Blood drawn through valved catheter hub connectors carries a significant risk of contamination.

Infection Control became concerned when bloodstream infection (BSI) rates increased after implementing a needleless valved hub connector. During a 21-month period three different needleless catheter hub connectors were evaluated by quantitatively culturing blood drawn through hub connectors that would have ordinarily been discarded (DBC). DBC drawn through Clearlink™ catheter hub connectors were found to be twice as likely to be positive as DBC drawn through Clave® or Q-syte™ hub connectors (P < 0.04). DBC grew pathogens 46% of the time and skin organisms 54% of the time. Patients with positive DBC were three times more likely to meet Centers for Disease Control (CDC) BSI criteria by DBC cultures than by physician-ordered blood cultures (CBC; P < 0.001). For patients growing pathogens in DBC, 64% had no CBC drawn, the average temperature was lower than for patients with pathogens in CBC (99.3 ± 1.5 ve 100.6 ± 1.9, P = 0.015), and 92% of discharged patients (11 out of 12) were not treated with an antibiotic active against the DBC pathogen. Drawing BC through a catheter hub connector carries a risk of false-positives that could increase BSI rates by up to 3-fold. Further work is necessary to evaluate this concern.

A randomized crossover study of silver-coated urinary catheters in hospitalized patients.

BACKGROUND: Urinary tract infections (UTIs) account for 30% to 40% of nosocomial infections resulting in morbidity, mortality, and increased length of hospital stay. OBJECTIVE: To assess the efficacy of a silver-alloy, hydrogel-coated latex urinary catheter for the prevention of nosocomial catheter-associated UTIs. METHODS: A 12-month randomized crossover trial compared rates of nosocomial catheter-associated UTI in patients with silver-coated and uncoated catheters. A cost analysis was conducted. RESULTS: There were 343 infections among 27,878 patients (1.23 infections per 100 patients) during 114,368 patient-days (3.00 infections per 1000 patient-days). The relative risk of infection per 1000 patient-days was 0.79 (95% confidence interval, 0.63-0.99; P =.04) for study wards randomized to silver-coated catheters compared with those randomized to uncoated catheters. Infections occurred in 291 of 11,032 catheters used on study units (2.64 infections per 100 catheters). The relative risk of infection per 100 silver-coated catheters used on study wards compared with uncoated catheters was 0.68 (95% confidence interval, 0.54-0.86; P =.001). Fourteen catheter-associated UTIs (4.1%) were complicated by secondary bloodstream infection. One death appeared related to the secondary infection. Estimated hospital cost savings with the use of the silver-coated catheters ranged from $14,456 to $573,293. CONCLUSIONS: The risk of infection declined by 21% among study wards randomized to silver-coated catheters and by 32% among patients in whom silver-coated catheters were used on the wards. Use of the more expensive silver-coated catheter appeared to offer cost savings by preventing excess hospital costs from nosocomial UTI associated with catheter use. Arch Intern Med. 2000;160:3294-3298.

Can antibiotic-resistant nosocomial infections be controlled?

Three decades ago infection-control programmes were created to control antibiotic-resistant nosocomial infections, but numbers of these infections have continued to increase, leading many to question whether control is feasible. Meticillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci were major problems during the 1990s. Many hospitals have tried antibiotic control but with limited efficacy against these pathogens. Studies of antibiotic restriction, substitution, and cycling have been promising, but more definitive data are needed. Increased compliance with hand hygiene would help but is unlikely to control this problem alone as a result of frequent contamination of other surfaces even when hands are cleansed and high transmission rates when hand hygiene is neglected. For 17 years, the Centers for Disease Control and Prevention have recommended contact precautions for preventing nosocomial spread of important antibiotic-resistant pathogens. Many studies confirm that this approach works when sufficient active-surveillance cultures are undertaken to detect the reservoir for spread. However, most healthcare facilities have not yet tried this approach.

Pseudoepidemic of streptococcal pharyngitis in a hospital pharmacy.

CONTEXT: Streptococcus pyogenes has recently re-emerged as a significant pathogen causing disease ranging from pharyngitis to lethal systemic infection. Six hospital pharmacy employees were diagnosed as having streptococcal pharyngitis during 1 week, and antibiotic prophylaxis was requested to halt the outbreak. OBJECTIVE: Outbreak investigation. DESIGN: Review of initial cases and prospective evaluation of the remaining pharmacy employees and the antigen detection test being used. SETTING: Pharmacy and occupational health department of a university hospital. POPULATION: Sixteen employees of the hospital pharmacy and 19 other employees of the hospital. RESULTS: The 6 pharmacy employees who had positive streptococcal antigen detection tests did not have symptoms suggesting streptococcal pharyngitis. Of the 10 remaining pharmacy employees, none had a positive throat culture for S pyogenes. Specificity of the antigen detection test being used was 53% (95% CI, 30%-75%) in prospective evaluation. CONCLUSIONS: This was believed to represent a pseudoepidemic because none of the 6 cases had signs or symptoms typical of streptococcal pharyngitis, none of the remaining 10 pharmacy employees had positive throat cultures, and prospective evaluation found low specificity of the antigen detection test. Whereas use of an accurate test in such a low prevalence setting could have resulted in a higher percentage of results being false-positive, the low specificity of the antigen detection test being used also contributed to the pseudoepidemic.

Prediction of poorer prognosis by infection with antibiotic-resistant gram-positive cocci than by infection with antibiotic-sensitive strains.

HYPOTHESES: Surgical patients with antibiotic-resistant gram-positive coccal (GPC) infections have a poorer prognosis than those with antibiotic-sensitive GPC infections, and colonization with resistant GPC predisposes to the development of resistant GPC infections. DESIGN: All infections among surgical patients from December 1, 1996, to December 1, 1998, were followed up prospectively. Patients with antibiotic-sensitive and antibiotic-resistant GPC infections were compared. Cohorts were also subdivided on the basis of GPC species, colonization status, and immunosuppression. SETTING: The surgical wards and intensive care units of a tertiary care, university hospital. MAIN OUTCOME MEASURES: In-hospital mortality, inhospital mortality during antibiotic therapy, length of stay, and length of stay from the time of initiation of antibiotics to discharge. RESULTS: Antibiotic-resistant GPC infection compared ki4th antibiotic-sensitive GPC infection was associated with a higher mortality and previous colonization rate (25.8% and 31.0% vs 17.6% and 8.8%, respectively; P = .04 and P<.001, respectively) and a markedly longer length of stay (55.0 +/- 3.3 vs 31.0 +/- 2.0 days; P<.001). Length of stay and treatment to discharge times were longer after resistant Staphylococcus aureus infections than after resistant Staphylococcus epidermidis infections. The mortality and length of stay of patients with gentamicin-resistant or vancomycin-resistant enterococcal infections were equivalently higher than those with antibiotic-sensitive enterococcal infections. Transplant recipients with resistant enterococcal infection had the highest mortality (41.9%). CONCLUSIONS: Surgical patients who develop antibiotic-resistant GPC infections have a significantly higher mortality rate, longer length of stay, and longer treatment to discharge time than patients with antibiotic-sensitive GPC infections. Colonization with resistant GPC predisposes to resistant GPC infection. Gentamicin-resistant enterococcus appears to be as virulent as vancomycin-resistant enterococcus.

Cost-effectiveness of active surveillance cultures and contact/droplet precautions for control of methicillin-resistant Staphylococcus aureus.

Some have reported that adopting Centers for Disease Control and Prevention guidelines requiring contact precautions for methicillin-resistant Staphylococcus aureus (MRSA) had no impact on rates of nosocomial spread or infection, and may therefore waste money. The objective of the present study was to evaluate the cost-effectiveness of active surveillance cultures and barrier precautions for controlling MRSA. Estimated costs of surveillance cultures and isolation measures used during an MRSA outbreak at this hospital were compared with the estimated attributable excess costs of methicillin resistance (i.e., the difference between MRSA and methicillin-sensitive S. aureus costs) for bacteraemias occurring during an MRSA outbreak not promptly controlled at another hospital. The study was set in the neonatal intensive care units of two tertiary care hospitals. Estimated costs of controlling the 10.5-month outbreak in this neonatal intensive care unit that resulted in 18 colonized and four infected infants ranged from $48 617 to $68 637. The estimated attributable excess cost of 75 MRSA bacteraemias in a second neonatal intensive care unit outbreak that resulted in 14 deaths and lasted 51 months was $1 306 600. Weekly active surveillance cultures and isolation of patients with MRSA halted an outbreak at this hospital, and cost 19- to 27-fold less than the attributable costs of MRSA bacteraemias in another outbreak that was not promptly controlled. The costs of infections at other body sites and the human cost of deaths from infection were not estimated but would further help to justify the cost of identifying colonized patients and implementing effective preventive measures.

Methodological principles of case-control studies that analyzed risk factors for antibiotic resistance: a systematic review.

Case-control studies that analyze the risk factors for antibiotic-resistant organisms have varied epidemiological methodologies, which may lead to biased estimates of antibiotic risk factors. A systematic review of case-control studies that analyzed risk factors for antibiotic-resistant organisms addressed 3 methodological principles: method of control group selection, adjustment for time at risk, and adjustment for comorbid illness. A total of 406 abstracts were reviewed. Thirty-seven studies met the inclusion and exclusion criteria and were reviewed and evaluated for the 3 methodological principles. Thirteen (35%) of 37 studies chose the preferred control group. Eleven adjusted for time at risk. Twenty-seven adjusted for comorbid illness. Future studies need to consider more closely the optimization of control group selection, adjusting for confounding caused by time at risk, and adjusting for confounding caused by comorbid illness.