Native Valve Endocarditis in a Dialysis Patient by Achromobacter xylosoxidans: Rare Pathogen

Abstract

Background. Achromobacter xylosoxidans (A. xylosoxidans) is a Gram-negative bacillus which causes infections including bacteremia, meningitis, osteomyelitis, prosthetic valve endocarditis, peritonitis and pneumonia. Methods. A 54-year-old male presented with generalized weakness, body ache and fever with chills for about 2 weeks. No history of sore throat, shortness of breath, chest pain, skin lesions or arthralgia. His medical history included dialysis dependent end stage renal disease secondary to hypertensive nephropathy. Physical examination revealed temperature, 102.3°F, pulse rate 115/minute respiratory rate 12/minute, blood pressure 137/80 mmHg. No pallor, lymphadenopathy or jugular venous distension was present. Heart sounds were normal with a grade II/VI intensity pansystolic murmur best heard in mitral area, which conducted to the left axilla and accentuated in left lateral decubitus position. Laboratory tests: hemoglobin 12.6 gm%, white blood cell count 9600/mm3 with neutrophils 70.4%, lymphocytes 12.6%, monocytes 13.7%, eosinophils 2.0% and basophils 1.3%. A set of blood cultures was sent at this time. Results. Two-dimensional echocardiography showed presence of vegetations on aortic and mitral valves with regurgitant lesions. Transesophageal echocardiography confirmed these findings. He was started empirically on parenteral vancomycin, piperacillin-tazobactam and gentamicin. Blood culture isolated A. xylosoxidans which was sensitive to piperacillin-tazobactam and ceftazidime and resistant to ampicillin, gentamicin, imipenem and aztreonam. Repeat blood cultures were drawn every 48 hours which grew the same pathogen, indicating persistent bacteremia. There was no resolution of vegetations on echocardiography. Consequently, cardiovascular surgery was consulted for prosthetic valve replacement. Conclusion. There have been reports of transmission of A. xylosoxidans via contaminated indwelling catheters, tubings and the unhygienic hands of healthcare workers. There is a possibility that in our patient, infection occurred consequent to crosscontamination due to poor hygienic practices. This bacteria is characteristically resistant to multiple commonly used antibiotics and hence its eradication becomes difficult.