The intestinal flora and bacterial infection in cirrhosis.

Bacterial infection, especially with intestinal-type bacterial flora, is a common complication in patients with cirrhosis [1–4]. Spontaneous bacterial peritonitis (SBP), urinary tract infection, pneumonia, spontaneous bacterial empyema and bacteraemia are the most frequent infective complications in this group. The incidence of infection with Gram-positive cocci, in particular, has increased in recent years, with such flora now the most frequent isolates in hospitalised cirrhotics with nosocomial infection, especially those admitted to intensive care units, presumably due to the high rate of requirement for invasive procedures in this group [4]. Recent data suggest that between 15% and 35% of cirrhotic patients admitted to hospital develop nosocomial bacterial infection, substantially higher than the infection rate in the order of 5% to 7% in the general hospital patient setting [5]. Excluding sepsis related to invasive procedures in hospitalised patients, several factors likely predispose to the increased potential for bacterial infection in patients with cirrhosis. Increasing evidence points to a key role for bacterial translocation of intestinal flora from the intestinal lumen, in combination with failure of anti-bacterial defence mechanisms to efficiently clear these translocating microorganisms [6]. The latter defences include reduced opsonic activity due to low hepatic synthesis of complement, deranged function of macrophage Fc gamma receptors and reduced phagocytic and killing capacity of neutrophils [7–10]. The high prevalence of associated malnutrition in cirrhotic patients [11] exacerbates the potential for infection. Impairment of mucosal immunity may also be important [12]. Complicating bacterial infection may have severe adverse clinical consequences in cirrhotic patients.