RESUMEN
Bloodstream infections (BSIs) are serious infections associated with high rates of morbidity and mortality. Every hour delay in initiation of an effective antibiotic increases mortality due to sepsis by 7%. Turnaround time (TAT) for conventional blood cultures takes 48h, forcing physicians to streamline therapy by exposing patients to broad-spectrum antimicrobials. Our objective was (1) to evaluate the accuracy and TAT of an optimized workflow combining direct matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) and in-house real-time polymerase chain reaction (PCR) for bacterial identification and antimicrobial resistance profiling directly from positive blood bottles for diagnosing bloodstream infections and (2) to verify the effect of reporting results to medical staff. A total of 103 BSI episodes from 91 patients admitted to three hospitals in São Paulo, Brazil were included. TAT from molecular versus conventional methods was measured and compared. Our protocol showed an overall agreement of 93.5% for genus and 78.5% for species identification; 74.2% for methicillin resistance detection, 89.2% for extended-spectrum ß-lactamase profiling, 77.8% for metallo-ß-lactamase profiling, and 100% for carbapenemase profile and vancomycin-resistance detection when compared with conventional testing. TAT of molecular sample processing according to our protocol was 38h shorter than conventional methods. Antimicrobial interventions were possible in 27 BSI episodes. Antimicrobial discontinuation was achieved in 12 BSI episodes while escalation of therapy occurred in 15 episodes. Antimicrobial therapy was inadequate in three (12%) BSI episodes diagnosed using results of molecular testing. Our in-house rapid protocol for identifying both bacteria and antimicrobial resistance provided rapid and accurate results, having good agreement with conventional testing results. These results could contribute to faster antimicrobial therapy interventions in BSI episodes.
Asunto(s)
Bacteriemia/diagnóstico , Bacterias Gramnegativas/clasificación , Bacterias Grampositivas/clasificación , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Antibacterianos/administración & dosificación , Bacteriemia/tratamiento farmacológico , Bacteriemia/microbiología , Niño , Preescolar , Femenino , Bacterias Gramnegativas/genética , Bacterias Grampositivas/genética , Humanos , Lactante , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Reacción en Cadena en Tiempo Real de la Polimerasa , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Factores de Tiempo , Adulto JovenRESUMEN
A simple and reliable protocol using 0.1% trifluoroacetic acid (TFA) was developed to identify bacteria directly from blood cultures on the Vitek® MS system. Results presented a correlation of 99% for Gram-negative bacteria at species level, and 86.3% and 82.3% of Gram-positive bacteria at the genus and species levels, respectively.
Asunto(s)
Bacteriemia/diagnóstico , Técnicas Bacteriológicas/métodos , Sangre/microbiología , Bacterias Gramnegativas/aislamiento & purificación , Bacterias Grampositivas/aislamiento & purificación , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción/métodos , Ácido Trifluoroacético , Bacteriemia/microbiología , Bacterias Gramnegativas/química , Bacterias Gramnegativas/clasificación , Infecciones por Bacterias Gramnegativas/diagnóstico , Infecciones por Bacterias Gramnegativas/microbiología , Bacterias Grampositivas/química , Bacterias Grampositivas/clasificación , Infecciones por Bacterias Grampositivas/diagnóstico , Infecciones por Bacterias Grampositivas/microbiología , HumanosRESUMEN
ABSTRACT Bloodstream infections (BSIs) are serious infections associated with high rates of morbidity and mortality. Every hour delay in initiation of an effective antibiotic increases mortality due to sepsis by 7%. Turnaround time (TAT) for conventional blood cultures takes 48 h, forcing physicians to streamline therapy by exposing patients to broad-spectrum antimicrobials. Our objective was (1) to evaluate the accuracy and TAT of an optimized workflow combining direct matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) and in-house real-time polymerase chain reaction (PCR) for bacterial identification and antimicrobial resistance profiling directly from positive blood bottles for diagnosing bloodstream infections and (2) to verify the effect of reporting results to medical staff. A total of 103 BSI episodes from 91 patients admitted to three hospitals in São Paulo, Brazil were included. TAT from molecular versus conventional methods was measured and compared. Our protocol showed an overall agreement of 93.5% for genus and 78.5% for species identification; 74.2% for methicillin resistance detection, 89.2% for extended-spectrum β-lactamase profiling, 77.8% for metallo-β-lactamase profiling, and 100% for carbapenemase profile and vancomycin-resistance detection when compared with conventional testing. TAT of molecular sample processing according to our protocol was 38 h shorter than conventional methods. Antimicrobial interventions were possible in 27 BSI episodes. Antimicrobial discontinuation was achieved in 12 BSI episodes while escalation of therapy occurred in 15 episodes. Antimicrobial therapy was inadequate in three (12%) BSI episodes diagnosed using results of molecular testing. Our in-house rapid protocol for identifying both bacteria and antimicrobial resistance provided rapid and accurate results, having good agreement with conventional testing results. These results could contribute to faster antimicrobial therapy interventions in BSI episodes.
Asunto(s)
Humanos , Masculino , Femenino , Lactante , Preescolar , Niño , Adolescente , Adulto , Persona de Mediana Edad , Anciano , Anciano de 80 o más Años , Adulto Joven , Bacteriemia/diagnóstico , Bacterias Gramnegativas/clasificación , Bacterias Grampositivas/clasificación , Factores de Tiempo , Estudios Prospectivos , Bacteriemia/microbiología , Bacteriemia/tratamiento farmacológico , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Reacción en Cadena en Tiempo Real de la Polimerasa , Bacterias Gramnegativas/genética , Bacterias Grampositivas/genética , Antibacterianos/administración & dosificaciónRESUMEN
INTRODUCTION: Methicillin-resistant Staphylococcus aureus (MRSA) is an important pathogen commonly associated with nosocomial infections. However, it has also been associated with community-acquired skin and soft tissue infections (CA-MRSA). There are few data on the identification and prevalence of CA-MRSA infections in Brazil. METHODS: This is a cross-sectional study of 104 patients with community-acquired skin infections attending two health care centers in Porto Alegre, southern Brazil. MRSA isolates were characterized by molecular methods, including detection of the mecA gene by PCR, gene SCCmec typing, Panton-Valentine leukocidin (PVL) detection, pulsed-field gel electrophoresis (PFGE), and multilocus sequence typing (MLST). RESULTS: From the 104 samples, 58 Staphylococcus aureus isolates were obtained, of which five (8.6%) had a CA-MRSA-resistant profile. All five isolates had the mecA gene and amplified to SCCmec type IV. Analysis of chromosomal DNA by PFGE revealed the presence of two clusters related to international clones (OSPC and USA 300), with a Dice similarity coefficient >80%. The study was complemented by MLST, which detected three different strains: ST30, ST8, and ST45, the latter not presenting any relation with the clones compared in PFGE. CONCLUSIONS: The presence of CA-MRSA reveals an important change in the epidemiology of this pathogen and adds new elements to the knowledge of the molecular biology of infections by MRSA with SCCmec type IV in southern Brazil.
Asunto(s)
Staphylococcus aureus Resistente a Meticilina , Infecciones de los Tejidos Blandos/microbiología , Infecciones Estafilocócicas/microbiología , Adolescente , Adulto , Antibacterianos/farmacología , Toxinas Bacterianas , Técnicas de Tipificación Bacteriana , Brasil/epidemiología , Niño , Infecciones Comunitarias Adquiridas/epidemiología , Infecciones Comunitarias Adquiridas/microbiología , Estudios Transversales , ADN Bacteriano , Electroforesis en Gel de Campo Pulsado , Exotoxinas , Femenino , Humanos , Leucocidinas , Masculino , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Staphylococcus aureus Resistente a Meticilina/genética , Staphylococcus aureus Resistente a Meticilina/aislamiento & purificación , Pruebas de Sensibilidad Microbiana , Tipificación de Secuencias Multilocus , Infecciones de los Tejidos Blandos/epidemiología , Infecciones Estafilocócicas/epidemiología , Adulto JovenRESUMEN
The aim of this study was to describe a case of necrotizing pneumonia caused by methicillin-resistant Staphylococcus aureus. The sample was isolated from a blood culture collected less than 48 hours after hospital admission. The patient had been healthy until the infectious process started. The isolate had the mecA gene with "staphylococcal cassette chromosome mec" (SCCmec) type IVa. The possibility that Staphylococcus aureus harboring this genetic determinant might be present in our setting should be considered in situations of severe pneumonia within the community.
Asunto(s)
Staphylococcus aureus Resistente a Meticilina/aislamiento & purificación , Neumonía Estafilocócica/microbiología , Adolescente , Proteínas Bacterianas/genética , Infecciones Comunitarias Adquiridas/microbiología , Femenino , Humanos , Staphylococcus aureus Resistente a Meticilina/genética , Necrosis , Proteínas de Unión a las Penicilinas , Neumonía Estafilocócica/patologíaRESUMEN
Methicillin-resistant Staphylococcus aureus was initially described as a typical microorganism acquired in nosocomial infections. However, over recent years, community-acquired methicillin-resistant Staphylococcus aureus has been a cause of skin and soft-tissue infections. Serious infections such as pneumonia and sepsis can also occur. This report describes a case of sepsis in a child that was complicated by pneumonia secondary to soft tissue lesions that were due to community-acquired methicillin-resistant Staphylococcus aureus in southern Brazil. The patient was attended at the Emergency Unit with a history of injury caused by lower-limb trauma that evolved to cellulitis, pneumonia and sepsis.
Asunto(s)
Staphylococcus aureus Resistente a Meticilina/aislamiento & purificación , Neumonía Estafilocócica/microbiología , Sepsis/microbiología , Infecciones Cutáneas Estafilocócicas/microbiología , Antibacterianos/uso terapéutico , Niño , Clindamicina/uso terapéutico , Infecciones Comunitarias Adquiridas/diagnóstico , Infecciones Comunitarias Adquiridas/tratamiento farmacológico , Infecciones Comunitarias Adquiridas/microbiología , Gentamicinas/uso terapéutico , Humanos , Masculino , Neumonía Estafilocócica/complicaciones , Neumonía Estafilocócica/tratamiento farmacológico , Sepsis/complicaciones , Sepsis/tratamiento farmacológico , Infecciones Cutáneas Estafilocócicas/complicaciones , Infecciones Cutáneas Estafilocócicas/tratamiento farmacológico , Resultado del TratamientoRESUMEN
INTRODUCTION: Methicillin-resistant Staphylococcus aureus (MRSA) is an important pathogen commonly associated with nosocomial infections. However, it has also been associated with community-acquired skin and soft tissue infections (CA-MRSA). There are few data on the identification and prevalence of CA-MRSA infections in Brazil. METHODS: This is a cross-sectional study of 104 patients with community-acquired skin infections attending two health care centers in Porto Alegre, southern Brazil. MRSA isolates were characterized by molecular methods, including detection of the mecA gene by PCR, gene SCCmec typing, Panton-Valentine leukocidin (PVL) detection, pulsed-field gel electrophoresis (PFGE), and multilocus sequence typing (MLST). RESULTS: From the 104 samples, 58 Staphylococcus aureus isolates were obtained, of which five (8.6%) had a CA-MRSA-resistant profile. All five isolates had the mecA gene and amplified to SCCmec type IV. Analysis of chromosomal DNA by PFGE revealed the presence of two clusters related to international clones (OSPC and USA 300), with a Dice similarity coefficient >80%. The study was complemented by MLST, which detected three different strains: ST30, ST8, and ST45, the latter not presenting any relation with the clones compared in PFGE. CONCLUSIONS: The presence of CA-MRSA reveals an important change in the epidemiology of this pathogen and adds new elements to the knowledge of the molecular biology of infections by MRSA with SCCmec type IV in southern Brazil.
Asunto(s)
Adolescente , Adulto , Niño , Femenino , Humanos , Masculino , Adulto Joven , Staphylococcus aureus Resistente a Meticilina , Infecciones de los Tejidos Blandos/microbiología , Infecciones Estafilocócicas/microbiología , Antibacterianos/farmacología , Toxinas Bacterianas , Técnicas de Tipificación Bacteriana , Brasil/epidemiología , Estudios Transversales , Infecciones Comunitarias Adquiridas/epidemiología , Infecciones Comunitarias Adquiridas/microbiología , ADN Bacteriano , Electroforesis en Gel de Campo Pulsado , Exotoxinas , Leucocidinas , Pruebas de Sensibilidad Microbiana , Tipificación de Secuencias Multilocus , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Staphylococcus aureus Resistente a Meticilina/genética , Staphylococcus aureus Resistente a Meticilina/aislamiento & purificación , Infecciones de los Tejidos Blandos/epidemiología , Infecciones Estafilocócicas/epidemiologíaRESUMEN
O objetivo desse estudo foi descrever um caso de pneumonia necrotizante por Staphylococcus aureus resistente a meticilina. A amostra foi isolada em hemocultura coletada menos de 48 horas da admissão hospitalar. A paciente era previamente hígida quando do início do processo infeccioso. O isolado possuía o gene mecA, com "staphylococcal cassette chromosome mec" tipo IVa". A presença de Staphylococcus aureus carreando esse determinante genético em nosso meio deve ser considerada em pneumonias comunitárias graves.
The aim of this study was to describe a case of necrotizing pneumonia caused by methicillin-resistant Staphylococcus aureus. The sample was isolated from a blood culture collected less than 48 hours after hospital admission. The patient had been healthy until the infectious process started. The isolate had the mecA gene with "staphylococcal cassette chromosome mec" (SCCmec) type IVa. The possibility that Staphylococcus aureus harboring this genetic determinant might be present in our setting should be considered in situations of severe pneumonia within the community.
Asunto(s)
Adolescente , Femenino , Humanos , Staphylococcus aureus Resistente a Meticilina/aislamiento & purificación , Neumonía Estafilocócica/microbiología , Proteínas Bacterianas/genética , Infecciones Comunitarias Adquiridas/microbiología , Staphylococcus aureus Resistente a Meticilina/genética , Necrosis , Neumonía Estafilocócica/patologíaRESUMEN
Staphylococcus aureus resistente à meticilina foi inicialmente descrito como um típico microrganismo adquirido em infecções nosocomiais. No entanto, nos últimos anos Staphylococcus aureus resistente à meticilina adquirido na comunidade é causa de infecções de pele e tecidos moles, mas infecções graves como pneumonia e sepse podem ocorrer. Este relato descreve um caso de sepse em criança, complicado com pneumonia secundária a lesão em partes moles por Staphylococcus aureus resistente à meticilina adquirido na comunidade no Sul do Brasil. O paciente foi atendido em Unidade de Emergência com história de ferimento provocado por trauma em membro inferior que evoluiu para celulite, pneumonia e sepse.
Methicillin-resistant Staphylococcus aureus was initially described as a typical microorganism acquired in nosocomial infections. However, over recent years, community-acquired methicillin-resistant Staphylococcus aureus has been a cause of skin and soft-tissue infections. Serious infections such as pneumonia and sepsis can also occur. This report describes a case of sepsis in a child that was complicated by pneumonia secondary to soft tissue lesions that were due to community-acquired methicillin-resistant Staphylococcus aureus in southern Brazil. The patient was attended at the Emergency Unit with a history of injury caused by lower-limb trauma that evolved to cellulitis, pneumonia and sepsis.