Evaluation of different methods for diagnosis of hepatitis C virus infection among haemodialysis patients

Haemodialysis [HD] patients are at high risk of hepatitis C virus infection. A comparative study was conducted to evaluate different methods for diagnosis of HCV infection. The study comprised 100 haemodialysis patients and 50 apparently healthy controls. All subjects were investigated for serum albumin, bilirubin, alanine aminotransferase [ALT] and aspartate aminotransferase [AST]. Serum HCV antibodies were detected by 2nd generation enzyme linked immunosorbent assay [ELISA II] and confirmed by recombinant immunoblot assay [RIBA II]. Serum HCV RNA was detected by reverse transcriptase [RT] polymerase chain reaction [nested PCR technique]. Out of 100 HD patients, 77 [77%] were found to be ELISA II positive and 38 [38%] were positive by RT-PCR. Out of 77 positive ELISA II, 68 were positive also by RIBA II and 8 were intermediate. The prevalence of HCV RNA positivity in ELISA II positive and in ELISA II negative groups were 31/77 [40.3%] and 7/23 [30.4%] respectively with no significant correlation. While in the control group, this correlation was highly significant [p=0.0004]. In normal population group [50] 13, 11,4 subjects were HCV positive by ELISA II, RIBA II and PCR respectively. A highly significant correlation [p=0.0008] was found between positive RIBA II and presence of HCV RNA by RT-PCR. In the HD group, compared to PCR results, the sensitivity of RIBA II was 68.4% and specificity was 32.3% versus 100% and 84.8% in the normal group. A highly significant correlation was found between ALT and AST levels in HCV RNA positive versus HCV RNA negative individuals in both groups. This finding was not verified with ELISA II or RIBA II in either groups. In conclusion, combined application of anti-HCV screening assay followed by a confirmatory RIBA assay and HCV RNA detection must be applied to establish HCV infection especially in immunocompromised patients undergoing dialysis. Serial ALT and AST testing must monitor those patients

In vitro susceptibility testing of some candida isolates to ketoconazole and itraconazole using agar dilution and microtiter broth dilution techniques

There is no ideal laboratory procedure or culture medium in current use for susceptibility testing of pathogenic yeasts. In this study 32 isolates of candida species were tested for their in vitro susceptibility to two antifungal drugs [ketoconazole and itraconazole]. Minimum inhibitory concentrations [MIC] of the two drugs were determined. Three species were tested, Candida [C.] albicans [16 isolates], Torulopsis [Candida] glabrate [9 isolates] and Candida krusei [7 isolate]. Two methods were used, agar dilution and microtiter broth dilution techniques. Kimmig medium was used [pH 6. 8]. Incubation was done at 35 degree for 24 h. Final concentrations for both drugs were 0. 1-64 microgram/ml. Based on safely achievable levels in serum, results showed that Candida albicans isolates were more susceptible to itraconazole than ketoconazole [14 of 16 had MIC < 4 microgramml and 9 of 16 had MICs < 4 microgramml respectively]. The most susceptible species to ketoconazole was C. glabrata [7 out of 9 had MICs < 4 microgram/ml. On the other hand C. [Torulopsis] glabrata was less susceptible to itraconazole, one isolate had MIC 64 ugmicrogram/ml in microtiter broth dilution technique. C. Krusei was fairly susceptible to both drugs. Almost no variability was seen between agar dilution and microtiter broth dilution methods. With ketoconazole 22 out of 32 isolates had MIC < 8 microgram/ml with either method. As regard itraconazole 25 and 24 out of 32 isolates were susceptible to < 8 microgram/ml using agar dilution and microtiter broth dilution respectively. We concluded that a microtiter broth system is a simple, precise and economical technique for susceptibility testing of Candida species