Healthcare workers and the incidence of nosocomial infection: can treatment of one influence the other?--a brief review

Nasal carriage by health care workers represents an important hospital reservoir of Staphylococcus aureus. Approximately 25% of all hospital-based healthcare workers are stable nasal carriers. Several studies in the US and UK have shown that following treatment of this group with a single 5-day course of intranasal mupirocin, nasal carriage was usually eradicated within 24 hours, and after 12 weeks was only present in 25% of participants. Long-term follow-up in one institution after 52 weeks showed that there were significantly fewer carriers in the mupirocin group than in the group receiving identical placebo. In the same study, between 30% and 50% of those hospital workers who carried S. aureus in their nose, before the start of therapy, were also hand carriers. After treatment, a dramatic reduction in hand carriage of S. aureus was noted, in contrast to no change in the placebo group. After 6 months, the level of hand carriage was still statistically lower in the mupirocin group than in those given placebo. The association between nasal carriage and hand carriage makes it important that health care workers decontaminate their hands effectively between patients. Current evidence suggests, however, that compliance with such control measures is low. Other studies examining the role of S. aureus nasal carriage in the development of post-operative wound infection, have shown that almost half of those isolates recovered from the wound site were present in the nose of the patient pre-operatively. Due to its ability to eliminate nasal carriage of S. aureus, current studies are investigating whether intranasal mupirocin can prevent post-operative wound infections in patients undergoing surgery.

Long-term efficacy of intranasal mupirocin ointment. A prospective cohort study of Staphylococcus aureus carriage

BACKGROUND

We investigated the long-term effect of a single 5-day application of intranasal mupirocin calcium ointment on Staphylococcus aureus nasal and hand colonization. The subjects were 68 healthy volunteers who were health care workers with stable S aureus nasal carriage and who had participated in a randomized, double-blind placebo-controlled clinical trial of intranasal mupirocin ointment.

METHODS

A 1-year prospective cohort study of S aureus nasal carriers after treatment with active drug or placebo was performed. Cultures were obtained from all subjects 6 and 12 months after therapy. All subjects returned for the 6-month visit; 63 (93%) were examined at 1 year. The major outcome measure was the relative proportion of any S aureus cultured at either site at 6 and 12 months. The S aureus isolates were typed by restriction endonuclease analysis of plasmid DNA and by antibiotic susceptibility tests; the similarity of nasal and hand isolate "fingerprints" was compared.

RESULTS

At 6 months, nasal carriage was 48% in the treatment group vs 72% in controls (relative risk, 0.68; 95% confidence interval, 0.45 to 1.02; P = .054); at 1 year, nasal carriage was 53% vs 76%, respectively (relative risk, 0.70; 95% confidence interval, 0.48 to 1.02; P = .056). Hand carriage at 6 months was significantly reduced among mupirocin recipients relative to controls (15% and 48%; P = .04, adjusted for the baseline rate of hand carriage). Thirty-six percent of treated subjects were recolonized in the nares with a new strain at 1 year, whereas 34% had reisolation of the original strain after initially negative posttherapy cultures. During the year of follow-up, hand carriage was observed at least once in two thirds of the subjects. Nearly all of the hand isolates (87%) exactly matched the subjects' coincident nasal plasmid fingerprint and antibiogram type.

CONCLUSIONS

A single brief treatment course of intranasal mupirocin was effective in reducing nasal S aureus carriage for up to 1 year. When S aureus was recovered after nasal decolonization, the new isolate was as likely to represent colonization with a new strain as reisolation of the original strain. Staphylococcus aureus hand carriage was significantly decreased 6 months after therapy, further implicating the nares as the primary reservoir site for hand carriage.

An experimental model for study of Candida survival and transmission in human volunteers

In order to determine the potential for cross-transmission of Candida spp. between health-care workers and patients, the survival of clinical isolates of five species of Candida on the palms of human volunteers was tested. One hundred microliters of a McFarland 1.0 density suspension (5 x 10(5) cfu) from an overnight culture of Candida albicans, Candida krusei, Candida parapsilosis, Candida tropicalis and Candida glabrata was used as inoculum. The degree of hydrophobicity of the different Candida species was also tested and did not influence the survival. The half-lives were brief, being 9.5, 12.4, 7.4, 12.8, 9.6 min for Candida albicans, Candida krusei, Candida glabrata, Candida parapsilosis, and Candida tropicalis, respectively, but at 45 min 2.6 x 10(3) to 3 x 10(4) organisms remained on the hands. Survival of Candida albicans for as long as 24 h on inanimate surfaces was observed. Transmission from one hand to a second hand occurred in 69% of the experiments and from the first to a third hand in 38%. Transmission to and from inanimate surfaces was successful in most of the experiments (90%). This experimental model aids in the biological study of Candida spp. and suggests some of the potential mechanisms of transmission.

Nosocomial bloodstream infection in critically ill patients. Excess length of stay, extra costs, and attributable mortality

OBJECTIVE

To determine the excess length of stay, extra costs, and mortality attributable to nosocomial bloodstream infection in critically ill patients.

DESIGN

Pairwise-matched (1:1) case-control study.

SETTING

Surgical intensive care unit (SICU) in a tertiary health care institution.

PATIENTS

All patients admitted in the SICU between July 1, 1988, and June 30, 1990, were eligible. Cases were defined as patients with nosocomial bloodstream infection; controls were selected according to matching variables in a stepwise fashion.

METHODS

Matching variables were primary diagnosis for admission, age, sex, length of stay before the day of infection in cases, and total number of discharge diagnoses. Matching was successful for 89% of the cohort; 86 matched case-control pairs were studied.

MAIN OUTCOME MEASURES

Crude and attributable mortality, excess length of hospital and SICU stay, and overall costs.

RESULTS

Nosocomial bloodstream infection complicated 2.67 per 100 admissions to the SICU during the study period. The crude mortality rates from cases and controls were 50% and 15%, respectively (P < .01); thus, the estimated attributable mortality rate was 35% (95% confidence interval, 25% to 45%). The median length of hospital stay significantly differed between cases and controls (40 vs 26 days, respectively; P < .01). When only matched pairs who survived bloodstream infection were considered (n = 41), cases stayed in the hospital a median of 54 days vs 30 days for controls (P < .01), and cases stayed in the SICU a median of 15 days vs 7 days for controls (P < .01). Thus, extra hospital and SICU length of stay attributable to bloodstream infection was 24 and 8 days, respectively. Extra costs attributable to the infection averaged $40,000 per survivor.

CONCLUSIONS

The attributable mortality from nosocomial bloodstream infection is high in critically ill patients. The infection is associated with a doubling of the SICU stay, an excess length of hospital stay of 24 days in survivors, and a significant economic burden.

Nosocomial bloodstream infection in critically ill patients. Excess length of stay, extra costs, and attributable mortality

OBJECTIVE

To determine the excess length of stay, extra costs, and mortality attributable to nosocomial bloodstream infection in critically ill patients.

DESIGN

Pairwise-matched (1:1) case-control study.

SETTING

Surgical intensive care unit (SICU) in a tertiary health care institution.

PATIENTS

All patients admitted in the SICU between July 1, 1988, and June 30, 1990, were eligible. Cases were defined as patients with nosocomial bloodstream infection; controls were selected according to matching variables in a stepwise fashion.

METHODS

Matching variables were primary diagnosis for admission, age, sex, length of stay before the day of infection in cases, and total number of discharge diagnoses. Matching was successful for 89% of the cohort; 86 matched case-control pairs were studied.

MAIN OUTCOME MEASURES

Crude and attributable mortality, excess length of hospital and SICU stay, and overall costs.

RESULTS

Nosocomial bloodstream infection complicated 2.67 per 100 admissions to the SICU during the study period. The crude mortality rates from cases and controls were 50% and 15%, respectively (P < .01); thus, the estimated attributable mortality rate was 35% (95% confidence interval, 25% to 45%). The median length of hospital stay significantly differed between cases and controls (40 vs 26 days, respectively; P < .01). When only matched pairs who survived bloodstream infection were considered (n = 41), cases stayed in the hospital a median of 54 days vs 30 days for controls (P < .01), and cases stayed in the SICU a median of 15 days vs 7 days for controls (P < .01). Thus, extra hospital and SICU length of stay attributable to bloodstream infection was 24 and 8 days, respectively. Extra costs attributable to the infection averaged $40,000 per survivor.

CONCLUSIONS

The attributable mortality from nosocomial bloodstream infection is high in critically ill patients. The infection is associated with a doubling of the SICU stay, an excess length of hospital stay of 24 days in survivors, and a significant economic burden.

Investigation of the sequence of colonization and candidemia in nonneutropenic patients

Among neutropenic patients with hematologic malignancies, candidemia has been shown to arise typically from autoinfection after colonization. In patients without neutropenia, we examined the similarities of strains colonizing or infecting various body sites and those subsequently causing Candida bloodstream infections. Strain similarity was examined by karyotyping and restriction endonuclease analysis of genomic DNA (REAG) by using two restriction enzymes (SfiI and BssHII). The banding patterns of 42 isolates from 19 patients were independently evaluated in a blinded fashion by three observers. The interobserver reliability measured with a generalized kappa statistic was 0.59 for karyotyping, 0.84 for REAG with SfiI, and 0.88 for REAG with BssHII (P < 0.001 for each). REAG classified the initial colonizing or infecting isolate and subsequent blood isolates as identical in 16 patients (84%). The mean duration of colonization or infection prior to a positive blood culture was 5 and 23 days in patients infected with related and unrelated isolates, respectively (P = 0.14; 95% confidence interval = -14.5 to 50.5). Karyotyping results matched the REAG results for isolates from 14 of the 19 patients (74%). In patients infected with identical isolates, the initial isolate was most frequently recovered from the urine (n = 5) or vascular catheter tips (n = 4). In the five subjects with organisms showing disparate results between the methods, karyotyping revealed different banding patterns, whereas REAG suggested that the isolates were identical. Candida colonization or infection with an identical strain frequently precedes bloodstream infection in nonneutropenic patients. Future studies should evaluate whether patients at high risk for candidemia and who have vascular catheter or urine samples that are positive for a Candida on culture should be treated empirically.

Quality standard for assurance of measles immunity among health care workers. Infectious Diseases Society of America

OBJECTIVE

The objective of this quality standard is to prevent nosocomial transmission of measles by assuring universal measles-mumps-rubella (MMR) vaccination of all health care workers who lack immunity to measles. Although the primary emphasis is on health care workers in hospitals, those at other sites, such as clinics, nursing homes, and schools, are also included. It will be the responsibility of designated individuals at these institutions to implement the standard.

OPTIONS

We considered advocating the use of measles vaccine rather than MMR vaccine but chose the latter because it also protects against mumps and rubella and because it is more readily available.

OUTCOMES

The desired outcome is a reduction in the nosocomial transmission of measles.

EVIDENCE

Although direct comparative studies are lacking, nosocomial outbreaks of measles have been reported (as recently as 1992) in institutions where measles immunization of nonimmune health care workers is not universal, whereas such outbreaks have not been reported in institutions with universal immunization. VALUES AND VALIDATION: We consulted more than 50 infectious-disease experts from the fields of epidemiology, government, medicine, nursing, obstetrics and gynecology, pediatrics, and surgery. In light of disagreement regarding the implementation of the standard, we used group discussions to reach a consensus.

BENEFITS, HARMS, AND COSTS

The consequences of the transmission of measles (and of mumps and rubella) in a health care institution include not only the morbidity and mortality attributable to the disease but also the significant cost of evaluating and containing an outbreak and the serious disruption of regular hospital routines when control measures are instituted. The potential harm to health care workers after the implementation of the standard consists of untoward effects of MMR vaccine, although the reactions of vaccinees should be minimal with adherence to recommended vaccination procedures. Implementation of the standard should entail no expense to health care workers; the precise cost to institutions is unknown, but the expense would be mitigated by the prevention of measles outbreaks.

RECOMMENDATIONS

We recommend MMR vaccination of all health care workers who lack immunity to measles.

SPONSORS

The Quality Standards Subcommittee of the Clinical Affairs Committee of the Infectious Diseases Society of America (IDSA) developed the standard. The subcommittee was composed of representatives of the IDSA (P.A.G. and J.E.M.), the Society for Hospital Epidemiology of America (R.P.W.), the Surgical Infection Society (E.P.D.), the Pediatric Infectious Diseases Society (P.J.K.), the Centers for Disease Control and Prevention (W.J.M.), the Obstetrics and Gynecology Infectious Diseases Society (R.L.S.), and the Association of Practitioners of Infection Control (T.L.B.). Funding was provided by the IDSA and the other cooperating organizations. The standard is endorsed by the IDSA.

Quality standard for the treatment of bacteremia. The Infectious Diseases Society of America

OBJECTIVE

The objective of this quality standard is to optimize the treatment of bacteremia in hospitalized patients by ensuring that the antibiotic given is appropriate in terms of the blood culture susceptibility of the pathogen. Although this standard may appear to be minimal in scope, it is needed because appropriate antimicrobial treatment is not given in 5% to 17% of cases. To implement the standard, physicians, pharmacists, and microbiologists will need to devise a coordinated strategy.

OPTIONS

We considered criteria for appropriate dosing, most cost-effective selection, proper antibiotic levels in serum, least toxicity, narrowest spectrum, specific clinical indications, and optimal duration of treatment. All these criteria were rejected as the basis for the standard because they were too controversial and too difficult to be applied by a nonphysician chart reviewer. In contrast, the selection of an antibiotic to which the pathogen is sensitive is a noncontroversial criterion and easy for a chart reviewer to apply.

OUTCOMES

The standard is designed to reduce the incidence of adverse outcomes of septicemia such as renal failure, prolonged hospitalization, and death.

EVIDENCE

Several well-designed clinical trials without randomization as well as case-controlled studies have confirmed the benefit of using an antibiotic that is appropriate in light of the susceptibility of the isolate in blood culture. Prospective, randomized, placebo-controlled trials are not available.

VALUES

Our premise is that the presence of bacteremia is a risk factor for serious adverse outcomes. We also believe that the administration of antibiotics must always be guided by the susceptibility report for the pathogen(s) obtained from blood cultures. This concern is more critical for pathogens from the blood than for those from most other body sites. We had evidence that susceptibility reports for pathogens from positive blood cultures were not always used properly. We used group discussion to reach a consensus among the members of the Quality Standards Subcommittee.

BENEFITS, HARMS, AND COSTS

Through the implementation of this standard, at least 5% of bacteremias could be treated more appropriately. An unknown number of deaths would likely be prevented, and mortality from bacteremia treated inappropriately would probably be reduced. The primary undesirable feature of the standard is an increased workload of pharmacists and microbiologists.

RECOMMENDATIONS

Treatment of bacteremia with an antibiotic that is appropriate in terms of the pathogen's blood-culture susceptibility is a minimal standard of care for all patients.

VALIDATION

We consulted more than 50 experts in infectious diseases from the fields of medicine, surgery, pediatrics, obstetrics and gynecology, nursing, epidemiology, pharmacology, and government. In addition, the methods for its implementation were reviewed by the American Society of Hospital Pharmacists and were tested by one of the members of the Quality Standards Subcommittee.

SPONSORS

The Quality Standards Subcommittee of the Clinical Affairs Committee of the Infectious Diseases Society of America (IDSA) developed the standard. The subcommittee was composed of representatives of the IDSA (Drs. Gross and McGowan), the Society for Hospital Epidemiology of America (Dr. Wenzel), the Surgical Infection Society (Dr. Dellinger), the Pediatric Infectious Diseases Society (Dr. Krause), the Centers for Disease Control and Prevention (Dr. Martone), the Obstetrics and Gynecology Infectious Diseases Society (Dr. Sweet), and the Association of Practitioners of Infection Control (Ms. Barrett). Funding was provided by the IDSA and the other cooperating organizations. This standard is endorsed by the IDSA.

Quality standard for assurance of measles immunity among health care workers. The Infectious Diseases Society of America

OBJECTIVE

The objective of this quality standard is to prevent nosocomial transmission of measles by assuring universal measles-mumps-rubella (MMR) vaccination of all health care workers who lack immunity to measles. Although the primary emphasis is on health care workers in hospitals, those at other sites, such as clinics, nursing homes, and schools, are also included. It will be the responsibility of designated individuals at these institutions to implement the standard.

OPTIONS

We considered advocating the use of measles vaccine rather than MMR but chose the latter because it also protects against mumps and rubella and because it is more readily available.

OUTCOMES

The desired outcome is a reduction in the nosocomial transmission of measles.

EVIDENCE

Although direct comparative studies are lacking, nosocomial outbreaks of measles have been reported (as recently as 1992) in institutions where measles immunization of nonimmune health care workers is not universal, whereas such outbreaks have not been reported in institutions with universal immunization. VALUES AND VALIDATION: We consulted more than 50 infectious-disease experts in epidemiology, government, medicine, nursing, obstetrics and gynecology, pediatrics, and surgery. In light of disagreement regarding the implementation of the standard, we used group discussions to reach a consensus.

BENEFITS, HARMS, AND COSTS

The consequences of the transmission of measles (and of mumps and rubella) in a health care institution include not only the morbidity and mortality attributable to the disease, but also the significant cost of evaluating and containing an outbreak and the serious disruption of regular hospital routines when control measures are instituted. The potential harm to health care workers after the implementation of the standard consists of untoward effects of MMR vaccine, although the reactions of vaccines should be minimal with adherence to recommended vaccination procedures. Implementation of the standard should entail no expense to health care workers; the precise cost to institutions is unknown, but the expense would be mitigated by prevention of measles outbreaks.

RECOMMENDATIONS

We recommend MMR vaccination of all health care workers who lack immunity to measles.

SPONSORS

The Quality Standards Subcommittee of the Clinical Affairs Committee of the Infectious Diseases Society of America (IDSA) developed the standard. The subcommittee was composed of representatives of the IDSA (Drs. Gross and McGowan), the Society for Hospital Epidemiology of America (Dr. Wenzel), the Surgical Infection Society (Dr. Dellinger), the Pediatric Infectious Diseases Society (Dr. Krause), the Centers for Disease Control and Prevention (Dr. Martone), the Obstetrics and Gynecology Infectious Diseases Society (Dr. Sweet), and the Association of Practitioners of Infection Control (Ms. Barrett). Funding was provided by the IDSA and the other cooperating organizations. The standard is endorsed by the IDSA.

Quality standard for the treatment of bacteremia. Infectious Diseases Society of America

OBJECTIVE

The objective of this quality standard is to optimize the treatment of bacteremia in hospitalized patients by ensuring that the antibiotic given is appropriate in terms of the blood culture susceptibility of the pathogen. Although this standard may appear to be minimal in scope, it is needed because appropriate antimicrobial treatment is not given in 5%-17% of cases. To implement the standard, physicians, pharmacists, and microbiologists will need to devise a coordinated strategy.

OPTIONS

We considered criteria for appropriate dosing, most cost-effective selection, proper antibiotic levels in serum, least toxicity, narrowest spectrum, specific clinical indications, and optimal duration of treatment. All these criteria were rejected as the basis for the standard because they were too controversial and too difficult to be applied by a nonphysician chart reviewer. In contrast, the selection of an antibiotic to which the pathogen is sensitive is a noncontroversial criterion that is easy for a chart reviewer to apply.

OUTCOMES

The standard is designed to reduce the incidence of adverse outcomes of septicemia, such as renal failure, prolonged hospitalization, and death.

EVIDENCE

Several well-designed clinical trials without randomization as well as case-controlled studies have confirmed the benefit of using an antibiotic that is appropriate in light of the susceptibility of the isolate in blood culture. Prospective, randomized, placebo-controlled trials are not available.

VALUES

Our premise is that the presence of bacteremia is a risk factor for serious adverse outcomes. We also believe that the administration of antibiotics must always be guided by the susceptibility report for the pathogen(s) obtained from blood cultures. This concern is more critical for pathogens from the blood than for those from most other body sites. We had evidence that susceptibility reports for pathogens from positive blood cultures were not always used properly. We used group discussion to reach a consensus among the members of the Quality Standards Subcommittee.

BENEFITS, HARMS, AND COSTS

Through the implementation of this standard, at least 5% of cases of bacteremia could be treated more appropriately. An unknown number of deaths would likely be prevented, and mortality from bacteremia treated inappropriately would probably be reduced. The primary undesirable feature of the standard is an increased workload for pharmacists and microbiologists.

RECOMMENDATIONS

Treatment of bacteremia with an antibiotic that is appropriate in terms of the pathogen's blood-culture susceptibility is a minimal standard of care for all patients.

VALIDATION

We consulted more than 50 experts in infectious diseases from the fields of medicine, surgery, pediatrics, obstetrics and gynecology, nursing, epidemiology, pharmacology, and government. In addition, the methods for its implementation were reviewed by the American Society of Hospital Pharmacists and were tested by one of the members of the Quality Standards Subcommittee.

SPONSORS

The Quality Standards Subcommittee of the Clinical Affairs Committee of the Infectious Diseases Society of America (IDSA) developed the standard. The subcommittee was composed of representatives of the IDSA (P.A.G. and J.E.M.), the Society for Hospital Epidemiology of America (R.P.W.), the Surgical Infection Society (E.P.D.), the Pediatric Infectious Diseases Society (P.J.K.), the Centers for Disease Control and Prevention (W.J.M.), the Obstetrics and Gynecology Infectious Diseases Society (R.L.S.), and the Association of Practitioners of Infection Control (T.L.B.). Funding was provided by the IDSA and the other cooperating organizations. The standard is endorsed by the IDSA.

Quality standard for antimicrobial prophylaxis in surgical procedures. The Infectious Diseases Society of America

OBJECTIVE

The objectives of this quality standard are 1) to provide an implementation mechanism that will facilitate the reliable administration of prophylactic antimicrobial agents to patients undergoing operative procedures in which such a practice is judged to be beneficial and 2) to provide a guideline that will help local hospital committees formulate policies and set up mechanisms for their implementation. Although standards in the medical literature spell out recommendations for specific procedures, agents, schedules, and doses, other reports document that these standards frequently are not followed in practice.

OPTIONS

We have specified the procedures in which the administration of prophylactic antimicrobial agents has been shown to be beneficial, those in which this practice is widely thought to be beneficial but in which compelling evidence is lacking, and those in which this practice is controversial. We have examined the evidence regarding the optimal timing of drug administration, the optimal dose, and the optimal duration of prophylaxis.

OUTCOMES

The intended outcome is more uniform and reliable administration of prophylactic antibiotics in those circumstances where their value has been demonstrated or their use has been judged by the local practicing medical community to be desirable. The result should be a reduction in rates of postoperative wound infection with a limitation on the quantities of antimicrobial agents used in circumstances where they are not likely to help.

EVIDENCE

Many prospective, randomized, controlled trials comparing placebo with antibiotic and comparing one antibiotic with another have been conducted. In addition, some trials have compared the efficacy of different doses or methods of administration. Other papers have reported on the apparent efficacy of administration at different times and on actual practice in specific communities. Only a small group of relevant articles found through 1993 are cited herein. When authoritative reviews are available, these--rather than an exhaustive list of original references--are cited.

VALUES

We assumed that reducing rates of postoperative infection was valuable but that reducing the total amount of antimicrobial agents employed was also worthwhile. The cost of and morbidity attributable to postoperative wound infections should be weighed against the cost and potential morbidity associated with excessive use of antimicrobial agents.

BENEFITS, HARMS, AND COSTS

More reliable administration of antimicrobial agents according to recognized guidelines should prevent some postoperative wound infections while lowering the total quantity of these drugs used. No harms are anticipated. The costs involved are those of the efforts needed on a local basis to design and implement the mechanism that supports uniform and reliable administration of prophylactic antibiotics.

RECOMMENDATIONS

All patients for whom prophylactic antimicrobial agents are recommended should receive them. The agents given should be appropriate in light of published guidelines. A short duration of prophylaxis (usually < 24 hours) is recommended.

VALIDATION

More than 50 experts in infectious disease and 10 experts in surgical infectious disease and surgical subspecialties reviewed the standard. In addition, the methods for its implementation were reviewed by the American Society of Hospital Pharmacists.

SPONSORS

The Quality Standards Subcommittee of the Clinical Affairs Committee of the Infectious Disease Society of America (IDSA) developed the standard. The subcommittee was composed of representatives of the IDSA (Drs. Gross and McGowan), the Society for Hospital Epidemiology of America (Dr. Wenzel), the Surgical Infection Society (Dr. Dellinger), the Pediatric Infectious Disease Society (Dr. Krause), the Centers for Disease Control and Prevention (Dr. Martone), the Obstetrics and Gynecology Infectious Diseases Society (Dr. Sweet), and the Association of Practitioners of Infection Contr

Quality standard for antimicrobial prophylaxis in surgical procedures. Infectious Diseases Society of America

OBJECTIVE

The objectives of this quality standard are (1) to provide an implementation mechanism that will facilitate the reliable administration of prophylactic antimicrobial agents to patients undergoing operative procedures in which such a practice is judged to be beneficial and (2) to provide a guideline that will help local hospital committees formulate policies and set up mechanisms for their implementation. Although standards in the medical literature spell out recommendations for specific procedures, agents, schedules, and doses, other reports document that these standards frequently are not followed in practice.

OPTIONS

We have specified the procedures in which the administration of prophylactic antimicrobial agents has been shown to be beneficial, those in which this practice is widely thought to be beneficial but in which compelling evidence is lacking, and those in which this practice is controversial. We have examined the evidence regarding the optimal timing of drug administration, the optimal dose, and the optimal duration of prophylaxis.

OUTCOMES

The intended outcome is more uniform and reliable administration of prophylactic antibiotics in those circumstances where their value has been demonstrated or their use has been judged by the local practicing medical community to be desirable. The result should be a reduction in rates of postoperative wound infection in conjunction with a limitation on the quantities of antimicrobial agents used in circumstances where they are not likely to help.

EVIDENCE

Many prospective, randomized, controlled trials comparing placebo with antibiotic and comparing one antibiotic with another have been conducted. In addition, some trials have compared the efficacy of different doses or methods of administration. Other papers have reported on the apparent efficacy of administration at different times and on actual practice in specific communities. Only a small group of relevant articles found through 1993 are cited herein. When authoritative reviews are available, these--rather than an exhaustive list of original references--are cited.

VALUES

We assumed that reducing rates of postoperative infection was valuable but that reducing the total amount of antimicrobial agents employed was also worthwhile. The cost of and morbidity attributable to postoperative wound infections should be weighted against the cost and potential morbidity associated with excessive use of antimicrobial agents.

BENEFITS, HARMS, AND COSTS

More reliable administration of antimicrobial agents according to recognized guidelines should prevent some postoperative wound infections while lowering the total quantity of these drugs used. No harms are anticipated. The costs involved are those of the efforts needed on a local basis to design and implement the mechanism that supports uniform and reliable administration of prophylactic antibiotics.

RECOMMENDATIONS

All patients for whom prophylactic antimicrobial agents are recommended should receive them. The agents given should be appropriate in light of published guidelines. A short duration of prophylaxis (usually < 24 hours) is recommended.

VALIDATION

More than 50 experts in infectious diseases and 10 experts in surgical infectious diseases and surgical subspecialties reviewed the standard. In addition, the methods for its implementation were reviewed by the American Society of Hospital Pharmacists.

SPONSORS

The Quality Standards Subcommittee of the Clinical Affairs Committee of the Infectious Diseases Society of America (IDSA) developed the standard. The subcommittee was composed of representatives of the IDSA (P.A.G. and J.E.M.), the Society for Hospital Epidemiology of America (R.P.W.), the Surgical Infection Society (E.P.D.), the Pediatric Infectious Diseases Society (P.J.K.), the Centers for Disease Control and Prevention (W.J.M.), the Obstetrics and Gynecology Infectious Diseases Society (R.L.S.), and the Association of Practitioners of Infection Control (T.

Comparative analysis of three antifungal susceptibility test methods against prospectively collected Candida species

We performed antifungal susceptibility tests with cilofungin (LY121019), amphotericin B, and flucytosine against 38 strains of yeasts from patients with esophagitis or fungemia either before, during, or after treatment with cilofungin. Tests were performed using a macrobroth dilution method similar to that proposed by the National Committee for Clinical Laboratory Standards (M27-P) and two microbroth methods. For cilofungin and amphotericin B, minimum inhibitory concentrations from microbroth tests using Antibiotic Medium 3 (AM3) were systematically lower than results from the other two methods that utilized RPMI-1640 medium (RPMI). AM3 did not provide any greater degree of in vitro correlation with clinical results than did RPMI. We conclude that cilofungin and possibly other congeners of the echinocandin class of antifungal agents can effectively be studied using the proposed National Committee for Clinical Laboratory Standards method.

An outbreak of hepatitis A among health care workers: risk factors for transmission

OBJECTIVES

The purpose of this study was to investigate a nosocomial outbreak of hepatitis A that occurred in the burn treatment center of a referral hospital.

METHODS

Retrospective cohort and case-control studies were performed to determine acquisition rates and risk factors for transmission. Adjusted infection rates were calculated by week of exposure. A case-control study was conducted to determine potential mechanisms for nosocomial acquisition. Recently infected health care workers were defined as case patients; exposed, serosusceptible health care workers without infection served as controls.

RESULTS

The outbreak of hepatitis A affected 11 health care workers and 1 other burn patient (1 secondary patient case). All 11 health care workers became ill after the admission of a man and his 8-month-old son who developed hepatitis A while in the hospital. The cumulative incidence risk ratio was elevated for health care workers caring for either the infant or the father during the same week of exposure. The case-control study implicated the behavior of eating on the hospital ward as the single most important risk factor for infection.

CONCLUSION

Inadequate hand-washing and subsequent oral contamination appear responsible for the outbreak. Hospitals may witness other institutional outbreaks if health care workers regularly eat on the wards.

Association of secondary and polymicrobial nosocomial bloodstream infections with higher mortality

The objective of this study was to characterize microbiological factors independently associated with higher mortality rates following nosocomial bloodstream infection. All patients admitted to the University of Iowa Hospitals and Clinics between 1 July 1989 and 30 June 1990 who developed a nosocomial bloodstream infection were included. The crude in-house mortality for the 364 patients with nosocomial bloodstream infections was 33%. These deaths accounted for 25% of all in-hospital deaths. Significant risk factors for death from bloodstream infection included diagnoses of cancers and diseases of the cardiovascular and respiratory systems (p < 0.01). Neither previous surgery nor neutropenia was associated with higher mortality rates. Whereas the crude mortality rates associated with gram-negative (33%) and gram-positive (31%) bloodstream infections were similar, that associated with fungemia was higher (54%, p < 0.02). The mortality associated with secondary bloodstream infections (46%) was higher than that associated with primary bloodstream infections (28%, p < 0.001). Furthermore, polymicrobial infections had a worse prognosis than infections from which a single pathogen was isolated (p < 0.05). A multivariate, logistic regression model identified four variables that independently predicted mortality (p = 0.025): age (OR 1.01 per year; CI95 1.00-1.02); cancer (OR 2.35, CI95 1.26-4.37) or diseases of the cardiovascular or respiratory systems (OR 2.20, CI95 1.04-4.67); polymicrobial infection (OR 2.34; CI95 1.21-4.53); and secondary bloodstream infection (OR 2.46; CI95 1.50-4.02). The last variable was the strongest independent predictor. Our study demonstrates the importance of microbiological factors in the outcome of nosocomial bloodstream infections.

Tumor necrosis factor and the therapeutic potential of anti-tumor necrosis factor antibodies

OBJECTIVE

To review the relationship of tumor necrosis factor (TNF) to clinical sepsis and the clinical potential of anti-TNF therapy in decreasing morbidity and mortality rates due to sepsis.

DATA SOURCES

The international English language literature was reviewed, including animal studies and human clinical trials regarding TNF, anticytokine therapy, and sepsis.

STUDY SELECTION

Studies which characterized the immunopharmacologic interactions between TNF and sepsis were emphasized.

DATA EXTRACTION

This study specifically focused on experiments and clinical trials that directly involve the activity of TNF or anti-TNF antibodies, particularly but not limited to data derived from septic patients.

DATA SYNTHESIS

The relationship between TNF and sepsis is described. Clinical aspects of anti-TNF therapy (timing, empiric use) are discussed. Phase I, II, and III trail of anti-TNF antibodies in clinical trials are reviewed.

CONCLUSIONS

Current clinical strategies for sepsis therapy are only partially effective. Recent immunopharmacologic advancements have resulted in the identification of TNF as a pivotal proinflammatory cytokine mediator of sepsis. Animal studies demonstrate that anti-TNF therapy protects animals from the morbidity and mortality of sepsis. Phase I clinical studies of anti-TNF antibodies demonstrate the safety of monoclonal antibody therapy. The therapeutic application of anti-TNF antibodies in sepsis trials is ongoing.

Postoperative wound infection after total abdominal hysterectomy: a controlled study of the increased duration of hospital stay and trends in postoperative wound infection

BACKGROUND

Total abdominal hysterectomy, a common operative procedure, is infrequently accompanied by incisional wound infection. No recent study has examined the excess hospital stay attributable to such infections.

METHODS

This historical cohort study of cases and matched controls was performed in a tertiary care university hospital.

RESULTS

During the 5-year study period (1985 to 1989), the infection rate was 10.5 per 100 procedures; patients with infection remained hospitalized 3.55 days longer than did matched control patients (p = 0.0025).

CONCLUSION

In this era after the introduction of the diagnosis-related groups for reimbursement, incisional wound infection after total abdominal hysterectomy leads to a significant period of extra hospital stay.

Secular trends in rates and etiology of nosocomial urinary tract infections at a university hospital

To examine changing trends in the microbial etiology of nosocomial urinary tract infections, we reviewed culture data from a surveillance database for the calendar years 1982 to 1991. The overall rates of nosocomial urinary tract infections have increased significantly during the last decade from 2.63 per 1,000 patient-days to 4.35 per 1,000 patient-days (p = 0.0023). For specific isolates the rates of yeasts, Klebsiella pneumoniae and group B streptococcus have increased significantly during the last decade. The rates of Escherichia coli, Proteus species and Pseudomonas species have all decreased. Analysis of these secular trends can provide important information relating to the etiology of nosocomial urinary tract infections. It is likely that antibiotic "pressure" has influenced the microbiology of infections and that altered case-mix would explain much of the increase in rates. However, the multiple reasons for these secular trends and their precise contributions to them are unknown.

Trends in antimicrobial utilization at a tertiary teaching hospital during a 15-year period (1978-1992)

BACKGROUND

Antimicrobials are a major part of hospital pharmacy budgets and must be considered in resource planning and spending projections. Logically, trends in antimicrobial usage should be linked to trends in resistant pathogens.

OBJECTIVE

To examine long-term trends in antimicrobial use over a 15-year period (1978 to 1992) and contrast them with changes in pathogens causing nosocomial bacteremia.

SETTING

A 900-bed, tertiary care teaching hospital.

METHODS

Pharmacy records were reviewed to identify parenteral antimicrobial agents administered to adult inpatients. Results were expressed in average daily adult doses per 1,000 patient days.

RESULTS

Chloramphenicol use decreased, while use of penicillin G, antistaphylococcal penicillins, first-generation cephalosporins, and aminoglycosides remained relatively stable. In contrast, there was a sharp increase in the use of second- and third-generation cephalosporins (7-fold and 6.5-fold increase, respectively), vancomycin (161-fold increase), metronidazole (32-fold increase) and amphotericin B (35-fold increase). The proportion of nosocomial bacteremias due to methicillin-resistant gram-positive bacteria rose, but gentamicin resistance in gram-negatives remained at low levels. During the past 14 years, the percentage of patients receiving at least one parenteral antimicrobial rose from 23% to 44%. Among patients receiving antimicrobials, the average number of different agents used per patient increased from 1.8 to 2.1.

CONCLUSIONS

If newer agents were available, use of older agents usually declined. If newer alternatives were not available, use of older agents rose sharply. The increased use of antimicrobials in adults was related to the expanded proportion of patients receiving these agents.

Importance of pre-existing co-morbidities for prognosis of septicemia in critically ill patients

OBJECTIVE

To determine admission characteristics associated with the outcome of septicemia in critically ill patients and more specifically assess the prognostic value of pre-existing co-morbidities.

DESIGN

5 year-retrospective cohort study.

SETTING

Surgical Intensive Care Unit (ICU-20 beds) in a 1600 bed-tertiary care center.

PATIENTS

Among 5457 patients admitted to the ICU between 1984 and 1988, 176 (3.2%) met prospectively-defined criteria for blood culture-proven septicemia (8.77 per 1000 patient-days). Overall septicemic patients had a 5-fold increased risk of death compared to non-septicemic patients (relative risk 5.03, 95% confidence intervals 4.17-6.07, p < 0.0001), and this estimate persisted after stratification according to age, sex, primary diagnosis and conditions of admission to the ICU (emergency/elective).

RESULTS

Prognostic factors recorded on admission to ICU that were associated with mortality from septicemia among 173 patients were older age, higher admission Apache II score, gastrointestinal surgery, ultimately and rapidly fatal diseases and the number of co-morbidities in addition to the principal diagnosis (active smoking, alcohol abuse, non-cured malignancy, diabetes mellitus, splenectomy, recent antibiotic therapy, major surgery, or major cardiac event). In the multivariate analysis with logistic regression procedures, Apache II and co-morbidities were identified as the two independent predictors of mortality.

CONCLUSIONS

Pre-existing co-morbidities assessed at the admission to the ICU significantly improved the prediction of mortality from septicemia compared to Apache II score alone.