Fatal lactic acidosis and acute renal failure after addition of tenofovir to an antiretroviral regimen containing didanosine.

We describe a 49-year-old man with human immunodeficiency virus infection and stable chronic renal insufficiency who developed acute oliguric renal failure and severe lactic acidosis and who died several weeks after tenofovir was added to an antiretroviral regimen that included didanosine. Although the role of tenofovir in precipitating acute renal failure is unclear, progressive accumulation of the drug and pharmacologic interaction that caused increased levels of didanosine were the likely antecedents of increased mitochondrial toxicity that led to lactic acidosis.

HIV protease mutations associated with amprenavir resistance during salvage therapy: importance of I54M.

OBJECTIVE: To examine the clinical significance of HIV protease mutations detected before and after therapy with amprenavir. STUDY DESIGN: Serial plasma HIV loads and protease gene mutations were monitored in 31 patients who received amprenavir, including 19 who had been exposed to other protease inhibitors (salvage therapy). Recombinant phenotyping was used to assess the significance of new mutations appearing after amprenavir therapy. RESULTS: After 6-8 months of amprenavir, 4 treatment-naïve and 5 salvage patients had an undetectable plasma HIV load, while 12 other salvage patients showed less than 10-fold HIV load reduction. HIV protease mutations associated with amprenavir resistance included I84V, I50V, I47V, V32I, and I54M. Among mutations newly detected after amprenavir treatment, I54M occurred in six cases, I54L in two cases, M46I in two cases, I47V in one case and I50V in one case. When compared with pretreatment plasma without the mutation, recombinant phenotyping showed that I54M increased the amprenavir resistance by at least 6-fold, resulting in up to 48-fold resistance over a drug-sensitive control. CONCLUSIONS: Protease I54M frequently appears after amprenavir therapy, and when combined with pre-existing mutations, leads to high-level amprenavir resistance and treatment failure.

Capnocytophaga ochracea causing severe sepsis and purpura fulminans in an immunocompetent patient.

Capnocytophaga ochracea (C. ochracea), a known human microflora, has been reported to cause sepsis in immunocompromised patients and less severe infections such as intrauterine infections, endocarditis, peritonitis and septic arthritis in the immunocompetent patient. We present the first described case of C. ochracea causing severe sepsis and purpura fulminans in an immunocompetent host.

Analysis of sequence configurations of the ISDR, PKR-binding domain, and V3 region as predictors of response to induction interferon-alpha and ribavirin therapy in chronic hepatitis C infection.

Interferon (IFN) and ribavirin combination therapy for chronic hepatitis C virus (HCV) infection yields a sustained response rate of only approximately 40%. Previous studies have linked IFN responsiveness to viral sequence variation in parts of the E2 and NS5A genes, but this remains controversial. We studied pretreatment sera from 28 subjects (23 with HCV genotype 1a) who received high-dose IFN induction followed by IFN-ribavirin combination therapy. Serum HCV sequences were amplified and compared from 14 responders with undetectable HCV RNA 24 weeks after therapy and 11 nonresponders (excluding three who dropped out of the study). Analysis included the E2 PKR eIF-2alpha phosphorylation homology domain (PePHD, codons 659-670), where the sequence was well conserved, and codons 2001-2420 of NS5A. In NS5A, the proposed PKR binding domain (codons 2209-2274), containing the putative IFN sensitivity determining region (ISDR, codons 2209-2248), showed too little variation among subjects to differentiate responders and nonresponders. NS5A codons 2356-2385 (which includes the V3 region) exhibited more variation. Here, six of 12 genotype 1a responders showed four or more amino acid changes from the prototype HCV-1 sequence, as compared with one of eight nonresponders, but this fell short of statistical significance (P = 0.16). NS5A sequences from posttreatment sera were examined in six nonresponders to look for selection of treatment-resistant viral subpopulations, but no consistent change was detected. In conclusion, our results indicate that the sequences of the ISDR, the PKR-binding domain, and the PePHD are unlikely to have predictive value for IFN treatment success in those infected with HCV genotype 1a. However, the finding of greater variability among treatment responders in the carboxy end of NS5A suggests that the V3 region merits further investigation.