Bacteria, yeasts, and fungi associated with larval food of Brazilian native stingless bees.

Stingless bees are a diverse group with a relevant role in pollinating native species. Its diet is rich in carbohydrates and proteins, by collecting pollen and nectar supplies the development of its offspring. Fermentation of these products is associated with microorganisms in the colony. However, the composition of microorganisms that comprise this microbiome and its fundamental role in colony development is still unclear. To characterize the colonizing microorganisms of larval food in the brood cells of stingless bees Frieseomelitta varia, Melipona quadrifasciata, Melipona scutellaris, and Tetragonisca angustula, we have utilized molecular and culture-based techniques. Bacteria of the phyla Firmicutes, Proteobacteria, Actinobacteria, and fungi of the phyla Ascomycota, Basidiomycota, Mucoromycota, and Mortierellomycota were found. Diversity analysis showed that F. varia had a greater diversity of bacteria in its microbiota, and T. angustula had a greater diversity of fungi. The isolation technique allowed the identification of 189 bacteria and 75 fungi. In summary, this research showed bacteria and fungi associated with the species F. varia, M. quadrifasciata, M. scutellaris, and T. angustula, which may play an essential role in the survival of these organisms. Besides that, a biobank with bacteria and fungus isolates from LF of Brazilian stingless bees was created, which can be used for different studies and the prospection of biotechnology compounds.

Inappropriate empirical antimicrobial treatment in bloodstream infections patients in the era of multidrug resistance / Terapia Empírica Inapropriada no Tratamento de Infecções de Corrente Sanguínea na Era da Multirresistência Antimicrobiana / Tratamiento antimicrobiano empírico inadecuado en pacientes con infecciones del torrente sanguíneo

Background and objectives: Bloodstream infection (BSI) by multidrug-resistant Pseudomonas aeruginosa is a severe infection. This study aimed to evaluate and identify the predictors of mortality in patients who had bloodstream infection by carbapenem-resistant P. aeruginosa. Methods: This is a retrospective cohort study, approved by Committee of Ethics in Research with Human Participants, which included 87 consecutive patients hospitalized in a referral hospital in Brazil. Clinical and demographic information about each patient were obtained from hospital records. The Student's T-test was used to compare continuous variables and x2 or Fisher's exact tests to compare categorical variables. To determine independent risk factors for 30-day mortality, a multiple logistic regression model was used. A survival curve was constructed using the Kaplan­Meier method. Results: Among the patients, 87.3% use antibiotics previously, 60.9% received inadequate empirical treatment, and the 30-day mortality rate was 57.5%. Inappropriate antibiotic empirical therapy was independently associated with a 30-days death and mortality rate. Conclusion: These findings can show some insights about the relationship between higher mortality and inappropriate empirical therapy for patients with BSI by P. aeruginosa. There is a need for better diagnostic tests and infection control programs should focus on de-escalation the antibiotic inappropriate therapy, mainly in BSI caused by carbapenem-resistant P. aeruginosa.(AU)

Justificativa e objetivos: Infecção da corrente sanguínea (ICS) por Pseudomonas aeruginosa multirresistente é grave. Este estudo teve como objetivo avaliar e identificar os preditores de mortalidade em pacientes admitidos em uma Unidade de Terapia Intensiva que apresentaram infecção da corrente sanguínea por P. aeruginosa resistente aos carbapenêmicos. Métodos: Trata-se de um estudo de coorte retrospectivo, aprovado pelo Comitê de Ética em Pesquisa com Seres Humanos, que incluiu 87 pacientes consecutivos internados em um hospital de referência no Brasil. As informações clínicas e demográficas de cada paciente foram obtidas através de análise dos prontuários dos pacientes. O teste T de Student foi usado para comparar variáveis contínuas e o teste x2 ou exato de Fisher para comparar variáveis categóricas. Para determinar fatores de risco independentes para mortalidade em 30 dias, foi utilizado um modelo de regressão logística múltipla. Uma curva de sobrevida foi construída pelo método de Kaplan-Meier. Resultados: Do total de pacientes, 87,3% faziam uso prévio de antibióticos, 60,9% receberam tratamento empírico inadequado e a mortalidade em 30 dias foi de 57,5%. A terapia empírica inadequada foi fator de risco independente para mortalidade. Conclusão: Esses achados revelam alguns insights sobre a relação entre maior mortalidade e terapia empírica inadequada para pacientes com ICS por P. aeruginosa. Além disso, destacam a necessidade de melhores testes diagnósticos e os programas de controle de infecção devem se concentrar na redução da terapia inadequada com antibióticos, principalmente na ICS causada por P. aeruginosa resistente a carbapenêmicos.(AU)

Justificación y objetivos: La infección del torrente sanguíneo por Pseudomonas aeruginosa multirresistente es grave. Este estudio tuvo como objetivo evaluar e identificar predictores de mortalidad en pacientes ingresados en una Unidad de Cuidados Intensivos que presentaban infección del torrente sanguíneo por P. aeruginosa resistente a carbapenémicos. Métodos: Se trata de un estudio de cohorte retrospectivo, aprobado por el Comité de Ética en Investigación con Participantes Humanos, que incluyó 87 pacientes consecutivos ingresados en un hospital de referencia en Brasil. La información clínica y demográfica de cada paciente se obtuvo mediante el análisis de las historias clínicas de los pacientes. Se utilizó la prueba t de Student para comparar variables continuas y x2 o prueba exacta de Fisher para comparar variables categóricas. Para determinar los factores de riesgo independientes para la mortalidad a los 30 días, se utilizó un modelo de regresión logística múltiple. Se construyó una curva de supervivencia utilizando el método de Kaplan-Meier. Resultados: Del total de pacientes, el 87,3% utilizaba antibióticos previamente, el 60,9% recibió tratamiento empírico inadecuado y la tasa de mortalidad a los 30 días fue del 57,5%. La terapia empírica inadecuada fue un factor de riesgo independiente de mortalidad. Conclusión: Estos hallazgos revelan algunos conocimientos sobre la relación entre el aumento de la mortalidad y la terapia empírica inadecuada para los pacientes con infección del torrente sanguíneo por P. aeruginosa. Además, destacan la necesidad de mejores pruebas de diagnóstico y los programas de control de infecciones deben centrarse en reducir la terapia con antibióticos inapropiados, particularmente en infección del torrente sanguíneo causados por P. aeruginosa resistente a carbapenémicos.(AU)

Antimicrobial activity of supernatants produced by bacteria isolated from Brazilian stingless bee's larval food.

BACKGROUND: The discovery of new molecules with antimicrobial properties has been a promising approach, mainly when related to substances produced by bacteria. The use of substances produced by bees has evidenced the antimicrobial action in different types of organisms. Thus, the use of bacteria isolated from larval food of stingless bees opens the way for the identification of the new molecules. The effect of supernatants produced by these bacteria was evaluated for their ability to inhibit the growth of bacteria of clinical interest. Furthermore, their effects were evaluated when used in synergy with antibiotics available in the pharmaceutical industry. RESULTS: A few supernatants showed an inhibitory effect against susceptible and multiresistant strains in the PIC assay and the modulation assay. Emphasizing the inhibitory effect on multidrug-resistant strains, 7 showed an effect on multidrug-resistant Escherichia coli (APEC), Klebsiella pneumoniae carbapenemase (KPC), multidrug-resistant Pseudomonas aeruginosa, and multidrug-resistant Staphylococcus aureus (MRSA) in the PIC assay. Of the supernatants analyzed, some presented synergism for more than one species of multidrug-resistant bacteria. Nine had a synergistic effect with ampicillin on E. coli (APEC) or S. aureus (MRSA), 5 with penicillin G on E. coli (APEC) or KPC, and 3 with vancomycin on KPC. CONCLUSION: In summary, the results indicate that supernatants produced from microorganisms can synthesize different classes of molecules with potent antibiotic activity against multiresistant bacteria. Thus, suggesting the use of these microorganisms for use clinical tests to isolate the molecules produced and their potential for use.

Carbapenem-resistant Pseudomonas aeruginosa: association with virulence genes and biofilm formation

Abstract Pseudomonas aeruginosa is an opportunistic pathogen that causes frequently nosocomial infections, currently becoming more difficult to treat due to the various resistance mechanisms and different virulence factors. The purpose of this study was to determine the risk factors independently associated with the development of bacteremia by carbapenem-resistant P. aeruginosa, the frequency of virulence genes in metallo-β-lactamases producers and to evaluate their ability to produce biofilm. We conducted a case–control study in the Uberlândia Federal University – Hospital Clinic, Brazil. Polymerase Chain Reaction was performed for metallo-β-lactamases and virulence genes. Adhesion and biofilm assays were done by quantitative tests. Among the 157 strains analyzed, 73.9% were multidrug-resistant, 43.9% were resistant to carbapenems, 16.1% were phenotypically positive for metallo-β-lactamases, and of these, 10.7% were positive for blaSPM gene and 5.3% positive for blaVIM. The multivariable analysis showed that mechanical ventilation, enteral/nasogastric tubes, primary bacteremia with unknown focus, and inappropriate therapy were independent risk factors associated with bacteremia. All tested strains were characterized as strongly biofilm producers. A higher mortality was found among patients with bacteremia by carbapenem-resistant P. aeruginosa strains, associated independently with extrinsic risk factors, however it was not evident the association with the presence of virulence and metallo-β-lactamases genes.

Molecular epidemiological survey of bacteremia by multidrug resistant Pseudomonas aeruginosa: the relevance of intrinsic resistance mechanisms.

The bacterial factors associated with bacteremia by multidrug-resistant and extensively drug-resistant P. aeruginosa, including overexpression of efflux pumps, AmpC overproduction, and loss/alteration of the OprD porin in isolates that are non-Metallo-ß-Lactamase producing were analyzed in a retrospective study. Molecular analyses included strain typing by Pulsed Field Gel Electrophoresis and identification of key genes via qualitative and quantitative PCR-based assays. Previous use of carbapenems and tracheostomy was independently associated with the development of bacteremia by extensively drug-resistant and multidrug-resistant strains of P. aeruginosa. A high consumption of antimicrobials was observed, and 75.0% of the isolates contained amplicons with the blaSPM-1 and blaVIM genes. Of the 47 non-Metallo-ß-Lactamase isolates, none had another type of carbapenemase. However, the isolates exhibited high rates of hyperproduction of AmpC, loss of the OprD porin (71.4%) and the presence of MexABOprM (57.1%) and MexXY (64.3%). This study suggests that in non-Metallo-ß-Lactamase isolates, the association of intrinsic resistance mechanisms could contributes to the expression of multidrug-resistant/extensively drug-resistant phenotypes.

Carbapenem-resistant Pseudomonas aeruginosa: association with virulence genes and biofilm formation.

Pseudomonas aeruginosa is an opportunistic pathogen that causes frequently nosocomial infections, currently becoming more difficult to treat due to the various resistance mechanisms and different virulence factors. The purpose of this study was to determine the risk factors independently associated with the development of bacteremia by carbapenem-resistant P. aeruginosa, the frequency of virulence genes in metallo-ß-lactamases producers and to evaluate their ability to produce biofilm. We conducted a case-control study in the Uberlândia Federal University - Hospital Clinic, Brazil. Polymerase Chain Reaction was performed for metallo-ß-lactamases and virulence genes. Adhesion and biofilm assays were done by quantitative tests. Among the 157 strains analyzed, 73.9% were multidrug-resistant, 43.9% were resistant to carbapenems, 16.1% were phenotypically positive for metallo-ß-lactamases, and of these, 10.7% were positive for blaSPM gene and 5.3% positive for blaVIM. The multivariable analysis showed that mechanical ventilation, enteral/nasogastric tubes, primary bacteremia with unknown focus, and inappropriate therapy were independent risk factors associated with bacteremia. All tested strains were characterized as strongly biofilm producers. A higher mortality was found among patients with bacteremia by carbapenem-resistant P. aeruginosa strains, associated independently with extrinsic risk factors, however it was not evident the association with the presence of virulence and metallo-ß-lactamases genes.

Clinical and Molecular Epidemiology of Multidrug-Resistant P. aeruginosa Carrying aac(6')-Ib-cr, qnrS1 and blaSPM Genes in Brazil.

We described a comprehensive analysis of the molecular epidemiology of multidrug-resistant (MDR) P. aeruginosa. Molecular analysis included typing by Pulsed Field Gel Electrophoresis, identification of genes of interest through PCR-based assays and sequencing of target genes. Case-control study was conducted to better understand the prognostic of patients and the impact of inappropriate therapy in patients with bacteremia, as well as the risk factors of MDR infections. We observed a high rate of MDR isolates (40.7%), and 51.0% of them was independently associated with inappropriate antibiotic therapy. Bacteremia was detected in 66.9% of patients, and prolonged hospital stay was expressive in those resistant to fluoroquinolone. Plasmid-mediated quinolone resistance genes (PMQR), qnrS1 and aac(6')Ib-cr, were detected in two different nosocomial isolates (5.3%), and the aac(6')-Ib7 variant was detected at a high frequency (87.5%) in those negative to PMQR. The presence of mutations in gyrA and parC genes was observed in 100% and 85% of selected isolates, respectively. Isolates harboring PMQR genes or mutations in gyrA and parC were not closely related, except in those containing SPM (São Paulo metallo-ß-lactamase) clone. In addition, there is no study published in Brazil to date reporting the presence of Pseudomonas aeruginosa isolates harboring both qnrS1 and aac(6')Ib-cr genes, with alarming frequency of patients with inappropriate therapy.