The existence of Helicobacter pylori in the biliary tract was investigated. Seven bile samples were included in this study. Among them, six bile samples were collected by percutaneous transhepatic cholangiodrainage and the other by needle aspiration during cholecystectomy. Using nested PCR with two sets of primers homologous to the urease A gene, Helicobacter pylori DNA was detected. Three samples, one from a patient with advanced gastric cancer involving the pancreatic head and two from patients with pancreatic head tumor, were found to be positive for Helicobacter pylori DNA. On the other hand, three samples from patients with cholangiocarcinoma and one from a patient with chronic cholecystitis were all negative. To further verify the specificity of our PCR analysis, partial sequences of the PCR products from the three positive samples were analyzed by direct sequencing. Several silent mutations and a missense mutation (AAA to AGA; Lys-164 to Arg-164) were identified in the urease A gene. We conclude that Helicobacter pylori DNA can be easily detected in the bile samples. The possibility of asymptomatic cholangitis caused by this organism requires further investigation.
The concordance rate between a rapid urease test (CLOtest) and polymerase chain reaction (PCR) assay for the detection of Helicobacter pylori in gastric biopsy samples was investigated. To avoid the bias produced by patchy distribution of the organism in the stomach, the samples used for these two tests were not obtained from two different sites of the antrum. Instead, the PCR assay was performed with the the same biopsy sample that was taken for the CLOtest. Among 82 biopsy samples included for this study, 56 were positive and 26 were negative by CLOtest. Of the 56 CLOtest-positive samples, 52 (93%) were also positive by PCR assay, and of the 26 CLOtest-negative samples, 20 (78%) were negative by PCR assay. The total concordance rate of these two tests was 87.6%. Of the 4 cases with CLOtest-positive and PCR-negative results, 3 had been treated with long-term H2 blockers. Of the 6 patients with CLOtest-negative and PCR-positive results, 4 suffered from recurrent or poorly healing duodenal ulcers. Interestingly, a significantly lower density of the PCR products was observed during electrophoresis analysis for all the 6 cases, presumably due to a small number of H. pylori in these samples. These results indicated that PCR might be used as a complementary assay for CLOtest. False negative results by CLOtest might occur when only a small amount of H. pylori was present in the samples, which could be detected by subsequent PCR assays using the same biopsy specimens. The clinical significance of such CLOtest-negative and PCR-positive cases requires further study.
Background: Antibiotic resistance in Gram-negative baccilli (GNB) is escalating globally; thus achieving optimal antimicrobial exposures has become considerably more challenging. We used data from ''Tracking Resistance in the United States Today (TRUST) surveillance program'' to compare the probabilities of attaining requisite antibiotic exposures against Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa.Methods: Using Monte Carlo simulation, pharmacodynamic profiling was performed for standard and prolonged infusions of cefepime 1&2gq12 h, 2gq8h(0.5h&3 h infusions); ceftazidime 1&2gq8h(0.5&3 h); ceftriaxone; 1&2gq24h(0.5 h); ciprofloxacin 0.4gq8&12h(1 h); doripenem 0.5, 1&2gq8h(1&4 h); ertapenem 1gq24h(0.5 h); imipenem 0.5gq6&8h(0.5 h), 1gq8h(0.5&3 h); levofloxacin 0.75gq24h(1 h); meropenem 0.5gq6&8h(0.5 h) then 1&2gq8h(0.5&3 h); piperacillin/tazobactam 3.375&4.5gq6h(0.5 h), 3.375gq8h(4 h), 4.5gq6h(3 h). MIC data were incorporated from the 2008 TRUST program. Pharmacodynamic targets were defined as fT>MIC >40% for carbapenems, 50% for penicillins and cephalosporins. A total AUC/MIC ≥87 and ≥125 was applied for levofloxacin and ciprofloxacin, respectively. The cumulative fraction of response (CFR) was determined for each regimen against each population of organisms. Optimal CFR was defined a priori as ≥90%.Results: The fluoroquinolones displayed the lowest susceptibilities against all organisms. All cephalosporins, carbapenems and piperacillin/tazobactam had susceptibility rates >90% for Enterobacteriaceae. Against P. aeruginosa, piperacillin/tazobactam portrayed the highest percent susceptibility(90%), followed by meropenem(89.8%), cefepime(88%), and ceftazidime/doripenem(86%). All $lactam regimens achieved optimal CFR against E. coli, and all but piperacillin/tazobactam 3.375 g q6h achieved optimal CFR against K. pneumoniae. The fluoroquinolones achieved the lowest CFRs against all organisms. Against P. aeruginosa, high dose, prolonged infusion doripenem and meropenem achieved CFRs of 97.2% to 98.8%, followed by high dose, prolonged infusion ceftazidime(93.3%) and cefepime(93.2%). No regimens achieved optimal CFR against A. baumannii. Prolonged infusion regimens increased CFR for all $-lactams against the non-fermenting GNB.Conclusion: Standard intravenous doses of many commonly $-lactam regimens have a high probability of achieving optimal exposure against Enterobacteriaceae. For non-fermenting-GNB, higher dose, prolonged infusions of cefepime, ceftazidime, doripenem, and meropenem offered the highest probabilities of achieving bactericidal exposure.
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