Pneumonia associada à ventilação mecânica: incidência, etiologia microbiana e perfil de resistência aos antimicrobianos

Background and Objectives: Infections caused by multi-drug resistant microorganisms have a great clinical and economic impact. The present study proposed to determine and assess ventilator-associated pneumonia (VAP) incidence in an Intensive Care Unit (ICU), to establish the profile of hospitalized patients and to determine the frequency of microorganisms isolated as well as their antimicrobial resistance profile. Methods:  A descriptive, documental study, with a quantitative approach, carried out at a teaching hospital. Participants were all individuals admitted to the General ICU who developed VAP in 2018 and 2019. Results: During the study, 146 patients were diagnosed with VAP, with an incidence of 23.66/1000 patient-days on mechanical ventilation. The median age of patients was 52.5 years and most of them were man. One hundred and eight microorganisms were isolated in cultures, the majority being gram-negative bacteria. Non-fermenting bacteria were the most frequent (n=46; 42.6%), followed by enterobacteria (n=42; 38.9%). Staphylococcus aureus was the most frequent microorganism among gram-positive (n=17; 15.7%). The most frequent multi-drug resistant bacteria were Acinetobacter baumannii and Enterobacter spp. No microorganism showed colistin and vancomycin resistance. Patients infected with multidrug-resistant bacteria were hospitalized longer when compared to other patients. Conclusions: VAP incidence was high. The knowledge of the etiologic agents of VAP and their antimicrobial resistance profile is fundamental to support the elaboration of institutional treatment protocols as well as assist in empirical antibiotic therapy.Justificación y Objetivos: Las infecciones causadas por microorganismos multirresistentes tienen un gran impacto clínico y económico. El presente estudio propuso determinar y evaluar la incidencia de neumonía asociada a la ventilación mecánica (NAV); establecer el perfil de los pacientes hospitalizados; y determinar la frecuencia de microorganismos aislados y su perfil de resistencia a los antimicrobianos. Métodos: Estudio descriptivo, documental, de enfoque cuantitativo, realizado en un hospital universitario con todos los pacientes que ingresaron en la Unidad de Cuidados Intensivos (UCI) General y desarrollaron NAV en 2018 y 2019. Resultados: Durante el período de estudio, 146 pacientes fueron diagnosticados de NAV, con una incidencia de 23,66/1000 pacientes-día en ventilación mecánica. La mediana de edad de los pacientes fue de 52,5 años, con predominio del sexo masculino. Un total de 108 microorganismos fueron aislados en cultivo, representados en su mayoría por bacterias gram negativas. Las bacterias no fermentadoras fueron las más frecuentes (n=46; 42,6%), seguido de las enterobacterias (n=42; 38,9%). Entre las gram positivas, Staphylococcus aureus fue la más frecuente (n=17; 15,7%). Las bacterias multirresistentes más frecuentes fueron Acinetobacter baumannii y Enterobacter spp. Ningún microorganismo mostró resistencia a la colistina y la vancomicina. Los pacientes infectados con bacterias multirresistentes estuvieron hospitalizados durante más tiempo en comparación con otros pacientes. Conclusión: La incidencia de NAV fue alta. El conocimiento de los agentes etiológicos de la NAV y su perfil de resistencia a los antimicrobianos es fundamental para elaborar protocolos de tratamiento institucional, así como ayudar en la antibioticoterapia empírica.Justificativa e Objetivos: Infecções causadas por microrganismos multirresistentes acarretam um grande impacto clínico e econômico. O presente estudo propôs determinar e avaliar a incidência de pneumonia associada à ventilação mecânica (PAV), estabelecer o perfil dos pacientes internados e determinar a frequência dos microrganismos isolados, bem como seu perfil de resistência aos antimicrobianos. Métodos: Estudo descritivo, documental, com abordagem quantitativa, realizado em um hospital escola com todos os indivíduos internados na Unidade de Terapia Intensiva (UTI) Geral que desenvolveram PAV nos anos de 2018 e 2019. Resultados: No estudo, 146 pacientes tiveram o diagnóstico de PAV, com uma incidência de 23,66/1000 pacientes-dia em ventilação mecânica. A mediana de idade dos pacientes foi 52,5 anos, com predominância do sexo masculino. Um total de 108 microrganismos foram isolados em culturas, sendo a maioria bactérias Gram-negativas. As bactérias não fermentadoras foram as mais frequentes (n=46; 42,6%), seguidas pelas enterobactérias (n=42; 38,9%). Entre as Gram-positivas, Staphylococcus aureus foi a mais frequente (n=17; 15,7%). As bactérias multirresistentes mais frequentes foram Acinetobacter baumannii e Enterobacter spp. Nenhum microrganismo apresentou resistência à colistina e à vancomicina. Os pacientes infectados com bactérias multirresistentes ficaram mais tempo hospitalizados, quando comparados aos demais pacientes. Conclusão: A incidência de PAV foi elevada. O conhecimento dos agentes etiológicos das PAV e seu perfil de resistência aos antimicrobianos é fundamental para embasar a elaboração dos protocolos institucionais de tratamento, bem como auxiliar na antibioticoterapia empírica

The polymyxin B-induced transcriptomic response of a clinical, multidrug-resistant Klebsiella pneumoniae involves multiple regulatory elements and intracellular targets

Background: The emergence of multidrug-resistant Klebsiella pneumoniae is a major public health concern. Many K. pneumoniae infections can only be treated when resorting to last-line drugs such as polymyxin B (PB). However, resistance to this antibiotic is also observed, although insufficient information is described on its mode of action as well as the mechanisms used by resistant bacteria to evade its effects. We aimed to study PB resistance and the influence of abiotic stresses in a clinical K. pneumoniae strain using whole transcriptome profiling. Results: We sequenced 12 cDNA libraries of K. pneumoniae Kp13 bacteria, from two biological replicates of the original strain Kp13 (Kp13) and five derivative strains: induced high-level PB resistance in acidic pH (Kp13pH), magnesium deprivation (Kp13Mg), high concentrations of calcium (Kp13Ca) and iron (Kp13Fe), and a control condition with PB (Kp13PolB). Our results show the involvement of multiple regulatory loci that differentially respond to each condition as well as a shared gene expression response elicited by PB treatment, and indicate the participation of two-regulatory components such as ArcA-ArcB, which could be involved in re-routing the K. pneumoniae metabolism following PB treatment. Modules of co-expressed genes could be determined, which correlated to growth in acid stress and PB exposure. We hypothesize that polymyxin B induces metabolic shifts in K. pneumoniae that could relate to surviving against the action of this antibiotic. Conclusions: We obtained whole transcriptome data for K. pneumoniae under different environmental conditions and PB treatment. Our results supports the notion that the K. pneumoniae response to PB exposure goes beyond damaged membrane reconstruction and involves recruitment of multiple gene modules and intracellular targets.Fil: Pereira Ramos, Pablo Ivan. Fundación Oswaldo Cruz; BrasilFil: Flores Custodio, Gregori Marlon. No especifíca;Fil: Quispe Saji, Guadalupe del Rosario. No especifíca;Fil: Cardoso, Thiago. No especifíca;Fil: Luchetti da Silva, Gisele. No especifíca;Fil: Braun, Graziela. Universidade Federal de Sao Paulo; BrasilFil: Martins, Williams. Universidade Federal de Sao Paulo; BrasilFil: Girardello, Raquel. Universidade Federal de Sao Paulo; BrasilFil: Ribeiro de Vasconcellos, Ana Teresa. No especifíca;Fil: Fernandez, Elmer Andres. Universidad Católica de Córdoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Gales, Cristina. Universidade Federal de Sao Paulo; BrasilFil: Nicolas, Marisa. No especifíca

The polymyxin B-induced transcriptomic response of a clinical, multidrug-resistant Klebsiella pneumoniae involves multiple regulatory elements and intracellular targets

Background: The emergence of multidrug-resistant Klebsiella pneumoniae is a major public health concern. Many K. pneumoniae infections can only be treated when resorting to last-line drugs such as polymyxin B (PB). However, resistance to this antibiotic is also observed, although insufficient information is described on its mode of action as well as the mechanisms used by resistant bacteria to evade its effects. We aimed to study PB resistance and the influence of abiotic stresses in a clinical K. pneumoniae strain using whole transcriptome profiling. Results: We sequenced 12 cDNA libraries of K. pneumoniae Kp13 bacteria, from two biological replicates of the original strain Kp13 (Kp13) and five derivative strains: induced high-level PB resistance in acidic pH (Kp13(pH)), magnesium deprivation (Kp13(Mg)), high concentrations of calcium (Kp13(Ca)) and iron (Kp13(Fe)), and a control condition with PB (Kp13(PolB)). Our results show the involvement of multiple regulatory loci that differentially respond to each condition as well as a shared gene expression response elicited by PB treatment, and indicate the participation of two-regulatory components such as ArcA-ArcB, which could be involved in re-routing the K. pneumoniae metabolism following PB treatment. Modules of co-expressed genes could be determined, which correlated to growth in acid stress and PB exposure. We hypothesize that polymyxin B induces metabolic shifts in K. pneumoniae that could relate to surviving against the action of this antibiotic. Conclusions: We obtained whole transcriptome data for K. pneumoniae under different environmental conditions and PB treatment. Our results supports the notion that the K. pneumoniae response to PB exposure goes beyond damaged membrane reconstruction and involves recruitment of multiple gene modules and intracellular targets.Fundacao de Amparo a Pesquisa do Estado do Rio de Janeiro (FAPERJ)Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES)Lab Nacl Comp Cient, Petropolis, RJ, BrazilFiocruz MS, Ctr Pesquisas Goncalo Moniz, Salvador, BA, BrazilUniv Fed Sao Paulo, Escola Paulista Med, Dept Internal Med, Lab Alerta,Div Infect Dis, Sao Paulo, SP, BrazilUniv Catolica Cordoba, Fac Ingn, CONICET, Cordoba, ArgentinaUniv Fed Sao Paulo, Escola Paulista Med, Dept Internal Med, Lab Alerta,Div Infect Dis, Sao Paulo, SP, BrazilFAPERJ: E-26/110.315/2014FAPESP: 2010/12891-9CAPES: 23038.010041/2013-13Web of Scienc

Genomics and epidemiology for gastric adenocarcinomas (GE4GAC): a Brazilian initiative to study gastric cancer

Abstract Gastric cancer (GC) is the fifth most common type of cancer worldwide with high incidences in Asia, Central, and South American countries. This patchy distribution means that GC studies are neglected by large research centers from developed countries. The need for further understanding of this complex disease, including the local importance of epidemiological factors and the rich ancestral admixture found in Brazil, stimulated the implementation of the GE4GAC project. GE4GAC aims to embrace epidemiological, clinical, molecular and microbiological data from Brazilian controls and patients with malignant and pre-malignant gastric disease. In this letter, we summarize the main goals of the project, including subject and sample accrual and current findings

Evaluation of adherence, hemagglutination, and presence of genes codifying for virulence factors of Acinetobacter baumannii causing urinary tract infection

Acinetobacter baumannii is a strictly aerobic bacterium which causes severe infections, however its pathogenic characteristics are not well defined. Thirteen A. baumannii strains isolated from urine of hospitalized and nonhospitalized patients with different ages were investigated for the presence of virulence factors. The isolates belonged to biotypes 2, 6, and 9 and were sensitive to imipenem. The majority of them showed resistance to amikacin, ceftazidime, ceftriaxone, ciprofloxacin, gentamicin, norfloxacin, and trimethoprim-sulfamethoxazole. None of A. baumannii strains presented genes codifying for 17 different virulence factors previously described in uropathogenic Escherichia coli, when tested by polymerase chain reaction (PCR). Nine isolates agglutinated human group AB erythrocytes, in presence of mannose, but none of them agglutinated group O erythrocytes. Adherence to polystyrene was observed in 7 isolates, and this result did not correlate with that obtained in hemagglutination assay. All the isolates were able to grow in iron-limiting conditions, showing that A. baumannii produces some type of siderophore. However, the genes iutA and fyuA, from iron uptake system of E. coli and Yersinia sp., respectively, were not present in the isolates, suggesting the presence of a different type of siderophore. The fimbriae of A. baumannii strains that mediates the adherence are possibly mannose-resistant, eventhough the mechanism of adherence to human epithelial cells still remains to be elucidated

Efeitos da terapia fotodinâmica e de uma única aplicação de laser de baixa potência em bactérias in vitro

Low-level laser therapy has been used to speed up healing process of pressure ulcers due to its antiinflammatory, analgesic, anti-edematous, and scarring effects. However there is no consensus on its effect on infected ulcers. The aim of this study was to verify the bactericidal effect of low-level laser therapy (InGaP, 670 nm) and photodynamic therapy (PDT) at 2, 4 and 6 J/cm² doses, onto gram-negative and gram-positive bacteria in vitro. Thirty two Petri plates were prepared, 16 with Pseudomonas aeruginosa and 16 with Staphilococcus aureus, and divided into eight subgroups each: three subgroups treated with 2 J/cm², 4 J/cm², and 6 J/cm² laser; three subgroups treated with 2 J/cm², 4 J/cm², and 6 J/cm² PDT; one treated solely with photosensitiser; and a non-treated (control) subgroup. Laser and PDT groups were irradiated once and incubated for 24 hours; the other two subgroups underwent no irradiation. Cultures were visually analysed in search of inhibition haloes. In all subgroups, for both bacteria, no inhibition or growing signs could be detected. Hence neither low-level laser or PDT (InGaP, 670 nm) produced any bactericidal or bacteriostatic effect, nor any biostimulation effect, onto analysed bacteria.O laser de baixa potência vem sendo usado para acelerar a cicatrização em úlceras de pressão devido a seus efeitos cicatrizante, antiinflamatório, antiedematoso e analgésico. No entanto, não há consenso quanto a seu efeito em úlceras infectadas. O objetivo deste estudo foi verificar o efeito bactericida da laserterapia e da terapia fotodinâmica (TFD) com laser de baixa potência, InGaP, 670 nm, em doses de 2, 4 e 6 J/cm², em bactérias gram-positivas e gram-negativas in vitro. Foram preparadas 32 placas de Petri com bactérias, 16 com Pseudomonas aeruginosa e 16 com Staphilococcus aureus. Aleatoriamente dividiu-se cada grupo em oito subgrupos (duas placas cada): três subgrupos tratados só com laserterapia, em doses de 2 J/cm², 4 J/cm² e 6 J/cm²; três subgrupos tratados com TFD, em doses de 2 J/cm², 4 J/cm² e 6 J/cm²; um tratado apenas com fotossensibilizante (azul de metileno a 0,1 µg/ml); e um subgrupo não tratado (controle). Os subgrupos laser e TFD foram irradiados uma única vez e incubados por 24 horas. Os outros dois subgrupos não receberam irradiação. As culturas foram analisadas visualmente para verificação ou não do halo de inibição. Em todos os subgrupos, de ambas as bactérias, não foi observado qualquer halo de inibição nem de crescimento. Conclui-se que a terapia a laser e a fotodinâmica de baixa potência (InGaP, 670 nm) não produziram efeitos bactericidas e/ou bacteriostáticos, tampouco tendo havido efeito bioestimulante sobre as bactérias