RESUMO
BACKGROUND: Generally, pandemics such as COVID-19 take an enormous toll on people's lives. As the pandemic now turns to an endemic state, growing attention has been paid to the multiple adverse mental health and behavioral issues, such as suicidal ideation and substance use. However, the interplay of suicidality and substance misuse during the pandemic has been limited. We aimed to investigate the prevalence of co-occurrence of suicide ideation, alcohol and cannabis misuse, and the factors that are associated with these co-occurrences in the province of Saskatchewan during the COVID-19 pandemic. METHODS: We performed a multivariable trivariate probit regression on a sample of 666 Saskatchewan adolescents and adults (16 years or older), drawn from the cycle 10 data collection (March 2022) of the Mental Health Commission of Canada, and Canadian Centre on Substance Use and Addiction (MHCC-CCSA) dataset. RESULTS: The prevalence of suicidal ideation was higher among respondents who reported both problematic cannabis and alcohol use (25.8%) than single users of alcohol (23.2%) and cannabis (18.7%). Younger respondents (16-34 years) and those who reported recent changes in other substance use were independent factors that were associated with the common experience of suicide ideation, problematic cannabis, and alcohol use. Having a diagnosis of mental health disorders either before or during the pandemic, and the perceived inability to bounce back after the pandemic (low resilience) are strong correlates of suicidal ideation. Those who lived alone, between 35 and 55 years of age were more likely to report problematic alcohol use. Those who reported changes in alternative activities, who reported pandemic stress, and declared a LGBTQIA2S + identity had higher probability of problematic cannabis use. CONCLUSIONS: As the pandemic persists, improving access to suicide and substance use interventions for the vulnerable groups identified in this study may be impactful.
Assuntos
COVID-19 , Cannabis , Transtornos Relacionados ao Uso de Substâncias , Adulto , Adolescente , Humanos , Ideação Suicida , Pandemias , Prevalência , Saskatchewan/epidemiologia , COVID-19/epidemiologia , Transtornos Relacionados ao Uso de Substâncias/psicologia , Fatores de RiscoRESUMO
Several natural antimicrobial peptides (AMPs), including the novel semisynthetic lipoglycopeptide antibiotics telavancin, dalbavancin, and oritavancin, have been approved for clinical use to address the growing problem of multiple antibiotic-resistant Gram-positive bacterial infections. Nevertheless, the efficacy of these antibiotics has already been compromised. The SARS-CoV-2 pandemic led to the increased clinical use of all antibiotics, further promoting the development of bacterial resistance. Therefore, it is critical to gain a deeper understanding of the role of resistance mechanisms to minimize the consequential risks of long-term antibiotic use and misuse. Here, we summarize for the first time the current knowledge of resistance mechanisms that have been shown to cause resistance to clinically used AMPs, with particular focus on membrane proteins that have been reported to interfere with the activity of AMPs by affecting the binding of AMPs to bacteria.
Assuntos
COVID-19 , Infecções por Bactérias Gram-Positivas , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Peptídeos Antimicrobianos , Infecções por Bactérias Gram-Positivas/tratamento farmacológico , Infecções por Bactérias Gram-Positivas/metabolismo , Infecções por Bactérias Gram-Positivas/microbiologia , Humanos , Proteínas de Membrana , SARS-CoV-2RESUMO
Vga(A) protein variants confer different levels of resistance to lincosamides, streptogramin A, and pleuromutilins (LSAP) by displacing antibiotics from the ribosome. Here, we show that expression of vga(A) variants from Staphylococcus haemolyticus is regulated by cis-regulatory RNA in response to the LSAP antibiotics by the mechanism of ribosome-mediated attenuation. The specificity of induction depends on Vga(A)-mediated resistance rather than on the sequence of the riboregulator. Fine tuning between Vga(A) activity and its expression in response to the antibiotics may contribute to the selection of more potent Vga(A) variants because newly acquired mutation can be immediately phenotypically manifested.
Assuntos
Farmacorresistência Bacteriana Múltipla , Estreptogramina A , Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Lincosamidas , Macrolídeos , Ribossomos/genéticaRESUMO
The VanR-VanS two-component system is responsible for inducing resistance to glycopeptide antibiotics in various bacteria. We have performed a comparative study of the VanR-VanS systems from two streptomyces strains, Streptomyces coelicolor and Streptomyces toyocaensis, to characterize how the two proteins cooperate to signal the presence of antibiotics and to define the functional nature of each protein in each strain background. The results indicate that the glycopeptide antibiotic inducer specificity is determined solely by the differences between the amino acid sequences of the VanR-VanS two-component systems present in each strain rather than by any inherent differences in general cell properties, including cell wall structure and biosynthesis. VanR of S. coelicolor (VanRsc) functioned with either sensor kinase partner, while VanR of S. toyocaensis (VanRst) functioned only with its cognate partner, S. toyocaensis VanS (VanSst). In contrast to VanRsc, which is known to be capable of phosphorylation by acetylphosphate, VanRst could not be activated in vivo independently of a VanS sensor kinase. A series of amino acid sequence modifications changing residues in the N-terminal receiver (REC) domain of VanRst to the corresponding residues present in VanRsc failed to create a protein capable of being activated by VanS of S. coelicolor (VanSsc), which suggests that interaction of the response regulator with its cognate sensor kinase may require a region more extended than the REC domain. A T69S amino acid substitution in the REC domain of VanRst produced a strain exhibiting weak constitutive resistance, indicating that this particular amino acid may play a key role for VanS-independent phosphorylation in the response regulator protein.
Assuntos
Antibacterianos/farmacologia , Proteínas de Bactérias/metabolismo , Farmacorresistência Bacteriana Múltipla/genética , Histidina Quinase/metabolismo , Streptomyces coelicolor/efeitos dos fármacos , Fatores de Transcrição/metabolismo , Vancomicina/farmacologia , Sequência de Aminoácidos , Substituição de Aminoácidos/genética , Antibacterianos/metabolismo , Proteínas de Bactérias/genética , Ativação Enzimática , Regulação Bacteriana da Expressão Gênica , Histidina Quinase/genética , Regiões Promotoras Genéticas/genética , Streptomyces coelicolor/genética , Streptomyces coelicolor/metabolismo , Fatores de Transcrição/genética , Vancomicina/metabolismoRESUMO
The ABCF family protein Msr(A) confers high resistance to macrolides but only low resistance to ketolides in staphylococci. Mutations in conserved functional regions of ClpX as well as deletion of clpX significantly increased Msr(A)-mediated resistance to the ketolide antibiotic telithromycin. ClpX is the chaperone component of the ClpXP two-component proteolytic system. Nevertheless, no changes in resistance were observed in a clpP knockout strain expressing msr(A), demonstrating that ClpX affects Msr(A) independently of ClpP.
Assuntos
Antibacterianos/farmacologia , Cetolídeos/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Macrolídeos/farmacologia , MutaçãoRESUMO
Detailed mutational analysis examines the roles of individual residues of the Vga(A) linker in determining the antibiotic resistance phenotype. It defines a narrowed region of residues 212 to 220 whose composition determines the resistance specificity to lincosamides, pleuromutilins, and/or streptogramins A. From the analogy with the recently described function of the homologous ABC-F protein EttA as a translational factor, we infer that the Vga(A) linker interacts with the ribosome and directly or indirectly affects the binding of the respective antibiotic.
Assuntos
Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Microscopia Crioeletrônica , Diterpenos/farmacologia , Farmacorresistência Bacteriana Múltipla , Lincosamidas/farmacologia , Testes de Sensibilidade Microbiana , Compostos Policíclicos , Ribossomos/metabolismo , Estreptograminas/farmacologia , PleuromutilinasRESUMO
Peptides that form transmembrane barrel-stave pores are potential alternative therapeutics for bacterial infections and cancer. However, their optimization for clinical translation is hampered by a lack of sequence-function understanding. Recently, we have de novo designed the first synthetic barrel-stave pore-forming antimicrobial peptide with an identified function of all residues. Here, we systematically mutate the peptide to improve pore-forming ability in anticipation of enhanced activity. Using computer simulations, supported by liposome leakage and atomic force microscopy experiments, we find that pore-forming ability, while critical, is not the limiting factor for improving activity in the submicromolar range. Affinity for bacterial and cancer cell membranes needs to be optimized simultaneously. Optimized peptides more effectively killed antibiotic-resistant ESKAPEE bacteria at submicromolar concentrations, showing low cytotoxicity to human cells and skin model. Peptides showed systemic anti-infective activity in a preclinical mouse model of Acinetobacter baumannii infection. We also demonstrate peptide optimization for pH-dependent antimicrobial and anticancer activity.
Assuntos
Antineoplásicos , Desenho de Fármacos , Humanos , Antineoplásicos/farmacologia , Antineoplásicos/química , Antineoplásicos/síntese química , Animais , Camundongos , Testes de Sensibilidade Microbiana , Acinetobacter baumannii/efeitos dos fármacos , Antibacterianos/farmacologia , Antibacterianos/química , Antibacterianos/síntese química , Linhagem Celular Tumoral , Peptídeos Catiônicos Antimicrobianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/química , Peptídeos Catiônicos Antimicrobianos/síntese química , Peptídeos Antimicrobianos/química , Peptídeos Antimicrobianos/farmacologia , Peptídeos Antimicrobianos/síntese químicaRESUMO
VanRS two-component regulatory systems are key elements required for the transcriptional activation of inducible vancomycin resistance genes in bacteria, but the precise nature of the ligand signal that activates these systems has remained undefined. Using the resistance system in Streptomyces coelicolor as a model, we have undertaken a series of in vivo studies which indicate that the VanS sensor kinase in VanB-type resistance systems is activated by vancomycin in complex with the d-alanyl-d-alanine (d-Ala-d-Ala) termini of cell wall peptidoglycan (PG) precursors. Complementation of an essential d-Ala-d-Ala ligase activity by constitutive expression of vanA encoding a bifunctional d-Ala-d-Ala and d-alanyl-d-lactate (d-Ala-d-Lac) ligase activity allowed construction of strains that synthesized variable amounts of PG precursors containing d-Ala-d-Ala. Assays quantifying the expression of genes under VanRS control showed that the response to vancomycin in these strains correlated with the abundance of d-Ala-d-Ala-containing PG precursors; strains producing a lower proportion of PG precursors terminating in d-Ala-d-Ala consistently exhibited a lower response to vancomycin. Pretreatment of wild-type cells with vancomycin or teicoplanin to saturate and mask the d-Ala-d-Ala binding sites in nascent PG also blocked the transcriptional response to subsequent vancomycin exposure, and desleucyl vancomycin, a vancomycin analogue incapable of interacting with d-Ala-d-Ala residues, failed to induce van gene expression. Activation of resistance by a vancomycin-d-Ala-d-Ala PG complex predicts a limit to the proportion of PG that can be derived from precursors terminating in d-Ala-d-Lac, a restriction also enforced by the bifunctional activity of the VanA ligase.
Assuntos
Antibacterianos/farmacologia , Parede Celular/efeitos dos fármacos , Dipeptídeos/metabolismo , Peptidoglicano/metabolismo , Streptomyces coelicolor/efeitos dos fármacos , Resistência a Vancomicina/efeitos dos fármacos , Vancomicina/farmacologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Parede Celular/metabolismo , Dipeptídeos/química , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Ligases/genética , Ligases/metabolismo , Peptidoglicano/química , Streptomyces coelicolor/genética , Streptomyces coelicolor/metabolismo , Teicoplanina/farmacologia , Transcrição Gênica , Resistência a Vancomicina/genéticaRESUMO
BACKGROUND: The high overlap of mental health and substance use problems in the Canadian health care system and the subsequent demand for more effective services for clients with these high-risk issues have stimulated the debate on their integrated treatment. Although the idea of integration has been endorsed by decision makers at both programs and system levels, little attention has been paid to factors that have facilitated this process. PURPOSE: In this article, the processes by which organizational texts, language, metaphors, and symbols have facilitated institutionalization of integrated treatment are identified and discussed. METHODOLOGY/APPROACH: Findings from a qualitative case study of 2 treatment programs that were part of a large, urban hospital in Ontario providing services for populations with concurrent disorders are presented. Data were collected using semistructured interviews with professionals and clients, analysis of policy and organizational documents, and nonparticipant observations. FINDINGS: Research evidence on comorbidity, government reports, and other organizational texts that were created and disseminated across the province has contributed to the dissemination of the concept of integration. Certain ideas might be successfully implemented when environments are conducive to change; such environmental catalysts include the status of professionals who support new discourse, the characteristics and importance of the problem being addressed, and the timing of implementation. The findings clearly demonstrate that the conditions of the wider institutional environment-the emergence of research evidence on comorbidity and the provincial health care reform, with its focus on rationalizing the existing health care system-supported the idea of integration. PRACTICE IMPLICATIONS: The ability to understand how discursive activities of program planners, clinicians, and policy makers contribute to making new ideas deeply embedded in organizational structures can become an important mechanism of effective decision-making activities when health managers attempt to promote new plans and strategies.
Assuntos
Prestação Integrada de Cuidados de Saúde/organização & administração , Diagnóstico Duplo (Psiquiatria)/métodos , Difusão de Inovações , Revelação , Política Organizacional , Comorbidade , Tomada de Decisões Gerenciais , Prestação Integrada de Cuidados de Saúde/normas , Documentação/normas , Jogo de Azar/terapia , Hospitais Urbanos , Humanos , Corpo Clínico Hospitalar/educação , Corpo Clínico Hospitalar/normas , Transtornos Mentais/terapia , Ontário , Estudos de Casos Organizacionais , Avaliação de Processos e Resultados em Cuidados de Saúde/métodos , Pesquisa Qualitativa , Transtornos Relacionados ao Uso de Substâncias/terapiaRESUMO
Severe alcohol use disorder (AUD) in the context of housing instability remains one of the most complex health and social issues. Homelessness is related to increased vulnerability to stigma, marginalization and harmful ways of alcohol consumption, including non-beverage alcohol use (NBA). As a result, severe intoxication, alcohol poisoning, injury and death are common occurrences. Although harm minimization strategies have been readily proposed and examined in the context of drug use, applying the same principles to severe AUD remains controversial within the research and treatment community. This article summarizes the emerging research on managed alcohol programs to increase awareness about alcohol-related strategies that address severe AUD and provide other wrap-around supports such as housing, health and social services to mitigate various harms, including COVID-19.
RESUMO
AIM: To investigate the epidemiology of Clostridioides difficile infection (CDI) in Slovakian hospitals after the emergence of ribotype 176 (027-like) in 2016. METHODS: Between 2018 and 2019, European Centre for Disease Control and Prevention CDI surveillance protocol v2.3 was applied to 14 hospitals, with additional data collected on recent antimicrobial use and the characterization of C. difficile isolates. RESULTS: The mean hospital incidence of CDI was 4.1 cases per 10,000 patient bed-days. One hundred and five (27.6%) in-hospital deaths were reported among the 381 cases. Antimicrobial treatment within the previous 4 weeks was recorded in 90.5% (333/368) of cases. Ribotype (RT)176 was detected in 50% (n=185/370, 14 hospitals) and RT001 was detected in 34.6% (n=128/370,13/14 hospitals) of cases with RT data. Overall, 86% (n=318/370) of isolates were resistant to moxifloxacin by Thr82Ile in GyrA (99.7%). Multi-locus variable tandem repeat analysis showed clonal relatedness of predominant RTs within and between hospitals. Seven of 14 sequenced RT176 isolates and five of 13 RT001 isolates showed between zero and three allelic differences by whole-genome multi-locus sequence typing. The majority of sequenced isolates (24/27) carried the erm(B) gene and 16/27 also carried the aac(6')-aph(2'') gene with the corresponding antimicrobial susceptibility phenotypes. Nine RT176 strains carried the cfr(E)gene and one RT001 strain carried the cfr(C) gene, but without linezolid resistance. CONCLUSIONS: The newly-predominant RT176 and endemic RT001 are driving the epidemiology of CDI in Slovakia. In addition to fluoroquinolones, the use of macrolide-lincosamide-streptogramin B antibiotics can represent another driving force for the spread of these epidemic lineages. In C. difficile, linezolid resistance should be confirmed phenotypically in strains with detected cfr gene(s).
Assuntos
Clostridioides difficile , Infecções por Clostridium , Humanos , Fluoroquinolonas/farmacologia , Clostridioides difficile/genética , Ribotipagem , Eslováquia/epidemiologia , Clostridioides/genética , Linezolida , Tipagem de Sequências Multilocus , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Infecções por Clostridium/epidemiologia , Infecções por Clostridium/tratamento farmacológico , Macrolídeos , Testes de Sensibilidade MicrobianaRESUMO
Bacterial resistance to the glycopeptide antibiotic teicoplanin shows some important differences from the closely related compound vancomycin. They are currently poorly understood but may reflect significant differences in the mode of action of each antibiotic. Streptomyces coelicolor possesses a vanRSJKHAX gene cluster that when expressed confers resistance to both vancomycin and teicoplanin. The resistance to vancomycin is mediated by the enzymes encoded by vanKHAX, but not by vanJ. vanHAX effect a reprogramming of peptidoglycan biosynthesis, which is considered to be generic, conferring resistance to all glycopeptide antibiotics. Here, we show that vanKHAX are not in fact required for teicoplanin resistance in S. coelicolor, which instead is mediated solely by vanJ. vanJ is shown to encode a membrane protein oriented with its C-terminal active site exposed to the extracytoplasmic space. VanJ also confers resistance to the teicoplanin-like antibiotics ristocetin and A47934 and to a broad range of semisynthetic teicoplanin derivatives, but not generally to antibiotics or semisynthetic derivatives with vancomycin-like structures. vanJ homologues are found ubiquitously in streptomycetes and include staP from the Streptomyces toyocaensis A47934 biosynthetic gene cluster. While overexpression of staP also conferred resistance to teicoplanin, similar expression of other vanJ homologues (SCO2255, SCO7017, and SAV5946) did not. The vanJ and staP orthologues, therefore, appear to represent a subset of a larger protein family whose members have acquired specialist roles in antibiotic resistance. Future characterization of the divergent enzymatic activity within this new family will contribute to defining the molecular mechanisms important for teicoplanin activity and resistance.
Assuntos
Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Farmacorresistência Bacteriana/genética , Proteínas de Membrana/genética , Streptomyces coelicolor/genética , Teicoplanina/farmacologia , Sequência de Aminoácidos , Western Blotting , Conjugação Genética , Meios de Cultura , Escherichia coli/genética , Teste de Complementação Genética , Vetores Genéticos/genética , Glicopeptídeos/farmacologia , Testes de Sensibilidade Microbiana , Dados de Sequência Molecular , Mutação/genética , Plasmídeos , Protoplastos/metabolismo , Streptomyces coelicolor/crescimento & desenvolvimento , Relação Estrutura-Atividade , Vancomicina/farmacologiaRESUMO
BACKGROUND: A decline in the discovery of new antibacterial drugs, coupled with a persistent rise in the occurrence of drug-resistant bacteria, has highlighted antibiotics as a diminishing resource. The future development of new drugs with novel antibacterial activities requires a detailed understanding of adaptive responses to existing compounds. This study uses Streptomyces coelicolor A3(2) as a model system to determine the genome-wide transcriptional response following exposure to three antibiotics (vancomycin, moenomycin A and bacitracin) that target distinct stages of cell wall biosynthesis. RESULTS: A generalised response to all three antibiotics was identified which involves activation of transcription of the cell envelope stress sigma factor σ(E), together with elements of the stringent response, and of the heat, osmotic and oxidative stress regulons. Attenuation of this system by deletion of genes encoding the osmotic stress sigma factor σ(B) or the ppGpp synthetase RelA reduced resistance to both vancomycin and bacitracin. Many antibiotic-specific transcriptional changes were identified, representing cellular processes potentially important for tolerance to each antibiotic. Sensitivity studies using mutants constructed on the basis of the transcriptome profiling confirmed a role for several such genes in antibiotic resistance, validating the usefulness of the approach. CONCLUSIONS: Antibiotic inhibition of bacterial cell wall biosynthesis induces both common and compound-specific transcriptional responses. Both can be exploited to increase antibiotic susceptibility. Regulatory networks known to govern responses to environmental and nutritional stresses are also at the core of the common antibiotic response, and likely help cells survive until any specific resistance mechanisms are fully functional.
Assuntos
Antibacterianos/metabolismo , Antibacterianos/farmacologia , Genoma Bacteriano/genética , Streptomyces coelicolor/efeitos dos fármacos , Streptomyces coelicolor/genética , Transportadores de Cassetes de Ligação de ATP/genética , Biotina/biossíntese , Parede Celular/efeitos dos fármacos , Parede Celular/enzimologia , Parede Celular/genética , Parede Celular/metabolismo , Farmacorresistência Bacteriana/efeitos dos fármacos , Farmacorresistência Bacteriana/genética , Resposta ao Choque Térmico/efeitos dos fármacos , Resposta ao Choque Térmico/genética , Ligases/biossíntese , Pressão Osmótica/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/genética , Peptidoglicano/biossíntese , Peptidil Transferases/genética , Peptidil Transferases/metabolismo , Regulon/genética , Fator sigma/genética , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Streptomyces coelicolor/citologia , Streptomyces coelicolor/metabolismo , Transcrição Gênica/efeitos dos fármacos , Zinco/farmacologiaRESUMO
In this article we discuss the findings from a series of focus groups conducted as part of a 3-year, mixed-method evaluation of clinical programs in a large mental health and substance use treatment facility in Canada. We examined the perceptions of clinical personnel on the physical design of new treatment units and the impact on service delivery and the work environment. The new physical design appeared to support client recovery and reduce stigma; however, it brought certain challenges. Participants reported a compromised ability to monitor clients, a lack of designated therapeutic spaces, and insufficient workspace for staff. They also thought that physical design positively facilitated communication and therapeutic relationships among clinicians and clients, and increased team cohesion. We suggest that, from these findings, new avenues for research on achieving the important balance between client and staff needs in health facility design can be explored.
Assuntos
Pessoal de Saúde/psicologia , Serviços de Saúde Mental/organização & administração , Assistência Centrada no Paciente/métodos , Instituições Residenciais/organização & administração , Meio Social , Transtornos Relacionados ao Uso de Substâncias/psicologia , Atitude do Pessoal de Saúde , Planejamento Ambiental , Grupos Focais , Planejamento de Instituições de Saúde , Humanos , Saúde Mental , Ontário , Assistência Centrada no Paciente/organização & administração , Avaliação de Programas e Projetos de Saúde , Instituições Residenciais/métodos , Percepção Social , Transtornos Relacionados ao Uso de Substâncias/tratamento farmacológico , Transtornos Relacionados ao Uso de Substâncias/terapia , Recursos Humanos , Local de Trabalho/psicologiaRESUMO
The increase in antibiotic resistance among Gram-positive bacteria underscores the urgent need to develop new antibiotics. New antibiotics should target actively growing susceptible bacteria that are resistant to clinically accepted antibiotics including bacteria that are not growing or are protected in a biofilm environment. In this paper, we compare the in vitro activities of two new semisynthetic glycopeptide antibiotics, MA79 and ERJ390, with two clinically used glycopeptide antibiotics-vancomycin and teicoplanin. The new antibiotics effectively killed not only exponentially growing cells of Staphylococcus aureus, but also cells in the stationary growth phase and biofilm.
RESUMO
In natural environments, antibiotics are important means of interspecies competition. At subinhibitory concentrations, they act as cues or signals inducing antibiotic production; however, our knowledge of well-documented antibiotic-based sensing systems is limited. Here, for the soil actinobacterium Streptomyces lincolnensis, we describe a fundamentally new ribosome-mediated signaling cascade that accelerates the onset of lincomycin production in response to an external ribosome-targeting antibiotic to synchronize antibiotic production within the population. The entire cascade is encoded in the lincomycin biosynthetic gene cluster (BGC) and consists of three lincomycin resistance proteins in addition to the transcriptional regulator LmbU: a lincomycin transporter (LmrA), a 23S rRNA methyltransferase (LmrB), both of which confer high resistance, and an ATP-binding cassette family F (ABCF) ATPase, LmrC, which confers only moderate resistance but is essential for antibiotic-induced signal transduction. Specifically, antibiotic sensing occurs via ribosome-mediated attenuation, which activates LmrC production in response to lincosamide, streptogramin A, or pleuromutilin antibiotics. Then, ATPase activity of the ribosome-associated LmrC triggers the transcription of lmbU and consequently the expression of lincomycin BGC. Finally, the production of LmrC is downregulated by LmrA and LmrB, which reduces the amount of ribosome-bound antibiotic and thus fine-tunes the cascade. We propose that analogous ABCF-mediated signaling systems are relatively common because many ribosome-targeting antibiotic BGCs encode an ABCF protein accompanied by additional resistance protein(s) and transcriptional regulators. Moreover, we revealed that three of the eight coproduced ABCF proteins of S. lincolnensis are clindamycin responsive, suggesting that the ABCF-mediated antibiotic signaling may be a widely utilized tool for chemical communication. IMPORTANCE Resistance proteins are perceived as mechanisms protecting bacteria from the inhibitory effect of their produced antibiotics or antibiotics from competitors. Here, we report that antibiotic resistance proteins regulate lincomycin biosynthesis in response to subinhibitory concentrations of antibiotics. In particular, we show the dual character of the ABCF ATPase LmrC, which confers antibiotic resistance and simultaneously transduces a signal from ribosome-bound antibiotics to gene expression, where the 5' untranslated sequence upstream of its encoding gene functions as a primary antibiotic sensor. ABCF-mediated antibiotic signaling can in principle function not only in the induction of antibiotic biosynthesis but also in selective gene expression in response to any small molecules targeting the 50S ribosomal subunit, including clinically important antibiotics, to mediate intercellular antibiotic signaling and stress response induction. Moreover, the resistance-regulatory function of LmrC presented here for the first time unifies functionally inconsistent ABCF family members involving antibiotic resistance proteins and translational regulators.
Assuntos
Adenosina Trifosfatases/metabolismo , Antibacterianos/biossíntese , Antibacterianos/farmacologia , Lincomicina/biossíntese , Lincomicina/farmacologia , Proteínas Associadas à Resistência a Múltiplos Medicamentos/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Farmacorresistência Bacteriana , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Metiltransferases , Proteínas Associadas à Resistência a Múltiplos Medicamentos/genética , Família Multigênica , Ribossomos/metabolismo , Transdução de Sinais , Streptomyces/metabolismo , Fatores de TranscriçãoRESUMO
The dysbiosis of oral microbiome (OM) precedes the clinical signs of periodontal disease. Its simple measure thus could indicate individuals at risk of periodontitis development; however, such a tool is still missing. Up to now, numerous microbial taxa were associated with periodontal health or periodontitis. The outputs of most studies could, nevertheless, be slightly biased from following two reasons: First, the healthy group is often characterized only by the absence of the disease, but the individuals could already suffer from dysbiosis without any visible signs. Second, the healthy/diseased OM characteristics are frequently determined based on average data obtained for whole groups of periodontally healthy persons versus patients. Especially in smaller sets of tested individuals the typical individual variability can thus complicate the unambiguous assignment of oral taxa to respective state of health. In this work the taxonomic composition of OM was evaluated for 20 periodontally healthy individuals and 15 patients with chronic periodontitis. The narrowed selection set of the most diseased patients (confirmed by clinical parameters) and the most distant group of healthy individuals with the lowest probability of dysbiosis was determined by clustering analysis and used for identification of marker taxa. Based on their representation in each individual oral cavity we proposed the numeric index of periodontal health called R/G value. Its diagnostic potential was further confirmed using independent set of 20 periodontally healthy individuals and 20 patients with periodontitis with 95 percent of samples assigned correctly. We also assessed the individual temporal OM dynamics in periodontal health and we compared it to periodontitis. We revealed that the taxonomic composition of the system changes dynamically but generally it ranges within values typical for periodontal health or transient state, but far from values typical for periodontitis. R/G value tool, formulated from individually evaluated data, allowed us to arrange individual OMs into a continuous series, instead of two distinct groups, thus mimicking the gradual transformation of a virtual person from periodontal health to disease. The application of R/G value index thus represents a very promising diagnostic tool for early prediction of persons at risk of developing periodontal disease.
Assuntos
Periodontite Crônica , Microbiota , Disbiose , HumanosRESUMO
vanZ, a member of the VanA glycopeptide resistance gene cluster, confers resistance to lipoglycopeptide antibiotics independent of cell wall precursor modification by the vanHAX genes. Orthologs of vanZ are present in the genomes of many clinically relevant bacteria, including Enterococcus faecium and Streptococcus pneumoniae; however, vanZ genes are absent in Staphylococcus aureus. Here, we show that the expression of enterococcal vanZ paralogs in S. aureus increases the minimal inhibitory concentrations of lipoglycopeptide antibiotics teicoplanin, dalbavancin, oritavancin and new teicoplanin pseudoaglycone derivatives. The reduction in the binding of fluorescently labeled teicoplanin to the cells suggests the mechanism of VanZ-mediated resistance. In addition, using a genomic vanZ gene knockout mutant of S. pneumoniae, we have shown that the ability of VanZ proteins to compromise the activity of lipoglycopeptide antibiotics by reducing their binding is a more general feature of VanZ-superfamily proteins.
RESUMO
OBJECTIVES: The aim of this study was to analyse the DNA sequences of three teicoplanin-resistant Staphylococcus epidermidis isolates collected from patients not previously treated with glycopeptide antibiotics. METHODS: The minimum inhibitory concentrations (MICs) of 12 antibiotics, including teicoplanin and vancomycin, were determined by the broth microdilution method. Genomic DNA was isolated, was sequenced by HiSeqX paired-end sequencing and was assembled into draft genome sequences using MyPro pipeline. RESULTS: Analysis of the draft genome sequences demonstrated that the teicoplanin-resistant S. epidermidis isolates belonged to multilocus sequence typing (MLST) sequence types ST5 and ST87 and encoded multiple antimicrobial resistance genes, including the methicillin resistance gene mecA. CONCLUSIONS: This report highlights the risk of dissemination of S. epidermidis strains resistant to a wide range of clinically important antibiotics.