Difference in the impact of coinfections and secondary infections on antibiotic use in patients hospitalized with COVID-19 between the Omicron-dominant period and the pre-Omicron period.

INTRODUCTION: This study evaluated the effect of coinfections and/or secondary infections on antibiotic use in patients hospitalized with coronavirus disease 2019 (COVID-19). METHOD: Days of therapy per 100 bed days (DOT) in a COVID-19 ward were compared between 2022 (Omicron period) and 2021 (pre-Omicron period). Antibiotics were categorized as antibiotics predominantly used for community-acquired infections (CAIs) and antibiotics predominantly used for health care-associated infections (HAIs). Bacterial and/or fungal infections which were proved or assumed on admission were defined as coinfections. Secondary infections were defined as infections that occurred following COVID-19. RESULTS: Patients with COVID-19 during the Omicron period were older and had more comorbidities. Coinfections were more common in the Omicron period than in the pre-Omicron period (44.4% [100/225] versus 0.8% [2/257], respectively, p < 0.001), and the mean DOT of antibiotics for CAIs was significantly increased in the Omicron period (from 3.60 to 17.84, p < 0.001). Secondary infection rate tended to be higher in the Omicron period (p = 0.097). Mean DOT of antibiotics for HAIs were appeared to be lower in the COVID-19 ward than in the general ward (pre-Omicron, 3.33 versus 6.37, respectively; Omicron, 3.84 versus 5.22, respectively). No multidrug-resistant gram-negative organisms were isolated in the COVID-19 ward. CONCLUSION: Antibiotic use for CAIs was limited in the pre-Omicron period but increased in the Omicron period because of a high coinfection rate on admission. With the antimicrobial stewardship, excessive use of antibiotics for HAIs was avoided in the COVID-19 ward during both periods.

Clinical features of pasteurellosis without an animal bite or scratch in comparison with bite/scratch pasteurellosis.

Pasteurellosis is a common zoonotic infection that occurs after an animal bite or scratch (B/S). We compared the clinical features of six patients with non-B/S pasteurellosis with those of 14 patients with B/S infections. Pasteurella multocida was identified with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry in all six non-B/S infections, whereas 13 of the 14 B/S infections were identified with diagnostic kits. The non-B/S infections were pneumonia (n = 3), skin and soft tissue infections (n = 2), and bacteremia (n = 1). Pneumonia occurred in two patients with underlying pulmonary disease, whereas ventilator-associated pneumonia developed in one patient with cerebral infarction. Pasteurella multocida was isolated from a blood specimen and nasal swab from a patient with liver cirrhosis (Child-Pugh class C) and diabetes. Cellulitis developed in one patient with diabetes and normal-pressure hydrocephalus, who had an open wound following a fall, and in one patient with diabetes and a foot ulcer. Three patients with non-B/S infections had no pet and no episode of recent animal contact. The rate of moderate-to-severe comorbidities was significantly higher in patients with non-B/S infections than in those with B/S infections (100% and 14.3%, respectively, p < 0.001). In conclusion, non-B/S infections can develop in patients with chronic pulmonary disease, invasive mechanical ventilation, or open wounds, or who are immunocompromised, irrespective of obvious animal exposure. In contrast to B/S infections, non-B/S pasteurellosis should be considered opportunistic.

Judicious ending of isolation based on reverse transcription-polymerase chain reaction (RT-PCR) cycle threshold only for patients with coronavirus disease 2019 (COVID-19) requiring in-hospital therapy for longer than 20 days after symptom onset.

BACKGROUND: For patients with coronavirus disease 2019 (COVID-19) requiring hospitalization, extending isolation is warranted. As a cautious protocol, ending isolation based on polymerase chain reaction cycle threshold (Ct) value was introduced for patients requiring therapy for >20 days after symptom onset. METHOD: We compared a Ct-based strategy using Smart Gene® between March 2022 and January 2023 with a preceding control period (March 2021 to February 2022) when two consecutive negative reverse transcription-polymerase chain reaction tests using FilmArray® were required for ending isolation. Ct was evaluated on day 21, and ending isolation was permitted in patients with Ct ≥ 38. Although patients with Ct 35-37 were transferred to a non-COVID-19 ward, isolation was continued. RESULTS: The duration of stay on a COVID-19 ward in the Ct group was 9.7 days shorter than that in controls. The cumulative number of tests was 3.7 in controls and 1.2 in the Ct group. There was no nosocomial transmission after ending isolation in either group. The number of days from symptom onset to testing was 20.7 ± 2.1 in Ct group, and five patients had Ct < 35, nine Ct 35-37, and 71 Ct ≥ 38. No patients were moderately or severely immunocompromised. Steroid use was an independent risk factor for prolonged low Ct (odds ratio 9.40, 95% confidence interval 2.31-38.15, p = 0.002) CONCLUSIONS: The efficacy of ending isolation based on Ct values could improve bed utilization without the risk of transmission among patients with COVID-19 requiring therapy for >20 days after symptom onset.

Comparison of antibiotic use and antibiotic resistance between a community hospital and tertiary care hospital for evaluation of the antimicrobial stewardship program in Japan.

Assessment of risk-adjusted antibiotic use (AU) is recommended to evaluate antimicrobial stewardship programs (ASPs). We aimed to compare the amount and diversity of AU and antimicrobial susceptibility of nosocomial isolates between a 266-bed community hospital (CH) and a 963-bed tertiary care hospital (TCH) in Japan. The days of therapy/100 bed days (DOT) was measured for four classes of broad-spectrum antibiotics predominantly used for hospital-onset infections. The diversity of AU was evaluated using the modified antibiotic heterogeneity index (AHI). With 10% relative DOT for fluoroquinolones and 30% for each of the remaining three classes, the modified AHI equals 1. Multidrug resistance (MDR) was defined as resistance to ≥ 3 anti-Pseudomonas antibiotic classes. The DOT was significantly higher in the TCH than in the CH (10.85 ± 1.32 vs. 3.89 ± 0.93, p < 0.001). For risk-adjusted AU, the DOT was 6.90 ± 1.50 for acute-phase medical wards in the CH, and 8.35 ± 1.05 in the TCH excluding the hematology department. In contrast, the DOT of antibiotics for community-acquired infections was higher in the CH than that in the TCH. As quality assessment of AU, higher modified AHI was observed in the TCH than in the CH (0.832 ± 0.044 vs. 0.721 ± 0.106, p = 0.003), indicating more diverse use in the TCH. The MDR rate in gram-negative rods was 5.1% in the TCH and 3.4% in the CH (p = 0.453). No significant difference was demonstrated in the MDR rate for Pseudomonas aeruginosa and Enterobacteriaceae species between hospitals. Broad-spectrum antibiotics were used differently in the TCH and CH. However, an increased antibiotic burden in the TCH did not cause poor susceptibility, possibly because of diversified AU. Considering the different patient populations, benchmarking AU according to the facility type is promising for inter-hospital comparisons of ASPs.

Cyclic stretch enhances reorientation and differentiation of 3-D culture model of human airway smooth muscle.

Activation of airway smooth muscle (ASM) cells plays a central role in the pathophysiology of asthma. Because ASM is an important therapeutic target in asthma, it is beneficial to develop bioengineered ASM models available for assessing physiological and biophysical properties of ASM cells. In the physiological condition in vivo, ASM cells are surrounded by extracellular matrix (ECM) and exposed to mechanical stresses such as cyclic stretch. We utilized a 3-D culture model of human ASM cells embedded in type-I collagen gel. We further examined the effects of cyclic mechanical stretch, which mimics tidal breathing, on cell orientation and expression of contractile proteins of ASM cells within the 3-D gel. ASM cells in type-I collagen exhibited a tissue-like structure with actin stress fiber formation and intracellular Ca2+ mobilization in response to methacholine. Uniaxial cyclic stretching enhanced alignment of nuclei and actin stress fibers of ASM cells. Moreover, expression of mRNAs for contractile proteins such as α-smooth muscle actin, calponin, myosin heavy chain 11, and transgelin of stretched ASM cells was significantly higher than that under the static condition. Our findings suggest that mechanical force and interaction with ECM affects development of the ASM tissue-like construct and differentiation to the contractile phenotype in a 3-D culture model.