NPPA and infection: However, effective infection control has been achieved using antibiotic combinations that leverage heteroresistance to multiple drugs.3,8 We identified a clinical isolate CR-Kp Kp486 as resistant to multiple antibiotics and exhibiting heteroresistance to four antibiotics involved the last-line antibiotics (amikacin, ceftazidime/avibactam, tigecycline and polymyxin B) (Figure 5 and Table S4).