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1.
PLoS One ; 15(8): e0236713, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32750089

RESUMO

Coagulase-negative staphylococci (CoNS) are the most common isolates from blood culture in neonates resulting in high mortality and morbidity. This study investigated CoNS obtained from blood cultures of neonates for antibiotic resistance and virulence factors, and possible association with inflammatory response (C-reactive protein). A total of 93 CoNS isolates were collected from 76 blood cultures of neonates at the Maternity hospital in Kuwait in a six-month period and investigated for susceptibility to antibiotics, carriage of staphylococcal cassette chromosome mec (SCCmec), and virulence-associated genes. The 93 CoNS isolates consisted of S. epidermidis (76; 81.7%), S. capitis (12; 12.9%), S. hominis (2; 2.1%), S. warneri (2; 2.1%) and S. haemolyticus (1; 1.0%). Eighty-six (92.4%) of the isolates were resistant to cefoxitin (MR-CoNS) while 49 (52.7%) expressed multi-antibiotic resistance. The methicillin-resistant isolates (MR-CoNS) carried SCCmec III, SCCmec IVa and four combinations of SCCmec types including SCCmec types I+IVa (one S. warneri and 25 S. epidermidis isolates), types I+III (one S. epidermidis isolate), types III+IVa (six S. epidermidis isolates) and types I+III+IVa (one S. epidermidis isolate). The most common virulence-related genes were icaC, seb, arc detected in 69.7%, 60.5%, 40.8% of the isolates respectively. Two isolates were positive for tst1. No association between C-reactive protein and antibiotic resistance or virulence factors was established. This study revealed that S. epidermidis carrying different SCCmec genetic elements, was the dominant CoNS species isolated from neonatal blood cultures with 90.3% and 36.6% of the isolates positive for genes for biofilm and ACME production respectively.


Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana , Recém-Nascido Prematuro , Infecções Estafilocócicas/microbiologia , Staphylococcus/efeitos dos fármacos , Toxinas Bacterianas/genética , Biofilmes , Coagulase/metabolismo , Feminino , Genes Bacterianos , Humanos , Recém-Nascido , Kuweit , Masculino , Testes de Sensibilidade Microbiana , Estudos Retrospectivos , Staphylococcus/enzimologia , Staphylococcus/isolamento & purificação , Staphylococcus/metabolismo , Fatores de Virulência/genética , Fatores de Virulência/metabolismo
2.
Proc Natl Acad Sci U S A ; 117(33): 19953-19962, 2020 08 18.
Artigo em Inglês | MEDLINE | ID: mdl-32737158

RESUMO

Protein conformational changes associated with ligand binding, especially those involving intrinsically disordered proteins, are mediated by tightly coupled intra- and intermolecular events. Such reactions are often discussed in terms of two limiting kinetic mechanisms, conformational selection (CS), where folding precedes binding, and induced fit (IF), where binding precedes folding. It has been shown that coupled folding/binding reactions can proceed along both CS and IF pathways with the flux ratio depending on conditions such as ligand concentration. However, the structural and energetic basis of such complex reactions remains poorly understood. Therefore, we used experimental, theoretical, and computational approaches to explore structural and energetic aspects of the coupled-folding/binding reaction of staphylococcal nuclease in the presence of the substrate analog adenosine-3',5'-diphosphate. Optically monitored equilibrium and kinetic data, combined with a statistical mechanical model, gave deeper insight into the relative importance of specific and Coulombic protein-ligand interactions in governing the reaction mechanism. We also investigated structural aspects of the reaction at the residue level using NMR and all-atom replica-permutation molecular dynamics simulations. Both approaches yielded clear evidence for accumulation of a transient protein-ligand encounter complex early in the reaction under IF-dominant conditions. Quantitative analysis of the equilibrium/kinetic folding revealed that the ligand-dependent CS-to-IF shift resulted from stabilization of the compact transition state primarily by weakly ligand-dependent Coulombic interactions with smaller contributions from specific binding energies. At a more macroscopic level, the CS-to-IF shift was represented as a displacement of the reaction "route" on the free energy surface, which was consistent with a flux analysis.


Assuntos
Proteínas de Bactérias/química , Desoxirribonucleases/química , Staphylococcus/enzimologia , Proteínas de Bactérias/metabolismo , Desoxirribonucleases/metabolismo , Cinética , Ligantes , Simulação de Dinâmica Molecular , Staphylococcus/química
3.
BMC Infect Dis ; 20(1): 539, 2020 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-32703263

RESUMO

BACKGROUND: Staphylococcus saccharolyticus is a rarely encountered coagulase-negative, which grows slowly and its strictly anaerobic staphylococcus from the skin. It is usually considered a contaminant, but some rare reports have described deep-seated infections. Virulence factors remain poorly known, although, genomic analysis highlights pathogenic potential. CASE PRESENTATION: We report a case of Staphylococcus saccharolyticus spondylodiscitis that followed kyphoplasty, a procedure associated with a low rate but possible severe infectious complication (0.46%), and have reviewed the literature. This case specifically stresses the risk of healthcare-associated S. saccharolyticus infection in high-risk patients (those with a history of alcoholism and heavy smoking). CONCLUSION: S. saccharolyticus infection is difficult to diagnose due to microbiological characteristics of this bacterium; it requires timely treatment, and improved infection control procedure should be encouraged for high-risk patients.


Assuntos
Infecção Hospitalar/diagnóstico , Discite/diagnóstico por imagem , Cifoplastia/efeitos adversos , Complicações Pós-Operatórias/diagnóstico , Infecções Estafilocócicas/diagnóstico , Staphylococcus/isolamento & purificação , Vértebras Torácicas/microbiologia , Amoxicilina/administração & dosagem , Amoxicilina/uso terapêutico , Antibacterianos/administração & dosagem , Antibacterianos/uso terapêutico , Coagulase/metabolismo , Infecção Hospitalar/tratamento farmacológico , Infecção Hospitalar/microbiologia , Discite/tratamento farmacológico , Discite/microbiologia , Humanos , Imagem por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias/tratamento farmacológico , Complicações Pós-Operatórias/microbiologia , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/microbiologia , Staphylococcus/enzimologia , Vértebras Torácicas/diagnóstico por imagem , Resultado do Tratamento
4.
Curr Pharm Biotechnol ; 21(12): 1140-1153, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32324510

RESUMO

Coagulase-negative staphylococci (CoNS) are part of the microbiota of human skin and rarely linked with soft tissue infections. In recent years, CoNS species considered as one of the major nosocomial pathogens and can cause several infections such as catheter-acquired sepsis, skin infection, urinary tract infection, endophthalmitis, central nervous system shunt infection, surgical site infections, and foreign body infection. These microorganisms have a significant impact on human life and health and, as typical opportunists, cause peritonitis in individuals undergoing peritoneal dialysis. Moreover, it is revealed that these potential pathogens are mainly related to the use of indwelling or implanted in a foreign body and cause infective endocarditis (both native valve endocarditis and prosthetic valve endocarditis) in patients. In general, approximately eight percent of all cases of native valve endocarditis is associated with CoNS species, and these organisms cause death in 25% of all native valve endocarditis cases. Moreover, it is revealed that methicillin-resistant CoNS species cause 60 % of all prosthetic valve endocarditis cases. In this review, we describe the role of the CoNS species in infective endocarditis, and we explicated the reported cases of CoNS infective endocarditis in the literature from 2000 to 2020 to determine the role of CoNS in the process of infective endocarditis.


Assuntos
Antibacterianos/uso terapêutico , Coagulase/metabolismo , Endocardite/microbiologia , Infecções Estafilocócicas/microbiologia , Staphylococcus/patogenicidade , Endocardite/tratamento farmacológico , Endocardite/epidemiologia , Próteses Valvulares Cardíacas/microbiologia , Valvas Cardíacas/microbiologia , Humanos , Masculino , Pessoa de Meia-Idade , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/epidemiologia , Staphylococcus/enzimologia
5.
PLoS Biol ; 18(3): e3000686, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32226015

RESUMO

Compact CRISPR/Cas9 systems that can be packaged into an adeno-associated virus (AAV) hold great promise for gene therapy. Unfortunately, currently available small Cas9 nucleases either display low activity or require a long protospacer adjacent motif (PAM) sequence, limiting their extensive applications. Here, we screened a panel of Cas9 nucleases and identified a small Cas9 ortholog from Staphylococcus auricularis (SauriCas9), which recognizes a simple NNGG PAM, displays high activity for genome editing, and is compact enough to be packaged into an AAV for genome editing. Moreover, the conversion of adenine and cytosine bases can be achieved by fusing SauriCas9 to the cytidine and adenine deaminase. Therefore, SauriCas9 holds great potential for both basic research and clinical applications.


Assuntos
Proteína 9 Associada à CRISPR/metabolismo , DNA/metabolismo , Edição de Genes/métodos , Staphylococcus/enzimologia , Sequência de Aminoácidos , Proteína 9 Associada à CRISPR/química , Proteína 9 Associada à CRISPR/genética , Sistemas CRISPR-Cas , DNA/química , DNA/genética , Dependovirus/genética , Células HEK293 , Humanos , Motivos de Nucleotídeos , Engenharia de Proteínas , Staphylococcus/genética , Especificidade por Substrato
6.
Biomed Pharmacother ; 123: 109779, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31918211

RESUMO

Staphylococcus xylosus (S. xylosus) is one of the emerging pathogens causing bovine mastitis with high rate of isolation in most of the reported clinical and field cases. To verify the role of glutamine synthetase (GS) in the pathogenesis of S. xylosus, we evaluated the virulence level of the wild-type strain and its glnA mutant strain in biofilm assays in vitro and murine infection model in vivo. From the results, it was observed that the glnA mutant strain was attenuated and could reduce tissue damage. 1-Hydroxyanthraquinone (1-HAQ) is a kind of anthraquinones, it exhibited a significant inhibitory effect on the growth of S. xylosus and biofilm formation in vitro and provided anti-inflammatory effects in vivo. In addition, the rate at which it inhibits the biofilm, inflammatory factors, and CFU of wild-type strains were significantly higher than that of the mutant strains, indicating that 1-hAQ might have pharmacological effects against S. xylosus through the regulation of GS protein. The effect of 1-hAQ on GS was further confirmed by the down-regulation of glnA expression, reduced GS activity, Gln content and the results of molecular docking. Taken together, these findings suggest that 1-hAQ facilitated a significant attenuation of S. xylosus pathogenicity by regulating the GS protein: a vital virulence factor. Therefore, it can be inferred that 1-hAQ may serve as a potential source of organic compound for the development of novel alternative drugs in mitigating the menace of bovine mastitis.


Assuntos
Antraquinonas/farmacologia , Antibacterianos/farmacologia , Glutamato-Amônia Ligase/metabolismo , Staphylococcus/enzimologia , Staphylococcus/patogenicidade , Fatores de Virulência/metabolismo , Animais , Antraquinonas/química , Antraquinonas/uso terapêutico , Antibacterianos/uso terapêutico , Biofilmes/efeitos dos fármacos , Contagem de Colônia Microbiana , Modelos Animais de Doenças , Feminino , Mastite/tratamento farmacológico , Mastite/microbiologia , Mastite/patologia , Camundongos Endogâmicos BALB C , Testes de Sensibilidade Microbiana , Simulação de Acoplamento Molecular , Staphylococcus/efeitos dos fármacos , Staphylococcus/crescimento & desenvolvimento
7.
Clin Microbiol Infect ; 26(1): 122.e1-122.e6, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31108230

RESUMO

OBJECTIVES: Until recently, the European Committee on Antimicrobial Susceptibility Testing (EUCAST) recommended the cefoxitin disc to screen for mecA-mediated ß-lactam resistance in Staphylococcus pseudintermedius. A recent study indicated that cefoxitin was inferior to oxacillin in this respect. We have re-evaluated cefoxitin and oxacillin discs for screening for methicillin resistance in S. pseudintermedius. METHODS: We included 224 animal and human S. pseudintermedius isolates from Europe (n = 108) and North America (n = 116), of which 109 were mecA-positive. Disc diffusion was performed per EUCAST recommendations using 30-µg cefoxitin and 1-µg oxacillin discs from three manufacturers and Mueller-Hinton agar from two manufacturers. RESULTS: Cefoxitin inhibition zones ranged from 6 to 33 mm for mecA-positive S. pseudintermedius (MRSP) and from 29 to 41 mm for mecA-negative S. pseudintermedius (MSSP). The corresponding oxacillin zone intervals were 6-20 mm and 19-30 mm. For cefoxitin 16% (95% CI 14.8-18.0%) of the isolates were in the area where positive and negative results overlapped. For oxacillin the corresponding number was 2% (1.6-2.9%). For oxacillin a breakpoint of susceptible (S) ≥ 20 mm and resistant (R) <20 mm resulted in only 0.4% and 1.1% very major error and major error rates respectively. CONCLUSIONS: This investigation confirms that the 1-µg oxacillin disc predicts mecA-mediated methicillin resistance in S. pseudintermedius better than the 30-µg cefoxitin disc. For a 1-µg oxacillin disc we propose that 20 mm should be used as cut off for resistance, i.e. isolates with a zone diameter <20 mm are resistant to all ß-lactam antibiotics except those with activity against methicillin-resistant staphylococci.


Assuntos
Antibacterianos/farmacologia , Proteínas de Bactérias/metabolismo , Cefoxitina/farmacologia , Testes de Sensibilidade a Antimicrobianos por Disco-Difusão/métodos , Oxacilina/farmacologia , Staphylococcus/efeitos dos fármacos , Resistência beta-Lactâmica , Animais , Proteínas de Bactérias/genética , Testes de Sensibilidade a Antimicrobianos por Disco-Difusão/normas , Humanos , Testes de Sensibilidade Microbiana , Infecções Estafilocócicas/microbiologia , Staphylococcus/enzimologia
8.
Int J Food Microbiol ; 315: 108419, 2020 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-31734616

RESUMO

The effects of glucose and sucrose on the gene expression of nitric oxide synthase (NOS) in Staphylococcus vitulinus and colour formation in dry sausages were investigated. The results showed that sucrose addition promoted nitric oxide (NO) production in media when compared with glucose. In addition, sucrose could up-regulate nos (encoding NOS) and katA (encoding catalase KatA) gene expression by enhancing oxidative stress levels. In the sausages inoculated with S. vitulinus, a*-values (indicating redness) of the sausages with added sucrose were higher than those of samples with added glucose (P < 0.05) but did not differ from those in the nitrite treatment group (P > 0.05). The UV-vis spectra results showed that nitrosylmyoglobin (NO-Mb) was formed in the sausages with either S. vitulinus or nitrite added. In the S. vitulinus-inoculated sausages, sucrose addition led to a higher NO-Mb content than that after glucose addition, which was attributed to up-regulation of the nos gene. This study provides a potential method to enhance NO yield in S. vitulinus and colour formation in dry sausages without nitrite addition.


Assuntos
Catalase/biossíntese , Glucose/metabolismo , Óxido Nítrico Sintase/biossíntese , Staphylococcus/metabolismo , Sacarose/metabolismo , Animais , Catalase/genética , Cor , Produtos da Carne/análise , Mioglobina/biossíntese , Óxido Nítrico/biossíntese , Óxido Nítrico Sintase/genética , Nitritos/metabolismo , Oxirredução , Estresse Oxidativo/efeitos dos fármacos , Staphylococcus/enzimologia , Staphylococcus/genética , Ativação Transcricional , Regulação para Cima
9.
PLoS One ; 14(12): e0226260, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31860659

RESUMO

Staphylococcus xylosus (S. xylosus) is a type of coagulase-negative Staphylococcus, which was previously considered as non-pathogenic. However, recent studies have linked it with cases of mastitis in cows. Isoliquiritigenin (ISL) is a bioactive compound with pharmacological functions including antibacterial activity. In this study, we evaluated the effect of ISL on S. xylosus in vitro and in vivo. The MIC of ISL against S. xylosus was 80 µg/mL. It was observed that sub-MICs of ISL (1/2MIC, 1/4MIC, 1/8MIC) significantly inhibited the formation of S. xylosus biofilm in vitro. Previous studies have observed that inhibiting imidazole glycerol phosphate dehydratase (IGPD) concomitantly inhibited biofilm formation in S. xylosus. So, we designed experiments to target the formation of IGPD or inhibits its activities in S. xylosus ATCC 700404. The results indicated that the activity of IGPD and its histidine content decreased significantly under 1/2 MIC (40 µg/mL) ISL, and the expression of IGPD gene (hisB) and IGPD protein was significantly down-regulated. Furthermore, Bio-layer interferometry experiments showed that ISL directly interacted with IGPD protein (with strong affinity; KD = 234 µM). In addition, molecular docking was used to predict the binding mode of ISL and IGPD. In vivo tests revealed that, ISL significantly reduced TNF-α and IL-6 levels, mitigated the destruction of the mammary glands and reversed the production of inflammatory cells in mice. The results of the study suggest that, ISL may inhibit S. xylosus growth by acting on IGPD, which can be used as a target protein to treat infections caused by S. xylosus.


Assuntos
Chalconas/administração & dosagem , Hidroliases/antagonistas & inibidores , Mastite/tratamento farmacológico , Infecções Estafilocócicas/tratamento farmacológico , Staphylococcus/efeitos dos fármacos , Animais , Proteínas de Bactérias/antagonistas & inibidores , Proteínas de Bactérias/química , Biofilmes/efeitos dos fármacos , Chalconas/química , Chalconas/farmacologia , Modelos Animais de Doenças , Regulação para Baixo , Feminino , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Hidroliases/química , Camundongos , Testes de Sensibilidade Microbiana , Modelos Moleculares , Simulação de Acoplamento Molecular , Staphylococcus/enzimologia , Staphylococcus/crescimento & desenvolvimento
10.
Pan Afr Med J ; 33: 193, 2019.
Artigo em Francês | MEDLINE | ID: mdl-31692677

RESUMO

Introduction: Blood cultures are the best diagnostic tool for the detection of bacteremia. However, false positive results may lead to confusion about antibiotic regimens, putting the lives of patients at risk. The main purpose of this study was to assess the prevalence of coagulase negative Staphylococci (CoNS) as well as of Corynebacterium spp and Bacillus spp in the bags of blood culture analyzed in the microbiology laboratory at the Ibn-Rochd University Hospital in Casablanca. This prevalence was evaluated according to various Hospital Departments over the year 2016. Methods: We conducted a descriptive, retrospective study by analysing the computerized database of the Laboratory of bacteriology and virology at the Ibn-Rochd University Hospital in Casablanca over a 12-month period from 1st January to 31st December 2016. Our study focused on bacteria forming part of the commensal flora (coagulase negative Staphylococcus, Corynebacteria spp and Bacillus spp). The blood culture bags were incubated in the automated blood culture system (Bactec FX). The identification of the germs from a positive culture was performed according to the standard techniques of bacteriology and susceptibility testing was performed according to EUCAST 2015. We conducted an analysis of the computerized database of KALISIL system (Netika) version (2.2.10.) of the Microbiology Laboratory at the Ibn-Rochd University Hospital in Casablanca. Results: Out of 7959 requests for blood cultures obtained from 5801 patients addressed to the laboratory of bacteriology, 2491 were positive, of which 848, reflecting a rate of 34% of positive bags or 10.6% of the whole of bags received over the year 2016, were positive for coagulase negative Staphylococcus, 56 bags of blood cultures, reflecting a rate of 2.2%, were positive for Corrynébacteruim SP, followed by 60 bags of blood cultures, reflecting a rate of 2.4%, which were positive for Bacillus sp. The frequency of isolation of coagulase negative Staphylococcus compared to other bacteria according to Clinical Departments showed a higher frequency in the Paediatric Department (47.2%) followed by the Medicine Department (44.1%). Conclusion: This study shows that coagulase negative Staphylococci are the organisms most frequently isolated from blood cultures. They are a non-negligible cause of nosocomial infections, but they are also the most common blood culture contaminants.


Assuntos
Bacteriemia/epidemiologia , Infecções Estafilocócicas/epidemiologia , Staphylococcus/isolamento & purificação , Bacteriemia/diagnóstico , Bacteriemia/microbiologia , Hemocultura , Coagulase , Infecção Hospitalar/diagnóstico , Infecção Hospitalar/epidemiologia , Infecção Hospitalar/microbiologia , Hospitais Universitários , Humanos , Marrocos/epidemiologia , Prevalência , Estudos Retrospectivos , Infecções Estafilocócicas/diagnóstico , Infecções Estafilocócicas/microbiologia , Staphylococcus/enzimologia
11.
Biomedica ; 39(3): 513-523, 2019 09 01.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-31584765

RESUMO

Introduction: Infections associated with health care caused by S. aureus and coagulase-negative Staphylococci multi-resistant to antibiotics cause a high epidemiological impact due to their high morbidity and mortality. Biofilm formation, which has been associated with antimicrobial resistance, can also occur. Objectives: To determine methicillin resistance and to quantify the biofilm production to establish if there is a relationship in clinical isolates of S. aureus and coagulase-negative Staphylococci. Material and methods: A total of 11 strains of S. aureus and 12 of coagulase-negative Staphylococci were studied. Methicillin resistance was determined with cefoxitin discs and the Clinical Laboratory Standards Institute (CSLI), 2018 reference values. Biofilm production was quantified by the crystal violet method. The mecA and icaADBC genes were identified by PCR. A bivariate analysis was performed with chi-square (c2) and Cramér's V statistical tests, using SPSS™, version 20.0 software. Results: Nine S. aureus strains were methicillin-resistant and two were sensitive. Eight coagulase-negative Staphylococci strains were resistant and four were sensitive. The mecA genotype was found in eight of the nine S. aureus resistant strains and six of eight resistant coagulase-negative Staphylococci. All strains formed biofilms. Ten strains of S. aureus and 11 of coagulase-negative Staphylococci presented the icaADCB genotype. No association was found between methicillin-resistance and biofilm formation. Conclusions: Cefoxitin is enough to define the resistance phenotype and is associated with the mecA genotype. All strains formed biofilms and were related to the presence of the icaADCB operon. Biofilm formation and methicillin resistance were independent features in both groups of strains.


Assuntos
Biofilmes/crescimento & desenvolvimento , Resistência a Meticilina , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/fisiologia , Staphylococcus/efeitos dos fármacos , Staphylococcus/fisiologia , Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Cefoxitina/farmacologia , Coagulase , DNA Bacteriano/isolamento & purificação , Genes Bacterianos , Humanos , Resistência a Meticilina/genética , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/genética , México , Testes de Sensibilidade Microbiana/métodos , Oxacilina/farmacologia , Proteínas de Ligação às Penicilinas/genética , Infecções Estafilocócicas/microbiologia , Staphylococcus/enzimologia , Staphylococcus/genética , Staphylococcus aureus/genética
12.
Biomed Res Int ; 2019: 2165316, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31534954

RESUMO

The aim of this study was to determine the species distribution of Staphylococcus, Gram negative bacteria (GNB) and the occurrence of Methicillin Resistant Staphylococci (MRS) and Extended-Spectrum ß-lactamase- (ESBL-) producing GNB. Bacterial culture of 300 clinical mastitis milk samples from 30 different farms across different regions of Tunisia during four seasons was realized. The obtained results showed the presence of high frequency of the tested samples with a positive growth for bacteria (64%). In addition a high recovery rate of Staphylococci and/or GNB in these clinical mastitis milk samples (87%) was detected. In addition, a high percentage of GNB (68.2%) compared to Staphylococcus species (32%) was noted. Moreover, a significant variation of the number of these bacteria according to the farm location, the seasons, and cows age was detected. The highest percentage was observed in the North of Tunisia during the winter and the spring seasons in adult cows with a dominance of GNB growth. Coagulase negative Staphylococci (CNS) (n=11) and GNB (n=16) species were identified. Escherichia coli (E. coli) was the most frequently found bacterium followed by Klebsiella pneumoniae. The dominant Staphylococcus isolates was S. xylosus followed by S. aureus the major pathogen isolated. Methicillin resistance was confirmed by the presence of the mecA gene in 3 S. aureus and 14 CNS isolates; all of these isolates were lacking the mecC gene. Various species of GNB, resistant to cefotaxime, were detected (n=15). ESBLs were detected on selective medium in 10 E. coli and 4 K. pneumoniae. All ESBL producers strains carry the blaCTX-M. The presence of different resistant mastitis pathogens in dairy farms may complicate therapeutic options and contaminated animals could become zoonotic agent reservoir for human.


Assuntos
Proteínas de Bactérias/genética , Bactérias Gram-Negativas , Infecções por Bactérias Gram-Negativas , Mastite Bovina , Infecções Estafilocócicas , Staphylococcus , beta-Lactamases/genética , Animais , Bovinos , Feminino , Bactérias Gram-Negativas/enzimologia , Bactérias Gram-Negativas/genética , Infecções por Bactérias Gram-Negativas/enzimologia , Infecções por Bactérias Gram-Negativas/epidemiologia , Infecções por Bactérias Gram-Negativas/genética , Mastite Bovina/enzimologia , Mastite Bovina/epidemiologia , Mastite Bovina/genética , Mastite Bovina/microbiologia , Infecções Estafilocócicas/enzimologia , Infecções Estafilocócicas/epidemiologia , Infecções Estafilocócicas/genética , Staphylococcus/enzimologia , Staphylococcus/genética , Tunísia/epidemiologia
13.
Molecules ; 24(17)2019 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-31480403

RESUMO

Thermostability remains one of the most desirable traits in many lipases. Numerous studies have revealed promising strategies to improve thermostability and random mutagenesis often leads to unexpected yet interesting findings in engineering stability. Previously, the thermostability of C-terminal truncated cold-adapted lipase from Staphylococcus epidermidis AT2 (rT-M386) was markedly enhanced by directed evolution. The newly evolved mutant, G210C, demonstrated an optimal temperature shift from 25 to 45 °C and stability up to 50 °C. Interestingly, a cysteine residue was randomly introduced on the loop connecting the two lids and accounted for the only cysteine found in the lipase. We further investigated the structural and mechanistic insights that could possibly cause the significant temperature shift. Both rT-M386 and G210C were modeled and simulated at 25 °C and 50 °C. The results clearly portrayed the effect of cysteine substitution primarily on the lid stability. Comparative molecular dynamics simulation analysis revealed that G210C exhibited greater stability than the wild-type at high temperature simulation. The compactness of the G210C lipase structure increased at 50 °C and resulted in enhanced rigidity hence stability. This observation is supported by the improved and stronger non-covalent interactions formed in the protein structure. Our findings suggest that the introduction of a single cysteine residue at the lid region of cold-adapted lipase may result in unexpected increased in thermostability, thus this approach could serve as one of the thermostabilization strategies in engineering lipase stability.


Assuntos
Temperatura Baixa , Cisteína/genética , Glicina/genética , Lipase/genética , Mutação/genética , Staphylococcus/enzimologia , Cátions , Estabilidade Enzimática , Ligação de Hidrogênio , Lipase/química , Modelos Moleculares , Simulação de Dinâmica Molecular , Proteínas Mutantes/metabolismo , Sais/química , Solventes
14.
Rev. esp. quimioter ; 32(supl.3): 24-28, sept. 2019. tab
Artigo em Inglês | IBECS | ID: ibc-188975

RESUMO

Ceftobiprole is a new cephalosporin with an extended spectrum activity against the majority of microorganisms isolated in bacteremia including methicillin-susceptible (MSSA) and -resistant S. aureus (MRSA). This antibiotic has demonstrated a potent activity against MRSA in animal models of endocarditis in monotherapy but particularly in combination with daptomycin, suggesting that this combination could be a future option to improve the outcome of staphylococcal endovascular infections. In addition, the extended-spectrum ceftobiprole activity, including coagulase-negative staphylococci, Enterococcus faecalis, Enterobacteriaceae and Pseudomonas aeruginosa represents an advantage for use as empirical therapy in bacteremia potentially caused by a broad spectrum of microorganisms, such as in catheter-related bacteremia


No disponible


Assuntos
Humanos , Antibacterianos/uso terapêutico , Bacteriemia/tratamento farmacológico , Cefalosporinas/uso terapêutico , Infecções Estafilocócicas/tratamento farmacológico , Bacteriemia/microbiologia , Daptomicina/uso terapêutico , Pseudomonas aeruginosa/efeitos dos fármacos , Infecções Estafilocócicas/microbiologia , Quimioterapia Combinada/métodos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus/efeitos dos fármacos , Staphylococcus/enzimologia , Staphylococcus aureus/efeitos dos fármacos
15.
Infect Dis (Lond) ; 51(9): 683-690, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31389725

RESUMO

Background: Periprosthetic joint infection (PJI) caused by coagulase-negative staphylococci (CoNS) is increasingly common and is sometimes treated with off-label use of linezolid. Methods: We conducted a retrospective study of patients with PJI caused by CoNS treated with surgical intervention and orally administrated linezolid during the period 1995-2014 (n = 28). Clinical outcomes and adverse events related to linezolid administration were evaluated. Mean time to follow-up was 4.3 years (range: 0.2-12). Results: Twenty-two of 28 patients were infection-free at follow-up. No CoNS strain was resistant to vancomycin, but 16 of 28 were resistant to rifampicin, 23 of 28 to clindamycin and 20 of 27 to quinolones. The mean duration of linezolid treatment was 4.2 weeks (range: 1-12). Eleven of 28 patients had an adverse event related to the antimicrobial treatment, and four had to discontinue linezolid, but all adverse events were reversible within 2 months after discontinuation. Conclusions: Oral linezolid administration combined with adequate surgical treatment may be useful for the treatment of PJIs caused by CoNS.


Assuntos
Antibacterianos/uso terapêutico , Linezolida/uso terapêutico , Infecções Relacionadas à Prótese/tratamento farmacológico , Infecções Estafilocócicas/tratamento farmacológico , Staphylococcus/efeitos dos fármacos , Administração Oral , Idoso , Idoso de 80 Anos ou mais , Coagulase , Feminino , Humanos , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Estudos Retrospectivos , Staphylococcus/enzimologia
16.
Int J Med Microbiol ; 309(6): 151334, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31383542

RESUMO

The bacterial cell wall provides structural integrity to the cell and protects the cell from internal pressure and the external environment. During the course of the twelve-year funding period of the Collaborative Research Center 766, our work has focused on conducting structure-function studies of enzymes that modify (synthesize or cleave) cell wall components of a range of bacteria including Staphylococcus aureus, Staphylococcus epidermidis, and Nostoc punctiforme. Several of our structures represent promising targets for interference. In this review, we highlight a recent structure-function analysis of an enzyme complex that is responsible for the amidation of Lipid II, a peptidoglycan precursor, in S. aureus.


Assuntos
Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Complexos Multienzimáticos/química , Complexos Multienzimáticos/metabolismo , Peptidoglicano/metabolismo , Parede Celular/enzimologia , Parede Celular/metabolismo , Peptidoglicano/química , Domínios Proteicos , Staphylococcus/enzimologia , Staphylococcus/metabolismo , Relação Estrutura-Atividade , Uridina Difosfato Ácido N-Acetilmurâmico/análogos & derivados , Uridina Difosfato Ácido N-Acetilmurâmico/metabolismo
17.
J Dairy Sci ; 102(10): 8734-8744, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31421877

RESUMO

Brining is an important step in cheese making, and using brine baths for this purpose is common practice in German dairies. Time of brining, brine concentration, and composition of the complex and heterogeneous microbiota, including coagulase-negative staphylococci (CNS), contribute to the ripening and taste of cheese. As well as producing staphylococcal enterotoxins, some CNS show antibiotic resistance; therefore, we isolated 52 strains of presumptive CNS from cheese brines from 13 factories in Germany. Species identification by sodA gene sequencing revealed that 50 isolates were CNS: 31 Staphylococcus saprophyticus, 4 Staphylococcus carnosus, 4 Staphylococcus equorum, 3 Staphylococcus sciuri, 2 Staphylococcus hominis, and 2 Staphylococcus warneri. One isolate each was identified as Staphylococcus epidermidis, Staphylococcus pasteurii, Staphylococcus succinus, and Staphylococcus xylosus. Further subtyping of the Staph. saprophyticus isolates to the subspecies level revealed the presence of 6 Staph. saprophyticus ssp. saprophyticus. Using pulsed-field gel electrophoresis with the identified Staph. saprophyticus strains, 12 independent clones were identified, resulting in the exclusion of 18 strains from further testing. In 19 of the remaining 32 CNS isolates, resistance to antibiotics was observed. Resistance was found against oxacillin (17), penicillin (5), and cefoxitin (1). Four isolates expressed resistance to both oxacillin and penicillin. No resistance was found to enrofloxacin, tetracycline, gentamicin, or erythromycin. Then, PCR analysis for antibiotic resistance genes was performed for 22 different genes. Only genes blaZ and blaTEM were found in 7 isolates. These isolates were selected for challenge tests with different concentrations of lactic acid and NaCl to examine whether expression of antibiotic resistance was influenced by these stressors. An increase in the minimal inhibitory concentration from 0 to 2.0 µg/mL was seen for trimethoprim/sulfamethoxazole only in one isolate of Staph. saprophyticus at an increased lactic acid concentration. Finally, all isolates were tested for genetic determinants (entA, entB, entC, entD, and entE) of the most common staphylococcal enterotoxins; none of these genes were detected. We found no indication for unacceptable risks originating from the isolated CNS.


Assuntos
Queijo/microbiologia , Sais , Staphylococcus/isolamento & purificação , Animais , Antibacterianos/farmacologia , Cefoxitina/farmacologia , Coagulase/genética , Farmacorresistência Bacteriana , Eletroforese em Gel de Campo Pulsado , Enterotoxinas/genética , Manipulação de Alimentos , Alemanha , Testes de Sensibilidade Microbiana , Oxacilina/farmacologia , Penicilina G/análise , Staphylococcus/classificação , Staphylococcus/efeitos dos fármacos , Staphylococcus/enzimologia , Staphylococcus epidermidis/genética
18.
Rev Esp Quimioter ; 32 Suppl 3: 24-28, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31364338

RESUMO

Ceftobiprole is a new cephalosporin with an extended spectrum activity against the majority of microorganisms isolated in bacteremia including methicillin-susceptible (MSSA) and -resistant S. aureus (MRSA). This antibiotic has demonstrated a potent activity against MRSA in animal models of endocarditis in monotherapy but particularly in combination with daptomycin, suggesting that this combination could be a future option to improve the outcome of staphylococcal endovascular infections. In addition, the extended-spectrum ceftobiprole activity, including coagulase-negative staphylococci, Enterococcus faecalis, Enterobacteriaceae and Pseudomonas aeruginosa represents an advantage for use as empirical therapy in bacteremia potentially caused by a broad spectrum of microorganisms, such as in catheter-related bacteremia.


Assuntos
Antibacterianos/uso terapêutico , Bacteriemia/tratamento farmacológico , Cefalosporinas/uso terapêutico , Infecções Estafilocócicas/tratamento farmacológico , Bacteriemia/microbiologia , Daptomicina/uso terapêutico , Quimioterapia Combinada/métodos , Humanos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Pseudomonas aeruginosa/efeitos dos fármacos , Infecções Estafilocócicas/microbiologia , Staphylococcus/efeitos dos fármacos , Staphylococcus/enzimologia , Staphylococcus aureus/efeitos dos fármacos
19.
Cir Cir ; 87(4): 428-435, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31264992

RESUMO

Objective: To determine the prevalence and virulence factors of coagulase-negative Staphylococci (CNS) in prosthetic joint infections (PJI). Method: CNS were isolated of 66 hip and knee PJI from Instituto Nacional de Rehabilitación Luis Guillermo Ibarra Ibarra, México City. Antimicrobial susceptibility and biofilm formation in CNS were determined; icaADBC, aap, bap and embp genes were determined by PCR. Results: Staphylococcus and Staphylococcus hominis were the most prevalent with 82 y 80% respectively. Staphylococcus lugdunensis, Staphylococcus haemolyticus, Staphylococcus capitis, Staphylococcus caprae, Staphylococcus sciuri and Staphylococcus lentus were less frequent. The majority of isolates were resistant to ß-lactam antibiotics, fluoroquinolone, and erythromycin. 41% of CNS were biofilm former and 59% were non-biofilm former (p = 0.0551). Biofilm former Staphylococcus epidermidis showed a high presence of icaADBC, aap and embp operons compared to the non-biofilm former isolates (p < 0.05). In contrast, non-S. epidermidis CNS had only the aap gen. Conclusion: S. haemolyticus, S. sciuri and S. lentus are new isolates of PJI not previously reported with virulence factors similar to CNS isolates.


Assuntos
Biofilmes/crescimento & desenvolvimento , Prótese do Joelho/microbiologia , Infecções Relacionadas à Prótese/microbiologia , Staphylococcus/isolamento & purificação , Fatores de Virulência/isolamento & purificação , Adulto , Idoso , Idoso de 80 Anos ou mais , Proteínas de Bactérias/genética , Coagulase , Farmacorresistência Bacteriana Múltipla/genética , Feminino , Genes Bacterianos , Prótese de Quadril/microbiologia , Prótese de Quadril/estatística & dados numéricos , Hospitais Especializados , Humanos , Masculino , México , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Ortopedia , Estudos Retrospectivos , Staphylococcus/classificação , Staphylococcus/enzimologia , Staphylococcus/fisiologia , Adulto Jovem
20.
Microb Pathog ; 135: 103616, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31283961

RESUMO

The antibiotic resistance among coagulase - negative Staphylococcus (CoNS) species towards methicillin is rarely reported in veterinary medicine. Under the aspect/concept of One Health, those strains pose a risk to human health due to the presence in canine pets where the transfer of resistant genetic markers might occur to other staphylococci species. The aim of this study was to investigate the antimicrobial resistance pattern among Coagulase Negative Staphylococci (CoNS) isolated from asymptomatic dogs and those affected by topic infections. Swabs from 254 dogs were first seeded in Mannitol Salt Agar. Species identification was conducted by Matrix Assisted Laser Desorption ionization - time of flight (MALDI-TOF ms) as previously described. The susceptibility test was performed by disk diffusion according to CLSI standards. Detection of mecA gene was performed. CoNS could be recovered from both groups of dogs and an alarming presence of methicillin-resistant coagulase negative staphylococci (MRCoNS) was confirmed, in 10.2% (17/166) of the samples. Eight of those methicillin resistant strains were isolated from asymptomatic dogs whereas nine were present in dogs affected by pyoderma and otitis externa.


Assuntos
Coagulase/deficiência , Reservatórios de Doenças/microbiologia , Doenças do Cão/microbiologia , Resistência a Meticilina , Infecções Estafilocócicas/veterinária , Staphylococcus/isolamento & purificação , Animais , Antibacterianos/farmacologia , Doenças do Cão/transmissão , Cães , Farmacorresistência Bacteriana , Genes Bacterianos , Humanos , Resistência a Meticilina/genética , Testes de Sensibilidade Microbiana , Proteínas de Ligação às Penicilinas , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Infecções Estafilocócicas/microbiologia , Infecções Estafilocócicas/transmissão , Staphylococcus/classificação , Staphylococcus/enzimologia , Staphylococcus/genética
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