not known to cause virulent infections in patients but causes severe infections in immunosuppressed patients with underlying co-morbidities. Present report is first case of Achromobacter xylosoxidans prosthetic valve endocarditis from India. This case report accounts for a 47-year-old man, suffering from Rheumatic Heart Disease (RHD), who presented to the cardiology emergency with chief complaints of remitting type high-grade fever for years years followed by persistent fever for 10 days. On echocardiography and positively flagged BACTEC blood culture reports was diagnosed as a case of Achromobacter xylosoxidans subspecies denitrificans bacteraemia and prosthetic aortic valve endocarditis. Antibiotics were started according to the susceptibility testing but the patient could not complete the course of treatment as he developed dyspnoea and cardiac arrest following which he could not be resuscitated.
Aortic regurgitation, Endocarditis, Immunocompromised patients, Matrix-assisted laser desorption/ ionization-time of flight-mass spectrometry, Mitral regurgitation, Rheumatic heart disease
A 47-year-old man who underwent prosthetic valve replacement surgery 18 years ago due to aortic regurgitation, presented to the cardiology emergency with chief complaints of remitting type high-grade fever for two years followed by persistent fever for 10 days. This patient was a follow-up case of RHD and infective endocarditis of prosthetic valve with chronic kidney disease, metabolic acidosis, and septic shock. His blood pressure was 107/60 mmHg, pulse rate was 96 beats/minute, and normal jugular venous pressure with metallic click sound of S1. Due to strong suspicion of valvular defect, he was advised for a two-dimensional echocardiography (2D-ECHO). His 2D-ECHO signs showed severe aortic and tricuspid valve regurgitation with moderate to severe mitral valve regurgitation and vegetations on the prosthetic aortic valve (Table/Fig 1)a-c. Three pairs of BACTEC bacterial cultures were sent to the Bacteriology Section of the Department of Microbiology within 24 hours to diagnose the causative pathogen (microbiological criteria) of Infective Endocarditis (IE). Two of the blood culture bottles flagged positive on the same day whereas the third bottle flagged positive the next morning. The microorganism isolated from all the blood culture bottles revealed growth of small pale-colored colonies on Mackonkey agar and non haemolytic colonies on blood agar (Table/Fig 2)a,b. Organism was recognised as Achromobacter xylosoxidans subspecies denitrificans by Matrix-Assisted Laser Desorption/ Ionisation-Time of Flight-Mass Spectrometry (MALDI-TOF-MS) assay. Kirby-Bauer disc diffusion method was used for performing antibiotic sensitivity testing which renders it susceptible to imipenem, meropenem, piperacillin- tazobactam, and cotrimoxazole. The patient was given the first two doses of intravenous piperacillin-tazobactam eight hourly for a day according to the antibiotic susceptibility but could not complete the course of treatment as he developed dyspnoea and underwent cardiac arrest on the same day before starting haemodialysis for chronic kidney disease. He was intubated for mechanical ventilation following cardiac arrest but despite all possible measures his blood pressure continued to fall and the patient went into cardiorespiratory arrest. Cardiopulmonary resuscitation procedures were performed as per protocol but the patient could not be resuscitated.
Achromobacter xylosoxidans subspecies denitrificans flourishes in presence of oxygen and is commonly isolated from aquatic milieu (1). It was acknowledged for the first time by Yabuuchi E and Oyama A in 1971, in pus samples obtained from ear infections in seven cases (2). This microorganism has been isolated as causative agent of central catheter infections, pneumonia, sepsis, meningitis, mediastinitis, and other hospital-acquired infections which may include outbreaks, but is rarely known to cause endocarditis (3),(4),(5).
Achromobacter xylosoxidans subspecies denitrificans stains negatively on Grams staining and is rarely implicated as the causative agent of endocarditis. Although it is known to cause several serious infections like sepsis, meningitis, and pneumonia, it rarely causes endocarditis (3),(4). It is not a highly virulent pathogen but immunocompromised patients are highly susceptible to the infections caused by them due to underlying co-morbidities and prosthetic valves (6),(7),(8).
The Duke criteria by Durack DT et al., (9), diagnosed IE by amalgamating the findings of echocardiography with microbiological and clinical data. The three major echocardiographic criteria for diagnosing IE include: 1) the presence of echogenic, opaque, mobile masses denoted as vegetations on the native or prosthetic valve or myocardium, 2) valvular or myocardial abscesses, 3) any breakdown of sutures leading to detachment of the prosthetic valve (10). The definitive diagnosis of IE can be made by the presence of either two major criteria with one minor criterion or the presence of one major criterion with three minor criteria.
The index patient met three of Duke’s major criteria which include the echocardiographic evidence of valvular vegetations, repeated positive blood cultures and new valvular regurgitations, and one minor criterion of high-grade fever above 38ºC (11). Out of 23 known cases of Achromobacter xylosoxidans endocarditis, only eight cases of prosthetic valve endocarditis are known in literature as described in (Table/Fig 3). The presence of an abnormal heart valve was observed in 65% of cases, which acts as a predisposing condition for IE (12),(13),(14),(15),(16),(17),(18),(19).
The age of the patient in present study was 47 years while the mean age of the patients who developed Achromobacter xylosoxidans prosthetic valve endocarditis was around 57.12 years, with equal prevalence among both the genders (12),(13),(14),(15),(16),(17),(18),(19). The vegetations of Achromobacter xylosidans endocarditis were commonly isolated from the prosthetic aortic valve in the studies by Tokuyasu H et al., (12), Ahmad MS et al., (14), Sawant AC et al (16), Van Hal S et al., (17), Lofgren RP et al., (13), and Olson DA and Hoeprich PD (18). Thus, prosthetic aortic valve endocarditis was observed in 66.67% (6/9) cases, which includes present case of prosthetic aortic valve endocarditis (12),(13),(14),(15),(16),(17),(18),(19).
In most of the cases discussed in the literature, IE caused by Achromobacter species was susceptible to beta-lactam antibiotics and beta-lactamase inhibitors, carbapenems, and trimethoprim/ sulphamethoxazole (TMP/SMX) (20), which was in agreement with present study were the patient was started on piperacillin-tazobactam, to which the isolate was sensitive by antibiotic susceptibility testing.
The mortality was more among the patients of Achromobacter species endocarditis who were treated with antibiotics only, in comparison to those managed with valve replacement surgery and antibiotics (12). The mortality among cases with prosthetic valve endocarditis who underwent antibiotic treatment only without valve replacement surgery was about 55.55% (5/9), including index patient in this case (12),(13),(14),(15),(16),(17),(18),(19). Thus valve replacement surgery although deemed important, index patient in this case was unable to survive due to underlying co-morbidities like new regurgitation on all valves and chronic kidney disease needing haemodialysis.
The management and diagnosis of Achromobacter species endocarditis are difficult due to the rare nature and atypical presentation of the disease with immunocompromised conditions and co-morbidities that render the patient susceptible to infections by rarely pathogenic microorganisms. Valve replacement surgery and appropriate antibiotic therapy are the mainstays of treating these cases as complete knowledge of management needs the reference of more rare cases and their treatment strategies to form an effective protocol of treatment.
Authors are indebted for the images of 2-D echocardiography provided to us by Dr. Roopali Khanna, Associate Professor, Department of Cardiology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India.
DOI: 10.7860/JCDR/2022/58337.16952
Date of Submission: Jun 16, 2022
Date of Peer Review: Jul 11, 2022
Date of Acceptance: Aug 18, 2022
Date of Publishing: Sep 01, 2022
AUTHOR DECLARATION:
• Financial or Other Competing Interests: None
• Was informed consent obtained from the subjects involved in the study? Yes
• For any images presented appropriate consent has been obtained from the subjects. No
PLAGIARISM CHECKING METHODS:
• Plagiarism X-checker: Jun 20, 2022
• Manual Googling: Aug 08, 2022
• iThenticate Software: Aug 26, 2022 (5%)
ETYMOLOGY: Author Origin
- Emerging Sources Citation Index (Web of Science, thomsonreuters)
- Index Copernicus ICV 2017: 134.54
- Academic Search Complete Database
- Directory of Open Access Journals (DOAJ)
- Embase
- EBSCOhost
- Google Scholar
- HINARI Access to Research in Health Programme
- Indian Science Abstracts (ISA)
- Journal seek Database
- Popline (reproductive health literature)
- www.omnimedicalsearch.com