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Expression of sulfamethoxazole biotransformation pathways in a macaque model of HIV infection

ABSTRACT: Potentiated sulfonamide antibiotics such as trimethoprim/sulfamethoxazole (cotrimoxazole or TMP/SMX) remain the drugs of choice for treatment and prevention of Pneumocystis jiroveci pneumonia, toxoplasma encephalitis, and Isospora infections in HIV infection (aidsinfo.nih.gov). However, HIV-infected patients show a markedly increased risk of delayed hypersensitivity (HS) reactions to TMP/SMX (20-57% incidence) when compared to the general population (3% incidence). The typical manifestation is maculopapular rash with or without fever, and TMP/SMX is the most common cause of cutaneous drug reactions in HIV-infected patients TMP/SMX can also lead to thrombocytopenia, hepatotoxicity, and bullous skin eruptions in more severely affected patients. The risk of sulfonamide HS increases with progression to AIDS, with higher risk seen at lower CD4+ counts. This risk has been attributed, at least in part, to acquired alterations in SMX drug disposition in HIV infection. We hypothesized that HIV infection leads to impaired hepatic SMX detoxification or enhanced SMX bioactivation pathways, which may contribute to the increased incidence of sulfonamide HS. We addressed this question using liver tissue from SIVmac239-infected macaques, a well accepted model of HIV infection. The aim of this study was to evaluate differences in the hepatic expression and activity of SMX biotransformation pathways from drug naïve SIV-infected macaques compared to sex- and age-matched uninfected controls.

ORGANISM(S): Macaca mulatta

PROVIDER: GSE87158 | GEO | 2017/07/11

SECONDARY ACCESSION(S): PRJNA343740

REPOSITORIES: GEO

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Project description:Staphylococcus aureus thymidine-dependent small-colony variants (TD-SCVs) are frequently isolated from patients with chronic S. aureus infections after long-term treatment with trimethoprim-sulfamethoxazole (TMP-SMX). In TD-SCVs, mutations of thymidylate synthase (thyA, TS), essential for DNA synthesis, occur. However, it has never been shown, that TMP-SMX is responsible for the induction and selection of TD-SCVs. Short-term exposure of TMP-SMX induced the TD-SCV phenotype morphologically as shown in transmission electron-microscopy and on the transcriptional level by qRT-PCR in wild-type S. aureus, while selection of TD-SCVs with thyA mutations occurred only rarely after long-term exposure. In reversion experiments with clinical TD-SCVs, all revertants revealed compensating mutations at the initially identified mutation site. Whole DNA microarray analysis of a thyA deletion mutant (∆thyA), which exhibited the typical TD-SCV phenotype, identified tremendous alterations compared to the wild-type. Important virulence regulators such as agr, arlRS, sarA and major virulence determinants including hla, hlb, sspA, sspB and geh were down-regulated, while genes associated with the colonization capacity like fnbA, fnbB, spa, clfB, sdrC and sdrD were up-regulated. The expression of genes involved in pyrimidine and purine metabolism as well as in nucleotide interconversion changed significantly. The ∆thyA-mutant was attenuated in virulence in both, a Caenorhabditis elegans killing model and an acute murine pneumonia model. Furthermore, competition experiments in vitro and in vivo (using a chronic pneumonia mouse model) revealed a survival and growth advantage of the ∆thyA-mutant under low thymidine conditions and TMP-SMX exposure. In conclusion, our results clearly show for the first time that TMP-SMX induces the TD-SCV phenotype after short-term exposure in S. aureus and that long-term exposure selects thyA mutations providing an advantage for TD-SCVs under specified conditions. Thus, our results help to understand the dynamic processes of induction and selection of S. aureus TD-SCVs during TMP-SMX exposure.

Project description:Staphylococcus aureus thymidine-dependent small-colony variants (TD-SCVs) are frequently isolated from patients with chronic S. aureus infections after long-term treatment with trimethoprim-sulfamethoxazole (TMP-SMX). In TD-SCVs, mutations of thymidylate synthase (thyA, TS), essential for DNA synthesis, occur. However, it has never been shown, that TMP-SMX is responsible for the induction and selection of TD-SCVs. Short-term exposure of TMP-SMX induced the TD-SCV phenotype morphologically as shown in transmission electron-microscopy and on the transcriptional level by qRT-PCR in wild-type S. aureus, while selection of TD-SCVs with thyA mutations occurred only rarely after long-term exposure. In reversion experiments with clinical TD-SCVs, all revertants revealed compensating mutations at the initially identified mutation site. Whole DNA microarray analysis of a thyA deletion mutant (M-bM-^HM-^FthyA), which exhibited the typical TD-SCV phenotype, identified tremendous alterations compared to the wild-type. Important virulence regulators such as agr, arlRS, sarA and major virulence determinants including hla, hlb, sspA, sspB and geh were down-regulated, while genes associated with the colonization capacity like fnbA, fnbB, spa, clfB, sdrC and sdrD were up-regulated. The expression of genes involved in pyrimidine and purine metabolism as well as in nucleotide interconversion changed significantly. The M-bM-^HM-^FthyA-mutant was attenuated in virulence in both, a Caenorhabditis elegans killing model and an acute murine pneumonia model. Furthermore, competition experiments in vitro and in vivo (using a chronic pneumonia mouse model) revealed a survival and growth advantage of the M-bM-^HM-^FthyA-mutant under low thymidine conditions and TMP-SMX exposure. In conclusion, our results clearly show for the first time that TMP-SMX induces the TD-SCV phenotype after short-term exposure in S. aureus and that long-term exposure selects thyA mutations providing an advantage for TD-SCVs under specified conditions. Thus, our results help to understand the dynamic processes of induction and selection of S. aureus TD-SCVs during TMP-SMX exposure. 18 independent samples were analysed; for each isolate and time point 3 replicates were performed

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Expression of sulfamethoxazole biotransformation pathways in a macaque model of HIV infection

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