Clinical Features, Genome Epidemiology, and Antimicrobial Resistance Profiles of Aeromonas spp. Causing Human Infections: A Multicenter Prospective Cohort Study

Background

The genus Aeromonas is increasingly implicated in human infections, but knowledge of its clinical characteristics and antimicrobial resistance profiles has been limited owing to its complex taxonomy.

Methods

We conducted a multicenter prospective cohort study of patients with Aeromonas infections at hospitals across Japan. Patients were eligible for inclusion if they had an Aeromonas spp. strain in a clinical culture and were considered infected at the culture site. Clinical data were collected, and isolates underwent susceptibility testing and whole-genome sequencing.

Results

A total of 144 patients were included. Hepatobiliary infection accounted for a majority of infections (73% [105 of 144]), which mostly occurred in elderly patients with comorbid conditions, including hepatobiliary complications. The all-cause 30-day mortality rate was 10.0% (95% confidence interval, 4.9%-14.8%). By whole-genome sequencing, 141 strains (98%) belonged to 4 Aeromonas species-A caviae, A hydrophila, A veronii, and A dhakensis-with significant intraspecies diversity. A caviae was predominant in all infection sites except skin and soft tissue, for which A hydrophila was the prevailing species. The genes encoding chromosomally mediated class B, C, and D β-lactamases were harbored by 92%-100% of the isolates in a species-specific manner, but they often lacked association with resistance phenotypes. The activity of cefepime was reliable. All isolates of A hydrophila and A dhakensis carried an mcr-3-like colistin resistance gene and showed reduced susceptibility to colistin.

Conclusions

Hepatobiliary tract was the most common infection site of Aeromonas spp., with A caviae being the dominant causative species. The resistance genotype and phenotype were often incongruent for β-lactam agents.

The profile of patients hospitalized with COVID-19 under the Quarantine Act in a designated hospital near an international airport in Japan

The Japanese Government has implemented quarantine measures in response to the COVID-19 pandemic. Individuals testing positive at the airport's quarantine office were lodged either in a designated hotel or hospital under the Quarantine Act. The aim of this study is to describe the management of patients with COVID-19 admitted under the Quarantine Act and to evaluate its impact on medical resources. Data were retrospectively collected, including demographics, comorbidities, status at admission, clinical condition, treatment, outcomes, status at discharge, duration of hospitalization, and the cost of hospitalization for all patients hospitalized with COVID-19 at this facility under the Quarantine Act between January 2020 and April 2021. A total of 48 patients (39 males, 9 females; median age: 38.5 years) with COVID-19, half (52.1%) of which were Japanese, were hospitalized under the Quarantine Act. The majority (87.5%) of the patients lived or planned to stay outside of Chiba Prefecture. The most frequent time of admission was 9 PM-1 AM. Hypoxia on admission was observed in 10 (20.8%) patients and oxygen therapy was provided to 8 (16.7%). One patient died due to respiratory failure. The median duration of hospitalization was 11 days. The total cost of hospitalization was 82,705,289 yen (approximately $760,000), which was covered by public funds. Patients hospitalized with COVID-19 under the Quarantine Act were younger and less severely ill than inpatients with COVID-19 from among the general population in Japan (according to a COVID-19 registry), but consumed a significant amount of medical resources at this hospital. An efficient system to manage patients with COVID-19 in designated hotels should be created and indications for hospitalization should be determined.

A Favipiravir-induced Fever in a Patient with COVID-19

We herein report the first case of a fever induced by favipiravir, a potential coronavirus disease 2019 therapeutic drug. An 82-year-old man diagnosed with bilateral pneumonia was transferred to our hospital following a positive severe acute respiratory syndrome coronavirus 2 polymerase chain reaction test. He was treated with compassionate use of favipiravir. Both his oxygen demand and fever gradually improved after admission; however, his fever relapsed, and the C-reactive protein (CRP) levels increased on day 7. We diagnosed his fever as being favipiravir-induced. The fever resolved a few days after favipiravir discontinuation, demonstrating the accuracy of the diagnosis. This case revealed that favipiravir can induce a fever.

A case of imported COVID-19 diagnosed by PCR-positive lower respiratory specimen but with PCR-negative throat swabs

A 35-year-old woman presented with fever and mild diarrhoea without any respiratory symptoms 9 days after travelling to Japan from Wuhan, China. Her computed tomography scan revealed pneumonia. The first polymerase chain reaction (PCR) test on throat swab for the novel corona virus upon admission was negative. Therefore, she was treated for community-acquired pneumonia, but fever persisted. On hospital day 5, PCR test on induced sputum was positive, but a second polymerase chain reaction test on throat swab remained negative. She was discharged, fully recovered, on hospital day 12. A lower respiratory tract specimen should be obtained for better diagnosis of corona virus disease 2019, even in the absence of respiratory symptoms for patients with significant travel or exposure history.