RESUMEN
BACKGROUND: Mixed microbial infections of the respiratory tracts with P. aeruginosa and A. fumigatus capable of producing biofilms are commonly found in cystic fibrosis patients. The primary objective of this study was to develop an in vitro model for P. aeruginosa and A. fumigatus polymicrobial biofilm to study the efficacy of various antimicrobial drugs alone and in combinations against biofilm-embedded cells. Simultaneous static cocultures of P. aeruginosa and sporelings were used for the development of in vitro P. aeruginosa-A. fumigatus polymicrobial biofilm in SD broth in 24-well cell culture plates at 35°C, and the biofilm formation was monitored microscopically and spectrophotometrically. Using P. aeruginosa-A. fumigatus sporelings cocultures we examined the effects of various antimicrobial drugs alone and in combination against polymicrobial biofilm by CFU and tetrazolium reduction assays. RESULTS: In simultaneous static cocultures P. aeruginosa cells killed A. fumigatus conidia, whereas the bacterial cells showed no substantial fungicidal effect on sporelings grown for 12 h or longer at 35°C. Monospecies cultures of P. aeruginosa produced loosely adhered monomicrobial biofilm and addition of 10% bovine serum to the growth medium inhibited the formation of monomicrobial biofilm by P. aeruginosa whereas it produced tightly adhered polymicrobial biofilm in the presence of A. fumigatus mycelial growth. A. fumigatus produced firmly adherent monomicrobial and polymicrobial biofilms. A comparison of CFU and MTT assays showed that the latter is unsuitable for studying the effectiveness of antimicrobial treatment against polymicrobial biofilm. Tobramycin alone and in combination with posaconazole was highly effective against monomicrobial and polymicrobial biofilms of P. aeruginosa whereas cefepime alone and in combination with posaconazole showed excellent activity against monomicrobial biofilm of P. aeruginosa but was less effective against polymicrobial biofilm. Monomicrobial and polymicrobial biofilms of A. fumigatus showed similar susceptibility to posaconazole with and without the antibacterial drug. CONCLUSIONS: Simultaneous static coculture of A. fumigatus sporelings grown for 12 h or longer was superior to ungerminated conidia with P. aeruginosa for the development of A. fumigatus-P. aeruginosa biofilm. P. aeruginosa-A. fumigatus polymicrobial biofilm shows differential susceptibility to antimicrobial drugs whereas the susceptibility of A. fumigatus to antimicrobial drugs was unchanged.
Asunto(s)
Antibacterianos/farmacología , Aspergillus fumigatus/efectos de los fármacos , Aspergillus fumigatus/fisiología , Biopelículas/efectos de los fármacos , Biopelículas/crecimiento & desarrollo , Pseudomonas aeruginosa/efectos de los fármacos , Pseudomonas aeruginosa/fisiología , Aspergillus fumigatus/crecimiento & desarrollo , Aspergillus fumigatus/metabolismo , Recuento de Colonia Microbiana , Pruebas de Sensibilidad Microbiana , Viabilidad Microbiana/efectos de los fármacos , Microscopía , Pseudomonas aeruginosa/crecimiento & desarrollo , Pseudomonas aeruginosa/metabolismo , Espectrofotometría , Coloración y Etiquetado , Sales de Tetrazolio/metabolismo , Tiazoles/metabolismoRESUMEN
To gain a better understanding of epidemiology of resistance in Staphylococcus aureus, we describe the molecular epidemiology of methicillin-resistant Staphylococcus aureus bloodstream isolates in urban Detroit. Bloodstream isolates from July 2005 to February 2007 were characterized. Two hundred ten bloodstream isolates from 201 patients were evaluated. Patient characteristics were as follows: median age, 54 years; 56% male; and 71% African-American. Seventy-six percent of infections were health care associated, with 55% being community-onset infections and 21% hospital acquired, and 24% were community associated. The most common sources were skin/wound (25%), central venous catheters (24%), unknown source (20%), and endocarditis (9%). Ninety percent and 5% of isolates had a MIC of vancomycin of
Asunto(s)
Bacteriemia/microbiología , Resistencia a la Meticilina , Epidemiología Molecular , Infecciones Estafilocócicas/microbiología , Staphylococcus aureus/clasificación , Staphylococcus aureus/efectos de los fármacos , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Antibacterianos/farmacología , Bacteriemia/epidemiología , Proteínas Bacterianas/genética , Técnicas de Tipificación Bacteriana , Análisis por Conglomerados , Infecciones Comunitarias Adquiridas/epidemiología , Infecciones Comunitarias Adquiridas/microbiología , Infección Hospitalaria/epidemiología , Infección Hospitalaria/microbiología , Dermatoglifia del ADN , ADN Bacteriano/genética , Electroforesis en Gel de Campo Pulsado , Femenino , Genotipo , Geografía , Humanos , Masculino , Michigan/epidemiología , Pruebas de Sensibilidad Microbiana , Persona de Mediana Edad , Infecciones Estafilocócicas/epidemiología , Staphylococcus aureus/genética , Staphylococcus aureus/aislamiento & purificación , Población Urbana , Resistencia a la Vancomicina , Factores de Virulencia/genéticaRESUMEN
Over an approximately 50-day period in 2015, an outbreak of CTX-M-15 extended spectrum ß-lactamase-(ESBL)-possessing Salmonella Isangi occurred among 19 adult surgical patients and one healthcare worker (HCW) at a large urban tertiary care hospital in the United States. A total of 45 S. Isangi isolates were isolated from stool (35), blood (4), urine (3), respiratory (2), and wound (1) cultures. Phenotypically, all but three isolates demonstrated resistance to ampicillin, ampicillin/sulbactam, ceftriaxone, and cefepime, and one isolate was resistant to ertapenem. Genotypically, a single CTX-M-15 ESBL was identified in all but three isolates by real-time PCR. Interestingly, two of the CTX-M-15 negative, susceptible isolates were isolated from a single patient who initially had a CTX-M positive, resistant strain. Isolates were clonally related, including both resistant and susceptible strains, as confirmed by pulse field gel electrophoresis (PFGE). This is the first case of a novel Salmonella outbreak at this hospital, and we believe it to be the first case of an S. Isangi serotype outbreak in the United States.
Asunto(s)
Infección Hospitalaria/epidemiología , Brotes de Enfermedades , Infecciones por Salmonella/epidemiología , Salmonella enterica/enzimología , Salmonella enterica/aislamiento & purificación , beta-Lactamasas/análisis , Antibacterianos/farmacología , Análisis por Conglomerados , Infección Hospitalaria/microbiología , Farmacorresistencia Bacteriana , Electroforesis en Gel de Campo Pulsado , Genotipo , Humanos , Epidemiología Molecular , Tipificación Molecular , Reacción en Cadena en Tiempo Real de la Polimerasa , Infecciones por Salmonella/microbiología , Salmonella enterica/clasificación , Salmonella enterica/efectos de los fármacos , Centros de Atención Terciaria , Estados Unidos/epidemiología , beta-Lactamasas/genéticaRESUMEN
OBJECTIVE Nosocomial outbreaks caused by Salmonella are rare. We describe the investigation and control of a cluster of novel extended-spectrum ß-lactamase (ESBL) Salmonella enterica serotype Isangi in a hospital in southeastern Michigan. METHODS An epidemiologic investigation, including case-control study, assessment of infection control practices and environmental cultures, was performed to identify modes of transmission. Healthcare workers (HCWs) exposed to case patients were screened. Strain relatedness was determined using pulsed-field gel electrophoresis (PFGE); ESBL confirmation was conducted using real-time PCR. Control measures were implemented to prevent further transmission. RESULTS Between September 2 and October 22, 2015, 19 surgical patients, including 10 organ transplant recipients and 1 HCW, had positive S. Isangi cultures. Of these case patients and HCW, 13 had gastroenteritis, 2 had bacteremia, 1 had surgical-site infection, and 4 were asymptomatic. Pulsed-field gel electrophoresis (PFGE) showed 89.5% similarity among the isolates in these cases. Isolates with resistant-phenotypes possessed plasmid-mediated CTX-M15 ESBL. A total of 19 case patients were compared with 57 control participants. Case patients had significantly higher odds of exposure to an intraoperative transesophageal (TEE) probe (adjusted odds ratio 9.0; 95% confidence interval, 1.12-72.60; P=.02). Possible cross-transmission occurred in the HCW and 2 patients. Cultures of TEE probes and the environment were negative. The outbreak ended after removal of TEE probes, modification of reprocessing procedures, implementation of strict infection control practices, and enhanced environmental cleaning. CONCLUSIONS We report the first nosocomial ESBL S. Isangi outbreak in the United States. Multiple control measures were necessary to interrupt transmission of this gastrointestinal pathogen. Exposure to possibly contaminated TEE probes was associated with transmission. Periodic monitoring of reprocessing procedures of TEE probes may be required to ensure optimal disinfection. Infect Control Hosp Epidemiol 2016;37:954-961.
Asunto(s)
Infección Hospitalaria/epidemiología , Brotes de Enfermedades , Complicaciones Posoperatorias/epidemiología , Infecciones por Salmonella/epidemiología , Serogrupo , beta-Lactamasas/aislamiento & purificación , Adulto , Anciano , Anciano de 80 o más Años , Infección Hospitalaria/prevención & control , Estudios Epidemiológicos , Femenino , Humanos , Masculino , Michigan/epidemiología , Persona de Mediana Edad , Infecciones por Salmonella/prevención & control , Adulto JovenRESUMEN
Methicillin-resistant Staphylococcus aureus (MRSA) USA300 clone is commonly found in the community and is being increasingly reported in the healthcare setting. A retrospective analysis was conducted to compare the epidemiology and outcomes between community-associated (CA) and healthcare-associated (HA) USA300 MRSA infections. The study enrolled 160 subjects with USA300 MRSA infections (47.5% CA-MRSA and 52.5% HA-MRSA). Failure in the HA group was higher (38.1%) compared with the CA group (23.7%) (P=0.05). Predictors of failure included male gender, age, presence of any co-morbidity, coronary artery disease, chronic kidney disease, history of MRSA, previous admission, fluoroquinolone exposure, HA infection and osteomyelitis (PAsunto(s)
Antibacterianos/uso terapéutico
, Infecciones Comunitarias Adquiridas/epidemiología
, Infección Hospitalaria/epidemiología
, Staphylococcus aureus Resistente a Meticilina/aislamiento & purificación
, Infecciones Estafilocócicas/epidemiología
, Adulto
, Técnicas de Tipificación Bacteriana/métodos
, Infecciones Comunitarias Adquiridas/tratamiento farmacológico
, Infecciones Comunitarias Adquiridas/microbiología
, Infección Hospitalaria/tratamiento farmacológico
, Infección Hospitalaria/microbiología
, Femenino
, Genotipo
, Humanos
, Masculino
, Staphylococcus aureus Resistente a Meticilina/clasificación
, Staphylococcus aureus Resistente a Meticilina/genética
, Persona de Mediana Edad
, Estudios Retrospectivos
, Factores de Riesgo
, Infecciones Estafilocócicas/tratamiento farmacológico
, Infecciones Estafilocócicas/microbiología
, Resultado del Tratamiento