The bacteria typically described from biliary tract infection include Escherichia coli, Klebsiella, Enterobacter, and enterococci. It has also been recognized for some time that Clostridium perfringens may occasionally be involved in serious complications of biliary tract infection such as sepsis and emphysematous cholecystitis. Other anaerobes, including various Bacteroides and Fusobacterium sp, clostridia other than C perfringens, anaerobic cocci and streptococci, and Actinomyces have been reported from a variety of biliary tract infections, usually as single case reports.1 More recently, several reports indicate that anaerobes, and especially B fragilis, may be more common in biliary tract infections than had been appreciated.1-4 Anaerobes have been recovered in approximately 40% of such infections; B fragilis is the most common anaerobe encountered. Anaerobes may also be found, as aerobes are, in asymptomatic bactibilia.
The interesting report of Bourgault et al in this issue (see p 1346) compares clinical features of biliary tract infection