Recovery ofBilophila wadsworthiafrom Clinical Specimens in Italy

Abstract

This report is the first survey in Italy to evaluate the incidence of recovery ofBilophila wadsworthiain clinical situations. The survey was carried out at the departments of Microbiology in two Northern Italian hospitals over a one-year period. Tests forB. wadsworthiawere carried out on a range of specimens from different body sites, when etiology by anaerobes was suspected. Out of a total of 350 samples examined, 67% were positive in bacteriological tests. Mixed anaerobic infections were detected in 53 specimens, corresponding to 23% of all cases. Strains ofB. wadsworthiawere isolated from 12 samples, equivalent to 5% and 22% of total and mixed/anaerobic infections, respectively.Bilophila wadsworthiawas always isolated in mixed infections, mainly from the large intestine (67% of cases). The infectious process ofB. wadsworthiawas often complicated by abscess formation, regardless of body site. Interestingly, a strain was isolated from one case of bacteremia. The microorganisms most frequently isolated withB. wadsworthiawereEscherichia colifor facultative species (38%), andBacteroides fragilis, from anaerobic isolates (25%). Production of β-lactamases byB. wadsworthiaisolates was found in ten strains (83%), which appeared to be penicillin G resistant at concentration equal to or greater than the break-point (4 μg/mL). Epidemiological and clinical data from this and previous studies point to the involvement ofB. wadsworthiain mixed infections. To assess the specific contribution of the species to the disease, studies of pathogenetic factors are to be considered in parallel. Nonetheless, production of β-lactamases by mostB. wadsworthiaisolates could easily interfere with the therapeutical approach to infections involving the new species. The addition of a selective medium to culture specimens from the abdominal cavity should be considered in order to detect the presence ofB. wadsworthia.