agar and Peritonitis

Continuous ambulatory peritoneal dialysis (CAPD)-associated peritonitis remains a major complication in patients on CAPD leading to increased morbidity and mortality. Successful therapy of peritonitis is highly dependent on a positive microbiological culture because narrow spectrum antibiotics are essential to efficiently combat infection. Therefore, this study evaluated the performance of Tween 80 containing media at three different concentrations (0.1%, 1.0% and 2.0%) to increase the pathogen yield from peritoneal fluid in comparison with the standard culture media.. Peritoneal fluid samples (n=121) obtained from CAPD patients suspected of peritonitis at Hospital Kuala Lumpur were analysed macroscopically and microscopically prior to culture. All samples were cultured on seven different culture media, including sheep blood agar, MacConkey agar, Sabouraud dextrose agar, brain heart infusion agar and Tween 80 incorporated blood agar. All plates were incubated at an optimum temperature up to 48 hours.. Among all the culture media investigated, 0.1% to 2.0% Tween 80 incorporated blood agar yielded the highest positive culture (23/121) in comparison with all other standard media, thus lowering the negative culture rate among CAPD patients. Statistical analysis by Chi Square revealed significant differences (p <0.001) between the three concentrations of Tween 80 tested in this study. Among the three different concentrations of Tween 80 optimised in this study, blood agar containing 0.1% Tween 80 generated the best results, achieved by optimum growth of all Gram-positive organisms, Gram-negative organisms and yeast cells simultaneously. Using a small amount of detergent at low cost significantly increased the pathogen yield during CAPD-associated peritonitis.

Topics: Agar; Ascitic Fluid; Culture Media; Hospitals; Humans; Peritoneal Dialysis, Continuous Ambulatory; Peritonitis; Polysorbates

Treatment of peritonitis requires prompt surgery and antibiotic therapy. It usually takes two or three days to obtain definitive results of peritoneal cultures and to adapt empirical antibiotic therapy. We assessed the potential time gain associated with direct culture of peritoneal samples on antibiotic agar (AA).. Peritoneal samples from 31 consecutive patients undergoing surgery for suspected community-acquired peritonitis were cultured according to the standard method and on AA containing one of the following five regimens: amoxicillin/clavulanic acid + gentamicin, ticarcillin/clavulanic acid + gentamicin, cefotaxime +metronidazole, piperacillin/tazobactam, or ertapenem. We compared the treatment modifications made by physicians aware only of the results of the standard method with the modifications the AA method would have indicated.. Fewer isolates were identified by direct culture on AA than by the standard method (17 vs. 45; p = 0.0001), but definitive results were obtained much more rapidly (median 1 [range 1-3] days vs. 3 [range 2-7] days; p < 0.0001). Antibiotic regimens were changed for 14 patients on the basis of the results of the standard method (broader antibiotic spectrum and narrower spectrum in seven patients each). With the AA method, these changes could have been indicated after a median of 1 (range 1-2) days instead of 4 (range 1-11) days (p = 0.0006). The AA method missed only one resistant bacterial strain and isolated nine strains not detected by the standard method, including an extended-spectrum beta-lactamase-producing Escherichia coli. A complicated outcome was more frequent in patients having isolates found with the AA but not the standard method (86% vs. 21%; p = 0.003).. Use of the AA method for culture of peritoneal samples from patients with community-acquired peritonitis speeds appropriate adaptation of antibiotic therapy and warrants further investigation.

Topics: Adult; Agar; Aged; Aged, 80 and over; Anti-Bacterial Agents; Bacteria; Community-Acquired Infections; Culture Media; Female; Humans; Male; Microbial Sensitivity Tests; Middle Aged; Peritonitis; Pilot Projects; Time Factors; Young Adult

Spontaneous bacterial peritonitis is a life-threatening complication of cirrhotic ascites. Optimal patient management depends on the isolation of the causal organism from ascitic fluid. To evaluate culture techniques for the diagnosis of spontaneous bacterial peritonitis, we prospectively compared three blood culture system, the Isolator system, a lysis-centrifugation system, the Septi-Chek system, a biphasic culture system, and a nonvented tryptic soy broth system, all inoculated at the bedside, and our standard method of direct inoculation of specimens after transport to the laboratory onto agar plates and into thioglycolate broth. The results showed that the Septi-Chek and nonvented tryptic soy broth systems each recovered statistically significantly more pathogens than either the Isolator system (P = 0.0084) or the standard method (P = 0.00098). The Isolator system recovered more pathogens than the standard plate method, but this difference was not statistically significant. Both the Isolator system and the standard plate method recovered more contaminating microorganisms than the Septi-Chek or nonvented tryptic soy broth system. The Isolator system required the most processing time compared with the processing times required by any other method.

Topics: Adult; Agar; Aged; Aged, 80 and over; Bacterial Infections; Bacteriological Techniques; Culture Media; Evaluation Studies as Topic; Female; Humans; Liver Cirrhosis; Male; Middle Aged; Peritonitis; Prospective Studies; Time Factors

Topics: Agar; Animals; Germ-Free Life; Giant Cells; Guinea Pigs; Macrophages; Peritonitis; Research