First-line anti-tuberculosis drug challenge reactions in DRESS in an HIV endemic setting.

BACKGROUND: In high HIV prevalence settings, first line anti-tuberculosis drug (FLTD)-associated DRESS poses therapeutic challenges. Sequential and additive drug challenge (SADC) of FLTDs best identifies offending drug(s), avoids unnecessary exclusions, and optimises re-initiation of non-offending drugs. However, SADC-associated reaction complexities limit its utility. OBJECTIVE: We aimed to describe characteristics of FLTD-associated DRESS patients, their treatment-limiting SADC reactions and related outcomes. METHODS: Patients hospitalized with FLTD-associated DRESS from 2013-2023 in a South African tertiary hospital and enrolled (retrospectively or prospectively) in an existing registry were eligible. RESULTS: SADC was undertaken in 41 patients. Overall, 47 classifiable reactions occurred, 34/47(72%) in 29/41(71%) patients, were treatment-limiting and 12/41(29%) reinitiated FLTDs uneventfully. Fifteen single and eight multiple drug-reactors were identified. Rifampicin, in 13/23(57%) reactors was the commonest individual offender. Ethambutol was most frequently involved in multiple drug-reactors. Median(IQR) time to a detectable reaction was 24(12-120) hours, 6/34(18%) being immediate (<6hours). Itch (65%), eosinophilia (56%), fever (41%), atypical lymphocytosis (41%), rash (38%), transaminitis (32%) and facial oedema (18%), singly or in combination were commonest features. Three reactions, one epidermal necrolysis and two liver derangements, were CTCAE grade 4 (life-threatening) events. No predictors of multiple drug-reactivity were identified, but multiple reactors were hospitalised significantly longer, 125(100-134) versus 60(45-80) days. CONCLUSIONS: SADC optimises FLTD reinitiation. However, timing, clinical presentation and severity of SADC-associated reactions following FLTD-associated DRESS is markedly heterogenous. Additionally, multiple drug-reactors are a complex group requiring longer hospitalisation, and without routine biomarkers to differentiate true multiple drug hypersensitivity from non-specific flare-ups and guide long-term drug avoidance strategies.

Long-term HIV and tuberculosis outcomes in patients hospitalised with severe cutaneous adverse reactions.

Background: Treatment-limiting severe cutaneous adverse reactions (SCAR) occur more commonly amongst persons with HIV-associated tuberculosis (TB). The impact of SCAR on long-term HIV/TB outcomes is unknown. Methods: Patients with TB and/or HIV admitted to Groote Schuur Hospital, Cape Town, South Africa with SCAR between 1/10/2018 and 30/09/2021 were eligible. Follow-up data was collected for 6- and 12-month outcomes: mortality, TB and antiretroviral therapy (ART) regimen changes, TB treatment completion, and CD4 count recovery. Results: Forty-eight SCAR admissions included: 34, 11, and 3 HIV-associated TB, HIV-only and TB-only patients with 32, 13 and 3 cases of drug reaction with eosinophilia and systemic symptoms, Stevens-Johnson syndrome/toxic epidermal necrolysis and generalised bullous fixed-drug eruption respectively. Nine (19%), all HIV-positive (eight co-infected with TB), were deceased at 12-months, and 12(25%) were lost to follow-up. Amongst TB-SCAR patients, seven (21%) were discharged on all four first-line anti-TB drugs (FLTD), while 12(33%) had regimens with no FLTDs; 24/37(65%) completed TB treatment. Amongst HIV-SCAR patients, 10/31(32%) changed ART regimen. If retained in care (24/36), median (IQR) CD4 counts increased at 12-months post-SCAR (115(62-175) vs. 319(134-439) cells/uL). Conclusion: SCAR admission amongst patients with HIV-associated TB results in substantial mortality, and considerable treatment complexity. However, if retained in care, TB regimens are successfully completed, and immune recovery is good despite SCAR.

Post-acute phase and sequelae management of epidermal necrolysis: an international, multidisciplinary DELPHI-based consensus.

BACKGROUND: Long-term sequelae are frequent and often disabling after epidermal necrolysis (Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN)). However, consensus on the modalities of management of these sequelae is lacking. OBJECTIVES: We conducted an international multicentric DELPHI exercise to establish a multidisciplinary expert consensus to standardize recommendations regarding management of SJS/TEN sequelae. METHODS: Participants were sent a survey via the online tool "Survey Monkey" consisting of 54 statements organized into 8 topics: general recommendations, professionals involved, skin, oral mucosa and teeth, eyes, genital area, mental health, and allergy workup. Participants evaluated the level of appropriateness of each statement on a scale of 1 (extremely inappropriate) to 9 (extremely appropriate). Results were analyzed according to the RAND/UCLA Appropriateness Method. RESULTS: Fifty-two healthcare professionals participated. After the first round, a consensus was obtained for 100% of 54 initially proposed statements (disagreement index < 1). Among them, 50 statements were agreed upon as 'appropriate'; four statements were considered 'uncertain', and ultimately finally discarded. CONCLUSIONS: Our DELPHI-based expert consensus should help guide physicians in conducting a prolonged multidisciplinary follow-up of sequelae in SJS-TEN.

Supportive care in the acute phase of Stevens-Johnson syndrome and toxic epidermal necrolysis: an international, multidisciplinary Delphi-based consensus.

BACKGROUND: Supportive care is the cornerstone of management of adult and paediatric Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN). However, consensus on the modalities of supportive care is lacking. OBJECTIVES: Our aim in this international multicentric Delphi exercise was to establish a multidisciplinary expert consensus to standardize recommendations regarding supportive care in the acute phase of SJS/TEN. METHODS: Participants were sent a survey via the online tool SurveyMonkey, consisting of 103 statements organized into 11 topics: multidisciplinary team composition, suspect drug management, infection prevention, fluid resuscitation and prevention of hypothermia, nutritional support, pain and psychological distress management, management of acute respiratory failure, local skincare, ophthalmological management, management of other mucosa, and additional measures. Participants evaluated the level of appropriateness of each statement on a scale of 1 (extremely inappropriate) to 9 (extremely appropriate). The results were analysed according to the RAND/UCLA Appropriateness Method. RESULTS: Forty-five participants from 13 countries (on three continents) participated. After the first round, a consensus was obtained for 82.5% of the 103 initially proposed statements. After the second round, a final consensus was obtained for 102 statements. CONCLUSIONS: We have reached an international Delphi-based consensus on best supportive care practice for SJS/TEN. Our expert consensus should help guide physicians in treating patients with SJS/TEN and thereby improve short-term prognosis and the risk of sequelae.

HLAs: Key regulators of T-cell-mediated drug hypersensitivity.

Adverse drug reactions (ADR) can be broadly categorised as either on-target or off-target. On-target ADRs arise as a direct consequence of the pharmacological properties of the drug and are therefore predictable and dose-dependent. On-target ADRs comprise the majority (>80%) of ADRs, relate to the drug's interaction with its known pharmacological target and are a result of a complex interplay of genetic and ecologic factors. In contrast, off-target ADRs, including immune-mediated ADRs (IM-ADRs), are due to unintended pharmacological interactions such as inadvertent ligation of host cell receptors or non-pharmacological interactions mediated through an adaptive immune response. IM-ADRs can be classified according to the primary immune cell involved and include B-cell-mediated (Gell-Coombs type I-III reactions) and T-cell-mediated (Gell-Coombs type IV or delayed hypersensitivity) reactions. IM-ADRs mediated by T cells are associated with phenotypically distinct clinical diagnoses and can vary from a mild delayed rash to a life-threatening cutaneous, systemic or organ disease, such as Stephen Johnson syndrome/toxic epidermal necrolysis, drug reaction with eosinophilia and systemic symptoms and drug-induced liver disease. T-cell-mediated ADRs are strongly linked to the carriage of particular HLA risk alleles which are in the case of abacavir hypersensitivity and HLA-B*57:01 has led to translation into the clinic as a routine screening test. In this review, we will discuss the immunogenetics and pathogenesis of IM-ADRs and how HLA associations inform both pre-drug screening strategies and mechanistic understanding.

Recent advances in the understanding of severe cutaneous adverse reactions.

Severe cutaneous adverse reactions (SCARs) encompass a heterogeneous group of delayed hypersensitivity reactions, which are most frequently caused by drugs. Our understanding of several aspects of SCAR syndromes has evolved considerably over the last decade. This review explores evolving knowledge of the immunopathogenic mechanisms, pharmacogenomic associations, in vivo and ex vivo diagnostics for causality assessment, and medication cross-reactivity data related to SCAR syndromes. Given the rarity and severity of these diseases, multidisciplinary collaboration through large international, national and/or multicentre networks to collect prospective data on patients with SCAR syndromes should be prioritized. This will further enhance a systematized framework for translating epidemiological, clinical and immunopathogenetic advances into preventive efforts and improved outcomes for patients.

Clinical Pharmacogenetics Implementation Consortium (CPIC) guidelines for human leukocyte antigen B (HLA-B) genotype and allopurinol dosing: 2015 update.

The Clinical Pharmacogenetics Implementation Consortium (CPIC) Guidelines for HLA-B*58:01 Genotype and Allopurinol Dosing was originally published in February 2013. We reviewed the recent literature and concluded that none of the evidence would change the therapeutic recommendations in the original guideline; therefore, the original publication remains clinically current. However, we have updated the Supplemental Material and included additional resources for applying CPIC guidelines into the electronic health record. Up-to-date information can be found at PharmGKB (http://www.pharmgkb.org).

Initiating allopurinol therapy: do we need to know the patient's human leucocyte antigen status?

AIMS: Allopurinol hypersensitivity (AH) can rarely be manifest as Stevens-Johnson syndrome (SJS) or toxic epidermal necrolysis (TEN) that have high mortality rates. Less serious, but still significant, skin and systemic hypersensitivity reactions form part of the AH spectrum. One hundred per cent of Han Chinese with SJS/TEN due to allopurinol have been found to be at least heterozygous for HLA-B*5801, the carriage rate for this allele in the Han Chinese population being about 15%. The association has been found to be weaker in Caucasians whose HLA-B*5801 carriage rate is less than 6%. We examined the relationship between the different skin hypersensitivity reactions to allopurinol and the HLA-B locus in Australian patients. METHODS: We examined 23 patients referred with AH. RESULTS: Five of six Australian SJS/TEN patients were heterozygous for HLA-B*5801 and four were of South-East Asian origin. Five AH patients without SJS/TEN were all Caucasian and only one of these was positive for HLA-B*5801. Twelve patients with allopurinol-induced maculopapular exanthema were negative for HLA-B*5801, including one South-East Asian. CONCLUSIONS: Cases of AH manifesting as SJS/TENS in Australians are more likely to be in those of Asian heritage. The place of routine testing for HLA-B*5801 prior to commencing allopurinol therapy requires further investigation. However, Han Chinese origin patients commencing allopurinol might be informed of the test and may elect to have it performed as there are alternative hypouricaemic medicines, such as probenecid thereby reducing the risk of a catastrophic reaction to allopurinol.

N2-dependent growth and nitrogenase activity in the metal-metabolizing bacteria, Geobacter and Magnetospirillum species.

Cells of Geobacter metallireducens, Magnetospirillum strain AMB-1, Magnetospirillum magnetotacticum and Magnetospirillum gryphiswaldense showed N2-dependent growth, the first anaerobically with Fe(III) as the electron acceptor, and the latter three species microaerobically in semi-solid oxygen gradient cultures. Cells of the Magnetospirillum species grown with N2 under microaerobic conditions were magnetotactic and therefore produced magnetosomes. Cells of Geobacter metallireducens reduced acetylene to ethylene (11.5+/-5.9 nmol C2H4 produced min(-1) mg(-1) cell protein) while growing with Fe(III) as the electron acceptor in anaerobic growth medium lacking a fixed nitrogen source. Cells of the Magnetospirillum species, grown in a semi-solid oxygen gradient medium, also reduced acetylene at comparable rates. Uncut chromosomal and fragments from endonuclease-digested chromosomal DNA from these species, as well as Geobacter sulphurreducens organisms, hybridized with a nifHDK probe from Rhodospirillum rubrum, indicating the presence of these nitrogenase structural genes in these organisms. The evidence presented here shows that members of the metal-metabolizing genera, Geobacter and Magnetospirillum, fix atmospheric dinitrogen.

Bacterial meningitis in children and adults. Changes in community-acquired disease may affect patient care.

Despite improved understanding of how bacterial meningitis develops, the infection remains a potentially life-threatening emergency capable of causing significant morbidity and mortality. Since the introduction and widespread use of H influenzae type b vaccine in infancy and childhood in North America, the epidemiology of community-acquired bacterial meningitis has changed. S pneumoniae is now the most common cause in children and adults overall, although N meningitidis causes most disease in patients between ages 2 and 18 years. Broad-spectrum cephalosporins (eg, ceftriaxone, cefotaxime) are considered the agents of choice for empirical treatment of bacterial meningitis. However, use of these agents will have to be reconsidered if the incidence of invasive infection from drug-resistant S pneumoniae continues to increase. The role of adjunctive corticosteroid therapy needs to be better defined. Improved conjugate pneumococcal and meningococcal vaccines may soon make bacterial meningitis a preventable disease.

The effect of exercise on lymphocyte redistribution and leucocyte function in asymptomatic HIV-infected subjects.

This study was undertaken to examine the responsiveness of circulating leucocyte and lymphocyte populations to the physiological demands of exercise in asymptomatic HIV-infected subjects with CD4+ counts greater than 500/microliter. Thirteen subjects infected with HIV and 14 control subjects underwent 20 min of defined moderate exercise at estimated 65% of their maximal ventilatory capacity on a bicycle ergometer. Blood samples were obtained for serum cortisol, norepinephrine, lymphocyte subsets (CD4, CD8, CD19, CD16-CD56), and phagocytic function at rest immediately after exercise and 20 min following the cessation of the exercise. The HIV-infected subjects had increased circulating concentrations of CD8 cells (p = .007) and CD16-CD56+ NK cells (p = .02) in response to the exercise, whereas the control group did not. There was a greater increase in monocyte respiratory burst activity following recovery from exercise in the control subjects (p = .016) but not in the HIV-infected subjects. The control subjects experienced an increase in serum cortisol in response to the exercise (p = .006), but the HIV-infected subjects did not. Our results show that the changes in the distribution and function of circulating leucocytes and adrenal neuroendocrine responses to moderate exercise differ in asymptomatic HIV-infected and control subjects.

Failure of combined chloroquine and high-dose primaquine therapy for Plasmodium vivax malaria acquired in Guyana, South America.

The presence of chloroquine-resistant Plasmodium vivax malaria in the New World has been suspected but not confirmed. We report the cases of three patients who acquired vivax malaria in Guyana, South America, and for whom standard chloroquine therapy (25 mg/kg) failed despite therapeutic blood levels. The optimal treatment of chloroquine-resistant P. vivax malaria is unknown, but recent studies suggest that a combination of chloroquine (25 mg/kg) and high-dose primaquine (2.5 mg/kg over 48 hours) is effective therapy. Two of our patients had recurrences of P. vivax malaria 6-8 weeks after receiving directly observed therapy with this combination. These cases confirm the presence of chloroquine-resistant P. vivax in Guyana and emphasize the need for better treatment regimens for chloroquine-resistant and primaquine-resistant P. vivax malaria.

Failure of combined choroquine and high-dose primaquine therapy for Plasmodium vivax malaria acquired in Guyana, South America

The presence of chloroquine-resistant Plasmodium vivax malaria in the New World has been suspected but not confirmed. We report the cases of three patients who acquired vivax malaria in Guyana, South America, and for whom standard chloroquine therapy (25mg/kg) failed despite therapeutic blood levels. The optimal treatment of Chloroquine-resistant P. vivax malaria is unknown, but recent studies suggest that a combination of chloroquine (25 mg/kg) and high-dose primaquine (2.5 mg/kg over 48 hours) is effective therapy. Two of our patients had recurrences of P. vivax malaria 6-8 weeks after receiving directly observed therapy with this combination. These cases confirm the presence of chloroquine-resistant P. vivax in Guyana and emphasize the need for better treatment regimens for chloroquine-resistant and primaquine-resistant P. vivax malaria.(AU)

Isolation of Geobacter species from diverse sedimentary environments.

In an attempt to better understand the microorganisms responsible for Fe(III) reduction in sedimentary environments, Fe(III)-reducing microorganisms were enriched for and isolated from freshwater aquatic sediments, a pristine deep aquifer, and a petroleum-contaminated shallow aquifer. Enrichments were initiated with acetate or toluene as the electron donor and Fe(III) as the electron acceptor. Isolations were made with acetate or benzoate. Five new strains which could obtain energy for growth by dissimilatory Fe(III) reduction were isolated. All five isolates are gram-negative strict anaerobes which grow with acetate as the electron donor and Fe(III) as the electron acceptor. Analysis of the 16S rRNA sequence of the isolated organisms demonstrated that they all belonged to the genus Geobacter in the delta subdivision of the Proteobacteria. Unlike the type strain, Geobacter metallireducens, three of the five isolates could use H2 as an electron donor for Fe(III) reduction. The deep subsurface isolate is the first Fe(III) reducer shown to completely oxidize lactate to carbon dioxide, while one of the freshwater sediment isolates is only the second Fe(III) reducer known that can oxidize toluene. The isolation of these organisms demonstrates that Geobacter species are widely distributed in a diversity of sedimentary environments in which Fe(III) reduction is an important process.

Phylogenetic analysis of dissimilatory Fe(III)-reducing bacteria.

Evolutionary relationships among strictly anaerobic dissimilatory Fe(III)-reducing bacteria obtained from a diversity of sedimentary environments were examined by phylogenetic analysis of 16S rRNA gene sequences. Members of the genera Geobacter, Desulfuromonas, Pelobacter, and Desulfuromusa formed a monophyletic group within the delta subdivision of the class Proteobacteria. On the basis of their common ancestry and the shared ability to reduce Fe(III) and/or S0, we propose that this group be considered a single family, Geobacteraceae. Bootstrap analysis, characteristic nucleotides, and higher-order secondary structures support the division of Geobacteraceae into two subgroups, designated the Geobacter and Desulfuromonas clusters. The genus Desulfuromusa and Pelobacter acidigallici make up a distinct branch within the Desulfuromonas cluster. Several members of the family Geobacteraceae, none of which reduce sulfate, were found to contain the target sequences of probes that have been previously used to define the distribution of sulfate-reducing bacteria and sulfate-reducing bacterium-like microorganisms. The recent isolations of Fe(III)-reducing microorganisms distributed throughout the domain Bacteria suggest that development of 16S rRNA probes that would specifically target all Fe(III) reducers may not be feasible. However, all of the evidence suggests that if a 16S rRNA sequence falls within the family Geobacteraceae, then the organism has the capacity for Fe(III) reduction. The suggestion, based on geological evidence, that Fe(III) reduction was the first globally significant process for oxidizing organic matter back to carbon dioxide is consistent with the finding that acetate-oxidizing Fe(III) reducers are phylogenetically diverse.

Fe(III) and S0 reduction by Pelobacter carbinolicus.

There is a close phylogenetic relationship between Pelobacter species and members of the genera Desulfuromonas and Geobacter, and yet there has been a perplexing lack of physiological similarities. Pelobacter species have been considered to have a fermentative metabolism. In contrast, Desulfuromonas and Geobacter species have a respiratory metabolism with Fe(III) serving as the common terminal electron acceptor in all species. However, the ability of Pelobacter species to reduce Fe(III) had not been previously evaluated. When a culture of Pelobacter carbinolicus that had grown by fermentation of 2,3-butanediol was inoculated into the same medium supplemented with Fe(III), the Fe(III) was reduced. There was less accumulation of ethanol and more production of acetate in the presence of Fe(III). P. carbinolicus grew with ethanol as the sole electron donor and Fe(III) as the sole electron acceptor. Ethanol was metabolized to acetate. Growth was also possible on Fe(III) with the oxidation of propanol to propionate or butanol to butyrate if acetate was provided as a carbon source. P. carbinolicus appears capable of conserving energy to support growth from Fe(III) respiration as it also grew with H2 or formate as the electron donor and Fe(III) as the electron acceptor. Once adapted to Fe(III) reduction, P. carbinolicus could also grow on ethanol or H2 with S0 as the electron acceptor. P. carbinolicus did not contain detectable concentrations of the c-type cytochromes that previous studies have suggested are involved in electron transport to Fe(III) in other organisms that conserve energy to support growth from Fe(III) reduction.(ABSTRACT TRUNCATED AT 250 WORDS)

Novel processes for anaerobic sulfate production from elemental sulfur by sulfate-reducing bacteria.

Sulfate reducers and related organisms which had previously been found to reduce Fe(III) with H(2) or organic electron donors oxidized S to sulfate when Mn(IV) was provided as an electron acceptor. Organisms catalyzing this reaction in washed cell suspensions included Desulfovibrio desulfuricans, Desulfomicrobium baculatum, Desulfobacterium autotrophicum, Desulfuromonas acetoxidans, and Geobacter metallireducens. These organisms produced little or no sulfate from S with Fe(III) as a potential electron acceptor or in the absence of an electron acceptor. In detailed studies with Desulfovibrio desulfuricans, the stoichiometry of sulfate and Mn(II) production was consistent with the reaction S + 3 MnO(2) + 4H-->SO(4) + 3Mn(II) + 2H(2)O. None of the organisms evaluated could be grown with S as the sole electron donor and Mn(IV) as the electron acceptor. In contrast to the other sulfate reducers evaluated, Desulfobulbus propionicus produced sulfate from S in the absence of an electron acceptor and Fe(III) oxide stimulated sulfate production. Sulfide also accumulated in the absence of Mn(IV) or Fe(III). The stoichiometry of sulfate and sulfide production indicated that Desulfobulbus propionicus disproportionates S as follows: 4S + 4H(2)O-->SO(4) + 3HS + 5 H. Growth of Desulfobulbus propionicus with S as the electron donor and Fe(III) as a sulfide sink and/or electron acceptor was very slow. The S oxidation coupled to Mn(IV) reduction described here provides a potential explanation for the Mn(IV)-dependent sulfate production that previous studies have observed in anoxic marine sediments. Desulfobulbus propionicus is the first example of a pure culture known to disproportionate S.

Reduction of Chromate by Desulfovibrio vulgaris and Its c(3) Cytochrome.

Washed cell suspensions of Desulfovibrio vulgaris rapidly reduced Cr(VI) to Cr(III) with H(2) as the electron donor. The c(3) cytochrome from this organism functioned as a Cr(VI) reductase. D. vulgaris may have advantages over previously described Cr(VI) reducers for the bioremediation of Cr(VI)-contaminated waters.