Study on the Prevention and Control of Fe and Mn Pollution by Resistant Mixed Bacteria in Simulated Mining Area

By simulating the mining environment, the potential of the selected mixed bacteria (Pseudomonas putida, Lysinibacillus xylanilyticus, Lysinibacillus macroides, Bacillus simplex, Brevibacillus agri) to control Fe and Mn pollutants in mining environment were explored. The results showed that the selected bacteria could inhibit the release of Fe and Mn from ore into the aquifer, and the inhibition effect on Mn was significantly stronger than that on Fe. At the same time, these processes also have a certain degree of impact on the external environment, including the gradual increase of pH, the gradual decrease of oxidation-reduction potential, and the decrease of dissolved oxygen concentration. The changes of these external environmental factors will once again directly affect the degradation and immobilization of Fe and Mn. The selected mixed bacteria can also enhance the adsorption of free Fe and Mn, improve the adsorption efficiency and capacity of Fe and Mn, and slow down the desorption of Fe and Mn to water.

Fortified Fermented Rice-Acid Can Regulate the Gut Microbiota in Mice and Improve the Antioxidant Capacity

The study aimed to explore the effects of fortified fermented rice-acid on the antioxidant capacity of mouse serum and the gut microbiota. Hair characteristics, body mass index, intestinal villus height, intestinal crypt depth, serum antioxidant capacity, and gut microbiota of mice were first measured and the correlation between the antioxidant capacity of mouse serum and the gut microbiota was then explored. The mice in the lactic acid bacteria group (L-group), the mixed bacteria group (LY-group), and the rice soup group (R-group) kept their weight well and had better digestion. The mice in the L-group had the better hair quality (dense), but the hair quality in the R-group and the yeast group (Y-group) was relatively poor (sparse). In addition, the inoculation of Lactobacillus paracasei H4-11 (L. paracasei H4-11) and Kluyveromyces marxianus L1-1 (K. marxianus L1-1) increased the villus height/crypt depth of the mice (3.043 ± 0.406) compared to the non-inoculation group (R-group) (2.258 ± 0.248). The inoculation of L. paracasei H4-11 and K. marxianus L1-1 in fermented rice-acid enhanced the blood antioxidant capacity of mouse serum (glutathione 29.503 ± 6.604 umol/L, malonaldehyde 0.687 ± 0.125 mmol/L, catalase 15.644 ± 4.618 U/mL, superoxide dismutase 2.292 ± 0.201 U/mL). In the gut microbiota of L-group and LY-group, beneficial microorganisms (Lactobacillus and Blautia) increased, but harmful microorganisms (Candidatus Arthromitus and Erysipelotrichales) decreased. L. paracasei H4-11 and K. marxianus L1-1 might have a certain synergistic effect on the improvement in antibacterial function since they reduced harmful microorganisms in the gut microbiota of mice. The study provides the basis for the development of fortified fermented rice-acid products for regulating the gut microbiota and improving the antioxidant capacity.

88. Effect of an MDR Enterobacterales Screening Tool on Antibiotic Prescribing for Abdominal Infections Caused by Mixed Bacteria

Background Background: Choosing antibiotics for infections caused by mixed Enterobacterales is challenging. Our microbiology lab implemented a multi-drug resistance (MDR) screen for cultures with mixed gram-negative to direct clinicians to use 3rd generation cephalosporins for screen neg. pathogens, and to use broader beta-lactams for screen-pos. pathogens. Here we report the effect of MDR screen on final antibiotic choice. Methods Methods: We retrospectively reviewed cases with abdominal infections caused by mixed bacteria at UNC Medical Center between August and November 2020. Cultures with non-Enterobacteraeles gram negatives were excluded. MDR screen was done by plating mixed Enterobacterales on HardyCHROM™ ESBL agar. Screen-pos. cases were updated “MDR Enterobacterales present” and pathogens were identified with full susceptibilities. Screen-neg. cases were labeled “MDR Enterobacterales not present”. Definitely covering antibiotics were defined by the use of 3rd generation cephalosporins for screen neg. cases, or based on susceptibilities in case of screen pos. organisms or concomitant bacteremia. Possibly covering antibiotics included regimens whose susceptibility could not be predicted based on the screen (e.g., amox/clav or quinolone+metronidazole). Results Results: 51 cases were identified. Median age was 51 years (range 10 to 87). 54.9% were female and 45.1% male. Infections included intra-abdominal abscesses (n =35), perirectal or scrotal abscesses (10), abdominal wound infections (4), perineal necrotizing fasciitis (1), and cholecystitis (1). Sample types were abscess fluid (43), wound purulence (4) or tissue (3). MDR screen was pos. in 7.8%. Antibiotics were adjusted in 17.6% as a result of the screen report. 31.5% of final antibiotics definitely covered the isolated bacteria, 56.9% possibly covered, and 5.9% did not have an active antibiotic. Among screen pos. cases, final antibiotics definitely covered in 75% and possibly in 25%. Conclusion Conclusions: The MDR Enterobacterales screening tool for abdominal infections had limited impact on final antibiotic choice, but was useful when positive. Further directions include assessment of provider understanding of the MDR screen results and investigation of utility of screen in other infection types. Disclosures All Authors: No reported disclosures

Effect of Fermentation Parameters on Natto and Its Thrombolytic Property

Natto is a popular food because it contains a variety of active compounds, including nattokinase. Previously, we discovered that fermenting natto with the combination of Bacillus subtilis GUTU09 and Bifidobacterium animalis subsp. lactis BZ25 resulted in a dramatically better sensory and functional quality of natto. The current study further explored the effects of different fermentation parameters on the quality of natto fermented with Bacillus subtilis GUTU09 and Bifidobacterium BZ25, using Plackett–Burman design and response surface methodology. Fermentation temperature, time, and inoculation amount significantly affected the sensory and functional qualities of natto fermented with mixed bacteria. The optimal conditions were obtained as follows: soybean 50 g/250 mL, triangle container, 1% sucrose, Bacillus subtilis GUTU09 to Bifidobacterium BZ25 ratio of 1:1, inoculation 7%, fermentation temperature 35.5 °C, and fermentation time 24 h. Under these conditions, nattokinase activity, free amino nitrogen content, and sensory score were increased compared to those before optimization. They were 144.83 ± 2.66 FU/g, 7.02 ± 0.69 mg/Kg and 82.43 ± 5.40, respectively. The plate thrombolytic area and nattokinase activity both increased significantly as fermentation time was increased, indicating that the natto exhibited strong thrombolytic action. Hence, mixed-bacteria fermentation improves the taste, flavor, nattokinase activity, and thrombolysis of natto. This research set the groundwork for the ultimate manufacturing of natto with high nattokinase activity and free amino nitrogen content, as well as good sensory and thrombolytic properties.

Identification of Lactic Acid Bacteria in the corn stalk Fermentation by Fluorescence Quantitative PCR

Lactic acid bacteria play an important role in the fermentation of biological feed. In this experiment, Lactobacillus plantarum, Lactobacillus acidophilus, Bifidobacterium longum, Lactobacillus casei and Lactobacillus rhamnosus were used to ferment corn stalk by single and mixed bacteria. The changes of Lactobacillus flora during fermentation were analyzed by fluorescence quantitative PCR. The results showed that the maximum number of lactic acid bacteria appeared on the 7th day of mixed fermentation, and the total bacteria content could be significantly increased by adding five kinds of lactic acid bacteria at the same time, and the number of each bacteria in mixed fermentation was close to that measured by single fermentation, which indicated that these five kinds of lactic acid bacteria could cooperate during fermentation and help to improve the quality of stalk fermented feed.