AMERICAN
Journal of Epidemiology VOL. 101
FEBRUARY, 1975
NO. 2
Reviews and Commentary NOSOCOMIAL INFECTIONS THEODORE C. EICKHOFF1
a rational program of study and control has been vigorously advocated by the Center for Disease Control (1), the American Hospital Association (2), and other official bodies including the Joint Commission on Accreditation of Hospitals (3). In order to maintain accreditation it is necessary for a hospital to have an Infection Committee which meets periodically and attempts to assess, on a continuing basis, the character and magnitude of nosocomial infections within that hospital. Just how many such surveillance programs function with a reasonable degree of effectiveness is unfortunately more a matter for conjecture, rather than factual data. A timely and entirely pertinent question to address at this point is whether effective surveillance programs have led to a reduction in nosocomial infections. In no instance has this been shown to be the case in any United States hospital in the context of a valid epidemiologic study; indeed, the conduct of such a study would seem to bring about a philosophic impasse because of the necessity of measuring disease in the control population. Thus, that question cannot be answered in a satisfactory fashSURVEILLANCE ion. A second question that might be adThe concept of surveillance of nosocomial infections as the necessary first step in dressed is whether infection control activities resulting from surveillance have led to 1 Division of Infectious Disease, University of Colo- a reduction in nosocomial infections, as rado Medical Center, 4200 East 9th Avenue, Denver, measured by morbidity and mortality. In Colorado 80220. Hospital associated infections, or nosocomial infections, are by no means a new problem. They undoubtedly existed from the time sick people were first gathered together for care. In the past 20 years, however, several factors have operated to stimulate both an awareness of and an intense research interest in nosocomial infections. Such factors have included antimicrobial therapy and the emergence of drug resistance in bacteria, the mushrooming technology of modern medicine, and the diagnostic and therapeutic advances which have enabled us to, among other things, generate and maintain increasing populations of patients who are to some degree "compromised" hosts. The field of nosocomial infections has not lacked for competent investigators, nor for ardent advocates of one or another point of view, or control measure. Sound and careful epidemiologic studies in this area, however, are in continuing dire need. This commentary will deal with several concerns: surveillance, environmental control, and the apparent dichotomy between research and its application.
93
Downloaded from https://academic.oup.com/aje/article-abstract/101/2/93/62904 by University of Western Sydney user on 12 January 2019
Formerb AMERICAN JOURNAL OF HYGIENE
94
THEODORE C. EICKHOFF
ENVIRONMENTAL CONTROL
Particularly disturbing to this observer has been the tendency in some quarters to equate hospital infection control with what might be termed "microbiological surveillance." Thus, bacteria in the air, on walls, floors, linen, ice dispensers, and even flower vases are dutifully enumerated, all with the implication that there exist some standards, the exceeding of which is known to increase the risk of nosocomial infection. Only one recent example is cited (4). This is simply not the case. I do not suggest that well-planned studies of environmental reservoirs of hospital pathogens are unnecessary or inappropriate; quite the contrary is true. I do suggest that environmental sampling procedures, unless done in the context of a specific epidemiologic study or in pursuit of a specific identified problem in a hospital, have not been rewarding and should be abandoned. There should be neither administrative nor medicolegal compulsion for hospitals to carry out demonstrably unnecessary or irrelevant procedures in an effort to control nosocomial infections. Another aspect of environmental control in hospitals has been of increasing concern in the past several years. This is the quality control of material said to be sterile and distributed through commercial sources to hospitals. This includes virtually all "sterile" disposable supplies, catheters, administration sets, intravenous fluids, as well as prostheses of various kinds which are ultimately inserted into patients. Contamination of these items, for which sterility has been claimed by the manufacturer, has been documented for antiseptics used for urinary tract catheterization (5), intravenous fluids from several manufacturers (6), and most recently, the intravenous catheters made by a major manufacturer (7). In all instances save the last, serious disease was associated with the contaminated items. What can be done to assure the con-
Downloaded from https://academic.oup.com/aje/article-abstract/101/2/93/62904 by University of Western Sydney user on 12 January 2019
other words, are our control measures at all effective in doing what we want them to do? This question can be asked, and more importantly, deserves to be answered. Partial answers to this question can be found in studies focused on one or another specific high-risk procedure within hospitals, such as the use of urinary tract catheters or intravenous catheters. One cannot presently find documentation, however, of the benefit to be gained in terms of decreased morbidity and mortality by instituting an overall hospital infection control program. Of equal importance, and equally lacking, are determinations of the cost-effectiveness of hospital infection control activities. Hospitals of 300 to 500 beds may easily spend $100 per bed per year on such activities, including a nurse-epidemiologist, part-time hospital epidemiologist, secretarial and laboratory support, not including the donated professional time of committee members. It would seem only prudent to justify such an expenditure by documentation of reduced hospital costs, more efficient use of hospital beds, reduced length of hospital stay, or similar economic indices of reduced morbidity and mortality. Another function of surveillance is to identify potential problems as quickly as possible, an "alert" mechanism, so that corrective action can be taken promptly. Virtually every hospital that conducts surveillance can probably identify instances in which problems were identified, action taken, and an outbreak of nosocomial infection aborted or averted. Lacking, however, is an appreciation of just how comprehensive and thorough surveillance must be in order to perform this role. Is it necessary to record each nosocomial infection that occurs? Or would surveillance of certain indicator or "sentinal" infections such as bacteremia accomplish the same goal more economically? As hospital costs continue to mount, answers to these questions become increasingly important to obtain.
NOSOCOMIAL INFECTIONS
KNOWLEDGE, OLD AND NEW
Two significant conferences on nosocomial infections have taken place within the past five years. These were the International Conference on Nosocomial Infections held at the Center for Disease Control, in August 1970, and a Workshop on Hospital Associated Infections, sponsored by the National Institute of Allergy and Infectious Diseases, National Institutes of Health, in December 1972. In both of these conferences, two divergent but not mutually exclusive attitudes were apparent. The first held that a great deal of knowledge of the epidemiology of nosocomial infections was already well established, and that if such knowledge were put into regular practice in hospitals, substantial reductions in the frequency of nosocomial infections could be anticipated. The major defect thus has been a failure to communicate ideas effectively, and to convince our clinical colleagues of the importance of observing measures designed to reduce nosocomial infections. We have somehow not convinced them that their patients would get better faster if this were the case. This is particularly true in the case of infections associated with urinary tract catheterization and intravenous catheterization. The other and contrasting opinion was
that there are still many areas in which our knowledge is deficient, and that control of many kinds of hospital infection might be greatly facilitated with new knowledge, particularly in the broad areas of host defense mechanisms and the epidemiology of infections occurring in immunosuppressed hosts. Furthermore, effective control of hospital-associated infection might be obtained more economically by a critical evaluation of many of the environmental control techniques currently employed or recommended. There is, of course, truth in both of these concepts. Virtually every survey of hospitalassociated infections has demonstrated that infections of the urinary tract regularly account for a third or more of all nosocomial infections (8-10). The association of infection of the urinary tract with prior instrumentation and/or catheterization is similarly well documented. Kunin and McCormack (11) and Martin and Bookrajian (12) have clearly demonstrated that careful management of urinary tract catheters can effect a substantial reduction in urinary tract infection and subsequent gram negative sepsis. There is thus strong indication that this message has not been heeded, and one need spend only a short while observing the management of urinary tract catheters in a hospital to appreciate this. A second area in which there is both clear documentation of risk and obvious preventive measures that could be applied is that of intravenous catheters. The risk of catheter-associated septicemia is clearly shown to increase with time that a catheter is left in place (6), yet in only a few hospitals can one find careful adherence to preventive measures requiring that leaving a catheter in place longer than 48 hours be justified by a note in the chart. There are, then, two areas in which the risk is quite clearly documented, and in which relatively little in the way of aggres-
Downloaded from https://academic.oup.com/aje/article-abstract/101/2/93/62904 by University of Western Sydney user on 12 January 2019
sumer, the hospital, the physician, and finally the patient, that materials claimed by a manufacturer to be sterile are indeed so? For individual hospitals to undertake sampling programs of their own in order to achieve quality control of these items is neither technically nor economically possible. At the moment, there appears to be little assurance of quality control and sterility of such items beyond the good name of the manufacturer. Experience of the past several years, however, suggests that this may not be sufficient, and that closer scrutiny by the relevant regulatory agency, in this case the Food and Drug Administration, may be highly desirable.
95
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THEODORE C. EICKHOFF
investigation. Polyvalent pseudomonas vaccine has shown promise in burn patients (22), but was of only limited value in patients with neoplastic disease (23). 4) Many risk factors within the hospital are inadequately defined at present. There is need for critical epidemiologic evaluation to define the risk associated with given diseases and given procedures more fully. Substantial progress has been made, for example, in defining the risk factors contributing to colonization and suprainfection of the respiratory tract (24-26). To carry this problem one step further, how often are patients unnecessarily exposed to significant risk factors? 5) Within the context of such epidemiologic studies, estimates of cost effectiveness of many commonly employed techniques and procedures in hospital infection control should be made. How many of these are actually useful? For example, is it necessary that floors be washed with germides? Are laminar air-flow techniques useful in the reduction of post-operative wound infections, or in infections among immunosuppressed hosts? All of the more expensive techniques currently being recommended in some quarters for infection control must be evaluated critically as to their cost-benefit ratio before they can be generally recommended for use. Ultimately some difficult decisions must be made by a society whose economic resources are not unlimited. 6) Finally, there need to be encouraged innovative approaches to more effective communication, to improving the dissemination and utilization of knowledge concerning antimicrobial agents, hazards of various invasive procedures, and hospital infection control practices. Hospital infection committees may well have succeeded least where it ultimately counts, that is, in influencing human behavior. The factors that operate to make an infection control program alive and effective in some hospitals in contrast to others may be
Downloaded from https://academic.oup.com/aje/article-abstract/101/2/93/62904 by University of Western Sydney user on 12 January 2019
sive controls are to be found. As pointed out by Kass, "it surely must be apparent that the sacred voluntary approach has serious drawbacks if this type of inadequacy can be so frequently documented" (13). It would be altogether gratuitous to point out that more research is needed in many aspects of nosocomial infection and their control. More to the point would be a delineation of several areas in which additional studies might lead to clinically or epidemiologically useful information. 1) More rapid and efficient diagnostic systems, both to detect environmental contamination and to detect infection such as bacterial pneumonias, represent a major need. The nationwide epidemic of contaminated intravenous fluids (14) indicates the need for systems to detect in-use contamination of sterile products promptly. Standard techniques for the diagnosis of infections such as bacterial pneumonia long ago reached their maximum efficiency, but are still often equivocal, inaccurate, and time-consuming. 2) The increasing number of compromised or immunosuppressed hosts in hospitals was alluded to previously. The need for improved diagnostic as well as therapeutic techniques for the unusual infections that occur in such patients is evident to anyone who is responsible for their care. More important, however, is our lack of appreciation of the epidemiology of such infections. There is, for example, little understanding at present of whether such "opportunistic pathogens" are part of our normal flora, or are acquired within the hospital. Can immunosuppressive techniques be more specifically "targeted" to accomplish their therapeutic goal and yet leave defense mechanisms against infectious agents intact? 3) The possibility of producing crossreactive immunity through shared antigens (15-17), or core antigenic materials (18-21), warrants a great deal of additional
NOSOCOMIAL INFECTIONS
97
14. Center for Disease Control: Nosocomial bacteremias associated with intravenous fluid REFERENCES therapy—U.S.A. Morbidity and Mortality Weekly Report 20(suppl 9), 1971 Garner JS, Bennett JV. Scheckler WE, et al: 15. Grados O, Ewing WH: Antigenic relationship Surveillance of Nosocomial Infections. Proceedbetween Escherichia coli and Neisseria ings of the International Conference on Nosocomeningitidis group B. J Infect Dis 122:100-103, mial Infections. American Hospital Association, 1970 Chicago, 1971, pp 277-281 16. Myerowitz RL, Schneerson R, Turck M, et al: Infection Control in the Hospital. American HosUrinary tract Escherichia coli with cross-reactive pital Association, Chicago, 1970 antigens to encapsulated pyogenic bacteria. LanStandards for Accreditation of Hospitals. Joint cet 1:467-570, 1973 Commission on Accreditation of Hospitals, Chi17. Myerowitz RL, Gordon RE, Robbins JB: Polysaccago, October, 1969 charides of the genus bacillus cross-reactive with Walter CW: Role of bacteriologic survey cultures the capsular polysaccharides of Diplococcus in control of nosocomial infection. JAMA pneumoniae type III, Haemophilus influenzae 229:578-579, 1974 type B, and Neisseria meningitidis group A. Hardy PC, Ederer GM, Matsen JM: ContaminaInfect Immun 8:896-900, 1973 tion of commercially packaged urinary cathether 18. Chedid L, Parant M. Parant F, et al: A proposed kits with pseudomonad EO-1. N Engl J Med mechanism for natural immunity to enterobacte282:33-35, 1970 rial pathogens. J Immunol 100:292-301, 1968 Maki DG, Goldman DA, Rhame FS: Infection 19. Galanos C, Luderitz O, Westphal O: Preparation control in intravenous therapy. Ann Intern Med and properties of antisera against the lipid A 79:867-887, 1973 component of bacterial lipopolysaccharides. Eur Center for Disease Control. Recall of contamiJ Biochem 24:116-122, 1971 nated intravenous cannulae—United States. 20. McCabe WR: Immunization with R mutants of S. Morbidity and Mortality Weekly Report minnesota. I. Protection against challenge with 23(7):57-58, 1974 heterologous gram-negative bacilli. J Immunol Adler JL, Burke JP, Finland M: Infection and 108:601-610, 1972 antibiotic usage at Boston City Hospital, January 21. McCabe WR, Kreger BE, Johns M: Type-specific 1970. Arch Intern Med 127:460-465, 1971 and cross-reactive antibodies in gram-negative Thoburn R, Fekety FR Jr, Cluff LE, et al: bacteremia. N Engl J Med. 287:261-267, 1972 Infections acquired by hospitalized patients. Arch Intern Med 121:1-10, 1968 22. Alexander JW, Fisher MW, MacMillan BG: Immunological control of Pseudomonas infection in Eickhoff TC, Brachman PS, Bennett JV, et al: , burn patients: A clinical evaluation. Arch Surg Surveillance of nosocomial infections in commu102:31-36, 1971 nity hospitals. I. Surveillance methods, effective23. Young LS, Meyer RD, Armstrong D: Pseudoness, and initial results. J Infect Dis 120:305-317, monas aeruginosa vaccine in cancer patients. Ann 1969 Intern Med 79:518-527, 1973 Kunin CM, McCormack RC: Prevention of ca24. Tillotson JR, Finland M: Bacterial colonization theter-induced urinary tract infections by sterile and clinical superinfection of the respiratory tract closed drainage. N Engl J Med 274:1155-1161, complicating antibiotic treatment of pneumonia. 1966 J Infect Dis 119:597-624, 1969 Martin CM, Bookrajian EN: Bacteriuria preven25. Johanson WG, Pierce AK, Sanford JP, et al: tion after indwelling urinary catheterization. Nosocomial infections with gram-negative bacilli: Arch Intern Med 110:703-711, 1962 The significance of colonization of the respiratory Kass EH: Surveillance as a Control System: tract. Ann Intern Med 77:701-706, 1972 Statement of Panelist. Proceedings of the Inter26. Stevens RM, Teres D, Skillman JJ, et a]: Pneunational Conference on Nosocomial Infections. monia in an intensive care unit: A 30-month American Hospital Association, Chicago, 1971, p experience. Arch Intern Med 134:106-111, 1974 292
a most timely subject for study. 1.
3.
4.
5.
6. ' 7.
8.
9.
10.
11.
12.
13.
Downloaded from https://academic.oup.com/aje/article-abstract/101/2/93/62904 by University of Western Sydney user on 12 January 2019
2.
Journal of Epidemiology VOL. 101
FEBRUARY, 1975
NO. 2
Reviews and Commentary NOSOCOMIAL INFECTIONS THEODORE C. EICKHOFF1
a rational program of study and control has been vigorously advocated by the Center for Disease Control (1), the American Hospital Association (2), and other official bodies including the Joint Commission on Accreditation of Hospitals (3). In order to maintain accreditation it is necessary for a hospital to have an Infection Committee which meets periodically and attempts to assess, on a continuing basis, the character and magnitude of nosocomial infections within that hospital. Just how many such surveillance programs function with a reasonable degree of effectiveness is unfortunately more a matter for conjecture, rather than factual data. A timely and entirely pertinent question to address at this point is whether effective surveillance programs have led to a reduction in nosocomial infections. In no instance has this been shown to be the case in any United States hospital in the context of a valid epidemiologic study; indeed, the conduct of such a study would seem to bring about a philosophic impasse because of the necessity of measuring disease in the control population. Thus, that question cannot be answered in a satisfactory fashSURVEILLANCE ion. A second question that might be adThe concept of surveillance of nosocomial infections as the necessary first step in dressed is whether infection control activities resulting from surveillance have led to 1 Division of Infectious Disease, University of Colo- a reduction in nosocomial infections, as rado Medical Center, 4200 East 9th Avenue, Denver, measured by morbidity and mortality. In Colorado 80220. Hospital associated infections, or nosocomial infections, are by no means a new problem. They undoubtedly existed from the time sick people were first gathered together for care. In the past 20 years, however, several factors have operated to stimulate both an awareness of and an intense research interest in nosocomial infections. Such factors have included antimicrobial therapy and the emergence of drug resistance in bacteria, the mushrooming technology of modern medicine, and the diagnostic and therapeutic advances which have enabled us to, among other things, generate and maintain increasing populations of patients who are to some degree "compromised" hosts. The field of nosocomial infections has not lacked for competent investigators, nor for ardent advocates of one or another point of view, or control measure. Sound and careful epidemiologic studies in this area, however, are in continuing dire need. This commentary will deal with several concerns: surveillance, environmental control, and the apparent dichotomy between research and its application.
93
Downloaded from https://academic.oup.com/aje/article-abstract/101/2/93/62904 by University of Western Sydney user on 12 January 2019
Formerb AMERICAN JOURNAL OF HYGIENE
94
THEODORE C. EICKHOFF
ENVIRONMENTAL CONTROL
Particularly disturbing to this observer has been the tendency in some quarters to equate hospital infection control with what might be termed "microbiological surveillance." Thus, bacteria in the air, on walls, floors, linen, ice dispensers, and even flower vases are dutifully enumerated, all with the implication that there exist some standards, the exceeding of which is known to increase the risk of nosocomial infection. Only one recent example is cited (4). This is simply not the case. I do not suggest that well-planned studies of environmental reservoirs of hospital pathogens are unnecessary or inappropriate; quite the contrary is true. I do suggest that environmental sampling procedures, unless done in the context of a specific epidemiologic study or in pursuit of a specific identified problem in a hospital, have not been rewarding and should be abandoned. There should be neither administrative nor medicolegal compulsion for hospitals to carry out demonstrably unnecessary or irrelevant procedures in an effort to control nosocomial infections. Another aspect of environmental control in hospitals has been of increasing concern in the past several years. This is the quality control of material said to be sterile and distributed through commercial sources to hospitals. This includes virtually all "sterile" disposable supplies, catheters, administration sets, intravenous fluids, as well as prostheses of various kinds which are ultimately inserted into patients. Contamination of these items, for which sterility has been claimed by the manufacturer, has been documented for antiseptics used for urinary tract catheterization (5), intravenous fluids from several manufacturers (6), and most recently, the intravenous catheters made by a major manufacturer (7). In all instances save the last, serious disease was associated with the contaminated items. What can be done to assure the con-
Downloaded from https://academic.oup.com/aje/article-abstract/101/2/93/62904 by University of Western Sydney user on 12 January 2019
other words, are our control measures at all effective in doing what we want them to do? This question can be asked, and more importantly, deserves to be answered. Partial answers to this question can be found in studies focused on one or another specific high-risk procedure within hospitals, such as the use of urinary tract catheters or intravenous catheters. One cannot presently find documentation, however, of the benefit to be gained in terms of decreased morbidity and mortality by instituting an overall hospital infection control program. Of equal importance, and equally lacking, are determinations of the cost-effectiveness of hospital infection control activities. Hospitals of 300 to 500 beds may easily spend $100 per bed per year on such activities, including a nurse-epidemiologist, part-time hospital epidemiologist, secretarial and laboratory support, not including the donated professional time of committee members. It would seem only prudent to justify such an expenditure by documentation of reduced hospital costs, more efficient use of hospital beds, reduced length of hospital stay, or similar economic indices of reduced morbidity and mortality. Another function of surveillance is to identify potential problems as quickly as possible, an "alert" mechanism, so that corrective action can be taken promptly. Virtually every hospital that conducts surveillance can probably identify instances in which problems were identified, action taken, and an outbreak of nosocomial infection aborted or averted. Lacking, however, is an appreciation of just how comprehensive and thorough surveillance must be in order to perform this role. Is it necessary to record each nosocomial infection that occurs? Or would surveillance of certain indicator or "sentinal" infections such as bacteremia accomplish the same goal more economically? As hospital costs continue to mount, answers to these questions become increasingly important to obtain.
NOSOCOMIAL INFECTIONS
KNOWLEDGE, OLD AND NEW
Two significant conferences on nosocomial infections have taken place within the past five years. These were the International Conference on Nosocomial Infections held at the Center for Disease Control, in August 1970, and a Workshop on Hospital Associated Infections, sponsored by the National Institute of Allergy and Infectious Diseases, National Institutes of Health, in December 1972. In both of these conferences, two divergent but not mutually exclusive attitudes were apparent. The first held that a great deal of knowledge of the epidemiology of nosocomial infections was already well established, and that if such knowledge were put into regular practice in hospitals, substantial reductions in the frequency of nosocomial infections could be anticipated. The major defect thus has been a failure to communicate ideas effectively, and to convince our clinical colleagues of the importance of observing measures designed to reduce nosocomial infections. We have somehow not convinced them that their patients would get better faster if this were the case. This is particularly true in the case of infections associated with urinary tract catheterization and intravenous catheterization. The other and contrasting opinion was
that there are still many areas in which our knowledge is deficient, and that control of many kinds of hospital infection might be greatly facilitated with new knowledge, particularly in the broad areas of host defense mechanisms and the epidemiology of infections occurring in immunosuppressed hosts. Furthermore, effective control of hospital-associated infection might be obtained more economically by a critical evaluation of many of the environmental control techniques currently employed or recommended. There is, of course, truth in both of these concepts. Virtually every survey of hospitalassociated infections has demonstrated that infections of the urinary tract regularly account for a third or more of all nosocomial infections (8-10). The association of infection of the urinary tract with prior instrumentation and/or catheterization is similarly well documented. Kunin and McCormack (11) and Martin and Bookrajian (12) have clearly demonstrated that careful management of urinary tract catheters can effect a substantial reduction in urinary tract infection and subsequent gram negative sepsis. There is thus strong indication that this message has not been heeded, and one need spend only a short while observing the management of urinary tract catheters in a hospital to appreciate this. A second area in which there is both clear documentation of risk and obvious preventive measures that could be applied is that of intravenous catheters. The risk of catheter-associated septicemia is clearly shown to increase with time that a catheter is left in place (6), yet in only a few hospitals can one find careful adherence to preventive measures requiring that leaving a catheter in place longer than 48 hours be justified by a note in the chart. There are, then, two areas in which the risk is quite clearly documented, and in which relatively little in the way of aggres-
Downloaded from https://academic.oup.com/aje/article-abstract/101/2/93/62904 by University of Western Sydney user on 12 January 2019
sumer, the hospital, the physician, and finally the patient, that materials claimed by a manufacturer to be sterile are indeed so? For individual hospitals to undertake sampling programs of their own in order to achieve quality control of these items is neither technically nor economically possible. At the moment, there appears to be little assurance of quality control and sterility of such items beyond the good name of the manufacturer. Experience of the past several years, however, suggests that this may not be sufficient, and that closer scrutiny by the relevant regulatory agency, in this case the Food and Drug Administration, may be highly desirable.
95
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THEODORE C. EICKHOFF
investigation. Polyvalent pseudomonas vaccine has shown promise in burn patients (22), but was of only limited value in patients with neoplastic disease (23). 4) Many risk factors within the hospital are inadequately defined at present. There is need for critical epidemiologic evaluation to define the risk associated with given diseases and given procedures more fully. Substantial progress has been made, for example, in defining the risk factors contributing to colonization and suprainfection of the respiratory tract (24-26). To carry this problem one step further, how often are patients unnecessarily exposed to significant risk factors? 5) Within the context of such epidemiologic studies, estimates of cost effectiveness of many commonly employed techniques and procedures in hospital infection control should be made. How many of these are actually useful? For example, is it necessary that floors be washed with germides? Are laminar air-flow techniques useful in the reduction of post-operative wound infections, or in infections among immunosuppressed hosts? All of the more expensive techniques currently being recommended in some quarters for infection control must be evaluated critically as to their cost-benefit ratio before they can be generally recommended for use. Ultimately some difficult decisions must be made by a society whose economic resources are not unlimited. 6) Finally, there need to be encouraged innovative approaches to more effective communication, to improving the dissemination and utilization of knowledge concerning antimicrobial agents, hazards of various invasive procedures, and hospital infection control practices. Hospital infection committees may well have succeeded least where it ultimately counts, that is, in influencing human behavior. The factors that operate to make an infection control program alive and effective in some hospitals in contrast to others may be
Downloaded from https://academic.oup.com/aje/article-abstract/101/2/93/62904 by University of Western Sydney user on 12 January 2019
sive controls are to be found. As pointed out by Kass, "it surely must be apparent that the sacred voluntary approach has serious drawbacks if this type of inadequacy can be so frequently documented" (13). It would be altogether gratuitous to point out that more research is needed in many aspects of nosocomial infection and their control. More to the point would be a delineation of several areas in which additional studies might lead to clinically or epidemiologically useful information. 1) More rapid and efficient diagnostic systems, both to detect environmental contamination and to detect infection such as bacterial pneumonias, represent a major need. The nationwide epidemic of contaminated intravenous fluids (14) indicates the need for systems to detect in-use contamination of sterile products promptly. Standard techniques for the diagnosis of infections such as bacterial pneumonia long ago reached their maximum efficiency, but are still often equivocal, inaccurate, and time-consuming. 2) The increasing number of compromised or immunosuppressed hosts in hospitals was alluded to previously. The need for improved diagnostic as well as therapeutic techniques for the unusual infections that occur in such patients is evident to anyone who is responsible for their care. More important, however, is our lack of appreciation of the epidemiology of such infections. There is, for example, little understanding at present of whether such "opportunistic pathogens" are part of our normal flora, or are acquired within the hospital. Can immunosuppressive techniques be more specifically "targeted" to accomplish their therapeutic goal and yet leave defense mechanisms against infectious agents intact? 3) The possibility of producing crossreactive immunity through shared antigens (15-17), or core antigenic materials (18-21), warrants a great deal of additional
NOSOCOMIAL INFECTIONS
97
14. Center for Disease Control: Nosocomial bacteremias associated with intravenous fluid REFERENCES therapy—U.S.A. Morbidity and Mortality Weekly Report 20(suppl 9), 1971 Garner JS, Bennett JV. Scheckler WE, et al: 15. Grados O, Ewing WH: Antigenic relationship Surveillance of Nosocomial Infections. Proceedbetween Escherichia coli and Neisseria ings of the International Conference on Nosocomeningitidis group B. J Infect Dis 122:100-103, mial Infections. American Hospital Association, 1970 Chicago, 1971, pp 277-281 16. Myerowitz RL, Schneerson R, Turck M, et al: Infection Control in the Hospital. American HosUrinary tract Escherichia coli with cross-reactive pital Association, Chicago, 1970 antigens to encapsulated pyogenic bacteria. LanStandards for Accreditation of Hospitals. Joint cet 1:467-570, 1973 Commission on Accreditation of Hospitals, Chi17. Myerowitz RL, Gordon RE, Robbins JB: Polysaccago, October, 1969 charides of the genus bacillus cross-reactive with Walter CW: Role of bacteriologic survey cultures the capsular polysaccharides of Diplococcus in control of nosocomial infection. JAMA pneumoniae type III, Haemophilus influenzae 229:578-579, 1974 type B, and Neisseria meningitidis group A. Hardy PC, Ederer GM, Matsen JM: ContaminaInfect Immun 8:896-900, 1973 tion of commercially packaged urinary cathether 18. Chedid L, Parant M. Parant F, et al: A proposed kits with pseudomonad EO-1. N Engl J Med mechanism for natural immunity to enterobacte282:33-35, 1970 rial pathogens. J Immunol 100:292-301, 1968 Maki DG, Goldman DA, Rhame FS: Infection 19. Galanos C, Luderitz O, Westphal O: Preparation control in intravenous therapy. Ann Intern Med and properties of antisera against the lipid A 79:867-887, 1973 component of bacterial lipopolysaccharides. Eur Center for Disease Control. Recall of contamiJ Biochem 24:116-122, 1971 nated intravenous cannulae—United States. 20. McCabe WR: Immunization with R mutants of S. Morbidity and Mortality Weekly Report minnesota. I. Protection against challenge with 23(7):57-58, 1974 heterologous gram-negative bacilli. J Immunol Adler JL, Burke JP, Finland M: Infection and 108:601-610, 1972 antibiotic usage at Boston City Hospital, January 21. McCabe WR, Kreger BE, Johns M: Type-specific 1970. Arch Intern Med 127:460-465, 1971 and cross-reactive antibodies in gram-negative Thoburn R, Fekety FR Jr, Cluff LE, et al: bacteremia. N Engl J Med. 287:261-267, 1972 Infections acquired by hospitalized patients. Arch Intern Med 121:1-10, 1968 22. Alexander JW, Fisher MW, MacMillan BG: Immunological control of Pseudomonas infection in Eickhoff TC, Brachman PS, Bennett JV, et al: , burn patients: A clinical evaluation. Arch Surg Surveillance of nosocomial infections in commu102:31-36, 1971 nity hospitals. I. Surveillance methods, effective23. Young LS, Meyer RD, Armstrong D: Pseudoness, and initial results. J Infect Dis 120:305-317, monas aeruginosa vaccine in cancer patients. Ann 1969 Intern Med 79:518-527, 1973 Kunin CM, McCormack RC: Prevention of ca24. Tillotson JR, Finland M: Bacterial colonization theter-induced urinary tract infections by sterile and clinical superinfection of the respiratory tract closed drainage. N Engl J Med 274:1155-1161, complicating antibiotic treatment of pneumonia. 1966 J Infect Dis 119:597-624, 1969 Martin CM, Bookrajian EN: Bacteriuria preven25. Johanson WG, Pierce AK, Sanford JP, et al: tion after indwelling urinary catheterization. Nosocomial infections with gram-negative bacilli: Arch Intern Med 110:703-711, 1962 The significance of colonization of the respiratory Kass EH: Surveillance as a Control System: tract. Ann Intern Med 77:701-706, 1972 Statement of Panelist. Proceedings of the Inter26. Stevens RM, Teres D, Skillman JJ, et a]: Pneunational Conference on Nosocomial Infections. monia in an intensive care unit: A 30-month American Hospital Association, Chicago, 1971, p experience. Arch Intern Med 134:106-111, 1974 292
a most timely subject for study. 1.
3.
4.
5.
6. ' 7.
8.
9.
10.
11.
12.
13.
Downloaded from https://academic.oup.com/aje/article-abstract/101/2/93/62904 by University of Western Sydney user on 12 January 2019
2.
![[Nosocomial infections (author's transl)].](/assets/img/hold.png)
