Antimicrobial treatment of invasive non-perinatal human listeriosis and the impact of the underlying disease on prognosis

Listeriosis is a resurgent foodborne disease in European countries. Benefits of combined β-lactam-aminoglycoside treatment remain controversial and the impact of the underlying disease on prognosis has not been fully assessed. We conducted a retrospective review of cases of sporadic listeriosis in adults from 1995 to 2008 at two university-affiliated hospitals serving a population of 600,000 people in Madrid, Spain. The primary end-point was the associated in-hospital mortality. Sixty-four patients were studied. Estimated incidence of listeriosis was 0.76/100.000 persons/year. Seventy-four per cent had chronic underlying diseases; cirrhosis of the liver and haematological and solid neoplasias were the most common comorbidities. Primary bacteraemia (58%) and meningitis (42%) were the most frequent manifestations. Focal infections were seen in ten cases. In-hospital mortality was 31%. Patients treated with ampicillin or with an ampicillin-gentamicin combination did not differ in age, severity of underlying disease or type of presentation. Differences in mortality were not seen between patients treated with monotherapy and those given combined treatment (28% vs 35%; p 0.634). Ten patients were treated with trimethoprim-sulfamethozaxole alone and only one died. All patients without comorbidities survived infection but mortality of patients with cirrhosis of the liver was 21% and that of patients with haematological or solid neoplasias was 66%. Only haematological neoplasia (OR 6.67; 95% CI 1.71-26.04; p 0.006) was significantly associated with an increased risk of mortality (R(2) (Cox-Snell) = 0.262). Mortality of listeriosis mainly depended on the severity of the underlying disease. Combined ampicillin-gentamicin therapy did not improved survival. Trimethoprim-sulfamethozaxole may be an effective alternative therapy for listerial infections.