785. Distribution and Associated Mortality in Carbapenem-Resistant Gram-Negative Bacilli in Japan: A Multicenter Study From Multi-Drug Resistant Organisms Clinical Research Network (MDRnet)
Authors: Saito Sho , Sakurai Aki , Uemura Kohei , Matsumara Yasufumi , Hase Ryota , Kato Hideaki , Suzuki Masahiro , Kurokawa Mari , Sakamoto Kota , Shinohara Koh , Sano Kayoko , Suzuki Tetsuya , Hayakawa Kayoko , van Duin David , Ohmagari Norio , Doi Yohei , Doi Yohei 
Published: December 2021

Abstract

Background
Carbapenem-resistant gram-negative bacilli (CRGNB) are increasingly reported around the world as a cause of serious infections. However, the epidemiology and clinical course of patients with CRGNB in Japan is not well understood.

Methods
We prospectively collected CR cases from 4/2019 to 9/2020 in Multi-Drug Resistant organisms clinical research network (MDRnet) consisting of 5 tertiary care facilities in Japan. We looked for all CRGNB, and all unique patients with CR Enterobacterales, CR nonfermenting gram-negative bacilli (NFGNB) and CR Aeromonas sp. isolation were included. Carbapenem resistance was tested by agar dilution method and defined based on the CLSI criteria for each species. Infections were determined by NHSN protocols.

Results
In total, 156 patients (30 Enterobacterales, 119 NFGNB, 7 Aeromonas spp.) were included (11 Enterobacter spp., 11 Klebsiella spp., 86 Pseudomonas aeruginosa, 29 Stenotrophomonas maltophilia, 7 Aeromonas spp.). Acinetobacter sp. was not detected. Isolation sites were sputum (n = 12) and urine (n = 7) in Enterobacterales, sputum (n = 62) and blood (n = 18) in NFGNB, and blood (n = 6) in Aeromonas spp. The median age and male ratio of the patients were 68 years [IQR: 53-74] and 19 (63.3%) in Enterobacterales, 72 years [IQR: 60-79] and 70 (58.8%) in NFGNB and 78 years [IQR: 54-83] and 2 (28.6%) in Aeromonas spp. Ten (33.3%) patients with Enterobacterales, 55 (46.2%) patients with NFGNB, and 6 (85.7%) patients with Aeromonas spp. were infected cases. The others were considered as colonized. There were no patients with ICU stay or intubation in Enterobacterales, while 5 (4.2%) and 4 (3.4%) patients were in ICU and intubated in NFGNB, and 2 patients were in ICU and intubated in Aeromonas spp., respectively. All-cause 30-day mortality rates were 10% in Enterobacterales, 16.8 % in NFGNB and 28.6% in Aeromonas spp. In the infected patients, 3 patients (30%) with Enterobacterales, 12 patients (21.8%) with NFGNB and 1 patient (16.7%) with Aeromonas spp. died within 30 days after isolation.
Flow diagram outlining the characteristics of the patients and species in this study.

Kaplan-Meier survival curves of patients with carbapenem resistant Enterobacterales

Kaplan-Meier survival curves of patients with carbapenem resistant nonfermenting gram-negative bacilli

Conclusion
Mortality rates were high in infected cases of CR Enterobacterales, CR NFGNB and CR Aeromonas spp. Carbapenem-resistant Acinetobacter spp. was not detected, which differed from the CR epidemiology in Europe, the United States, and other Asian countries.

Disclosures
Sho Saito, n/a, Shionogi (Grant/Research Support) David van Duin, MD, PhD, Entasis (Advisor or Review Panel member)genentech (Advisor or Review Panel member)Karius (Advisor or Review Panel member)Merck (Grant/Research Support, Advisor or Review Panel member)Pfizer (Consultant, Advisor or Review Panel member)Qpex (Advisor or Review Panel member)Shionogi (Grant/Research Support, Scientific Research Study Investigator, Advisor or Review Panel member)Utility (Advisor or Review Panel member) Yohei Doi, MD, PhD, AstraZeneca (Speaker's Bureau)bioMerieux (Consultant)FujiFilm (Advisor or Review Panel member, Speaker's Bureau)Gilead (Consultant)GSK (Consultant)Meiji (Consultant)MSD (Consultant)Shionogi (Consultant) Yohei Doi, MD, PhD, Astellas (Individual(s) Involved: Self): Grant/Research Support; AstraZeneca (Individual(s) Involved: Self): Speakers' bureau; bioMerieux (Individual(s) Involved: Self): Consultant, Speakers' bureau; Chugai (Individual(s) Involved: Self): Consultant; Entasis (Individual(s) Involved: Self): Consultant; FujiFilm (Individual(s) Involved: Self): Advisor or Review Panel member; Gilead (Individual(s) Involved: Self): Consultant; GSK (Individual(s) Involved: Self): Consultant; Kanto Chemical (Individual(s) Involved: Self): Grant/Research Support; MSD (Individual(s) Involved: Self): Speaking Fee; Pfizer (Individual(s) Involved: Self): Grant/Research Support; Shionogi (Individual(s) Involved: Self): Grant/Research Support, Speakers' bureau; Teijin Healthcare (Individual(s) Involved: Self): Speakers' bureau; VenatoRx (Individual(s) Involved: Self): Consultant