- Email: [email protected]
Clostridium difficile and chlorine-releasing disinfectants
Correspondence
provide direct data on the association between peripheral vascular disease and venous thromboembolism. To address this issue, we extended our analysis of myocardial infarction and stroke to an analysis of a hospital diagnosis of peripheral arterial disease in the study cohorts (25 199 patients with deep venous thrombosis, 16 925 patients with pulmonary embolism, and 163 566 population controls). The risk estimates are provided in the table and were similar to those for myocardial infarction and stroke and are thus consistent with our conclusion that common risk factors or pathways are most likely to be responsible for the association. Meier suggests that patent foramen ovale could be a mediator for the association. The frequency of a recorded diagnosis of patent foramen ovale in our cohorts was 0·02% in patients with venous thrombosis, 0·06% in patients with pulmonary embolism, and 0·02% in population controls. Although patent foramen ovale might be under-reported in the registry, and might even be clinically unrecognised, it is unlikely that a condition with such a low prevalence could be responsible for the associations we saw. We declare that we have no conflict of interest.
*Henrik Toft Sørensen, Erzsebet Horvath-Puho, Lars Pedersen, John A Baron, Paolo Prandoni [email protected] Department of Clinical Epidemiology, Aarhus University Hospital, 8000 Aarhus C, Denmark (HTS, EHP, LP); Department of Epidemiology, Boston University School of Public Health, Boston, MA, USA (HTS); Departments of Medicine and Community and Family Medicine, Dartmouth Medical School, Hanover, NH, USA (JB); and Department of Medical and Surgical Sciences, Thromboembolism Unit, University of Padua, Padua, Italy (PP)
Clostridium difficile and chlorine-releasing disinfectants In a Correspondence letter (Dec 22, p 2098),1 Norman Simmons extrapolates in-vitro research findings in relation to Clostridium difficile spores2 to suggest that “deep cleaning” of hospitals could be harmful. We believe this is misleading. The study quoted found that spore formation by C difficile strains can be increased by exposure to low concentrations of detergents.2 Conversely, chlorine-releasing disinfectants did not have this effect. Chlorine-releasing agents are sporicidal, unlike some other cleaning agents,3 and have been shown to reduce rates of infection by C difficile.4 Thus, chlorine-releasing agents are preferable when cleaning hospital areas where C difficile contamination is likely. The study quoted by Simmons recommended that chlorine-releasing agents rather than neutral detergents are used in such settings. The benefit of deep cleaning in reducing health-care-associated infections remains uncertain, but to suggest that it will be harmful is a leap of faith we do not share. We declare that we have no conflict of interest.
*Chris D Settle, Mark H Wilcox [email protected] Sunderland Royal Hospital, Sunderland SR4 7TP, UK (CDS); and Leeds Teaching Hospitals and University of Leeds, Department of Microbiology, Old Medical School, The General Infirmary, Leeds, UK (MHW) 1 2
Simmons N. War on white coats. Lancet 2007; 370: 2098. Wilcox MH, Fawley WN. Hospital disinfectants and spore formation by Clostridium difficile. Lancet 2000; 356: 1324.
3
4
Fawley WN, Underwood S, Freeman J, et al. Efficacy of hospital cleaning agents and germicides against epidemic Clostridium difficile strains. Infect Control Hosp Epidemiol 2007; 28: 920–25. Wilcox MH, Fawley WN, Wigglesworth N, Parnell P, Verity P, Freeman J. Comparison of the effect of detergent versus hypochlorite cleaning on environmental contamination and incidence of Clostridium difficile infection. J Hosp Infect 2003; 54: 109–14.
Global health research: don’t ignore achievements so far The upcoming November 2008 Global Ministerial Forum on Research for Health (Jan 12, p 91)1 would benefit greatly from an acknowledgment of the progress made since the Mexico City summit on health research in 2004. In August, 2005, the London School of Economics and Political Science released a report on “a dramatic sea change in research into ten neglected diseases [that] could result in at least eight new drugs being developed by 2010 through Public-Private Partnerships (PPPs).”2 In August, 2007, a medical journal published an update on progress made with the world’s most neglected diseases. It stated: “Product development partnerships have been established for at least six neglected diseases in the past seven years without commercial markets or conventional business models, and several new drugs and vaccines are in the pipeline.”3 Over the past few years, the pharmaceutical industry has been constructing research facilities targeted mainly on product development for neglected diseases identified by WHO as essential for the developing world. Pfizer built
DVT (n=25 199)
Control (n=97 773)
Relative risk (95% CI)*
PE (n=16 925)
Control (n=65 793)
Relative risk (95% CI)*
Year 1
Years 2–20
Year 1
Years 2–20
Year 1
Year 1
Years 2–20
Year 1
Years 2–20
Year 1
556
97
1290
3·99 (3·01–5·30) 2·29 (2·07–2·53)
29
178
74
1010
2·72 (1·77–4·17) 1·50 (1·28–1·76)
Number of events 95
Years 2–20
Years 2–20
*Adjusted for sex, age, and year of venous thromboembolism diagnosis.
Table: Relative risk of peripheral atherosclerotic disease during follow-up in patients with venous thrombosis (DVT) or pulmonary embolism (PE), and in population controls
810
www.thelancet.com Vol 371 March 8, 2008
provide direct data on the association between peripheral vascular disease and venous thromboembolism. To address this issue, we extended our analysis of myocardial infarction and stroke to an analysis of a hospital diagnosis of peripheral arterial disease in the study cohorts (25 199 patients with deep venous thrombosis, 16 925 patients with pulmonary embolism, and 163 566 population controls). The risk estimates are provided in the table and were similar to those for myocardial infarction and stroke and are thus consistent with our conclusion that common risk factors or pathways are most likely to be responsible for the association. Meier suggests that patent foramen ovale could be a mediator for the association. The frequency of a recorded diagnosis of patent foramen ovale in our cohorts was 0·02% in patients with venous thrombosis, 0·06% in patients with pulmonary embolism, and 0·02% in population controls. Although patent foramen ovale might be under-reported in the registry, and might even be clinically unrecognised, it is unlikely that a condition with such a low prevalence could be responsible for the associations we saw. We declare that we have no conflict of interest.
*Henrik Toft Sørensen, Erzsebet Horvath-Puho, Lars Pedersen, John A Baron, Paolo Prandoni [email protected] Department of Clinical Epidemiology, Aarhus University Hospital, 8000 Aarhus C, Denmark (HTS, EHP, LP); Department of Epidemiology, Boston University School of Public Health, Boston, MA, USA (HTS); Departments of Medicine and Community and Family Medicine, Dartmouth Medical School, Hanover, NH, USA (JB); and Department of Medical and Surgical Sciences, Thromboembolism Unit, University of Padua, Padua, Italy (PP)
Clostridium difficile and chlorine-releasing disinfectants In a Correspondence letter (Dec 22, p 2098),1 Norman Simmons extrapolates in-vitro research findings in relation to Clostridium difficile spores2 to suggest that “deep cleaning” of hospitals could be harmful. We believe this is misleading. The study quoted found that spore formation by C difficile strains can be increased by exposure to low concentrations of detergents.2 Conversely, chlorine-releasing disinfectants did not have this effect. Chlorine-releasing agents are sporicidal, unlike some other cleaning agents,3 and have been shown to reduce rates of infection by C difficile.4 Thus, chlorine-releasing agents are preferable when cleaning hospital areas where C difficile contamination is likely. The study quoted by Simmons recommended that chlorine-releasing agents rather than neutral detergents are used in such settings. The benefit of deep cleaning in reducing health-care-associated infections remains uncertain, but to suggest that it will be harmful is a leap of faith we do not share. We declare that we have no conflict of interest.
*Chris D Settle, Mark H Wilcox [email protected] Sunderland Royal Hospital, Sunderland SR4 7TP, UK (CDS); and Leeds Teaching Hospitals and University of Leeds, Department of Microbiology, Old Medical School, The General Infirmary, Leeds, UK (MHW) 1 2
Simmons N. War on white coats. Lancet 2007; 370: 2098. Wilcox MH, Fawley WN. Hospital disinfectants and spore formation by Clostridium difficile. Lancet 2000; 356: 1324.
3
4
Fawley WN, Underwood S, Freeman J, et al. Efficacy of hospital cleaning agents and germicides against epidemic Clostridium difficile strains. Infect Control Hosp Epidemiol 2007; 28: 920–25. Wilcox MH, Fawley WN, Wigglesworth N, Parnell P, Verity P, Freeman J. Comparison of the effect of detergent versus hypochlorite cleaning on environmental contamination and incidence of Clostridium difficile infection. J Hosp Infect 2003; 54: 109–14.
Global health research: don’t ignore achievements so far The upcoming November 2008 Global Ministerial Forum on Research for Health (Jan 12, p 91)1 would benefit greatly from an acknowledgment of the progress made since the Mexico City summit on health research in 2004. In August, 2005, the London School of Economics and Political Science released a report on “a dramatic sea change in research into ten neglected diseases [that] could result in at least eight new drugs being developed by 2010 through Public-Private Partnerships (PPPs).”2 In August, 2007, a medical journal published an update on progress made with the world’s most neglected diseases. It stated: “Product development partnerships have been established for at least six neglected diseases in the past seven years without commercial markets or conventional business models, and several new drugs and vaccines are in the pipeline.”3 Over the past few years, the pharmaceutical industry has been constructing research facilities targeted mainly on product development for neglected diseases identified by WHO as essential for the developing world. Pfizer built
DVT (n=25 199)
Control (n=97 773)
Relative risk (95% CI)*
PE (n=16 925)
Control (n=65 793)
Relative risk (95% CI)*
Year 1
Years 2–20
Year 1
Years 2–20
Year 1
Year 1
Years 2–20
Year 1
Years 2–20
Year 1
556
97
1290
3·99 (3·01–5·30) 2·29 (2·07–2·53)
29
178
74
1010
2·72 (1·77–4·17) 1·50 (1·28–1·76)
Number of events 95
Years 2–20
Years 2–20
*Adjusted for sex, age, and year of venous thromboembolism diagnosis.
Table: Relative risk of peripheral atherosclerotic disease during follow-up in patients with venous thrombosis (DVT) or pulmonary embolism (PE), and in population controls
810
www.thelancet.com Vol 371 March 8, 2008