RESUMO
Cough, a hallmark of tuberculosis, transmits the disease. Ruhl et al. find that a Mycobacterium tuberculosis (Mtb)-specific lipid, SL-1, stimulates human nociceptive neurons and makes guinea pigs cough. Mtb extract, but not SL-1, also stimulates non-nociceptive neurons that participate in the cough reflex, suggesting additional cough-inducing mechanisms.
Assuntos
Mycobacterium tuberculosis , Tuberculose , Animais , Tosse , Cobaias , Humanos , Lipídeos , NociceptoresRESUMO
Treatment of tuberculosis, a complex granulomatous disease, requires long-term multidrug therapy to overcome tolerance, an epigenetic drug resistance that is widely attributed to nonreplicating bacterial subpopulations. Here, we deploy Mycobacterium marinum-infected zebrafish larvae for in vivo characterization of antitubercular drug activity and tolerance. We describe the existence of multidrug-tolerant organisms that arise within days of infection, are enriched in the replicating intracellular population, and are amplified and disseminated by the tuberculous granuloma. Bacterial efflux pumps that are required for intracellular growth mediate this macrophage-induced tolerance. This tolerant population also develops when Mycobacterium tuberculosis infects cultured macrophages, suggesting that it contributes to the burden of drug tolerance in human tuberculosis. Efflux pump inhibitors like verapamil reduce this tolerance. Thus, the addition of this currently approved drug or more specific efflux pump inhibitors to standard antitubercular therapy should shorten the duration of curative treatment.
Assuntos
Tolerância a Medicamentos , Macrófagos/microbiologia , Mycobacterium marinum/fisiologia , Mycobacterium tuberculosis/fisiologia , Tuberculose/microbiologia , Animais , Antituberculosos/uso terapêutico , Proteínas de Bactérias/antagonistas & inibidores , Proteínas de Bactérias/metabolismo , Modelos Animais de Doenças , Granuloma/fisiopatologia , Humanos , Larva/microbiologia , Moduladores de Transporte de Membrana/farmacologia , Proteínas de Membrana Transportadoras/metabolismo , Infecções por Mycobacterium não Tuberculosas/tratamento farmacológico , Infecções por Mycobacterium não Tuberculosas/patologia , Infecções por Mycobacterium não Tuberculosas/fisiopatologia , Mycobacterium marinum/efeitos dos fármacos , Tuberculose/tratamento farmacológico , Tuberculose/patologia , Tuberculose/fisiopatologia , Verapamil/farmacologia , Peixe-Zebra/microbiologiaRESUMO
Tuberculosis treatment requires months-long combination chemotherapy with multiple drugs, with shorter treatments leading to relapses. A major impediment to shortening treatment is that Mycobacterium tuberculosis becomes tolerant to the administered drugs, starting early after infection and within days of infecting macrophages. Multiple lines of evidence suggest that macrophage-induced drug tolerance is mediated by mycobacterial drug efflux pumps. Here, using assays to directly measure drug efflux, we find that M. tuberculosis transports the first-line antitubercular drug rifampicin through a proton gradient-dependent mechanism. We show that verapamil, a known efflux pump inhibitor, which inhibits macrophage-induced rifampicin tolerance, also inhibits M.tuberculosis rifampicin efflux. As with macrophage-induced tolerance, the calcium channel-inhibiting property of verapamil is not required for its inhibition of rifampicin efflux. By testing verapamil analogs, we show that verapamil directly inhibits M. tuberculosis drug efflux pumps through its human P-glycoprotein (PGP)-like inhibitory activity. Screening commonly used drugs with incidental PGP inhibitory activity, we find many inhibit rifampicin efflux, including the proton pump inhibitors (PPIs) such as omeprazole. Like verapamil, the PPIs inhibit macrophage-induced rifampicin tolerance as well as intramacrophage growth, which has also been linked to mycobacterial efflux pump activity. Our assays provide a facile screening platform for M. tuberculosis efflux pump inhibitors that inhibit in vivo drug tolerance and growth.
Assuntos
Mycobacterium tuberculosis , Tuberculose , Humanos , Rifampina/farmacologia , Inibidores da Bomba de Prótons/farmacologia , Antituberculosos/farmacologia , Verapamil/farmacologia , Macrófagos , Tuberculose/tratamento farmacológico , Tolerância a Medicamentos , Proteínas de Bactérias , Testes de Sensibilidade MicrobianaRESUMO
Biallelic mutations in the glucocerebrosidase (GBA1) gene cause Gaucher disease, characterized by lysosomal accumulation of glucosylceramide and glucosylsphingosine in macrophages. Gaucher and other lysosomal diseases occur with high frequency in Ashkenazi Jews. It has been proposed that the underlying mutations confer a selective advantage, in particular conferring protection against tuberculosis. Here, using a zebrafish Gaucher disease model, we find that the mutation GBA1 N370S, predominant among Ashkenazi Jews, increases resistance to tuberculosis through the microbicidal activity of glucosylsphingosine in macrophage lysosomes. Consistent with lysosomal accumulation occurring only in homozygotes, heterozygotes remain susceptible to tuberculosis. Thus, our findings reveal a mechanistic basis for protection against tuberculosis by GBA1 N370S and provide biological plausibility for its selection if the relatively mild deleterious effects in homozygotes were offset by significant protection against tuberculosis, a rampant killer of the young in Europe through the Middle Ages into the 19th century.
Assuntos
Doença de Gaucher , Tuberculose , Animais , Doença de Gaucher/genética , Peixe-Zebra/genética , Glucosilceramidase/genética , Mutação , Tuberculose/genética , Tuberculose/prevenção & controleRESUMO
Amoxicillin-clavulanate (AMC) is among the most frequently prescribed antibiotics globally. It has broad antibacterial activity against gram-positive, gram-negative, and anaerobic bacteria, and has been utilized to treat infections caused by a broad range of pathogens. AMC breakpoints against Enterobacterales were initially set in the 1980s but since then increases in antibiotic resistance, advances in pharmacokinetic (PK)/pharmacodynamic (PD) analyses, and publication of additional clinical data prompted a reassessment by the Clinical and Laboratory Standards Institute (CLSI) Subcommittee on Antimicrobial Susceptibility Testing. Based on this contemporary reappraisal, the CLSI retained the Enterobacterales breakpoints but revised comments regarding dosing associated with use of the AMC breakpoints in the 2022 supplement of M100. This viewpoint provides insight into the CLSI breakpoint reevaluation process and summarizes the data and rationale used to support these revisions to the AMC Enterobacterales breakpoint.
RESUMO
Adjunctive treatment with antiinflammatory corticosteroids like dexamethasone increases survival in tuberculosis meningitis. Dexamethasone responsiveness associates with a C/T variant in Leukotriene A4 Hydrolase (LTA4H), which regulates expression of the proinflammatory mediator leukotriene B4 (LTB4). TT homozygotes, with increased expression of LTA4H, have the highest survival when treated with dexamethasone and the lowest survival without. While the T allele is present in only a minority of the world's population, corticosteroids confer modest survival benefit worldwide. Using Bayesian methods, we examined how pretreatment levels of cerebrospinal fluid proinflammatory cytokines affect survival in dexamethasone-treated tuberculous meningitis. LTA4H TT homozygosity was associated with global cytokine increases, including tumor necrosis factor. Association between higher cytokine levels and survival extended to non-TT patients, suggesting that other genetic variants may also induce dexamethasone-responsive pathological inflammation. These findings warrant studies that tailor dexamethasone therapy to pretreatment cerebrospinal fluid cytokine concentrations, while searching for additional genetic loci shaping the inflammatory milieu.
Assuntos
Citocinas/líquido cefalorraquidiano , Dexametasona/administração & dosagem , Epóxido Hidrolases/genética , Variação Genética , Tuberculose Meníngea , Intervalo Livre de Doença , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Taxa de Sobrevida , Tuberculose Meníngea/líquido cefalorraquidiano , Tuberculose Meníngea/tratamento farmacológico , Tuberculose Meníngea/genética , Tuberculose Meníngea/mortalidadeRESUMO
A fatal case of Legionnaires' disease caused by Legionella jamestowniensis is reported in a severely immunocompromised patient with metastatic hepatocellular carcinoma, and liver and kidney transplants. L. jamestowniensis was cultured from two separate respiratory tract specimens and a PCR test for Legionella species was also positive from the same specimens. This is apparently the first reported case of human infection caused by L. jamestowniensis.
Assuntos
Legionella/isolamento & purificação , Doença dos Legionários/microbiologia , Pneumonia Bacteriana/microbiologia , Humanos , Hospedeiro Imunocomprometido , Legionella/genética , Legionelose/microbiologia , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase/métodosRESUMO
We report a case of persistent Rhodopseudomonas bacteremia in a patient two months after an allogeneic bone marrow transplant for acute myeloid leukemia. The bacteremia persisted until IV catheter removal. To our knowledge, this is the first report of Rhodopseudomonas causing infection in humans.
Assuntos
Bacteriemia/microbiologia , Rodopseudomonas/patogenicidade , Adulto , Antibacterianos/uso terapêutico , Bacteriemia/tratamento farmacológico , Transplante de Medula Óssea/métodos , Feminino , Humanos , Leucemia Mieloide Aguda/microbiologia , Rodopseudomonas/efeitos dos fármacosAssuntos
Antituberculosos/história , Antituberculosos/normas , Antituberculosos/uso terapêutico , Tuberculose Latente/tratamento farmacológico , Tuberculose Latente/história , Mycobacterium tuberculosis/efeitos dos fármacos , Guias de Prática Clínica como Assunto , Feminino , História do Século XIX , História do Século XX , História do Século XXI , Humanos , Tuberculose Latente/epidemiologia , Masculino , Estados Unidos/epidemiologiaRESUMO
Mixed-population (heterogeneous) enterococcal bacteremia (MEB) is rarely reported. Based on one occasion in which Vitek2 missed a vancomycin-resistant subpopulation isolated from a patient, we developed a simple method to detect this subpopulation and determined MEB frequency. The four patients presented here had either Enterococcus faecium or Enterococcus faecalis bacteremia caused by both vancomycin-resistant enterococci (VRE) and vancomycin-susceptible enterococci (VSE). No prior common antibiotic therapy was observed, and bacteremia resolved with daptomycin, gentamicin, and/or linezolid treatment. In two cases, VRE presence was missed by Vitek2. To detect the VRE subpopulation, tryptic soy broth was inoculated from positive blood cultures and a saline suspension was inoculated to a vancomycin (6-µg/ml) (V6) plate. Two isolates from each patient were studied further. Relatedness was assessed by multilocus sequence typing, fitness was evaluated by growth curve and competition assays, and vanA presence was determined by PCR. MEB represented â¼5% of all enterococcal bacteremias. All VRE subpopulations grew on V6 plates but were missed in two instances by Vitek2. VRE and VSE isolates from each patient were closely related and did not differ in overall fitness. All four VRE isolates and 2/4 VSE isolates were vanA positive. MEBs occur regardless of prior antimicrobial therapy, are relatively common in our hospital, and are important to detect. As far as we know, this study is the first to report heterogeneous E. faecalis bacteremia. There is a simple method to detect VRE subpopulations that may be missed by Vitek2.
Assuntos
Bacteriemia/epidemiologia , Coinfecção/epidemiologia , Enterococcus faecalis/isolamento & purificação , Enterococcus faecium/isolamento & purificação , Infecções por Bactérias Gram-Positivas/epidemiologia , Acetamidas/uso terapêutico , Idoso , Antibacterianos/uso terapêutico , Bacteriemia/diagnóstico , Bacteriemia/microbiologia , Coinfecção/diagnóstico , Coinfecção/microbiologia , Daptomicina/uso terapêutico , Enterococcus faecalis/classificação , Enterococcus faecalis/efeitos dos fármacos , Enterococcus faecalis/genética , Enterococcus faecium/classificação , Enterococcus faecium/efeitos dos fármacos , Enterococcus faecium/genética , Gentamicinas/uso terapêutico , Infecções por Bactérias Gram-Positivas/diagnóstico , Infecções por Bactérias Gram-Positivas/microbiologia , Humanos , Linezolida , Masculino , Pessoa de Meia-Idade , Tipagem de Sequências Multilocus , Oxazolidinonas/uso terapêutico , Prevalência , Resultado do Tratamento , Resistência a VancomicinaRESUMO
We transitioned laboratory-developed PCR assays for herpes simplex virus 1 (HSV-1), HSV-2, and varicella-zoster virus (VZV) to the BD Max system by using BD Max open system reagents. After optimization, the agreement with the reference PCR assay was 100% (123/123) for HSV-1, 96.7% (119/123) for HSV-2, and 100% (60/60) for VZV using retrospective clinical samples.
Assuntos
Herpes Simples/diagnóstico , Herpes Zoster/diagnóstico , Herpesvirus Humano 3/isolamento & purificação , Técnicas de Diagnóstico Molecular/métodos , Reação em Cadeia da Polimerase em Tempo Real/métodos , Simplexvirus/isolamento & purificação , Pele/virologia , Herpes Simples/virologia , Herpes Zoster/virologia , Herpesvirus Humano 3/genética , Humanos , Simplexvirus/genética , Virologia/métodosRESUMO
The accurate performance of the Vitek 2 GP67 card for detecting methicillin-resistant coagulase-negative staphylococci (CoNS) is not known. We prospectively determined the ability of the Vitek 2 GP67 card to accurately detect methicillin-resistant CoNS, with mecA PCR results used as the gold standard for a 4-month period in 2012. Included in the study were 240 consecutively collected nonduplicate CoNS isolates. Cefoxitin susceptibility by disk diffusion testing was determined for all isolates. We found that the three tested systems, Vitek 2 oxacillin and cefoxitin testing and cefoxitin disk susceptibility testing, lacked specificity and, in some cases, sensitivity for detecting methicillin resistance. The Vitek 2 oxacillin and cefoxitin tests had very major error rates of 4% and 8%, respectively, and major error rates of 38% and 26%, respectively. Disk cefoxitin testing gave the best performance, with very major and major error rates of 2% and 24%, respectively. The test performances were species dependent, with the greatest errors found for Staphylococcus saprophyticus. While the 2014 CLSI guidelines recommend reporting isolates that test resistant by the oxacillin MIC or cefoxitin disk test as oxacillin resistant, following such guidelines produces erroneous results, depending on the test method and bacterial species tested. Vitek 2 cefoxitin testing is not an adequate substitute for cefoxitin disk testing. For critical-source isolates, mecA PCR, rather than Vitek 2 or cefoxitin disk testing, is required for optimal antimicrobial therapy.
Assuntos
Resistência a Meticilina , Testes de Sensibilidade Microbiana/métodos , Infecções Estafilocócicas/diagnóstico , Infecções Estafilocócicas/microbiologia , Staphylococcus/efeitos dos fármacos , Staphylococcus/isolamento & purificação , Cefoxitina/farmacologia , Coagulase/deficiência , Erros de Diagnóstico , Humanos , Oxacilina/farmacologia , Staphylococcus/classificaçãoRESUMO
Mycobacterium llatzerense was cultured from a subdiaphragmatic abscess. To our knowledge, this is the first report of isolation of this rapidly growing mycobacterium from a human. Growth characteristics and antimicrobial susceptibilities different from those previously reported for environmental isolates were observed.
Assuntos
Abscesso Abdominal/diagnóstico , Infecções por Mycobacterium não Tuberculosas/diagnóstico , Mycobacterium/isolamento & purificação , Abscesso Abdominal/microbiologia , Abscesso Abdominal/patologia , Antibacterianos/farmacologia , Análise por Conglomerados , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Feminino , Humanos , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Dados de Sequência Molecular , Mycobacterium/classificação , Mycobacterium/genética , Infecções por Mycobacterium não Tuberculosas/microbiologia , Infecções por Mycobacterium não Tuberculosas/patologia , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNARESUMO
The Bristol stool form scale classifies the relative density of stool samples. In a prospective cohort study, we investigated the associations between stool density, C. difficile assay positivity, hospital-onset C. difficile infection, complications, and severity of C. difficile. We describe associations between the Bristol score, assay positivity, and clinical C. difficile infection.
Assuntos
Clostridioides difficile/isolamento & purificação , Infecções por Clostridium/microbiologia , Infecções por Clostridium/patologia , Fezes/química , Fezes/microbiologia , Fenômenos Químicos , Infecções por Clostridium/diagnóstico , Estudos de Coortes , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Índice de Gravidade de DoençaRESUMO
The need for lengthy treatment to cure tuberculosis stems from phenotypic drug resistance, also known as drug tolerance, which has been previously attributed to slowed bacterial growth in vivo. We discuss recent findings that challenge this model and instead implicate macrophage-induced mycobacterial efflux pumps in antimicrobial tolerance. Although mycobacterial efflux pumps may have originally served to protect against environmental toxins, in the pathogenic mycobacteria, they appear to have been repurposed for intracellular growth. In this light, we discuss the potential of efflux pump inhibitors such as verapamil to shorten tuberculosis treatment by their dual inhibition of tolerance and growth.
Assuntos
Transportadores de Cassetes de Ligação de ATP/antagonistas & inibidores , Antituberculosos/farmacologia , Mycobacterium tuberculosis/efeitos dos fármacos , Tuberculose Pulmonar/tratamento farmacológico , Verapamil/farmacologia , Fatores de Virulência/antagonistas & inibidores , Transportadores de Cassetes de Ligação de ATP/genética , Transportadores de Cassetes de Ligação de ATP/metabolismo , Transporte Biológico , Bloqueadores dos Canais de Cálcio/farmacologia , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Sinergismo Farmacológico , Evolução Molecular , Expressão Gênica , Humanos , Macrófagos/efeitos dos fármacos , Macrófagos/microbiologia , Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/metabolismo , Fatores de Tempo , Tuberculose Pulmonar/microbiologia , Fatores de Virulência/genética , Fatores de Virulência/metabolismoRESUMO
Induction of mycobacterial efflux pumps is a cause of Mycobacterium tuberculosis (Mtb) drug tolerance, a barrier to shortening antitubercular treatment. Verapamil inhibits Mtb efflux pumps that mediate tolerance to rifampin, a cornerstone of tuberculosis (TB) treatment. Verapamil's mycobacterial efflux pump inhibition also limits Mtb growth in macrophages in the absence of antibiotic treatment. These findings suggest that verapamil could be used as an adjunctive therapy for TB treatment shortening. However, verapamil is rapidly and substantially metabolized when co-administered with rifampin. We determined in a dose-escalation clinical trial of persons with pulmonary TB that rifampin-induced clearance of verapamil can be countered without toxicity by the administration of larger than usual doses of verapamil. An oral dosage of 360 mg sustained-release (SR) verapamil given every 12 hours concomitantly with rifampin achieved median verapamil exposures of 903.1 ng.h/mL (area under the curve (AUC)0-12 h ) in the 18 participants receiving this highest studied verapamil dose; these AUC findings are similar to those in persons receiving daily doses of 240 mg verapamil SR but not rifampin. Moreover, norverapamil:verapamil, R:S verapamil, and R:S norverapamil AUC ratios were all significantly greater than those of historical controls receiving SR verapamil in the absence of rifampin. Thus, rifampin administration favors the less-cardioactive verapamil metabolites and enantiomers that retain similar Mtb efflux inhibitory activity to verapamil, increasing overall benefit. Finally, rifampin exposures were 50% greater after verapamil administration, which may also be advantageous. Our findings suggest that a higher dosage of verapamil can be safely used as adjunctive treatment in rifampin-containing treatment regimens.