Translocated intestinal bacteria cause spontaneous bacterial peritonitis in cirrhotic rats: molecular epidemiologic evidence.
OBJECTIVE
Intestinal bacterial translocation is common in cirrhotic rats with spontaneous bacterial peritonitis, and it is thought to play a major pathogenic role. There has so far been no evidence for clonality between bacteria isolated from intestine and ascites. This study aimed to use molecular epidemiology techniques to show that spontaneous bacterial peritonitis is due to translocated intestinal bacteria.


METHODS
Samples of ascitic fluid, portal blood, mesenteric lymph nodes and ileal contents from healthy (n=10) and ascitic cirrhotic rats with (n=12) or without (n=15) spontaneous bacterial peritonitis were cultured. In six infected rats, DNA macrorestriction fragments of 30 bacterial isolates [Escherichia coli (n=13), Enterococcus faecalis (n=12) and Proteus mirabilis (n=5)] from ascites (n=8), mesenteric lymph nodes (n=7), portal blood (n=6), and ileal flora (n=9) were compared.


RESULTS
Bacterial translocation was more frequent in animals with (58%) than in those without spontaneous bacterial peritonitis (20%, p=0.049) or controls (10%, p=0.026). The same bacterial strain was simultaneously isolated in ascites and in mesenteric lymph nodes and/or ileum in 7/8 (87%) instances. The identity rate for bacteria present in both ascites and mesenteric lymph nodes was 80% (4/5). Likewise, identity was demonstrated in 3/4 instances of bacteria found in both ascites and portal blood.


CONCLUSIONS
These results indicate that spontaneous bacterial peritonitis in cirrhotic rats is mainly due to intestinal bacteria translocated to mesenteric lymph nodes. Portal blood could be a less frequent route.
Llovet
J M
JM
Department of Gastroenterology, Hospital Universitari Germans Trias i Pujol, Badalona, Catalonia, Spain.
Bartolí
R
R
March
F
F
Planas
R
R
Viñado
B
B
Cabré
E
E
Arnal
J
J
Coll
P
P
Ausina
V
V
Gassull
M A
MA
D000818:Animals; D001201:Ascites / Q000150:complications; D002252:Carbon Tetrachloride Poisoning / Q000150:complications; D004247:DNA / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field; D007422:Intestines / Q000382:microbiology*; D008106:Liver Cirrhosis, Experimental / Q000139:chemically induced / Q000382:microbiology*; D008198:Lymph Nodes / Q000382:microbiology*; D008297:Male; D008643:Mesentery; D010538:Peritonitis / Q000382:microbiology*; D051381:Rats; D017207:Rats, Sprague-Dawley
D004247:DNA