Safely Prescribing Nirmatrelvir and Ritonavir-Avoiding Drug-Drug Interactions.

This Teachable Moment discusses drug-drug interactions with nirmatrelvir and ritonavir (Paxlovid) treatment for COVID-19 and considerations when prescribing.

Mycobacterium goodii central venous catheter-related bloodstream infection.

Mycobacterium goodii is a rapidly growing nontuberculous mycobacterium that was first described in 1999. Previous case reports of M. goodii have been associated with prosthetic tissue infection or soft tissue infection. To our knowledge, there is only one previous case report on M. goodii catheter-related infection. Here we report a case of central venous catheter infection with M. goodii complicated by bacteremia.

Delayed diagnosis of severe falciparum malaria in a patient presenting with acute gastroenteritis in West Texas.

Falciparum malaria is a life-threatening infection that affects both people in endemic areas and people who travel to endemic areas. Malaria in exceedingly rare in West Texas, but the initial recognition and prompt initiation of antimalarial treatment are crucial in managing malaria. Here we present a case of a 31-year-old woman who was initially diagnosed with acute gastroenteritis and was later found to have cerebral malaria.

In vitro and in vivo activity of single and dual antimicrobial agents against KPC-producing Klebsiella pneumoniae.

Objectives: Options for treatment of infections due to KPC-producing Klebsiella pneumoniae are limited and combination therapy is often recommended. In this report, the in vitro and in vivo activity of potential therapeutic agents and combinations was assessed against four KPC-producing K. pneumoniae isolates. Methods: Using clinically relevant concentrations, time-kill experiments and the Galleria mellonella model of infection were used to examine the activity of polymyxin B, ceftazidime/avibactam, meropenem, rifampicin and amikacin alone and in combination. Results: Two K. pneumoniae isolates were resistant to polymyxin B and had ceftazidime/avibactam MICs of 8/4 mg/L. When ceftazidime/avibactam was combined with either amikacin or meropenem, synergy was observed in vitro, and these combinations were associated with improved survival in the in vivo model. Improved survival was also observed using higher doses of ceftazidime/avibactam. The other two K. pneumoniae isolates were susceptible to polymyxin B and had lower (1/4 mg/L) MICs of ceftazidime/avibactam. For these two isolates, bactericidal activity was observed in vitro at ceftazidime/avibactam concentrations four times the MIC. At one-quarter of the MIC, synergy was observed when ceftazidime/avibactam was combined with meropenem. In the in vivo model with the two susceptible isolates, improved survival rates were observed following therapy with ceftazidime/avibactam monotherapy. For all four isolates, polymyxin B with or without rifampicin or meropenem performed poorly in the in vivo model. Conclusions: Pending clinical studies, combining ceftazidime/avibactam with another agent (e.g. a carbapenem) should be considered when treating serious infections due to these pathogens, particularly for isolates with ceftazidime/avibactam MICs near the susceptibility breakpoint.