A decade surveillance study of Mycobacterium xenopi disease and antimicrobial susceptibility levels in a reference teaching hospital of northern Italy: HIV-associated versus non-HIV-associated infection.

OBJECTIVE AND METHOD: The aim of our survey is to investigate the epidemiology and in vitro antimicrobial susceptibility levels of 35 consecutive Mycobacterium xenopi strains responsible for confirmed disease at a University Hospital from 1993 to 2002 and to identify eventual differences in the in vitro sensitivity profile between the 17 strains isolated from patients with HIV disease and the 18 isolates cultured from non-HIV-infected individuals. RESULTS: The involvement of lower airways accounted for 88.6% of cases; but atypical pulmonary findings, including cavitation and a prominent inflammatory reaction, recently emerged in HIV-infected patients successfully treated with HAART, which raises the possible role of immune reconstitution syndrome in the clinical pathomorphism of this opportunistic disease. When compared with non-HIV-infected patients, patients with HIV disease had a lower mean age and a tendency to suffer from late relapses. The greatest overall in vitro sensitivity rate was registered for capreomycin and protionamide (100% of strains) followed by kanamicin (96.6%), whereas susceptibility rates for the first-line compounds such as ethambutol, isoniazid, and rifampicin were slightly lower (85.7% to 91.4%). No temporal variation in the susceptibility index was seen over the study decade. Non-HIV-infected patients experienced a higher frequency of M. xenopi isolates that proved to be resistant to at least one tested compound compared with HIV-associated episodes, despite the heavy and prolonged exposure of HIV-infected patients to broad spectrum antimicrobials, which included agents effective on atypical mycobacteria. Only one HIV-positive patient developed rifampicin resistance in his third disease recurrence. CONCLUSION: A rapid diagnosis, a reliable differentiation between colonization and disease, and an optimal therapeutic choice for atypical mycobacterial disease (including M. xenopi one) are still serious challenges for clinicians and bacteriologists who treat immunocompromised patients, such as those with HIV disease. In the immunocompromised host, diagnostic difficulties posed by late identification and eventually concurrent opportunistic disorders add their negative effects to therapeutic problems due to the unpredictable in vitro susceptibility profile of atypical mycobacteria, such as M. xenopi.

Role of Mycobacterium xenopi disease in patients with HIV infection at the time of highly active antiretroviral therapy (HAART). Comparison with the pre-Haart period.

BACKGROUND AND SETTING: A reliable and timely clinical, radiological, and bacteriological diagnosis, and an optimal treatment of non-tubercular mycobacteriosis (including Mycobacterium xenopi disease), remain an unanswered challenge for clinicians facing immunocompromised patients, including those with HIV infection. OBJECTIVE: The aim of our survey is to report the frequency, and the epidemiological, immunological, microbiological, clinical, and therapeutic features of all confirmed HIV-associated M. xenopi disease observed from 1993-2002, with special attention paid to eventual differences that emerged after the introduction of potent antiretroviral therapy (highly active antiretroviral therapy, HAART), on the basis of an international literature update. DESIGN AND RESULTS: Our series of 17 consecutive confirmed M. xenopi infections retrieved in 14 out of 3000 patients followed for HIV disease complications raises a broad series of clinical, diagnostic, therapeutic, and prophylactic concerns. The great majority of M. xenopi disease involved the lower respiratory tract, but atypical features including cavitation and prominent exudative features became apparent in patients successfully treated with HAART, pointing out the possible role of the so-called immune reconstitution syndrome in these episodes. CONCLUSIONS: Diagnostic problems represented by late or missed identification due to slow culture and frequently concomitant opportunistic disorders, join therapeutic difficulties due to the unpredictable in vitro antimicrobial susceptibility profile of these organisms, selection of treatment and chemoprophylaxis according with clinical-radiological and microbiological suspicion, and concomitantly administered medications.

[Reduction of antibiotic resistance of Enterococcus faecalis in infections of the genitourinary tract]. / Riduzione dell'antibiotico-resistenza di Enterococcus faecalis in isolati urinari.

Antimicrobial susceptibility levels of Enterococcus faecalis isolated from urine were followed up at our University Hospital during three years (1999-2001), in order to evaluate the trend of antibiotic resistance of this common community-acquired pathogen of the genito-urinary tract. One thousand and 249 consecutive strains were examined, and a surprisingly low resistance profile was detected. As a result, penicillin , ampicillin, nitrofurantoin and piperacillin may still represent first-line agents in our area when community-acquired urinary tract enterococcal infections is of concern, pending in vitro susceptibility studies.

Fatal Campylobacter jejuni bacteraemia in patients with AIDS.

Two fatal cases of Campylobacter jejuni septicaemia in patients with AIDS were characterised by severe HIV-related immunodeficiency, negative stool cultures and presentation during hospitalisation, developing a clinical picture of fulminant septic shock despite therapy with appropriate antibiotics. Campylobacter spp. are important opportunist pathogens in HIV disease and may cause a septicaemic illness in the absence of enteric disease.