Decreasing incidence of postcesarean endometritis with extended-spectrum antibiotic prophylaxis.

OBJECTIVE: To describe the effect of an extended-spectrum prophylactic antibiotic regimen on postcesarean endometritis. METHODS: This is a cohort study of trends in postcesarean endometritis using data both from prospective surveillance by the infection control unit and from query of our obstetric computerized database to compare three periods of antibiotic prophylaxis: standard narrow-spectrum with intravenous first- or second-generation cephalosporin (1992-1996), clinical trial of extended-spectrum with addition of intravenous doxycycline and oral azithromycin (1997-1999), and routine use of extended-spectrum with addition of intravenous azithromycin (2001-2006) to standard cephalosporin prophylaxis. RESULTS: A total of 48,913 deliveries at 24 weeks or more of gestation occurred from 1992 to 2006, of which 10,966 (22.4%) were cesarean deliveries. Annual cesarean rates increased from 16% to 27.5%. Trends in the incidence of postcesarean endometritis revealed a biphasic decrease consistent with the phased introduction of extended-spectrum prophylaxis. Incidence (95% confidence interval [CI]) of endometritis by prospective surveillance dropped from 19.9% (95% CI 18.6-21.3%) to 15.4% (95% CI 13.2-17.9%) during the clinical trial period: relative risk (RR) 0.77 (95% CI 0.66-0.91), P=.002; and then to 6.3% (95% CI 5.0-7.9%) during routine use of extended-spectrum prophylaxis: RR 0.41 (95% CI 0.31-0.54), P<.001. Corresponding incidence by database query dropped from 23% (95% CI 21.5-24.4%) to 16% (95% CI 14.4-17.9%): RR 0.69 (95% CI 0.61-0.79), P<.001; and then to 2.1% (95% CI 1.8-2.6%): RR 0.13 (95% CI 0.11-0.16), P<.001. These findings were unchanged after adjusting for potential confounders. CONCLUSION: Extended-spectrum antibiotic prophylaxis involving the addition of azithromycin to standard narrow-spectrum prophylaxis was associated with a significant reduction in postcesarean endometritis. LEVEL OF EVIDENCE: II.

Impact of extended-spectrum antibiotic prophylaxis on incidence of postcesarean surgical wound infection.

OBJECTIVE: We assessed the impact of an extended-spectrum antibiotic prophylaxis regimen (azithromycin in addition to recommended narrow-spectrum cephalosporin) on postcesarean incisional wound infection. STUDY DESIGN: Data from prospective surveillance of surgical site infections at our institution were used to compare incidence in postcesarean incisional wound infection for 3 consecutive time periods of antibiotic prophylaxis: (1) standard (ie, cephalosporin only, 1992-1996); (2) clinical trial of extended spectrum (ie, extended vs cephalosporin only, 1997-1999); and (3) routine use of extended spectrum (2001-2006). RESULTS: The incidence of postcesarean incisional wound infections decreased progressively from 3.1% to 2.4% and then to 1.3% over the 3 consecutive periods (P value for trend < .002). CONCLUSION: Increasing the use of extended-spectrum antibiotic prophylaxis at our institution over 3 time periods was associated with a decreasing trend in postcesarean incisional wound infection.

Dissemination of community-associated methicillin-resistant Staphylococcus aureus in a tertiary care hospital.

BACKGROUND: The epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) was investigated at a tertiary care hospital, and relationship was made between the clinical and genetic definitions of community- and healthcare-associated MRSA. METHODS: Nonduplicate isolates of S. aureus were collected during 2004. Isolates were classified clinically as community-associated (CA) or healthcare-associated (HA). Molecular typing studies were performed on the isolates. RESULTS: Four hundred and two S. aureus isolates were collected, of which 281 (70%) were MRSA. By clinical definition, 58 (21%) were classified as CA-MRSA and 215 (77%) as HA-MRSA. Among CA-MRSA, 36 (62%) harbored a SCCmec type IV gene. None of the SCCmec type IV CA-MRSA expressed inducible clindamycin resistance (MLSBi). Among 57 HA-MRSA isolates, 31 (54.4%) harbored a SCCmec type IV gene; MLSBi present in 5 (16%). Type IV SCCmec MRSA were most often associated with skin and soft tissue infections (RR 3.34 95% CI 1.43, 7.8). USA300 was the most common genotype among both CA- and HA-MRSA. CONCLUSIONS: Community-associated MRSA is a prominent pathogen with its most common genotype, USA300, representing a significant proportion of CA- and HA-MRSA infections in our institution. Clinical definitions of CA- and HA- status do not correlate well with the genetic definitions, particularly for HA-MRSA.

A comparison of 3 metrics to identify health care-associated infections.

BACKGROUND: The best approach to measurement of health care-associated infection rates is controversial. METHODS: We compared 3 metrics to identify catheter-associated bloodstream infection (CA-BSI), catheter-associated urinary tract infection (CA-UTI), and ventilator-associated pneumonia (VAP) in 8 intensive care units during 2009. We evaluated traditional surveillance using National Healthcare Safety Network methodology, data mining with MedMined Data Mining Surveillance (CareFusion Corporation, San Diego, CA), and administrative coding with ICD-9-CM. RESULTS: A total of 65 CA-BSI, 28 CA-UTI, and 48 VAP was identified. Traditional surveillance detected 58 CA-BSI and no false positives; data mining identified 51 cases but 51 false positives; administrative coding documented 6 cases and 6 false positives. Traditional surveillance detected 27 CA-UTI and no false positives; data mining identified 17 cases but 19 false positives; administrative coding documented 3 cases and 1 false-positive. Traditional surveillance detected 41 VAP and no false positives; data mining identified 26 cases but also 79 false positives; administrative coding found 17 cases and 13 false positives. Overall sensitivities were as follows: traditional surveillance, 0.84; data mining, 0.67; administrative coding, 0.18. Positive predictive values were as follows: traditional surveillance, 1.0; data mining, 0.39; administrative coding, 0.57. CONCLUSION: Traditional surveillance proved superior in terms of sensitivity, positive predictive value, and rate estimation.

USA300 genotype community-associated methicillin-resistant Staphylococcus aureus as a cause of surgical site infections.

Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) strains are increasingly recovered from nosocomial settings. We conducted a retrospective study of surgical site infections (SSI) during 2004 and 2005 to determine the prevalence of CA-MRSA; 57% of MRSA strains tested belonged to the USA300 genotype. CA-MRSA has become a prominent cause of SSI at our institution.

Nosocomial spread of Enterococcus faecium resistant to vancomycin and linezolid in a tertiary care medical center.

In May 2004 our institution encountered its first clinical isolate of linezolid-resistant, vancomycin-resistant Enterococcus faecium (LRVRE). Between October 2004 and July 2005, 40 patients from whom LRVRE organisms were recovered in clinical specimens were characterized. Epidemiologic investigation and pulsed-field gel electrophoresis patterns indicated a clonal outbreak related to nosocomial spread.