Treatment of a challenging NDM and OXA-48-producing Klebsiella pneumoniae causing skin and soft tissue infection and exhibiting resistance to the combination of Ceftazidime-Avibactam and Aztreonam: A case report

Carbapenem-resistant Enterobacterales (CRE) pose a significant public health concern. CRE could be carbapenamse producers or non-producers. In the Kingdom of Saudi Arabia, blaOXA-48 and blaNDM represent the majority of carbapenemase isolates. There are very limited treatment options for carbapenemase-producing CRE caused by blaNDM. Ceftazidime-avibactam plus aztreonam (CZA-ATM) or cefiderocol as monotherapy are considered the treatment of choice for these infections. Here, we report a case of a 70-year-old man presented with surgical site infection of above knee amputation stump. The cultures revealed carbapenem-resistant Klebsiella pneumoniae positive for blaNDM and blaOXA-48 resistant to CZA-ATM therapy and intermediate susceptibility to tigecycline. He was started on CZA-ATM both adjusted for renal function, and high dose tigecycline with daily wound dressing and irrigation. By day 20 of the antibiotic regimens, he had clinical and microbiological cure based on repeated wound cultures. This case identifies a rare incidence of CRE skin and soft tissue infection positive for blaNDM and blaOXA-48 resistant to CZA-ATM in a background of limited targeted options, but successfully treated with CZAATM and high-dose tigecycline. Such therapeutic approach might be useful in few circumstances when no other antibiotic options are available to treat extensively drug-resistant Klebsiella pneumoniae.