Epidemiological and comparative genomic analyses of Multidrug-Resistant Acinetobacter baumannii collected between 2020 and 2022 in Liaocheng City, Shandong Province, China

The emergence and prevalence of multidrug-resistant Acinetobacter baumannii (MRAB) poses a huge challenge to clinical treatment. To investigate the genetic and epidemiologic characteristics of MRAB in Liaocheng, China, and to explore potential resistance mechanisms, 56 MRAB strains were collected from the clinical departments of seven hospitals in Liaocheng between 2020 and 2022. Molecular typing, antimicrobial resistance patterns, and epidemiological characteristics were determined by genome sequencing and comparative genome analysis. Sequence type (ST) 540 was the most prevalent ST of the 56 MRAB in Liaocheng, and most strains (92.86%) were grouped into CC92. Core genome multilocus sequence typing subdivided the strains according to the number of allelic differences and could distinguish different outbreaks caused by ST540 isolates in the hospitals. All the isolates harbored blaOXA-23 and blaADC-25, and at least 92.86% of the isolates were resistant to 10 antibiotics. The major MRAB epidemic clone detected in Liaocheng was ST540, which was different from the results reported in other regions in China. Furthermore, several inter-hospital transmissions of ST540 isolates were observed. The findings highlight the urgent need for effective nosocomial infection control measures and the continuous surveillance of ST540 MRAB in Liaocheng

Detection of Aircraft Emissions Using Long-Path Differential Optical Absorption Spectroscopy at Hefei Xinqiao International Airport

Airport emissions have received increased attention because of their impact on atmospheric chemical processes, the microphysical properties of aerosols, and human health. At present, the assessment methods for airport pollution emission mainly involve the use of the aircraft emission database established by the International Civil Aviation Organization, but the emission behavior of an engine installed on an aircraft may differ from that of an engine operated in a testbed. In this study, we describe the development of a long-path differential optical absorption spectroscopy (LP-DOAS) instrument for measuring aircraft emissions at an airport. From 15 October to 23 October 2019, a measurement campaign using the LP-DOAS instrument was conducted at Hefei Xinqiao International Airport to investigate the regional concentrations of various trace gases in the airport’s northern area and the variation characteristics of the gas concentrations during an aircraft’s taxiing and take-off phases. The measured light path of the LP-DOAS passed through the aircraft taxiway and the take-off runway concurrently. The aircraft’s take-off produced the maximum peak in NO2 average concentrations of approximately 25 ppbV and SO2 average concentrations of approximately 8 ppbV in measured area. Owing to the airport’s open space, the pollution concentrations decreased rapidly, the overall levels of NO2 and SO2 concentrations in the airport area were very low, and the maximum hourly average NO2 and SO2 concentrations during the observation period were better than the Class 1 ambient air quality standards in China. Additionally, we discovered that the NO2 and SO2 emissions from the Boeing 737–800 aircraft monitored in this experiment were weakly and positively related to the age of the aircraft. This measurement established the security, feasibility, fast and non-contact of the developed LP-DOAS instrument for monitoring airport regional concentrations as well as NO2 and SO2 aircraft emissions during routine airport operations without interfering with the normal operation of the airport