Increasing frequency of Gram-positive bacteria in spontaneous bacterial peritonitis

To evaluate the characteristics and possible recent changes of the microbial causes of spontaneous bacterial peritonitis (SBP) in cirrhotic patients.

We retrospectively evaluated 42 cirrhotic patients with positive ascitic fluid culture and without evidence of secondary peritonitis who were admitted consecutively to our Department between 1998 and 2002.

Twenty (48%) of 42 patients with positive ascitic fluid culture were diagnosed during 1998-1999 (period A) and the remaining 22 (52%) patients during 2000-2002 (period B). Gram-negative bacteria were the cause of SBP in 15 (75%) of the 20 patients during period A and in only nine (41%) of the 22 patients during period B (P=0.026). SBP patients with Gram-positive bacteria compared with those with Gram-negative bacteria were less frequently in Child class C (P=0.058) and had significantly higher ascitic fluid protein (P=0.014) and albumin concentrations (P=0.009) and lower ascitic fluid neutrophil count (P=0.008). Resistance to quinolones was detected significantly more frequently in the isolated Gram-positive than Gram-negative bacteria (P<0.001).

Culture-positive SBP in cirrhotic patients are caused more frequently by Gram-positive bacteria during the recent years, which are, in their vast majority, resistant to quinolones.