1222 than
and it represents one of many analyses that done. Another approach to controlling for cigarette smoking and instant coffee consumption is shown in table ii in this letter. The matching has been broken since any large-sample bias thus introduced seems to be fairly negligible and in2 any case would direct the estimate of risk ratio towards unity.2 These data show that instant-coffee consumption is not confounding-neither is cigarette smoking, although it does modify the association in that lifetime non-smokers and current smokers of less than 15 cigarettes a day are not, apparently, at increased risk from artificial-sweetener use, although the estimates are based on small numbers. Your editorial stressed the difference for males and females. We recognise the dangers of arbitrarily subdividing data into categories and analysing data within such arbitrarily defined strata. However, for bladder cancer the distinction between males and females seems to us to be fundamental and not arbitrary and we decided to do this analysis by sex before we knew the results. Possible reasons for the sex discrepancy are chance, a difference between the sexes with respect to carcinogenicity (which, despite the similar finding in animals, you feel to be unlikely), or a bias which particularly affected the female controls. With respect to the latter the percentage users of artificial sweeteners among the female controls in the three areas was far less consistent than for the males (table t). Male cases used more artificial sweeteners per se but did not use more dietetic foods and beverages than male controls, whereas female cases used less artificial sweeteners, less dietetic foods, and less dietetic beverages than did female controls. Dietetic foods and beverages are comparatively new; only 1 of our subjects reported using them more than ten years before interview, whereas among those 13 subjects who indicated the time period when they used artificial sweeteners in tablet or drop form, 10 used them during or before the 1939-45 war. Thus, if artificial sweeteners are carcinogenic (and have the usual long latent period for bladder carcinogenesis) one would anticipate an increased risk associated with the use of tablets or drops but not with the use of dietetic foods or beverages. The reverse effect observed in females is much weaker, because of the smaller numbers. The pattern is, however, consistent with a group of female controls who were overweight and thus used artificial sweeteners, dietetic foods, and dietetic beverages. If the observed association between artificial sweeteners and male bladder cancer is not due to chance, then it must be: (1) real; (2) due to confounding; or (3) due to some systematic bias or error in study design and execution. We feel that table u and other analyses where we have controlled for confounding in other ways adequately cover this issue. None of these analyses indicates that the observed association between artificialsweetener use and bladder cancer in males could be due to confounding by some variable for which we have quantitative information. Neither are we aware of any possible confounding factor which could explain such an association but for which we have no data. The possibility of a systematic bias or error is harder to exclude. Nevertheless, the careful design and execution of our study, the internal consistency of the results, and the agreement between our results and those of previous investigators for variables other than artificial-sweetener use point to the lack of any such bias. Our results helps to clarify those studies which failed to show an effect on bladder-cancer mortality among diabetics. 3Further, they do not contradict the lack of association between the secular trends in bladder-cancer mortality and national patterns of artificial-sweetener consumption6,7 in view of the low attributable risk observed in our study in the general population. Our results differ primarily from those of investi-
definitive,
were
2. 3. 4.
Seigel, D. G., Greenhouse, S. W. J. chron. Dis. 1973, 26, 219. Armstrong, B., Doll, R. Br. J. prev. soc. Med. 1975, 29, 73. Armstong, B., Lee, A. J., Adelstein, A. M., Donovan, J. W., White, G. C., Rittle, S. ibid. 1976, 30, 151. 5. Kessler, I. I. J. natn. Cancer Inst. 1970, 44, 673. 6. Berbank, F., Fraumeni, Jr. J. F. Nature, 1970, 227, 296. 7. Armstrong, B., Doll, R. Br. J. prev. soc Med. 1974, 18, 233.
gators who have carried out previous case/control studies. Essentially, the major and possibly critical difference in design lies in the use of "neighbourhood" as opposed to "hospital" controls. One source of bias in hospital controls is any association between being overweight and the risk of hospital admission. In two of the four reported case/control studies’-" using hospital controls, the frequency of use of artificial sweeteners among male controls
was much higher than in our study (30%8 and 18%9). We agree that the role of artificial sweeteners in the xtiology of bladder cancer requires further study in man, but we feel that our study should not be dismissed and should be given at least equal weighting with the negative findings.
Epidemiology Unit, National Cancer Institute of Canada,
University of Toronto, Toronto, Ontario, Canada
A. B. MILLER G. R. HOWE
APARTHEID AND MENTAL HEALTH CARE
SIR,-Iam surprised that The Lancet should comment (Sept. 3, p. 491) on a World Health Organisation report which "is not based on first hand experience." My Department has carefully examined the report and found it to be a mixture of untruths, half-truths, and slanted information. The Minister of Health invited both the Red Cross and W.H.O. to send a team to investigate the entire mental-health set-up in South Africa during 1976. There was no reaction from W.H.O. The International Committee of the Red Cross, however, availed itself of the opportunity to "carry out an exploratory and preliminary visit to a representative sample of South African mental institutions in order to familiarize itself with the specific problems at first hand, before deciding whether or not to carry out a full-scale inspection". In an aidememoire dated May 26, 1977, addressed to the Minister of Health, the president of the International Committee of the Red Cross said: "the I.C.R.C. delegates did not find, in any of the psychiatric institutions which they visited, any patients hospitalised for other than medical reasons." You refer to a lack of published figures; these figures have been incorporated into this Department’s annual report since 1970. Your remark concerning "the absence of a single practising Black psychiatrist in South Africa" suggests that this is due to Government policy. Nothing can be further from the truth. Due to lack of interest among Black medical practitioners they cannot be coaxed into psychiatry as a specialty, despite attractive and generous scholarships and other inducements such as study leave on full pay. The statement that the great majority of African patients are treated on an involuntary basis is not entirely correct; the following statistics indicate that there has been a steady increase in the numbers treated on a voluntary basis since 1932.
Due to overcrowding in State hospitals it became essential find alternative accommodation for long-term Black patients. The solution was to use to best advantage buildings vacated by mining companies which had ceased to function. By means of tendering between private enterprise and the State these buildings were converted into hospitals. My Department has announced a multimillion-rand mental-health to
8. 9. 10. 11.
Morgan, R. W., Jain, M. Can. med. Ass. J. 1974, 111, 1067. Kessler, I. I. J. Urol. 1976, 115, 143. Simon, D., Yen, S., Cole, P. J. natn. Cancer Inst. 1975, 54, 587. Wynder, E. L., Goldsmith, R. Cancer, 1977, 40, 1246.
1223 to supply, among other things, another 7000 psychiatric beds for Blacks and 2000 for Coloured and Asian patients within the next 10 years. By means of this expansion programme, the Department hopes eventually to eliminate its use of psychiatric beds provided by private enterprise. These private hospitals are not subsidised to the tune of a third of the entire health budget of the State (over 5 million rand for 1975-76). The health budget for that year was close to R116 500 000. There is no differentiation whatsoever in professional care between White and Black patients in these private hospitals. The facilities are not luxurious, but they are certainly not degrading. To ensure high standards of care and hygiene, these institutions are regularly inspected by my Department’s medical, nursing, and health-inspectorate staff. Furthermore, there is no subcontracting of patient labour to other firms, since the patients accommodated in these private hospitals are so disturbed that they cannot be employed in the open labour market. However, in accordance with modern concepts of occupational therapy, selected patients are voluntarily employed on simple repetitive tasks such as the assembling of articles. Most of the money earned in this way is paid to the patients, and no private hospital has ever derived any financial benefit from this source.
project
Department of Health, 0001
J.
Pretoria, South Africa
DE
BEER,
Secretary for Health
**The chairman of the executive committee of the Society of
of South Africa responded in similar vein in our issue of Oct. 29. W.H.O. is entitled to use material from many sources in compiling its reports, but refusing to visit South Africa was a mistake. Dr de Beer enclosed the aide-memoire, which makes clear that the I.C.R.C. team met no restrictions on numbers or kinds of institution they could see or on the timing of visits; they were free to talk to patients and staff.ED.L.
Psychiatrists
CLOSTRIDIA AS INTESTINAL PATHOGENS
SIR,-Working in the Rowett Research Institute, Aberdeen, between 1945 and 1951 I was impressed by the role of clostridia as intestinal pathogens in sheep and pigs. When I had the chance, in 1953, to reopen the question whether clostridia might have a similar role in man, I published two papers with colleagues in Glasgow Universityl,2 which certainly proved the idea that Clostridium welchii could so operate. Many before us, of course, had had the same idea; but our findings seemed to justify the suggestion that the matter was again worth serious study. We demonstrated growth of Cl. welchii and toxin production in the gastric remnant after gastrectomy, and toxic neutralising substance in the loose stool of patients with diarrhoea from various causes. Your excellent editorial accompanying the two interesting papers in your issue of Nov. 26 could not be expected to cover all previous references to work in this area, but I am grateful to you for allowing me to remind your readers of our earlier efforts to renew interest in this subject. Knockmalloch, Newtonmore,
J.
Inverness-shire PH20 1AR
W. HOWIE
*** A Lancet editorial of Feb. 19, 1955, recalling the work of B. W. Williams in the 1920s, together with our latest effort, suggests that there may be a cyclic interest in clostridia in this context, with a periodicity of 25 years or so.-ED.L. ANAEROBES IN SPONTANEOUS PERITONITIS
SIR,-Spontaneous
bacterial
peritonitis is
a
life-threatening
infection in patients with cirrhosis and ascites. In reported 1. Howie, J. W., Duncan, I. B. R., Mackie, L. M. Lancet, 1953, i, 1018. 2. Duncan, I. B. R., Goudie, J. G., Mackie, L. M., Howie, J. W. J. Path. Bact.
1954, 67, 282.
series facultative gram-negative bacilli and streptococci consistently account for the majority of isolates while obligate anaerobes are surprisingly rare. Targan et al.’ described 2 patients with spontaneous bacterial peritonitis due to anaerobes and in their literature review found that only 6 of 126 cases had involved anaerobes. This contrasts with peritonitis associated with bowel perforation in which anaerobes are almost universal. The paucity of anaerobes in spontaneous peritonitis is paradoxical. In both favoured setiological mechanisms-transmural migration of the gastrointestinal flora and hsematogenous seeding--one would anticipate a high yield of the oxygen-sensitive bacteria which are numerically dominant in intestinal flora and account for most of the isolates recovered in transient bacterasmia. Ascites fluid is a suitable medium for anaerobes and was once a favoured broth for recovering them. Conn has explained the infrequency of anaerobes in spontaneous peritonitis as either a failure to penetrate the bowel lumen, a failure to survive transit in the bloodstream, or an inability to replicate in large volumes of ascites fluid. An alternative to these possibilities is that the environmental conditions, rather than available nutrients, are inadequate for initiation of growth. To test this hypothesis we measured the Poz of ascites fluid collected by paracentesis from 10 cirrhotic patients none of whom had intra-abdominal sepsis or spontaneous peritonitis according to clinical evaluation, cell count, or ascitic fluid culture. The aspirates were collected in closed syringes and analysed promptly in a blood-gas analyser (model 313, Instrumentation Laboratories, Watertown, Massachusetts). The mean Po, (43 mm Hg [S.E.M. 3.1], range 20-47) approximated that of mixed venous blood, suggesting that there is free exchange of gases between the systemic circulation and body fluids. In earlier experiments3 we found that 10-12% dissolved oxygen induced a complete metabolic shut-down in Bacteroides fragilis, which is common in the intestine and in intra-abdominal sepsis. Since B. fragilis is relatively oxygentolerantit is likely that oxygen has similar effects on the anaerobic species. We thus conclude that anaerobic bacteria are rare in spontaneous peritonitis because the oxygen level in the ascitic fluid stops anaerobic growth. A similar oxygen concentration is found in urine, which may explain why anaerobes are rarely found in urinary-tract infections.5 Infectious Disease Research Laboratory, Boston Veterans Administration Hospital, and Department of Medicine, Tufts University School of Medicine, Boston, Massachusetts, U.S.A.
PETER SHECKMAN ANDREW B. ONDERDONK
JOHN G. BARTLETT
MICROCOCCI AND URINARY INFECTION
SIR,-Dr Gill and Margaret Sellin (Nov. 5, p. 986) isolated strain of Micrococcus subgroup 3 (M3) from 61 specimens of fseces. They classified this isolate according to the scheme of Kloos and Schleiferas Staphylococcus cohnii, which they had not encountered before as a cause of urinary-tract infection in young women. This statement highlights the problem of the classifications proposed by Baird-Parker 7-8 and that of Kloos and Schleifer.6 We believe that Micrococcus subgroup 3 (Baird-Parker 19637) is neither a homogeneous species nor does it always correspond to S. saprophyticus of the Kloos and Schleifer scheme. one
1. Targan, S. R., Chow, A. W., Guze, L. B. Am. J. Med. 1977, 62, 397. 2. Conn, H. O., Fessel, J. M. Medicine, 1971, 50, 161. 3. Onderdonk, A. B., Johnson, J., Mayhew, J. W., Gorbach, S. L. Appl. Environ. Microbil. 1976, 31, 168. 4. Tally, F. P., Stewart, P. R., Sutter, V. L., Rosenblatt, J. E. J. clin. Microbiol. 5. 6. 7. 8.
1975,1,161. Leonhardt, K. O., Landes, R. R., N. Engl. J. Med. 1963, 269, 115. Kloos, W. E., Schleifer, K. H. J. clin. Microbiol. 1975, 1, 82. Baird-Parker, A C. J. gen. Microbiol. 1963, 30, 409. Baird-Parker, A C. Ann N.Y.Acad.Sci. 1974, 236, 7.
and it represents one of many analyses that done. Another approach to controlling for cigarette smoking and instant coffee consumption is shown in table ii in this letter. The matching has been broken since any large-sample bias thus introduced seems to be fairly negligible and in2 any case would direct the estimate of risk ratio towards unity.2 These data show that instant-coffee consumption is not confounding-neither is cigarette smoking, although it does modify the association in that lifetime non-smokers and current smokers of less than 15 cigarettes a day are not, apparently, at increased risk from artificial-sweetener use, although the estimates are based on small numbers. Your editorial stressed the difference for males and females. We recognise the dangers of arbitrarily subdividing data into categories and analysing data within such arbitrarily defined strata. However, for bladder cancer the distinction between males and females seems to us to be fundamental and not arbitrary and we decided to do this analysis by sex before we knew the results. Possible reasons for the sex discrepancy are chance, a difference between the sexes with respect to carcinogenicity (which, despite the similar finding in animals, you feel to be unlikely), or a bias which particularly affected the female controls. With respect to the latter the percentage users of artificial sweeteners among the female controls in the three areas was far less consistent than for the males (table t). Male cases used more artificial sweeteners per se but did not use more dietetic foods and beverages than male controls, whereas female cases used less artificial sweeteners, less dietetic foods, and less dietetic beverages than did female controls. Dietetic foods and beverages are comparatively new; only 1 of our subjects reported using them more than ten years before interview, whereas among those 13 subjects who indicated the time period when they used artificial sweeteners in tablet or drop form, 10 used them during or before the 1939-45 war. Thus, if artificial sweeteners are carcinogenic (and have the usual long latent period for bladder carcinogenesis) one would anticipate an increased risk associated with the use of tablets or drops but not with the use of dietetic foods or beverages. The reverse effect observed in females is much weaker, because of the smaller numbers. The pattern is, however, consistent with a group of female controls who were overweight and thus used artificial sweeteners, dietetic foods, and dietetic beverages. If the observed association between artificial sweeteners and male bladder cancer is not due to chance, then it must be: (1) real; (2) due to confounding; or (3) due to some systematic bias or error in study design and execution. We feel that table u and other analyses where we have controlled for confounding in other ways adequately cover this issue. None of these analyses indicates that the observed association between artificialsweetener use and bladder cancer in males could be due to confounding by some variable for which we have quantitative information. Neither are we aware of any possible confounding factor which could explain such an association but for which we have no data. The possibility of a systematic bias or error is harder to exclude. Nevertheless, the careful design and execution of our study, the internal consistency of the results, and the agreement between our results and those of previous investigators for variables other than artificial-sweetener use point to the lack of any such bias. Our results helps to clarify those studies which failed to show an effect on bladder-cancer mortality among diabetics. 3Further, they do not contradict the lack of association between the secular trends in bladder-cancer mortality and national patterns of artificial-sweetener consumption6,7 in view of the low attributable risk observed in our study in the general population. Our results differ primarily from those of investi-
definitive,
were
2. 3. 4.
Seigel, D. G., Greenhouse, S. W. J. chron. Dis. 1973, 26, 219. Armstrong, B., Doll, R. Br. J. prev. soc. Med. 1975, 29, 73. Armstong, B., Lee, A. J., Adelstein, A. M., Donovan, J. W., White, G. C., Rittle, S. ibid. 1976, 30, 151. 5. Kessler, I. I. J. natn. Cancer Inst. 1970, 44, 673. 6. Berbank, F., Fraumeni, Jr. J. F. Nature, 1970, 227, 296. 7. Armstrong, B., Doll, R. Br. J. prev. soc Med. 1974, 18, 233.
gators who have carried out previous case/control studies. Essentially, the major and possibly critical difference in design lies in the use of "neighbourhood" as opposed to "hospital" controls. One source of bias in hospital controls is any association between being overweight and the risk of hospital admission. In two of the four reported case/control studies’-" using hospital controls, the frequency of use of artificial sweeteners among male controls
was much higher than in our study (30%8 and 18%9). We agree that the role of artificial sweeteners in the xtiology of bladder cancer requires further study in man, but we feel that our study should not be dismissed and should be given at least equal weighting with the negative findings.
Epidemiology Unit, National Cancer Institute of Canada,
University of Toronto, Toronto, Ontario, Canada
A. B. MILLER G. R. HOWE
APARTHEID AND MENTAL HEALTH CARE
SIR,-Iam surprised that The Lancet should comment (Sept. 3, p. 491) on a World Health Organisation report which "is not based on first hand experience." My Department has carefully examined the report and found it to be a mixture of untruths, half-truths, and slanted information. The Minister of Health invited both the Red Cross and W.H.O. to send a team to investigate the entire mental-health set-up in South Africa during 1976. There was no reaction from W.H.O. The International Committee of the Red Cross, however, availed itself of the opportunity to "carry out an exploratory and preliminary visit to a representative sample of South African mental institutions in order to familiarize itself with the specific problems at first hand, before deciding whether or not to carry out a full-scale inspection". In an aidememoire dated May 26, 1977, addressed to the Minister of Health, the president of the International Committee of the Red Cross said: "the I.C.R.C. delegates did not find, in any of the psychiatric institutions which they visited, any patients hospitalised for other than medical reasons." You refer to a lack of published figures; these figures have been incorporated into this Department’s annual report since 1970. Your remark concerning "the absence of a single practising Black psychiatrist in South Africa" suggests that this is due to Government policy. Nothing can be further from the truth. Due to lack of interest among Black medical practitioners they cannot be coaxed into psychiatry as a specialty, despite attractive and generous scholarships and other inducements such as study leave on full pay. The statement that the great majority of African patients are treated on an involuntary basis is not entirely correct; the following statistics indicate that there has been a steady increase in the numbers treated on a voluntary basis since 1932.
Due to overcrowding in State hospitals it became essential find alternative accommodation for long-term Black patients. The solution was to use to best advantage buildings vacated by mining companies which had ceased to function. By means of tendering between private enterprise and the State these buildings were converted into hospitals. My Department has announced a multimillion-rand mental-health to
8. 9. 10. 11.
Morgan, R. W., Jain, M. Can. med. Ass. J. 1974, 111, 1067. Kessler, I. I. J. Urol. 1976, 115, 143. Simon, D., Yen, S., Cole, P. J. natn. Cancer Inst. 1975, 54, 587. Wynder, E. L., Goldsmith, R. Cancer, 1977, 40, 1246.
1223 to supply, among other things, another 7000 psychiatric beds for Blacks and 2000 for Coloured and Asian patients within the next 10 years. By means of this expansion programme, the Department hopes eventually to eliminate its use of psychiatric beds provided by private enterprise. These private hospitals are not subsidised to the tune of a third of the entire health budget of the State (over 5 million rand for 1975-76). The health budget for that year was close to R116 500 000. There is no differentiation whatsoever in professional care between White and Black patients in these private hospitals. The facilities are not luxurious, but they are certainly not degrading. To ensure high standards of care and hygiene, these institutions are regularly inspected by my Department’s medical, nursing, and health-inspectorate staff. Furthermore, there is no subcontracting of patient labour to other firms, since the patients accommodated in these private hospitals are so disturbed that they cannot be employed in the open labour market. However, in accordance with modern concepts of occupational therapy, selected patients are voluntarily employed on simple repetitive tasks such as the assembling of articles. Most of the money earned in this way is paid to the patients, and no private hospital has ever derived any financial benefit from this source.
project
Department of Health, 0001
J.
Pretoria, South Africa
DE
BEER,
Secretary for Health
**The chairman of the executive committee of the Society of
of South Africa responded in similar vein in our issue of Oct. 29. W.H.O. is entitled to use material from many sources in compiling its reports, but refusing to visit South Africa was a mistake. Dr de Beer enclosed the aide-memoire, which makes clear that the I.C.R.C. team met no restrictions on numbers or kinds of institution they could see or on the timing of visits; they were free to talk to patients and staff.ED.L.
Psychiatrists
CLOSTRIDIA AS INTESTINAL PATHOGENS
SIR,-Working in the Rowett Research Institute, Aberdeen, between 1945 and 1951 I was impressed by the role of clostridia as intestinal pathogens in sheep and pigs. When I had the chance, in 1953, to reopen the question whether clostridia might have a similar role in man, I published two papers with colleagues in Glasgow Universityl,2 which certainly proved the idea that Clostridium welchii could so operate. Many before us, of course, had had the same idea; but our findings seemed to justify the suggestion that the matter was again worth serious study. We demonstrated growth of Cl. welchii and toxin production in the gastric remnant after gastrectomy, and toxic neutralising substance in the loose stool of patients with diarrhoea from various causes. Your excellent editorial accompanying the two interesting papers in your issue of Nov. 26 could not be expected to cover all previous references to work in this area, but I am grateful to you for allowing me to remind your readers of our earlier efforts to renew interest in this subject. Knockmalloch, Newtonmore,
J.
Inverness-shire PH20 1AR
W. HOWIE
*** A Lancet editorial of Feb. 19, 1955, recalling the work of B. W. Williams in the 1920s, together with our latest effort, suggests that there may be a cyclic interest in clostridia in this context, with a periodicity of 25 years or so.-ED.L. ANAEROBES IN SPONTANEOUS PERITONITIS
SIR,-Spontaneous
bacterial
peritonitis is
a
life-threatening
infection in patients with cirrhosis and ascites. In reported 1. Howie, J. W., Duncan, I. B. R., Mackie, L. M. Lancet, 1953, i, 1018. 2. Duncan, I. B. R., Goudie, J. G., Mackie, L. M., Howie, J. W. J. Path. Bact.
1954, 67, 282.
series facultative gram-negative bacilli and streptococci consistently account for the majority of isolates while obligate anaerobes are surprisingly rare. Targan et al.’ described 2 patients with spontaneous bacterial peritonitis due to anaerobes and in their literature review found that only 6 of 126 cases had involved anaerobes. This contrasts with peritonitis associated with bowel perforation in which anaerobes are almost universal. The paucity of anaerobes in spontaneous peritonitis is paradoxical. In both favoured setiological mechanisms-transmural migration of the gastrointestinal flora and hsematogenous seeding--one would anticipate a high yield of the oxygen-sensitive bacteria which are numerically dominant in intestinal flora and account for most of the isolates recovered in transient bacterasmia. Ascites fluid is a suitable medium for anaerobes and was once a favoured broth for recovering them. Conn has explained the infrequency of anaerobes in spontaneous peritonitis as either a failure to penetrate the bowel lumen, a failure to survive transit in the bloodstream, or an inability to replicate in large volumes of ascites fluid. An alternative to these possibilities is that the environmental conditions, rather than available nutrients, are inadequate for initiation of growth. To test this hypothesis we measured the Poz of ascites fluid collected by paracentesis from 10 cirrhotic patients none of whom had intra-abdominal sepsis or spontaneous peritonitis according to clinical evaluation, cell count, or ascitic fluid culture. The aspirates were collected in closed syringes and analysed promptly in a blood-gas analyser (model 313, Instrumentation Laboratories, Watertown, Massachusetts). The mean Po, (43 mm Hg [S.E.M. 3.1], range 20-47) approximated that of mixed venous blood, suggesting that there is free exchange of gases between the systemic circulation and body fluids. In earlier experiments3 we found that 10-12% dissolved oxygen induced a complete metabolic shut-down in Bacteroides fragilis, which is common in the intestine and in intra-abdominal sepsis. Since B. fragilis is relatively oxygentolerantit is likely that oxygen has similar effects on the anaerobic species. We thus conclude that anaerobic bacteria are rare in spontaneous peritonitis because the oxygen level in the ascitic fluid stops anaerobic growth. A similar oxygen concentration is found in urine, which may explain why anaerobes are rarely found in urinary-tract infections.5 Infectious Disease Research Laboratory, Boston Veterans Administration Hospital, and Department of Medicine, Tufts University School of Medicine, Boston, Massachusetts, U.S.A.
PETER SHECKMAN ANDREW B. ONDERDONK
JOHN G. BARTLETT
MICROCOCCI AND URINARY INFECTION
SIR,-Dr Gill and Margaret Sellin (Nov. 5, p. 986) isolated strain of Micrococcus subgroup 3 (M3) from 61 specimens of fseces. They classified this isolate according to the scheme of Kloos and Schleiferas Staphylococcus cohnii, which they had not encountered before as a cause of urinary-tract infection in young women. This statement highlights the problem of the classifications proposed by Baird-Parker 7-8 and that of Kloos and Schleifer.6 We believe that Micrococcus subgroup 3 (Baird-Parker 19637) is neither a homogeneous species nor does it always correspond to S. saprophyticus of the Kloos and Schleifer scheme. one
1. Targan, S. R., Chow, A. W., Guze, L. B. Am. J. Med. 1977, 62, 397. 2. Conn, H. O., Fessel, J. M. Medicine, 1971, 50, 161. 3. Onderdonk, A. B., Johnson, J., Mayhew, J. W., Gorbach, S. L. Appl. Environ. Microbil. 1976, 31, 168. 4. Tally, F. P., Stewart, P. R., Sutter, V. L., Rosenblatt, J. E. J. clin. Microbiol. 5. 6. 7. 8.
1975,1,161. Leonhardt, K. O., Landes, R. R., N. Engl. J. Med. 1963, 269, 115. Kloos, W. E., Schleifer, K. H. J. clin. Microbiol. 1975, 1, 82. Baird-Parker, A C. J. gen. Microbiol. 1963, 30, 409. Baird-Parker, A C. Ann N.Y.Acad.Sci. 1974, 236, 7.
