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Bacteriological investigation with reference to puerperal sepsis
1938
PUBLIC
HEALTH
Bacteriological Investigation with Reference to Puerperal Sepsis By F. E. CAMPS, M.D., Pathologist to the Chelmsford and Essex Hospital, and Consulting Pathologist to the Essex County Council.
2. Infections of breast S. aureus 3. Infections of urinary tract B. coli communis S. aureus 4. Other infections e.g., Typhoid fever, tuberculosis. Examination of the above list shows that the majority of the extra-genital infections would be diagnosed on clinical grounds. With regard to the infections of genital origin, however, the importance of immediate bacteriological examination upon the occurrence of rise in temperature in the puerperium lies in the determination of whether or not haemolytic streptococci are concerned. Such an infection is the most serious both from the point of view of the patient and in regard to the spread of infection to other people. The routine examination should be designed to identify the causative organism if the Str. pyogenes is not present. For this purpose the following examinations would be essential stressing in particular the vaginal swab. A. Examination of the patient. 1. Cervical or vaginal swab. To identify infecting organism with particular reference to A. Infections primarily of the genital tract itself. Str. pyogenes. Infecting organism 1. Infections from without 2. Blood culture.--To determine whether septiRoutes Str. pyogenes caemia is present and to identify the infectB. coli communis 1 Droplet direct or indirect ing organism if possible. Both aerobic and Pneumococcus from attendants anaerobic cultures would be done. S. aureus 2 Droplet from patient, 3. Throat swab.--To eliminate the patient as e.g., hands the source of her own infection or as suffer3 Utensils ing from an upper respiratory infection. 4 Air 4. Nasal sWab.~For similar reasons as 3. 5 Swabbing of vulva B. Examination of Contacts. Procedure to be Anaerobic cocci followed in streptococcal infections. 2. Infections from within Anaerobic bacilli Route In the event of haemolytic streptococci being Abrasions as result of Anaerobic gasgrown from the uterine discharges a test should trauma from normal or forming organisms be made to ascertain to which of the groups they instrumental delivery caus- S. aureus belong, and Group A is the most important human ing infection of patient by B. coli communis pathogenic streptococcus. An attempt should also vaginal or rectal organisms. Gonococcus be made to ascertain the possible source of infection and swabs should be taken from all contacts; B. Infections other than those of genital tract. both the nose and the throat being swabbed as 1. Infections of upper respirawell as sore places, etc. All contacts found to be tory tract carriers of Group A streptococci must be forbidden e.g., (a) Pneumonia Str. pyogenes any association with women in the puerperium (b) Tonsillitis Pneumoeoccus until they are free from infection as shown by a negative bacteriological examination of three suc*Paper read to the Home Counties Branch, Society of cessive swabs. It must be understood that the Medical Officers of Health, May 6th, 1938.
The composition of a paper upon this subject is most difficult as it is essential to steer a narrow course between the theoretical ideals and the practical performance of them, for it is in the latter that the Medical Officer of Health is most interested. It is proposed to deal first with the investigation of outbreaks of puerperal sepsis and then with the prophylactic measures which should be adopted, both from the point of view of the patient and of the legal liability of the attendants. The term puerperal sepsis comprises a variety of clinical conditions; and it is suggested that it should be taken in its broadest sense, namely, any pyrexia in the puerperium. Every pyrexia in the puerperium demands investigation, so that the diagnosis can be established at the earliest possible moment, the patient be given the immediate benefit of modern treatment, and the exposure of other mothers to the risk of infection from the same source be avoided. It is essential in order to carry out such an investigation to have in mind the clinical conditions, and the pathogenic agents which may be the cause of puerperal pyrexia. These may be summarised as follows : - -
355
PUBLIC HEALTH carriers of Group A found, may or may not, include the actual source of infection which can only be determined with some degree of probability by more vigorous serological methods of identification. These latter, which are not yet practicable for routine use and "can only be undertaken in laboratories with special experience, will be described later. They have, however, been of value in confirming the importance of carriers in the epidemiology of puerperal sepsis. Apart from the danger to other cases it is quite apparent that should a midwifery attendant who is known to be carrying Str. pyogenes in the throat be employed in midwifery practice and a case of puerperal sepsis result, then it would constitute negligence in law. Thus far this paper has been concerned with the case of puerperal sepsis after it has occurred and in the investigation of the case and its contacts; it is now proposed to deal with the prevention of the occurrence of such cases, which is a far more difficult and controversial problem. The ideal would be to have a Service of midwifery attendants whose upper respiratory passages are free from the presence of Str. pyogenes. To attain such an ideal is an obvious impossibility, as it would mean segregating them completely and permanently, since no scheme of bacteriological tests would infallibly exclude every carrier from attendance on a patient. On the one hand we know that it is possible for persons to carry the Str. pyogenes in their throats for a long time without infecting anybody else as has been demonstrated in the study of closed communities, yet on the other hand we" also know that persons harbouring the Str. pyogenes either following a recent infection or because they have been in contact with a person suffering from an infection due to this organism can transmit the infection to other people. Unfortunately we have no laboratory tests to show when the organism is in the infectious state. We do have reason to believe, however, that persons who have unhealthy throats and who are carrying the Str. pyogenes are more likely to be a source of infection to others. By taking such knowledge into consideration it is possible to formulate some sort of criterion to be demanded in the formation of a midwifery service. Before engaging a midwife she should be asked whether she has recently been suffering from a cold or sore throat or whether she has been in contact with any case of infection which might have been streptococcal in aetiology. If any of these questions are answered in the affirmative then the nose and throat should be examined bacteriologically. In addition her throat should be examined by an oto-rhino-laryngologist to exclude any evidence of clinical abnormality, which if re356
SEPTEMBER ported present is indication for bacteriological examination and exclusion of the presence of Str. pyogenes. The same rule should also apply to all employees in maternity homes, including the domestic staff. Similarly all persons engaged in the practice of midwifery who find themselves to be suffering from any infection of the upper respiratory tract or who have knowingly been in contact with a case of streptococcal infection should immediately cease midwifery until proved to be free from infection with haemolytic streptococci. Nobody realises more than I do the difficulties which present themselves, but one cannot h e l p being most impressed with the number of puerperal sepsis cases in which the original source of infection can be traced to an attendant who had a " cold " which was regarded as trivial at the time. In respect to midwifery practice in private houses it is equally important to exclude any possibility of infection being present amongst the inmates, and hence before the confinement is due it is essential to examine each person for evidence of streptococcal infection such as otitis media, rhinorrhoea or sore throat. If there is such evidence then the patient should be removed from her surroundings, care being taken to prove that she has not already acquired infection before admitting her to a maternity hospital. There is no need to mention the dangers of common nursing staffs for medical, surgical and midwifery patients in hospital, as these can easily be appreciated from the observations already made; indeed one should enforce the rule that midwifery and general hospital nurses should not be in contact with one another in their daily life.
The Serological Classification of the Haemolytic Streptococci It is essential to have some knowledge of the most recent classification of the beta haemolytic streptococci to follow the rationale of the bacteriological procedure in the investigation of puerperal sepsis. The following table gives a brief summary of this.
Classification by means of the precipitin reaction (Lancefield) This depends upon the Group specific polysaccharide which is known as the C. substance and so far the following groups have been defined. Group A. The great majority of strains pathogenic to man fall into this group. Group A strains can also infect the udder of the cow and cause infection which will lead to excretion in the milk. Group B. This is associated with mastitis in cows and has also been isolated from the throats and vaginas of h u m a n beings.
1938 In the former condition it is possible that it was conveyed there by milk. Recently evidence has been obtained to show that certain strains of this group are pathogenic to man. Group C. This has been isolated from lesions in animals and has also been recovered from human beings. There is definite evidence that some strains are pathogenic to man. Groups D, E and F. There is as yet no proof that these groups are pathogenic to man. Group G. This has been isolated from the respiratory tract in human beings and there is reason to suggest that some strains are pathogenic. Thus by determining the serological group of a strain it can be shown to be definitely pathogenic, possibly pathogenic or non-pathogenic. The classification can be of value in dealing with potentially infectious persons, as, for example, midwives on engagement, but it is of limited value in tracing epidemics and cannot be used to demonstrate the source of infection in a case of puerperal sepsis. For the latter a finer differentiation such as the identification of types in Group A is essential.
Classification by means of serological typing (ariffith) Each type in Group A possesses a special antigenic structure, the type specific element termed by Lancefield the M substance is a nucleo-protein. Griflith has prepared type specific scra and has distinguished thirty types of Str. pyogenes. The original strains from which the sera were prepared were from cases of scarlet fever, puerperal fever and from the respiratory tracts of nasopharyngeal infections in schools. Grouping of the above types by the precipitin test has shown that 26 fall into Group A, whilst the remaining four, types 7, 16, 20 and 21, are in G r o u p s C a n d G . I h a v e myself recovered both types 7 and 16 in pure culture from abscesses. One of the chief values of typing is in the study of the epidemiology of streptococcal infection, for it has been due to this that the whole problem of "Relapse " cases in scarlet fever and the fact that cases infected with the same strain may or may not have a rash, have been cleared up. From this classification it is clear that the report of the mere presence of haemolytic streptococci in a specimen may be of doubtful value unless the group is identified, since not all groups of haemolytic streptococci are pathogenic to man. We must know that it is pathogenic, that is to say that it is Str. pyogenes, for that is the broad definition of the term.
PUBLIC HEALTH The question of what is the correct media to use for the growth of the organism is important, as from experience it is evident that human blood agar is not satisfactory and that horse blood agar is best and should be prepared from trypsinised meat broth. One feels that until this media is standardised we are unlikely to obtain uniformly accurate results. Furthermore, it is most advisable that plates are used so that the colony appearance may be studied, as the latter is of great value in identification, especially as it is known that some strains of Str. pyogenes may produce little or no haemolysis and hence may be missed if the appearances of the colonies are not known or studied. Finally, the importance of taking the swab in a proper manner cannot be stressed too much, as badly taken swabs are one of the commonest causes of poor results. Sterile swabs are sometimes received and this may be due to the use of antiseptics.
Summary 1. It is essential to investigate all cases of pyrexia in the pueperium at the earliest possible moment. 2. If infection is shown to be due to Str. pyogenes it is essential to attempt to trace it to its probable source. 3. Education of attendants to report colds or sore throats with a view to exclusion of Str. pyogenes is essential. 4. The criteria demanded before engagement of midwives and employees in maternity homes are discussed. 5. A brief classification of beta haemolytic streptococci has been included as an aid to interpretation of re.ports .and the methods of bacteriological examinauon m puerperal sepsas have been indicated.
Acknowledgments I wish to make acknowledgment to the following workers :--Allison, V. D.; Colebrook, D.; Colebrook, L.; Fry, R. M.; Griffith, F.; Hare, R.; and Lancefield, R., from whose publications I have extracted many of the details recorded.
PREVENTION OF DENTAL DECAY.--Copies of the
leaflet approved by the Council of the Society of Medical Officers of Health on this subject have been obtained by many local authorities for propaganda purposes. The leaflet is now available printed in large type on a cardboard sheet, 30 inches by 20 inches, suitable for display in welfar centres and dental clinics. Copies can be obtained at 2s. 9d. each, post free, from the Executive Secretary of the Society, 1, Thornhaugh Street, Russell Square, W.C.1. 357
PUBLIC
HEALTH
Bacteriological Investigation with Reference to Puerperal Sepsis By F. E. CAMPS, M.D., Pathologist to the Chelmsford and Essex Hospital, and Consulting Pathologist to the Essex County Council.
2. Infections of breast S. aureus 3. Infections of urinary tract B. coli communis S. aureus 4. Other infections e.g., Typhoid fever, tuberculosis. Examination of the above list shows that the majority of the extra-genital infections would be diagnosed on clinical grounds. With regard to the infections of genital origin, however, the importance of immediate bacteriological examination upon the occurrence of rise in temperature in the puerperium lies in the determination of whether or not haemolytic streptococci are concerned. Such an infection is the most serious both from the point of view of the patient and in regard to the spread of infection to other people. The routine examination should be designed to identify the causative organism if the Str. pyogenes is not present. For this purpose the following examinations would be essential stressing in particular the vaginal swab. A. Examination of the patient. 1. Cervical or vaginal swab. To identify infecting organism with particular reference to A. Infections primarily of the genital tract itself. Str. pyogenes. Infecting organism 1. Infections from without 2. Blood culture.--To determine whether septiRoutes Str. pyogenes caemia is present and to identify the infectB. coli communis 1 Droplet direct or indirect ing organism if possible. Both aerobic and Pneumococcus from attendants anaerobic cultures would be done. S. aureus 2 Droplet from patient, 3. Throat swab.--To eliminate the patient as e.g., hands the source of her own infection or as suffer3 Utensils ing from an upper respiratory infection. 4 Air 4. Nasal sWab.~For similar reasons as 3. 5 Swabbing of vulva B. Examination of Contacts. Procedure to be Anaerobic cocci followed in streptococcal infections. 2. Infections from within Anaerobic bacilli Route In the event of haemolytic streptococci being Abrasions as result of Anaerobic gasgrown from the uterine discharges a test should trauma from normal or forming organisms be made to ascertain to which of the groups they instrumental delivery caus- S. aureus belong, and Group A is the most important human ing infection of patient by B. coli communis pathogenic streptococcus. An attempt should also vaginal or rectal organisms. Gonococcus be made to ascertain the possible source of infection and swabs should be taken from all contacts; B. Infections other than those of genital tract. both the nose and the throat being swabbed as 1. Infections of upper respirawell as sore places, etc. All contacts found to be tory tract carriers of Group A streptococci must be forbidden e.g., (a) Pneumonia Str. pyogenes any association with women in the puerperium (b) Tonsillitis Pneumoeoccus until they are free from infection as shown by a negative bacteriological examination of three suc*Paper read to the Home Counties Branch, Society of cessive swabs. It must be understood that the Medical Officers of Health, May 6th, 1938.
The composition of a paper upon this subject is most difficult as it is essential to steer a narrow course between the theoretical ideals and the practical performance of them, for it is in the latter that the Medical Officer of Health is most interested. It is proposed to deal first with the investigation of outbreaks of puerperal sepsis and then with the prophylactic measures which should be adopted, both from the point of view of the patient and of the legal liability of the attendants. The term puerperal sepsis comprises a variety of clinical conditions; and it is suggested that it should be taken in its broadest sense, namely, any pyrexia in the puerperium. Every pyrexia in the puerperium demands investigation, so that the diagnosis can be established at the earliest possible moment, the patient be given the immediate benefit of modern treatment, and the exposure of other mothers to the risk of infection from the same source be avoided. It is essential in order to carry out such an investigation to have in mind the clinical conditions, and the pathogenic agents which may be the cause of puerperal pyrexia. These may be summarised as follows : - -
355
PUBLIC HEALTH carriers of Group A found, may or may not, include the actual source of infection which can only be determined with some degree of probability by more vigorous serological methods of identification. These latter, which are not yet practicable for routine use and "can only be undertaken in laboratories with special experience, will be described later. They have, however, been of value in confirming the importance of carriers in the epidemiology of puerperal sepsis. Apart from the danger to other cases it is quite apparent that should a midwifery attendant who is known to be carrying Str. pyogenes in the throat be employed in midwifery practice and a case of puerperal sepsis result, then it would constitute negligence in law. Thus far this paper has been concerned with the case of puerperal sepsis after it has occurred and in the investigation of the case and its contacts; it is now proposed to deal with the prevention of the occurrence of such cases, which is a far more difficult and controversial problem. The ideal would be to have a Service of midwifery attendants whose upper respiratory passages are free from the presence of Str. pyogenes. To attain such an ideal is an obvious impossibility, as it would mean segregating them completely and permanently, since no scheme of bacteriological tests would infallibly exclude every carrier from attendance on a patient. On the one hand we know that it is possible for persons to carry the Str. pyogenes in their throats for a long time without infecting anybody else as has been demonstrated in the study of closed communities, yet on the other hand we" also know that persons harbouring the Str. pyogenes either following a recent infection or because they have been in contact with a person suffering from an infection due to this organism can transmit the infection to other people. Unfortunately we have no laboratory tests to show when the organism is in the infectious state. We do have reason to believe, however, that persons who have unhealthy throats and who are carrying the Str. pyogenes are more likely to be a source of infection to others. By taking such knowledge into consideration it is possible to formulate some sort of criterion to be demanded in the formation of a midwifery service. Before engaging a midwife she should be asked whether she has recently been suffering from a cold or sore throat or whether she has been in contact with any case of infection which might have been streptococcal in aetiology. If any of these questions are answered in the affirmative then the nose and throat should be examined bacteriologically. In addition her throat should be examined by an oto-rhino-laryngologist to exclude any evidence of clinical abnormality, which if re356
SEPTEMBER ported present is indication for bacteriological examination and exclusion of the presence of Str. pyogenes. The same rule should also apply to all employees in maternity homes, including the domestic staff. Similarly all persons engaged in the practice of midwifery who find themselves to be suffering from any infection of the upper respiratory tract or who have knowingly been in contact with a case of streptococcal infection should immediately cease midwifery until proved to be free from infection with haemolytic streptococci. Nobody realises more than I do the difficulties which present themselves, but one cannot h e l p being most impressed with the number of puerperal sepsis cases in which the original source of infection can be traced to an attendant who had a " cold " which was regarded as trivial at the time. In respect to midwifery practice in private houses it is equally important to exclude any possibility of infection being present amongst the inmates, and hence before the confinement is due it is essential to examine each person for evidence of streptococcal infection such as otitis media, rhinorrhoea or sore throat. If there is such evidence then the patient should be removed from her surroundings, care being taken to prove that she has not already acquired infection before admitting her to a maternity hospital. There is no need to mention the dangers of common nursing staffs for medical, surgical and midwifery patients in hospital, as these can easily be appreciated from the observations already made; indeed one should enforce the rule that midwifery and general hospital nurses should not be in contact with one another in their daily life.
The Serological Classification of the Haemolytic Streptococci It is essential to have some knowledge of the most recent classification of the beta haemolytic streptococci to follow the rationale of the bacteriological procedure in the investigation of puerperal sepsis. The following table gives a brief summary of this.
Classification by means of the precipitin reaction (Lancefield) This depends upon the Group specific polysaccharide which is known as the C. substance and so far the following groups have been defined. Group A. The great majority of strains pathogenic to man fall into this group. Group A strains can also infect the udder of the cow and cause infection which will lead to excretion in the milk. Group B. This is associated with mastitis in cows and has also been isolated from the throats and vaginas of h u m a n beings.
1938 In the former condition it is possible that it was conveyed there by milk. Recently evidence has been obtained to show that certain strains of this group are pathogenic to man. Group C. This has been isolated from lesions in animals and has also been recovered from human beings. There is definite evidence that some strains are pathogenic to man. Groups D, E and F. There is as yet no proof that these groups are pathogenic to man. Group G. This has been isolated from the respiratory tract in human beings and there is reason to suggest that some strains are pathogenic. Thus by determining the serological group of a strain it can be shown to be definitely pathogenic, possibly pathogenic or non-pathogenic. The classification can be of value in dealing with potentially infectious persons, as, for example, midwives on engagement, but it is of limited value in tracing epidemics and cannot be used to demonstrate the source of infection in a case of puerperal sepsis. For the latter a finer differentiation such as the identification of types in Group A is essential.
Classification by means of serological typing (ariffith) Each type in Group A possesses a special antigenic structure, the type specific element termed by Lancefield the M substance is a nucleo-protein. Griflith has prepared type specific scra and has distinguished thirty types of Str. pyogenes. The original strains from which the sera were prepared were from cases of scarlet fever, puerperal fever and from the respiratory tracts of nasopharyngeal infections in schools. Grouping of the above types by the precipitin test has shown that 26 fall into Group A, whilst the remaining four, types 7, 16, 20 and 21, are in G r o u p s C a n d G . I h a v e myself recovered both types 7 and 16 in pure culture from abscesses. One of the chief values of typing is in the study of the epidemiology of streptococcal infection, for it has been due to this that the whole problem of "Relapse " cases in scarlet fever and the fact that cases infected with the same strain may or may not have a rash, have been cleared up. From this classification it is clear that the report of the mere presence of haemolytic streptococci in a specimen may be of doubtful value unless the group is identified, since not all groups of haemolytic streptococci are pathogenic to man. We must know that it is pathogenic, that is to say that it is Str. pyogenes, for that is the broad definition of the term.
PUBLIC HEALTH The question of what is the correct media to use for the growth of the organism is important, as from experience it is evident that human blood agar is not satisfactory and that horse blood agar is best and should be prepared from trypsinised meat broth. One feels that until this media is standardised we are unlikely to obtain uniformly accurate results. Furthermore, it is most advisable that plates are used so that the colony appearance may be studied, as the latter is of great value in identification, especially as it is known that some strains of Str. pyogenes may produce little or no haemolysis and hence may be missed if the appearances of the colonies are not known or studied. Finally, the importance of taking the swab in a proper manner cannot be stressed too much, as badly taken swabs are one of the commonest causes of poor results. Sterile swabs are sometimes received and this may be due to the use of antiseptics.
Summary 1. It is essential to investigate all cases of pyrexia in the pueperium at the earliest possible moment. 2. If infection is shown to be due to Str. pyogenes it is essential to attempt to trace it to its probable source. 3. Education of attendants to report colds or sore throats with a view to exclusion of Str. pyogenes is essential. 4. The criteria demanded before engagement of midwives and employees in maternity homes are discussed. 5. A brief classification of beta haemolytic streptococci has been included as an aid to interpretation of re.ports .and the methods of bacteriological examinauon m puerperal sepsas have been indicated.
Acknowledgments I wish to make acknowledgment to the following workers :--Allison, V. D.; Colebrook, D.; Colebrook, L.; Fry, R. M.; Griffith, F.; Hare, R.; and Lancefield, R., from whose publications I have extracted many of the details recorded.
PREVENTION OF DENTAL DECAY.--Copies of the
leaflet approved by the Council of the Society of Medical Officers of Health on this subject have been obtained by many local authorities for propaganda purposes. The leaflet is now available printed in large type on a cardboard sheet, 30 inches by 20 inches, suitable for display in welfar centres and dental clinics. Copies can be obtained at 2s. 9d. each, post free, from the Executive Secretary of the Society, 1, Thornhaugh Street, Russell Square, W.C.1. 357