RESUMO
Coxiella burnetii, the causative agent of Q fever, survives and replicates in the acidic environment of monocytes/macrophages; hydroxychloroquine, through alkalinisation of the acidic vacuoles, is critical for the management of Q fever. In this study, a collection of C. burnetii strains isolated from human samples was tested to evaluate the in vitro minimum inhibitory concentrations (MICs) of doxycycline and hydroxychloroquine. Serial two-fold dilutions of doxycycline (0.25-8 mg/L) and hydroxychloroquine (0.25-4 mg/L) were added to C. burnetii-infected human embryonic lung (HEL) fibroblast cells after 48 h of incubation, in duplicate. DNA was detected by C. burnetii-specific semi-quantitative PCR with primers and probes designed for amplification of the IS1111 and IS30A spacers. A total of 29 C. burnetii isolates obtained from 29 patients were tested. Doxycycline MICs ranged from 0.25 mg/L to 0.5 mg/L and hydroxychloroquine MICs from 0.25 mg/L to >4 mg/L. Four C. burnetii stains had hydroxychloroquine MICs ≤ 1 mg/L. The concentration of hydroxychloroquine was associated with a significant decrease in C. burnetii DNA copies in HEL cells based on linear regression analysis (P= 0.01). Recommended serum concentrations of hydroxychloroquine significantly reduced the growth of C. burnetii. Moreover, some C. burnetii strains presented hydroxychloroquine MICs below the recommended serum concentrations, indicating that, for these cases, hydroxychloroquine treatment alone may even be effective.
Assuntos
Antibacterianos/farmacologia , Coxiella burnetii/efeitos dos fármacos , Fibroblastos/microbiologia , Hidroxicloroquina/farmacologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Células Cultivadas , Doxiciclina/farmacologia , Feminino , Humanos , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-IdadeAssuntos
Pulmão/microbiologia , Pulmão/patologia , Síndrome do Desconforto Respiratório/diagnóstico , Síndrome do Desconforto Respiratório/microbiologia , Tifo por Ácaros/diagnóstico , Tifo por Ácaros/microbiologia , Antibacterianos/uso terapêutico , Feminino , França , Humanos , Pessoa de Meia-Idade , Orientia tsutsugamushi , Síndrome do Desconforto Respiratório/tratamento farmacológico , Tifo por Ácaros/tratamento farmacológico , Resultado do TratamentoAssuntos
Sulfadiazina/farmacologia , Trimetoprima/farmacologia , Tropheryma/efeitos dos fármacos , Farmacorresistência Bacteriana Múltipla , Humanos , Testes de Sensibilidade Microbiana , Combinação Trimetoprima e Sulfametoxazol/uso terapêutico , Tropheryma/crescimento & desenvolvimento , Tropheryma/isolamento & purificação , Doença de Whipple/tratamento farmacológico , Doença de Whipple/microbiologiaRESUMO
The culture of fastidious microorganisms is a critical step in infectious disease studies. As a proof-of-concept experiment, we evaluated an empirical medium containing eukaryotic cell extracts for its ability to support the growth of Coxiella burnetii. Here, we demonstrate the exponential growth of several bacterial strains, including the C. burnetii Nine Mile phase I and phase II strains, and C. burnetii isolates from humans and animals. Low-oxygen-tension conditions and the presence of small hydrophilic molecules and short peptides were critical for facilitating growth. Moreover, bacterial antigenicity was conserved, revealing the potential for this culture medium to be used in diagnostic tests and in the elaboration of vaccines against C. burnetii. We were also able to grow the majority of previously tested intracellular and fastidious bacterial species, including Tropheryma whipplei, Mycobacterium bovis, Leptospira spp., Borrelia spp., and most putative bioterrorism agents. However, we were unable to culture Rickettsia africae and Legionella spp. in this medium. The versatility of this medium should encourage its use as a replacement for the cell-based culture systems currently used for growing several facultative and putative intracellular bacterial species.