Bacterial isolation with on-site inoculation of ascites fluid into hemoculture bottle in spontaneous bacterial peritonitis

Abstract

Objective: To compare the on-site bacterial inoculation of ascites fluid into hemoculture bottle with routine method in the patients who were preliminary diagnosed of SBP Material and Method: A retrospective analysis of case records during January-December 2001. Results: A total of 673 specimens from 325 patients were retrieved from the data records at the Department of Microbiology, Siriraj Hospital in 2001. The neutrocytic ascites were found in 163 specimens (94 patients). The routine method and on-site inoculation into the hemoculture bottle were employed in 107 and 56 specimens respectively. Culture-positive neutrocytic ascites was found in the routine method 16 (14.9%) specimens and in the on-site inoculation 26 (46.4%) specimens (p <0.0001). Among these samples, the two methods were simultaneously performed in 42 specimens of which 18 paired specimens were eligible for analysis. Positive culture was found in 2 samples in which the routine method and in an additional 5 samples in which on-site inoculation into hemoculture bottle method. Using Kappa analysis (ê score = 0.328, 95% CI = -0.172 to 0.829) that can be interpreted the on-site inoculation method had a higher yield than the routine technique. Moreover, 21 cases also had their blood and ascites samples simultaneously collected and cultured 4 of ten (19%) and 5 of eleven (23.8%) cases werefound in the routine and on-site and direct inoculation groups respectively. These finding suggested that the severity of infection in among two groups were similar and unlikely to be the cause of the difference of the positive isolation rate in both groups. Conclusion: The on-site and direct inoculation of ascites into hemoculture bottle method had a significantly higher isolation rate than routine method (i.e. 46.4% versus 14.9% p < 0.0001) either with separated or paired samples of ascites.