NEW DELHI METALLOBETALACTAMASE

1. New Delhi metallo-beta-lactamase (NDM-1)Facts, Controversies, Solutionsan update Dr.T.V.Rao MD Dr.T.V.Rao MD.

2. Bugs becomes Superbugs • Antibiotic resistance develops through gene action or plasmid exchange between bacteria of the same species. If a bacterium carries several resistance genes, it is called multiresistant or, informally, a superbug. Dr.T.V.Rao MD.

3. CDCreports • CDC reports that nearly 2 million health care-associated infections (HAIs) and 90,000 HAI-related deaths occur annually in the U.S. Many of these infections and deaths are caused by antibiotic-resistant infections. Dr.T.V.Rao MD.

4. CDC Reports Three Enterobacteriaceae isolates carrying a newly described resistance mechanism, the New Delhi metallo-beta-lactamase (NDM-1) , were identified from three U.S. states at the CDC antimicrobial susceptibility laboratory. This is the first report of NDM-1 in the United States, and the first report of metallo-beta-lactamase carriage among Enterobacteriaceae in the United States Dr.T.V.Rao MD.

5. CDC reports the new genetic mechanisms • The isolate, Klebseilla pneumoniae 05-506, was shown to possess a metallo-beta-lactamase (MBL) but was negative for previously known MBL genes. Gene libraries and amplification of class 1 integrons revealed three resistance-conferring regions; the first contained bla(CMY-4) flanked by ISEcP1 and blc. The second region of 4.8 kb contained a complex class 1 integron with the gene cassettes arr-2, a new erythromycin esterase gene; ereC; aadA1; and cmlA7 Dr.T.V.Rao MD.

6. Molecular configuration of NDM-1 • NDM-1 also has an additional insert between positions 162 and 166 not present in other MBLs. NDM-1 has a molecular mass of 28 kDa, is monomeric, and can hydrolyze all beta-lactams except aztreonam. Compared to VIM-2, NDM-1 displays tighter binding to most Cephalosporins. Dr.T.V.Rao MD.

7. Antibiotic Misuse certain to Create Superbugs • Antibiotic misuse, (sometimes called antibiotic abuse or antibiotic overuse) refers to the misuse and overuse of Antibioticswhich has serious effects on public health. Antibiotic resistant bacteria is a growing threat and becoming increasingly common. This overuse creates multi-antibiotic resistant life threatening infections by "super bugs", sometimes out of relatively harmless bacteria. Antibiotic abuse also places the patient at unnecessary risk of adverse effects of antibiotics. Dr.T.V.Rao MD.

8. Extended-Spectrum ß-lactamaseEarly Beginning • Microbial resistance through Extended-Spectrum ß-lactamase was first reported in the early 1980s in Europe and subsequently in the US soon after the introduction of 3rd generation cephalosporins in clinical practice. Today, this resistance mechanism has emerged globally, and ESBL-producing Enterobacteriaceae are recognized worldwide as nosocomial pathogens of major importance. Dr.T.V.Rao MD.

9. New Delhi metallo-beta-lactamase 1 a Super bug • New Delhi Metallo-beta-lactamase (NDM-1) is a gene that makes bacteria resistant to antibiotics of the carbapenems family. It encodes a type of beta-lactamase enzyme called a carbapenemase. Bacteria that carry this gene are often referred as "superbugs gene transfer.’ Dr.T.V.Rao MD.

10. What is New Delhi metallo-beta-lactamase 1 • New Delhi metallo-beta-lactamase 1 (NDM-1) is a newly-described metallo-beta-lactamase (MBL), first identified in 2008 in single isolates of Klebsiella pneumoniae and Escherichia coli, both recovered from a patient repatriated to Sweden after treatment in a hospital in New Delhi, India . Like other acquired MBLs, NDM-1 hydrolyses all beta-lactam antibiotics except for aztreonam, which is usually inactivated by co-produced extended-spectrum or AmpC beta-lactamases. Dr.T.V.Rao MD.

11. NDM-1 • K. pneumoniae containing NDM-1 was first discovered in 2008. By 2009, a study in Mumbai revealed 24 carbapenem-resistant Enterobacteriaceae, 22 of which were NDM-1 producers. Of these 22 organisms, 10 were klebsiella species, 9 were Escherichia coli, 2 were enterobacter species, and 1 was Morganella morganii— illustrating the ability of the plasmid to spread rapidly among strains of Enterobacteriaceae Dr.T.V.Rao MD.

12. Origin and spread of NDM-1 • The NDM-1 enzyme was named after New Delhi, the capital city of India, as it was first described by Yong et al. in December 2009 in a Swedish national who fell ill with an antibiotic-resistant bacterial infection that he acquired in India.[12] The infection was unsuccessfully treated in a New Delhi hospital, and, after the patient's repatriation to Sweden, a carbapenem-resistant Klebsiella pneumoniae strain bearing the novel gene was identified Dr.T.V.Rao MD.

13. The NDM-1 spreads through Plasmids • Resistance that is spread via plasmid can move with incredible speed; its emergence is not dependent on a bacterium's exposure to a drug, or on a mother bacterium passing the resistance pattern down to daughter cells. The researchers' results prove that NDM-1 has spread widely, because they found it not only in hospital patients, but also outside in the community, causing common illnesses such as urinary tract infections. Dr.T.V.Rao MD.

14. NDM – 1 a Public Health Concern • Acquired carbapenemases confer extensive antibiotic resistance to Enterobacteriaceae and represent a public health threat. A novel acquired carbapenemase, New Delhi metallo-beta-lactamase 1 (NDM-1), has recently been described in the United Kingdom and Sweden, mostly in patients who had received care on the Indian subcontinent. Dr.T.V.Rao MD.

15. The Lancet Opens the Pandora box • Gram-negative Enterobacteriaceae with resistance to carbapenems conferred by New Delhi metallo-β-lactamase 1 (NDM-1) are potentially a major global health problem. We investigated the prevalence of NDM-1, in multidrug-resistant Enterobacteriaceae in India, Pakistan, and the UK. Dr.T.V.Rao MD.

16. Travel makes patients venerable • The superbug called New Delhi metallo-beta-lactamase, or NDM-1, was identified in 50 people who traveled to India or Pakistan for surgery and then returned to the United Kingdom, British scientists reported in the journal Lancet Infectious Diseases Dr.T.V.Rao MD.

17. Naming the strain as New Delhi creates controversy • The gene was named after New Delhi, the capital city of India, as it was first described by Yong et al. in 2009 in a Swedish national who fell ill with an antibiotic-resistant bacterial infection that he acquired in India . The infection was unsuccessfully treated in a New Delhi hospital and after the patient's repatriation to Sweden, a carbapenem-resistant Klebsiella pneumoniaestrain bearing the novel gene was identified. The presenting authors concluded that the new resistance mechanism "clearly arose in India, but there are few data arising from India to suggest how widespread it is." Dr.T.V.Rao MD.

18. NDM 1– A beta lactamase enzyme • The gene for NDM-1 is one member of a large gene family that encodes beta-lactamase enzymes called carbapenemases. Bacteria that produce carbapenemases are often referred to in the news media as "superbugs" because infections caused by them are difficult to treat. Such bacteria are usually susceptible only to polymyxins and tigecycline Dr.T.V.Rao MD.

19. Molecular Basis of NDM 1 • NDM-1 was first detected in a Klebsiella pneumoniae isolate from a Swedish patient of Indian origin in 2008. The gene coding for this unique enzyme blaNDM-1 was found in one of the three resistance-carrying regions of an integron. NDM-1 shares very little identity with other MBLs. As well as possessing unique residues near the active site, NDM-1 also has an additional insert between positions 162 and 166, which is not present in other MBLs. NDM-1 has a molecular mass of 28 kD and is monomeric Dr.T.V.Rao MD.

20. CDC the clarifies new genetic mechanisms in NDM -1 • The isolate, Klebseilla pneumoniae 05-506, was shown to possess a metallo-beta-lactamase (MBL) but was negative for previously known MBL genes. Gene libraries and amplification of class 1 integrons revealed three resistance-conferring regions; the first contained bla(CMY-4) flanked by ISEcP1 and blc. The second region of 4.8 kb contained a complex class 1 integron with the gene cassettes arr-2, a new erythromycin esterase gene; ereC; aadA1; and cmlA7 Dr.T.V.Rao MD.

21. Genetic origin of the NDM-1 is Complex • An intact ISCR1 element was shown to be downstream from the qac/sul genes. The third region consisted of a new MBL gene, designated bla(NDM-1), flanked on one side by K. pneumoniae DNA and a truncated IS26 element on its other side. The last two regions lie adjacent to one another, and all three regions are found on a 180-kb region that is easily transferable to recipient strains and that confers resistance to all antibiotics except fluoroquinolones and colistin. NDM-1 shares very little identity with other MBLs, with the most similar MBLs being VIM-1/VIM-2, with which it has only 32.4% identity. Dr.T.V.Rao MD.

22. Molecular Configuration of NDM-1 • NDM-1 also has an additional insert between positions 162 and 166 not present in other MBLs. NDM-1 has a molecular mass of 28 kDa, is monomeric, and can hydrolyze all beta-lactams except aztreonam. Compared to VIM-2, NDM-1 displays tighter binding to most Cephalosporins. Dr.T.V.Rao MD.

23. NDM genetic coding differs from other recent isolates • Compared to VIM-2, NDM-1 displays tighter binding to most cephalosporins, in particular, cefuroxime, cefotaxime, and cephalothin (cefalotin), and also to the penicillins. NDM-1 does not bind to the carbapenems as tightly as IMP-1 or VIM-2 and turns over the carbapenems at a rate similar to that of VIM-2. In addition to K. pneumoniae 05-506, bla(NDM-1) was found on a 140-kb plasmid in an Escherichia coli strain isolated from the patient's feces, inferring the possibility of in vivo conjugation Dr.T.V.Rao MD.

24. CLSI guidelines for assessing the antibiograms pattern • All patients colonized or infected with CRE or carbapenemase-producing Enterobacteriaceae should be placed on contact precautions. Acute care facilities should establish a protocol, in conjunction with CLSI guidelines, to detect nonsusceptibility and carbapenemase production in Enterobacteriaceae,particularly Klebseilla spp. and Escherichia coli, and immediately alert epidemiology and infection control staff members if identified Dr.T.V.Rao MD.

25. Laboratory Detection and Identification NDM – 1 detection Methods Dr.T.V.Rao MD.

26. Phenotypic Methods helps in Basic Identification of Resistance • Carbapenems resistance mediated by NDM-1 enzyme has been detected by clinical laboratories with routine phenotypic testing methods, including disc diffusion testing Dr.T.V.Rao MD.

27. When to suspect Resistant Bacterial Isolate as Carbapenemase Producer • Any Enterobacteriaceae isolate that exhibits a minimum inhibitory concentration (MIC) above the epidemiological cut-off or with clinical resistance to ertapenem, imipenem or meropenem should trigger further testing Carbapenemase activity can be screened by using the modified Hodge test and, as with other metallo-beta-lactamases, synergy can be detected by EDTA-imipenem disc or Etest. Dr.T.V.Rao MD.

28. The Modified Hodge Test The Modified Hodge Test is a phenotypic confirmatory test for “Carapnemase” activity and is indicated when there is a positive screening test and resistance to one or more agents in cephalosporin subclass III (i.e., cefoperazone, cefotaxime, ceftazidime, ceftizoxime, and ceftriaxone) Be aware that imipenem disk tests perform poorly as a screen for carbapenemases. Dr.T.V.Rao MD.

29. Phenotypic detection with Hodge test a Minimal Requirement Carbapenem resistance and carbapenemase production conferred by blaNDM-1 is detected reliably with phenotypic testing methods currently recommended by the Clinical and Laboratory Standards Institute , including disk diffusion testing and the modified Hodge test Dr.T.V.Rao MD.

30. The Modified Hodge Test (MHT) • The Modified Hodge Test (MHT) detects carbapenemase production in isolates of Enterobacteriaceae • Carbapenemase production is detected by the MHT when the test isolate produces the enzyme and allows growth of a carbapenem susceptible strain (E.coli ATCC 25922) towards a carbapenem disk Dr.T.V.Rao MD.

31. NDM 1 can be detected by VITEK system and E-test • Carbapenems resistance and carbapenemase production conferred by blaNDM-1 is detected reliably with phenotypic testing methods currently in use in routine laboratories including VITEK 2 and Etest Dr.T.V.Rao MD.

32. Advanced Expert System indicates Resistance patterns • Advanced Expert System™ (AES) can reliably detect thecarbapenemase resistant phenotype. bioART offers an additional tool that can be customized to alert users to carbapenems resistance patterns Dr.T.V.Rao MD.

33. Limitation of Automated systems in Detection • Widely used automated susceptibility systems show good sensitivity but poor specificity for detection of carbapenems resistance mediated by NDM-1 and other carbapenemases Dr.T.V.Rao MD.

34. NDM-1 needs confirmation by Molecular Methods • Confirmation of the NDM-1 enzyme requires molecular analysis, typically PCR or DNA sequencing, by a reference laboratory Dr.T.V.Rao MD.

35. Mark Toleman of Britain's Cardiff University School of Medicine, creates concerns ? • The inhabitants of New Delhi are continually being exposed to multidrug-resistant and NDM 1-positive bacteria," said Mark Toleman of Britain's Cardiff University School of Medicine, who published the findings in a study on Thursday. Dr.T.V.Rao MD.

36. Toleman’s Study a Concern to India • Toleman’s study, carried out with Cardiff University’s Timothy Walsh and published in The Lancet Infectious Diseases journal, investigated how common NDM 1-producing bacteria are in community waste seepage — such as water pools or rivulets in streets — and tap water in urban New Delhi. Dr.T.V.Rao MD.

37. Controversies will Continue How we can set right our house in order Dr.T.V.Rao MD.

38. What is the Professional Thinking • The suspicion is indiscriminate usage of antibiotics for immediate gain might have contributed to development of such a ‘super superbug’ along with poor sanitation which would not be cleansing drug saturated human waste in appropriate manner. India does not have any systematic ways of managing and controlling drugs dispensed by private doctors nor there are financial incentives both for doctors and patients to be ‘guarded’ in usage of antibiotics. Dr.T.V.Rao MD.

39. NDM -1- A Universal Concern • Recent experiences with large epidemics of KPC and VIM carbapenemase-producing Enterobacteriaceae associated with significant mortality in the US, Greece and Israel, have highlighted the need for strengthening public health and the response capacity of healthcare systems, notably by dedicated national task forces and public health laboratory networks. Dr.T.V.Rao MD.

40. Role of Microbiologists • Microbiologists in India have a very important role in the prevention of spread of these dreaded multiresistant pathogens across the world. They should actively participate in the clinical decision making with regard to the treatment of infections, influence the policies and approach to infections and antimicrobials by the government, develop guidelines for antibiotic therapy in their local hospitals, become infection-control doctors, set up surveillance systems for drug-resistant organisms, and educate healthcare workers and the general public about the dangers of multidrug resistant organisms, including hospital-acquired infections. Dr.T.V.Rao MD.

41. Measures that can decrease antibiotic resistance • Measures that guide antibiotic prescribing are likely to decrease antibiotic resistance in hospitals.32-34 Such measures include: • Obtaining cultures • Take appropriate and early cultures before initiating empiric antibiotic therapy, • and streamline antibiotic treatment based on the culture results35 • Monitoring local antibiotic resistance patterns • Being aware of local antibiotic resistance patterns (Antibiograms) enables • appropriate selection of initial empiric antibiotic therapy Dr.T.V.Rao MD.

42. Role of Microbiology Department • Microbiology departments asses trends in development of antimicrobial resistance. • The results of sensitivity/resistance patterns should be correlated with Antimicrobial agents currently used in the Hospital. • Identify and forecast that nature of relation between antibiotic use and resistance. Dr.T.V.Rao MD.

43. Microbiology Services • Constant up graduation of Microbiology departments is good investment. • Quality control methods in testing of antibiotic resistance pattern is a top priority. Dr.T.V.Rao MD.

44. Better services from Microbiology Departments. • Basic infrastructure should be updated for detection of MRSA and ESBL producers, And Carbapenemase producers • Documentation of all Opportunistic infections. and Hospital infection outbreaks Dr.T.V.Rao MD.

45. New Innovations in Diagnostic Microbiology • New rapid diagnostic tests would greatly facilitate clinical trials of critically needed new antibiotics. The tests would enable investigators to identify potential study subjects more easily, which would permit smaller and less expensive studies of antibiotics as they move through development Dr.T.V.Rao MD.

46. Up gradation of Diagnostic Microbiology Laboratories a Must • The modern generation of Microbiologists should be familiar with Identification of the Microbes with newer generation of Technological advances. Dr.T.V.Rao MD.

47. Share your Observations on www • Today sharing the knowledge on Microbes through World Wide Web (WWW) helps for faster dissemination of Knowledge and many lives in the Developing world can be saved Dr.T.V.Rao MD.

48. Research on Emerging Infectious Disease Agents • The development of vaccines and antimicrobial drugs and the remarkable eradication of smallpox had created hope that infectious diseases could be controlled or even eliminated. However, the current realization that infectious diseases continue to emerge and re-emerge (including the possibility of bioterrorism), underscores the challenges ahead in infectious disease research. Dr.T.V.Rao MD.

49. Caution ….Donot discard Unfamiliar bacteria in the routine Diagnostic work • Many important pathogens both unfamiliar, emerging and reemerging are discarded without much consideration and review. • Be wise to consult a colleague and some one who is more familiar Dr.T.V.Rao MD.

50. Best way to keep the matters in Order Every Hospital should have a policy which is practicable to their circumstances. Rigid guidelines without coordination will lead to greater failures The only way to keep Antimicrobial agents useful is to use them appropriately and Judiciously (Burke A.Cunha, MD,MACP Antimicrobial Therapy. Medical Clinics of North America NOV 2006) Dr.T.V.Rao MD.