India superbug resistant to available antibiotics?

  • A woman in the U.S. died after being infected by a superbug during her visit to India, say doctors who found that the “nightmare” bacteria was resistant to all available antibiotics.
  • The infection was caused by carbapenem-resistant Enterobacteriaceae (CRE), a multidrug-resistant organism associated with high mortality.

About Carbapenem-Resistant Enterobacteriaceae:

  • Carbapenem-resistant Enterobacteriaceae (CRE) or carbapenemase-producing Enterobacteriaceae (CPE) are Gram-negative bacteria that are resistant to the carbapenem class of antibiotics, considered the drugs of last resort for such infections.
  • They are resistant because they produce an enzyme called a carbapenemase that disables the drug molecule.
  • The resistance can vary from moderate to severe.
  • Enterobacteriaceae are common commensals and infectious agents.

Risk Factors:

  • Hospitals are primary transmission sites for CRE-based infections. Up to 75% of hospital admissions attributed to CRE were from long-term care facilities or transferred from another hospital.
  • Suboptimal maintenance practices are the largest cause of CRE transmission.
  • This includes the failure to adequately clean and disinfect medication cabinets, other surfaces in patient rooms, and portable medical equipment, such as X-ray and ultrasound machines that are used for both CRE and non-CRE patients.
  • Thus far, CRE have primarily been nosocomial infectious agents.
  • Almost all CRE infections occur in people receiving significant medical care in hospitals, long-term acute care facilities, or nursing homes.
  • Independent risk factors for CRE infection include use of beta-lactam antibiotics and the use of mechanical ventilation. Patients with diabetes have also been shown to be at an elevated risk for acquiring CRE infections

About New Delhi Metallo-beta-lactamase-1 (NDM-1):

  • An enzyme that makes bacteria resistant to a broad range of beta-lactam antibiotics.
  • These include the antibiotics of the carbapenem family, which are a mainstay for the treatment of antibiotic-resistant bacterial infections.
  • 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.
  • NDM-1 was first detected in a Klebsiella pneumoniae isolate from a Swedish patient of Indian origin in 2008.
  • It was later detected in bacteria in India, Pakistan, the United Kingdom, the United States, Canada, and Japan.
  • The most common bacteria that make this enzyme are Gram-negative such as Escherichia coli and Klebsiella pneumoniae, but the gene for NDM-1 can spread from one strain of bacteria to another by horizontal gene transfer.

Antimicrobial resistance (AMR):

  • Antimicrobial resistance (AMR) is the ability of a microbe to resist the effects of medication previously used to treat them.
  • This broader term also covers antibiotic resistance, which applies to bacteria and antibiotics.
  • Resistance arises through one of three ways: natural resistance in certain types of bacteria; genetic mutation; or by one species acquiring resistance from another.
  • Resistance can appear spontaneously because of random mutations; or more commonly following gradual buildup over time, and because of misuse of antibiotics or antimicrobials.
  • Resistant microbes are increasingly difficult to treat, requiring alternative medications or higher doses—which may be more costly or more toxic.
  • Microbes resistant to multiple antimicrobials are called multidrug resistant (MDR); or sometimes superbugs.
  • Antimicrobial resistance is on the rise with millions of deaths every year.
  • A few infections are now completely untreatable because of resistance.
  • All classes of microbes develop resistance (fungi, antifungal resistance; viruses, antiviral resistance; protozoa, antiprotozoal resistance; bacteria, antibiotic resistance).

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