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1.
Anal Bioanal Chem ; 412(4): 871-880, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31901958

RESUMO

Novel carbon dots (CDs) were synthesized by a one-pot hydrothermal approach using ampicillin as a precursor, and the as-prepared CDs exhibited a high quantum yield (23%). The CDs were found to possess abundant surface functional groups, thus providing good permeability to the cell, and the antibacterial activity of CDs was evaluated. S. aureus and L. monocytogenes were selected as model bacteria, and our results showed that the CDs exhibited antibacterial activity against S. aureus and L. monocytogenes under visible light illumination, even at low concentrations. The antibacterial mechanism is believed to be the production of reactive oxygen species (ROS) from CDs under visible light irradiation, which attacked the bacterial cell membranes, resulting in the death of the bacteria. In addition, because of the multicolor fluorescence properties of CDs, staining of S. aureus and L. monocytogenes obtained multicolor fluorescence images at different excitation wavelengths. Based on these results, CDs are a promising candidate material for biological applications. Graphical abstract.


Assuntos
Ampicilina/farmacologia , Antibacterianos/farmacologia , Carbono/farmacologia , Listeria monocytogenes/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Ampicilina/análogos & derivados , Ampicilina/síntese química , Antibacterianos/síntese química , Antibacterianos/química , Carbono/química , Humanos , Listeriose/tratamento farmacológico , Nanopartículas/química , Infecções Estafilocócicas/tratamento farmacológico
2.
Int J Nanomedicine ; 14: 7281-7289, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31686808

RESUMO

Purpose: This work presents the preparation of a nanocomposite of ampicillin-conjugated gold nanoparticles (AuNPs) and self-assembled rosette nanotubes (RNTs), and evaluates its antibacterial properties against two strains of drug-resistant bacteria (Staphylococcus aureus [S. aureus], methicillin-resistant S. aureus [MRSA]). Materials and methods: Small, nearly monodisperse AuNPs (1.43±0.5 nm in diameter) nucleated on the surface of polyethylene glycol-functionalized RNTs in a one-pot reaction. Upon conjugation with ampicillin, their diameter increased to 1.86±0.32 nm. The antibacterial activity of the nanocomposite against S. aureus and MRSA was tested using different concentrations of ampicillin. The cytocompatibility of the nanocomposite was also tested against human dermal fibroblasts. Results: Based on bacterial inhibition studies, the nanocomposite demonstrated enhanced antibiotic activity against both bacterial strains. The minimum inhibitory concentration (MIC) of the nanocomposite against S. aureus was found to be 0.58 µg/mL, which was 18% lower than ampicillin alone. The nanocomposite also exhibited a 20 hrs MIC of 4 µg/mL against MRSA, approximately 10-20 times lower than previously reported values for ampicillin alone. In addition, at concentrations of 4 µg/mL of ampicillin (70 µg/mL of AuNPs), the nanocomposite showed negligible cytotoxic effects. Conclusion: Our findings offer a new approach for the treatment of drug-resistant bacteria by potentiating inhibitory effects of existing antibiotics, and delivering them using a non-toxic formulation.


Assuntos
Ampicilina/farmacologia , Antibacterianos/farmacologia , Ouro/química , Nanopartículas Metálicas/química , Nanotubos/química , Polietilenoglicóis/química , Sobrevivência Celular/efeitos dos fármacos , Derme/citologia , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Humanos , Nanopartículas Metálicas/ultraestrutura , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Nanotubos/ultraestrutura
3.
PLoS Biol ; 17(10): e3000515, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31652256

RESUMO

Evolved resistance to one antibiotic may be associated with "collateral" sensitivity to other drugs. Here, we provide an extensive quantitative characterization of collateral effects in Enterococcus faecalis, a gram-positive opportunistic pathogen. By combining parallel experimental evolution with high-throughput dose-response measurements, we measure phenotypic profiles of collateral sensitivity and resistance for a total of 900 mutant-drug combinations. We find that collateral effects are pervasive but difficult to predict because independent populations selected by the same drug can exhibit qualitatively different profiles of collateral sensitivity as well as markedly different fitness costs. Using whole-genome sequencing of evolved populations, we identified mutations in a number of known resistance determinants, including mutations in several genes previously linked with collateral sensitivity in other species. Although phenotypic drug sensitivity profiles show significant diversity, they cluster into statistically similar groups characterized by selecting drugs with similar mechanisms. To exploit the statistical structure in these resistance profiles, we develop a simple mathematical model based on a stochastic control process and use it to design optimal drug policies that assign a unique drug to every possible resistance profile. Stochastic simulations reveal that these optimal drug policies outperform intuitive cycling protocols by maintaining long-term sensitivity at the expense of short-term periods of high resistance. The approach reveals a new conceptual strategy for mitigating resistance by balancing short-term inhibition of pathogen growth with infrequent use of drugs intended to steer pathogen populations to a more vulnerable future state. Experiments in laboratory populations confirm that model-inspired sequences of four drugs reduce growth and slow adaptation relative to naive protocols involving the drugs alone, in pairwise cycles, or in a four-drug uniform cycle.


Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana Múltipla/genética , Enterococcus faecalis/efeitos dos fármacos , Genoma Bacteriano , Modelos Estatísticos , Ampicilina/farmacologia , Evolução Molecular Direcionada , Relação Dose-Resposta a Droga , Combinação de Medicamentos , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Sinergismo Farmacológico , Enterococcus faecalis/genética , Enterococcus faecalis/crescimento & desenvolvimento , Enterococcus faecalis/metabolismo , Fosfomicina/farmacologia , Aptidão Genética , Testes de Sensibilidade Microbiana , Mutação , Rifampina/farmacologia , Seleção Genética , Processos Estocásticos , Tigeciclina/farmacologia , Sequenciamento Completo do Genoma
4.
Rev Esp Quimioter ; 32(5): 465-468, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31515975

RESUMO

OBJECTIVE: To evaluate if the in vitro activity of ampicillin increases when combined with ceftriaxone. METHODS: The activity of ampicillin and ceftriaxone was evaluated against six Listeria monocytogenes invasive clinical isolates. Ampicillin and ceftriaxone MICs were determined by the broth microdilution method. Synergy was evaluated by checkerboard and time-kill curves methods. RESULTS: All six L. monocytogenes strains were susceptible to ampicillin (MICs 0.25-0.5 mg/L). A bacteriostatic synergy was demonstrated by the FIC index of 0.5 and a 2.5 log10 CFU reduction on the six strains studied for MIC ampicillin plus 16 mg/L ceftriaxone concentrations. CONCLUSIONS: The association of ceftriaxone with ampicillin increases the in vitro activity of ampicillin, and therefore could be a valuable option in the treatment of invasive infection by L. monocytogenes.


Assuntos
Ampicilina/farmacologia , Antibacterianos/farmacologia , Ceftriaxona/farmacologia , Listeria monocytogenes/efeitos dos fármacos , Sinergismo Farmacológico , Quimioterapia Combinada/métodos , Técnicas In Vitro , Testes de Sensibilidade Microbiana
5.
J Med Microbiol ; 68(10): 1534-1539, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31368885

RESUMO

Introduction. Certain nontypeable Haemophilus influenzae cannot be assigned a sequence type (ST) by Multilocus Sequence Typing (MLST) due to the lack of the fucK gene, one of seven MLST loci in H. influenzae, which encodes a fucose-operon enzyme.Aims. To confirm whether the loss of fucK is also found in the encapsulated strains, we analysed clinical isolates of H. influenzae serotype e (Hie).Methodology. We conducted MLST, PFGE, and antimicrobial susceptibility tests of 45 Hie strains; the majority (n=43) were derived from respiratory samples of pediatric patients at Chiba Children's Hospital between 2000 and 2016. The two remaining strains were obtained from the blood of elderly patients with invasive H. influenzae diseases (IHiDs) between 2015 and 2016 at general hospitals. For the fucK-negative strains, PCR analysis for fucose operon was also performed.Results. Four STs (ST18, 122, 621 and 1758) were assigned to 13 strains, and remaining 32 (including one associated with IHiD) were fucK-negative, completely missing the fucose operon. The allelic profiles of six other loci were identical among 31 strains and to that of ST18, 122 and 621, and these strains were genetically closely related. Forty of 45 isolates were ampicillin-sensitive.Conclusions. The loss of fucK was frequently observed in clinical isolates of Hie from children. Moreover, fucK-negative Hie may be the cause of IHiD in adult patients. The majority of Hie, including fucK-negative strains, were shown to be clonally related and were ampicillin sensitive. This represents the first report examining fucK losses in encapsulated H. influenzae.


Assuntos
Proteínas de Bactérias/genética , Infecções por Haemophilus/microbiologia , Haemophilus influenzae/isolamento & purificação , Fosfotransferases (Aceptor do Grupo Álcool)/genética , Adolescente , Ampicilina/farmacologia , Antibacterianos/farmacologia , Proteínas de Bactérias/metabolismo , Criança , Pré-Escolar , Feminino , Haemophilus influenzae/classificação , Haemophilus influenzae/efeitos dos fármacos , Haemophilus influenzae/genética , Humanos , Japão , Masculino , Tipagem de Sequências Multilocus , Óperon , Fosfotransferases (Aceptor do Grupo Álcool)/deficiência , Filogenia
6.
Lett Appl Microbiol ; 69(4): 286-293, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31392736

RESUMO

The prevalence of Listeria monocytogenes in the retail fish markets of the Kerala, India was investigated by screening 227 samples comprising of marine finfish (n = 97) shellfish (n = 19), ready-to-cook fish products (n = 47), ready-to-eat fish products (n = 10), dried fish (n = 11) and retail ice (n = 43). The prevalence of L. monocytogenes and L. innocua was 2·7% and 17·2% respectively. Sample category wise, prevalence of L. monocytogenes was higher in marine finfish (1·8%) and retail ice (0·9%). All the L. monocytogenes isolates carried virulent genes namely inlA, inlC, inlJ, hlyA, iap, plcA, prfA genes and majority (82%) belonged to 1/2a, 3a serogroups. L. monocytogenes isolates were multidrug-resistant and showed resistance to ampicillin, penicillin, erythromycin, tetracycline and clindamycin. Enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR) delineated 58% genetic heterogeneity among the L. monocytogenes strains. The study reports that genetic similarities of the isolates were interlinked to their serogroup and sample origin. SIGNIFICANCE AND IMPACT OF THE STUDY: Prevalence of Listeria monocytogenes, in the retail fish markets of Kerala, India was low but their relatively higher presence in marine finfish and retail ice and virulent nature of the isolates signifies food safety concerns. Moreover, multidrug-resistant nature of these isolates may potentially lead to spread of antimicrobial resistance. This study identified retail ice as a vehicle for entry of L. monocytogenes in retail fish and hence, there is a need to ensure quality of retail ice used for maintaining the cold-chain.


Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana Múltipla/genética , Listeria monocytogenes/efeitos dos fármacos , Alimentos Marinhos/microbiologia , Frutos do Mar/microbiologia , Ampicilina/farmacologia , Animais , Clindamicina/farmacologia , Eritromicina/farmacologia , Pesqueiros , Peixes/microbiologia , Microbiologia de Alimentos , Inocuidade dos Alimentos , Heterogeneidade Genética , Gelo/análise , Índia , Listeria monocytogenes/genética , Listeria monocytogenes/isolamento & purificação , Penicilinas/farmacologia , Prevalência , Sorogrupo , Tetraciclina/farmacologia
7.
Molecules ; 24(16)2019 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-31426567

RESUMO

A series of twenty-six methoxylated and methylated N-aryl-1-hydroxynaphthalene- 2-carboxanilides was prepared and characterized as potential anti-invasive agents. The molecular structure of N-(2,5-dimethylphenyl)-1-hydroxynaphthalene-2-carboxamide as a model compound was determined by single-crystal X-ray diffraction. All the analysed compounds were tested against the reference strain Staphylococcus aureus and three clinical isolates of methicillin-resistant S. aureus as well as against Mycobacterium tuberculosis and M. kansasii. In addition, the inhibitory profile of photosynthetic electron transport in spinach (Spinacia oleracea L.) chloroplasts was specified. In vitro cytotoxicity of the most effective compounds was tested on the human monocytic leukaemia THP-1 cell line. The activities of N-(3,5-dimethylphenyl)-, N-(3-fluoro-5-methoxy-phenyl)- and N-(3,5-dimethoxyphenyl)-1-hydroxynaphthalene-2-carbox- amide were comparable with or even better than the commonly used standards ampicillin and isoniazid. All promising compounds did not show any cytotoxic effect at the concentration >30 µM. Moreover, an in silico evaluation of clogP features was performed for the entire set of the carboxamides using a range of software lipophilicity predictors, and cross-comparison with the experimentally determined lipophilicity (log k), in consensus lipophilicity estimation, was conducted as well. Principal component analysis was employed to illustrate noticeable variations with respect to the molecular lipophilicity (theoretical/experimental) and rule-of-five violations. Additionally, ligand-oriented studies for the assessment of the three-dimensional quantitative structure-activity relationship profile were carried out with the comparative molecular surface analysis to determine electron and/or steric factors that potentially contribute to the biological activities of the investigated compounds.


Assuntos
Anilidas/farmacologia , Antibacterianos/farmacologia , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Mycobacterium kansasii/efeitos dos fármacos , Mycobacterium tuberculosis/efeitos dos fármacos , Naftóis/farmacologia , Ampicilina/farmacologia , Anilidas/síntese química , Anilidas/química , Antibacterianos/síntese química , Antibacterianos/química , Cloroplastos/efeitos dos fármacos , Cloroplastos/fisiologia , Transporte de Elétrons/efeitos dos fármacos , Humanos , Isoniazida/farmacologia , Staphylococcus aureus Resistente à Meticilina/crescimento & desenvolvimento , Metilação , Testes de Sensibilidade Microbiana , Mycobacterium kansasii/crescimento & desenvolvimento , Mycobacterium tuberculosis/crescimento & desenvolvimento , Naftóis/síntese química , Naftóis/química , Fotossíntese/efeitos dos fármacos , Análise de Componente Principal , Spinacia oleracea/química , Spinacia oleracea/efeitos dos fármacos , Spinacia oleracea/metabolismo , Relação Estrutura-Atividade , Células THP-1
8.
BMC Infect Dis ; 19(1): 746, 2019 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-31455256

RESUMO

BACKGROUND: Antimicrobial resistance is one of the most serious public health threats of the twenty-first century. The implementation of AMR surveillance in Zimbabwe is limited. However, data from a private laboratory in Harare revealed increasing resistance rates to common antibiotics like ampicillin (i.e., from 73.9% in 2011 to 74.6% in 2015). The increasing resistance rates indicate that Zimbabwe is affected by AMR. This study was done to determine the magnitude of AMR in Harare and determine the trends of AMR to first-line and to last-resort antibiotics and make recommendations to mitigate the problem. METHODS: A retrospective record review of data collected from the microbiology department at a private laboratory between January 2012 and December 2017 was done. The outcome of interest was the antibiotic susceptibility of bacterial isolates. Microsoft Excel 2016 was used to plot trends from 2012 to 2017 and Epi Info™7 was used for statistical analysis. RESULTS: A total of 23,432 isolates, of 12 medically important bacteria were analysed. Forty-three percent of the isolates were from urines, 36.7% were from pus swabs and 7% were from blood. The most common pathogen was Escherichia coli (43.2%), followed by Staphylococcus aureus (15.8%) and the least common was Neisseria gonorrhoea (0.2%). Resistance was highest to ampicillin followed by penicillin, both ranging between 70 and 100% over the six years. Statistically significant increases in resistance to commonly used antibiotics were observed in amoxicillin-resistant E. coli and Streptococcus pneumonia and third generation cephalosporin-resistant E. coli. There was an increase in resistance to last-line antibiotics i.e., fluoroquinolone-resistant Salmonella spp. and carbapenem-resistant Pseudomonas aeruginosa and Acinetobacter baumannii. However, methicillin-resistant S. aureus showed a decreasing trend. CONCLUSIONS: There is a high burden of drug resistance to common antibiotics in Harare and an emergence of resistance to last-line antibiotics.


Assuntos
Bactérias/efeitos dos fármacos , Infecções Bacterianas/microbiologia , Farmacorresistência Bacteriana/efeitos dos fármacos , Acinetobacter baumannii/efeitos dos fármacos , Acinetobacter baumannii/isolamento & purificação , Ampicilina/farmacologia , Antibacterianos/farmacologia , Bactérias/isolamento & purificação , Infecções Bacterianas/tratamento farmacológico , Infecções Bacterianas/epidemiologia , Cefalosporinas/farmacologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/isolamento & purificação , Humanos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Testes de Sensibilidade Microbiana , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/isolamento & purificação , Estudos Retrospectivos , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/isolamento & purificação , Zimbábue/epidemiologia
9.
Infect Immun ; 87(10)2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31308086

RESUMO

As important players in the host defense system, commensal microbes and the microbiota influence multiple aspects of host physiology. Bordetella pertussis infection is highly contagious among humans. However, the roles of the microbiota in B. pertussis pathogenesis are poorly understood. Here, we show that antibiotic-mediated depletion of the microbiota results in increased susceptibility to B. pertussis infection during the early stage. The increased susceptibility was associated with a marked impairment of the systemic IgG, IgG2a, and IgG1 antibody responses to B. pertussis infection after antibiotic treatment. Furthermore, the microbiota impacted the short-lived plasma cell responses as well as the recall responses of memory B cells to B. pertussis infection. Finally, we found that the dysbiosis caused by antibiotic treatment affects CD4+ T cell generation and PD-1 expression on CD4+ T cells and thereby perturbs plasma cell differentiation. Our results have revealed the importance of commensal microbes in modulating host immune responses to B. pertussis infection and support the possibility of controlling the severity of B. pertussis infection in humans by manipulating the microbiota.


Assuntos
Bordetella pertussis/imunologia , Disbiose/imunologia , Microbioma Gastrointestinal/imunologia , Imunidade Humoral , Simbiose/imunologia , Coqueluche/imunologia , Ampicilina/farmacologia , Animais , Antibacterianos/farmacologia , Anticorpos Antibacterianos/biossíntese , Anticorpos Antibacterianos/classificação , Bacteroidetes/classificação , Bacteroidetes/efeitos dos fármacos , Bacteroidetes/crescimento & desenvolvimento , Bacteroidetes/imunologia , Bordetella pertussis/crescimento & desenvolvimento , Bordetella pertussis/patogenicidade , Disbiose/microbiologia , Disbiose/fisiopatologia , Feminino , Firmicutes/classificação , Firmicutes/efeitos dos fármacos , Firmicutes/crescimento & desenvolvimento , Firmicutes/imunologia , Microbioma Gastrointestinal/efeitos dos fármacos , Imunidade Inata , Imunoglobulina G/biossíntese , Imunoglobulina G/classificação , Metronidazol/farmacologia , Camundongos , Camundongos Endogâmicos BALB C , Neomicina/farmacologia , Proteobactérias/classificação , Proteobactérias/efeitos dos fármacos , Proteobactérias/crescimento & desenvolvimento , Proteobactérias/imunologia , Simbiose/efeitos dos fármacos , Vancomicina/farmacologia , Coqueluche/microbiologia , Coqueluche/fisiopatologia
10.
BMC Res Notes ; 12(1): 422, 2019 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-31311578

RESUMO

OBJECTIVES: Plasmids harbour antibiotic resistance genes which contribute to the emergence of multidrug resistant pathogens. We detected the presence of plasmids in multidrug resistant Salmonella enterica serovar Typhi (S. Typhi) isolates from our previous study and consequently determined their incompatibility groups and possibility of conjugation transmission. Plasmids were extracted from 98 multidrug resistant S. Typhi isolates based on alkaline lysis technique. Plasmid incompatibility grouping was established by PCR replicon typing using 18 pairs of primers to amplify FIA, FIB, FIC, HI1, HI2, I1-Iγ, L/M, N, P, W, T, A/C, K, B/O, X, Y, F and FIIA replicons. Antibiotic resistance phenotypes were conjugally transferred from S. Typhi isolates with plasmids to Escherichia coli K12F strain devoid of plasmids. RESULTS: Approximately 79.6% of the MDR S. Typhi isolates were related to the existence of plasmids. We detected 93.6% of plasmids belonging to incompatibility (Inc) group HI1. The other incompatibility groups identified included IncFIC (16.7%), IncP (1.3%), and IncI1 (1.3%) which appeared together with Inc HI1. MDR S. Typhi isolated carried a homologous plasmid of incompatibility group HI1 most of which transferred the resistance phenotypes of ampicillin, tetracycline and chloramphenicol to the transconjugants.


Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana Múltipla/genética , Plasmídeos/genética , Salmonella typhi/efeitos dos fármacos , Ampicilina/farmacologia , Cloranfenicol/farmacologia , Conjugação Genética/genética , Escherichia coli/efeitos dos fármacos , Escherichia coli/genética , Humanos , Quênia , Testes de Sensibilidade Microbiana , Replicon/genética , Salmonella typhi/classificação , Salmonella typhi/genética , Tetraciclina/farmacologia , Febre Tifoide/microbiologia
11.
Biomed Res Int ; 2019: 3917841, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31346516

RESUMO

In this study, the prevalence, phenotypes, and clonal relationships of Escherichia coli (E. coli) strains isolated from minks were investigated. In July 2017, a total of 62 fresh faecal swab samples were randomly collected from one large-scale mink farm in Zhucheng, Shandong Province, China. In all the samples, 50 E. coli strains were isolated and then assigned to serotyping, antimicrobial susceptibility test, detection of antimicrobial resistance genes and the Class 1 integrons, and multilocus sequence typing (MLST). Four pathogenic serotypes were identified among all the isolates, while the most common serotype was enterohemorrhagic E. coli O104:H4 (6.0 %). Antimicrobial sensitivity testing revealed that most isolates were susceptible to cefoxitin (96.0 %) and amikacin (82.0 %), while most isolates were resistant to ampicillin (92.0 %) and tetracycline (90.0 %). An analysis of the nucleotide sequences revealed that 7 isolates (14.0%) carried 4 types of Class 1 integron cassette, including dfrA27+aadA2+qnrA (57.1%), dfrA17+aadA5 (14.3%), dfrA12+aadA2 (14.3%), and dfrA1+aadA1 (14.3%). PCR screening showed that 14 antibiotic resistance genes were presented in 50 isolates, while the most prevalent resistance gene was qnrS, which was detected in 60.0 % of isolates, followed by sul2 (40.0%) and oqxA (38.0%). MLST analysis showed that 32 sequence types (STs) were identified, while ST46 was the predominant genotype among all isolates. Clonal complex 3 (CC3) was dominant. Compared with 340 human E. coli STs reported in China, the ST10 clonal complex, known as the largest human clonal complex, was also found in the 50 mink E. coli isolates. Meanwhile, mink-derived strain ST206 formed a new clonal complex, CC206, which was different from human ST strains. Our results showed that farmed minks could be reservoirs of antimicrobial-resistant E. coli with Class 1 integron cassettes and resistance genes, which were likely to pose a threat to public health. Therefore, continuous inspections and monitoring of E. coli in minks are essential for detecting and controlling emerging E. coli with different serovars as well as antibiotic resistance.


Assuntos
Farmacorresistência Bacteriana Múltipla/genética , Infecções por Escherichia coli/microbiologia , Escherichia coli/genética , Vison/microbiologia , Agricultura , Amicacina/farmacologia , Ampicilina/farmacologia , Animais , Cefoxitina/farmacologia , China , Escherichia coli/isolamento & purificação , Escherichia coli/patogenicidade , Infecções por Escherichia coli/genética , Infecções por Escherichia coli/veterinária , Proteínas de Escherichia coli/genética , Humanos , Testes de Sensibilidade Microbiana , Vison/genética , Tetraciclina/farmacologia
12.
J Dairy Sci ; 102(8): 6920-6922, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31178194

RESUMO

The present study investigated the effects of N-acetylcysteine (NAC) on ß-lactam antibacterial activity against 20 methicillin-resistant Staphylococcus aureus (MRSA) isolates from bovine mastitis. Minimum inhibitory concentrations (MIC) were determined by the E-test method. The presence of 10 mM NAC reduced the MIC of penicillin, ampicillin, oxacillin, cefoxitin, ceftazidime, and cefotaxime to MRSA. Importantly, the MIC of cefoxitin in MRSA in the presence of NAC was lower than the susceptible breakpoint of cefoxitin. The results provide a new way to use current ß-lactam antibiotics combined with NAC against MRSA.


Assuntos
Acetilcisteína/farmacologia , Antibacterianos/farmacologia , Mastite Bovina/microbiologia , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , beta-Lactamas/farmacologia , Acetilcisteína/administração & dosagem , Ampicilina/farmacologia , Animais , Bovinos , Cefoxitina/farmacologia , Feminino , Testes de Sensibilidade Microbiana , Oxacilina/farmacologia , Penicilina G/farmacologia
13.
BMC Res Notes ; 12(1): 337, 2019 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-31196155

RESUMO

OBJECTIVE: To assess the enteric bacteria, methicillin resistant S. aureus and antimicrobial susceptibility patterns from buses surfaces in Mekelle, Tigray, Ethiopia. RESULTS: A total of 300 swab samples were collected from the handle surfaces of the six city buses. The bacterial isolates revealed from the swab samples were E. coli, Enterobacter spp. and S. aureus. The overall positivity rates of E. coli, Enterobacter spp. and S. aureus were 8 (4%), 4 (1.3%) and 54 (18%) respectively. Methicillin resistant S. aureus was seen in 17 (5.7%) of the total 300 swab samples collected and 17 (31.5%) of the S. aureus isolates. All (100%) of the isolates of E. coli and Enterobacter spp. showed resistance for ampicillin and three-fourth of the isolates of E. coli and Enterobacter spp. displayed resistance for chloramphenicol (75%). Five antimicrobials (ampicillin, chloramphenicol, tetracycline, ciprofloxacin, and cotrimoxazole) have showed resistant for one isolate of E. coli. Likewise four antimicrobials (ampicillin, chloramphenicol, ciprofloxacin, and cotrimoxazole) have revealed resistant for one isolate of Enterobacter spp. Moreover, three isolates of S. aureus were also found resistance to four antibiotics.


Assuntos
Antibacterianos/farmacologia , Enterobacteriaceae/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Veículos Automotores , Ampicilina/farmacologia , Cloranfenicol/farmacologia , Ciprofloxacino/farmacologia , Farmacorresistência Bacteriana/efeitos dos fármacos , Enterobacteriaceae/isolamento & purificação , Escherichia coli/isolamento & purificação , Etiópia , Humanos , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Testes de Sensibilidade Microbiana , Tetraciclina/farmacologia , Combinação Trimetoprima e Sulfametoxazol/farmacologia
14.
J Dairy Sci ; 102(8): 6750-6755, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31155256

RESUMO

The use of a sterilized product for washing cows' udders before milking may be useful to reduce or prevent Clostridium tyrobutyricum contamination, the main cause of the late-blowing defect in hard and semi-hard cheeses. The aim of this research was to evaluate the antibacterial efficacy of an experimental formula containing 15% condensed donkey milk (lysozyme content 825 mg/L). The antimicrobial activity of condensed milk was first evaluated in vitro, using the disk diffusion method, on the following microorganisms: Bacillus megaterium, Bacillus mojavensis, Clavibacter michiganensis, and Clostridium tyrobutyricum. These results were compared with the effects of 2 antibiotics, ampicillin (100 mg/mL) and kanamycin (50 mg/ mL), and a commercial pre-dipping formula. The results showed that the inhibitory activity of lysozyme from donkey milk on all the considered microorganisms was higher than that of the commercial product and similar to that of the 2 antibiotics. Next, the formula with lysozyme was compared with a commercial pre-dipping formula on 48 lactating cows (24 cows in each group). Skin tests were performed on teats before and after pre-dipping. Results showed that the formula with condensed milk significantly reduced the clostridial load detected on the skin of cows' teats before cleaning (-55.61% vs. -27.99%) and in the bulk milk of the experimental group compared with the control group with commercial product (-52.53% vs. -32.42%).


Assuntos
Bovinos , Clostridium tyrobutyricum/efeitos dos fármacos , Equidae , Glândulas Mamárias Animais/microbiologia , Leite/enzimologia , Muramidase/farmacologia , Ampicilina/farmacologia , Animais , Anti-Infecciosos/farmacologia , Queijo/microbiologia , Clostridium tyrobutyricum/crescimento & desenvolvimento , Feminino , Canamicina/farmacologia , Lactação
15.
Mater Sci Eng C Mater Biol Appl ; 102: 896-905, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31147061

RESUMO

The development of convenient synthetic methods and improved materials for the production of high load-capacity and biocompatible drug delivery systems is a challenging task with important implications in health sciences. In this work, acrylamide/2-hydroxyethylmethacrylate and N-isopropylacrylamide/2-hydroxyethylmethacrylate hydrogels were synthesized by photopolymerization using energy-efficient green-LEDs. A functionalized silsesquioxane was used as both crosslinker and co-initiator for the photopolymerization. The hybrid organic-inorganic nature of the silsesquioxane improved the resulting hydrogels' properties increasing their swelling capacity and biocompatibility. Additionally, the mild conditions used during the photopolymerization allowed the synthesis of hydrogels in the presence of antibiotics yielding high load-capacity materials in which the drug preserves its molecular structure and antimicrobial activity (as confirmed by HPLC and microbiological assays). The materials were characterized by FTIR, DSC and SEM. Additionally, the kinetics of gels´ swelling and drug release were studied under physiological conditions (pH 7.4 and 37 °C). The results demonstrate how hydrogel composition affects the antibiotics-release kinetics. The final drug release percentage increased with increasing molar fraction of acrylamide or N-isopropylacrylamide and in most cases exceeded 85%. Finally, the antibacterial effect of loaded gels was characterized using a number of assays against Gram negative and Gram positive bacteria. The observed antibacterial effect correlated well with swelling and drug release results. Furthermore, gels are not toxic for isolated erythrocytes as demonstrated by haemolytic tests. Overall, our results indicate that the produced hydrogels are promising materials to develop controlled drug-delivery devices such as capsules, dermatological patches and others.


Assuntos
Antibacterianos/farmacologia , Hidrogéis/química , Polimerização , Acrilamidas/química , Ampicilina/farmacologia , Preparações de Ação Retardada/farmacologia , Liberação Controlada de Fármacos , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Gentamicinas/farmacologia , Hemólise/efeitos dos fármacos , Humanos , Hidrogéis/síntese química , Cinética , Metacrilatos/química , Testes de Sensibilidade Microbiana , Espectroscopia de Infravermelho com Transformada de Fourier , Staphylococcus aureus/efeitos dos fármacos , Água
16.
Biomater Sci ; 7(9): 3788-3794, 2019 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-31218306

RESUMO

Photodynamic therapy (PDT) has been reported to be an effective alternative to combat bacterial infections even those triggered by drug-resistant strains as there is little chance to develop resistance to this therapy. Therefore, it is imperative to design and synthesize a superior photo-active bactericide for the treatment of bacterial infections. Herein, we synthesized three bactericidal activity-tunable conjugated polymers (P1-P3) with various photoactive capabilities and employed them for the treatment of wound infections with little damage to cells; by altering the construction unit of π-conjugated backbone structures with electron-rich and electron-deficient aromatic heterocycles, the optical properties and ability of reactive oxygen species (ROS) generation could be regulated; this resulted in a tunable killing ability. The cationic quaternary ammonium (QA) groups on the side chains endowed the CPs with not only good dispersibility but also a better interaction with the negatively charged membrane of bacteria. The antibacterial experiments towards ampicillin-resistant Escherichia coli TOP10 (E. coli) and the treatment of wound infections in mice indicate that the P1-P3 have varied bactericidal activities; moreover, P3 has been demonstrated to be a human-friendly bactericide with excellent antibacterial capability. It not only acts as a potential bactericide for the practical treatment of infectious wounds, but also offers guidance for the design and structure control of photo-active bactericides.


Assuntos
Ampicilina/farmacologia , Antibacterianos/farmacologia , Escherichia coli/efeitos dos fármacos , Polímeros/farmacologia , Compostos de Amônio Quaternário/farmacologia , Infecção dos Ferimentos/tratamento farmacológico , Ampicilina/química , Antibacterianos/química , Farmacorresistência Bacteriana/efeitos dos fármacos , Humanos , Testes de Sensibilidade Microbiana , Fotoquimioterapia , Polímeros/química , Compostos de Amônio Quaternário/química
17.
BMC Infect Dis ; 19(1): 420, 2019 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-31088380

RESUMO

BACKGROUND: Urinary tract infection is an infection affecting infants and children. The aim of this study was to determine the etiology of urinary tract infection along with their antimicrobial resistance. METHODS: This cross-sectional study was conducted from June 2015 to January 2016 at Siddhi Memorial Hospital, Bhaktapur, Nepal. Urine samples were first cultured on cystine lactose electrolyte deficient agar and blood agar by semi-quantitative technique, and then incubated aerobically for 18-24 h at 37 °C. The identified bacterial isolates were tested for antimicrobial susceptibility by Kirby Bauer disc diffusion technique. RESULTS: Of 1599 urine samples, 12.3% samples showed significant bacterial growth. E. coli (58.7%) was the most common pathogen, followed by Klebsiella pneumoniae (22.5%). Most of the isolates were resistant to ampicillin and co-trimoxazole, while least were resistant to amikacin and nitrofurantoin. Higher multi-drug resistance (61.9%) was observed among isolates. CONCLUSIONS: E. coli and Klebsiella spp. were predominant cause of pediatric urinary tract infection in children. Higher susceptibility observed against aminoglycosides and nitrofurans make these drugs suitable in emergency.


Assuntos
Farmacorresistência Bacteriana , Infecções Urinárias/diagnóstico , Adolescente , Ampicilina/farmacologia , Ampicilina/uso terapêutico , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Criança , Pré-Escolar , Estudos Transversais , Farmacorresistência Bacteriana/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Escherichia coli/isolamento & purificação , Feminino , Hospitais Pediátricos , Humanos , Lactente , Recém-Nascido , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/isolamento & purificação , Masculino , Testes de Sensibilidade Microbiana , Nepal/epidemiologia , Combinação Trimetoprima e Sulfametoxazol/farmacologia , Combinação Trimetoprima e Sulfametoxazol/uso terapêutico , Infecções Urinárias/epidemiologia , Infecções Urinárias/microbiologia
18.
Ann Clin Microbiol Antimicrob ; 18(1): 16, 2019 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-31060558

RESUMO

BACKGROUND: Invasive meningococcal disease (IMD) persists in military units in Vietnam despite the availability of antibiotics and vaccines. A hindrance to reducing the incidence of IMD in Vietnam is a lack of molecular data from isolates of the causative agent, Neisseria meningitidis from this country. Here, we characterized key genetic and epidemiological features of an invasive N. meningitidis isolate from a military unit in Vietnam using whole-genome sequencing. METHODS: Neisseria meningitidis was isolated from a conscript admitted for meningitis and tested against seven antibiotics. DNA from the isolate was extracted and sequenced using the Illumina HiSeq platform. Denovo assembly and scaffolding were performed to construct a draft genome assembly, from which genes were predicted and functionally annotated. Genome analysis included epidemiological characterization, genomic composition and identification of antibiotic resistance genes. RESULTS: Susceptibility testing of the isolate showed high levels of resistance to chloramphenicol and diminished susceptibility to ampicillin and rifampicin. A draft genome of ~ 2.1 Mb was assembled, containing 2451 protein coding sequences, 49 tRNAs and 3 rRNAs. Fifteen coding sequences sharing ≥ 84% identity with known antibiotic resistance genes were identified. Genome analysis revealed abundant repetitive DNAs and two prophages. Epidemiological typing revealed newly described sequence type, antigenic finetype and Bexsero® Antigen Sequence Typing (BAST). The BAST profile showed no coverage by either Bexsero® or Trumenba®. CONCLUSIONS: Our results present the first genome assembly of an invasive N. meningitidis isolate from a military unit in Vietnam. This study illustrates the usefulness of whole genome sequencing (WGS) analysis for epidemiological and antibiotic resistance studies and surveillance of IMD in Vietnam.


Assuntos
Antibacterianos/farmacologia , Genoma Bacteriano , Infecções Meningocócicas/microbiologia , Neisseria meningitidis/efeitos dos fármacos , Neisseria meningitidis/enzimologia , Ampicilina/farmacologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Farmacorresistência Bacteriana , Humanos , Masculino , Militares , Neisseria meningitidis/isolamento & purificação , Rifampina/farmacologia , Vietnã , Sequenciamento Completo do Genoma , Adulto Jovem
19.
Pak J Pharm Sci ; 32(2): 477-481, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31081755

RESUMO

The aim of this study was to determine efficiency of a new molecule that was obtained by linking boric acid with ampicillin in treating intra-abdominal infection.Following intraperitoneal E. coli injection totwenty-one female Wistar albino rats, group 1 was administered boron-linked ampicillin, group 2 was administered only ampicillin and group 3 was injected intraperitoneally with physiological serum. IL-6, and a white blood cell analysis was performed from the blood before and on the seventh day of treatment.No statistically significant difference in blood WBC levels after treatment was found among the groups. There was no statistically significant difference in the IL-6 values of group 2 and group 3 before and after the treatment (p=0.195 and 0.193, respectively); however, the reduction in the serum IL-6 values of group 1 was statistically significant (p=0.003).Boric acid-linked ampicillin is a more effective intra-abdominal infection treatment compared with ampicillin alone.


Assuntos
Ampicilina/farmacologia , Antibacterianos/farmacologia , Ácidos Bóricos/farmacologia , Sepse/tratamento farmacológico , Abdome , Ampicilina/química , Animais , Antibacterianos/química , Ácidos Bóricos/química , Modelos Animais de Doenças , Feminino , Interleucina-6/sangue , Ratos Wistar , Sepse/sangue , Sepse/mortalidade
20.
Int J Biol Macromol ; 133: 148-155, 2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-30991065

RESUMO

A novel BG composite sponge comprising of bacterial cellulose (BC) and gelatin has been synthesized using glutaraldehyde as the cross-linker by a facile method. The morphology, chemical composition and structures of the novel sponges were characterized by SEM, EDS and FTIR spectroscopy. The fabricated BG sponges have regular honeycomb-like structure with uniform pore distribution and large surface area. They have very high porosity of 94%-95% and great swelling property ranging from 3000 to 3150%. Moreover, the released rate of the model drug ampicillin (AP) from the composite sponges depends on the initial addition of AP that the diffusional constant (n) determined using Korsmeyer-Peppas model lies between 0.45 and 0.89, indicating the AP release from BG composite sponges follows non-Fickian diffusion. More interestingly, antibacterial activity of BG sponges was investigated by diffusion disk method against E.coli, C. albicans and S. aureus. The results demonstrated that the obtained BG sponges exhibit excellent antibacterial activity, thus making them have great potentials in various antibacterial applications, especially in the wound dressings.


Assuntos
Anti-Infecciosos/química , Bandagens/microbiologia , Celulose/química , Portadores de Fármacos/química , Gelatina/química , Gluconacetobacter xylinus/química , Ampicilina/química , Ampicilina/farmacologia , Liberação Controlada de Fármacos , Células HEK293 , Humanos , Porosidade , Cicatrização/efeitos dos fármacos
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