Use of surveillance data to calculate the sample size and the statistical power of randomized clinical trials testing Staphylococcus aureus vaccine efficacy in orthopedic surgery.

BACKGROUND: Patients undergoing primary total hip arthroplasty (THA) would be a worthy population for anti-staphylococcal vaccines. The objective is to assess sample size for significant vaccine efficacy (VE) in a randomized clinical trial (RCT). METHODS: Data from a surveillance network of surgical site infection in France between 2008 and 2011 were used. The outcome was S. aureus SSI (SASSI) within 30 days after surgery. Statistical power was estimated by simulations repeated for theoretical VE ranging from 20% to 100% and for sample sizes from 250 to 8000 individuals per arm. RESULTS: 18,688 patients undergoing THA were included; 66 (0.35%) SASSI occurred. For a 1% SASSI rate, the sample size would be at least 1316 patients per arm to detect significant VE of 80% with 80% power. CONCLUSION: Simulations with real-life data from surveillance of hospital acquired infections allow estimation of power for RCT and sample size to reach the required power.

The "RESEAU MATER": An efficient infection control for endometritis, but not for urinary tract infection after vaginal delivery.

"RESEAU MATER" is useful to monitor nosocomial infections in maternity and contributes to the decreasing trend of it, since its implementation. Specifically, this network demonstrates its efficiency in the control of endometritis following vaginal deliveries, but not in the control of urinary tract infections. The aim of this study is to determine whether the difference between the control of endometritis and of urinary tract infection could be explained by an unsuitable regression model or by an unsuitable care policy concerning urinary cares. This study includes (1) the analysis of historic data of the network and (2) the description of French guidelines for maternity cares and available evaluations, concerning endometritis and urinary tract infection prevention. Univariate and multivariate odds ratios (ORs) were calculated for the total study period of 1999-2013, for these infections and their risk factors. The endometritis frequency is decreasing, in association with no significant evolution of associated risk factors, but urinary tract infection frequency is constant, in association with a increasing trend of its risk factors such as intermittent catheterization and epidural analgesia. In French guidelines, all preventive measures against endometritis are clearly broadcasted by all field operators, and repeated audits have reinforced the control of their application. But preventive measures against urinary tract infection seem to be broadcasted exclusively in the circle of infection prevention agencies and not in the obstetrics societies or in the Health Ministry communication. Urinary tract infection prevention requires a clearer public and professional policy in favor of a more efficient urinary cares, with a specific target to maternity.

Compliance with standard precautions: Results of a French national audit.

BACKGROUND: Standard precautions (SPs) aim to reduce the risk of cross-transmission of microorganisms. The objectives of the present study were to assess institutional policies for SPs promotion, available resources for SPs implementation, and education of health care workers (HCWs) and their compliance with SPs. METHODS: A multisite mixed-methods audit was conducted in 2011. Self-assessment questionnaires were administered at institution, ward, and HCW levels in French health care facilities (HCFs). Results were given as percentage of objectives achieved (POA) or percentage of "never or sometimes," "often," and "always" responses for each question. RESULTS: A total of 1599 HCFs participated, including 14,968 wards and 203,840 HCWs. At an institutional level, the POA was 88%, covering SPs promotion (91%), procedures (99%), and SPs evaluation (63%). At the ward level, the POA was 94%, covering procedures (95%) and resources (93%). HCWs reported the best compliance for changing gloves between patients (94.5% "always"), and the worst compliance for the use of gloves for intramuscular injection and the use of eye protection in cases of blood exposure risk (34.5% and 24.4% of "always," respectively). CONCLUSIONS: A literature review found no other study of SPs that included such a large study group. These results led to SPs promotion actions at local and regional levels. Reinforcement of SPs observance will be prioritized in the next national program from the French Ministry of Health.

Maternal infection rates after cesarean delivery by Pfannenstiel or Joel-Cohen incision: a multicenter surveillance study.

OBJECTIVE: Our purpose was to evaluate maternal nosocomial infection rates according to the incision technique used for caesarean delivery, in a routine surveillance study. STUDY DESIGN: This was a prospective study of 5123 cesarean deliveries (43.2% Joel-Cohen, 56.8% Pfannenstiel incisions) in 35 maternity units (Mater Sud Est network). Data on routine surveillance variables, operative duration, and three additional variables (manual removal of the placenta, uterine exteriorization, and/or cleaning of the parieto-colic gutter) were collected. Multiple logistic regression analysis was used to identify independent risk factors for infection. RESULTS: The overall nosocomial infection and endometritis rates were higher for the Joel-Cohen than Pfannenstiel incision (4.5% vs. 3.3%, 0.8% vs. 0.3%, respectively). The higher rate of nosocomial infections with the Joel-Cohen incision was due to a greater proportion of patients presenting risk factors (i.e., emergency delivery, primary cesarean, blood loss > or =800 mL, no manual removal of the placenta and no uterine exteriorization). However, the Joel-Cohen technique was an independent risk factor for endometritis. CONCLUSION: The Joel-Cohen technique is faster than the Pfannenstiel technique but is associated with a higher incidence of endometritis.

Reduction of urinary tract infections acquired in an intensive care unit during a 10-year surveillance program.

PURPOSE: To describe trends of urinary catheter-related infections (UCRIs) acquired by patients hospitalized in intensive care units (ICU) in relation with an infection control program. MATERIALS AND METHODS: Prospective surveillance in one ICU of a university hospital in Lyon (France) between 1995 and 2004. RESULTS: A 66% reduction of urinary catheter-related infections (UCRIs) acquired by patients hospitalized was observed between 1995 and 2004 after adjustment on age, gender, antibiotic use at admission, and duration of exposure to urinary catheter. CONCLUSIONS: These results, obtained by continuous epidemiological monitoring of nosocomial infections, are encouraging with regard to the improvement of infection control measures and the evolution of medical practices. Further studies in ICUs are needed to confirm this trend.

Decreased rates of nosocomial endometritis and urinary tract infection after vaginal delivery in a French surveillance network, 1997-2003.

OBJECTIVES: To identify independent risk factors for endometritis and urinary tract infection (UTI) after vaginal delivery, and to monitor changes in nosocomial infection rates and derive benchmarks for prevention. DESIGN: Prospective study. METHODS: We analyzed routine surveillance data for all vaginal deliveries between January 1997 and December 2003 at 66 maternity units participating in the Mater Sud-Est surveillance network. Adjusted odds ratios for risk of endometritis or UTI were obtained using a logistic regression model. RESULTS: The overall incidence rates were 0.5% for endometritis and 0.3% for UTI. There was a significant decrease in the incidence and risk of endometritis but not of UTI during the 7-year period. Significant risk factors for endometritis were fever during labor, parity of 1, and instrumental delivery and/or manual removal of the placenta. Significant risk factors for UTI were urinary infection on admission, premature rupture of membranes (more than 12 hours before admission), blood loss of more than 800 mL, parity of 1, instrumental delivery, and receipt of more than 5 vaginal digital examinations. Each maternity unit received a poster showing graphs of the number of expected and observed cases of UTI and endometritis associated with vaginal deliveries, which enabled each maternity unit to determine their rank within the network and to initiate prevention programs. CONCLUSIONS: Although routine surveillance means additional work for maternity units, our results demonstrate the usefulness of regular targeted monitoring of risk factors and of the most common nosocomial infections in obstetrics. Most of the information needed for monitoring is already present in the patients' records.

Effect of intrapartum antibiotic prophylaxis against group B streptococcal infection on comparisons of rates of endometritis and urinary tract infection in multicenter surveillance.

OBJECTIVE: To establish whether antibiotic prophylaxis against group B streptococcal infection may be a confounding factor in comparisons of rates of endometritis and urinary tract infection after vaginal delivery. DESIGN: Prospective study. SETTING: Maternity units at 48 hospitals in a regional surveillance network in France during 2001-2004. METHODS: The maternity units used a common protocol to establish whether antibiotic prophylaxis was indicated. Risk factors for endometritis and urinary tract infections were evaluated using multiple logistic regression. RESULTS: We analyzed 49,786 vaginal deliveries. The percentage of women receiving antibiotic prophylaxis varied widely and significantly among the maternity units (range, 4.4%-26.0%; median, 15.8%; 25th percentile, 12.1%; 75th percentile, 19.0%) (P < .001, by Mantel-Haenszel chi(2) test). The incidence rate of endometritis was significantly reduced from 0.25% to 0.11% by antibiotic prophylaxis (P = .001). There was a decrease in the incidence of urinary tract infection from 0.37% to 0.32%, but it was not statistically significant (P = .251). CONCLUSIONS: A reduction in the incidence of endometritis was observed when intrapartum antibiotic prophylaxis against group B streptococcal infection was used. However, the proportion of women considered to be at risk of infection varied widely among institutions. Comparisons of rates of endometritis among maternity units, but not urinary tract infection rates, should take into account antibiotic prophylaxis as a significant confounding factor.

Downward trends in surgical site and urinary tract infections after cesarean delivery in a French surveillance network, 1997-2003.

OBJECTIVE: To evaluate whether the adjusted rates of surgical site infection (SSI) and urinary tract infection (UTI) after cesarean delivery decrease in maternity units that perform active healthcare-associated infection surveillance. DESIGN: Trend analysis by means of multiple logistic regression. SETTING: A total of 80 maternity units participating in the Mater Sud-Est surveillance network. PATIENTS: A total of 37,074 cesarean deliveries were included in the surveillance from January 1, 1997, through December 31, 2003. METHODS: We used a logistic regression model to estimate risk-adjusted post-cesarean delivery infection odds ratios. The variables included were the maternity units' annual rate of operative procedures, the level of dispensed neonatal care, the year of delivery, maternal risk factors, and the characteristics of cesarean delivery. The trend of risk-adjusted odds ratios for SSI and UTI during the study period was studied by linear regression. RESULTS: The crude rates of SSI and UTI after cesarean delivery were 1.5% (571 of 37,074 patients) and 1.8% (685 of 37,074 patients), respectively. During the study period, the decrease in SSI and UTI adjusted odds ratios was statistically significant (R=-0.823 [P=.023] and R=-0.906 [P=.005], respectively). CONCLUSION: Reductions of 48% in the SSI rate and 52% in the UTI rate were observed in the maternity units. These unbiased trends could be related to progress in preventive practices as a result of the increased dissemination of national standards and a collaborative surveillance with benchmarking of rates.

Hepatitis C screening practices among private practitioners: impact of an information campaign.

OBJECTIVES: A campaign designed to enhance screening for hepatitis C virus infection (HCV) by private practitioners was conducted in the Lyon area from April 2000 to March 2001. The target population for screening was composed of individuals with active/previous intravenous drug abuse habits or had received blood products before 1991 or who presented elevated serum transaminase levels. The objectives of the present study were to validate the campaign's organization and its impact on screening practices. METHODS: The impact of the campaign was estimated from the number of prescribed and performed HCV screening and confirmation tests, the number of physicians who prescribed HCV screening tests, and the number of HCV screening tests prescribed by each physician. Indicators/practices observed during the 12-month campaign were compared with the same indicators/practices observed during the 12-month period preceding the campaign. RESULTS: During the campaign, 15952 HCV serology tests were prescribed by 1798 of the 3052 physicians (58.9%) practising in the Lyon area. Among physicians who prescribed serology, 11.4% of the general practitioners and 10.9% of the specialists prescribed HCV serology tests for the first time during the campaign. Prescriptions for HCV serology increased significantly between the two calendar periods (+15.6%, epsilon = 17.7), similarly for general practitioners and specialists. The number of general practitioners who prescribed more than five serology tests per year increased 15.3% while the number of general practitioners who did not prescribe serology tests decreased 9.7% (P = 0.02). More HCV-positive patients were detected during the campaign (276 patients) than during the previous period (231 patients) [epsilon = 2.8]. CONCLUSION: When provided with pertinent information and training adapted to their medical practice, private practitioners become actively involved in screening for HCV infection.