A case report of vascular catheter-associated bacteremia caused by Mycobacterium tuberculosis in a non-immunosuppressed patient

Abstract

SUMMARYMycobacterium tuberculosis was isolated from a central venous catheter in a non-immunosuppressed patient with systemic tuberculosis.This case report represents a very uncommon form of isolation of Mycobacterium tuberculosis. A total improvement was obtained after treatment. KEYWORDS:Mycobacterium tuberculosis ; Bacteremia; Sepsis; Blood. CASE REPORTA 45 year-old man, with fever, cough and weight loss (4 kg/30 days) was admitted to the hospital. The chest X-ray shows left pleural effusion, and infiltration on both lungs. The patient underwent a central venous catheterization and after the catheter removal Mycobacterium tuberculosis was identified from it at the microbiology laboratory. The anti-HIV test was negative.The patient received antimycobacterial therapy for six months with total improvement. Microbiological investigationThe material obtained from the luminal side of the catheter was Gram-stained and a neutral gram bacilli were observed, suggesting mycobacteria. In the presence of acid fast bacilli by the Ziehl-Neelsen, the material was planted in Lowenstein-Jensen and 30 days after, a Mycobacterium spp was isolated. The germ was sent to the Reference Mycobacteriology Laboratory and was identified as Mycobacterium tuberculosis. Growth more than 7 days, non pigmented colonies, niacin positive, in Ogawa with drugs (PNB negative and TCH positive). DICUSSIONDespite their medical therapeutic qualities, catheters serve as a major focal point for infections, either as consequence of colonization of the canula wound or of the surface and/or luminal side of the catheter itself. In most instances the offending microorganisms have been species of Staphylococcus, Streptococcus, gram-negative bacilli, Corynebacterium, and Candida 5,7 .The recognition of nontuberculous mycobacteria, especially Mycobacterium chelonae, as cause of infection in the setting of long-term indwelling intravascular catheters has only recently gained the appreciation of clinicians and microbiologists 1,2,4 .In the present report, we describe a patient with pleural and pulmonary tuberculosis who developed a central venous catheter-associated bacteremia caused by M. tuberculosis.The M. chelonae is now being increasingly recognized as the cause of catheter-related infections, specially in patients with cancer 1,4 . They can cause exit site infections, tunnel infections or catheter associated bacteremia with disseminated disease. These rapidly growing mycobacteria are ubiquitous in nature, found in soil, water and dust. They also have been isolated from the respiratory and gastrointestinal tracts of humans without evidence of disease. On the Gram-stained smear they appear to be Gram-positive bacilli and are often mistaken by Corynebacterium species 6 .The report of a M. tuberculosis catheter associated infection seems to be very unusual, and it was possible to detect this germ, in this report, because of the meticulous routine done during the processment of the specimen. It was crucial to detect the organisms. The microscopy was very helpful...