Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 8.607
Filtrar
1.
Zhonghua Liu Xing Bing Xue Za Zhi ; 40(8): 904-910, 2019 Aug 10.
Artigo em Chinês | MEDLINE | ID: mdl-31484252

RESUMO

Objective: To analyze the etiologic and epidemiological characteristics of adult acute respiratory infections in Shanghai during 2015-2017. Methods: Data was collected from outpatients with acute respiratory infections who visited the Fever Clinics in three hospitals of different levels in three administrative regions of Shanghai, from 2015 to 2017. Basic information and nasopharyngeal swabs were collected from cases in line with the inclusion criteria. Multiplex RT-PCR and bacterial cultures were performed to detect the respiratory pathogens. Results: A total of 806 individuals were enrolled from 2015 to 2017. Respiratory pathogens were identified in 73.45% (592/806) of the cases, with the virus detection rate as 66.75% (538/806). It was found that the major respiratory pathogens for virus detection were influenza A in 326 (40.45%), influenza B in 116 (14.39%), rhinovirus/enterovirus in 39 (4.84%) of the cases. The overall detection rate of bacteria was 16.13% (130/806), including Klebsiella pneumoniae in 90 (11.17%) cases, Staphylococcus Aureus in 46 (5.71%) cases. Other kind of bacteria were not detected in our study. The detection rates on Mycoplasma pneumoniae was 5.33% (43/806) and on Chlamydia pneumonia was 0.37% (3/806). Co-infection with multiple pathogens was detected in 18.61% (150/806) of the cases, including 135 with double infection (accounting for 90.00%), 14 with triple infection and 1 with quadruple infection (accounted for 9.33% and 0.67%, respectively). Among the 150 cases with co-infections, the main identified pathogens were influenza A, Klebsiella pneumoniae, Staphylococcus aureus, and Mycoplasma pneumoniae. Pathogens of acute respiratory infections that identified among the outpatients from the Fever Clinics at different time, region or population, the characteristics were different (P<0.001). Conclusions: In 2015-2017, outpatients with acute respiratory infections in Shanghai were mainly caused by influenza virus or other viruses, however dynamically with its composition, time, region and characteristics of the population. It is necessary to strengthen and combine related medical and preventive services and to develop the appropriate strategies regarding clinical diagnosis and treatment.


Assuntos
Bactérias/isolamento & purificação , Infecções Bacterianas/diagnóstico , Influenza Humana/diagnóstico , Reação em Cadeia da Polimerase Multiplex/métodos , Nasofaringe , Infecções Respiratórias/epidemiologia , Infecções Respiratórias/etiologia , Viroses/diagnóstico , Vírus/isolamento & purificação , Doença Aguda , Adulto , Bactérias/genética , Infecções Bacterianas/epidemiologia , Infecções Bacterianas/microbiologia , China/epidemiologia , Coinfecção/diagnóstico , Enterovirus/genética , Enterovirus/isolamento & purificação , Monitoramento Epidemiológico , Humanos , Incidência , Vírus da Influenza A/genética , Vírus da Influenza A/isolamento & purificação , Vírus da Influenza B/genética , Vírus da Influenza B/isolamento & purificação , Influenza Humana/epidemiologia , Influenza Humana/virologia , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/isolamento & purificação , Mycoplasma pneumoniae , Nasofaringe/microbiologia , Nasofaringe/virologia , Vigilância da População , Infecções Respiratórias/diagnóstico , Rhinovirus/genética , Rhinovirus/isolamento & purificação , Staphylococcus aureus/genética , Staphylococcus aureus/isolamento & purificação , Viroses/epidemiologia , Viroses/virologia , Vírus/genética
2.
APMIS ; 127(11): 717-726, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31407405

RESUMO

This study aims to determine the prevalence of Staphylococcus aureus colonizing patients and ICU environment of a teaching hospital, the virulence and antimicrobial susceptibility profile of the isolates, and to evaluate the genetic relationship among them. A total of 536 swabs (134 of patients and 402 of ICU environment) were collected and analyzed to detect S. aureus. The antimicrobial susceptibility of the isolates was determined by disk diffusion test, and the detection of the mecA and virulence factors genes was performed by PCR, in addition to SCCmec typing. The genetic similarity of the isolates was determined by PFGE. Staphylococcus aureus was isolated in 12.7% of the swabs. The prevalence of colonization was 13.4% in patients and 12.4% in the environmental samples. The multidrug resistance was determined in 82.4% of the isolates. The prevalence of methicillin-resistant S. aureus was 20.6%, with 50.0% classified as SCCmec IV. The intermediate resistance to vancomycin was detected in 5.9% and 4.4% of the isolates obtained from patients and environment, respectively. Identical isolates obtained from different patients and sources were grouped into several clusters. The results showed dissemination of multidrug-resistant strains between patients and fomites and the persistence of MRSA and VISA isolates in the ICU environment.


Assuntos
Antibacterianos/farmacologia , Resistência a Meticilina , Staphylococcus aureus Resistente à Meticilina/genética , Staphylococcus aureus Resistente à Meticilina/patogenicidade , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/genética , Staphylococcus aureus/patogenicidade , Proteínas de Bactérias/genética , Farmacorresistência Bacteriana , Feminino , Variação Genética , Humanos , Unidades de Terapia Intensiva/estatística & dados numéricos , Masculino , Meticilina/farmacologia , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/crescimento & desenvolvimento , Testes de Sensibilidade Microbiana , Filogenia , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento , Vancomicina/farmacologia , Virulência , Fatores de Virulência/genética
3.
Nat Commun ; 10(1): 3067, 2019 07 11.
Artigo em Inglês | MEDLINE | ID: mdl-31296851

RESUMO

WalKR (YycFG) is the only essential two-component regulator in the human pathogen Staphylococcus aureus. WalKR regulates peptidoglycan synthesis, but this function alone does not explain its essentiality. Here, to further understand WalKR function, we investigate a suppressor mutant that arose when WalKR activity was impaired; a histidine to tyrosine substitution (H271Y) in the cytoplasmic Per-Arnt-Sim (PASCYT) domain of the histidine kinase WalK. Introducing the WalKH271Y mutation into wild-type S. aureus activates the WalKR regulon. Structural analyses of the WalK PASCYT domain reveal a metal-binding site, in which a zinc ion (Zn2+) is tetrahedrally-coordinated by four amino acids including H271. The WalKH271Y mutation abrogates metal binding, increasing WalK kinase activity and WalR phosphorylation. Thus, Zn2+-binding negatively regulates WalKR. Promoter-reporter experiments using S. aureus confirm Zn2+ sensing by this system. Identification of a metal ligand recognized by the WalKR system broadens our understanding of this critical S. aureus regulon.


Assuntos
Proteínas de Bactérias/metabolismo , Histidina Quinase/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Staphylococcus aureus/metabolismo , Zinco/metabolismo , Substituição de Aminoácidos , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Cátions Bivalentes/metabolismo , Histidina/genética , Histidina Quinase/química , Histidina Quinase/genética , Simulação de Dinâmica Molecular , Mutação , Proteínas Serina-Treonina Quinases/química , Proteínas Serina-Treonina Quinases/genética , Regulon/genética , Staphylococcus aureus/genética , Tirosina/genética
4.
BMC Infect Dis ; 19(1): 584, 2019 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-31349818

RESUMO

BACKGROUND: Community-acquired sepsis is a life-threatening systemic reaction, which starts within ≤72 h of hospital admittance in an infected patient without recent exposure to healthcare risks. Our aim was to evaluate the characteristics and the outcomes concerning community-acquired sepsis among patients admitted to a Hungarian high-influx national medical center. METHODS: A retrospective, observational cohort study of consecutive adult patients hospitalized with community-acquired sepsis during a 1-year period was executed. Clinical and microbiological data were collected, patients with pre-defined healthcare associations were excluded. Sepsis definitions and severity were given according to ACCP/SCCM criteria. The primary outcome was in-hospital all-cause mortality. Secondary outcomes were intensive care unit (ICU) admittance, length-of-stay (LOS), source control and bacteraemia rates. Statistical differences were explored with classical comparison tests, predictors of in-hospital all-cause mortality were modelled by multivariate logistic regression. RESULTS: 214 patients (median age 60.0 ± 33.1 years, 57% female, median Charlson score 4.0 ± 5.0) were included, 32.7% of them (70/214) had severe sepsis, and 28.5% (61/214) had septic shock. Prevalent sources of infections were genitourinary (53/214, 24.8%) and abdominal (52/214, 24.3%). The causative organisms were dominantly E. coli (60/214, 28.0%), S. pneumoniae (18/214, 8.4%) and S. aureus (14/214, 6.5%), and bacteraemia was documented in 50.9% of the cases (109/214). In-hospital mortality was high (30/214, 14.0%), and independently associated with shock, absence of fever, male gender and the need for ICU admittance, but source control and de-escalation of empirical antimicrobial therapy were protective. ICU admittance was 27.1% (58/214), source control was achieved in 18.2% (39/214). Median LOS was 10.0 ± 8.0, ICU LOS was 8.0 ± 10.8 days. CONCLUSIONS: Community-acquired sepsis poses a significant burden of disease with characteristic causative agents and sources. Patients at a higher risk for poor outcomes might be identified earlier by the contributing factors shown above.


Assuntos
Sepse/tratamento farmacológico , Choque Séptico/tratamento farmacológico , Adulto , Idoso , Idoso de 80 Anos ou mais , Antibacterianos/uso terapêutico , Estudos de Coortes , Infecções Comunitárias Adquiridas , Escherichia coli/genética , Escherichia coli/isolamento & purificação , Feminino , Mortalidade Hospitalar , Hospitalização , Humanos , Hungria , Unidades de Terapia Intensiva/estatística & dados numéricos , Tempo de Internação , Masculino , Pessoa de Meia-Idade , Prevalência , Estudos Retrospectivos , Sepse/microbiologia , Sepse/mortalidade , Choque Séptico/microbiologia , Choque Séptico/mortalidade , Staphylococcus aureus/genética , Staphylococcus aureus/isolamento & purificação , Adulto Jovem
5.
Vet Microbiol ; 235: 93-100, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31282384

RESUMO

Staphylococcus aureus biofilm-related infections are of clinical concern due to the capability of bacterial colonies to adapt to a hostile environment. The present study investigated the capability of the acute phase protein alpha 1-acid glycoprotein (AGP) to a) disrupt already established S. aureus biofilm and b) interfere with the biofilm de novo production by using Microtiter Plate assay (MtP) on field strains isolated from infected quarters by assessing. The present study also investigated whether AGP could interfere with the expression of bacterial genes related to biofilm formation (icaA, icaD, icaB, and icaC) and adhesive virulence determinants (fnbA, fnbB, clfA, clfB, fib, ebps, eno) by quantitative real-time PCR (qPCR). The results provided the evidence that AGP could disrupt the biofilm structure only when it was already developed, but could not prevent the de novo biofilm formation. Moreover, AGP could interfere with the expression levels of genes involved in biofilm formation in a dose- and strain-dependent way, by upregulating, or downregulating, icaABC genes and fnbB, respectively. The results presented in this study provide new insights about the direct antibacterial activity of AGP in bovine milk. It remains to be demonstrated the molecular bases of AGP mechanism of action, in particular for what concerns the scarce capability to interact with the de novo formation of biofilm.


Assuntos
Biofilmes , Orosomucoide/metabolismo , Infecções Estafilocócicas/veterinária , Staphylococcus aureus/patogenicidade , Animais , Bovinos , Feminino , Genes Bacterianos , Genótipo , Leite/química , Staphylococcus aureus/genética , Fatores de Virulência/genética
6.
Rev Soc Bras Med Trop ; 52: e20190095, 2019 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-31340369

RESUMO

INTRODUCTION: Staphylococcus aureus is a major nosocomial pathogen that is associated with high virulence and the rapid development of drug resistance. METHODS: We analyzed and compared the antimicrobial resistance, virulence profiles, and molecular epidemiology of 67 S. aureus strains, including 36 methicillin-sensitive (MSSA) and 31 methicillin-resistant (MRSA) strains recovered from a public hospital located in south-eastern Brazil. RESULTS: The clones circulating in this hospital presented a great diversity, and the majority of the strains were related to clones responsible for causing worldwide epidemics: these included USA100 (New York/Japan clone), USA300, and USA600. The 31 MRSA (22 SCCmecII and 9 SCCmecIV) and 36 MSSA strains exhibited low resistance against gentamicin and trimethoprim/sulfamethoxazole. No MRSA strain showed resistance to tetracycline. Virulence gene carriage was more diverse and abundant in MSSA than in MRSA. Of the evaluated adhesion-related genes, ebpS was the most prevalent in both MSSA and MRSA strains. The genes bbp and cna showed a strong association with MSSA strains. CONCLUSIONS: Our findings reinforce the idea that MSSA and MRSA strains should be carefully monitored, owing to their high pathogenic potential.


Assuntos
Antibacterianos/farmacologia , Resistência a Meticilina , Staphylococcus aureus Resistente à Meticilina/genética , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/genética , Fatores de Virulência/genética , Brasil/epidemiologia , Hospitais Públicos , Humanos , Testes de Sensibilidade Microbiana , Epidemiologia Molecular , Infecções Estafilocócicas/epidemiologia , Staphylococcus aureus/classificação , Staphylococcus aureus/isolamento & purificação , Centros de Atenção Terciária , Virulência/genética
7.
J Agric Food Chem ; 67(30): 8382-8392, 2019 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-31271032

RESUMO

Staphylococcus aureus is a common pathogen that can cause life-threatening infections. Treatment of antibiotic-resistant S. aureus infection needs effective antibacterial agents. Thymol, a generally recognized safe natural compound, has potential as an alternative to treat S. aureus infections. However, the targets and mechanisms of action of thymol were not fully understood. Bioinformatics analysis showed that IolS, a predicted aldo-keto reductase (AKR) in S. aureus, could be a potential target of thymol. Isothermal titration calorimetry (ITC) analysis demonstrated that thymol directly binds IolS and amino acid residues (Y30 and L33) are essential for such binding. Deletion of IolS or mutation of Y30A and L33A reduced the bactericidal activity of thymol at the concentration of 200 µg/mL, suggesting that thymol mediates bactericidal activity via binding with IolS. Biochemical analysis showed that addition of thymol significantly increased AKR activity of IolS from 1.6 ± 0.1 to 2.4 ± 0.2 U (p < 0.05). The content of NADPH within S. aureus cells decreased significantly from 105 ± 5 to 72 ± 3 pmol/108 cells (p < 0.05) following thymol treatment at the concentration of 200 µg/mL. Importantly, addition of NADPH could alleviate the bactericidal effect of thymol on S. aureus, indicating that the depletion of NADPH is responsible for thymol-mediated bactericidal activity. Overall, these results demonstrated that thymol could directly bind IolS and increase its AKR activity, leading to the depletion of NADPH and bactericidal effect. AKR activity of IolS could be a promising target for the development of new antimicrobials.


Assuntos
Aldo-Ceto Redutases/antagonistas & inibidores , Antibacterianos/farmacologia , Proteínas de Bactérias/antagonistas & inibidores , NADP/metabolismo , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/enzimologia , Timol/farmacologia , Aldo-Ceto Redutases/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Humanos , Testes de Sensibilidade Microbiana , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/genética
8.
J Dairy Sci ; 102(8): 6923-6927, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31178176

RESUMO

Reports of ß-lactam-resistant Staphylococcus aureus in artisanal goat cheese are increasing, and this phenomenon is relevant to public health. The objective of the present study was to determine the prevalence of S. aureus strains carrying the blaZ and mecA resistance genes, as well as the genes encoding the staphylococcal enterotoxins SEA, SEB, SEC, SED, SEE, and TSST-1 in artisanal coalho cheese made from goat milk produced in northeastern Brazil. We used biochemical and molecular tests to characterize 54 S. aureus isolates found in artisanal coalho cheese collected from commercial establishments producing animal products in 11 municipalities of Pernambuco State, Brazil. A PCR analysis revealed that 42.6% (23/54) of the isolates were positive for the blaZ gene, and 7.4% (4/54) were resistant to methicillin by phenotypic testing. We did not detect mecA or any genes encoding enterotoxins. The presence of S. aureus carriers of the blaZ gene and the identification of methicillin-resistant S. aureus strains are of concern for the health of consumers of this type of cheese.


Assuntos
Queijo/microbiologia , Resistência a Meticilina/genética , Leite/microbiologia , Staphylococcus aureus/fisiologia , Resistência beta-Lactâmica/genética , beta-Lactamases/genética , Animais , Antibacterianos/farmacologia , Brasil , Feminino , Cabras , Staphylococcus aureus Resistente à Meticilina/enzimologia , Staphylococcus aureus Resistente à Meticilina/genética , Staphylococcus aureus Resistente à Meticilina/fisiologia , Staphylococcus aureus/enzimologia , Staphylococcus aureus/genética
9.
Int J Food Microbiol ; 305: 108244, 2019 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-31202150

RESUMO

This study examined the prevalence and phenotypic and genotypic antibiotic resistance patterns of Staphylococcus aureus in sushi from 20 Danish outlets. Microbial quality of sushi products and food inspector ranking of outlets were assessed and results for thirteen of the outlets were compared with findings from a previous study in 2012. Inspector rankings were similar in the two studies. The mesophilic aerobic counts were slightly lower (p = 0.0296) in 2017 than in 2012 with average values of the 13 shops of 5.2 log CFU/g and 5.7 log CFU/g, respectively. In both studies E. coli was only found in the products from outlets that did not have consistently superior rankings. On the other hand prevalence and average counts of Staphylococcus spp. were slightly higher in 2017 (p = 0.0286) but no methicillin-resistant S. aureus (MRSA) were observed in the present study. Methicillin-sensitive S. aureus (MSSA) were, however, isolated from 18.7% of sushi products with an average count below 2 log CFU/g. Based on spa and multilocus sequence typing (MLST), isolates belonged to clonal complex CC7 (t2016), CC20 (t7836), CC45 (t065, t127, t362), CC88 (t1998) and CC398 (t164, t331, t1451). The Panton-Valentine leukocidin (PVL)-encoding gene lukF was detected only in isolates of the t065 spa-type whereas the scn gene from the ΦSa3 prophage was detected in 76.5% of the isolates, supporting that the majority of isolates were of likely human origin. Thirty-six isolates (70.6%) were resistant to at least one of the antibiotic compounds tested. Antibiotic resistance genes that confer resistance to ß-lactams (blaZ) and macrolides (ermC) were detected in 33.3% and 9.8% of isolates, respectively. The tet(K) gene that encode tetracycline resistance was only found in a t7836 strain. Overall, this study indicates that S. aureus in sushi products in Denmark do not represent a major food safety hazard due to, firstly, the low temperature and limited time of storage of product may prevent significant growth and production of toxic levels of enterotoxin of this species. Secondly, the S. aureus isolates obtained did not include MRSA variants and none of them encoded PVL that constitute one of the virulence factors in pathogenesis. Several MSSA isolates contained however genes encoding antibiotic resistance, which emphasize the potential role of foods as vehicles for transmission of such variants.


Assuntos
Farmacorresistência Bacteriana , Produtos Pesqueiros/microbiologia , Inspeção de Alimentos/normas , Animais , Antibacterianos/farmacologia , Dinamarca , Escherichia coli/classificação , Escherichia coli/genética , Escherichia coli/isolamento & purificação , Peixes , Humanos , Meticilina/farmacologia , Staphylococcus aureus Resistente à Meticilina/classificação , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/genética , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Testes de Sensibilidade Microbiana , Tipagem de Sequências Multilocus , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/classificação , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/genética , Staphylococcus aureus/isolamento & purificação , Fatores de Virulência/genética , beta-Lactamas/farmacologia
10.
Anal Chim Acta ; 1075: 128-136, 2019 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-31196418

RESUMO

A fluorescent detection of Staphylococcus aureus (S. aureus) is established based on a finely designed functional chimera sequence, a molecular beacon (MB), and strand displacement target recycling. The chimera sequence, which consists of the aptamer sequence of S. aureus and the complementary sequence of MB, can form a hairpin structure due to the existence of intramolecular complementary regions. When S. aureus is present, it binds to the aptamer region of the chimera, opens the hairpin and unlocks the complementary sequence of MB. Subsequently, the MB is opened and intensive fluorescence signal is restored. To increase the sensitivity of the detection, signal amplification is achieved through strand displacement-based target recycling. With the catalysis of Nb. Bpu10I nicking endonuclease and Bsm DNA polymerase, the MB sequence can be cleaved and then elongated to form a complete duplex with the chimera, during which S. aureus is displaced from the chimera and proceeded to the next round of the reaction. This assay displays a linear correlation between the fluorescence intensity and the logarithm of the concentration of S. aureus within a broad concentration range from 80 CFU/mL to 8 × 106 CFU/mL. The detection limit of 39 CFU/mL can be derived. The assay was applied to detect S. aureus in different water samples, and satisfactory recovery and repeatability were achieved. Hence the designed chimera sequence and established assay have potential application in environmental pollution monitoring.


Assuntos
Aptâmeros de Nucleotídeos/química , DNA Bacteriano/análise , Staphylococcus aureus/isolamento & purificação , Aptâmeros de Nucleotídeos/genética , Técnicas de Tipagem Bacteriana/métodos , Sequência de Bases , Técnicas Biossensoriais/métodos , DNA Bacteriano/química , DNA Bacteriano/genética , Desoxirribonuclease I/química , Água Potável/microbiologia , Monitoramento Ambiental/métodos , Fluoresceínas/química , Fluorescência , Corantes Fluorescentes/química , Sequências Repetidas Invertidas , Lagos/microbiologia , Limite de Detecção , Técnicas de Amplificação de Ácido Nucleico/métodos , Hibridização de Ácido Nucleico , Tanques/microbiologia , Espectrometria de Fluorescência , Staphylococcus aureus/genética
11.
Klin Lab Diagn ; 64(5): 294-298, 2019.
Artigo em Russo | MEDLINE | ID: mdl-31185153

RESUMO

Clinical strains of Staphylococcus aureus were tested for hemolytic activity on blood agar, in the PCR test and by analyzing the gene alleles of hemolytic toxins. The study analyzed the information content of the phenotypic determination of hemolytic activity to assess the pathogenic properties of S. aureus isolates.


Assuntos
Toxinas Bacterianas/genética , Hemólise , Staphylococcus aureus/patogenicidade , Humanos , Federação Russa , Infecções Estafilocócicas , Staphylococcus aureus/genética
12.
Mol Immunol ; 112: 59-71, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31078117

RESUMO

B-cell survival depends on signals induced by binding of B-cell activating factor (BAFF) to its receptor (BAFF-R). In this study, the full-length cDNAs of cat BAFF (cBAFF) and BAFF-R (cBAFF-R) were amplified from the spleen by reverse transcription PCR. The open reading frame of cBAFF cDNA encodes a protein of 285 amino acids containing a predicted transmembrane domain and a furin protease cleavage site, similar to mammalian, avian, and reptile BAFFs. The cBAFF-R gene encodes a 189 amino acid protein. Real-time quantitative PCR analyses revealed that the two genes are predominantly expressed in the spleen. csBAFF, EGFP/csBAFF, and cBAFF-R were efficiently expressed in Escherichia coli BL21 (DE3), as confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blotting analyses. After purification, the EGFP/csBAFF fusion protein showed a fluorescence spectrum similar to that of EGFP. Confocal laser scanning microscopy showed that EGFP/csBAFF bound to its receptor. In vitro, csBAFF promoted the survival of cat and mouse splenic B cells with/without a priming agent (Staphylococcus aureus Cowan 1, SAC) or anti-mouse IgM. Furthermore, it stimulated the survival of mouse B cells, similar to msBAFF. Recombinant cBAFF-R blocked the function of sBAFF in vitro. These findings indicate that csBAFF plays an important role in the survival of cat B cells and has functional cross reactivity between cats and other mammals, and suggest a role for the BAFF-BAFF-R system in regulating B-cell survival. Therefore, BAFF and BAFF-R show promise for enhancing the immune systems of animals.


Assuntos
Fator Ativador de Células B/genética , Receptor do Fator Ativador de Células B/genética , Linfócitos B/metabolismo , Sequência de Aminoácidos , Animais , Sequência de Bases , Gatos , Sobrevivência Celular/genética , Clonagem Molecular , Reações Cruzadas/genética , DNA Complementar/genética , Escherichia coli/genética , Imunoglobulina M/genética , Mamíferos/genética , Camundongos , Estrutura Molecular , Fases de Leitura Aberta/genética , Proteínas Recombinantes/genética , Baço/metabolismo , Staphylococcus aureus/genética
13.
Int J Infect Dis ; 85: 7-9, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31096050

RESUMO

Staphylococcal scarlet fever (SSF) is characterized by an exanthem without enanthem, bullae, or exfoliation, and is known to be related to Staphylococcus aureus toxins, especially superantigens. It has been reported in children and young adults. Herein, we report the first case of an elderly patient with SSF caused by staphylococcal enterotoxin M (SEM), associated with otitis externa. The patient presented with maculopapular rashes on both arms, thighs, and abdomen and with erythroderma on the face, ears, neck, chest, and back, all of which was followed by desquamation on the face, ears, and trunk. A culture of ear discharge grew methicillin susceptible S. aureus that was only positive for SEM among the superantigens tested.


Assuntos
Enterotoxinas/toxicidade , Escarlatina/microbiologia , Staphylococcus aureus/isolamento & purificação , Idoso , Enterotoxinas/metabolismo , Humanos , Masculino , Escarlatina/diagnóstico , Staphylococcus aureus/genética , Staphylococcus aureus/metabolismo , Superantígenos/genética , Superantígenos/metabolismo
14.
Can J Microbiol ; 65(8): 623-628, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31063703

RESUMO

In this study, vancomycin-intermediate Staphylococcus aureus (VISA) cells carrying vraS and (or) graR mutations were shown to be more resistant to oxidative stress. Caenorhabditis elegans infected with these strains in turn demonstrated lower survival. Altered regulation in oxidative stress response and virulence appear to be physiological adaptations associated with the VISA phenotype in the Mu50 lineage.


Assuntos
Antibacterianos/farmacologia , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/metabolismo , Vancomicina/farmacologia , Animais , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Caenorhabditis elegans , Humanos , Testes de Sensibilidade Microbiana , Mutação , Estresse Oxidativo/efeitos dos fármacos , Fenótipo , Staphylococcus aureus/genética , Resistência a Vancomicina , Virulência/efeitos dos fármacos
15.
PLoS Negl Trop Dis ; 13(5): e0007247, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-31107882

RESUMO

Cutaneous leishmaniasis (CL) is a parasitic disease causing chronic, ulcerating skin lesions. Most humans infected with the causative Leishmania protozoa are asymptomatic. Leishmania spp. are usually introduced by sand flies into the dermis of mammalian hosts in the presence of bacteria from either the host skin, sand fly gut or both. We hypothesized that bacteria at the dermal inoculation site of Leishmania major will influence the severity of infection that ensues. A C57BL/6 mouse ear model of single or coinfection with Leishmania major, Staphylococcus aureus, or both showed that single pathogen infections caused localized lesions that peaked after 2-3 days for S. aureus and 3 weeks for L. major infection, but that coinfection produced lesions that were two-fold larger than single infection throughout 4 weeks after coinfection. Coinfection increased S. aureus burdens over 7 days, whereas L. major burdens (3, 7, 28 days) were the same in singly and coinfected ears. Inflammatory lesions throughout the first 4 weeks of coinfection had more neutrophils than did singly infected lesions, and the recruited neutrophils from early (day 1) lesions had similar phagocytic and NADPH oxidase capacities. However, most neutrophils were apoptotic, and transcription of immunomodulatory genes that promote efferocytosis was not upregulated, suggesting that the increased numbers of neutrophils may, in part, reflect defective clearance and resolution of the inflammatory response. In addition, the presence of more IL-17A-producing γδ and non-γδ T cells in early lesions (1-7 days), and L. major antigen-responsive Th17 cells after 28 days of coinfection, with a corresponding increase in IL-1ß, may recruit more naïve neutrophils into the inflammatory site. Neutralization studies suggest that IL-17A contributed to an enhanced inflammatory response, whereas IL-1ß has an important role in controlling bacterial replication. Taken together, these data suggest that coinfection of L. major infection with S. aureus exacerbates disease, both by promoting more inflammation and neutrophil recruitment and by increasing neutrophil apoptosis and delaying resolution of the inflammatory response. These data illustrate the profound impact that coinfecting microorganisms can exert on inflammatory lesion pathology and host adaptive immune responses.


Assuntos
Coinfecção/imunologia , Interleucina-17/imunologia , Leishmania major/fisiologia , Leishmaniose Cutânea/imunologia , Infecções Estafilocócicas/imunologia , Staphylococcus aureus/fisiologia , Animais , Coinfecção/microbiologia , Coinfecção/parasitologia , Coinfecção/patologia , Feminino , Humanos , Interleucina-17/genética , Interleucina-1beta/genética , Interleucina-1beta/imunologia , Leishmania major/genética , Leishmania major/isolamento & purificação , Leishmaniose Cutânea/genética , Leishmaniose Cutânea/parasitologia , Leishmaniose Cutânea/patologia , Camundongos , Camundongos Endogâmicos C57BL , Neutrófilos/imunologia , Infecções Estafilocócicas/genética , Infecções Estafilocócicas/microbiologia , Infecções Estafilocócicas/patologia , Staphylococcus aureus/genética , Staphylococcus aureus/isolamento & purificação , Células Th17/imunologia
16.
Microb Pathog ; 133: 103543, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31102653

RESUMO

PURPOSE: Whole genome sequencing (WGS) analysis of Staphylococcus aureus is increasingly used in clinical practice. Although bioinformatics tools used in WGS analysis readily define the S. aureus virulome, the clinical value of this type of analysis is unclear. Here, virulence genes in S. aureus bacteremia (SAB) isolates were evaluated by WGS, with superantigens (SAgs) further evaluated by conventional PCR and functional assays, and results correlated with mortality. METHODS: 152 SAB isolates collected throughout 2015 at a large Minnesota medical center were studied and associated clinical data analyzed. Virulence genes were identified from previously-reported WGS data (https://doi.org/10.1371/journal.pone.0179003). SAg genes sea, seb, sec, sed, see, seg, seh, sei, sej, and tst were also assessed by individual PCR assays. Mitogenicity of SAgs was assessed using an in vitro proliferation assay with splenocytes from HLA-DR3 transgenic mice. RESULTS: Of the 152 SAB isolates studied, 106 (69%) were methicillin-susceptible S. aureus (MSSA). The number of deaths attributed and not attributed to SAB, and 30-day survivors were 24 (16%), 2 (1%), and 128 (83%), respectively. From WGS data, both MSSA and MRSA had high proportions of adhesion (>80%) and immune-evasion (>70%) genes. There was no difference in virulomes between survivor- and non-survivor-associated isolates. Although over 60% of SAB isolates produced functional SAgs, there were no differences in the distribution or prevalence of SAg genes between survivor- and non-survivor-associated isolates. CONCLUSION: In this study of one year of SAB isolates from a large medical center, the S. aureus virulome, as assessed by WGS, and also for SAgs using individual PCRs and phenotypic characterization, did not impact mortality.


Assuntos
Bacteriemia/microbiologia , Bacteriemia/mortalidade , Farmacorresistência Bacteriana/genética , Infecções Estafilocócicas/microbiologia , Infecções Estafilocócicas/mortalidade , Staphylococcus aureus/genética , Staphylococcus aureus/patogenicidade , Idoso , Idoso de 80 Anos ou mais , Animais , Bacteriemia/imunologia , Aderência Bacteriana/genética , Sequência de Bases , Proliferação de Células , Feminino , Antígeno HLA-DR3 , Humanos , Evasão da Resposta Imune/genética , Masculino , Staphylococcus aureus Resistente à Meticilina/genética , Camundongos , Camundongos Transgênicos , Pessoa de Meia-Idade , Minnesota , Reação em Cadeia da Polimerase , Infecções Estafilocócicas/imunologia , Superantígenos/genética , Superantígenos/imunologia , Virulência/genética , Fatores de Virulência/genética
17.
Molecules ; 24(9)2019 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-31067626

RESUMO

The occurrence of damage on bacterial DNA (mediated by antibiotics, for example) is intimately associated with the activation of the SOS system. This pathway is related to the development of mutations that might result in the acquisition and spread of resistance and virulence factors. The inhibition of the SOS response has been highlighted as an emerging resource, in order to reduce the emergence of drug resistance and tolerance. Herein, we evaluated the ability of betulinic acid (BA), a plant-derived triterpenoid, to reduce the activation of the SOS response and its associated phenotypic alterations, induced by ciprofloxacin in Staphylococcus aureus. BA did not show antimicrobial activity against S. aureus (MIC > 5000 µg/mL), however, it (at 100 and 200 µg/mL) was able to reduce the expression of recA induced by ciprofloxacin. This effect was accompanied by an enhancement of the ciprofloxacin antimicrobial action and reduction of S. aureus cell volume (as seen by flow cytometry and fluorescence microscopy). BA could also increase the hyperpolarization of the S. aureus membrane, related to the ciprofloxacin action. Furthermore, BA inhibited the progress of tolerance and the mutagenesis induced by this drug. Taken together, these findings indicate that the betulinic acid is a promising lead molecule in the development helper drugs. These compounds may be able to reduce the S. aureus mutagenicity associated with antibiotic therapies.


Assuntos
Farmacorresistência Bacteriana/efeitos dos fármacos , Recombinases Rec A/genética , Staphylococcus aureus/genética , Triterpenos/farmacologia , Ciprofloxacino/efeitos adversos , Ciprofloxacino/farmacologia , DNA Bacteriano/efeitos dos fármacos , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Humanos , Mutagênese/efeitos dos fármacos , Mutagênese/genética , Resposta SOS (Genética)/efeitos dos fármacos , Resposta SOS (Genética)/genética , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/patogenicidade , Fatores de Virulência/genética
18.
Food Chem ; 294: 468-476, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31126489

RESUMO

Detection of pathogenic bacteria by polymerase chain reaction (PCR) is progressively emerging, although it is still hindered by a complex matrix, long-term bacterial enrichment and low bacterial abundance. Here, we report a novel material based on boronate affinity for recognition and enrichment of bacteria using a pre-PCR method. After optimization, the material exhibited high boronate affinity toward bacteria, with adsorption capacities of S. aureus and Salmonella spp. incubated in 0.01 M PBS (pH 7.4) at 37 °C for 15 min calculated as (906.60 ±â€¯15.73) × 107 cfu/g and (582.59 ±â€¯13.19) × 107 cfu/g, respectively, without any bacterial death during the binding process. The material was then applied to enrich S. aureus and Salmonella spp. from the spiked water and 25% cow milk samples followed by mPCR, which resulted in high bacterial enrichment and demonstrated great potential for selective enrichment of bacteria in food samples.


Assuntos
Compostos de Boro/química , Microbiologia de Alimentos/métodos , Salmonella/isolamento & purificação , Staphylococcus aureus/isolamento & purificação , Adsorção , Animais , Compostos de Boro/síntese química , Bovinos , Água Potável/microbiologia , Doenças Transmitidas por Alimentos/microbiologia , Concentração de Íons de Hidrogênio , Leite/microbiologia , Polietilenoimina/química , Reação em Cadeia da Polimerase , Salmonella/genética , Sensibilidade e Especificidade , Sefarose/química , Staphylococcus aureus/genética
19.
Int J Infect Dis ; 84: 44-47, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31075509

RESUMO

The case of a patient with left ventricular assist device (LVAD)-associated endocarditis involving multiple clones of Staphylococcus aureus is presented. Different clones with distinct colony morphology were identified from blood cultures collected on the same day and showed diverse antimicrobial resistance patterns. In addition, a difference in antimicrobial susceptibility was observed even within an identical clone recovered 400 days apart due to the loss of SCCmec for methicillin and modification of the 23S rRNA target site for linezolid during a long-term treatment course.


Assuntos
Antibacterianos/farmacologia , Endocardite Bacteriana/etiologia , Ventrículos do Coração , Coração Auxiliar/efeitos adversos , Infecções Estafilocócicas/etiologia , Staphylococcus aureus , Antibacterianos/uso terapêutico , Endocardite Bacteriana/tratamento farmacológico , Endocardite Bacteriana/microbiologia , Humanos , Linezolida/uso terapêutico , Masculino , Staphylococcus aureus Resistente à Meticilina/genética , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , RNA Ribossômico 23S , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/genética
20.
BMC Infect Dis ; 19(1): 478, 2019 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-31142269

RESUMO

BACKGROUND: Staphylococcus aureus and beta-hemolytic streptococci (BHS) diseases disproportionately affect populations in middle/low-income countries. To assess if this disparity is reflected in colonization by these organisms, we compared their colonization frequency among children from different socioeconomic status (SES) communities in a city with high income inequality. METHODS: Between May-August 2014, we collected nasal and throat swabs to investigate S. aureus and BHS colonization among children who attended private and public pediatric clinics. Patients were classified as high SES, middle/low SES, and slum residents. We investigated the antimicrobial resistance profile, the SCCmec types and the presence of PVL genes among methicillin-resistant S. aureus (MRSA). We also examined the antimicrobial resistance profile and serogroups of BHS. RESULTS: Of 598 children, 221 (37%) were colonized with S. aureus, of which 49 (22%) were MRSA. MRSA colonization was higher in middle/low SES (n = 18; 14%) compared with high SES (n = 17; 6%) and slum (n = 14; 8%) residents (p = 0.01). All MRSA strains were susceptible to clindamycin, nitrofurantoin, and rifampin. The highest non-susceptibility frequency (42.9%) was observed to erythromycin. SCCmec type V was only found in isolates from high SES children; types I and II were found only in middle/low SES children. Ten (20%) MRSA isolates carried PVL genes. Twenty-four (4%) children were BHS carriers. All BHS (n = 8) found in high SES children and six (67%) isolates from slum patients belonged to group A. All group B streptococci were from middle/low SES children, corresponding to five (71%) of the seven BHS isolated in this group. BHS isolates were susceptible to all drugs tested. CONCLUSIONS: Children from different SES communities had distinct bacterial colonization profiles, including MRSA carriage. Public health officials/researchers should consider SES when assessing disease transmission and control measures.


Assuntos
Farmacorresistência Bacteriana , Infecções por Bactérias Gram-Positivas/diagnóstico , Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Criança , Pré-Escolar , Estudos Transversais , Farmacorresistência Bacteriana/efeitos dos fármacos , Feminino , Infecções por Bactérias Gram-Positivas/microbiologia , Humanos , Masculino , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/genética , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Testes de Sensibilidade Microbiana , Cavidade Nasal/microbiologia , Fatores de Risco , Fatores Socioeconômicos , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/genética , Staphylococcus aureus/isolamento & purificação , Streptococcus/efeitos dos fármacos , Streptococcus/genética , Streptococcus/isolamento & purificação
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA