Association between antecedent intravenous antimicrobial exposure and isolation of vancomycin-resistant enterococci

Determinación de los factores de riesgo en sepsis por Enterococcus vancomicino resistente. Estudio de casos y controles en pacientes críticamente enfermos

Introducción: las infecciones causadas por Enterococcus resistente a Vancomicina (EVR) presentan mayor mortalidad en pacientes críticos, asociado a un aumento gradual en este patrón de resistencia, especialmente en el continente americano, por lo cual la adecuada terapia antimicrobiana empírica es fundamental para mejorar los desenlaces. Objetivo: determinar los factores de riesgo asociados al desarrollo de infección por EVR en pacientes sépticos en la Unidad de Cuidados Intensivos (UCI) del Hospital San José en Bogotá, Colombia. Métodos: Estudio descriptivo de casos y controles en pacientes sépticos ingresados a la UCI durante 2016 y 2017. Los casos se definieron como pacientes con infección por EVR y los controles los pacientes con infección por otro germen. Resultados: se incluyeron 32 pacientes con aislamiento de EVR y 96 controles. Los factores de riesgo asociados a infección por EVR fueron: nutrición parenteral(OR 15,7 IC 4,2-71,4), lavado peritoneal (OR 8,9 IC 3,2-24,8), cultivo polimicrobiano (OR 19,9 IC 6,0-83,4). La mortalidad fue 56,2% en casos y 33,3% en controles. Conclusiones: Los factores de riesgo hallados con mayor frecuencia fueron: múltiples lavados peritoneales, nutrición parenteral y cultivos polimicrobianos. Encontramos una correlación significativa en el uso de antibiótico empírico adecuado y la reducción en la mortalidad.

Outcomes for and Risk Factors Associated With Vancomycin-ResistantEnterococcus faecalisand Vancomycin-ResistantEnterococcus faeciumBacteremia in Cancer Patients

Objective.

Vancomycin-resistant enterococci (VRE) are a major cause of nosocomial infection. We sought to compare vancomycin-resistant (VR)Enterococcus faecalisbacteremia and VREnterococcus faeciumbacteremia in cancer patients with respect to risk factors, clinical presentation, microbiological characteristics, antimicrobial therapy, and outcomes.

Methods.

We identified 210 cancer patients with VRE bacteremia who had been treated between January 1996 and December 2004; 16 of these 210 had VRE. faecalisbacteremia and were matched with 32 patients with VRE. faeciumbacteremia and 32 control patients. A retrospective review of medical records was conducted.

Results.

Logistic regression analysis showed that, compared with VRE. faecalisbacteremia, VRE. faeciumbacteremia was associated with a worse clinical response to therapy (odds ratio [OR], 0.3 [95% confidence interval (CI), 0.07-0.98];P= .046) and a higher overall mortality rate (OR, 8.3 [95% CI, 1.9-35.3];P= .004), but the VRE-related mortality rate did not show a statistically significant difference (OR, 6.8 [95% CI, 0.7-61.8];P= .09). Compared with control patients, patients with VRE. faecalisbacteremia were more likely to have received an aminoglycoside in the 30 days before the onset of bacteremia (OR, 5.8 [95% CI, 1.2-27.6];P= .03), whereas patients with VRE. faeciumbacteremia were more likely to have received a carbapenem in the 30 days before the onset of bacteremia (OR, 11.7 [95% CI, 3.6-38.6];P<.001). In a multivariate model that compared patients with VRE. faeciumbacteremia and control patients, predictors of mortality included acute renal failure on presentation (OR, 15.1 [95% CI, 2.3-99.2];P= .004) and VRE. faeciumbacteremia (OR, 11 [95% CI, 2.7-45.1];P<.001). No difference in outcomes was found between patients with VRE. faecalisbacteremia and control patients.

Conclusions.

VRE. faeciumbacteremia in cancer patients was associated with a poorer outcome than was VRE. faecalisbacteremia. Recent receipt of carbapenem therapy was an independent risk factor for VRE. faeciumbacteremia, and recent receipt of aminoglycoside therapy was independent risk factor forE. faecalisbacteremia.

Case-case-control study on factors associated with vanB vancomycin-resistant and vancomycin-susceptible enterococcal bacteraemia

Background

Enterococci are a major cause of healthcare-associated infection. In Australia, vanB vancomycin-resistant enterococci (VRE) is the predominant genotype. There are limited data on the factors linked to vanB VRE bacteraemia. This study aimed to identify factors associated with vanB VRE bacteraemia, and compare them with those for vancomycin-susceptible enterococci (VSE) bacteraemia.

Methods

A case-case-control study was performed in two tertiary public hospitals in Victoria, Australia. VRE and VSE bacteraemia cases were compared with controls without evidence of enterococcal bacteraemia, but may have had infections due to other pathogens.

Results

All VRE isolates had vanB genotype. Factors associated with vanB VRE bacteraemia were urinary catheter use within the last 30 days (OR 2.86, 95% CI 1.09-7.53), an increase in duration of metronidazole therapy (OR 1.65, 95% CI 1.17-2.33), and a higher Chronic Disease Score specific for VRE (OR 1.70, 95% CI 1.05-2.77). Factors linked to VSE bacteraemia were a history of gastrointestinal disease (OR 2.29, 95% CI 1.05-4.99) and an increase in duration of metronidazole therapy (OR 1.23, 95% CI 1.02-1.48). Admission into the haematology/oncology unit was associated with lower odds of VSE bacteraemia (OR 0.08, 95% CI 0.01-0.74).

Conclusions

This is the largest case-case-control study involving vanB VRE bacteraemia. Factors associated with the development of vanB VRE bacteraemia were different to those of VSE bacteraemia.

Epidemiology of vancomycin-resistant Enterococcus faecalis: a case-case-control study

Although much is known about vancomycin-resistant (VR) Enterococcus faecium, little is known about the epidemiology of VR Enterococcus faecalis. The predilection of VR E. faecalis to transfer the vancomycin resistance determinant to Staphylococcus aureus is much greater than that of VR E. faecium. The epidemiology of VR E. faecalis has important implications regarding the emergence of vancomycin-resistant S. aureus (VRSA); 8 of 13 reported VRSA cases have been from Michigan. A retrospective case-case-control study was conducted at the Detroit Medical Center, located in southeastern Michigan. Unique patients with VR E. faecalis infection were matched to patients with strains of vancomycin-susceptible (VS) E. faecalis and to uninfected controls at a 1:1:1 ratio. Five hundred thirty-two VR E. faecalis cases were identified and were matched to 532 VS E. faecalis cases and 532 uninfected controls. The overall mean age of the study cohort (n = 1,596) was 63.0 ± 17.4 years, and 747 (46.8%) individuals were male. Independent predictors for the isolation of VR E. faecalis (but not VS E. faecalis) compared to uninfected controls were an age of ≥65 years, nonhome residence, diabetes mellitus, peripheral vascular disease, exposure to cephalosporins and fluoroquinolones in the prior 3 months, and immunosuppressive status. Invasive procedures and/or surgery, chronic skin ulcers, and indwelling devices were risk factors for both VR E. faecalis and VS E. faecalis isolation. Cephalosporin and fluoroquinolone exposures were unique, independent predictors for isolation of VR E. faecalis. A majority of case patients had VR E. faecalis present at the time of admission. Control of VR E. faecalis, and ultimately VRSA, will likely require regional efforts focusing on infection prevention and antimicrobial stewardship.

A guide to antibiotics for the interventional radiologist

Antibiotics are among the most common pharmaceutical agents used by the interventional radiologist. This article updates some of the practical aspects of the use of antibiotics in interventional radiological practice and provides some general guidelines with respect to indications for and selection of antibiotics. In particular, the objectives of this article are to review the basic pharmacology of the common antibiotic agents, the interventional radiological procedures in which prophylactic antibiotics are usually administered, the specific antimicrobial agents recommended for prophylaxis before common interventional radiological procedures, the appropriate antibiotics for patients allergic to penicillins, and the indications for antibiotic prophylaxis to prevent bacterial endocarditis.

A prospective study of the impact of colonization following hospital admission by glycopeptide-resistant Enterococci on mortality during a hospital outbreak

BACKGROUND

This study was designed to investigate the impact on mortality of colonization by glycopeptide-resistant Enterococci (GRE) during hospitalization.

METHODS

Between 2004 and 2006, a hospital in Nancy, France, was subject to a GRE van A outbreak. Some 113 patients who had acquired GRE after hospital admission were matched with 113 controls. Basic demographic data, such as sex, age, principal pathology, history of surgery, and presence of associated pathology, were obtained for each case and control. Information on whether or not the case subject was still alive was obtained by searching the hospital mortality database and the civil death register and by phoning the patient's home. Statistical analysis used the Cox proportional hazards model for calculating survival function with SPSS software version 9.1 (SPSS Inc., Chicago, IL).

RESULTS

The mean age was 71.2 in the GRE+ group and 70.8 in the control group (P = .80). There was a significant difference between the groups for severity status health (P = .035). The mortality rate was 30.1% in the case group and 19.5% in the control group. Single predictor variable analysis showed a hazard ratio of death in the case group of 4.61 (95% confidence interval [CI]: 2.58-8.28], P = 2 x 10(-7)). The final Cox regression model with multiple predictor variables showed that only GRE presence (OR, 1.63 [95% CI: 1.04-2.57], P = .035) and severity of comorbidity (P = .013) were independently significant predictors of mortality.

CONCLUSION

This study shows that the GRE acquisition has a poor prognosis and that this is independent of the other prognostic factors such as age and severity of underlying disease. Survival in GRE+ patients was significantly shorter.

Post-surgical enterococcal meningitis: Clinical and epidemiological study of 20 cases

Enterococcal post-surgical meningitis is an uncommon disease. 20 episodes of nosocomial post-surgical enterococcal meningitis diagnosed between 1994 and 2003 were retrospectively studied. During the period of study 20 cases of post-surgical enterococcal meningitis (60% female, mean age 55+/-18 y, range 16-78 y) were reviewed. The mean time between admission at the hospital and surgery was 26 (SD = 15) d (range 7-61 d). The most frequent underlying diseases were: intracerebral haemorrhage (55%), brain neoplasms (25%), head trauma (15%) and hydrocephalus (5%). 11 patients had previously received antibiotic treatment. The isolates identified were Enterococcus faecalis (n = 18) (90%), E. faecium (1) and E. durans (1). 11 patients had polymicrobial infections. The treatment most frequently used was vancomycin alone or with other antibiotics (11). In 5 patients intrathecal vancomycin (20 mg/d) was also added. The mortality rate was not different in intrathecally treated patients. Cerebrospinal fluid (CSF) devices were removed in 8 patients. Four patients died due to the infection. Mortality was significantly associated with lack of removal of the CSF devices (p = 0.04). Enterococcal spp. are a cause of nosocomial meningitis associated with neurosurgical procedures and the presence of neurological devices.

Outbreak of vancomycin-resistant enterococcus colonization among pediatric oncology patients

OBJECTIVE

To detect the burden of vancomycin-resistant Enterococcus (VRE) colonization among pediatric oncology patients and to determine risk factors for VRE acquisition.

DESIGN

Retrospective case-control study.

SETTING

The Children's Hospital of Philadelphia.

PATIENTS

Pediatric oncology patients hospitalized from June 2006 through December 2007.

METHODS

Prevalence surveys revealed an increased VRE burden among pediatric oncology patients. For the case-control study, the 16 case patients were pediatric oncology patients who had 1 stool sample negative for VRE at screening before having a stool sample positive for VRE at screening; the 62 control patients had 2 consecutive screenings in which stool samples were negative for VRE. Case and control patients were matched on the duration of the interval between screens. Analyses were performed to determine the association between multiple exposures and VRE acquisition.

RESULTS

The prevalence survey revealed that 5 (9.6%) of 52 patients had unsuspected VRE colonization at the time of hospitalization. Multivariate analysis identified a lack of empirical contact precautions (odds ratio [OR], 17.16 [95% confidence interval {CI}, 1.49-198.21]; P= .02) and the presence of a gastrointestinal device (OR, 4.03 [95% CI, 1.04-15.56]; P= .04) as significant risk factors for acquisition of VRE. Observations in the interventional radiology department revealed that staff could not access the portions of the electronic medical record in which isolation precautions were documented. Simple interventions that granted access and that trained interventional radiology staff to review the need for precautions, coupled with enhanced infection control practices, interrupted ongoing transmission and reduced the proportion of VRE screens that were positive to 15 (1.2%) of 1,270.

CONCLUSIONS

Inadequate communication with regard to infection control precautions can increase the risk of transmission of epidemiologically important organisms, particularly when patients receive care at multiple clinic locations. Adherence to infection control practices across the spectrum of care may limit the spread of resistant organisms.

Vancomycin-resistant Enterococcus faecium infection in patients with hematologic malignancy: patients with acute myeloid leukemia are at high-risk

BACKGROUND

Vancomycin-resistant enterococci (VRE) are significant nosocomial pathogens in patients with hematologic malignancy. Identification of risk factors for infection is necessary for targeted prevention and surveillance.

OBJECTIVES AND METHODS

An outbreak of VRE infection occurred at a tertiary cancer hospital between 1 August 2003 and 30 June 2005. Infection control measures recommended by the Society for Healthcare Epidemiology of America were used throughout the outbreak period. A matched case-control study was performed to identify risk factors for VRE infection.

RESULTS

Fourteen VRE infections (13 episodes of bacteremia, one urinary tract infection) occurred a median of 10.5 d following hospital admission. All were due to Enterococcus faecium vanB. Univariate analysis identified the following variables to be significantly associated with VRE infection: presence of neutropenia, neutropenia >or=7 d, underlying diagnosis of acute myeloid leukemia (AML), and receipt of vancomycin, metronidazole or carbapenem antibiotic therapy in the 30 d prior to infection. On multivariate analysis, an underlying diagnosis of AML [odds ratio (OR), 15.00; P = 0.017] and vancomycin therapy during the previous 30 d (OR, 17.96; P = 0.036) were retained as independent risk factors for infection.

CONCLUSIONS

Risk stratification for development of VRE infection is possible for patients with hematologic malignancy. Patients with AML represent a high-risk population, and targeted prevention strategies must include improved antibiotic stewardship, particularly judicious use of vancomycin therapy.

The clinical impact of antibacterial prophylaxis and cycling antibiotics for febrile neutropenia in a hematological malignancy and transplantation unit

Febrile neutropenia is an expected complication during treatment of aggressive hematological malignancies and hematopoietic cell transplantation. We conducted a prospective cohort trial to determine the effects and safety of prophylactic fluoroquinolone administration, and rotation of empiric antibiotics for neutropenic fever in this patient population. From March 2002 through 2004, patients were treated with prophylactic levofloxacin during prolonged neutropenia, and a cycling schedule of empiric antibiotic therapy for neutropenic fever was initiated. The rates of bacteremia, resistance and complications were compared to a retrospective cohort of previously treated patients. The rate of gram-negative bacteremia decreased after the initiation of prophylactic levofloxacin (4.7 vs 1.8 episodes/1000 patient days, P<0.05). Gram-positive bacteremia rates remained unchanged, but more isolates of Enterococcus faecium were resistant to vancomycin after the intervention began. Resistance to the antibiotic agents used in the rotation did not emerge. There was no change in mortality during the intervention period. A prophylactic and cycling antibiotic schedule was successfully implemented on a hematological malignancy and hematopoietic cell transplant unit. gram-negative bacteremia was significantly decreased, without emergence of resistance. Concerns with Gram-positive resistance will require further observation.

Antibiotics and gastrointestinal colonization by vancomycin-resistant enterococci

Although several classes of antimicrobial agents have been associated with colonization or infection with glycopeptide-resistant enterococci (GRE) in individual clinical studies, the agents most commonly implicated are extended-spectrum cephalosporins and compounds with potent activity against anaerobic bacteria, including ticarcillin-clavulanic acid. In some clinical studies, formulary alterations designed to minimize the use of extended-spectrum cephalosporins or ticarcillin-clavulanic acid have resulted in significant decreases in colonization and infection by GRE. Experimental data using a mouse model of GRE gastrointestinal colonization indicate that persistence of high-level GRE colonization of the mouse gastrointestinal tract is promoted by exposure to agents with potent activity against anaerobic bacteria, suggesting that reduction of competing flora is the major factor leading to persistence of high-level colonization. One study performed in humans is consistent with this model and suggests that high levels of colonization may promote spread of resistant organisms in the nosocomial setting. Establishing colonization with GRE in uncolonized mice correlates with exposure to agents that are (a) secreted into the bile in significant concentrations and (b) have negligible activity against the colonizing enterococcal strain. Differences between piperacillin-tazobactam and ceftriaxone in the establishment model can be attributed directly to differences in their anti-enterococcal activity. Modification of antimicrobial prescribing practices may play an important role in facilitating successful infection control efforts to limit GRE in the nosocomial setting.

Effect of Hospitalization on the Antibiotic Resistance of FecalEnterococcus faecalisof Surgical Patients Over Time

The prevalence of antibiotic resistant Enterococcus faecalis was determined in fecal samples of 263 patients admitted to the surgical wards of three university-affiliated hospitals on admission, at discharge, and at 1 and 6 months after discharge. A slight increase in the prevalence of antibiotic resistance of E. faecalis was found at discharge for the antibiotics tested compared to those on admission, vancomycin excepted. At 6 months after discharge, the prevalence of resistance for amoxicillin (0%), ciprofloxacin (3%), erythromycin (47%), and oxytetracycline (60%) decreased to the level on admission (respectively 0%, 8%, 45%, and 64%). Gentamicin resistance was the same at discharge (10%) as 1 month later (12%), but decreased 6 months after discharge (8%) to the level on admission (7%). In conclusion, hospitalization resulted in the study population in a slight increase in the prevalence of resistant fecal E. faecalis isolates at discharge, which decreased again (slowly) to the level on admission 6 months after discharge. Thus, the influence of hospitalization on the prevalence of antibiotic resistance in the extramural situation disappears between 1 and 6 months after discharge in this population.

Treatment of pediatric febrile neutropenia in the era of vancomycin-resistant microbes

PURPOSE

The increasing frequency of Gm(+) infections in febrile neutropenic (FN) patients has resulted in increased use of vancomycin (VN). Likely as a result, VN-resistant Enterococcus (VRE) has become a significant concern in FN patients. We sought to understand how the emergence of VN resistant microbes has changed the antibiotic management of pediatric FN.

METHODS

A questionnaire was distributed by e-mail to responsible investigators of the Children's Oncology Group.

RESULTS

One hundred and thirty responses were analyzed. Forty-four percent initially used monotherapy, with 82% of those using ceftazidime. Twenty-seven used VN with another agent, generally ceftazidime. After the emergence of VRE and VN-resistant staphylococcus (VRS), monotherapy increased to 58%. Ceftazidime continued to be most frequently used. There was a 57% reduction in the use of VN with 88% of centers not currently using VN in their initial treatment of FN. Forty-seven percent of the centers that continue to use VN have VRE, while 90% that have discontinued its use have VRE/VRS.

CONCLUSIONS

Ours is the first study to survey current practices in the treatment of pediatric FN and to document changes in practice patterns due to emerging antibiotic resistance patterns. We demonstrate increased use of monotherapy for FN, and a 57% decrease in the use of VN. Local considerations influence antibiotic choices with a significant difference in VRE prevalence between those centers that continue to use VN as compared to those that have discontinued it.