Improvement of glycolysis metabolic capacity by exercise training under local muscle hypoxia in a cold water environment / 体力科学

This study investigated the physiological responses and effects of exercise training under hypoxic conditions at the skeletal muscle level induced by reducing muscle temperature in cold water environment. Participants were divided into two intervention groups, cooling and control conditions, according to the water temperature of 15°C and 33°C where the training were conducted in. Eight participants in each group performed submaximal cycling exercise in the water for 30 minutes at the lactate threshold (LT) intensity, three times a week for four weeks (12 sessions). LT intensity was assessed at pre- and post-intervention in a 33°C water temperature environment. A progressive load cycling test was performed on land to assess maximal oxygen uptake (VO2max) and Wingate test was conducted to measure anaerobic power. In the cooling group, working muscle deoxygenation increased during submaximal and maximal exercise, suggesting an improvement in the muscle oxygen extraction capacity. However, no effects on aerobic capacity such as VO2max or LT intensity were observed. The improvement in mean power and time to peak during the Wingate test in the cooling group indicated that LT intensity exercise training in a cold water environment would increase anaerobic power.

Distribution characteristics of antibiotic resistance genes in the domestic water of residents in Haimen， Jiangsu Province / 上海预防医学

ObjectiveAntibiotic resistance genes （ARGs） have received wide attention all over the world. The purpose of this study was to explore the bacterial community structure， the types and levels of antibiotic resistance genes in a water body in east China， and to compare and analyze the characteristics of microbial species distribution and antibiotic resistance gene distribution in various water environments. MethodsA total of 10 households in Haimen City， Jiangsu Province were selected and their surrounding water environment samples were collected. 21 water samples including river water （4）， Mingou water （9） and well water （8） were collected for metagenomics sequencing， assembled with MetaWRAP， annotated with CARD database， and analyzed with R software. ResultsIn various water bodies， the dominant bacteria phyla was Proteobacteria， the dominant bacteria genera were Deuterostomia， Pseudomonas， Flavobacteriales and Streptomycetaceae. The ARGs annotated were mainly composed of quinolones， aminoglycosides， macrolides and beta-lactams antibiotic resistance genes. The top four relative abundance of resistance genes were macB， RanA， evgS and TxR， The average absolute abundance and expression of resistance genes in well water and Mingou water were higher than those in river water. ConclusionMultiple ARGs are detected to varying degrees in well water， river water， and Mingou water bodies， and the expression of resistance genes in well water and Mingou water bodies is higher than that in river water bodies， possibly due to human production and living activities.

Contamination status and molecular typing of Legionella pneumophila in artificial water environment in Shanghai hospitals from 2019 to 2020 / 环境与职业医学

Background The incidence of Legionnaires' disease is increasing globally and artificial water environment is becoming a common source of outbreaks. Molecular typing techniques can help prevent and control Legionella. Objective To understand the molecular epidemiological characteristics of Legionella pneumophila in artificial water environment of Shanghai hospitals, and provide a scientific basis for the prevention and control of Legionnaires' disease. Methods Water samples were collected from artificial water environment in 14 hospitals from May to October each year from 2019 to 2020 in Shanghai. A total of 984 water samples were collected from 8 Grade-A tertiary hospitals and 6 non-Grade-A tertiary hospitals, including 312 samples of cooling water, 72 samples of chilled water, and 600 samples of tap water. The water samples were isolated and serotyped for Legionella pneumophila and preserved, and the positive rate of Legionella pneumophila in the samples was used as an indicator of contamination. The preserved strains were resuscitated and 81 surviving strains were obtained for pulsed field gel electrophoresis (PFGE) typing analysis. Results A total of 124 Legionella pneumophila positive water samples were detected, with a positive rate of 12.60%. The positive rate was higher in the Grade-A tertiary hospitals (16.54%, 87/526) than in the non-Grade-A tertiary hospitals (8.08%, 37/458) (χ2=15.91, P<0.001). The positive rate of cooling water (23.40%) was the highest among different types of water samples, and the difference was statistically significant (χ2=61.19, P<0.001). The difference in positive rate of tap water was statistically significant among different hospital departments (χ2=11.37, P<0.05). The positive rate in 2019 (15.06%) was higher than that in 2020 (9.84%) (χ2=6.23, P<0.05). From May to October, August had the highest annual average positive rate (16.46%) and October had the lowest (8.54%), but the difference in positive rates among months was not statistically significant (χ2=5.39, P=0.37). The difference in positive rate among districts was statistically significant (χ2=24.88, P<0.001). A total of 131 strains of Legionella pneumophila were isolated, with serotype 1 (80.15%, 105/131) predominating. Among the 81 surviving strains of Legionella pneumophila subjected to PFGE typing, the band-based similarity coefficients ranged from 41.30% to 100%. Among the 29 PFGE band types (S1-S29) recorded, each band type included 1-10 strains, and S28 was the dominant band type. Four clusters (I-IV) of PFGE band types were identified, accounting for 66.67% (54/81) of all strains and containing 13 band types. Conclusion Legionella pneumophila contamination is present in the artificial water environment of hospitals in Shanghai from 2019 to 2020, and the contamination in tap water deserves attention. The detected serotype of Legionella pneumophila is predominantly type 1, and PFGE typing reveals the presence of genetic polymorphism. Therefore, the monitoring and control of Legionella pneumophila in hospital artificial water environment should be strengthened.

Domestic wastewater treatment plants as sources of macrolide-lincosamide-streptogramin B- and penicillin-resistant Staphylococcus aureus in Brazil / Plantas de tratamiento de aguas residuales domésticas como fuentes de Staphylococcus aureus resistente a macrólidos-lincosamida-estreptogramina B- y penicilina en Brasil / Estações de tratamento de águas residuais domésticas como fontes de Staphylococcus aureus resistente a macrolídeo-lincosamida-estreptograma e B- e penicilina no Brasil

SUMMARY Staphylococcus aureus is one of the main bacteria that affect human health. Its reduced susceptibility to beta-lactam antibiotics has driven the clinical use of macrolides and lincosamides. However, the presence of macrolide-lincosamide-streptogramin B (MLSB)-resistant S. aureus strains is increasingly common. Wastewater treatment plants (WWTPs) are the main anthropogenic source of resistance determinants. However, few studies have assessed the importance of this environment on the dissemination of MLSB-resistant S. aureus strains. Thus, we aimed to evaluate the impact of a domestic WWTP on the resistance to MLSB and penicillin in S. aureus in southeast Brazil. Of the 35 isolates tested, 40.6% were resistant to penicillin. Resistance to erythromycin (8.6%) and quinolones (2.8%) was less common. Despite the low rate of resistance to clindamycin (2.8%), many isolates showed reduced susceptibility to this antibiotic (57.1%). Regarding the resistance phenotypes of staphylococci isolates, inducible MLSB resistance (D-test positive) was found in two isolates. In addition, 27 S. aureus isolates showed the ability to produce penicillinase. In this article, we report for the first time the importance of WWTPs in the dissemination of MSLB resistance among S. aureus from southeast Brazil.

RESUMEN Staphylococcus aureus es una de las principales bacterias que afectan la salud humana. Su susceptibilidad reducida a los antibióticos betalactámicos ha impulsado el uso clínico de macrólidos y lincosamidas. Sin embargo, la presencia de cepas resistentes a macrólido-lincosamida-estreptogramina B (MLSB) de S. aureus es cada vez más común. Las plantas de tratamiento de aguas residuales (PTAR) son la principal fuente antropogénica de determinantes de resistencia. Sin embargo, pocos estudios han evaluado la importancia de este entorno en la diseminación de cepas de S. aureus resistentes a MLSB. Nuestro objetivo fue evaluar el impacto de una PTAR doméstica en MLSB y la resistencia a la penicilina en S. aureus en el sureste de Brasil. De los 35 aislamientos analizados, el 40,6% eran resistentes a la penicilina. La resistencia a la eritromicina (8,6%) y quinolonas (2,8%) fue menos común. A pesar de la baja tasa de resistencia a la clindamicina (2,8%), muchos aislamientos mostraron sensibilidad reducida a este antibiótico (57,1%). Con respecto a los fenotipos de resistencia de los aislamientos de estafilococos, la resistencia inducible a MLSB (prueba D positiva) se encontró en dos aislamientos. Además, 27 aislamientos de S. aureus mostraron la capacidad de producir penicilinasa. En este artículo informamos, por primera vez, la importancia de las PTAR en la difusión de la resistencia a MSLB entre S. aureus del sureste de Brasil.

RESUMO O Staphylococcus aureus é uma das principais bactérias que afetam a saúde humana. Sua reduzida suscetibilidade aos antibióticos beta-lactâmicos tem impulsionado o uso clínico de macrolídeos e lincosamidas. No entanto, a presença de cepas de S. aureus resistentes a macrolídeo-lincosamida-estreptogramina B (MLSB) é cada vez mais comum. As estações de tratamento de esgoto (ETEs) são a principal fonte antropogênica de determinantes de resistência. No entanto, poucos estudos avaliaram a importância desse ambiente na disseminação de cepas de S. aureus resistentes ao MLSB. Assim, nosso objetivo foi avaliar o impacto de uma ETE doméstico na resistência ao MLSB e à penicilina em S. aureus no sudeste do Brasil. Dos 35 isolados testados, 40,6% eram resistentes à penicilina. Resistência à eritromicina (8,6%) e quinolonas (2,8%) foi menos comum. Apesar da baixa taxa de resistência à clindamicina (2,8%), muitos isolados apresentaram sensibilidade reduzida a esse antibiótico (57,1%). Em relação aos fenótipos de resistência dos isolados de estafilococos, a resistência induzível ao MLSB (D-teste positivo) foi encontrada em dois isolados. Além disso, 27 isolados de S. aureus mostraram a capacidade de produzir penicilinase. Neste artigo relatamos pela primeira vez a importância das ETEs na disseminação da resistência do MSLB entre S. aureus do sudeste do Brasil.

Two water environment adaptation models enhance motor behavior and improve the success of the lactate minimum test in swimming rats

Abstract AIMS This study was designed to investigate the effects of 14 water environment adaptation days on motor behavior and physiological condition of swimming rats. METHODS Sixty male Wistar rats were divided into four groups-baseline (Bl) and control (Co) groups-which did not perform the water environment adaptation; and sub (SubAnT) and (SupraAnT) anaerobic threshold groups, which performed 14 water environment adaptation days with sub or supra anaerobic threshold progressive loads (from the tenth day), respectively. The climbing-swimming prevalence (i.e. motor behavior) was analyzed during the water environment adaptation days. Lactate minimum test (LMT) parameters and muscular/hepatic glycogen content in addition to serum creatine kinase were also measured. RESULTS Animals from SubAnT and SupraAnT groups presented a lower climbing-swimming pattern throughout the extent of the experiment (p=0.000), especially after the 5th session. These results were achieved without an improvement in the LMT results or glycogen/creatine kinase. In addition, improvements of 26.6% and 25% for the LMT success rate (i.e. LMT reliability) were obtained only for SubAnT and SupraAnT animals. CONCLUSION Overall, we demonstrated that a water environment adaptation period is necessary for lowering the climbing-swimming pattern without physiological improvement.(AU)

Underwater digital image measurement using lens sleeves / 医用生物力学

Objective To explore the mechanical testing technique suitable for biological materials under water environment. Methods Based on digital image correlation (DIC) method, the unique lens sleeves which can avoid the distortion caused by underwater photography was designed, and this technique was applied to determining mechanical properties of the fish scales. Results The experiment on translation of the water sink indicated that the use of the designed lens sleeves could effectively reduce errors for underwater measurement with high precision; the mechanical testing on fish scales showed that different regions of the fish scales had obviously different mechanical properties, but the differences induced by regions of the dehydrated fish scales were significantly reduced. Conclusions The designed lens sleeves in this study can be applied to image acquisition effectively, and determination of mechanical properties of the biological materials under water environment was achieved using DIC method.