RESUMO
Background: Percutaneous tracheostomy placement is a common procedure performed in the intensive care unit. The use of an anterior neck ultrasound exam is routinely performed preprocedure, allowing for vessel visualization in determining the safety and feasibility of performing the procedure bedside. This prospective observational cohort study was conducted to determine whether vasculature in the anterior neck, seen on bedside ultrasound exam, contributes to bleeding complications during or after percutaneous tracheostomy (PCT) placement. Research Question: Do the vessels identified on preprocedure neck ultrasound affect the risk of bleeding during and after bedside PCT placement? Study Design and Methods: Preprocedural ultrasound was used to identify standard anatomical landmarks and vascular structures in the anterior neck in all patients undergoing bedside PCT placement under bronchoscopic guidance. A blinded survey of our recorded preprocedural images was provided to an expert panel who regularly perform bedside PCTs to determine the influence the images have on their decision to perform the procedure at the bedside. Results: One out of 15 patients (7%) had intra-operative minimal bleeding which was not clinically significant and resolved by gauze compression for 30â s. None of the patients had post-procedural bleeding after tracheostomy placement. Based on the blinded interpretation of neck ultrasound, there was 0.214 inter-operator variability among the expert panelists for decision-making regarding performing bedside PCT. Interpretation: Vessels visualized with anterior neck ultrasound were found to be small venous structures and did not significantly contribute to bleeding risk in patients who underwent PCT placement. The size and location of veins on neck ultrasound may commonly contribute to abandoning bedside PCT. This study suggests that veins measuring 3.9â mm or smaller identified at the site of access do not increase the risk of bleeding in PCT placement.
Assuntos
Unidades de Terapia Intensiva , Traqueostomia , Humanos , Traqueostomia/efeitos adversos , Traqueostomia/métodos , Estudos Prospectivos , Ultrassonografia , Procedimentos Cirúrgicos VascularesRESUMO
BACKGROUND: To compare the complication rates of urgent endotracheal intubation (UEI) performed by pulmonary critical care medicine (PCCM) fellows and attending intensivists using a direct laryngoscope (DL) versus a video laryngoscope (VL) in a medical intensive care unit (MICU). METHODS: We studied all UEIs performed from November 2008 through July 2012 in an 18-bed MICU in a university-affiliated hospital. All UEIs were performed by 15 PCCM fellows or attending intensivists using only the DL from November 2008 through February 2010 and the VL from March 2010 to July 2012. Throughout the entire study period, the UEI team leader recorded complications of the procedure using a standard data collection form immediately following the completion of the procedure. This permitted a comparison of complication rates between the DL and the VL. RESULTS: A total of 140 UEIs were performed using the DL and 252 using the VL. Using the DL, the esophageal intubation rate was 19% and the difficult intubation rate was 22%; using the VL, the esophageal intubation rate was 0.4% and the difficult intubation rate was 7%. There was no significant difference in the rate of severe hypotension, severe desaturation, aspiration, dental injury, airway injury, or death between the 2 groups. CONCLUSION: The use of the VL for UEI performed by PCCM fellows is associated with a reduction in the rate of esophageal intubation and difficult endotracheal intubation when compared to the use of the DL.
Assuntos
Cuidados Críticos/métodos , Intubação Intratraqueal/efeitos adversos , Intubação Intratraqueal/métodos , Laringoscopia , Cirurgia Vídeoassistida , Idoso , Atitude do Pessoal de Saúde , Competência Clínica , Desenho de Equipamento , Feminino , Humanos , Unidades de Terapia Intensiva , Intubação Intratraqueal/estatística & dados numéricos , Laringoscopia/instrumentação , Laringoscopia/métodos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Resultado do TratamentoRESUMO
PURPOSE: Propofol is known to provide excellent intubation conditions without the use of neuromuscular blocking agents. However, propofol has adverse effects that may limit its use in the critically ill patients, particularly in the hemodynamically unstable patient. We report on the safety and efficacy of propofol for use as an agent for urgent endotracheal intubation (UEI) in the critically ill patients. METHODS: We reviewed the outcomes of 472 consecutive UEIs performed by a medical intensive care unit (ICU) team at a tertiary care hospital from November 2008 through November 2012. Outcome data were collected prospectively as part of an ongoing quality improvement project. RESULTS: Propofol was used as the sole sedative agent in 409 (87%) of the 472 patients. In 18 (4%) of the 472 patients, other agents (midazolam, lorazepam, or etomidate) were used in addition to propofol. Of the 472, 10 (2%) intubations were performed with a sedative agent other than propofol, and 35 (7%) of the 472 intubations were performed without any sedating agent. Endotracheal tube insertion was successful in all 472 patients. Complications of UEI in those patients who received propofol were as follows: desaturation (Sao 2 < 80%) 30 (7%) of the 427, hypotension (systolic blood pressure < 70 mm Hg) 19 (4%) of the 427, difficult intubation (>2 attempts) 44 (10%) of the 427, esophageal intubation 24 (6%) of the 427, aspiration 6 (1%) of the 427, and oropharyngeal injury 4 (1%) of the 427. There were no deaths. Average dose of propofol was 99 mg (standard deviation 7.39) per person. CONCLUSIONS: Our results compare favorably with the complication rate of UEI reported in the critical care and anesthesiology literature and indicate that propofol is a useful agent for airway management in the ICU.
Assuntos
Anestésicos Intravenosos/administração & dosagem , Anestésicos Intravenosos/efeitos adversos , Cuidados Críticos , Intubação Intratraqueal/métodos , Propofol/administração & dosagem , Propofol/efeitos adversos , Idoso , Atitude do Pessoal de Saúde , Estudos de Casos e Controles , Lista de Checagem , Competência Clínica , Cuidados Críticos/métodos , Estado Terminal , Feminino , Humanos , Unidades de Terapia Intensiva , Masculino , Guias de Prática Clínica como Assunto , Estudos Prospectivos , Resultado do Tratamento , Estados Unidos/epidemiologiaRESUMO
PURPOSE: Sympathetic activation induced by sleep-disordered breathing may contribute to cardiovascular morbidity. However, the apnea-hypopnea index (AHI) excludes respiratory effort-related arousals (RERAs) associated with inspiratory flow limitation without oxygen desaturation. We sought to determine whether RERAs are associated with sympathetic activation. METHODS: Twenty-five adults (12 males, 13 females) with AHI < 10/h and RERA index >5/h were included in this study. Power spectral density analysis was performed on two non-contiguous 10-min segments containing inspiratory flow limitation and arrhythmia-free electrocardiogram during N2 sleep. One segment contained RERA; the other did not, NO-RERA. Spectral power was described in a low-frequency domain (LF; 0.04-0.15 Hz), primarily sympathetic modulation, and a high frequency domain (HF; 0.15-0.4 Hz), parasympathetic modulation. RESULTS: Analyses of LF and HF powers were made using normalized and absolute values. LF power was greater during RERA compared to NO-RERA (50.3 vs. 30.1 %, p < 0.001) whereas HF power was greater during NO-RERA compared to RERA (69.9 vs. 49.7 %, p < 0.001). The LF/HF ratio was greater during RERA than NO-RERA (1.01 vs. 0.43, p < 0.001). Gender differences emerged using absolute values of power: The percentage increase in LF power during RERA relative to NO-RERA was significantly greater for females than males, 247.6 vs. 31.9 %, respectively (p < 0.02). CONCLUSIONS: RERAs are associated with a marked increase in cardiac sympathetic modulation, especially in females. Patients with a high RERA index, even in the setting of a low or normal AHI, may be exposed to elevated sympathetic tone during sleep.
Assuntos
Resistência das Vias Respiratórias/fisiologia , Nível de Alerta/fisiologia , Frequência Cardíaca/fisiologia , Inalação/fisiologia , Apneia Obstrutiva do Sono/fisiopatologia , Sistema Nervoso Simpático/fisiopatologia , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Oxigênio/sangue , Polissonografia , Processamento de Sinais Assistido por Computador , Apneia Obstrutiva do Sono/diagnósticoRESUMO
Organizing pneumonia (OP), characterized histopathologically by patchy filling of alveoli and bronchioles by loose plugs of connective tissue, may be seen in a variety of conditions. These include but are not limited to after an infection, drug reactions, radiation therapy, and collagen vascular diseases. When a specific cause is responsible for this entity, it is referred to as "secondary OP." When an extensive search fails to reveal a cause, it is referred to as "cryptogenic OP" (previously called "bronchiolitis obliterans with OP"), which is a clinical, radiologic, and pathologic entity classified as an interstitial lung disease. The clinical presentation of OP often mimics that of other disorders, such as infection and cancer, which can result in a delay in diagnosis and inappropriate management of the underlying disease. The radiographic presentation of OP is polymorphous but often has subpleural consolidations with air bronchograms or solitary or multiple nodules, which can wax and wane. Diagnosis of OP sometimes requires histopathologic confirmation and exclusion of other possible causes. Treatment usually requires a prolonged steroid course, and disease relapse is common. The aim of this article is to summarize the clinical, radiographic, and histologic presentations of this disease and to provide a practical diagnostic algorithmic approach incorporating clinical history and characteristic imaging patterns.
Assuntos
Bronquiolite Obliterante , Pneumonia em Organização Criptogênica , Doenças Pulmonares Intersticiais , Pneumonia , Bronquiolite Obliterante/complicações , Pneumonia em Organização Criptogênica/diagnóstico por imagem , Pneumonia em Organização Criptogênica/etiologia , Humanos , Pulmão/patologia , Doenças Pulmonares Intersticiais/complicações , Pneumonia/complicaçõesRESUMO
OBJECTIVE: The aim of this study was to assess any association between use of inhaled corticosteroids (ICS) and tracheobronchomalacia (TBM). METHODS: This study was a retrospective analysis of patients with asthma and COPD, with and without TBM. Patients were diagnosed with TBM on the basis of CT imaging, flexible bronchoscopy, or both. Patients were deemed to be on ICS if they had been receiving treatment for at least 3 months. Simple logistic regression models were used to assess the association between TBM status and each proposed factor. A multivariable logistic regression model was used to assess the association between TBM and steroid dose. RESULTS: A total of 463 patients with COPD (n = 153) and asthma (n = 310) were studied. In multivariate analysis, the odds of TBM were 3.5 times higher in patients on high-dose steroids compared with patients not on steroids (OR, 3.5; 95% CI, 1.4-8.5; P = .007). Age (P < .0001), presence of gastroesophageal reflux disease (P < .0001), use of long-acting muscarinic antagonists (P < .0001), and type of pulmonary disease (P = .002) were also associated with TBM. In patients using ICS, the odds of having TBM were 2.9 times greater in patients on high-dose inhaled steroids compared with those on low-dose inhaled steroids (OR, 2.9; 95% CI, 1.2-7.1; P = .02). Age (P = .003), presence of gastroesophageal reflux disease (P = .002), use of long-acting muscarinic antagonists (P = .004), type of ICS (P = .04), and number of months on ICS (P < .0001) were all associated with TBM. CONCLUSIONS: There was a significant association between ICS use in higher doses for a longer duration of time with TBM. Prospective randomized controlled trials are needed to show causality of this observed association.
Assuntos
Asma/tratamento farmacológico , Glucocorticoides/administração & dosagem , Doença Pulmonar Obstrutiva Crônica/tratamento farmacológico , Traqueobroncomalácia/diagnóstico , Administração por Inalação , Idoso , Asma/complicações , Broncoscopia , Progressão da Doença , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Doença Pulmonar Obstrutiva Crônica/complicações , Estudos Retrospectivos , Tomografia Computadorizada por Raios X , Traqueobroncomalácia/complicaçõesRESUMO
BACKGROUND: Competence in advanced critical care transesophageal echocardiography allows the intensivist to diagnose and manage cardiopulmonary failure when transthoracic echocardiography is not sufficient to answer the clinical question. This report describes the feasibility, safety, and utility of transesophageal echocardiography performed by pulmonary and critical care fellows in a medical ICU in critically ill patients who were mechanically ventilated. METHODS: This longitudinal descriptive study of advanced transesophageal echocardiography was performed in patients who were mechanically ventilated. The complications and clinical utility of the examinations were abstracted from review of the image set, the written report, and the patient chart. Influence on diagnosis was classified as confirming the initial clinical diagnosis or identification of a new or unanticipated finding. Therapeutic impact was categorized as no change in therapy resulting from the study findings or as change in therapy resulting from the study findings. RESULTS: The examination was feasible in all patients in whom it was attempted, and there were no complications of the procedure. New or actionable findings were identified in 43 (28%) studies, and 109 (72%) studies confirmed the initial clinical diagnosis. The findings resulted in a change in clinical management in 58 (38%) patients. CONCLUSIONS: Critical care transesophageal echocardiography is feasible, safe, and has clinical utility. It can be safely and effectively performed by fellows within the context of their critical care training with faculty supervision. Pulmonary critical care fellowship training programs should consider introducing critical care transesophageal echocardiography as a useful clinical tool.
Assuntos
Cuidados Críticos/métodos , Estado Terminal , Ecocardiografia Transesofagiana/estatística & dados numéricos , Educação de Pós-Graduação em Medicina/métodos , Unidades de Terapia Intensiva , Internato e Residência , Pneumologia/educação , Ecocardiografia Transesofagiana/normas , Estudos de Viabilidade , Feminino , Seguimentos , Humanos , Pneumopatias/diagnóstico , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos TestesRESUMO
RATIONALE: Critical care nurses are an integral part of rapid response (RR) teams. The length of time they spend away from an intensive care unit (ICU) to attend RRs and how ICU nurses perceive the time away from the ICU has not been previously evaluated. OBJECTIVES: To determine: (1) the time an ICU nurse spends at RRs; (2) ICU nurses' view of nursing absence; and (3) RR characteristics associated with longer nursing time. METHODS: A prospective analysis of RRs in one 500-bed adult academic medical center over 1 year. Nurses' perception was assessed through surveys and semistructured interviews. MEASUREMENTS AND MAIN RESULTS: There were 536 RRs. An ICU nurse was present for 20 minutes or less in 54% of the RRs, 21-40 minutes in 26%, 41-60 minutes in 11%, and more than 60 minutes in 9% of RRs. Compared with nursing time required in RRs for neurologic instability (median [Q1 first quartile {25th percentile}, Q3 third quartile {75th percentile}] = 15.0 [10.0, 27.0] min), nursing time was longer in RRs for hemodynamic instability (30.0 [15.0, 45.0] min) and respiratory failure (25.0 [12.0, 45.0] min; P < 0.0001). Of the 85 nurses surveyed, 47% considered 41-60 minutes as a substantial amount of time at RRs; 99% perceived ICU workload as busier when a nurse attended RRs, and 87% believed ICU care was compromised, defined as reduction in the quality of care. CONCLUSIONS: In this study of one midsized academic medical center, about half of critical care nurse involvement in RRs takes them away from their ICU patients for less than 20 minutes. Nevertheless, nurses felt that ICU care was compromised when an ICU nurse responded to an RR.
Assuntos
Atitude do Pessoal de Saúde , Cuidados Críticos , Emergências/enfermagem , Equipe de Respostas Rápidas de Hospitais/normas , Unidades de Terapia Intensiva , Papel do Profissional de Enfermagem , Avaliação de Resultados em Cuidados de Saúde , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , New York , Estudos Prospectivos , Fatores de Tempo , Recursos Humanos , Adulto JovemRESUMO
PURPOSE: Aspiration of gastric contents is a dangerous complication of urgent endotracheal intubation (UEI). Left upper quadrant (LUQ) ultrasonography may have the potential to decrease this complication by identifying patients with gastric fluid content, thereby allowing the UEI team to evacuate gastric contents prior to intubation. METHODS: This was an observational study of 80 UEIs where LUQ ultrasonography was performed in a medical intensive care unit of a tertiary care hospital. The subjects were 80 patients requiring UEI. Gastric fluid content was identified as an anechoic or hypoechoic space in the appropriate anatomic position. If potentially consequential fluid was identified, it was evacuated using a gastric tube. Repeat LUQ ultrasonography confirmed removal of gastric contents prior to induction. RESULTS: A total of 80 patients had LUQ ultrasonography performed; 19 (24%) had gastric fluid content identified and 13 (16%) had sufficient gastric fluid content such that the UEI team proceeded with gastric tube insertion. Following gastric fluid removal, repeat ultrasonography showed absence of gastric fluid. Gastric fluid volume removed was 553 ± 290 ml (mean ± standard deviation, SD). None of the 80 patients had a clinically consequential aspiration event. Performance of ultrasonography took fewer than 2 min. No patient had complication related to the ultrasonography or removal of gastric contents. CONCLUSIONS: Ultrasonography is useful for the detection of gastric fluid. This technique may have utility in reducing risk of a clinically consequential aspiration event during UEI.
Assuntos
Cuidados Críticos , Suco Gástrico/diagnóstico por imagem , Intubação Intratraqueal , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Conteúdo Gastrointestinal , Humanos , Unidades de Terapia Intensiva , Masculino , Pessoa de Meia-Idade , Aspiração Respiratória , Gestão da Segurança , Ultrassonografia , Adulto JovemRESUMO
BACKGROUND: Chest compressions (CCs) are a critical part of cardiopulmonary resuscitation. We studied the presence and duration of adequate CCs performed by medical housestaff, and correlated our findings with gender and body mass index. METHODS: Fifty-eight first-postgraduate-year medical housestaff performed CCs on a computerized patient simulator equipped with a calibrated CC measurement device. Following initial testing, subjects were trained to perform adequate CCs. Subjects were retested 2 weeks later. Presence and duration of adequate CCs were measured during a 120-second endurance test. RESULTS: Before training, 14/28 (50%) of the male housestaff performed adequate CCs and 0/30 (0%) of the female housestaff performed adequate CCs. After training, 25/28 (89%) of the male housestaff and 16/30 (53%) of the female housestaff performed adequate CCs. Body mass index and height were not related to adequacy of CCs. After training, 7/28 (25%) of the male subjects and 1/30 (3%) of the female subjects were able to maintain adequate CCs for 120 seconds. CONCLUSIONS: Training housestaff on a patient simulator is an effective means of improving the adequacy of CCs. Despite training, a significant number of women were unable to perform adequate CCs compared with men; body mass index and height were not determining factors. Very few housestaff were able to sustain 120 seconds of adequate CCs, despite training.
Assuntos
Reanimação Cardiopulmonar/educação , Reanimação Cardiopulmonar/estatística & dados numéricos , Corpo Clínico Hospitalar/educação , Corpo Clínico Hospitalar/estatística & dados numéricos , Tórax/fisiologia , Índice de Massa Corporal , Simulação por Computador , Feminino , Humanos , Capacitação em Serviço , Masculino , Manequins , Fatores SexuaisRESUMO
A high level of gastrointestinal colonization frequently precedes invasive infection due to Enterococcus faecium. Factors other than antimicrobial resistance that promote gastrointestinal colonization by E. faecium have not been identified. We tested the ability of a colonization-proficient clinical E. faecium isolate (C68) to transfer colonizing ability to noncolonizing E. faecium recipient strains. Transconjugants derived from matings that used E. faecium D344SRF as a recipient strain colonized mouse gastrointestinal tracts in high numbers under selective pressure from clindamycin or vancomycin, compared with control strains that lacked DNA transferred from C68. We transferred DNA into a second recipient strain (E. faecium GE-1), which also colonized mice in significantly greater numbers under selective pressure from clindamycin, compared with a control strain. These results indicate that E. faecium clinical isolates express transmissible factors other than antimicrobial resistance that promote colonization of the mouse gastrointestinal tract.
Assuntos
Enterococcus faecium/fisiologia , Gastroenteropatias/microbiologia , Transferência Genética Horizontal , Infecções por Bactérias Gram-Positivas/microbiologia , Animais , Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Modelos Animais de Doenças , Farmacorresistência Bacteriana/genética , Enterococcus faecium/efeitos dos fármacos , Enterococcus faecium/genética , Feminino , Regulação Bacteriana da Expressão Gênica , Genes Bacterianos , Camundongos , Testes de Sensibilidade Microbiana , Seleção Genética , Vancomicina/farmacologiaAssuntos
Edema Pulmonar/complicações , Sons Respiratórios/etiologia , Cardiomiopatia de Takotsubo/complicações , Ecocardiografia , Feminino , Humanos , Pessoa de Meia-Idade , Edema Pulmonar/diagnóstico por imagem , Insuficiência Respiratória/etiologia , Insuficiência Respiratória/fisiopatologia , Sons Respiratórios/fisiopatologia , Cardiomiopatia de Takotsubo/diagnóstico por imagem , Disfunção Ventricular Esquerda/fisiopatologiaRESUMO
To test the hypothesis that establishing gastrointestinal colonization with multiresistant Enterococcus faecium (VRE) C68 results from expansion of the enterococcal population in the upper small bowel, we compared VRE quantities recovered from the proximal, middle, and distal segments of the small bowel from mice treated with different antimicrobial agents. Antibiotics associated with high-level VRE fecal colonization (cefotetan, ceftriaxone, clindamycin, and ticarcillin-clavulanic acid) increased VRE quantities in all small-bowel segments, whereas cefepime and piperacillin-tazobactam did not. Enterococcal expansion did not correlate with reductions in numbers of native gram-negative or anaerobic flora. Green fluorescence protein-expressing E. faecium bacteria were found adjacent to the small bowel epithelial lining in colonized mice. These data indicate that enterococcal bowel colonization begins within the proximal small bowel and does not correlate with inhibition of other cultivable flora. Host or enterococcal factors induced by exposures to certain antibiotics may play a role in facilitating E. faecium colonization of the mammalian gastrointestinal tract.
Assuntos
Antibacterianos/farmacologia , Enterococcus faecium/efeitos dos fármacos , Enterococcus faecium/crescimento & desenvolvimento , Intestino Delgado/efeitos dos fármacos , Intestino Delgado/microbiologia , Animais , Cefalosporinas/farmacologia , Ácidos Clavulânicos/farmacologia , Clindamicina/farmacologia , Farmacorresistência Bacteriana Múltipla , Escherichia coli/crescimento & desenvolvimento , Escherichia coli/metabolismo , Proteínas de Fluorescência Verde/biossíntese , Metronidazol/farmacologia , Camundongos , Ácido Penicilânico/análogos & derivados , Ácido Penicilânico/farmacologia , Piperacilina/farmacologia , Combinação Piperacilina e Tazobactam , Ticarcilina/farmacologiaRESUMO
Using 15 unrelated Enterococcus faecium isolates as donors, we demonstrated that ampicillin resistance was transferable to an E. faecium recipient containing a pbp5 deletion for all but four strains. The transfers occurred at low frequencies (generally ca. 10(-9) transconjugants/recipient CFU), consistent with chromosome-to-chromosome transfer. pbp5 transfer occurred within large genetic regions, and insertion into the recipient genome occurred most commonly into the recipient SmaI restriction fragment that had been created by the previous pbp5 deletion. Restriction mapping of the region upstream of pbp5 revealed a commonality of fragment sizes among the clinical isolates from the United States which differed significantly from those of three strains that were isolated from turkey feces. These data prove conclusively that E. faecium pbp5 is a transferable determinant, even in the absence of a coresiding vancomycin resistance mobile element. They also suggest that the spread of high-level ampicillin resistance among U.S. E. faecium strains is due in part to the transfer of low-affinity pbp5 between clinical isolates.
Assuntos
Conjugação Genética , Enterococcus faecium/genética , Proteínas de Ligação às Penicilinas/genética , Resistência Microbiana a Medicamentos/genética , Enterococcus faecium/efeitos dos fármacos , Vancomicina/farmacologiaRESUMO
We studied the effect of different subcutaneously administered beta-lactam antibiotics on the establishment of gastrointestinal colonization by vancomycin-resistant Enterococcus faecium C68 in a mouse model. Aztreonam, cefazolin, cefepime, and, to a lesser extent, ceftazidime, which neither have significant antienterococcal activity nor are secreted into human bile at high concentrations, did not promote significant vancomycin-resistant enterococci (VRE) colonization. Piperacillin-tazobactam, which has antienterococcal activity and is secreted in human bile at high concentrations, inhibited colonization after limited exposure to the inoculum but was associated with progressively increased VRE colony counts in stool samples after repeated exposure to the VRE inoculum. Ceftriaxone and cefotetan, which lack antienterococcal activity but are secreted into human bile at high concentrations, were associated with rapid and high-level colonization. These data suggest that the risk of VRE colonization varies during exposure to different beta-lactam antimicrobial agents and that the risk is related to biliary concentration and antienterococcal activity of the specific beta-lactam.