- Email: [email protected]
New Delhi metallo-β-lactamase 1
Correspondence
survived many more hostilities on Earth than human beings did with a far shorter evolutionary experience; the scientific community should therefore rise above social and political controversies to prevent the pathogens from having the last laugh. We have no conflicts of interest.
See Online for webappendix
Indian Network for Surveillance of Antimicrobial Resistance (INSAR) group (webappendix) [email protected] Chacha Nehru Bal Chikitsalaya, Clinical Microbiology and Infectious Diseases, Geeta Colony, Delhi 110031, India 1
2
3
4
5
Kumarasamy KK, Toleman MA, Walsh TR, et al. Emergence of a new antibiotic resistance mechanism in India, Pakistan, and the UK: a molecular, biological, and epidemiological study. Lancet Infect Dis 2010; 10: 597–602. Souli M, Kontopidou FV, Koratzanis E, et al. In vitro activity of tigecycline against multipledrug-resistant, including pan-resistant, Gramnegative and Gram-positive clinical isolates from Greek hospitals. Antimicrob Agents Chemother 2006; 50: 3166–69. Antoniadou A, Kontopidou F, Poulakou G, et al. Colistin-resistant isolates of Klebsiella pneumoniae emerging in intensive care unit patients: first report of a multiclonal cluster. J Antimicrob Chemother 2007; 59: 786–90. Nordmann P, Cuzon G, Naas T. The real threat of Klebsiella pneumoniae carbapenemaseproducing bacteria. Lancet Infect Dis 2009; 9: 228–36. The Times of India. http://timesofindia. indiatimes.com/india/India-trashes-superbugreport-says-its-doctored/articleshow/6301982. cms. Aug 13, 2010. (accessed Aug 15, 2010).
Kumarasamy and colleagues1 have reported strains of Gram-negative bacteria resistant to carbapenems, penicillins, and cephalosporins. I have recently moved to New Delhi after working for more than 11 years within the UK National Health System (NHS) in London. The scientific evidence to support this drug resistance is robust and very relevant to clinical practice today, but to blame New Delhi or India for this problem is unwarranted. I currently work at a tertiary hospital in Haryana, very close to New Delhi, and the antibiotic policies here are as strong and as evidence-based as in the UK. As an oncologist, most of my patients are immunosuppressed. In fact, the incidence of hospital-acquired 750
infections in Haryana is much lower than in the hospitals in London. I have yet to encounter meticillinresistant Staphylococcus aureus, vancomycin-resistant enterococcus, or Clostridium difficile, which was a major issue in all of the foundation NHS trusts I worked at in the UK. The important message is rational use of antibiotics within any clinical setting, and it is absolutely crucial that we do not digress from this. I would urge the medical community to consider changing the name of the resistance mechanism to carbapenem-resistant metallo-β-lactamase. I have no conflicts of interest.
Bhawna Sirohi [email protected] Artemis Cancer Centre, Medical Oncology, Artemis Health Sciences, Gurgaon, Haraya 122001, India 1
Kumarasamy KK, Toleman MA, Walsh TR, et al. Emergence of a new antibiotic resistance mechanism in India, Pakistan, and the UK: a molecular, biological, and epidemiological study. Lancet Infect Dis. 2010; 10: 597–602.
Kumarasamy and colleagues1 should be complimented for providing invaluable data on antibiotic resistance; however, I wish to raise a few concerns regarding the Article. The investigators studied the prevalence of isolates with NDM-1. How the investigators ensured that bias was eliminated is important. To recognise the accurate prevalence rate, it is crucial to know details of how the isolates were obtained. For instance, many isolates obtained from the same patient at different times will overestimate the prevalence. Consider an extreme example: samples obtained from ten patients (with NDM-1 positive organisms) on ten consecutive days could lead to 100 positive isolates and therefore an extraordinary overestimation of the prevalence. The investigators mention that from Chennai, 141 isolates of 3521 Enterobacteriaceae were resistant to carbapenem, and of these 141,
44 were NDM-1 positive. How many and what type of patients these 3521 isolates were obtained from is unclear. For the UK data, the investigators clearly mention that 37 isolates from 29 patients were obtained. Thus, it seems that more than one sample was collected from each patient; whether these were two different samples (eg, blood and urine) or the same sample on two different occasions should be clarified. If the samples were the same but on two different occasions, then what was the time between the two samples being collected? It is also unclear which type of hospital or patients these isolates were obtained from. One would expect that patients were admitted to hospitals; however, it is stated that isolates from Chennai and Haryana were primarily from community-acquired infections. This information is very confusing and further emphasises the need to provide data on patients and sample collection. The UK isolates were identified from referrals to the Antibiotic Resistance Monitoring and Reference Laboratory by UK microbiology laboratories. Whether such referral is common practice for all isolates showing antibiotic resistance or for a select few should be clarified to assure readers about the accuracy of the reported prevalence rates. Resistance to antibiotics is a worldwide occurrence,2,3 and indiscriminate antibiotic use is a major factor for emergence of resistant bacterial strains.4 From Kumarasamy and colleagues’ Article, it seems that NDM-1 is perhaps localised to the regions in the study, however, it could be present in other parts of the world. Non-reporting does not mean non-existence. Finally, patients opt for corrective surgery in India not only because it saves money, but also because care is equivalent or better care than in their home countries. The investigators’ suggestion that the UK NHS might eventually spend substantially more by promoting medical tourism to India is purely
www.thelancet.com/infection Vol 10 November 2010
survived many more hostilities on Earth than human beings did with a far shorter evolutionary experience; the scientific community should therefore rise above social and political controversies to prevent the pathogens from having the last laugh. We have no conflicts of interest.
See Online for webappendix
Indian Network for Surveillance of Antimicrobial Resistance (INSAR) group (webappendix) [email protected] Chacha Nehru Bal Chikitsalaya, Clinical Microbiology and Infectious Diseases, Geeta Colony, Delhi 110031, India 1
2
3
4
5
Kumarasamy KK, Toleman MA, Walsh TR, et al. Emergence of a new antibiotic resistance mechanism in India, Pakistan, and the UK: a molecular, biological, and epidemiological study. Lancet Infect Dis 2010; 10: 597–602. Souli M, Kontopidou FV, Koratzanis E, et al. In vitro activity of tigecycline against multipledrug-resistant, including pan-resistant, Gramnegative and Gram-positive clinical isolates from Greek hospitals. Antimicrob Agents Chemother 2006; 50: 3166–69. Antoniadou A, Kontopidou F, Poulakou G, et al. Colistin-resistant isolates of Klebsiella pneumoniae emerging in intensive care unit patients: first report of a multiclonal cluster. J Antimicrob Chemother 2007; 59: 786–90. Nordmann P, Cuzon G, Naas T. The real threat of Klebsiella pneumoniae carbapenemaseproducing bacteria. Lancet Infect Dis 2009; 9: 228–36. The Times of India. http://timesofindia. indiatimes.com/india/India-trashes-superbugreport-says-its-doctored/articleshow/6301982. cms. Aug 13, 2010. (accessed Aug 15, 2010).
Kumarasamy and colleagues1 have reported strains of Gram-negative bacteria resistant to carbapenems, penicillins, and cephalosporins. I have recently moved to New Delhi after working for more than 11 years within the UK National Health System (NHS) in London. The scientific evidence to support this drug resistance is robust and very relevant to clinical practice today, but to blame New Delhi or India for this problem is unwarranted. I currently work at a tertiary hospital in Haryana, very close to New Delhi, and the antibiotic policies here are as strong and as evidence-based as in the UK. As an oncologist, most of my patients are immunosuppressed. In fact, the incidence of hospital-acquired 750
infections in Haryana is much lower than in the hospitals in London. I have yet to encounter meticillinresistant Staphylococcus aureus, vancomycin-resistant enterococcus, or Clostridium difficile, which was a major issue in all of the foundation NHS trusts I worked at in the UK. The important message is rational use of antibiotics within any clinical setting, and it is absolutely crucial that we do not digress from this. I would urge the medical community to consider changing the name of the resistance mechanism to carbapenem-resistant metallo-β-lactamase. I have no conflicts of interest.
Bhawna Sirohi [email protected] Artemis Cancer Centre, Medical Oncology, Artemis Health Sciences, Gurgaon, Haraya 122001, India 1
Kumarasamy KK, Toleman MA, Walsh TR, et al. Emergence of a new antibiotic resistance mechanism in India, Pakistan, and the UK: a molecular, biological, and epidemiological study. Lancet Infect Dis. 2010; 10: 597–602.
Kumarasamy and colleagues1 should be complimented for providing invaluable data on antibiotic resistance; however, I wish to raise a few concerns regarding the Article. The investigators studied the prevalence of isolates with NDM-1. How the investigators ensured that bias was eliminated is important. To recognise the accurate prevalence rate, it is crucial to know details of how the isolates were obtained. For instance, many isolates obtained from the same patient at different times will overestimate the prevalence. Consider an extreme example: samples obtained from ten patients (with NDM-1 positive organisms) on ten consecutive days could lead to 100 positive isolates and therefore an extraordinary overestimation of the prevalence. The investigators mention that from Chennai, 141 isolates of 3521 Enterobacteriaceae were resistant to carbapenem, and of these 141,
44 were NDM-1 positive. How many and what type of patients these 3521 isolates were obtained from is unclear. For the UK data, the investigators clearly mention that 37 isolates from 29 patients were obtained. Thus, it seems that more than one sample was collected from each patient; whether these were two different samples (eg, blood and urine) or the same sample on two different occasions should be clarified. If the samples were the same but on two different occasions, then what was the time between the two samples being collected? It is also unclear which type of hospital or patients these isolates were obtained from. One would expect that patients were admitted to hospitals; however, it is stated that isolates from Chennai and Haryana were primarily from community-acquired infections. This information is very confusing and further emphasises the need to provide data on patients and sample collection. The UK isolates were identified from referrals to the Antibiotic Resistance Monitoring and Reference Laboratory by UK microbiology laboratories. Whether such referral is common practice for all isolates showing antibiotic resistance or for a select few should be clarified to assure readers about the accuracy of the reported prevalence rates. Resistance to antibiotics is a worldwide occurrence,2,3 and indiscriminate antibiotic use is a major factor for emergence of resistant bacterial strains.4 From Kumarasamy and colleagues’ Article, it seems that NDM-1 is perhaps localised to the regions in the study, however, it could be present in other parts of the world. Non-reporting does not mean non-existence. Finally, patients opt for corrective surgery in India not only because it saves money, but also because care is equivalent or better care than in their home countries. The investigators’ suggestion that the UK NHS might eventually spend substantially more by promoting medical tourism to India is purely
www.thelancet.com/infection Vol 10 November 2010