Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 1.343
Filter
1.
Braz. j. biol ; 84: e253065, 2024. tab
Article in English | LILACS, VETINDEX | ID: biblio-1350311

ABSTRACT

Abstract Routine blood culture is used for the detection of bloodstream infections by aerobic and anaerobic bacteria and by common pathogenic yeasts. A retrospective study was conducted in a public hospital in Maceió-AL, by collecting data of all medical records with positive blood cultures. Out of the 2,107 blood cultures performed, 17% were positive with Staphylococcus coagulase negative (51.14%), followed by Staphylococcus aureus (11.21%) and Klebsiella pneumoniae (6.32%). Gram-positive bacteria predominated among positive blood cultures, highlighting the group of Staphylococcus coagulase-negative. While Gram-negative bacteria had a higher number of species among positive blood cultures.


Resumo A cultura sanguínea de rotina é usada para a detecção de infecções na corrente sanguínea por bactérias aeróbias e anaeróbias e por leveduras patogênicas comuns. Estudo retrospectivo realizado em hospital público de Maceió-AL, por meio da coleta de dados de todos os prontuários com culturas sanguíneas positivas. Das 2.107 culturas sanguíneas realizadas, 17% foram positivas com Staphylococcus coagulase negativo (51,14%), seguido por Staphylococcus aureus (11,21%) e Klebsiella pneumoniae (6,32%). As bactérias Gram-positiva predominaram entre as culturas de sangue positivas, destacando-se o grupo das Staphylococcus coagulase-negativo. Enquanto as bactérias Gram-negativas apresentaram um número maior de espécies entre as culturas de sangue positivas.


Subject(s)
Humans , Sepsis , Gram-Negative Bacteria , Brazil , Retrospective Studies , Hospitals
2.
Actual. SIDA. infectol ; 31(113): 11-18, 20230000. tab
Article in Spanish | LILACS, BINACIS | ID: biblio-1527283

ABSTRACT

Introducción: La emergencia y diseminación de la re-sistencia a antimicrobianos está vinculada en parte al abuso y/o mal uso de los mismos. La propagación del SARS-CoV-2 implicó un mayor consumo de antibióticos. El objetivo de este trabajo fue analizar los mecanismos de resistencia a betalactámicos (MRB) en bacilos Gram negativos (BGN) y la resistencia a amikacina (R AKN) en Acinetobacter baumannii.Métodos: Se realizó un estudio retrospectivo descriptivo de 2863 muestras con aislamientos de BGN remitidas al sector de Bacteriología del hospital de mayo 2019 a abril 2022. Se definieron tres períodos: mayo 2019-abril 2020 (P0), mayo 2020-abril 2021 (P1) y mayo 2021-abril 2022 (P2).Resultados: En P0 se halló un 15% de MRB. En P1, un 17,7% y en P2, un 21%. La combinación de BLEE+MBL se encontró en un aislamiento de P0, en dos de P1 y en 13 de P2. KPC+MBL se halló en nueve aislamientos de P2. La R AKN en A. baumannii fue de 20,8% en P0, 29,8% en P1 y 42,7% en P2.Conclusiones: Hubo un aumento significativo de aisla-mientos de BGN con MRB. BLEE fue el MRB más frecuente y Klebsiella sp. el microorganismo con MRB aislado con mayor frecuencia. En P2 se observó un aumento de aisla-mientos con combinación de MRB. Se observó diferencia significativa en la R AKN en A. baumannii entre P0 y P2. Con la pandemia de COVID-19 aumentó la cantidad de BGN con MRB y la R AKN en A. baumannii


Introduction: emergency and disemination of antimicrobial resistance is partly linked to abusive or wrong usage of them. The spread of SARS-CoV-2 implied a rise in antibiotics consumption. The aim of this study was to analize the mechanisms of resistance to beta lactams (MRB) in Gram negative bacilli (BGN) and amikacin resistance (R AKN) in Acinetobacter baumannii.Methods: a retrospective, descriptive study was made on 2863 samples with BGN isolates which were remitted to the bacteriology laboratory from May 2019 to April 2022. 3 periods were defined: May 2019 - April 2020 (P0). May 2020 - April 2021 (P1) and May 2021 - April 2022 (P2).Results: in P0, 15% had MRB. In P1, 17,7% and in P2, 21%. Combination of BLEE+MBL was found in 1 isolate of P0, in 2 of P1 and in 13 of P2. KPC+MBL was found in 9 isolates of P2. R AKN in A. baumannii was 20.8% in P0, 29.8% in P1 and 42.7% in P2.Conclusion: there was a significant increase in BGN isolates with MRB. BLEE was the most frequent MRB and Klebsiella sp. the most frequently isolated microorganism with MRB. A significant difference was observed in R AKN in A. baumanii between P0 and P2. After COVID-19 pandemic, there was an increase in the number of BGN with MRB and in R AKN in A. baumannii


Subject(s)
Humans , Male , Female , Drug Resistance , COVID-19 , Gram-Negative Bacteria , Anti-Infective Agents/therapeutic use
3.
Chinese Journal of Biotechnology ; (12): 1314-1331, 2023.
Article in Chinese | WPRIM | ID: wpr-981140

ABSTRACT

Stenotrophomonas species are non-fermentative Gram-negative bacteria that are widely distributed in environment and are highly resistant to numerous antibiotics. Thus, Stenotrophomonas serves as a reservoir of genes encoding antimicrobial resistance (AMR). The detection rate of Stenotrophomonas is rapidly increasing alongside their strengthening intrinsic ability to tolerate a variety of clinical antibiotics. This review illustrated the current genomics advances of antibiotic resistant Stenotrophomonas, highlighting the importance of precise identification and sequence editing. In addition, AMR diversity and transferability have been assessed by the developed bioinformatics tools. However, the working models of AMR in Stenotrophomonas are cryptic and urgently required to be determined. Comparative genomics is envisioned to facilitate the prevention and control of AMR, as well as to gain insights into bacterial adaptability and drug development.


Subject(s)
Stenotrophomonas/genetics , Drug Resistance, Bacterial/genetics , Anti-Bacterial Agents/pharmacology , Gram-Negative Bacteria , Genomics , Microbial Sensitivity Tests
4.
Journal of Experimental Hematology ; (6): 568-574, 2023.
Article in Chinese | WPRIM | ID: wpr-982096

ABSTRACT

OBJECTIVE@#To investigate the distribution and drug sensitivity of pathogenic bacteria isolated from patients in hematology department, in order to provide evidence for rational use of antibiotics in clinic.@*METHODS@#The distribution of pathogenic bacteria and drug sensitivity data of patients in the hematology department of The First Affiliated Hospital of Nanjing Medical University from 2015 to 2020 were retrospectively analyzed, and the pathogens isolated from different specimen types were compared.@*RESULTS@#A total of 2 029 strains of pathogenic bacteria were isolated from 1 501 patients in the hematology department from 2015 to 2020, and 62.2% of which were Gram-negative bacilli, mainly Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Stenotrophomonas maltophilia and Acinetobacter baumannii. Gram-positive coccus accounted for 18.8%, mainly Coagulase-negative staphylococcus (CoNS) and Staphylococcus aureus. Fungi (17.4%) were mainly candida. The 2 029 strains were mainly isolated from respiratory tract (35.1%), blood (31.8%) and urine (19.2%) specimens. Gram-negative bacilli were the main pathogenic bacteria in different specimen types (>60%). K. pneumoniae, S. maltophilia and A. baumannii were the most common pathogens in respiratory specimens, E. coli, CoNS, K. pneumoniae and P. aeruginosa were common in blood samples, and E. coli and Enterococcus were most common in urine samples. Enterobacteriaceae had the highest susceptibility to amikacin and carbapenems (>90.0%), followed by piperacillin/tazobactam. P. aeruginosa strains had high sensitivity to antibiotics except aztreonam (<50.0%). The susceptibility of A. baumannii to multiple antibiotics was less than 70.0%. The antimicrobial resistance rates of E. coli and K. pneumoniae in respiratory tract specimens were higher than those in blood specimens and urine specimens.@*CONCLUSION@#Gram-negative bacilli are the main pathogenic bacteria isolated from patients in hematology department. The distribution of pathogens is different in different types of specimens, and the sensitivity of each strain to antibiotics is different. The rational use of antibiotics should be based on different parts of infection to prevent the occurrence of drug resistance.


Subject(s)
Humans , Escherichia coli , Retrospective Studies , Bacteria , Anti-Bacterial Agents/therapeutic use , Gram-Negative Bacteria , Drug Resistance , Pseudomonas aeruginosa , Hematology
5.
Braz. j. biol ; 83: e248063, 2023. tab, graf
Article in English | LILACS, VETINDEX | ID: biblio-1339340

ABSTRACT

Abstract Persea lingue Ness is a tree species that lives mainly in temperate forests of south-central Chile. Its leaves are used in ethnomedicine, the fruit is a drupe similar to that of the avocado and has not been studied. The aim of this study was to determine the cytotoxicity in leukemia cell and antibacterial activity, along with some chemical content characteristics of P. lingue fruit and leaf extracts. The antibacterial activity was determined by the inhibition of bacterial growth in liquid medium assay against Gram-positive and Gram-negative bacteria. The leukemia cell lines Kasumi-1 and Jurkat were used to evaluate the cytotoxic activity by using propidium iodide and AlamarBlue assays. Total phenolic, flavonoid, condensed tannin, alkaloid and lipid contents were evaluated in the fruit and in the leaf extracts. The antioxidant activity of both extracts were also elavaluated. Leaf extract presented the highest content of total phenols, condensed tannins and flavonoids, and also the highest antioxidant activity. While the fruit extract has a higher amount of lipids and alkaloids and the high antibacterial activity against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus megaterium and Micrococcus luteus. The leaf extract only showed activity against M. luteus. Concerning the cytotoxic activity, only the fruit extract showed cytotoxicity against the cell lines Jurkat and Kasumi-1. P. lingue fruit extract is a potential source of biologically active molecules for the development of new drugs to be used in some types of leukemia, as well as antibacterial agent.


Resumo Persea lingue Ness é uma árvore que vive principalmente na floresta temperada do centro-sul do Chile. As folhas são usadas na etnomedicina. O fruto é uma drupa similar ao abacate e que nunca foi pesquisada anteriormente. O objetivo deste estudo foi o de avaliar a citotoxicidade em células leucêmicas e as atividades antibacterianas, assim como algumas características químicas do extrato de fruto e da folha do P. lingue. As atividades antibacterianas foram determinadas pelo método da inibição do crescimento bacteriano em meio líquido empregando-se bactérias Gram-positivas e Gram-negativas. As linhagens celulares leucêmicas, Kasumi-1 e Jurkat foram usadas para avaliar a atividade citotóxica em ensaios empregando-se iodeto de propídio e AlamarBlue. Foram avaliados os teores totais de fenóis, flavonóides, taninos condensados, alcalóides e lipídeos presentes nos extratos das folhas e dos frutos. As atividades antioxidantes de ambos os extratos também foram avaliadas. O extrato das folhas foi o que apresentou o maior conteúdo de fenóis, taninos condensados e flavonóides totais e a maior atividade antioxidante. Já o extrato de fruto apresentou a maior quantidade de lipídios e alcaloides e a melhor atividade antibacteriana contra Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus megaterium e Micrococcus luteus. Já o extrato das folhas apresentou apenas atividade contra M. luteus. Em relação à atividade citotóxica, apenas o extrato do fruto apresentou citotoxicidade contra as linhagens celulares Jurkat e Kasumi-1. Em resumo, o extrato do fruto de P. lingue é uma potencial fonte de moléculas com atividade biológica para o desenvolvimento de novos fármacos a serem utilizados em alguns tipos de leucemia, bem como agente antibacteriano.


Subject(s)
Lauraceae , Persea , Plant Extracts/pharmacology , Fruit , Gram-Negative Bacteria , Gram-Positive Bacteria , Anti-Bacterial Agents/pharmacology
6.
Braz. j. biol ; 83: e239323, 2023. tab, graf
Article in English | LILACS, VETINDEX | ID: biblio-1339341

ABSTRACT

Abstract The β-lactam/lactamase inhibitors (BLBLIs) combination drugs are considered an effective alternative to carbapenems. However, there is a growing concern that the increased use of BLBLIs may lead to increased resistance. This study determined the temporal association between the consumption of BLBLI and the antimicrobial resistance in Gram-negative bacteria. In this retrospective study, electronic data on the Gram-negative bacterial isolates, including A. baumannii, P. aeruginosa, E. coli, and K. pneumoniae from in-patients and susceptibility testing results were retrieved from the medical records of the clinical laboratory. A linear regression and cross-correlation analysis were performed on the acquired data. Increasing trends (p<0.05) in the consumption of BIBLI and carbapenem with a median use of 27.68 and 34.46 DDD/1000 PD per quarter were observed, respectively. A decreased trend (p=0.023) in the consumption of fluoroquinolones with a median use of 29.13 DDD/1000 PD per quarter was observed. The resistance rate of K. pneumoniae was synchronized with the BIBLI and carbapenem consumptions with a correlation coefficient of 0.893 (p=0.012) and 0.951 (p=0.016), respectively. The cross-correlation analysis against the consumption of BIBLI and meropenem resistant K. pneumoniae was peaked at 0-quarter lag (r=951, p=0.016). There was an increasing trend in the consumption of BLBLI and carbapenems. The increasing trend in the rates of resistance to piperacillin/tazobactam, in line with the increasing consumption of BLBLI, suggests that BLBLI has to be used with caution and cannot be directly considered as a long-term alternative to carbapenems.


Resumo Os medicamentos combinados de β-lactâmicos / inibidores da lactamase (BLBLIs) são considerados uma alternativa eficaz aos carbapenêmicos. No entanto, existe uma preocupação crescente de que o aumento do uso de BLBLIs pode levar ao aumento da resistência. Este estudo determinou a associação temporal entre o consumo de BLBLI e a resistência antimicrobiana em bactérias gram-negativas. Neste estudo retrospectivo, os dados eletrônicos sobre as bactérias gram-negativas isoladas, incluindo A. baumannii, P. aeruginosa, E. coli e K. pneumoniae de pacientes internados e os resultados dos testes de suscetibilidade foram recuperados dos registros médicos do laboratório clínico. Uma regressão linear e análise de correlação cruzada foram realizadas nos dados adquiridos. Foram observadas tendências crescentes (p < 0,05) no consumo de BIBLI e carbapenem com uma mediana de uso de 27,68 e 34,46 DDD/1000 PD por trimestre, respectivamente. Foi observada uma tendência de diminuição (p = 0,023) no consumo de fluoroquinolonas com uma mediana de uso de 29,13 DDD/1000 PD por trimestre. A taxa de resistência de K. pneumoniae foi sincronizada com os consumos de BIBLI e carbapenem com coeficiente de correlação de 0,893 (p = 0,012) e 0,951 (p = 0,016), respectivamente. A análise de correlação cruzada contra o consumo de BIBLI e K. pneumoniae resistente ao meropenem atingiu o pico no intervalo de 0 quarto (r = 951, p = 0,016). Houve uma tendência de aumento no consumo de BLBLI e carbapenêmicos. A tendência crescente nas taxas de resistência a piperacilina/tazobactam, em linha com o consumo crescente de BLBLI, sugere que BLBLI deve ser usado com cautela e não pode ser considerado diretamente como alternativa de longo prazo aos carbapenêmicos.


Subject(s)
Humans , Gram-Negative Bacterial Infections , Gram-Negative Bacterial Infections/epidemiology , Anti-Bacterial Agents/therapeutic use , Microbial Sensitivity Tests , Retrospective Studies , Escherichia coli , Gram-Negative Bacteria
7.
Journal of Experimental Hematology ; (6): 274-279, 2023.
Article in Chinese | WPRIM | ID: wpr-971136

ABSTRACT

OBJECTIVE@#To analyze the distribution and drug resistance of pathogens in oral mucositis associated with chemotherapy in hospitalized patients with malignant hematopathy, so as to provide scientific evidences for rational selection of antibiotics and infection prevention and control.@*METHODS@#From July 2020 to June 2022, 167 patients with malignant hematopathy were treated with chemical drugs in the Department of Hematology, Hainan Hospital, and secretions from oral mucosal infected wounds were collected. VITEK2 COMPECT automatic microbial identification system (BioMerieux, France) and bacterial susceptibility card (BioMerieux) were used for bacterial identification and drug susceptibility tests.@*RESULTS@#A total of 352 strains of pathogens were isolated from 167 patients, among which 220 strains of Gram-positive bacteria, 118 strains of Gram-negative bacteria and 14 strains of fungi, accounted for 62.50%, 33.52% and 3.98%, respectively. The Gram-positive bacteria was mainly Staphylococcus and Streptococcus, while Gram-negative bacteria was mainly Klebsiella and Proteus. The resistance of main Gram-positive bacteria to vancomycin, ciprofloxacin and gentamicin was low, and the resistance to penicillin, cefuroxime, ampicillin, cefotaxime, erythromycin and levofloxacin was high. The main Gram-negative bacteria had low resistance to gentamicin, imipenem and penicillin, but high resistance to levofloxacin, cefotaxime, cefuroxime, ampicillin and vancomycin. The clinical data of oral mucositis patients with oral ulcer (severe) and without oral ulcer (mild) were compared, and it was found that there were statistically significant differences in poor oral hygiene, diabetes, sleep duration less than 8 hours per night between two groups (P<0.05).@*CONCLUSION@#Gram-positive bacteria is the main pathogen of oral mucositis in patients with malignant hematopathy after chemotherapy. It is sensitive to glycopeptide antibiotics and aminoglycosides antibiotics. Poor oral hygiene, diabetes and sleep duration less than 8 hours per night are risk factors for oral mucositis with oral ulcer (severe).


Subject(s)
Humans , Vancomycin/therapeutic use , Cefuroxime , Levofloxacin , Oral Ulcer/drug therapy , Drug Resistance, Bacterial , Anti-Bacterial Agents/adverse effects , Ampicillin , Penicillins , Cefotaxime , Gram-Positive Bacteria , Gram-Negative Bacteria , Gentamicins , Stomatitis/drug therapy
8.
Chinese Journal of Hematology ; (12): 479-483, 2023.
Article in Chinese | WPRIM | ID: wpr-984647

ABSTRACT

Objective: To study the incidence of bloodstream infections, pathogen distribution, and antibiotic resistance profile in patients with hematological malignancies. Methods: From January 2018 to December 2021, we retrospectively analyzed the clinical characteristics, pathogen distribution, and antibiotic resistance profiles of patients with malignant hematological diseases and bloodstream infections in the Department of Hematology, Nanfang Hospital, Southern Medical University. Results: A total of 582 incidences of bloodstream infections occurred in 22,717 inpatients. From 2018 to 2021, the incidence rates of bloodstream infections were 2.79%, 2.99%, 2.79%, and 2.02%, respectively. Five hundred ninety-nine types of bacteria were recovered from blood cultures, with 487 (81.3%) gram-negative bacteria, such as Klebsiella pneumonia, Escherichia coli, and Pseudomonas aeruginosa. Eighty-one (13.5%) were gram-positive bacteria, primarily Staphylococcus aureus, Staphylococcus epidermidis, and Enterococcus faecium, whereas the remaining 31 (5.2%) were fungi. Enterobacteriaceae resistance to carbapenems, piperacillin/tazobactam, cefoperazone sodium/sulbactam, and tigecycline were 11.0%, 15.3%, 15.4%, and 3.3%, with a descending trend year on year. Non-fermenters tolerated piperacillin/tazobactam, cefoperazone sodium/sulbactam, and quinolones at 29.6%, 13.3%, and 21.7%, respectively. However, only two gram-positive bacteria isolates were shown to be resistant to glycopeptide antibiotics. Conclusions: Bloodstream pathogens in hematological malignancies were broadly dispersed, most of which were gram-negative bacteria. Antibiotic resistance rates vary greatly between species. Our research serves as a valuable resource for the selection of empirical antibiotics.


Subject(s)
Humans , Bacteremia/epidemiology , Cefoperazone , Sulbactam , Retrospective Studies , Drug Resistance, Bacterial , Microbial Sensitivity Tests , Hematologic Neoplasms , Sepsis , Anti-Bacterial Agents/pharmacology , Gram-Negative Bacteria , Gram-Positive Bacteria , Piperacillin, Tazobactam Drug Combination , Escherichia coli
9.
Arq. ciências saúde UNIPAR ; 26(2): 135-145, maio-ago. 2022.
Article in Portuguese | LILACS | ID: biblio-1372966

ABSTRACT

A meningite bacteriana é uma inflamação das leptomeninges que envolvem o Sistema Nervoso Central. Essa patologia, que possui diversos agentes etiológicos, apresenta-se na forma de síndrome, com quadro clínico grave. Entre as principais bactérias que causam a meningite, estão a Neisseria meningitis e Streptococcus pneumoniae. A transmissão ocorre através das vias aéreas por meio de gotículas, sendo a corrente sanguínea a principal rota para as bactérias chegarem à barreira hematoencefálica e, a partir dessa, até as meninges. Atualmente existem vários métodos de diagnóstico precisos, onde a cultura de líquido cefalorraquidiano (LCR) é o método padrão ouro. Ademais, a melhora na qualidade do tratamento com beta-lactâmicos e a maior possibilidade de prevenção, devido à elevação do número e da eficácia de vacinas, vem contribuindo para redução dos casos da doença e de sua gravidade. Porém, apesar desses avanços, ainda há um elevado número de mortalidades e sequelas causadas por essa síndrome.


Bacterial meningitis is an inflammation of the leptomeninges that surround the Central Nervous System. This pathology, which has several etiological agents, is presented as a syndrome with a severe clinical scenario. The main bacteria causing meningitis include Neisseria meningitis and Streptococcus pneumoniae. It can be transmitted by droplets through the airways, with the bacteria using the bloodstream as the main route to reach the blood-brain barrier, and from there to the meninges. There are currently several accurate diagnostic methods, with CSF culture being the gold standard. In addition, the improvement in the quality of beta-lactam treatment and the greater possibility of prevention due to the increased number and effectiveness of vaccines have contributed to reducing the number of cases and severity of the disease. Nevertheless, despite these advances, this syndrome still presents a high number of mortalities and sequelae.


Subject(s)
Pregnancy , Child, Preschool , Child , Aged , Cerebrospinal Fluid , Meningitis, Bacterial/diagnosis , Meningitis, Bacterial/therapy , Streptococcus pneumoniae/pathogenicity , Syndrome , Bacteria/classification , Meningitis, Bacterial/drug therapy , beta-Lactams/therapeutic use , Gram-Negative Bacteria , Gram-Positive Bacteria , Meningitis, Pneumococcal/drug therapy , Neisseria/pathogenicity
10.
Biomédica (Bogotá) ; 42(1): 54-66, ene.-mar. 2022. tab, graf
Article in Spanish | LILACS | ID: biblio-1374507

ABSTRACT

Introducción. La creciente resistencia bacteriana a los antibióticos representa una amenaza mundial de salud pública. Las excreciones y secreciones larvarias derivadas de moscas necrófagas de la familia Calliphoridae podrían configurar una fuente promisoria para contrarrestar sus efectos. Objetivo. Comparar la actividad antimicrobiana de las excreciones y secreciones larvarias nativas, y de las mayores y menores de 10 kDa de Calliphora vicina y Sarconesiopsis magellanica (Diptera: Calliphoridae). Materiales y métodos. El bioensayo se hizo a partir de la técnica de turbidimetría y en el caso de las excreciones y secreciones menores de 10 kDa se determinó la concentración inhibitoria mínima (CIM). Resultados. Las excreciones y secreciones nativas y las menores de 10 kDa de C. vicina y S. magellanica, evidenciaron una potente actividad antibacteriana contra tres cepas de Staphylococcus aureus y cuatro bacterias Gram negativas, siendo las menores de 10 kDa más efectivas que las nativas en las dos especies de moscas evaluadas. Además, las menores de 10 kDa presentaron la misma efectividad, aunque en las pruebas de CIM se observó que las de S. magellanica fueron más potentes en todas las bacterias evaluadas, excepto contra la cepa de S. aureus ATCC 25923. Las mayores de 10 kDa no inhibieron el crecimiento bacteriano. Conclusión. Los resultados validaron, en general, que estas sustancias son fuente importante para el aislamiento y la caracterización de agentes antimicrobianos.


Introduction: The growing resistance to antibiotics worldwide represents a global threat to public health. The larval excretions and secretions derived from necrophagous flies from the Calliphoridae family could represent a promising source for counteracting their effects. Objective: To compare the antimicrobial activity of Calliphora vicina and Sarconesiopsis magellanica (Diptera: Calliphoridae) native excretions and secretions and those weighing more than 10 kDa and less. Materials and methods: We used the turbidimetry technique for the bioassay; we determined the minimum inhibitory concentration (MIC) for excretions and secretions weighing less than 10 kDa. Results: Calliphora vicina and S. magellanica native excretions and secretions and those weighing less than 10 kDa exhibited potent antibacterial activity against three Staphylococcus aureus strains and four Gram-negative bacteria; those weighing less than 10 kDa were more effective than the native ones in the two species of flies evaluated here. Furthermore, excretions and secretions weighing less than 10 kDa had the same effectiveness, except in the MIC trials where S. magellanica excretions and secretions weighing less than 10 kDa were more potent against all the bacteria evaluated, except for S. aureus ATCC 25923. Excretions and secretions weighing more than 10 kDa did not inhibit bacterial growth. Conclusions: These results potentially validate these substances as an important source for isolating and characterizing antimicrobial agents.


Subject(s)
Modalities, Secretion and Excretion , Diptera , Gram-Negative Bacteria , Gram-Positive Bacteria , Larva , Anti-Bacterial Agents
11.
Article in Spanish | LILACS, CUMED | ID: biblio-1408435

ABSTRACT

Introducción: Los mapas microbiológicos se consideran un marcador epidemiológico pues resumen estadísticamente las bacterias circulantes y su comportamiento frente a los antibióticos en uso. Permiten establecer una política de antibióticos que garantiza el uso más racional de los antimicrobianos y disminuye el riesgo de resistencia bacteriana. Objetivos: Identificar las bacterias aisladas con mayor frecuencia a partir de cultivos microbiológicos de pacientes hospitalizados en el Instituto de Hematología e Inmunología durante el año 2020 y determinar la resistencia de las bacterias más frecuentes a los antimicrobianos ensayados, con vista a establecer el primer mapa microbiológico de la institución. Métodos: Se realizó un estudio de corte transversal que incluyó los cultivos de pacientes hospitalizados durante el año 2020. La identificación bacteriana se realizó según métodos convencionales y para determinar los perfiles de resistencia se empleó el método de Bauer-Kirby. Resultados: El hemocultivo fue el estudio microbiológico más indicado con una positividad de 32,80 por ciento. Predominaron las bacterias Gram negativas (81,71 por ciento), siendo las más identificadas Pseudomonas spp., Enterobacter spp., Klebsiella spp. y Escherichia coli. Entre las bacterias Gram positivas predominó Staphylococcus spp. coagulasa negativa. Se obtuvieron elevados porcentajes de resistencia frente a casi todos los antimicrobianos evaluados. Conclusiones: La realización del mapa microbiológico de la institución permite actualizar la política de uso de los antimicrobianos al identificar a los bacilos Gram negativos, con elevados porcentajes de resistencia, como los principales agentes etiológicos de las infecciones registradas en este centro de salud durante el año 2020(AU)


Introduction: Microbiological maps are considered an epidemiological marker as statistically summarize circulating bacteria and their behavior against antibiotics in use. They allow establishing an antibiotic policy that guarantees the most rational use of antimicrobials and decreases the risk of bacterial resistance. Objectives: Identify the isolated bacteria with more frequency from microbiological crops of hospitalized patients in the Institute of Hematology and Immunology during the year 2020 and determine the resistance of the most frequent bacteria to the antimicrobials tested, with a view to establishing the first microbiological map of the institution. Methods: An observational, descriptive, cross-sectional study was performed that included cultures of patients hospitalized during the year 2020. Bacterial identification was carried out according to conventional methods and to determine the resistance profiles was used by the Bauer-Kirby method. Results: The blood culture was the most indicated microbiological study with 32.80 percent positivity. The Gram negative bacteria predominated (81.71percent), being the most identified Pseudomona spp., Enterobacter spp., Klebsiella spp. and Escherichia coli. Among the Gram positive bacteria predominate Staphylococcus spp. coagulase negative. High percentages of resistance were obtained in front of almost all antimicrobials evaluated. Conclusions: The completion of the institutional microbiological map allows updating the antimicrobial use policy by identifying the Gram negative bacilli, with high percentages of resistance, as the main etiological agents of the infections registered in this health center during 2020(AU)


Subject(s)
Humans , Male , Female , Health Centers , Allergy and Immunology , Gram-Negative Bacteria , Hematology , Anti-Infective Agents
12.
Rev. bras. anal. clin ; 54(1): 50-54, 20220330.
Article in Portuguese | LILACS | ID: biblio-1395668

ABSTRACT

Serratia marcescens pertence à Família Enterobacteriaceae, é Gram-negativa e anaeróbica facultativa, sendo bem distribuída na natureza; pode ser isolada como saprófita do solo e da água. Possui um significado clínico relevante, pois acarreta infecções nosocomiais e pulmonares em determinados setores da saúde, como unidades neonatais, maternidades e UTIs, além de sepse, meningite, choque endotóxico e infecções do trato urinário. O intuito desse estudo foi analisar o mecanismo de heterorresistência em linhagens sensíveis de Serratia marcescens diante das concentrações testadas de meropeném. As linhagens SR1 e SR2 apresentaram perfil heterorresistente, ao passo que a SR6 demonstrou ser não heterorresistente, com CIM elevado (32µg/mL). Os isolados de Serratia marcescens são suscetíveis ao meropenem, por testes de sensibilidade padrão, mas contêm subpopulações resistentes ao mesmo.


Serratia marcescens belongs to the Enterobacteriaceae family, it is optional anaerobic gram-negative, being well distributed in nature and it might be isolated as saprophytic from soil and water. It has a meaningful clinical significance, because it causes nosocomial and lung infections in certain healthcare sectors, such as neonatal units, maternity units and UTIs; septicemia, meningitis, endotoxin shock and urinary tract infections. The aim of this study was to analyze the mechanism of heteroresistance in susceptible strains of Serratia marcescens in the presence of the tested concentration of meropenem. The lineages SR1 and SR2 presented heteroresistant profile, while the SR6 showed to be nonheterorresistente, with CIM (32 µg/mL). The Isolates of Serratia marcescens are susceptible to meropenem, by standard sensitivity testing, but there are subpopulations resistant to it.


Subject(s)
Serratia Infections , Drug Resistance, Bacterial , Carbapenem-Resistant Enterobacteriaceae , Serratia marcescens , Enterobacteriaceae , Meropenem , Gram-Negative Bacteria
13.
Journal of Experimental Hematology ; (6): 201-205, 2022.
Article in Chinese | WPRIM | ID: wpr-928693

ABSTRACT

OBJECTIVE@#To explore the characteristics of infection in patients with myelodysplastic syndromes (MDS), risk factors of serious infection, and their correlation with curative effect.@*METHODS@#The clinical data of 92 newly diagnosed MDS patients with nosocomial infection from January 2016 to June 2020 in our hospital were retrospectively analyzed.@*RESULTS@#A total of 306 courses of treatment were completed in 92 newly diagnosed MDS patients. The infection rate was the highest in the first course of treatment (84.8%, 78/92), and then decreased gradually. The top three infection sites were lung, upper respiratory tract, and gastrointestinal tract. A total of 90 strains of pathogenic bacteria were detected, of which 33.4% (30/90) were gram-negative bacilli, 23.3% (21/90) were gram-positive cocci, 23.3% (21/90) were fungi, and 20.0% (18/90) were viruses. The serious infection rate among 92 patients with MDS was 22.8% (21/92). Multivariate analysis showed that neutrophil deficiency>7 days (OR=10.875, 95%CI: 2.747-43.051, P=0.001) was an independent risk factor for serious infection in MDS patients. Compared with non-severe infection group, the total effective rate of severe infection group was lower (90.9% vs 63.6%, χ2=4.393, P<0.05).@*CONCLUSION@#The infection rate of MDS patients is high in the first course of treatment, and the most common infection site is the lung. Gram-negative bacteria is the most common pathogen. MDS patients with neutrophil deficiency>7 days have a high risk of serious infection and poor efficacy.


Subject(s)
Humans , Cross Infection , Gram-Negative Bacteria , Myelodysplastic Syndromes , Retrospective Studies , Risk Factors
14.
Braz. j. biol ; 82: e233523, 2022. tab
Article in English | LILACS, VETINDEX | ID: biblio-1153470

ABSTRACT

Microbiological studies of the sanitary and health status of psittacine birds that will be reintroduced is important in evaluating whether these animals act as carriers of pathogenic agents to other animals and humans. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is a faster and more accurate method to identify bacteria than conventional microbiology methods. The aim of this study was to evaluate the health status of psittacines housed in captivity, by assessment of Gram-negative bacteria from fecal microbiota through MALDI- TOF MS identification. The results indicate high frequency of Gram-negative bacteria in feces (96.5%), especially from the Enterobacteriaceae family (88.7%). The most prevalent bacteria were Escherichia coli (39.0%), Proteus vulgaris (12.2%), Klebsiella spp. (12.1%) and Raoultella ornithinolytica (8.7%). Proteus hauseri, Citrobacter spp., Morganella morgannii, Providencia rettgeri, Enterobacter spp. and Escherichia hermannii were isolated with lower frequency. . All these agents are potentially pathogenic for parrots and can cause systemic infections in other animals and humans. These findings reinforce that MALDI- TOF MS proved to be a rapid and accurate method of identification of the microorganism and evaluation of the health status of psittacines, providing relevant data to assist decision-making regarding the sanitary protocols in wildlife centers, and possible future reintroduction of wild birds.


Estudos microbiológicos da sanidade de psitacídeos que serão reintroduzidos são importantes para avaliar se esses animais atuam como portadores de agentes patogênicos para outros animais e humanos. A espectrometria de massa por ionização/dessorção de matriz assistida por laser/tempo de vôo (MALDI-TOF MS) é um método mais rápido e preciso para identificar bactérias na comparação com métodos convencionais de microbiologia. O objetivo deste estudo foi avaliar o estado de saúde de psitacídeos cativos, identificando bactérias Gram-negativas da microbiota fecal por MALDI -TOF MS. Os resultados indicaram alta frequência de bactérias Gram-negativas nas fezes (96,5%), principalmente da família Enterobacteriaceae (88,7%). As mais prevalentes foram Escherichia coli (39,0%), Proteus vulgaris (12,2%), Klebsiella spp. (12,1%) e Raoultella ornithinolytica (8,7%). Proteus hauseri, Citrobacter spp., Morganella morgannii, Providencia rettgeri, Enterobacter spp. e Escherichia hermannii foram isolados com menor frequência. Todos esses agentes são potencialmente patogênicos para os papagaios e podem causar infecções sistêmicas em outros animais e seres humanos. Esses achados reforçam que o MALDI- TOF MS é um método rápido e preciso de identificação do microrganismo e avaliação do estado de saúde dos psitacídeos, fornecendo dados relevantes para auxiliar na tomada de decisões sobre os protocolos sanitários em centros de triagem de animais selvagens e sobre a possibilidade de reintrodução futura.


Subject(s)
Humans , Animals , Psittaciformes , Gram-Negative Bacteria , Proteus , Providencia , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization , Enterobacteriaceae
15.
Braz. j. biol ; 82: 1-9, 2022. map, ilus, tab
Article in English | LILACS, VETINDEX | ID: biblio-1468416

ABSTRACT

Use of antibiotics inevitably leads to antimicrobial resistance. Selection for resistance occurs primarily within the gut of humans and animals as well as in the environment through natural resistance and residual antibiotics in streams and soil. We evaluated antimicrobial resistance in Gram negative bacteria from a river system in a rural community in Bahia, Brazil. Water was collected from the Jiquiriçá and Brejões rivers and the piped water supply. Additionally, stools were collected from a random sample of residents, cows, pigs and horses near the river. The samples were screened for bacteria resistant to ciprofloxacin, cefotaxime, and meropenem and identified biochemically at the genus and species levels. Microbial source tracking demonstrated that ruminant and human fecal contamination increased as the rivers neared the village center and decreased after the last residence. Antibiotic bacteria were identified from all samples (n = 32). No bacteria were resistant to carbapenems, but the majority of the enterobacteria were resistant to ciprofloxacin, even though this class of antibiotics is not commonly used in food animals in this region. Considering these facts, together with the pattern of human fecal contamination, a human source was considered most likely for these resistant isolates.


O uso de antibióticos inevitavelmente leva à resistência antimicrobiana. A seleção para resistência antimicrobiana ocorre principalmente no intestino de seres humanos e animais, bem como no meio ambiente, através da resistência natural e resíduos de antibióticos nos esgotos e no solo. Avaliamos a resistência antimicrobiana em bactérias Gram-negativas de um sistema fluvial em uma comunidade rural da Bahia, Brasil. A água foi coletada nos rios Jiquiriçá e Brejões e no abastecimento de água encanada. Além disso, foram coletadas amostras randomizadas de fezes de moradores, vacas, porcos e cavalos próximos ao rio. As amostras foram triadas para bactérias resistentes à ciprofloxacina, cefotaxima e meropenem e identificadas bioquimicamente nos níveis de gênero e espécie. O rastreamento de fontes microbianas demonstrou que a contaminação fecal de ruminantes e humanos aumentou à medida que os rios se aproximavam do centro da vila e diminuía após a última residência. Bactérias resistentes a antibióticos foram identificadas em todas as amostras (n = 32). Nenhuma bactéria demonstrou ser resistente aos carbapenêmicos testados, contudo, foi encontrado enterobactérias resistentes à ciprofloxacina, ainda que essa classe de antibióticos não seja comumente usada na medicina veterinária dos animais dessa região. Considerando esses fatos, juntamente com o padrão de contaminação fecal avaliado, a fonte de contaminação humana foi considerada a mais provável na interação desses isolados resistentes.


Subject(s)
Gram-Negative Bacteria/pathogenicity , Enterobacteriaceae/pathogenicity , Drug Resistance, Bacterial , Feces/microbiology , Water Pollutants/analysis
16.
Braz. j. biol ; 82: 1-7, 2022. tab
Article in English | LILACS, VETINDEX | ID: biblio-1468437

ABSTRACT

Microbiological studies of the sanitary and health status of psittacine birds that will be reintroduced is important in evaluating whether these animals act as carriers of pathogenic agents to other animals and humans. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is a faster and more accurate method to identify bacteria than conventional microbiology methods. The aim of this study was to evaluate the health status of psittacines housed in captivity, by assessment of Gram-negative bacteria from fecal microbiota through MALDI- TOF MS identification. The results indicate high frequency of Gram-negative bacteria in feces (96.5%), especially from the Enterobacteriaceae family (88.7%). The most prevalent bacteria were Escherichia coli (39.0%), Proteus vulgaris (12.2%), Klebsiella spp. (12.1%) and Raoultella ornithinolytica (8.7%). Proteus hauseri, Citrobacter spp., Morganella morgannii, Providencia rettgeri, Enterobacter spp. and Escherichia hermannii were isolated with lower frequency. . All these agents are potentially pathogenic for parrots and can cause systemic infections in other animals and humans. These findings reinforce that MALDI- TOF MS proved to be a rapid and accurate method of identification of the microorganism and evaluation of the health status of psittacines, providing relevant data to assist decision-making regarding the sanitary protocols in wildlife centers, and possible future reintroduction of wild birds.


Estudos microbiológicos da sanidade de psitacídeos que serão reintroduzidos são importantes para avaliar se esses animais atuam como portadores de agentes patogênicos para outros animais e humanos. A espectrometria de massa por ionização/dessorção de matriz assistida por laser/tempo de vôo (MALDI-TOF MS) é um método mais rápido e preciso para identificar bactérias na comparação com métodos convencionais de microbiologia. O objetivo deste estudo foi avaliar o estado de saúde de psitacídeos cativos, identificando bactérias Gram-negativas da microbiota fecal por MALDI -TOF MS. Os resultados indicaram alta frequência de bactérias Gram-negativas nas fezes (96,5%), principalmente da família Enterobacteriaceae (88,7%). As mais prevalentes foram Escherichia coli (39,0%), Proteus vulgaris (12,2%), Klebsiella spp. (12,1%) e Raoultella ornithinolytica (8,7%). Proteus hauseri, Citrobacter spp., Morganella morgannii, Providencia rettgeri, Enterobacter spp. e Escherichia hermannii foram isolados com menor frequência. Todos esses agentes são potencialmente patogênicos para os papagaios e podem causar infecções sistêmicas em outros animais e seres humanos. Esses achados reforçam que o MALDI- TOF MS é um método rápido e preciso de identificação do microrganismo e avaliação do estado de saúde dos psitacídeos, fornecendo dados relevantes para auxiliar na tomada de decisões sobre os protocolos sanitários em centros de triagem de animais selvagens e sobre a possibilidade de reintrodução futura.


Subject(s)
Animals , Gram-Negative Bacteria/pathogenicity , Enterobacteriaceae/pathogenicity , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization , Parrots/microbiology
17.
Pesqui. vet. bras ; 42: e06990, 2022. tab, ilus
Article in English | LILACS, VETINDEX | ID: biblio-1365240

ABSTRACT

The current techniques used in the disinfection of reused poultry litter, such as lime addition, windrowing and plastic cover on the surface, do not guarantee the elimination of pathogenic microorganisms, causing damage to the environment and animal health. Gram negative bacteria, i.e., Salmonella and Escherichia coli, can be transmitted from one batch to another through reused litter, causing health damage to broilers and humans that consume food contaminated by these agents. Our study assessed the effectiveness of the methods plastic cover on the surface (PCS) and plastic cover on the surface with ammonia gas injection (PCSAI) in the control of Gram negative bacteria. The results obtained, both in laboratory conditions (Experiment 1) and in the field (Experiment 2), demonstrate that the method PCSAI with 0.22% ammonia gas had a significant reduction (P<0.05) of Gram negative bacteria in the period of 48 hours This new methodology for disinfecting poultry litter will allow its reuse in a practical and safe way, improving the preservation of the environment, of the health of broilers and consumers of poultry products.


O reaproveitamento de camas aviárias na criação de frangos de corte é uma prática muito utilizada no Brasil. Essa prática reduz custos de produção e contribui na conservação do meio ambiente. As técnicas atuais utilizadas na desinfecção de camas aviárias reaproveitadas, como adição de cal, enleiramento e lona na superfície, não garantem a eliminação de microrganismos patogênicos porque não geram quantidade suficiente de amônia. O gás amônia, em concentrações elevadas, tem efeito biocida. Bactérias Gram negativas, como as Salmonelas e Escherichia coli, podem ser transmitidas de um lote para outro através do reaproveitamento da cama, ocasionando prejuízos para a saúde das aves e dos humanos que consomem alimentos contaminados por estes agentes. Este trabalho avaliou a eficácia do método lona na superfície com injeção de gás amônia no controle de microrganismos Gram negativos. Os resultados obtidos demostraram que esse método controlou os microrganismos Gram negativos num período de 48 horas em camas de frangos de corte reaproveitadas. Assim, essa nova metodologia de desinfecção de camas de aviário permitirá sua reutilização de forma prática e segura, melhorando a saúde das aves e dos consumidores dos produtos avícolas.


Subject(s)
Animals , Poultry/microbiology , Chickens , Disinfection/methods , Ammonia/therapeutic use , Gram-Negative Bacteria
18.
Ciênc. cuid. saúde ; 21: e59515, 2022. tab
Article in Portuguese | LILACS, BDENF | ID: biblio-1404235

ABSTRACT

RESUMO Objetivo: analisar a infecção primária da corrente sanguínea associada ao cateter venoso central em neonatos internados em unidades de terapia intensiva. Método: tratou-se de um estudo ecológico realizado em 2017 a partir de notificações de infecção primária da corrente sanguínea associada ao cateter venoso central ocorridas na capital de um estado da região Centro-Oeste do Brasil. Os dados foram coletados por meio de um formulário a partir de dois bancos de dados, municipal (2012 a 2016) e nacional (2014 a 2016). Resultados: a tendência temporal da densidade de incidência de infecção foi decrescente (p=0,019), com taxa de utilização de cateter venoso central de 45%. Os patógenos mais frequentes foram Klebsiella pneumoniae, Staphylococcus coagulase negativo e Enterobacter spp. Aumento de resistência às cefalosporinas e à oxacilina ocorreu para bactérias Gram-negativo e Gram-positivo, respectivamente. Conclusão: Conclui-se que houve uma redução na taxa de IPCS associada ao cateter em neonatos no período avaliado e os episódios infecciosos foram predominantemente causados por bactérias Gram-negativo, incluindo isolados multirresistentes aos antimicrobianos. Esses achados apontam para a importância e necessidade de estratégias educacionais para a equipe multiprofissional sobre vigilância de infecção, medidas preventivas e uso racional de antimicrobianos.


Resumen: Objetivo: analizar la infección primaria del torrente sanguíneo asociada al catéter venoso central en neonatos ingresados en unidades de cuidados intensivos. Método: se trató de un estudio ecológico, realizado en 2017, a partir de notificaciones de infección primaria del torrente sanguíneo asociada al catéter venoso central, ocurridas en la capital de un estado de la región Centro-Oeste de Brasil. Los datos fueron recogidos por medio de un formulario de dos bases de datos, municipal (2012 a 2016) y nacional (2014 a 2016). Resultados: la tendencia temporal de la densidad de incidencia de infección fue decreciente (p=0,019), con tasa de utilización de catéter venoso central del 45%. Los patógenos más frecuentes fueron Klebsiella pneumoniae, Staphylococcus coagulase negativa y Enterobacter spp. Aumento de resistencia a las cefalosporinas y a la oxacilina ocurrió para bacterias Gramnegativas y Grampositivas, respectivamente. Conclusión: hubo una reducción en la tasa de infección primaria del torrente sanguíneo asociada al catéter en neonatos en el período evaluado, y los episodios infecciosos fueron predominantemente causados por bacterias gramnegativas, incluyendo aislados multirresistentes a los antimicrobianos. Estos hallazgos señalan la importancia y necesidad de estrategias educativas para el equipo multiprofesional sobre vigilancia de infecciones, medidas preventivas y uso racional de antimicrobianos.


ABSTRACT Objective: to analyze primary bloodstream infections associated with central venous catheter in neonates admitted to intensive care units. Method: ecological study, conducted in 2017, from reports of primary bloodstream infections associated with central venous catheter, which occurred in the capital of a state in the Midwest region of Brazil. Data were collected using a form from two databases, municipal (2012 to 2016) and national (2014 to 2016). Results: the temporal trend of the infection incidence density was decreasing (p=0.019), with a central venous catheter use rate of 45%. The most frequent pathogens were Klebsiella pneumoniae, Coagulase-negative staphylococci, and Enterobacter spp. Increased resistance to cephalosporins and oxacillin occurred for Gram-negative and Gram-positive bacteria, respectively. Conclusion: There was a reduction in the rate of catheter-associated primary bloodstream infection in neonates in the period evaluated, and the infectious episodes were predominantly caused by Gram-negative bacteria, including antimicrobial multi-resistant isolates. These findings point to the importance and need for educational strategies for the multiprofessional team on infection surveillance, preventive measures, and rational use of antimicrobials.


Subject(s)
Humans , Male , Female , Infant, Newborn , Blood Circulation , Infant, Newborn , Catheters , Central Venous Catheters , Infections , Oxacillin , Staphylococcus , Bacteria , Health Strategies , Sepsis , Cephalosporin Resistance , Gram-Negative Bacteria , Gram-Positive Bacteria , Intensive Care Units , Klebsiella pneumoniae , Anti-Infective Agents , Noxae
19.
Braz. J. Pharm. Sci. (Online) ; 58: e19898, 2022. tab, graf
Article in English | LILACS | ID: biblio-1394061

ABSTRACT

Abstract A study was carried out to synthesize silver nanoparticles (Ag-NPs) using plant extracts and to explore their pharmaceutical application as antibacterial agents. Dried leaves of Mentha arvensis Linn. were powdered and extracts were prepared using three different organic solvents. Preliminary screening on antibacterial activity by agar well diffusion method indicated that the methanolic extract possessed higher potential than the other two. Phytochemical analysis of the leaf extract revealed that it possesses tannins, steroids, terpenoids and flavonoids. Ag-NPs prepared using this extract were of spherical to cuboidal shape ranging in size from 40 to 70 nm. It retained essential chemical groups and had the required surface plasmon resonance. Further to the antimicrobial assay, the Ag-NPs, in contrast to the whole methanolic leaf extract, showed better (100% vs. 80%) bactericidal activity against the indicator organisms. The zones of growth inhibition for gram positive bacteria ranged between 14±0.6 and 23±0.3, while it was between 12±0.6 and 22±0.2 for gram negative bacteria. The Ag-NPs presented the minimum inhibitory concentration values of 250 µg/mL for gram positive bacteria and 250 - 500 µg/mL for gram negative bacteria. These findings suggest that the natural compounds present in M. arvensis L. possess the potency to facilitate the synthesis and antibacterial action of Ag-NPs.


Subject(s)
Silver , Plant Extracts/pharmacology , Mentha/chemistry , Nanoparticles , Gram-Negative Bacteria/drug effects , Gram-Positive Bacteria/drug effects , Anti-Bacterial Agents/pharmacology , Microbial Sensitivity Tests
20.
São Paulo; s.n; s.n; 2022. 78 p. tab, graf.
Thesis in Portuguese | LILACS | ID: biblio-1396415

ABSTRACT

Bactérias regulam a expressão de diversos fenótipos de acordo com a sua densidade populacional, em um comportamento conhecido como quorum sensing. Em micro-organismos de origem alimentar, o quorum sensing pode influenciar na formação de biofilmes, produção de toxinas e de enzimas hidrolíticas. Em bactérias Gram-negativas a sinalização é normalmente mediada por moléculas de N-acilhomoserina lactona (AHLs), conhecidas por autoindutor 1 (AI-1). Estudos revelam a inibição do quorum sensing nestas bactérias por enzimas que degradam as AHLS, em um processo denominado quorum quenching. Tipicamente brasileiro, o queijo Canastra é um produto artesanal maturado, produzido a partir de leite cru e do pingo, um tipo de soro-fermento coletado e utilizado diariamente na produção. A composição microbiana do pingo é diversificada e característica da região produtora. Essa combinação de bactérias, única em cada queijaria, resulta em aroma e textura típicos. Enquanto a microbiota Gram-positiva contribui para o desenvolvimento de sabor, textura e aroma no produto, bactérias Gram-negativas nesses queijos são geralmente associadas à formação de olhaduras, aromas desagradáveis, má coagulação da massa e até à patogenicidade. Este trabalho visou analisar a interação entre a microbiota Gram-positiva e Gram-negativa presente no pingo pela detecção dos sistemas de quorum sensing e quorum quenching nas amostras. A presença de AHLs foi avaliada em 45 amostras de pingo, a partir da extração em acetato de etila acidificado e da avaliação dos extratos por meio de bioensaios com Agrobacterium tumefaciens WCF47(pCF218)(pCF372) e KYC55(pJZ410)(pJZ372)(pJZ384), resultando em apenas uma amostra positiva. Em seguida, 350 isolados foram obtidos a partir de 11 amostras de pingo, sendo 200 isolados classificados como Gram-positivos e 150 Gram-negativos. Os Gramnegativos foram avaliados quanto à produção de AHLs in vitro através de ensaio em placa utilizando as estirpes biossensoras A. tumefaciens WCF47(pCF218)(pCF372), Chromobacterium violaceum CV026 e Escherichia coli pSB403, resultando em 39 isolados produtores de AHLs, provenientes de 10 pingos diferentes. Já os isolados Gram-positivos foram analisados quanto à capacidade de inibição do QS utilizando as estirpes biossensoras C. violaceum CV026 e A. tumefaciens WCF47(pCF218)(pCF372), em meio suplementado com C6-HSL ou 3-oxo-C12-HSL. Foi detectada a inibição total da resposta ao quórum por 78 isolados testados, enquanto a inibição parcial foi provocada por outros 63. A inibição do crescimento das estirpes biossensoras também foi observada para 24 isolados. Os isolados promotores de inibição parcial foram recultivados em meio mínimo com C6-HSL ou 3-oxo-C12-HSL como únicas fontes de carbono. Foram recuperados 28 isolados, e a ação desses sobre diferentes substratos foi avaliada, resultando em 22 isolados produtores de lactonases e 6 produtores de acilase. Os 39 isolados Gram-negativos e os 28 isolados Gram-positivos finais foram identificados por MALDI-TOF MS, resultando, segundo o conhecimento do autor, no primeiro relato de produção de AHLs por Pseudomonas fulva, Enterobacter xiangfangensis e Lelliottia amnigena, bem como a produção de lactonases por Staphylococcus xylosus e a produção de acilase por S. aureus, Microbacterium maritypicum e Rothia kristinae. Este trabalho mostrou que interações populacionais mediadas por quorum sensing dependente de AHLs na microbiota do soro-fermento são possíveis. Porém, essas interações estão propensas a serem inibidas por meio de lactonases e acilases produzidas por parte das bactérias Gram-positivas


Bacteria regulate the expression of different phenotypes according to their population density, in a behavior known as quorum sensing. In food-borne microorganisms, quorum sensing can influence the formation of biofilms, production of toxins and hydrolytic enzymes. In Gram-negative bacteria, signaling is normally mediated by Nacyl homoserine lactone molecules (AHLs), known as autoinducer 1 (AI-1). Studies reveal the inhibition of quorum sensing in these bacteria by enzymes that degrade AHLS, in a process called quorum quenching. Typically Brazilian, Canastra cheese is a matured artisanal product, produced from raw milk and pingo, a type of endogenous culture collected and used daily in production. The microbial composition of pingo is diverse and characteristic of the producing region. This combination of bacteria, unique in each cheese factory, results in a typical aroma and texture. While the Gram-positive microbiota contributes to the development of flavor, texture and aroma in the product, Gram-negative bacteria in these cheeses are generally associated with the formation of eyes, off-flavors, poor curd coagulation and even pathogenicity. Thus, this work aimed to analyze the interaction between the Gram-positive and Gram-negative microbiota present in this culture by detecting quorum sensing and quorum quenching systems in the samples. The presence of AHLs was evaluated in 45 samples of pingo, with extraction with acidified ethyl acetate and the evaluation of the extracts through bioassays with Agrobacterium tumefaciens WCF47(pCF218)(pCF372) and KYC55(pJZ410)(pJZ372)(pJZ384 ), resulting in only one positive sample. Then, 350 isolates were obtained from 11 endogenous culture samples, with 200 being classified as Gram-positive and 150 Gram-negative. Gram-negatives were evaluated for the production of AHLs in vitro by plaque assay using the biosensor strains A. tumefaciens WCF47(pCF218)(pCF372), Chromobacterium violaceum CV026 and Escherichia coli pSB403, resulting in 39 AHL-producing isolates from 10 different samples. Gram-positive isolates were analyzed for their ability to inhibit quorum sensing using biosensor strains C. violaceum CV026 and A. tumefaciens WCF47(pCF218)(pCF372), in medium supplemented with N-hexanoyl-L-homoserine lactone or 3-oxo-dodecanoyl-Lhomoserine lactone. Total inhibition of the quorum response was detected by 78 tested isolates, while partial inhibition was caused by 63. Growth inhibition of biosensor strains was also observed for 24 isolates. Partial inhibition promoter isolates were recultured on minimal medium with C6-HSL or 3-oxo-C12-HSL as sole carbon sources. Twenty-eight isolates were recovered, and the action of these isolates on different substrates was evaluated, resulting in 22 lactonase producers and 6 acylase producers. The 39 Gram-negative isolates and the final 28 Grampositive isolates were identified by MALDI-TOF MS, resulting, to the best of the author's knowledge, in the first report of AHL production by Pseudomonas fulva, Enterobacter xiangfangensis and Lelliottia amnigena, as well as the lactonase production by Staphylococcus xylosus and acylase production by S. aureus, Microbacterium maritypicum and Rothia kristinae. This work demonstrated that population interactions mediated by AHLs-dependent quorum sensing in Canastra cheese endogenous culture microbiota are possible. However, these interactions are prone to inhibition by lactonases and acylases produced by Gram-positive bacteria


Subject(s)
Cheese/analysis , Milk/adverse effects , Quorum Sensing , Microbiota , Agrobacterium tumefaciens/classification , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization , Microbacterium , Gram-Negative Bacteria/metabolism , Gram-Positive Bacteria/metabolism
SELECTION OF CITATIONS
SEARCH DETAIL