human
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: We determined the intraoperative serum and wound-muscle concentrations of cefazolin and cefoxitin in 40 patients who were undergoing cholecystectomies . The study employed an open-label design in which all of the patients r and omly received cefazolin sodium ( 20 mg/kg ) or cefoxitin sodium ( 30 mg/kg ) intravenously while the patient was in the ward ( " on call " ) or with the induction of anesthesia . Multiple blood and wound-muscle sample s were collected intraoperatively and assayed for their cephalosporin concentrations . Considerable differences in intraoperative serum and tissue concentrations between antibiotics were apparent ; there were usually higher levels of cefazolin . In all of the patients who received cefazolin sodium , the antimicrobial was detectable in wound tissue at wound closure , while it was detectable in 86 % and 38 % of patients who received cefoxitin sodium with anesthesia and on call , respectively . Because cefoxitin has a much shorter elimination half-life than cefazolin it seems prudent to administer the agent as close to the start of the operation as possible , and readminister the agent every two to three hours until the wound is closed . For cefazolin , on-call administration appears to be acceptable , with readministration not required for at least four hours A prospect i ve , double-blind study comparing a 6 day with a 2 day regimen of cephalothin prophylaxis was conducted among 200 patients undergoing prosthetic valve replacement . No cases of endocarditis occurred during the 2 month follow-up . Sternal wound infection developed in 2.8 per cent of the 6 day group and 2.1 per cent of the 2 day group . Pneumonia developed in 8.5 per cent of the 6 day and 5.3 per cent of the 2 day group ; most of the bacteria isolated were susceptible to cephalothin .  Urinary tract infection developed more frequently in the 2 day group ( 17.0 versus 8.5 per cent ) , particularly during the first 6 postoperative days . Three of 11 patients with no detectable cephalothin in their sera at the close of operation developed staphylococcal wound infections , compared with 2 of 175 patients whose sera contained cephalothin at the close of surgery ( p = 0.002 , Fisher 's exact test ) . A short course of prophylactic antibiotics is prudent , but there is no justification for prolonging their administration Background No data currently exist about use of antibiotics to prevent surgical site infections ( SSI )  among patients undergoing appendectomy in Thail and . We therefore examined risk factors , use , and efficacy of prophylactic antibiotics for surgical site infection SSI among patients with uncomplicated open appendectomy . Methods From July 1 , 2003 to June 30 , 2004 we conducted a prospect i ve cohort study in eight hospitals in Thail and . We used the National Nosocomial Infection Surveillance ( NNIS ) system criteria to identify SSI associated with appendectomy . We used logistic regression analysis to obtain relative risk estimates for predictors of SSI . Results Among 2139 appendectomy patients , we identified 26 SSIs , yielding a SSI rate of 1.2 infections/100 operations . Ninety-two percent of all patients ( 95 % CI , 91.0–93.3 ) received antibiotic prophylaxis . Metronidazole and gentamicin were the two most common antibiotic agents , with a combined single dose administered in 39 % of cases . In 54 % of cases , antibiotic prophylaxis was administered for one day . We found that a prolonged duration of operation was significantly associated with an increased SSI risk . Antibiotic prophylaxis was significantly associated with a decreased risk of SSI regardless of whether the antibiotic was administered preoperatively or intraoperatively . Compared with no antibiotic prophylaxis , SSI relative risks for combined single-dose of metronidazole and gentamicin , one-day prophylaxis , and multiple-day antibiotic prophylaxis were 0.28 ( 0.09–0.90 ) , 0.30 ( 0.11–0.88 ) and 0.32 ( 0.10–0.98 ) , respectively . ConclusionS ingle-dose combination of metronidazole and gentamicin seems sufficient to reduce SSIs in uncomplicated appendicitis patients despite whether the antibiotic was administered preoperatively or intraoperatively OBJECTIVE To quantify surgical-infection rate , to assess adherence with the antibiotic prophylaxis protocol , and to identify independent factors associated with surgical-wound infection ( SWI ) . METHODS We carried out a prospect i ve study of a cohort of 2,237 general surgery patients with postsurgery stays of more than 48 hours .  Odds ratios ( OR ) were estimated using unconditional multiple logistic regression . SETTING A 1,300-bed , university-affiliated , tertiary-care hospital in Madrid , Spain . RESULTS 254 patients developed SWI .  The rate of adherence to the antibiotic prophylaxis protocol  was 63.5 % . Eight factors were independently associated with risk of SWI : age ( OR = 1.2 for every 10 years of age ) ; wound classification ( clean-contaminated , OR = 6.4 ; contaminated , OR = 3.7 ; dirty or infected , OR = 9.3 ) ; antimicrobial prophylaxis ( OR = 0.5 ) ; stay prior to surgery ( OR = 1.1 for every 3 days ) ; duration of operation ( OR = 1.5 for every 60 minutes ) ; malignant neoplasm ( OR = 1.7 ) ; emergency procedure ( OR = 1.99 ) ; intensive-care unit stay prior to surgery ( OR = 2.6 ) ; and antimicrobial prophylaxis administered 2 or more hours before operation ( OR = 5.3 ) . CONCLUSION In general , antimicrobial prophylaxis protects against SWI ( OR = 0.5 ) ; however , administration 2 hours or more before the operation increases the risk of SWI by a factor of 5.3 . Therefore , measures should be taken to ensure the correct timing of antimicrobial prophylaxis BACKGROUND Currently , no single U.S. surveillance system can provide estimates of the burden of all types of health care-associated infections across acute care patient population s. We conducted a prevalence survey in 10 geographically diverse states to determine the prevalence of health care-associated infections in acute care hospitals and generate up date d estimates of the national burden of such infections . METHODS We defined health care-associated infections with the use of National Healthcare Safety Network criteria .  One-day surveys of r and omly selected in patients were performed in participating hospitals . Hospital personnel collected demographic and limited clinical data . Trained data collectors review ed medical records retrospectively to identify health care-associated infections active at the time of the survey . Survey data and 2010 Nationwide Inpatient Sample data , stratified according to patient age and length of hospital stay , were used to estimate the total numbers of health care-associated infections and of in patients with such infections in U.S. acute care hospitals in 2011 . RESULTS Surveys were conducted in 183 hospitals . Of 11,282 patients , 452 had 1 or more health care-associated infections  ( 4.0 % ; 95 % confidence interval , 3.7 to 4.4 ) . Of 504 such infections , the most common types were pneumonia ( 21.8 % ) , surgical-site infections ( 21.8 % ) , and gastrointestinal infections ( 17.1 % ) . Clostridium difficile was the most commonly reported pathogen ( causing 12.1 % of health care-associated infections ) . Device-associated infections ( i.e. , central -catheter-associated bloodstream infection , catheter-associated urinary tract infection , and ventilator-associated pneumonia ) , which have traditionally been the focus of programs to prevent health care-associated infections , accounted for 25.6 % of such infections . We estimated that there were 648,000 patients with 721,800 health care-associated infections in U.S. acute care hospitals in 2011 . CONCLUSIONS Results of this multistate prevalence survey of health care-associated infections indicate that public health surveillance and prevention activities should continue to address C. difficile infections . As device- and procedure-associated infections decrease , consideration should be given to exp and ing surveillance and prevention activities to include other health care-associated infections Background Surgical site infections are the most common hospital-acquired infections among surgical patients . The administration of surgical antimicrobial prophylaxis reduces the risk of surgical site infections . The optimal timing of this procedure is still a matter of debate . While most studies suggest that it should be given as close to the incision time as possible , others conclude that this may be too late for optimal prevention of surgical site infections . A large observational study suggests that surgical antimicrobial prophylaxis should be administered 74 to 30 minutes before surgery . The aim of this article is to report the design and protocol of a r and omized controlled trial investigating the optimal timing of surgical antimicrobial prophylaxis . Methods / Design In this bi-center r and omized controlled trial conducted at two tertiary referral centers in Switzerl and , we plan to include 5,000 patients undergoing general , oncologic , vascular and orthopedic trauma procedures . Patients are r and omized in a 1:1 ratio into two groups : one receiving surgical antimicrobial prophylaxis in the anesthesia room ( 75 to 30 minutes before incision ) and the other receiving surgical antimicrobial prophylaxis in the operating room ( less than 30 minutes before incision ) . We expect a significantly lower rate of surgical site infections with surgical antimicrobial prophylaxis administered more than 30 minutes before the scheduled incision . The primary outcome is the occurrence of surgical site infections during a 30-day follow-up period ( one year with an implant in place ) . When assuming a 5 % surgical site infection risk with administration of surgical antimicrobial prophylaxis in the operating room , the planned sample size has an 80 % power to detect a relative risk reduction for surgical site infections of 33 % when administering surgical antimicrobial prophylaxis in the anesthesia room ( with a two-sided type I error of 5 % ) . We expect the study to be completed within three years . Discussion The results of this r and omized controlled trial will have an important impact on current international guidelines for infection control strategies in the hospital . Moreover , the results of this r and omized controlled trial are of significant interest for patient safety and healthcare economics . Trial registration This trial is registered on Clinical Trials.gov under the identifier NCT01790529 The results of two prospect i ve , r and omized trials , comparing single dose piperacillin with multidose cefoxitin prophylaxis in elective surgical procedures of the gastrointestinal tract were combined to examine some basic aspects of clinical ly , applied antibiotic prophylaxis . As there was no difference in the efficacy of prophylaxis between the groups , data from both centers and both drug groups were combined for analysis . Patients whose ages were greater than 40 years , the presence of cancer and the administration of an antibiotic for longer than 60 minutes preoperatively were associated with a higher rate of infectious complications . Duration of operation was also related to subsequent infection , ranging from 6 per cent in procedures lasting less than two hours to 27 per cent in operations lasting more than four hours . There was a greater failure of prophylaxis in patients undergoing rectal procedures , with a 29 per cent rate of infectious complications compared with 14 per cent in patients undergoing operations upon the colon . This difference was present even when duration of operation was taken into account BACKGROUND Increased incidence of methicillin-resistant Staphylococcus species has required some hospitals to choose vancomycin for surgical prophylaxis . Guidelines for appropriate timing of vancomycin prophylaxis state that the infusion should begin within 120 min before the first surgical incision . However , no studies have investigated the proper timing of vancomycin prophylaxis in relationship to surgical site infections ( SSI ) . The objective of the present study was to assess the effect of vancomycin prophylaxis timing in relation to the first surgical incision on the incidence of SSI . METHODS We prospect ively monitored vancomycin prophylaxis timing and incidence of SSI in 2048 patients undergoing coronary bypass graft or valve replacement surgery . The timing of vancomycin was categorized into five groups based on the relation between the start of the infusion and the surgical cut time . Study hypotheses were tested using logistic analysis and further vali date d using a Heckman two-stage model . RESULTS The incidence of SSI were lowest in the 176 patients given vancomycin between 16 and 60 min before the surgical incision ( 3.4 % ) compared with 15 patients given vancomycin between 0 and 15 min [ 26.7 % ; relative risk ( RR ) : 7.8 ; 95 % CI : 2.5 - 24.7 ] , 888 patients given vancomycin between 61 and 120 min ( 7.7 % ; R 
    Output:
    
agent
Administration of antibiotic prophylaxis more than 120 minutes before incision or after incision is associated a higher risk of surgical site infections than administration less than 120 minutes before incision .
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: We determined the intraoperative serum and wound-muscle concentrations of cefazolin and cefoxitin in 40 patients who were undergoing cholecystectomies . The study employed an open-label design in which all of the patients r and omly received cefazolin sodium ( 20 mg/kg ) or cefoxitin sodium ( 30 mg/kg ) intravenously while the patient was in the ward ( " on call " ) or with the induction of anesthesia . Multiple blood and wound-muscle sample s were collected intraoperatively and assayed for their cephalosporin concentrations . Considerable differences in intraoperative serum and tissue concentrations between antibiotics were apparent ; there were usually higher levels of cefazolin . In all of the patients who received cefazolin sodium , the antimicrobial was detectable in wound tissue at wound closure , while it was detectable in 86 % and 38 % of patients who received cefoxitin sodium with anesthesia and on call , respectively . Because cefoxitin has a much shorter elimination half-life than cefazolin it seems prudent to administer the agent as close to the start of the operation as possible , and readminister the agent every two to three hours until the wound is closed . For cefazolin , on-call administration appears to be acceptable , with readministration not required for at least four hours A prospect i ve , double-blind study comparing a 6 day with a 2 day regimen of cephalothin prophylaxis was conducted among 200 patients undergoing prosthetic valve replacement . No cases of endocarditis occurred during the 2 month follow-up . Sternal wound infection developed in 2.8 per cent of the 6 day group and 2.1 per cent of the 2 day group . Pneumonia developed in 8.5 per cent of the 6 day and 5.3 per cent of the 2 day group ; most of the bacteria isolated were susceptible to cephalothin .  Urinary tract infection developed more frequently in the 2 day group ( 17.0 versus 8.5 per cent ) , particularly during the first 6 postoperative days . Three of 11 patients with no detectable cephalothin in their sera at the close of operation developed staphylococcal wound infections , compared with 2 of 175 patients whose sera contained cephalothin at the close of surgery ( p = 0.002 , Fisher 's exact test ) . A short course of prophylactic antibiotics is prudent , but there is no justification for prolonging their administration Background No data currently exist about use of antibiotics to prevent surgical site infections ( SSI )  among patients undergoing appendectomy in Thail and . We therefore examined risk factors , use , and efficacy of prophylactic antibiotics for surgical site infection SSI among patients with uncomplicated open appendectomy . Methods From July 1 , 2003 to June 30 , 2004 we conducted a prospect i ve cohort study in eight hospitals in Thail and . We used the National Nosocomial Infection Surveillance ( NNIS ) system criteria to identify SSI associated with appendectomy . We used logistic regression analysis to obtain relative risk estimates for predictors of SSI . Results Among 2139 appendectomy patients , we identified 26 SSIs , yielding a SSI rate of 1.2 infections/100 operations . Ninety-two percent of all patients ( 95 % CI , 91.0–93.3 ) received antibiotic prophylaxis . Metronidazole and gentamicin were the two most common antibiotic agents , with a combined single dose administered in 39 % of cases . In 54 % of cases , antibiotic prophylaxis was administered for one day . We found that a prolonged duration of operation was significantly associated with an increased SSI risk . Antibiotic prophylaxis was significantly associated with a decreased risk of SSI regardless of whether the antibiotic was administered preoperatively or intraoperatively . Compared with no antibiotic prophylaxis , SSI relative risks for combined single-dose of metronidazole and gentamicin , one-day prophylaxis , and multiple-day antibiotic prophylaxis were 0.28 ( 0.09–0.90 ) , 0.30 ( 0.11–0.88 ) and 0.32 ( 0.10–0.98 ) , respectively . ConclusionS ingle-dose combination of metronidazole and gentamicin seems sufficient to reduce SSIs in uncomplicated appendicitis patients despite whether the antibiotic was administered preoperatively or intraoperatively OBJECTIVE To quantify surgical-infection rate , to assess adherence with the antibiotic prophylaxis protocol , and to identify independent factors associated with surgical-wound infection ( SWI ) . METHODS We carried out a prospect i ve study of a cohort of 2,237 general surgery patients with postsurgery stays of more than 48 hours .  Odds ratios ( OR ) were estimated using unconditional multiple logistic regression . SETTING A 1,300-bed , university-affiliated , tertiary-care hospital in Madrid , Spain . RESULTS 254 patients developed SWI .  The rate of adherence to the antibiotic prophylaxis protocol  was 63.5 % . Eight factors were independently associated with risk of SWI : age ( OR = 1.2 for every 10 years of age ) ; wound classification ( clean-contaminated , OR = 6.4 ; contaminated , OR = 3.7 ; dirty or infected , OR = 9.3 ) ; antimicrobial prophylaxis ( OR = 0.5 ) ; stay prior to surgery ( OR = 1.1 for every 3 days ) ; duration of operation ( OR = 1.5 for every 60 minutes ) ; malignant neoplasm ( OR = 1.7 ) ; emergency procedure ( OR = 1.99 ) ; intensive-care unit stay prior to surgery ( OR = 2.6 ) ; and antimicrobial prophylaxis administered 2 or more hours before operation ( OR = 5.3 ) . CONCLUSION In general , antimicrobial prophylaxis protects against SWI ( OR = 0.5 ) ; however , administration 2 hours or more before the operation increases the risk of SWI by a factor of 5.3 . Therefore , measures should be taken to ensure the correct timing of antimicrobial prophylaxis BACKGROUND Currently , no single U.S. surveillance system can provide estimates of the burden of all types of health care-associated infections across acute care patient population s. We conducted a prevalence survey in 10 geographically diverse states to determine the prevalence of health care-associated infections in acute care hospitals and generate up date d estimates of the national burden of such infections . METHODS We defined health care-associated infections with the use of National Healthcare Safety Network criteria .  One-day surveys of r and omly selected in patients were performed in participating hospitals . Hospital personnel collected demographic and limited clinical data . Trained data collectors review ed medical records retrospectively to identify health care-associated infections active at the time of the survey . Survey data and 2010 Nationwide Inpatient Sample data , stratified according to patient age and length of hospital stay , were used to estimate the total numbers of health care-associated infections and of in patients with such infections in U.S. acute care hospitals in 2011 . RESULTS Surveys were conducted in 183 hospitals . Of 11,282 patients , 452 had 1 or more health care-associated infections  ( 4.0 % ; 95 % confidence interval , 3.7 to 4.4 ) . Of 504 such infections , the most common types were pneumonia ( 21.8 % ) , surgical-site infections ( 21.8 % ) , and gastrointestinal infections ( 17.1 % ) . Clostridium difficile was the most commonly reported pathogen ( causing 12.1 % of health care-associated infections ) . Device-associated infections ( i.e. , central -catheter-associated bloodstream infection , catheter-associated urinary tract infection , and ventilator-associated pneumonia ) , which have traditionally been the focus of programs to prevent health care-associated infections , accounted for 25.6 % of such infections . We estimated that there were 648,000 patients with 721,800 health care-associated infections in U.S. acute care hospitals in 2011 . CONCLUSIONS Results of this multistate prevalence survey of health care-associated infections indicate that public health surveillance and prevention activities should continue to address C. difficile infections . As device- and procedure-associated infections decrease , consideration should be given to exp and ing surveillance and prevention activities to include other health care-associated infections Background Surgical site infections are the most common hospital-acquired infections among surgical patients . The administration of surgical antimicrobial prophylaxis reduces the risk of surgical site infections . The optimal timing of this procedure is still a matter of debate . While most studies suggest that it should be given as close to the incision time as possible , others conclude that this may be too late for optimal prevention of surgical site infections . A large observational study suggests that surgical antimicrobial prophylaxis should be administered 74 to 30 minutes before surgery . The aim of this article is to report the design and protocol of a r and omized controlled trial investigating the optimal timing of surgical antimicrobial prophylaxis . Methods / Design In this bi-center r and omized controlled trial conducted at two tertiary referral centers in Switzerl and , we plan to include 5,000 patients undergoing general , oncologic , vascular and orthopedic trauma procedures . Patients are r and omized in a 1:1 ratio into two groups : one receiving surgical antimicrobial prophylaxis in the anesthesia room ( 75 to 30 minutes before incision ) and the other receiving surgical antimicrobial prophylaxis in the operating room ( less than 30 minutes before incision ) . We expect a significantly lower rate of surgical site infections with surgical antimicrobial prophylaxis administered more than 30 minutes before the scheduled incision . The primary outcome is the occurrence of surgical site infections during a 30-day follow-up period ( one year with an implant in place ) . When assuming a 5 % surgical site infection risk with administration of surgical antimicrobial prophylaxis in the operating room , the planned sample size has an 80 % power to detect a relative risk reduction for surgical site infections of 33 % when administering surgical antimicrobial prophylaxis in the anesthesia room ( with a two-sided type I error of 5 % ) . We expect the study to be completed within three years . Discussion The results of this r and omized controlled trial will have an important impact on current international guidelines for infection control strategies in the hospital . Moreover , the results of this r and omized controlled trial are of significant interest for patient safety and healthcare economics . Trial registration This trial is registered on Clinical Trials.gov under the identifier NCT01790529 The results of two prospect i ve , r and omized trials , comparing single dose piperacillin with multidose cefoxitin prophylaxis in elective surgical procedures of the gastrointestinal tract were combined to examine some basic aspects of clinical ly , applied antibiotic prophylaxis . As there was no difference in the efficacy of prophylaxis between the groups , data from both centers and both drug groups were combined for analysis . Patients whose ages were greater than 40 years , the presence of cancer and the administration of an antibiotic for longer than 60 minutes preoperatively were associated with a higher rate of infectious complications . Duration of operation was also related to subsequent infection , ranging from 6 per cent in procedures lasting less than two hours to 27 per cent in operations lasting more than four hours . There was a greater failure of prophylaxis in patients undergoing rectal procedures , with a 29 per cent rate of infectious complications compared with 14 per cent in patients undergoing operations upon the colon . This difference was present even when duration of operation was taken into account BACKGROUND Increased incidence of methicillin-resistant Staphylococcus species has required some hospitals to choose vancomycin for surgical prophylaxis . Guidelines for appropriate timing of vancomycin prophylaxis state that the infusion should begin within 120 min before the first surgical incision . However , no studies have investigated the proper timing of vancomycin prophylaxis in relationship to surgical site infections ( SSI ) . The objective of the present study was to assess the effect of vancomycin prophylaxis timing in relation to the first surgical incision on the incidence of SSI . METHODS We prospect ively monitored vancomycin prophylaxis timing and incidence of SSI in 2048 patients undergoing coronary bypass graft or valve replacement surgery . The timing of vancomycin was categorized into five groups based on the relation between the start of the infusion and the surgical cut time . Study hypotheses were tested using logistic analysis and further vali date d using a Heckman two-stage model . RESULTS The incidence of SSI were lowest in the 176 patients given vancomycin between 16 and 60 min before the surgical incision ( 3.4 % ) compared with 15 patients given vancomycin between 0 and 15 min [ 26.7 % ; relative risk ( RR ) : 7.8 ; 95 % CI : 2.5 - 24.7 ] , 888 patients given vancomycin between 61 and 120 min ( 7.7 % ; R 
    Output:
    