Stenotrophomonas (Xanthomonas) maltophilia as an emerging opportunistic pathogen in association with HIV infection: a 10-year surveillance study.
BACKGROUND
Stenotrophomonas (Xanthomonas) maltophilia has been increasingly reported as a nosocomial opportunistic pathogen, responsible for serious infectious complications in immunocompromised patients. At present very limited information is available concerning its clinical significance in the setting of HIV infection.


METHODS
A retrospective survey of clinical and microbiological records of 1,374 HIV-infected patients referring to our tertiary care center during a 10-year period (1991-2000) was performed to identify all episodes of S. maltophilia infection and analyze epidemiological, clinical and laboratory variables. The episodes of S. maltophilia bacteremia were compared with those caused by non-typhoid Salmonella spp. occurring in HIV-infected patients referring to our center during the same period, in order to evaluate eventual predisposing risk factors.


RESULTS
61 episodes of S. maltophilia infection were observed in 59 HIV-infected patients: sepsis/bacteremia in 48 cases (78.7%), lower airways infection in five, urinary tract infection in four, pharyngitis in two, lymphadenitis and liver abscess in one case each. 47 of 61 episodes (77%) of S. maltophilia infection occurred as nosocomial disease (i.e. were diagnosed after the 3rd day of hospitalization) and bacterial isolates showed an elevated resistance profile against many beta-lactam compounds, aztreonam, imipenem and aminoglycosides. At the same time, 38 episodes of bacteremia due to non-typhoid Salmonella spp. were diagnosed in our patients, 13 of which were nosocomial infections.


CONCLUSIONS
When compared with non-typhoid Salmonella spp. bacteremia, a significantly higher risk of developing S. maltophilia disseminated infection was seen in association with advanced immunodeficiency, leukopenia-neutropenia, central venous catheterization, prior broad-spectrum antimicrobial therapy and/or corticosteroid treatment.
Calza
L
L
Department of Clinical and Experimental Medicine, Section of Infectious Diseases, University of Bologna, S. Orsola Hospital, via G. Massarenti 11, I-40138 Bologna, Italy. malinf@med.unibo.it
Manfredi
R
R
Chiodo
F
F
D017088:AIDS-Related Opportunistic Infections / Q000175:diagnosis / Q000453:epidemiology*; D000328:Adult; D017677:Age Distribution; D016470:Bacteremia / Q000175:diagnosis / Q000453:epidemiology*; D005260:Female; D016905:Gram-Negative Bacterial Infections / Q000175:diagnosis / Q000453:epidemiology*; D006306:Health Surveys; D006801:Humans; D015994:Incidence; D007558:Italy / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D011336:Probability; D011379:Prognosis; D012189:Retrospective Studies; D018570:Risk Assessment; D017678:Sex Distribution; D020615:Stenotrophomonas maltophilia / Q000302:isolation & purification*