Carol E. Chenoweth

Biofilms and catheter-associated urinary tract infections

Urinary catheter-related infections are commonly seen in several different patient populations and lead to substantial morbidity. The overall health care costs caused by these infections are sizable given how often urinary catheters are used in acute care settings, extended care facilities, and in persons with injured spinal cords. Recent attention has appropriately focused on biofilm development on the catheter surface because biofilm has important implications for the pathogenesis, treatment, and prevention of catheter-related infection. Because the most important risk factor for infection is duration of catheterization, indwelling urethral catheterization should be avoided or at least limited whenever possible. Additional methods to prevent this infection include aseptic insertion and maintenance use of a closed drainage system, anti-infective catheters in patients at high-risk for infection, and systemic antibiotics in select patients. Alternative urinary collection strategies may be appropriate in certain patient groups. Specifically, condom catheters should be considered in men likely to be adherent with this urinary collection method, suprapubic catheters should be considered in patients requiring long-term indwelling drainage, and intermittent catheterization seems appropriate in patients with injured spinal cords. Future research should focus on additional methods for preventing this common infection.

Evaluation of Hospital Room Assignment and Acquisition of Clostridium difficile Infection

BACKGROUND AND OBJECTIVE Clostridium difficile spores persist in hospital environments for an extended period. We evaluated whether admission to a room previously occupied by a patient with C. difficile infection (CDI) increased the risk of acquiring CDI. DESIGN Retrospective cohort study. SETTING Medical intensive care unit (ICU) at a tertiary care hospital. METHODS Patients admitted from January 1, 2005, through June 30, 2006, were evaluated for a diagnosis of CDI 48 hours after ICU admission and within 30 days after ICU discharge. Medical, ICU, and pharmacy records were reviewed for other CDI risk factors. Admitted patients who did develop CDI were compared with admitted patients who did not. RESULTS Among 1,844 patients admitted to the ICU, 134 CDI cases were identified. After exclusions, 1,770 admitted patients remained for analysis. Of the patients who acquired CDI after admission to the ICU, 4.6% had a prior occupant without CDI, whereas 11.0% had a prior occupant with CDI (P = .002). The effect of room on CDI acquisition remained a significant risk factor (P = .008) when Kaplan-Meier curves were used. The prior occupants CDI status remained significant (p = .01; hazard ratio, 2.35) when controlling for the current patients age, Acute Physiology and Chronic Health Evaluation III score, exposure to proton pump inhibitors, and antibiotic use. CONCLUSIONS A prior room occupant with CDI is a significant risk factor for CDI acquisition, independent of established CDI risk factors. These findings have implications for room placement and hospital design.

Do physicians examine patients in contact isolation less frequently? A brief report

BACKGROUND Patients who are hospitalized and infected with multidrug-resistant bacteria are usually placed in contact isolation, which requires hospital personnel to gown and glove before patient examination. Contact isolation with active culture surveillance appears beneficial in preventing the spread of drug-resistant infections; however, contact isolation may impede the ability to examine patients as a result of the additional effort required to gown and glove. We assessed whether patients who are hospitalized and placed under contact precautions are examined less often by second- and third-year medical residents (ie, senior medical residents), and attending physicians during morning rounds. METHOD We conducted a prospective cohort study on the inpatient medical services at 2 university-affiliated medical centers. We directly observed senior medical residents and attending physicians during morning rounds, and recorded the contact precaution status of the patient and whether they were examined by either physician. RESULTS Of a total of 139 patients, 31 (22%) were in contact isolation. Senior medical residents examined 26 of 31 patients (84%) in contact isolation versus 94 of 108 patients (87%) not in contact isolation (relative risk, 0.96; 95% confidence interval, 0.81-1.14; P =.58). In comparison, attending physicians examined 11 of 31 patients (35%) in contact isolation versus 79 of 108 patients (73%) not in contact isolation (relative risk, 0.49; 95% confidence interval, 0.30-0.79; P <.001). DISCUSSION Attending physicians are about half as likely to examine patients in contact isolation compared with patients not in contact isolation.

Colonization and Infection with Antibiotic‐Resistant Bacteria in a Long‐Term Care Facility

OBJECTIVE: To assess colonization and infection with methicillin‐resistant Staphylococcus aureus (MRSA), high‐level gentamicin‐resistant enterococci (R‐ENT) and gentamicin and/or ceftriaxone‐resistant Gram‐negative bacilli (R‐GNB) and the factors that are associated with colonization and infection with these organisms.

Risk Factors for Candidemia in a Children's Hospital

Candida species are increasingly important nosocomial pathogens in critically ill children. A 2.3-fold increase in the rate of nosocomial candidemia at our 200-bed tertiary care childrens hospital prompted a study to identify risk factors for this infection. Twenty-six cases were identified between 1992 and 1993, representing 21% of all nosocomial bloodstream infections. Candida albicans was the most frequent isolate (58%), followed by Candida parapsilosis (27%). A case-control study revealed that there was a statistically significant association between the occurrence of candidemia and placement of a central venous catheter in the femoral vein (P = .03), the use of a tunneled central venous catheter (P = .05), and prolonged hyperalimentation (P = .04). Patients with candidemia also were noted to have candiduria more often than controls (P = .003) and were more likely to have had topical antifungal agents prescribed (P = .04). Multivariate analysis showed that hyperalimentation was an independent risk factor for the development of candidemia. We conclude that measures must be taken to reduce these risk factors whenever possible.

Vancomycin-Resistant Enterococcal Colonization and Infection in Liver Transplant Candidates and Recipients: A Prospective Surveillance Study

BACKGROUND Vancomycin-resistant enterococcal (VRE) infections cause significant morbidity and mortality among patients undergoing liver transplantation. We performed a prospective study among patients awaiting transplantation to assess rates, risk factors, and outcomes associated with VRE colonization before and after transplantation. METHODS All adults on the transplantation waiting list from 2000-2003 were eligible. Demographic, historical, and laboratory data, as well as stool samples to be analyzed for VRE, were collected at enrollment and every 4-6 months thereafter until transplantation. After transplantation, samples were obtained every 3 days during hospitalization and were analyzed for VRE; outcomes were assessed at 90 days. RESULTS Overall, 375 patients were enrolled in our study, and 142 received transplants. VRE colonization occurred in 50 (13%) of 375 patients before transplantation and was independently associated with treatment with antianaerobic antimicrobials, third-generation cephalosporins, proton pump inhibitors, or neomycin; having a recent endoscopic retrograde cholangiopancreatogram or paracentesis procedure; and admission to the liver unit. Of these 50 patients, 22 (44%) received a transplant, and 7 (32%) of 22 developed a VRE infection after transplantation. An additional 22 patients (18%) who were not colonized before transplantation acquired VRE after transplantation; VRE infection developed in 5 (23%) of these patients. Patients colonized with VRE either before or after transplantation had longer stays in the intensive care unit and the hospital. Mortality at 90 days was significantly greater among those who acquired VRE after transplantation (5 [23%] of 22), compared with those who had VRE colonization before transplantation (2 [9%] of 22). CONCLUSIONS Liver transplantation candidates with VRE colonization before transplantation experience greater morbidity but not greater mortality, compared with noncolonized candidates. Transplant recipients who acquire VRE after transplantation have a higher mortality rate than noncolonized recipients. Strategies should be implemented to reduce nosocomial VRE acquisition after transplantation among this vulnerable group.

Detection of the Klebsiella pneumoniae Carbapenemase Type 2 Carbapenem-Hydrolyzing Enzyme in Clinical Isolates of Citrobacter freundii and K. oxytoca Carrying a Common Plasmid

ABSTRACT The Klebsiella pneumoniae carbapenemase (KPC) was detected in carbapenem-resistant isolates of Citrobacter freundii and Klebsiella oxytoca recovered from different patients in a Michigan hospital. Restriction analysis and hybridization with a KPC-specific probe showed the blaKPC-2 genes of these two genera of the family Enterobacteriaceae are carried on a common plasmid.

Risk Factors for Anaerobic Bloodstream Infections in Bone Marrow Transplant Recipients

The incidence of anaerobic bloodstream infections (BSI) in patients who underwent bone marrow transplantation (BMT) recently increased at our institution. A retrospective case-control study of patients undergoing BMT from January 1995 through December 1998 was performed to determine the microbiological characteristics, epidemiology, and outcome of anaerobic BSI and to identify independent risk factors for infection. Anaerobic BSI occurred in 23 patients, for a rate of 4 BSIs per 100 BMT procedures, and it accounted for 17% of all BSIs that occurred during the study period. Infection occurred at a mean (+/- standard deviation) of 7+/-4 days after BMT and 7+/-5 days after the onset of neutropenia. Fusobacterium nucleatum was the most frequently isolated pathogen (in 17 patients), followed by Leptotrichia buccalis (in 4), Clostridium septicum (in 1), and Clostridium tertium (in 1). Two case patients (9%) died. Severity of mucositis was an independent predictor of anaerobic BSI (odds ratio, 4.4; P=.01). Controlling mucositis is critical for the prevention of anaerobic BSI in this patient population.

Bloodstream Infection, Venous Thrombosis, and Peripherally Inserted Central Catheters: Reappraising the Evidence

The widespread use of peripherally inserted central catheters (PICCs) has transformed the care of medical and surgical patients. Whereas intravenous antibiotics, parenteral nutrition, and administration of chemotherapy once necessitated prolonged hospitalization, PICCs have eliminated the need for such practice. However, PICCs may not be as innocuous as once thought; a growing body of evidence suggests that these devices also have important risks. This review discusses the origin of PICCs and highlights reasons behind their rapid adoption in medical practice. We evaluate the evidence behind 2 important PICC-related complications--venous thrombosis and bloodstream infections--and describe how initial studies may have led to a false sense of security with respect to these outcomes. In this context, we introduce a conceptual model to understand the risk of PICC-related complications and guide the use of these devices. Through this model, we outline recommendations that clinicians may use to prevent PICC-related adverse events. We conclude by highlighting important knowledge gaps and identifying avenues for future research in this area.

Nosocomial catheter-related bloodstream infections in a pediatric intensive care unit: Risk and rates associated with various intravascular technologies*

Objective Nosocomial bloodstream infections are associated with increased patient morbidity, mortality, and hospital costs. More than 90% of these infections are related to the use of intravascular catheter devices. This study was done to assess the risk and rates of catheter related-bloodstream infections (CR-BSI) associated with different intravascular technologies in a pediatric intensive care unit population. Design Retrospective cohort study. Setting A 16-bed pediatric intensive care unit in a tertiary children’s hospital. Study Population All admissions between July 1997 and December 1999 requiring placement of an intravascular access device for care were examined. Patients with CR-BSI were identified through ongoing surveillance using Centers for Disease Control/National Nosocomial Infections Surveillance System definitions for bloodstream infection. Interventions None. Measurements and Main Results Of the 2,728 admissions during the review period, 1,043 (38.3%) required placement of an intravascular access device. Bivariate analysis revealed that patients who required intravascular cannulae for extracorporeal life support had a 10-fold increased risk of developing a CR-BSI, and patients requiring vascular access for renal replacement therapy demonstrated a 4-fold increase in the risk of developing CR-BSI compared with the referent group. There was a significant increase in the CR-BSI rate associated with the use of more intravascular access devices per patient admission. Multivariate logistic regression identified the use of extracorporeal life support therapy and the total duration of use of intravascular access devices as significant independent predictors of CR-BSI when controlling for other predictors. Conclusion The use of extracorporeal life support therapy, the presence of multiple intravascular access devices, and the total duration of intravascular access device use were associated with an increase in the rate and risk of developing CR-BSI in our pediatric intensive care unit population. Larger, prospective studies may help elucidate additional factors responsible for these observations.