CORRESPONDENCE * All letters must be typed with double spacing and signed by all authors. * No letter should be more than 400 words. * For letters on scientific subjects we normally reserve our correspondence columns for those relating to issues discussed recently (within six weeks) in the BMJ. * We do not routinely acknowledge letters. Please send a stamped addressed envelope ifyou would like an acknowledgment. * Because we receive many more letters than we can publish we may shorten those we do print, particularly when we receive several on the same subject.

AIDS stigma in insurance market SIR,-Underwriters and insurance doctors must be concerned about the unfortunate experience (not at the hands of my own office) of Mr David Morgan following his declaration of a previous HIV test.' There is no stigma attached to having had such a test in the past, and the commonest reason in insurance medicine for requesting HIV testing is the size of the proposed policy. Insurance companies are obliged to adopt prudent underwriting practices in line with the mortality assumptions made in their premium rates in order to protect the funds of their policyholders. Most companies, my own included, maintain a list of senior and experienced doctors prepared to undertake examinations on their behalf. The client is asked to make the appointment in the usual way, and if HIV testing is required a detailed written explanation is given in advance together with the wording of the consent form. The examiner should, of course, be prepared to offer further counselling, but in the course of undertaking many of these examinations I have never been asked any additional questions about the test. Before the HIV test is done the client is asked to name a doctor who can be notified in the event of the result being positive. Some prefer that it should

be their usual family or company doctor, and their wishes are respected. There may be good reasons for not notifying patients of the results of negative tests-divorce almost resulted when one unsuspecting wife unaware of the application for insurance found a letter in her husband's post to say he was HIV negative. I cannot, however, imagine any insurance company refusing a request for the patient to be informed of the result of a test that proved negative; if tests proved positive the nominated doctor would be asked to deal with the matter. If a proposal for insurance is refused the company will notify the reason for this to the general practitioner or other nominated doctor on request. If, bearing in mind the current knowledge of HIV infection, any offer of insurance is made it can be assumed that the result must have been negative. David Morgan is right to point out his examiner's lack of proper professional concern, but he should not condemn the insurers, who try hard to ascertain the risk of any proposal in a fair and reasonable manner. GEOFFREY H ROBB Friends' Provident Life Office, Dorking, Surrey RH4 IQA I Morgan D. AIDS stigma in insurance market. Br Med 1989;299:1536. (16 December.)

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Selective decontamination of the digestive tract SIR,-Dr P J Sanderson states that selective decontamination of the digestive tract implies the widespread use of antibiotics in the intensive care unit, where the risk of microbial resistance is already high.' This is based on a false premise as selective decontamination is not being compared with a situation in which no antibiotics are used; in fact, in a general intensive care unit large quantities of therapeutic parenteral antibiotics are utilised under traditional infection management protocols. Selective decontamination of the digestive tract has been shown to reduce significantly the requirement for parenteral antibiotics,2 and this may reduce the selection pressure for resistance. As Dr Sanderson points out, despite careful surveillance no increase in resistance has been seen despite extensive experience with selective decontamination in many units. He raises doubts about the relative importance of the oropharyngeal, gastric, and systemic components of the selective decontamination regimen. In particular he states that the contribution of the systemic antibiotic is not clear and its danger is the greatest. What danger is he referring to? He does not mention the publication by the Groningen group examining the historical background to the introduction of the full regimen.' In a prospective open trial it showed no benefit from gastrointestinal

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decontamination alone in comparison with a control group. When oropharyngeal and gastrointestinal decontamination were used together the incidence of late infections was reduced significantly but the incidence of early infections was not affected. A third group received oropharyngeal and gastrointestinal decontamination supplemented with systemic cefotaxime, and only then were excellent results achieved.4 Dr Sanderson says that Unertl et al5 obtained comparable results without using a systemic agent but does not mention that in this study all patients showing signs of infection at the time of admission were excluded-removing one of the indications for utilising a systemic agent. From the above I would conclude that oropharyngeal decontamination may be the most important factor in preventing nosocomial pneumonia. Gastrointestinal decontamination should not be excluded as to do so would leave a pool of abnormal Gram negative colonisation in the lower gastrointestinal tract, with an associated risk of developing microbial resistance. In addition, we who have carried out trials of selective decontamination of the digestive tract believe that there is a strong case for including a systemic agent in addition to the drugs for selective decontamination. The Glasgow study referred to by Dr Sanderson2 included all the

patients admitted to intensive care units, including a high percentage who were infected on admission. In this situation the systemic cefotaxime acts as a treatment and not merely as prophylaxis. Without the regimen an alternative agent would have to be used. The use of a systemic agent as a supplement to selective decontamination of the digestive tract is entirely rational, as reviewed by Alcock'; it treats infections either present before or incubating at the time of admission and provides supplementary prophylaxis during the establishment of selective decontamination, which takes three to four days. Dr Sanderson quotes references from five centres that have published results of selective decontamination of the digestive tract and concludes that its value in intensive care is "not yet proved." I have recently reviewed 10 publications, all from different centres, all of which report a significant reduction in infection rates7; and as selective decontamination was introduced in an attempt to decrease the infection rate in intensive care units I would contend that the case is indeed proved. I dispute that a regimen introduced to decrease infection should be judged by a change in mortality. Moreover, the mortality results are less negative than currently supposed. Among the 10 trials recently reviewed, significant reductions in infection were reported in two (C Guillaume et al, international conference on antimicrobial chemotherapy, Houston, 1989)7 and two others reported a significant reduction in mortality related to infection.5 As mentioned in the article, the Glasgow study2 provided evidence of a clear mortality benefit for patients with trauma and also suggested a potential improvement in mortality in long stay patients. Dr Sanderson's contention that the case for selective decontamination of the digestive tract is not proved is unjustified, but I would agree that its precise role in intensive care units is not yet fully evaluated. G RAMSAY

Department of Surgery, Western Infirmary, Glasgow G Il 6NT I Sanderson PJ. Selective decontamination of thc digestive tract. BrMedj 1989;299: 1413-4. (9 December.) 2 Ledingham IM, Alcock SR, Eastaway Al, McDonald JC,

MacKay IC, Ramsay G. Triple regimen of selective decontamination of the digestive tract, systemic cefotaxime, and microbiological surveillance for prevention of acquired infection in intensive care. Lancet 1988;i:785-90. 3 Stoutenbeek CP, van Saene HKF, Miranda DR, Zandstra DF, Langrehr D. The effect of oropharyngeal decontamination using topical non-absorbable antibiotics on the incidence of nosocomial respiratory tract infections in multiple trauma patients. J Trauma 1987;27:357-64. 4 Stoutenbeek CP, van Saene HKF, Miranda DR, Zandstra DF. The effect of selective decontamination of the digestive tract on colonisation and infection rate in multiple trauma patients. Intensive Care Med 1984;10: 185-92. 5 Unertl K, Ruckdeschel G, Selbmann HK, et al. Prevention of colonisation and respiratory infections in long term ventilated patients by local antimicrobial prophylaxis. Intensive Care Med 1987;13: 106-8.

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6 Alcock SR. Use of a short term parenteral antibiotic as a supplement to SDD. In: san Saene HKF, Stoutenbeek Cl', Lawin P, Ledingham IM, eds. Infection control by selective decontamination. Berlin: Springcr Verlag, 1989:102-8. 7 Svdow hi, Burchardi T, Fraatz T, et al. Prevention of nocosomial pneumonia in mechanically ventilated patients in a respiratory intensive care unit. Intensive Care Med 1988;14:S3 10. 8 Kerver AJH, Rommes JH, Mevissen-Verhage EAE, et al. Prevention of colonisation and infection in critically ill patients: a prospective randomised study. Crit Care Med 1988;16: 1087-93.

SIR,-Though I agree with Dr P J Sanderson' that the effects of selective decontamination of the digestive tract are not yet proved, I believe that his rather negative views of the technique are not substantiated by the available evidence, which indicates that the technique shows considerable promise. Stoutenbeek et al showed a striking reduction in the incidence of colonisation and infection in patients with multiple trauma.2 Colonisation of the digestive tract in the control group reached 100% by day 21, whereas in the selective decontamination group it had fallen to zero. The incidence of infection was reduced from 86% to 14% in the treated patients. Another study by the same authors showed a reduction in the incidence of superinfection in patients with trauma from 24% to 3% with selective decontamination.' The technique was also found to cause an appreciable improvement in the intensive care environment: sinks and working surfaces showed a substantial decrease in colonisation. Ledingham et al4 also showed a considerable reduction in secondary infection acquired in the intensive care unit from 24% in the control group to 10% in the patients receiving the regimen, and the authors carefully tried to distinguish patients in whom the infections were likely to have been incubating before admission to the intensive care unit. This work also showed that although the overall mortality was the same in the two groups, there was a significant reduction in mortality in patients with major trauma, six out of 23 control patients dying compared with no deaths in the selective decontamination group. Mortality was also substantially reduced in patients admitted to the intensive care unit for more than seven days and in those with mid-range APACHE II scores; these two groups of patients have been well documented as being at risk of infection, and infection has been shown to increase their mortality. Further evidence justifying the more widespread use of this technique has come from Miranda et al, who found that using the technique saved them about $900 000 a year on their intensive care unit budget, which they attributed to shorter hospital stays as a result of less infection and a decreased use of disposables and drugs, particularly antibiotics.' Dr Sanderson's concern about the likely development of resistance to the systemic antibiotic cefotaxime, though justified, was not confirmed by Stoutenbeek et al, who showed no increase in the incidence of resistance to the drug over three years.' In conclusion, I agree that selective decontamination requires further evaluation, in particular with reference to the specific contributions made by cefotaxime and the selective decontamination components and to whether the regimen should be used for all patients in intensive care units or for only certain specific groups, but I suggest that the technique has shown considerable benefits; I agree with Ledingham et al, who said that "there is now a considerable body of evidence to justify the more widespread use of the technique in intensive care." NIGEL COAD

Department of Anacsthetics, University Hospital, Nottingham NG7 2UH I Sanderson PJ. Selective decontamination of the digestive tract. BrMedJ 1989;299:1413-4. (9 December.)

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2 Stoutenheek CP, san Saene HKF, Miranda DR, Zandstra DF. The effect of selective decontamination of the digestive tract on colonisation and infection rates in multiple trauma patients. Intensive Care Med 1984;10: 185-92. 3 Stoutenheek CP, van Saene HKF, Miranda DR, Zandstra DF, Binnendijk DR. The prevention of superinfection in multiple trauma patients. Jr Antimicrob Chemother 1984;14(suppl B): 203-11. 4 Ledingham IM, Alcock SR, Eastawav AT, MicDonald JC, McKay IC, Ramsay G. Triple regime of selective decontamination of the digestive tract, systemic cefotaxime and microbiological surveillance for prevention of acquired infection in intensive care. Lancet 1988;i:785-90. 5 Mtiranda DR, van Saene HKF, Stoutenbeek CP, Zandstra DF. Environment and cost in the surgical intensive care unit. The implication of selective decontamination of the digestive tract. Acta Anaesthesiol Beig 1983;34:223-32. 6 Stoutenbeek CP, van Saene HKF, Miranda DP, Zandstra DF, Langrehr D. The emergence of resistance against prophylactically used antibiotics is prevented by selective decontamination of the digestive tract. In: Ishigami J, ed. Proceedings oJ the fourteenth international congress of chemotherapv. Kvoto, Japan: University of Tokyo Press, 1985:15-106.

SIR,-In his recent editorial on selective decontamination of the digestive tract as a means of preventing infection in intensive care units Dr P J Sanderson was highly selective in referring to published work'; there is a much wider body of evidence to support the role of selective decontamination as a valuable prophylactic regimen in the intensive care unit, which includes studies from centres in the United Kingdom,2 continental Europe,' and the United States (F R Cockerill et al, Interscience congress on antimicrobial agents and chemotherapy, Houston, 1989). The question of bacterial resistance to the enteral and systemic components of selective decontamination, rightly a preoccupation of microbiologists and others concerned with patient management in intensive care units, was recently reviewed by Alcock and Cole.4 They concluded that there is no convincing evidence of problems of drug resistance arising from the prophylactic use of selective decontamination combined with cefotaxime in a medicosurgical intensive care unit and that this contrasts with the strong evidence that this regimen is effective in preventing the major, previously intractable (and expensive) problem of patients acquiring pneumonia in intensive care units. Dr Sanderson questions the role of systemic prophylaxis with cefotaxime as a component of the selective decontamination regimen. Recently Alcock addressed this subject, pointing out that the systemic antibiotic has a dual role: firstly, in treating infection (overt or subclinical) that is present before admission to the intensive care unit and, secondly, as supplementary prophylaxis during the establishment of selective decontamination.5 That systemic prophylaxis was clearly a necessary component was shown by the Groningen group in its original publication.6 A substantial reduction in the infection acquired in the intensive care unit could be achieved only by coupling selective decontamination with systemic cefotaxime for the first few days in the unit. Indeed, Ledingham et al2 have chosen to use the acronym SPEAR (selective parenteral and enteral antisepsis reginen) rather than SDD to emphasise the essential contribution of the parenteral component of the regimen. Finally, we question Dr Sanderson's statement that the systemic antibiotic's danger is the greatest. If he implies that systemic cefotaxime is dangerous because it can lead to bacterial resistance to selective decontamination then he is contradicting his former assertion that this has not been found. If inherent toxicity is the implied danger then he ignores the extensive experience world wide that has shown cefotaxime to be a well tolerated antibiotic. 9 It is this feature of the antibiotic that, along with others, led to the original selection of cefotaxime by the Groningen workers. '° D R THOMAS D S COLE

Roussel Laboratories, Uxbridge, Middlesex UB9 5HI'

1 Sanderson PJ. Selective decontamination of the digestive tract. Br MledJ 1989;299: 1413-4. (9 December.) 2 Ledingham IM, Alcock SR, Eastaway AT, McDonald JC, MacKay IC, Ramsay G. Triple regimen of selective decontamination of the digestive tract, systemic cefotaxime, and microbiological surveillance for prevention of acquired infection in intensive care. Lancet 1988;i:785-90. 3 van Saene HKF, Stoutenbeek CP, Lawin P, Ledingham IM, eds. Infection control by selective decontamination. Berlin: Springer Verlag, 1989:115-26. 4 Alcock SR, Cole DS. Selective decontamination of the digestive tract (SDD), ICU-acquired pneumonia and selection of antibiotic-resistant bacteria. J Hosp Infect (in press). 5 Alcock SR. Use of a short term parenteral antibiotic as a supplement to SDD. In: van Saene HKF, Stoutenbeek CP, Lawin P, Ledingham IM, eds. Infection control by selective decontamination. Berlin: Springer Verlag, 1989:102-8. 6 Stoutenbeek CP, van Saene HKF, Miranda DR, Zandstra DF. A new technique of infection prevention in the intensive care unit by selective decontamination of the digestive tract. Acta Anaesthesiol Belg 1983:3:209-2 1. 7 Smith CR. Cefotaxime and cephalosporins: adverse reactions in perspective. Rev Infect Dis 1982;4(suppl):S481-8. 8 Carmine AA, Brogden RN, Heal RC, Speight TM, Avery GS. Cefotaxime: a review of its antibacterial activity, pharmacological properties and therapeutic use. )rugs 1983;25:223-89. 9 Parker RH, Park S-Y. Safety of cefotaxime and other new B-lactam antibiotics. J Antimicrob Chemother 1984;14(suppl B):331-5. 10 Stoutenbeek CP, van Saene HKF, Miranda DR, Zandstra DF, Binnendijk B. The prevention of superinfection in multiple trauma patients. J Antimicrob Chemother 1984;14(suppl B): 203-11.

AUTHOR'S REPLY,-Dr C Ramsay says that the implication of more widespread use of antibiotics under selective decontamination of the digestive tract is false; however, more individual patients would receive antibiotics under this regimen than if infections were treated as they arose. He is incorrect in stating that I do not mention the publication by the Groningen group, which gives the historical background to the introduction to the full regimen: this paper is reference 12 in my article. Regarding the role of the systemic agent cefotaxime, Stoutenbeek et al compared a group of 25 patients receiving both oropharyngeal and gastrointestinal decontamination with a group of 63 patients receiving oropharyngeal and gastrointestinal decontamination plus systemic cefotaxime.' There were no secondary or late respiratory tract infections in either of these groups, although such infections did occur in a group receiving only gastrointestinal decontamination. It is misleading therefore to say that with the addition of systemic cefotaxime "only then were excellent results achieved" either from these results or from those of Stoutenbeek et al when comparing only the full selective decontamination regimen with controls.2 Selective decontamination is aimed at preventing infection and Unertl et al were logical in excluding patients from their study who showed signs of infection on admission; such infection would in any case be treated, and cefotaxime may or may not be appropriate in all cases. Dr Ramsay writes that two of the 10 trials he reviewed reported a significant reduction in mortality related to infection; Unertl et al reported clinical sepsis as a cause of death in one of 20 control patients compared with none of 19 patients receiving selective decontamination,' and Kerver et al reported death due to an acquired infection in eight of 47 control patients compared with two of 49 patients receiving selective decontamination (p

Selective decontamination of the digestive tract.

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