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1.
Sci Rep ; 12(1): 6454, 2022 04 19.
Artigo em Inglês | MEDLINE | ID: mdl-35440801

RESUMO

This study aimed to assess the ultrapure cannabidiol (CBD) antibacterial activity and to investigate the antibacterial activity of the combination CBD + polymyxin B (PB) against Gram-negative (GN) bacteria, including PB-resistant Gram-negative bacilli (GNB). We used the standard broth microdilution method, checkerboard assay, and time-kill assay. CBD exhibited antibacterial activity against Gram-positive bacteria, lipooligosaccharide (LOS)-expressing GN diplococcus (GND) (Neisseria gonorrhoeae, Neisseria meningitidis, Moraxella catarrhalis), and Mycobacterium tuberculosis, but not against GNB. For most of the GNB studied, our results showed that low concentrations of PB (≤ 2 µg/mL) allow CBD (≤ 4 µg/mL) to exert antibacterial activity against GNB (e.g., Klebsiella pneumoniae, Escherichia coli, Acinetobacter baumannii), including PB-resistant GNB. CBD + PB also showed additive and/or synergistic effect against LOS-expressing GND. Time-kill assays results showed that the combination CBD + PB leads to a greater reduction in the number of colony forming units per milliliter compared to CBD and PB alone, at the same concentration used in combination, and the combination CBD + PB was synergistic for all four PB-resistant K. pneumoniae isolates evaluated. Our results show that CBD has translational potential and should be further explored as a repurposed antibacterial agent in clinical trials. The antibacterial efficacy of the combination CBD + PB against multidrug-resistant and extensively drug-resistant GNB, especially PB-resistant K. pneumoniae, is particularly promising.


Assuntos
Canabidiol , Polimixina B , Antibacterianos/farmacologia , Canabidiol/farmacologia , Reposicionamento de Medicamentos , Farmacorresistência Bacteriana Múltipla , Sinergismo Farmacológico , Bactérias Gram-Negativas , Klebsiella pneumoniae , Testes de Sensibilidade Microbiana , Polimixina B/farmacologia
3.
Front Microbiol ; 9: 539, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29628916

RESUMO

Bacterial resistance to antibiotics is concern in healthcare-associated infections. On the other hand, bacterial tolerance to other antimicrobials, like heavy metals, has been neglected and underestimated in hospital pathogens. Silver has long been used as an antimicrobial agent and it seems to be an important indicator of heavy metal tolerance. To explore this perspective, we searched for the presence of acquired silver resistance genes (sil operon: silE, silS, silR, silC, silF, silB, silA, and silP) and acquired extended-spectrum cephalosporin and carbapenem resistance genes (blaCTX-M and blaKPC) in Enterobacter cloacae Complex (EcC) (n = 27) and Enterobacter aerogenes (n = 8) isolated from inpatients at a general hospital. Moreover, the genetic background of the silA (silver-efflux pump) and the presence of other acquired heavy metal tolerance genes, pcoD (copper-efflux pump), arsB (arsenite-efflux pump), terF (tellurite resistance protein), and merA (mercuric reductase) were also investigated. Outstandingly, 21/27 (78%) EcC isolates harbored silA gene located in the chromosome. Complete sil operon was found in 19/21 silA-positive EcC isolates. Interestingly, 8/20 (40%) E. hormaechei and 5/6 (83%) E. asburiae co-harbored silA/pcoD genes and blaCTX-M-(15,2,or9) and/or blaKPC-2 genes. Frequent occurrences of arsB, terF, and merA genes were detected, especially in silA/pcoD-positive, multidrug-resistant (MDR) and/or CTX-M-producing isolates. Our study showed co-presence of antibiotic and heavy metal tolerance genes in MDR EcC isolates. In our viewpoint, there are few studies regarding to bacterial heavy metal tolerance and we call attention for more investigations and discussion about this issue in different hospital pathogens.

4.
Sci Rep ; 7(1): 17658, 2017 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-29247243

RESUMO

Leukotriene B4 (LTB4) is essential for host immune defence. It increases neutrophil recruitment, phagocytosis and pathogen clearance, and decreases oedema and inflammasome activation. The host response and the role of LTB4 during Achromobacter xylosoxidans infection remain unexplored. Wild-type (129sv) and LTB4 deficient (Alox5 -/-) mice were intratracheally infected with A. xylosoxidans. Wild-type 129sv infected mice survived beyond the 8th day post-infection, exhibited increased levels of LTB4 in the lung on the 1st day, while levels of PGE2 increased on the 7th day post-infection. Infected Alox5 -/- mice showed impaired bacterial clearance, increased lung inflammation, and succumbed to the infection by the 7th day. We found that exogenous LTB4 does not affect the phagocytosis of A. xylosoxidans by alveolar macrophages in vitro. However, treatment of infected animals with LTB4 protected from mortality, by reducing the bacterial load and inflammation via BLT1 signalling, the high affinity receptor for LTB4. Of importance, we uncovered that LTB4 induces gene and protein expression of α-defensin-1 during the infection. This molecule is essential for bacterial clearance and exhibits potent antimicrobial activity by disrupting A. xylosoxidans cell wall. Taken together, our data demonstrate a major role for LTB4 on the control of A. xylosoxidans infection.


Assuntos
Achromobacter denitrificans/fisiologia , Infecções por Bactérias Gram-Negativas/imunologia , Inflamação/imunologia , Leucotrieno B4/metabolismo , Pulmão/imunologia , Macrófagos Alveolares/imunologia , Proteínas Ativadoras de 5-Lipoxigenase/genética , Animais , Carga Bacteriana , Células Cultivadas , Dinoprostona/metabolismo , Camundongos , Camundongos da Linhagem 129 , Camundongos Knockout , Fagocitose , Receptores do Leucotrieno B4/metabolismo , Transdução de Sinais , alfa-Defensinas/metabolismo
5.
APMIS ; 123(2): 128-35, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25257819

RESUMO

This study was designed to characterize a collection of 60 enteropathogenic Escherichia coli (EPEC) isolates from diarrheic feces of patients in the Ribeirão Preto metropolitan area regarding different phenotypic and molecular features. We examined antibiotic resistance profiles, occurrence of virulence factors-encoding genes, intimin subtypes and the correlation of serotypes among typical (tEPEC) and atypical (aEPEC) EPEC isolates. The results demonstrated that atypical EPEC was more heterogeneous than typical EPEC concerning the characteristics investigated and 45.2% do not belong to classical EPEC serogroups. Intimin subtype ß was the most frequent among the EPEC isolates (46.7%), being detected in both tEPEC and aEPEC. The majority of aEPEC isolates presented localized adherence-like (LAL) pattern to HEp-2 cells, although aEPEC isolates displaying diffuse adherence (DA) or non-adherent were also detected. High prevalence of antimicrobial resistance was found for ampicillin, cephalothin, sulfonamide and tetracycline. In general, tEPEC isolates were more resistant to the antimicrobials tested than aEPEC isolates.


Assuntos
Escherichia coli Enteropatogênica/efeitos dos fármacos , Escherichia coli Enteropatogênica/genética , Ampicilina/farmacologia , Antibacterianos/farmacologia , Aderência Bacteriana/genética , Brasil/epidemiologia , Linhagem Celular , Cefalotina/farmacologia , Pré-Escolar , Diarreia/microbiologia , Farmacorresistência Bacteriana Múltipla , Escherichia coli Enteropatogênica/isolamento & purificação , Infecções por Escherichia coli/tratamento farmacológico , Fezes/microbiologia , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Testes de Sensibilidade Microbiana , Sorotipagem , Sulfonamidas/farmacologia , Tetraciclina/farmacologia , Fatores de Virulência/genética
6.
Braz. J. Microbiol. ; 43(4): 1309-1314, Oct.-Dec. 2012. tab
Artigo em Inglês | VETINDEX | ID: vti-2151

RESUMO

Mutations in the quinolone resistance-determining regions (QRDR) in chromosomal gyrA and parC genes and fluoroquinolone susceptibility profiles were investigated in quinolone-resistant Enterobacteriaceae isolated from community and hospitalized patientsin the Brazilian Southeast region. A total of 112 nalidixic acid-resistant enterobacterial isolates collected from 2000 to 2005 were investigated for mutations in the topoisomerases genes gyrA and parC by amplifying and sequencing the QRDR regions. Susceptibility to fluoroquinolones was tested by the agar dilution method. Amongst the 112 enterobacterial isolates, 81 (72.3%) were resistant to ciprofloxacin and 5 (4.5%) showed reduced susceptibility. Twenty-six (23.2%) were susceptible to ciprofloxacin. Several alterations were detected in gyrA and parC genes. Escherichia coli isolates (47.7%) showed double mutations in the gyrA gene and a single one in the parC gene. Two unusual aminoacid substitutions are reported, an Asp87-Asn in a Citrobacter freundii isolate with reduced susceptibility to fluoroquinolones and a Glu84-Ala in one E. coli isolate.Only a parC gene mutation was found in fluoroquinolone-susceptible Enterobacter aerogenes. None of the isolates susceptible to ciprofloxacin presented mutations in topoisomerase genes. This comprehensive analysis of QRDRs in gyrA and parC genes, covering commonly isolated Enterobacteriaceae in Brazil is the largest reported up to now.(AU)


Assuntos
DNA Girase/genética , DNA Topoisomerase IV/genética , Mutação , Enterobacteriaceae/patogenicidade
7.
Braz. j. microbiol ; 43(4): 1309-1314, Oct.-Dec. 2012. tab
Artigo em Inglês | LILACS | ID: lil-665813

RESUMO

Mutations in the quinolone resistance-determining regions (QRDR) in chromosomal gyrA and parC genes and fluoroquinolone susceptibility profiles were investigated in quinolone-resistant Enterobacteriaceae isolated from community and hospitalized patientsin the Brazilian Southeast region. A total of 112 nalidixic acid-resistant enterobacterial isolates collected from 2000 to 2005 were investigated for mutations in the topoisomerases genes gyrA and parC by amplifying and sequencing the QRDR regions. Susceptibility to fluoroquinolones was tested by the agar dilution method. Amongst the 112 enterobacterial isolates, 81 (72.3%) were resistant to ciprofloxacin and 5 (4.5%) showed reduced susceptibility. Twenty-six (23.2%) were susceptible to ciprofloxacin. Several alterations were detected in gyrA and parC genes. Escherichia coli isolates (47.7%) showed double mutations in the gyrA gene and a single one in the parC gene. Two unusual aminoacid substitutions are reported, an Asp87-Asn in a Citrobacter freundii isolate with reduced susceptibility to fluoroquinolones and a Glu84-Ala in one E. coli isolate.Only a parC gene mutation was found in fluoroquinolone-susceptible Enterobacter aerogenes. None of the isolates susceptible to ciprofloxacin presented mutations in topoisomerase genes. This comprehensive analysis of QRDRs in gyrA and parC genes, covering commonly isolated Enterobacteriaceae in Brazil is the largest reported up to now.


Assuntos
Humanos , /análise , /isolamento & purificação , Ácido Nalidíxico/isolamento & purificação , Sequência de Bases , DNA Girase/isolamento & purificação , DNA Topoisomerases/análise , DNA Topoisomerases/isolamento & purificação , Predisposição Genética para Doença , Mutação , Métodos , Pacientes , Métodos
8.
Braz J Microbiol ; 43(4): 1309-14, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24031957

RESUMO

Mutations in the quinolone resistance-determining regions (QRDR) in chromosomal gyrA and parC genes and fluoroquinolone susceptibility profiles were investigated in quinolone-resistant Enterobacteriaceae isolated from community and hospitalized patients in the Brazilian Southeast region. A total of 112 nalidixic acid-resistant enterobacterial isolates collected from 2000 to 2005 were investigated for mutations in the topoisomerases genes gyrA and parC by amplifying and sequencing the QRDR regions. Susceptibility to fluoroquinolones was tested by the agar dilution method. Amongst the 112 enterobacterial isolates, 81 (72.3%) were resistant to ciprofloxacin and 5 (4.5%) showed reduced susceptibility. Twenty-six (23.2%) were susceptible to ciprofloxacin. Several alterations were detected in gyrA and parC genes. Escherichia coli isolates (47.7%) showed double mutations in the gyrA gene and a single one in the parC gene. Two unusual aminoacid substitutions are reported, an Asp87-Asn in a Citrobacter freundii isolate with reduced susceptibility to fluoroquinolones and a Glu84-Ala in one E. coli isolate. Only a parC gene mutation was found in fluoroquinolone-susceptible Enterobacter aerogenes. None of the isolates susceptible to ciprofloxacin presented mutations in topoisomerase genes. This comprehensive analysis of QRDRs in gyrA and parC genes, covering commonly isolated Enterobacteriaceae in Brazil is the largest reported up to now.

9.
Can J Microbiol ; 55(6): 672-9, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19767837

RESUMO

Enteropathogenic Escherichia coli (EPEC) infections are a leading cause of infantile diarrhea in developing nations. Multilocus sequence typing (MLST) characterizes bacterial strains based on the sequences of internal fragments in housekeeping genes. Little is known about strains of EPEC analyzed by MLST from Brazil. In this study, a diverse collection of 29 EPEC strains isolated from patients with diarrhea, admitted to the University Hospital of Ribeirao Preto, was characterized by MLST. Strain analysis demonstrated 22 different sequence types (STs), of which almost half (48%) were new, indicating a high genotype diversity. The 22 STs were divided by eBURST into 12 clonal complexes. It was not possible to correlate typical and atypical EPEC with other strains in the MLST database. This is the first study that analyzed EPEC strains from South America that are included in the E. coli MLST database. Nine (31%) out of 29 strains are part of the CC10 clonal complex, the major clonal complex in the database, which comprises 174 strains and 86 different STs, suggesting that these strains might be the most important intestinal pathogenic E. coli worldwide. Genetic relationships between typical and atypical EPEC, enterohemorrhagic E. coli, and enteroaggregative E. coli strains were not established by MLST.


Assuntos
Diarreia/microbiologia , Escherichia coli Enteropatogênica/isolamento & purificação , Infecções por Escherichia coli/microbiologia , Técnicas de Tipagem Bacteriana , Brasil , Escherichia coli Enteropatogênica/classificação , Escherichia coli Enteropatogênica/genética , Humanos , Dados de Sequência Molecular , Filogenia
10.
Diagn Microbiol Infect Dis ; 65(2): 202-6, 2009 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19748435

RESUMO

Two hundred fifty-seven nalidixic acid-resistant enterobacterial isolates were collected in a Brazilian community from January 2000 to May 2005 to determine the prevalence of plasmid-encoded extended-spectrum beta-lactamases. The bla(CTX-M) genetic environment was determined by polymerase chain reaction and sequencing. Eleven isolates (4.2%) harbored a bla(CTX-M-2) gene, 3 isolates bla(CTX-M-9), 2 isolates bla(CTX-M-8), and 6 isolates bla(SHV-5). Two novel bla(CTX-M-2) variants, namely, bla(CTX-M-74) and bla(CTX-M-75), were identified.


Assuntos
Infecções por Enterobacteriaceae/microbiologia , Enterobacteriaceae/enzimologia , Enterobacteriaceae/genética , beta-Lactamases/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Antibacterianos/farmacologia , Brasil , Criança , Pré-Escolar , Enterobacteriaceae/isolamento & purificação , Feminino , Humanos , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Pacientes Ambulatoriais , Plasmídeos , Reação em Cadeia da Polimerase , Análise de Sequência de DNA , Resistência beta-Lactâmica , beta-Lactamases/classificação , beta-Lactamas/farmacologia
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