932
The child remained febrile,
drowsy, and irritable and penicillin. The chloramphenicol despite treatment was then changed to cefotaxime 200 mg/kg daily, and within 24 h the child became afebrile, alert, and less irritable. He was discharged after 10 days. At follow-up bilateral deafness was noted but we do not know if this might have been prevented had cefotaxime been given from the start. 0 125
mg/1).
treatment for 48 h with
Department of Paediatrics, North Tyneside General Hospital
R. E. GEORGE U. K. WARIYAR
Department of Microbiology, North Tyneside General Hospital, North Shields NE29 8NH, UK
G. GOPAL RAO
Chemoprophylaxis for infective endocarditis SIR,-I read with unease your Feb 29 editorial on prophylaxis for infective endocarditis. The paper by Dr van der Meer and colleagues (Jan 18, p 135) that it discussed approached the lack of a controlled assessment of prophylaxis in an ingenious epidemiological fashion. As so often with such analyses, however, I was uncertain whether the point had been proved. For example, the editorial and the article stress that only a small proportion of endocarditis cases are due to recent medical/dental procedures (endpoint, endocarditis; procedure, rare cause of endpoint ; ergo, do not "treat" procedure). Only a small proportion of deaths are due to lobar pneumonia, but this has not hindered the use of antibiotics in such cases (endpoint, death; lobar pneumonia, rare cause of endpoint; ergo, do not treat pneumonia). The predictable fmding that many procedures done without antibiotic cover do not precipitate infective endocarditis is simply analogous with the number of patients with lobar pneumonia who would survive without antibiotics. In any case, prophylaxis is not meant to prevent disease every time. One might argue that the prophylactic effect of antibiotics is less well established than their efficacy in pneumonia. However, van der Meer et al themselves produce a best estimate of "protective effect" of 49%. No confidence limits are given, but since this figure fails to achieve statistical significance, one must assume the lower limit is below zero. Where, then, is the upper limit of possible effect? Prophylaxis might "at best have prevented endocarditis in 20 patients". This figure discounts those already prevented by 26% compliance. Besides, is 20 cases too few to justify the prophylactic use of a simple antibiotic? Cost benefit analysis is suggested, but van der Meer et al have attempted none. The very low price of ampicillin is unlikely to enhance their argument. Infective endocarditis is not a trivial disease. Your editorial is perhaps correct in calling for a controlled trial, but it is worrying that, in the interim, clinicians may be tempted to abandon current practice on the basis of a tangential study that simply failed to prove
impressive efficacy. Southern General Hospital, Glasgow G51 4TF, UK
JOHN LARKIN
Chemoprophylaxis for skin surgery SIR,-Skin surgery is increasing in the UK, through a combination of greater prevalence of non-melanoma skin cancer1 and encouragement for general practitioners to do surgical procedures.2 The Endocarditis Working Party provides no specific guidelines on the need for antibiotic prophylaxis in skin surgery,3 but "hope" that the risk of bacteraemia in this setting is too low to warrant intervention (personal communication). Informal discussion and unsubstantiated recommendations" suggest that dermatologists often do prescribe prophylactic antibiotics for skin surgery in those whose endocardium is damaged or rendered defective by acquired or congenital heart disease. We are investigating the risk of bacteraemia from surgery done on non-infected skin under local anaesthesia in adult, nonimmunocompromised, day-case patients who have not received antibiotics within the previous week. Among the first 60 patients recruited and venesected immediately before and after the skin procedure, no bacteraemia has been identified by Bactec System aerobic and anaerobic culture (95% CI 0-5-96%). The American
Heart Association suggests that prophylactic antibiotics are indicated only for those with prosthetic valves in procedures associated with a risk of bacteraemia of greater than 5%.5 Coagulase-negative staphylococci are the predominant skin organisms present on 69% of skin lesions4 and represent the most likely cause of bacteraemia. We have reviewed the antimicrobial sensitivities of our 115 most recent isolates of this organism and the only antibiotic to which they are all sensitive is vancomycin, Vancomycin must be infused over an hour and carries a recognised
morbidity.6 The low incidence of bacteraemia and potential morbidity associated with the appropriate antibiotic suggest that skin surgery does not warrant prophylactic antibiotics to prevent bacterial endocarditis. ANDREW J. CARMICHAEL Departments of Dermatology PETER J. A. HOLT and Medical Microbiology, PAUL FLANAGAN University Hospital of Wales, Cardiff CF4 4XW, UK BRIAN I. DUERDEN 1. Roberts DL Incidence of non-melanoma skin cancer in West
2. 3. 4
5. 6.
Glamorgan, South
Wales. Br JDermatol 1990; 122: 399-403. Whimst WF, Leonard RA. Surgical pathology and general practice. Br Med J 1991; 303: 1149-50. Endocarditis Working Party of the British Society for Antimicrobial Chemotherapy. Antibiotic prophylaxis of infective endocarditis. Lancet 1990; 335: 88-89. Maurice PDL, Parker S, Azadian BS, Cream JJ. Minor skin surgery. Are prophylactic antibiotics ever needed for curettage? Acta Derm Venereol (Stockh) 1991; 71: 267-68. Shulman ST, Amren DP, Bisno AL, et al. Prevention of bacterial endocarditis. Am J Dis Child 1985; 139: 232-35. Garretts JC, Petene JD. Vancomycin and the "red man’s syndrome". N Engl J Med
1985; 312: 245
Subzonal insemination SIR,-Dr Krzyminska and colleagues’ letter (Feb 8, p 375) on microinsemination presents "more encouraging" data based on semen characteristics "well below" WHO guidelines. Those guidelines are no longer appropriate for assisted conception procedures, especially micro-scale fertilisation. Successful in-vitro fertilisation (IVF) is achieved routinely with single, double, or triple defects in the spermatozoa at levels well below those guidelines. With micro-drop insemination (a variation of IVF) and modem sperm preparation methods many units achieve fertilisation with spermatozoa considered unacceptable for standard IVF protocols. 60% of Krzyminska’s patients were considered unsuitable for conventional IVF, but the severity of unsuitability was not presented. Data on subzonal insemination (SUZI), and all microscale-assisted fertilisation techniques, should be given on the basis of actual values for the ejaculate used for the preparation of spermatozoa.! Using this approach, we have more useful criteria based on total motile sperm count, (TMC; see footnote to table). This yields a clearer demarcation for the expected fertilisation rate per oocyte (8%, 25%, 21%, 20% and 30%, for groups 1-5, respectively), and per patient (29%, 51%, 46%, 42%, 57%) with SUZI.’ The only significant difference arises with group 1, for both oocytes and patients. We are shortly to publish a detailed evaluation on 225 patients’ in which 12 clinical pregnancies were established and 8 healthy babies delivered, and the latest figures relate to 287 cycles and 20 babies delivered. The results were clearly related to the specific quality of the semen.’1 40% of patients in Krzyminska’s study had failed IVF previously. The frequency of failure and the degree of severity of the seminal defects cannot be assessed from their data. However, previous failure to achieve fertilisation one or more times does not preclude success in subsequent cycles.2 Just as previous failures with IVF cannot act alone as a control for a different subsequent procedure, nor can spermatozoa presumed unacceptable for IVF and used only in SUZI (except in cases of total immotility or globozoospermia, for example) be used as sole control for a comparison of SUZI versus IVF. Only oocytes from the same cohort where half are subject to SUZI and the remainder to IVF can be considered a valid control. Ng et aP found no significant difference when IVF was used as a control for SUZI except for the group with the severest sperm density. In this group, no IVF
The child remained febrile,
drowsy, and irritable and penicillin. The chloramphenicol despite treatment was then changed to cefotaxime 200 mg/kg daily, and within 24 h the child became afebrile, alert, and less irritable. He was discharged after 10 days. At follow-up bilateral deafness was noted but we do not know if this might have been prevented had cefotaxime been given from the start. 0 125
mg/1).
treatment for 48 h with
Department of Paediatrics, North Tyneside General Hospital
R. E. GEORGE U. K. WARIYAR
Department of Microbiology, North Tyneside General Hospital, North Shields NE29 8NH, UK
G. GOPAL RAO
Chemoprophylaxis for infective endocarditis SIR,-I read with unease your Feb 29 editorial on prophylaxis for infective endocarditis. The paper by Dr van der Meer and colleagues (Jan 18, p 135) that it discussed approached the lack of a controlled assessment of prophylaxis in an ingenious epidemiological fashion. As so often with such analyses, however, I was uncertain whether the point had been proved. For example, the editorial and the article stress that only a small proportion of endocarditis cases are due to recent medical/dental procedures (endpoint, endocarditis; procedure, rare cause of endpoint ; ergo, do not "treat" procedure). Only a small proportion of deaths are due to lobar pneumonia, but this has not hindered the use of antibiotics in such cases (endpoint, death; lobar pneumonia, rare cause of endpoint; ergo, do not treat pneumonia). The predictable fmding that many procedures done without antibiotic cover do not precipitate infective endocarditis is simply analogous with the number of patients with lobar pneumonia who would survive without antibiotics. In any case, prophylaxis is not meant to prevent disease every time. One might argue that the prophylactic effect of antibiotics is less well established than their efficacy in pneumonia. However, van der Meer et al themselves produce a best estimate of "protective effect" of 49%. No confidence limits are given, but since this figure fails to achieve statistical significance, one must assume the lower limit is below zero. Where, then, is the upper limit of possible effect? Prophylaxis might "at best have prevented endocarditis in 20 patients". This figure discounts those already prevented by 26% compliance. Besides, is 20 cases too few to justify the prophylactic use of a simple antibiotic? Cost benefit analysis is suggested, but van der Meer et al have attempted none. The very low price of ampicillin is unlikely to enhance their argument. Infective endocarditis is not a trivial disease. Your editorial is perhaps correct in calling for a controlled trial, but it is worrying that, in the interim, clinicians may be tempted to abandon current practice on the basis of a tangential study that simply failed to prove
impressive efficacy. Southern General Hospital, Glasgow G51 4TF, UK
JOHN LARKIN
Chemoprophylaxis for skin surgery SIR,-Skin surgery is increasing in the UK, through a combination of greater prevalence of non-melanoma skin cancer1 and encouragement for general practitioners to do surgical procedures.2 The Endocarditis Working Party provides no specific guidelines on the need for antibiotic prophylaxis in skin surgery,3 but "hope" that the risk of bacteraemia in this setting is too low to warrant intervention (personal communication). Informal discussion and unsubstantiated recommendations" suggest that dermatologists often do prescribe prophylactic antibiotics for skin surgery in those whose endocardium is damaged or rendered defective by acquired or congenital heart disease. We are investigating the risk of bacteraemia from surgery done on non-infected skin under local anaesthesia in adult, nonimmunocompromised, day-case patients who have not received antibiotics within the previous week. Among the first 60 patients recruited and venesected immediately before and after the skin procedure, no bacteraemia has been identified by Bactec System aerobic and anaerobic culture (95% CI 0-5-96%). The American
Heart Association suggests that prophylactic antibiotics are indicated only for those with prosthetic valves in procedures associated with a risk of bacteraemia of greater than 5%.5 Coagulase-negative staphylococci are the predominant skin organisms present on 69% of skin lesions4 and represent the most likely cause of bacteraemia. We have reviewed the antimicrobial sensitivities of our 115 most recent isolates of this organism and the only antibiotic to which they are all sensitive is vancomycin, Vancomycin must be infused over an hour and carries a recognised
morbidity.6 The low incidence of bacteraemia and potential morbidity associated with the appropriate antibiotic suggest that skin surgery does not warrant prophylactic antibiotics to prevent bacterial endocarditis. ANDREW J. CARMICHAEL Departments of Dermatology PETER J. A. HOLT and Medical Microbiology, PAUL FLANAGAN University Hospital of Wales, Cardiff CF4 4XW, UK BRIAN I. DUERDEN 1. Roberts DL Incidence of non-melanoma skin cancer in West
2. 3. 4
5. 6.
Glamorgan, South
Wales. Br JDermatol 1990; 122: 399-403. Whimst WF, Leonard RA. Surgical pathology and general practice. Br Med J 1991; 303: 1149-50. Endocarditis Working Party of the British Society for Antimicrobial Chemotherapy. Antibiotic prophylaxis of infective endocarditis. Lancet 1990; 335: 88-89. Maurice PDL, Parker S, Azadian BS, Cream JJ. Minor skin surgery. Are prophylactic antibiotics ever needed for curettage? Acta Derm Venereol (Stockh) 1991; 71: 267-68. Shulman ST, Amren DP, Bisno AL, et al. Prevention of bacterial endocarditis. Am J Dis Child 1985; 139: 232-35. Garretts JC, Petene JD. Vancomycin and the "red man’s syndrome". N Engl J Med
1985; 312: 245
Subzonal insemination SIR,-Dr Krzyminska and colleagues’ letter (Feb 8, p 375) on microinsemination presents "more encouraging" data based on semen characteristics "well below" WHO guidelines. Those guidelines are no longer appropriate for assisted conception procedures, especially micro-scale fertilisation. Successful in-vitro fertilisation (IVF) is achieved routinely with single, double, or triple defects in the spermatozoa at levels well below those guidelines. With micro-drop insemination (a variation of IVF) and modem sperm preparation methods many units achieve fertilisation with spermatozoa considered unacceptable for standard IVF protocols. 60% of Krzyminska’s patients were considered unsuitable for conventional IVF, but the severity of unsuitability was not presented. Data on subzonal insemination (SUZI), and all microscale-assisted fertilisation techniques, should be given on the basis of actual values for the ejaculate used for the preparation of spermatozoa.! Using this approach, we have more useful criteria based on total motile sperm count, (TMC; see footnote to table). This yields a clearer demarcation for the expected fertilisation rate per oocyte (8%, 25%, 21%, 20% and 30%, for groups 1-5, respectively), and per patient (29%, 51%, 46%, 42%, 57%) with SUZI.’ The only significant difference arises with group 1, for both oocytes and patients. We are shortly to publish a detailed evaluation on 225 patients’ in which 12 clinical pregnancies were established and 8 healthy babies delivered, and the latest figures relate to 287 cycles and 20 babies delivered. The results were clearly related to the specific quality of the semen.’1 40% of patients in Krzyminska’s study had failed IVF previously. The frequency of failure and the degree of severity of the seminal defects cannot be assessed from their data. However, previous failure to achieve fertilisation one or more times does not preclude success in subsequent cycles.2 Just as previous failures with IVF cannot act alone as a control for a different subsequent procedure, nor can spermatozoa presumed unacceptable for IVF and used only in SUZI (except in cases of total immotility or globozoospermia, for example) be used as sole control for a comparison of SUZI versus IVF. Only oocytes from the same cohort where half are subject to SUZI and the remainder to IVF can be considered a valid control. Ng et aP found no significant difference when IVF was used as a control for SUZI except for the group with the severest sperm density. In this group, no IVF
