Risk of vancomycin-resistant Enterococcus (VRE) bloodstream infection among patients colonized with VRE.

BACKGROUND: Colonization with vancomycin-resistant Enterococcus (VRE) is a risk factor for subsequent VRE bloodstream infection (BSI); however, risk factors for BSI among colonized patients have not been adequately described. We sought to determine the proportion of VRE-colonized patients who subsequently develop VRE BSI and to identify risk factors for VRE BSI among these patients. METHODS: Records of 768 patients colonized with VRE from January 2002 through June 2005 were reviewed. The proportion of patients who developed VRE BSI was calculated, and the characteristics of these patients were compared, in a 2:1 ratio, with those of patients who did not develop VRE BSI. To identify risk factors for VRE BSI and for death, we used univariate logistic regression analysis and then multivariate logistic regression analysis. Using pulsed-field gel electrophoresis (PFGE), we compared the isolate recovered when the patient was colonized and the isolate recovered when the patient developed VRE BSI. RESULTS: Of the 768 patients colonized with VRE, 31 (4.0%) developed VRE BSI. Multivariate analysis identified the following independent risk factors for developing VRE BSI: infection of an additional body site other than blood (adjusted odds ratio [aOR], 3.9; P = .04), admission to the hospital from a long-term care facility (aOR, 12.6; P = .04), and receipt of vancomycin (aOR, 10.6; P = .001). The independent risk factors for death among patients colonized with VRE were immunosuppression (aOR, 12.9; P = .001) and VRE BSI (aOR, 9.1; P = .002). Of the 31 patients who developed VRE BSI, 23 (74%) had a pair of isolates representing VRE colonization and VRE BSI. For 19 (83%) of these 23 patients, the isolate representing BSI was genetically related to the isolate representing VRE colonization: 12 pairs of isolates (52%) had identical banding patterns, 5 had closely related patterns, and 2 had possibly related patterns. CONCLUSION: Of the 768 patients colonized with VRE, 31 (4.0%) usually developed VRE BSI due to a related strain. Independent risk factors for BSI among colonized patients were admission from a long-term care facility, infection of an additional body site, and exposure to vancomycin. Independent risk factors for death were immunosuppression and VRE BSI.     

Risk factors for vancomycin-resistant Enterococcus (VRE) infection in colonized patients with cancer.

To determine the risk factors for vancomycin-resistant Enterococcus (VRE) infection in colonized patients with cancer, we conducted a case-control study. According to multivariate analysis, the only significant factors were neutropenia (< 500 cells/mm3) for more than 1 week and the use of oral vancomycin. Therefore, colonized neutropenic patients with cancer who have previously used oral vancomycin are most prone to VRE infection.     

Colonization and infection with multiple nosocomial pathogens among patients colonized with vancomycin-resistant Enterococcus.

OBJECTIVE: To test the hypothesis that patients colonized with vancomycin-resistant Enterococcus (VRE) have a higher frequency of colonization or infection with other nosocomial pathogens than do patients who are not colonized with VRE. DESIGN: A rectal swab culture survey was conducted to determine the point-prevalence of stool colonization with ceftazidime-resistant gram-negative bacilli in hospitalized patients with or without VRE stool colonization. For a 6-month period, the frequency of Clostridium difficile diarrhea and isolation of antibiotic-resistant (ie, ceftazidime-, piperacillin/tazobactam-, levofloxacin-, or trimethoprim/sulfamethoxazole-resistant) gram-negative bacilli, methicillin-resistant Staphylococcus aureus (MRSA), and non-albicans Candida species from clinical specimens other than stool was examined. SETTING: A Department of Veterans Affairs medical center. PATIENTS: All patients hospitalized in the acute care facility and one nursing home unit during a 1-week period in February 2001. RESULTS: VRE-colonized patients had a higher point-prevalence of rectal colonization with ceftazidime-resistant gram-negative bacilli than did patients not colonized with VRE (17% vs 4%; P = .026). During a 6-month period,the VRE-colonized patients were more likely to have Clostridium difficile-associated diarrhea (26% vs 2%; P = .001), MRSA infection (17% vs 4%; P = .017), or colonization or infection with gram-negative bacilli resistant to 4 different antibiotics. CONCLUSION: VRE-colonized patients in our institution have a higher frequency of colonization or infection with other nosocomial pathogens than do patients who are not colonized with VRE. This suggests that isolation measures implemented to control VRE could help limit the dissemination of other, coexisting pathogens.     

Risk of environmental and healthcare worker contamination with vancomycin-resistant enterococci during outpatient procedures and hemodialysis.

OBJECTIVE: To assess the risk of environmental and healthcare worker (HCW) contamination with vancomycin-resistant enterococci (VRE) during outpatient procedures performed on fecally continent patients currently colonized with VRE (cVRE) or previously colonized with VRE (pVRE). DESIGN: Observational study. SETTING: Outpatient consultation and radiology rooms and the hemodialysis unit in a university teaching hospital. PATIENTS: Fecally continent cVRE and pVRE patients. INTERVENTIONS: Both cVRE and pVRE patients attended standardized mock outpatient consultations and routine hemodialysis sessions in an area that had been thoroughly cleaned and microbiologically confirmed to be free of VRE contamination. After each session, the patient, environment, and participating HCW were tested for VRE contamination. RESULTS: Fourteen cVRE patients participated in 49 mock outpatient consultation sessions and radiology sessions or 26 actual hemodialysis sessions, and 7 pVRE patients participated in 28 outpatient consultation sessions. Sessions with cVRE patients had higher rates of contamination of the environment (chair cultures were positive for VRE in 36% of outpatient consultation sessions, 58% of hemodialysis sessions; couch cultures were positive in 48% of outpatient consultation sessions, 42% of radiology sessions, and 45% of hemodialysis sessions), contamination of HCW gowns (gown cultures were positive in 20% of outpatient consultation sessions, 4% of radiology sessions, and 30% of hemodialysis sessions), and contamination of patients' own hands (hand cultures were positive in 36% of outpatient consultation sessions, 25% of radiology sessions, and 54% of hemodialysis sessions). Overall, contamination rates associated with pVRE patients attendance at outpatient consultations were 12% of those noted for cVRE patients (odds ratio, 0.10; 95% confidence interval, 0.03-0.42; P = .001). CONCLUSIONS: Given the nature of the contamination risk posed by fecally continent cVRE patients undergoing outpatient procedures, infection control measures should focus on effective HCW and patient hand hygiene and chair and couch cleaning, to minimize transmission of VRE.     

Factors associated with acquisition of vancomycin-resistant enterococci (VRE) in roommate contacts of patients colonized or infected with VRE in a tertiary care hospital.

OBJECTIVE: Most nosocomial acquistion of vancomycin-resistant enterococci (VRE) is due to cross-transmission. We sought to identify risk factors for acquisition of VRE by roommates of patients colonized or infected with VRE. DESIGN: Retrospective cohort study. SETTING: A 472-bed tertiary care teaching hospital. METHODS: All patients who shared a room with a patient colonized or infected with VRE at our hospital between January 1, 1999 and December 31, 2006 were identified. These roommates of VRE-positive patients were screened by rectal swab culture on days 2, 5, and 7 after the last exposure to the index patient. Chart reviews were performed to identify risk factors for VRE colonization in these roommates. RESULTS: Eighty-eight roommates of patients colonized or infected with VRE were identified. Of the 38 roommates with complete follow-up, 8 (21%) became colonized with VRE. These 8 roommates were older (median, 87.5 vs 62.5 years of age; P = .001), had longer duration of room exposure (median, 8.5 vs 4 days; P = .002), and were more likely to have a urinary catheter (odds ratio [OR], 16 [95% confidence interval {CI}, 1.7-152]; P = .005), an elevated serum creatinine level (OR, 17 [95% CI, 1.4-196]; P = .02), low serum albumin level (OR, 9.9 [95% CI, 1.3-113]; P = .01), and recent third-generation cephalosporin use (OR, 8.3 [95% CI, 1.5-47]; P = .02). CONCLUSION: Roommates of patients identified as colonized or infected with VRE are at substantial risk of becoming colonized, with the degree of risk increasing in older and more frail patients. VRE control programs should pay particular attention to such patients.     

Colonization of patients and contamination of the patients' environment by MRSA under conditions of single-room isolation

Meticillin-resistant Staphylococcus aureus (MRSA) are endemic in hospitals worldwide and present a major concern in hospital hygiene. The aim of the present study was to investigate the relationship between patients' MRSA colonization of the body and the frequency of environmental contamination. Twenty-five MRSA-positive hospitalized surgical patients and their environment in isolation rooms were screened on four occasions over a 14-day period. Out of 1099 samples from patients, 330 (30.0%) were MRSA-positive. The median number of MRSA-positive body sites per screening decreased significantly from the 1st (3, range 1-9) to the 14th (2, range 0-9, p=0.011) day of isolation. Contamination was found in 45% of the 100 environmental sampling dates and MRSA was detected in a low proportion of the 1000 environmental surface samples: 105/1000 (10.5%). The number of positive results for each sampling date decreased from the 1st (median 1, range 0-8) to the 14th (median 0, range 0-3, p=0.21) day of isolation. The results show a very strong correlation between the number of MRSA-positive body sites of individual patients and the MRSA contamination of the patient's hospital room (r=0.700, p<0.001). Pulsed-field gel electrophoresis (PFGE) analysis demonstrated a 98% agreement between patient and environmental samples. MRSA colonization of the groin area correlates most strongly with colonization of the body and environment. Seventy-five of 240 (31%) samples taken in rooms of patients with colonization of the groin were MRSA-positive, whereas only 27 of 760 (3.6%) samples taken in rooms of patients without colonization of the groin produced positive results (odds ratio 12.3; 95% confidence interval, 7.7-20). It is concluded that MRSA patients without colonization of the groin have a relatively low risk of environmental spread of MRSA and thus a reduced risk of transmission.     

Antianaerobic antibiotic therapy promotes overgrowth of antibiotic-resistant, gram-negative bacilli and vancomycin-resistant enterococci in the stool of colonized patients.

BACKGROUND AND OBJECTIVE: Antianaerobic antibiotic therapy promotes persistent high-density growth of vancomycin-resistant enterococci (VRE) in the stool of colonized patients. We tested the hypothesis that antibiotic regimens with potent antianaerobic activity promote overgrowth of coexisting antibiotic-resistant, gram-negative bacilli in the stool of VRE-colonized patients. DESIGN: Eight-month prospective study examining the effect of antibiotic therapy on the stool density of gram-negative bacilli resistant to ceftazidime, ciprofloxacin, or piperacillin/tazobactam. SETTING: A Department of Veterans Affairs medical center including an acute care hospital and nursing home. PATIENTS: All VRE-colonized patients with at least 3 stool samples available for analysis. RESULTS: One-hundred forty stool samples were obtained from 37 study patients. Forty-nine (61%) of 80 stool samples obtained during therapy with an antianaerobic regimen were positive for an antibiotic-resistant, gram-negative bacillus, where-as only 14 (23%) of 60 samples obtained 4 or more weeks after completion of such therapy were positive (P < .001). Twenty-four (65%) of the 37 patients had one or more stool cultures positive for a gram-negative bacillus resistant to ciprofloxacin, ceftazidime, or piperacillin/tazobactam. The density of these organisms was higher during therapy with antianaerobic regimens than in the absence of such therapy for at least 2 weeks (mean +/- standard deviation, 5.6 +/- 1.4 and 3.9 +/- 0.71 log10 organisms/g; P < .001). CONCLUSION: Limiting the use of antianaerobic antibiotics in VRE-colonized patients may reduce the density of colonization with coexisting antibiotic-resistant, gram-negative bacilli.     

Risk estimation of radioactive contamination after the Chernobyl accident using bioindicators.

After the Chernobyl nuclear accident, game meat and, in particular, sheep meat in the Republic of Croatia showed a high degree of radioactive contamination compared to large livestock. The activity concentrations of 131I, 134Cs, and 137Cs were measured in meat and internal organs (i.e., lung, liver, kidney, and heart) of game (e.g., venison, hare, and wild boar) and sheep that were used as biological indicators of radioactive contamination. In order to estimate the importance of game and sheep as a dietary source of radioactivity, the effective dose equivalent for the average and critical population (hunters and livestock raising families) were calculated. The data indicated that sheep meat represents greater risk for the human population, in case of a nuclear accident, than game meat. The share of meat from sheep (4.4%) prevailed over the share of meat from game (0.5%) when comparing the average intake of meat per inhabitant in Croatia. This result pointed to an increased risk for families who depend mostly on sheep meat in the case of a nuclear accident.     

Risk factors for infection and molecular typing in patients in the intensive care unit colonized with nosocomial Enterobacter aerogenes.

OBJECTIVES: To determine the frequency of colonization by Enterobacter aerogenes in patients in the intensive care unit (ICU) for more than 48 hours and to evaluate the risk factors for infection in patients colonized by this bacteria. DESIGN: An 8-month prospective study. SETTING: A 12-bed medical-surgical ICU in a 450-bed, university-affiliated, tertiary-care hospital in Belgium. METHOD: Pulsed-field gel electrophoresis was used to determine the genotypes of E. aerogenes isolates. RESULTS: We observed two major clones of E. aerogenes in the ICU. Interestingly, 87.5% of infected patients had the same genomic profile for colonization and infection. Risk factors for infection in this particular population included younger age, prolonged hospital stay, mechanical ventilation, and bronchoscopy. CONCLUSIONS: Colonization is a major prerequisite for infection. The identification of risk factors for infection in colonized patients can optimize the quality of treatment in the ICU.     

Evidence of delays in transferring patients with methicillin-resistant Staphylococcus aureus or vancomycin-resistant Enterococcus to long-term-care facilities.

This retrospective case-control study examined whether there was a difference in length of time awaiting long-term-care placement for patients identified as having methicillin-resistant Staphylococcus aureus or vancomycin-resistant Enterococcus compared to controls. Thirty-nine patients with methicillin-resistant Staphylococcus aureus or vancomycin-resistant Enterococcus waited for placement an average of 61 days longer than controls (P<.0002). The average number of requests for placement was 2.5 compared to 1.7 for controls (P=.015).     

Efficacy of glove combinations in reducing cell culture infection after glove puncture with needles contaminated with human immunodeficiency virus type 1.

OBJECTIVE: To study the effect of various latex and treated glove combinations in reducing the frequency of human immunodeficiency virus (HIV) infection of tissue culture cells after puncture by surgical needles contaminated with infectious human immunodeficiency virus type 1 (HIV-1). DESIGN: One, two, or three layers of sterile latex glove material, or two latex layers with intermediate cotton or Kevlar (with or without the virucidal compound nonoxynol-9) were used to cover 24-well cell culture dishes containing MT2 cells in cell culture medium. Surgical needles wet with cell culture medium containing HIV-1 (HTLV IIIA strain) were passed through the glove materials into the culture medium in the wells of the culture dishes. The culture medium in each well was then assayed biweekly for HIV-1 p24 antigen as a test for infection of cells in the well. RESULTS: The rate of HIV-1 infection of cell cultures after glove puncture was greater than 90% with a single latex surgical glove barrier, 23% to 60% with double or triple layers of latex gloves, less than 8% with an intermediate cotton glove impregnated with 4% nonoxynol-9, 6% with an intermediate Kevlar glove, and 0% with an intermediate Kevlar glove impregnated with nonoxynol-9. CONCLUSIONS: An intermediate glove of Kevlar or of Kevlar or cotton impregnated with virucidal compound nonoxynol-9 between standard latex gloves may improve surgical glove safety, compared with latex gloves alone with respect to needlestick transmission of HIV-1. The experimental model used may permit rapid investigation of other glove systems as barriers to the transfer of infectious agents through gloves by needlestick.     

Observance of hand washing procedures performed by the medical personnel after the patient contact. Part II

Objectives

The Centers for Disease Control and Prevention (CDC) as well as the World Health Organization (WHO) state that adequate hand hygiene maintained by medical personnel is an indispensable prerequisite for controlling nosocomial infections. The recommendations of CDC and WHO emphasize the obligation to wash hands after each contact with a patient, after the exposure to a potentially infectious material or upon the contact with objects surrounding the patient.

Materials and Methods

The study was performed by quasi-observation among the group of 188 medical staff members (nurses and physicians) working in three selected hospitals of the ?ód? Province. The procedure of hand washing/disinfection performed directly after the patient contact according to the recommendations of CDC and WHO was observed. The results were subject to statistical analysis (p < 0.05).

Results

During 1544 h of observations, 4101 activities requiring hand washing were recorded. The medical personnel followed the hand hygiene procedures after the patient contact in 26.4% of the situations that require hygiene according to the guidelines. The level of observance of the hand washing procedures depended significantly on the type of performed activity, profession, degree of workload, index of activity, and time of duty hours. The mean time of hand washing after patient contact was 9.2 s for physicians and 6.7 s for nurses.

Conclusion

Both the level of observance of hygienic procedures after the contact with patients as well as the time of hand washing are insufficient. There is an urgent need to work out educational programs on maintaining proper hand hygiene for medical personnel.     

Management of inpatients colonized or infected with antimicrobial-resistant bacteria in hospitals in the United States.

BACKGROUND: Although guidelines for multidrug-resistant organisms generally include recommendations for contact precautions and surveillance cultures, it is not known how frequently U.S. hospitals implement these measures on a routine basis and whether infectious diseases consultants endorse their use. METHODS: The Emerging Infections Network surveyed its members, infectious diseases consultants, to assess their use of and support for contact precautions and surveillance cultures for routine management of multidrug-resistant organisms in their principal inpatient workplace. Specifically, members were asked about use of these strategies for methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, and multidrug-resistant, gram-negative bacilli on general wards, ICUs, and transplant units. RESULTS: Overall, 400 (86%) of 463 respondents supported the routine use of contact precautions to control one or more multidrug-resistant organisms in at least one unit, and 89% worked in hospitals that use them. In contrast, 50% of respondents favored routine use of surveillance cultures to manage at least one multidrug-resistant organism in any unit, and 30% of respondents worked in hospitals that use them routinely in any unit. Members favored routine use of surveillance cultures significantly more in ICUs and transplant units than in general wards for each multidrug-resistant organism (P < .001). CONCLUSIONS: Most of the infectious diseases consultants endorsed the use of contact precautions for routine management of patients colonized or infected with multidrug-resistant organisms and work in hospitals that have implemented them. In contrast, infectious diseases consultants are divided about the role of routine surveillance cultures in multidrug-resistant organism management, and few work in hospitals that use them.     

Risk of bioaerosol contamination with Aspergillus species before and after cleaning in rooms filtered with high-efficiency particulate air filters that house patients with hematologic malignancy.

OBJECTIVE: To examine the impact of cleaning and directional airflow on environmental contamination with Aspergillus species in hospital rooms filtered with high-efficiency particulate air (HEPA) filters that house patients with hematologic malignancy. DESIGN: Detailed environmental assessment. SETTING: A 475-bed tertiary cancer center in the southern United States. METHODS: From April to October 2004, 1,258 surface samples and 627 bioaerosol samples were obtained from 74 HEPA-filtered rooms (in addition, 88 outdoor bioaerosol samples were obtained). Samples were collected from rooms cleaned within 1 hour after patient discharge and from rooms before cleaning. Positive and negative airflows were evaluated using air-current tubes at entrances to patient rooms. RESULTS: Of 1,258 surface samples, 3.3% were positive for Aspergillus species. Univariate analysis showed no relationship between cleaning status and occurrence of Aspergillus species. Of 627 bioaerosol samples, 7.3% were positive for Aspergillus species. Multiple logistic analysis revealed independently significant associations with detection of Aspergillus species. Cleaned rooms positive for Aspergillus species had a higher geometric mean density of colonies than that of rooms sampled before cleaning (18.9 vs 5.5 colony-forming units [cfu] per cubic meter; P=.0047). Rooms with positive airflow had a detection rate for bioaerosol samples equivalent to that of rooms with negative airflow (7.3% vs 7.8%; P=.8). There was no significant difference in the density of Aspergillus species between rooms with negative airflow and rooms with positive airflow (12.5 vs 8.4 cfu/m(3); P=.33). CONCLUSIONS: Concentration of bioaerosol contamination with Aspergillus species was increased in rooms sampled 1 hour after cleaning compared with rooms sampled before cleaning, suggesting a possible correlation between re-entrained bioaerosols (ie, those suspended by activity in the room) after cleaning and the risk of nosocomial invasive aspergillosis.     

Risk assessment of the occupational contact with ammonium

The aim of the cohort retrospective study was to analyze and evaluate the influence of certain factors (age, profession, smoking) on the characteristics and the incidence rate of the upper respiratory tract diseases (URTDs) in the occupational contact with ammonium. Subjects were 180 men, divided into 3 professional groups. The average shift concentrations of ammonium were measured in the permanent work places and individually by personal passive dosemeters. The URTDs were classified into 15 groups according to localization and the stage of the inflammatory process. The relationships "time-response" and "dose (concentration)-response" were determined. The factor "cumulative exposure" was used in order to evaluate the actual noxious effect of NH3 on the mucose of the upper respiratory tract (URT). There was a statistically reliable difference found in the incidence rate of atrophic rhinitis, hypertrophic pharyngitis and laryngitis, and neoplasms of the URT in the workers with the highest cumulative exposure. For this group relative risk was 4.00, 2.22, 3.20 and 4.00, respectively, with 95% Cl. The "cumulative exposure" factor gives the best proofs for the toxic effect of ammonium and a possibility for assessment of the relative risk.     

Duration of follow-up after contact with HIV: 3 or 6 months

The revised Netherlands guideline 'Sexually transmitted diseases and neonatal herpes' recommends shortening of the follow-up period from 6 to 3 months for HIV-testing after a risky contact and a period of 6 months in case of post-exposure prophylaxis. The newly adopted follow-up period has a precedent in Sweden, where, based on the same scientific arguments, the follow-up period has been reduced to 3 months. There is little scientific information on which to base the optimal duration of the follow-up period. Therefore, two different periods are used in the Netherlands: 3 months for medical practice in the field of sexually transmitted diseases and 6 months for occupational exposure of health care workers and for blood products.