RESUMO
In recent years, increasing resistance of Bacteroides fragilis to several antibiotics has been reported in different countries. The aim of this study was to evaluate the antibiotic resistance profiles of Bacteroides spp. isolated from clinical samples by phenotypic and molecular methods. A total of 40 nonrepetitive isolates of the B. fragilis group were studied from 2018 to 2019. The species was identified by API 20A system. The minimum inhibitory concentrations (MICs) were determined by Sensititre anaerobe MIC plate. The presence of the nim and cfiA genes was checked by conventional PCR. The association between genes and insertion sequence (IS) was performed by whole genome sequencing. Eleven isolates were categorized as metronidazole-resistant and only 2 isolates harbored the nim gene. Five isolates were imipenem-resistant, but cfiA gene was detected in two isolates. cfiA gene was closely related to the cfiA-4 allele and associated with IS614B. The nim gene was not related to any nim gene type and was considered a new variant named nimL. IS612 was found upstream of nimL gene. In view of the scarcity of data on B. fragilis, there is a need to surveil antibiotic resistance levels and molecular mechanisms to implement better antimicrobial therapies against this important group of bacteria.
Assuntos
Antibacterianos , Infecções por Bacteroides , Humanos , Antibacterianos/farmacologia , Bacteroides , Bacteroides fragilis/genética , Equador , beta-Lactamases/genética , Infecções por Bacteroides/tratamento farmacológico , Infecções por Bacteroides/microbiologia , Testes de Sensibilidade Microbiana , Farmacorresistência Bacteriana/genética , Proteínas de Bactérias/genéticaRESUMO
Intestinal barrier is essential for dietary products and microbiota compartmentalization and therefore gut homeostasis. When this barrier is broken, cecal content overflows into the peritoneal cavity, leading to local and systemic robust inflammatory response, characterizing peritonitis and sepsis. It has been shown that IL-1ß contributes with inflammatory storm during peritonitis and sepsis and its inhibition has beneficial effects to the host. Therefore, we investigated the mechanisms underlying IL-1ß secretion using a widely adopted murine model of experimental peritonitis. The combined injection of sterile cecal content (SCC) and the gut commensal bacteria Bacteroides fragilis leads to IL-1ß-dependent peritonitis, which was mitigated in mice deficient in NLRP3 (nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-3) inflammasome components. Typically acting as a damage signal, SCC, but not B. fragilis, activates canonical pathway of NLRP3 promoting IL-1ß secretion in vitro and in vivo. Strikingly, absence of fiber in the SCC drastically reduces IL-1ß production, whereas high-fiber SCC conversely increases this response in an NLRP3-dependent manner. In addition, NLRP3 was also required for IL-1ß production induced by purified dietary fiber in primed macrophages. Extending to the in vivo context, IL-1ß-dependent peritonitis was worsened in mice injected with B. fragilis and high-fiber SCC, whereas zero-fiber SCC ameliorates the pathology. Corroborating with the proinflammatory role of dietary fiber, IL-1R-deficient mice were protected from peritonitis induced by B. fragilis and particulate bran. Overall, our study highlights a function, previously unknown, for dietary fibers in fueling peritonitis through NLRP3 activation and IL-1ß secretion outside the gut.
Assuntos
Infecções por Bacteroides/imunologia , Bacteroides fragilis/imunologia , Fibras na Dieta/efeitos adversos , Inflamassomos/metabolismo , Interleucina-1beta/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/deficiência , Peritonite/imunologia , Animais , Infecções por Bacteroides/microbiologia , Dieta , Fibras na Dieta/administração & dosagem , Modelos Animais de Doenças , Macrófagos/imunologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteína 3 que Contém Domínio de Pirina da Família NLR/genética , Peritonite/microbiologia , Receptores de Interleucina-1/deficiência , Receptores de Interleucina-1/genética , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/imunologiaRESUMO
PURPOSE: To evaluate the response of aging rats with sepsis to two different antibiotic regimens. METHODS: The study was conducted with 30 aging rats (18 month-old) with autologous feces peritonitis. The animals were divided into three groups: Group 0 received no therapeutic intervention (control), while Group 1 received a single dose of 40 mg/kg meropenem and Group 2 received a single dose of 20 mg/kg moxifloxacin. The intervention in both Groups was made 6 hours after induction of peritonitis. The animals were followed up to 15 days for evaluating morbidity and mortality. The weights at baseline were similar in all groups. RESULTS: At the end of follow-up, weight loss was significantly greater (p=0.0045) in Group 0 (non-intervention controls). Culture from a blood sample at the end of follow-up was positive in all the animals in Group 0, in two animals in Group 1 and in four animals in Group 2. Morbidity/mortality was significantly higher in Group 0 compared to both Groups 1 and 2 (p=0.003) but the scores were not significantly different between Groups 1 and 2 (p=0.6967). CONCLUSION: Both antibiotic regimens rendered promising results for the treatment of fecal peritonitis.
Assuntos
Envelhecimento , Antibacterianos/uso terapêutico , Infecções por Bacteroides/complicações , Peritonite/tratamento farmacológico , Animais , Modelos Animais de Doenças , Fezes , Masculino , Peritonite/microbiologia , Ratos , Ratos Wistar , Sepse/tratamento farmacológicoRESUMO
Abstract Purpose: To evaluate the response of aging rats with sepsis to two different antibiotic regimens. Methods: The study was conducted with 30 aging rats (18 month-old) with autologous feces peritonitis. The animals were divided into three groups: Group 0 received no therapeutic intervention (control), while Group 1 received a single dose of 40 mg/kg meropenem and Group 2 received a single dose of 20 mg/kg moxifloxacin. The intervention in both Groups was made 6 hours after induction of peritonitis. The animals were followed up to 15 days for evaluating morbidity and mortality. The weights at baseline were similar in all groups. Results: At the end of follow-up, weight loss was significantly greater (p=0.0045) in Group 0 (non-intervention controls). Culture from a blood sample at the end of follow-up was positive in all the animals in Group 0, in two animals in Group 1 and in four animals in Group 2. Morbidity/mortality was significantly higher in Group 0 compared to both Groups 1 and 2 (p=0.003) but the scores were not significantly different between Groups 1 and 2 (p=0.6967). Conclusion: Both antibiotic regimens rendered promising results for the treatment of fecal peritonitis.
Assuntos
Animais , Masculino , Ratos , Peritonite/tratamento farmacológico , Infecções por Bacteroides/complicações , Envelhecimento , Antibacterianos/uso terapêutico , Peritonite/microbiologia , Ratos Wistar , Sepse/tratamento farmacológico , Modelos Animais de Doenças , FezesRESUMO
ABSTRACT Bacteroides fragilis is the strict anaerobic bacteria most commonly found in human infections, and has a high mortality rate. Among other virulence factors, the remarkable ability to acquire resistance to a variety of antimicrobial agents and to tolerate nanomolar concentrations of oxygen explains in part their success in causing infection and colonizing the mucosa. Much attention has been given to genes related to multiple drug resistance derived from plasmids, integrons or transposon, but such genes are also detected in chromosomal systems, like the mar (multiple antibiotic resistance) locus, that confer resistance to a range of drugs. Regulators like MarR, that control expression of the locus mar, also regulate resistance to organic solvents, disinfectants and oxygen reactive species are important players in these events. Strains derived from the parental strain 638R, with mutations in the genes hereby known as marRI (BF638R_3159) and marRII (BF638R_3706) were constructed by gene disruption using a suicide plasmid. Phenotypic response of the mutant strains to hydrogen peroxide, cell survival assay against exposure to oxygen, biofilm formation, resistance to bile salts and resistance to antibiotics was evaluated. The results showed that the mutant strains exhibit statistically significant differences in their response to oxygen stress, but no changes were observed in survival when exposed to bile salts. Biofilm formation was not affected by either gene disruption. Both mutant strains however, became more sensitive to multiple antimicrobial drugs tested. This indicates that as observed in other bacterial species, MarR are an important resistance mechanism in B. fragilis.
Assuntos
Humanos , Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Bacteroides fragilis/efeitos dos fármacos , Bacteroides fragilis/genética , Infecções por Bacteroides/microbiologia , Proteínas Repressoras/genética , Proteínas de Bactérias/metabolismo , Bacteroides fragilis/isolamento & purificação , Bacteroides fragilis/metabolismo , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Inativação Gênica , Testes de Sensibilidade Microbiana , Proteínas Repressoras/metabolismoRESUMO
Bacteroides fragilis is the strict anaerobic bacteria most commonly found in human infections, and has a high mortality rate. Among other virulence factors, the remarkable ability to acquire resistance to a variety of antimicrobial agents and to tolerate nanomolar concentrations of oxygen explains in part their success in causing infection and colonizing the mucosa. Much attention has been given to genes related to multiple drug resistance derived from plasmids, integrons or transposon, but such genes are also detected in chromosomal systems, like the mar (multiple antibiotic resistance) locus, that confer resistance to a range of drugs. Regulators like MarR, that control expression of the locus mar, also regulate resistance to organic solvents, disinfectants and oxygen reactive species are important players in these events. Strains derived from the parental strain 638R, with mutations in the genes hereby known as marRI (BF638R_3159) and marRII (BF638R_3706) were constructed by gene disruption using a suicide plasmid. Phenotypic response of the mutant strains to hydrogen peroxide, cell survival assay against exposure to oxygen, biofilm formation, resistance to bile salts and resistance to antibiotics was evaluated. The results showed that the mutant strains exhibit statistically significant differences in their response to oxygen stress, but no changes were observed in survival when exposed to bile salts. Biofilm formation was not affected by either gene disruption. Both mutant strains however, became more sensitive to multiple antimicrobial drugs tested. This indicates that as observed in other bacterial species, MarR are an important resistance mechanism in B. fragilis.
Assuntos
Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Infecções por Bacteroides/microbiologia , Bacteroides fragilis/efeitos dos fármacos , Bacteroides fragilis/genética , Proteínas Repressoras/genética , Proteínas de Bactérias/metabolismo , Bacteroides fragilis/isolamento & purificação , Bacteroides fragilis/metabolismo , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Inativação Gênica , Humanos , Testes de Sensibilidade Microbiana , Proteínas Repressoras/metabolismoRESUMO
CfiA (CcrA) metallo-ß-lactamase is the main carbapenem resistance mechanism in B. fragilis. From cfiA positive isolates detected in a previous surveillance study, 3 displayed resistance to imipenem while the remaining were susceptible. The aim of this study was to identify the cfiA alleles and to analyze the presence of IS elements in their upstream regions. CfiA-1, CfiA-4, CfiA-13, CfiA-19 and CfiA-22 were detected. IS elements belonging to IS21 family and IS942 group were identified upstream to cfiA in the 3 imipenem resistant isolates. We present an exhaustive analysis of cfiA/CfiA registers in databases, illustrating the inconsistencies in both organization and nomenclature. According to this analysis CfiA family comprises nowadays 15 different CfiA variants coded by 24 cfiA sequences. Curation of CfiA database is mandatory, if not new cfiA admission at GenBank will contribute to make this classification more complex.
Assuntos
Proteínas de Bactérias/genética , Infecções por Bacteroides/microbiologia , Bacteroides fragilis/classificação , Bacteroides fragilis/genética , Fases de Leitura Aberta , beta-Lactamases/genética , Alelos , Antibacterianos/farmacologia , Argentina/epidemiologia , Infecções por Bacteroides/epidemiologia , Bacteroides fragilis/efeitos dos fármacos , Bacteroides fragilis/isolamento & purificação , Humanos , Testes de Sensibilidade Microbiana , Filogenia , Vigilância em Saúde PúblicaRESUMO
Enterotoxigenic Bacteroides fragilis (ETBF) is an important part of the human and animal intestinal microbiota and is commonly associated with diarrhea. ETBF strains produce an enterotoxin encoded by the bft gene located in the B. fragilis pathogenicity island (BfPAI). Non-enterotoxigenic B. fragilis (NTBF) strains lack the BfPAI and usually show two different genetic patterns, II and III, based on the absence or presence of a BfPAI-flanking region, respectively. The incidence of ETBF and NTBF strains in fecal samples isolated from children without acute diarrhea or any other intestinal disorders was determined. All 84 fecal samples evaluated were B. fragilis-positive by PCR, four of them harbored the bft gene, 27 contained the NTBF pattern III DNA sequence, and 52 were considered to be NTBF pattern II samples. One sample was positive for both ETBF and NTBF pattern III DNA sequences. All 19 B. fragilis strains isolated by the culture method were bft-negative, 9 belonged to pattern III and 10 to pattern II. We present an updated overview of the ETBF and NTBF incidence in the fecal microbiota of children from Sao Paulo City, Brazil.
Assuntos
Toxinas Bacterianas/genética , Infecções por Bacteroides/microbiologia , Bacteroides fragilis/genética , Bacteroides fragilis/isolamento & purificação , Fezes/microbiologia , Genótipo , Metaloendopeptidases/genética , Animais , Infecções por Bacteroides/epidemiologia , Bacteroides fragilis/classificação , Brasil/epidemiologia , Criança , Pré-Escolar , DNA Bacteriano/genética , Feminino , Humanos , Incidência , Masculino , Tipagem Molecular , Reação em Cadeia da PolimeraseRESUMO
Enterotoxigenic Bacteroides fragilis (ETBF) is an important part of the human and animal intestinal microbiota and is commonly associated with diarrhea. ETBF strains produce an enterotoxin encoded by the bft gene located in the B. fragilis pathogenicity island (BfPAI). Non-enterotoxigenic B. fragilis (NTBF) strains lack the BfPAI and usually show two different genetic patterns, II and III, based on the absence or presence of a BfPAI-flanking region, respectively. The incidence of ETBF and NTBF strains in fecal samples isolated from children without acute diarrhea or any other intestinal disorders was determined. All 84 fecal samples evaluated were B. fragilis-positive by PCR, four of them harbored the bft gene, 27 contained the NTBF pattern III DNA sequence, and 52 were considered to be NTBF pattern II samples. One sample was positive for both ETBF and NTBF pattern III DNA sequences. All 19 B. fragilis strains isolated by the culture method were bft-negative, 9 belonged to pattern III and 10 to pattern II. We present an updated overview of the ETBF and NTBF incidence in the fecal microbiota of children from Sao Paulo City, Brazil.
Assuntos
Animais , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Toxinas Bacterianas/genética , Infecções por Bacteroides/microbiologia , Bacteroides fragilis/genética , Bacteroides fragilis/isolamento & purificação , Fezes/microbiologia , Genótipo , Metaloendopeptidases/genética , Infecções por Bacteroides/epidemiologia , Bacteroides fragilis/classificação , Brasil/epidemiologia , DNA Bacteriano/genética , Incidência , Tipagem Molecular , Reação em Cadeia da PolimeraseRESUMO
BACKGROUND: Pylephlebitis or septic thrombophlebitis of the portal venous system is a rare but serious complication of intra-abdominal infections which drain into the portal venous system. Its diagnosis is based on clinical suspicion and imaging tests, mainly a computed tomography scan, given the lack of specificity of the signs and symptoms. Spread of septic emboli is the major cause of morbidity and mortality. The aim of the study was to analyse patients diagnosed in our hospital. MATERIAL AND METHODS: Retrospective descriptive study of patients diagnosed with pylephlebitis in our hospital. CLINICAL CASES: Four patients were included, 3 men and one woman. In 3 cases it was acute cholecystitis that led to the diagnosis of pylephlebitis at the same time as the intra-abdominal infection. Emergency surgery was performed in one case, whilst the other 2 were treated conservatively. Blood cultures were performed in all cases, and empirical antibiotic treatment was used. In the only case of acute appendicitis, diagnosis of pylephlebitis was achieved during the study of postoperative fever, with empirical antibiotic treatment also being started. The haematologist was requested to start the required anticoagulation therapy in all cases. CONCLUSIONS: Pylephlebitis is a rare complication of intra-abdominal infections that may make lead to a worse outcome. A high level of suspicion is required as well as imaging tests to make an early diagnosis and appropriate treatment.
Assuntos
Apendicite/complicações , Infecções por Bacteroides/complicações , Colecistite/complicações , Embolia/etiologia , Infecções por Bactérias Gram-Positivas/complicações , Infecções por Klebsiella/complicações , Veia Porta , Tromboflebite/etiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Antibacterianos/uso terapêutico , Anticoagulantes/uso terapêutico , Apendicectomia , Bacteriemia/etiologia , Infecções por Bacteroides/tratamento farmacológico , Infecções por Bacteroides/cirurgia , Colecistectomia , Colecistite/cirurgia , Coinfecção , Terapia Combinada , Emergências , Enterococcus faecium/isolamento & purificação , Feminino , Infecções por Bactérias Gram-Positivas/tratamento farmacológico , Infecções por Bactérias Gram-Positivas/cirurgia , Humanos , Infecções por Klebsiella/tratamento farmacológico , Infecções por Klebsiella/cirurgia , Klebsiella oxytoca/isolamento & purificação , Klebsiella pneumoniae/isolamento & purificação , Fígado/irrigação sanguínea , Fígado/patologia , Masculino , Pessoa de Meia-Idade , Veia Porta/diagnóstico por imagem , Veia Porta/microbiologia , Estudos Retrospectivos , Tromboflebite/diagnóstico por imagem , Tromboflebite/tratamento farmacológico , Tromboflebite/microbiologia , Tomografia Computadorizada por Raios XRESUMO
INTRODUCTION: Metronidazole is the antibiotic of choice for the management of infections caused by anaerobes. Its administration requires multiple daily doses causing increased medication errors. Due to its high post-antibiotic effect and rapid concentration-dependent bactericidal activity, administration of this antibiotic in an extended dosing interval would achieve PK/PD parameters effectively. OBJECTIVE: To assess the probability of achieving effective PK/PD relationship with the administration of 1,000 mg every 24 hours of metronidazole for Bacteroides fragilis infections. METHODS: A clinical trial was conducted in a group of volunteers who received a single oral dose of 500 or 1,000 mg of metronidazole. Determinations of values of Cmax, t max, and AUCC0-24 h. determined using the trapezoidal method, were obtained for a Markov simulation that would allow for determining the likelihood of achieving a AUC0-24 h/MIC ratio above 70 for infections caused by susceptible B. fragilis. RESULTS: Cmax (24,03 ± 6,89 mg/L) and t max (1,20 ± 0.80 hrs) and the value of AUC0-24 h (241.91 ± 48.14 mg * h/L) were determined. The probability of obtaining a AUC0-24 h/MIC ratio greater than 70 was greater than 99%. CONCLUSION: From a pharmacokinetic perspective, with the administration of a daily dose of 1,000 mg of metronidazole, it is possible to achieve a therapeutic goal of AUC0-24 h/MIC ratio above 70 for the treatment of anaerobic infections.
Assuntos
Antibacterianos/farmacocinética , Infecções por Bacteroides/tratamento farmacológico , Infecções por Bacteroides/metabolismo , Bacteroides fragilis , Metronidazol/farmacocinética , Administração Oral , Adolescente , Adulto , Antibacterianos/administração & dosagem , Esquema de Medicação , Feminino , Humanos , Masculino , Cadeias de Markov , Metronidazol/administração & dosagem , Pessoa de Meia-Idade , Adulto JovemRESUMO
Introduction: Metronidazole is the antibiotic of choice for the management of infections caused by anaerobes. Its administration requires multiple daily doses causing increased medication errors. Due to its high post-antibiotic effect and rapid concentration-dependent bactericidal activity, administration of this antibiotic in an extended dosing interval would achieve PK/PD parameters effectively. Objective: To assess the probability of achieving effective PK/PD relationship with the administration of 1,000 mg every 24 hours of metronidazole for Bacteroides fragilis infections. Methods: A clinical trial was conducted in a group of volunteers who received a single oral dose of 500 or 1,000 mg of metronidazole. Determinations of values of Cmax, t max, and AUCC0-24 h. determined using the trapezoidal method, were obtained for a Markov simulation that would allow for determining the likelihood of achieving a AUC0-24 h/MIC ratio above 70 for infections caused by susceptible B. fragilis. Results: Cmax (24,03 ± 6,89 mg/L) and t max (1,20 ± 0.80 hrs) and the value of AUC0-24 h (241.91 ± 48.14 mg * h/L) were determined. The probability of obtaining a AUC0-24 h/MIC ratio greater than 70 was greater than 99%. Conclusion: From a pharmacokinetic perspective, with the administration of a daily dose of 1,000 mg of metronidazole, it is possible to achieve a therapeutic goal of AUC0-24 h/MIC ratio above 70 for the treatment of anaerobic infections.
Introducción: Metronidazol es el antimicrobiano de elección para el manejo de infecciones anaeróbicas. Su administración requiere de dosis múltiples provocando aumento en errores medicamentosos. Debido al efecto post-antibiótico y a la actividad bactericida concentración-dependiente, la administración de metronidazol en intervalos ampliados de administración permitiría alcanzar parámetros PK/PD efectivos. Objetivo: Evaluar la probabilidad de alcanzar una relación PK/PD efectiva con la administración de 1.000 mg cada 24 h de metronidazol para infecciones por Bacteroides fragilis. Método: Se realizó un ensayo clínico sobre un grupo de voluntarios a quienes se les administró una monodosis oral de 500 y 1.000 mg de metronidazol, respectivamente. Se establecieron parámetros farmacocinéticos empleando el método trapezoidal. Se realizó una simulación de Markov que permitiera establecer la probabilidad de alcanzar una relación AUC0-24 h/CIM > 70 en infecciones por B. fragilis. Resultados: Se determinaron los valores de Cmax (24,03 ± 6,89 mg/L), t max (1,20± 0,8h) y AUC0-24 h (241,91 ± 48,14 mg*h/L), con lo cual la probabilidad de alcanzar una relación AUC0-24 h/CIM > 70 con 1.000 mg de metronidazol fue superior a 99%. Conclusión: Con la administración de 1.000 mg cada 24 h sería posible alcanzar una relación PK/PD efectiva para el tratamiento de infecciones anaeróbicas.
Assuntos
Humanos , Masculino , Feminino , Adolescente , Adulto , Pessoa de Meia-Idade , Adulto Jovem , Antibacterianos/farmacocinética , Infecções por Bacteroides/tratamento farmacológico , Infecções por Bacteroides/metabolismo , Bacteroides fragilis , Metronidazol/farmacocinética , Administração Oral , Antibacterianos/administração & dosagem , Esquema de Medicação , Cadeias de Markov , Metronidazol/administração & dosagemRESUMO
As antimicrobials are introduced into the environment, microorganisms may respond in different ways, sometimes displaying alterations in cellular physiology. Considering the clinical relevance of the Bacteroides fragilis, strains were selected to investigate bacterial response after exposure to subinhibitory concentrations (SIC) of ampicillin (AMP), ampicillin-sulbactam (AMS), clindamycin (CLI), chloramphenicol (CHL), and its relationship to a host model (BALB/c mice) after experimental challenge. Morphological alterations, and biochemical-physiological and genetic profiles were evaluated among drug-selected bacteria. Histopathological evaluation of the liver and spleen, and inflammatory cytokines were determined after bacterial infection in mice. AMP and AMS exposure were related to most significant cellular alterations. Decreased sensitivity to all antimicrobials was observed for all drug-selected bacteria. Down regulation in adherence properties were also observed. Spleen and liver alterations were observed in different patterns. Increased levels of TNF-α, IL-6 and IFN-γ were also observed. Our results show that SICs of AMP, AMS, CLI and CHL may be related to alterations in cell physiology in B. fragilis with implications to the host-bacteria relationship. The data emphasizes the risks of inappropriate chemotherapy, and the concerns regarding ecological consequences lead by SICs of antimicrobials in resident microbiota.
Assuntos
Antibacterianos/farmacologia , Infecções por Bacteroides/microbiologia , Bacteroides fragilis/efeitos dos fármacos , Bacteroides fragilis/crescimento & desenvolvimento , Animais , Infecções por Bacteroides/genética , Infecções por Bacteroides/metabolismo , Bacteroides fragilis/patogenicidade , Feminino , Humanos , Interferon gama/genética , Interferon gama/metabolismo , Interleucina-6/genética , Interleucina-6/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Testes de Sensibilidade Microbiana , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/metabolismo , Virulência/efeitos dos fármacosRESUMO
Multidrug resistance in Bacteroides spp. and related genera is uncommon and has not been described in Latin America until now. We studied phenotypically and genotypically the multidrug resistance of 10 clinical strains of Bacteroides, two of Parabacteroides distasonis, and one of Pseudoflavonifractor capillosus recovered in a national hospital between 2006 and 2010. To this end, we determined minimum inhibitory concentrations (MICs) of amoxicillin, amoxicillin-clavulanic acid, cefotaxime, imipenem, clindamycin, ciprofloxacin, tetracycline, and metronidazole using E-tests, evaluated the isolates for ß-lactamases with nitrocefin hydrolysis tests, performed a polymerase chain reaction (PCR)-based screening of erm, tet, and nim genes, obtained partial gyrA sequences, and studied the effect of tazobactam and efflux pump inhibitors (EPI) on the MIC of cefotaxime, clindamycin, and ciprofloxacin. Three isolates were resistant to four different classes of antibiotics and 10 were resistant to three. ß-lactam resistance was in most cases due to ß-lactamases susceptible of partial inhibition by tazobactam. Ten isolates were cfxA-positive and two isolates had cepA. Twelve isolates were highly resistant to clindamycin and nine were highly resistant to ciprofloxacin. However, these phenotypes were not linked to ermA, ermB, ermF, and ermG or mutations in gyrA. Addition of EPI lowered the MICs of clindamycin and ciprofloxacin of one and four isolates, respectively. Twelve isolates had tetQ and four were positive for tetM. In both cases, genes of the two-component system RteAB accompanied tet genes. Although metronidazole susceptibility was universal, nim genes were not present. To our knowledge, this is the first report of multidrug resistance due to less commonly identified or alternative mechanisms in strains of Bacteroides and related species from a developing country.
Assuntos
Antibacterianos/farmacologia , Infecções por Bacteroides/epidemiologia , Bacteroides/genética , Infecções por Clostridium/epidemiologia , Clostridium/genética , Genes Bacterianos , Bacteroides/efeitos dos fármacos , Bacteroides/enzimologia , Bacteroides/isolamento & purificação , Infecções por Bacteroides/tratamento farmacológico , Infecções por Bacteroides/microbiologia , Clindamicina/farmacologia , Clostridium/efeitos dos fármacos , Clostridium/enzimologia , Clostridium/isolamento & purificação , Infecções por Clostridium/tratamento farmacológico , Infecções por Clostridium/microbiologia , Costa Rica/epidemiologia , Farmacorresistência Bacteriana Múltipla , Genótipo , Humanos , Metronidazol/farmacologia , Mutação , Fenótipo , beta-Lactamases/genética , beta-Lactamases/metabolismo , beta-Lactamas/farmacologiaRESUMO
The frequency of finding of clindamycin-resistant anaerobic bacteria in clinical samples has doubled from 2008 to 2010 in Costa Rica. To determine whether this increase is due to dissemination of erm genes aided by tetQ elements, we analyzed 100 isolates of Bacteroides or Parabacteroides from a regional hospital, a national hospital, and the community. Antimicrobial susceptibilities were recorded with a broth micro-dilution method and erm genes were detected by PCR and Southern blotting. In addition, plasmid isolation and mating experiments were performed to clarify the location and mobility of the detected erm genes. Resistance to clindamycin was by far more frequent in the regional hospital (72%) than in the national hospital (29%) and the community (26%). Resistance to tetracycline was even more common, with the community (85%) outweighing the hospitals (71-72%). While MIC of clindamycin were higher in the hospitals than in the community (P < 0.05), the opposite was seen for tetracycline (P < 0.0001). Of the sought-after genes, only ermG (n = 2), ermA (n = 1), and ermF (n = 1) were detected in the hospitals and ermF in the community (n = 2). In opposition to the low frequency of finding of erm genes, 71% of the isolates were positive for tetQ. None of the detected genes were encoded on plasmids. Only three isolates from the hospitals transferred their erm genes laterally. By contrast, 13 hospital isolates and two community isolates transferred tetQ. Despite the widespread finding of tetracycline-resistant tetQ-positive bacteria, mobile erm genes were rare in our bacterial collection. We conclude that the detected erm genes are likely not included in typical conjugative transposons of Bacteroides and Parabacteroides.
Assuntos
Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Infecções por Bacteroides/microbiologia , Bacteroides/genética , Bacteroides/efeitos dos fármacos , Bacteroides/isolamento & purificação , Infecções por Bacteroides/epidemiologia , Clindamicina/farmacologia , Conjugação Genética , Costa Rica/epidemiologia , DNA Bacteriano/genética , Farmacorresistência Bacteriana Múltipla , Fezes/microbiologia , Humanos , Metiltransferases/genética , Testes de Sensibilidade Microbiana , Fenótipo , Plasmídeos/genética , Reação em Cadeia da Polimerase , Tetraciclina/farmacologia , Resistência a Tetraciclina/genéticaRESUMO
OBJECTIVES: This study tested the hypotheses that there is: (1) higher bacterial frequency in peri-implantitis/periodontitis, followed by mucositis/gingivitis and peri-implant/periodontal health; (2) similar bacterial frequency between comparable peri-implant and periodontal clinical statuses. DESIGN OF STUDY: The presence of Porphyromonas gingivalis, Tannerella forsythia, Campylobacter rectus, Prevotella intermedia, Treponema denticola and Aggregatibacter actinomycetemcomitans was evaluated in peri-implant (n=53) and periodontal (n=53) health; mucositis (n=50), gingivitis (n=50), peri-implantitis (n=50) and periodontitis (n=50). RESULTS: The pattern of peri-implant bacterial frequency was not as expected (peri-implantitis>mucositis>health). Except for P. intermedia (p>0.05), bacterial frequency was higher in peri-implantitis than health (p<0.05). The frequency of P.gingivalis and red complex species were higher in peri-implantitis than mucositis (p<0.05). In periodontal samples, T. forsythia and T. denticola showed the expected pattern of frequency (periodontitis>gingivitis>health). The frequencies of C. rectus and T. forsythia were higher in healthy teeth/gingivitis than healthy implants/mucositis, respectively (p<0.05). The frequency of P. gingivalis and A. actinomycetemcomitans were similar between periodontitis and peri-implantitis (p>0.05) while all other species occurrences were higher in periodontitis than peri-implantitis (p<0.05). CONCLUSIONS: Bacterial frequency increased from peri-implant/periodontal health to peri-implantitis/periodontitis but not from mucositis/gingivitis to peri-implantitis/periodontitis. There was a trend towards higher bacterial frequency in teeth than implants.
Assuntos
Periodontite Crônica/microbiologia , Implantes Dentários/microbiologia , Gengivite/microbiologia , Bactérias Gram-Negativas/isolamento & purificação , Peri-Implantite/microbiologia , Periodonto/microbiologia , Estomatite/microbiologia , Infecções por Actinobacillus/microbiologia , Adulto , Aggregatibacter actinomycetemcomitans/isolamento & purificação , Perda do Osso Alveolar/microbiologia , Carga Bacteriana , Infecções por Bacteroidaceae/microbiologia , Bacteroides/isolamento & purificação , Infecções por Bacteroides/microbiologia , Infecções por Campylobacter/microbiologia , Campylobacter rectus/isolamento & purificação , Estudos Transversais , Feminino , Hemorragia Gengival/microbiologia , Humanos , Masculino , Pessoa de Meia-Idade , Perda da Inserção Periodontal/microbiologia , Bolsa Periodontal/microbiologia , Porphyromonas gingivalis/isolamento & purificação , Prevotella intermedia/isolamento & purificação , Treponema denticola/isolamento & purificação , Infecções por Treponema/microbiologiaRESUMO
Animal models of infection have been used to demonstrate the therapeutic failure of "bioequivalent" generic products, but their applicability for this purpose requires the accurate identification of those products that are truly bioequivalent. Here, we present data comparing one intravenous generic product of metronidazole with the innovator product in a neutropenic mouse thigh anaerobic infection model. Simultaneous experiments allowed comparisons (generic versus innovator) of potency and the concentration of the active pharmaceutical ingredient (API), analytical chemistry (liquid chromatography/mass spectrometry [LC/MS]), in vitro susceptibility testing, single-dose serum pharmacokinetics (PK) in infected mice, and in vivo pharmacodynamics (PD) against Bacteroides fragilis ATCC 25825 in synergy with Escherichia coli SIG-1 in the neutropenic mouse thigh anaerobic infection model. The Hill dose-response model followed by curve-fitting analysis was used to calculate and compare primary and secondary PD parameters. The generic and the innovator products were identical in terms of the concentration and potency of the API, chromatographic and spectrographic profiles, MIC and minimal bactericidal concentrations (MBC) (2.0 mg/liter), and mouse PK. We found no differences between products in bacteriostatic doses (BD) (15 to 22 mg/kg of body weight per day) or the doses needed to kill 1 log (1LKD) (21 to 29 mg/kg per day) or 2 logs (2LKD) (28 to 54 mg/kg per day) of B. fragilis under dosing schedules of every 12 h (q12h), q8h, or q6h. The area under the concentration-time curve over 24 h in the steady state divided by the MIC (AUC/MIC ratio) was the best PD index to predict the antibacterial efficacy of metronidazole (adjusted coefficient of determination [AdjR(2)] = 84.6%), and its magnitude to reach bacteriostasis in vivo (56.6 ± 5.17 h) or to kill the first (90.8 ± 9.78 h) and second (155.5 ± 22.2 h) logs was the same for both products. Animal models of infection allow a thorough demonstration of the therapeutic equivalence of generic antimicrobials.
Assuntos
Antibacterianos/farmacocinética , Bacteroides fragilis/efeitos dos fármacos , Medicamentos Genéricos/farmacocinética , Metronidazol/farmacocinética , Staphylococcus aureus/efeitos dos fármacos , Animais , Antibacterianos/farmacologia , Área Sob a Curva , Infecções por Bacteroides/tratamento farmacológico , Infecções por Bacteroides/microbiologia , Bacteroides fragilis/fisiologia , Cromatografia Líquida , Medicamentos Genéricos/farmacologia , Feminino , Injeções Intravenosas , Espectrometria de Massas , Metronidazol/farmacologia , Camundongos , Testes de Sensibilidade Microbiana , Neutropenia/complicações , Neutropenia/tratamento farmacológico , Neutropenia/microbiologia , Infecções Estafilocócicas/complicações , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/fisiologia , Equivalência Terapêutica , Coxa da Perna/microbiologiaRESUMO
Endocarditis due to Bacteroides fragilis is a rare disorder. This article describes a case of Bacteroides fragilis endocarditis associated with portal and superior mesenteric venous thrombosis in a patient without preexisting valvular heart disease and review the cases of endocarditis due to this anaerobic bacterium in medical literature since 1980.
Assuntos
Infecções por Bacteroides/diagnóstico , Bacteroides fragilis/isolamento & purificação , Endocardite Bacteriana/diagnóstico , Veias Mesentéricas , Trombose Venosa/diagnóstico , Humanos , Masculino , Pessoa de Meia-Idade , Trombose Venosa/etiologiaRESUMO
Endocarditis due to Bacteroides fragilis is a rare disorder. This article describes a case of Bacteroides fragilis endocarditis associated with portal and superior mesenteric venous thrombosis in a patient without preexisting valvular heart disease and review the cases of endocarditis due to this anaerobic bacterium in medical literature since 1980.
Assuntos
Humanos , Masculino , Pessoa de Meia-Idade , Infecções por Bacteroides/diagnóstico , Bacteroides fragilis/isolamento & purificação , Endocardite Bacteriana/diagnóstico , Veias Mesentéricas , Trombose Venosa/diagnóstico , Trombose Venosa/etiologiaRESUMO
INTRODUCTION: Acute endodontic infections harbor heterogeneous microbial communities in both the root canal (RC) system and apical tissues. Data comparing the microbial structure and diversity in endodontic infections in related ecosystems, such as RC with necrotic pulp and acute apical abscess (AAA), are scarce in the literature. The aim of this study was to examine the presence of selected endodontic pathogens in paired samples from necrotic RC and AAA using polymerase chain reaction (PCR) followed by the construction of cluster profiles. METHODS: Paired samples of RC and AAA exudates were collected from 20 subjects and analyzed by PCR for the presence of selected strict and facultative anaerobic strains. The frequency of species was compared between the RC and the AAA samples. A stringent neighboring clustering algorithm was applied to investigate the existence of similar high-order groups of samples. A dendrogram was constructed to show the arrangement of the sample groups produced by the hierarchical clustering. RESULTS: All samples harbored bacterial DNA. Porphyromonas endodontalis, Prevotella nigrescens, Filifactor alocis, and Tannerela forsythia were frequently detected in both RC and AAA samples. The selected anaerobic species were distributed in diverse small bacteria consortia. The samples of RC and AAA that presented at least one of the targeted microorganisms were grouped in small clusters. CONCLUSIONS: Anaerobic species were frequently detected in acute endodontic infections and heterogeneous microbial communities with low clustering behavior were observed in paired samples of RC and AAA.