Direct Inoculation in BACTEC Culture Media is Superior to Thioglycollate Broth and Solid Culture Medium Method after Centrifugation in Identifying Gram Positive Microorganism in Peritoneal Dialysis Peritonitis Patients / 대한신장학회지

ABSTRACT

PURPOSE: Peritonitis remains one of most important complications of long-term peritoneal dialysis. This study was prospectively performed to compare the ability of identifying the causative organism for continuous ambulatory peritoneal dialysis (CAPD) peritonitis between bedside inoculation into BACTEC culture bottles and method involving centrifugation of effluent followed by plating into solid and liquid media. METHODS: We studied 38 patients with CAPD peritonitis (MF=2117, age 53+/-13 years) between July, 2005 and May, 2006. They had 50 episodes of CAPD peritonitis during the study period. From each peritonitis patient, two aliquots of peritoneal effluent were obtained at the same time. One aliquot was inoculated into two BACTEC culture bottles (aerobic and anaerobic, each 10 mL). The other aliquot was inoculated into thioglycollate broth (TGB, 10mL) and also spread on solid culture media (SCM) after centrifuge 50 mL of effluents. We compared positive-culture results, time from inoculation to identification of growth, and causative organism between these two culture methods. RESULTS: The BACTEC culture method was superior to the TGB & SCM culture method in identifying microorganisms (80% vs. 56%, respectively, p=0.01). Especially, there was significant difference in identifying the gram-positive bacteria between the BACTEC culture method and the TGB & SCM culture method [52% (26/50) vs 36% (18/50), p=0.001]. CONCLUSION: This study indicated that direct inoculation in BACTEC culture media is superior, especially for the gram-positive bacteria, to TGB & SCM in identifying the causative organisms in CAPD peritonitis patients.