New strains of ‘Gram-negative’ bacteria have become resistant to all safe antibiotics. The bacteria, classified as Gram-negative because of their reaction to the so-called Gram stain test, can cause severe pneumonia and infections of the urinary tract, bloodstream, and other parts of the body. Their cell structure makes them more difficult to attack with antibiotics than Gram-positive organisms such as MRSA. The only antibiotics — colistin and polymyxin B — that still have efficacy against Gram-negative bacteria produce dangerous side effects: kidney damage and nerve damage. Patients who are infected with Gram-negative bacteria must make the unsavoury choice between life with kidney damage or death with intact kidneys. Recently, some new strains of Gram-negative bacteria have shown resistance against even colistin and polymyxin B. Infection with these new strains typically means death for the patient. - The New York Times