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BackgroundThe cluster detection of health care–associated infections (HAIs) is crucial for identifying HAI outbreaks in the early stages. ObjectiveWe aimed to verify whether multisource surveillance based on the process data in an area network can be effective in detecting HAI clusters. MethodsWe retrospectively analyzed the incidence of HAIs and 3 indicators of process data relative to infection, namely, antibiotic utilization rate in combination, inspection rate of bacterial specimens, and positive rate of bacterial specimens, from 4 independent high-risk units in a tertiary hospital in China. We utilized the Shewhart warning model to detect the peaks of the time-series data. Subsequently, we designed 5 surveillance strategies based on the process data for the HAI cluster detection: (1) antibiotic utilization rate in combination only, (2) inspection rate of bacterial specimens only, (3) positive rate of bacterial specimens only, (4) antibiotic utilization rate in combination + inspection rate of bacterial specimens + positive rate of bacterial specimens in parallel, and (5) antibiotic utilization rate in combination + inspection rate of bacterial specimens + positive rate of bacterial specimens in series. We used the receiver operating characteristic (ROC) curve and Youden index to evaluate the warning performance of these surveillance strategies for the detection of HAI clusters. ResultsThe ROC curves of the 5 surveillance strategies were located above the standard line, and the area under the curve of the ROC was larger in the parallel strategy than in the series strategy and the single-indicator strategies. The optimal Youden indexes were 0.48 (95% CI 0.29-0.67) at a threshold of 1.5 in the antibiotic utilization rate in combination–only strategy, 0.49 (95% CI 0.45-0.53) at a threshold of 0.5 in the inspection rate of bacterial specimens–only strategy, 0.50 (95% CI 0.28-0.71) at a threshold of 1.1 in the positive rate of bacterial specimens–only strategy, 0.63 (95% CI 0.49-0.77) at a threshold of 2.6 in the parallel strategy, and 0.32 (95% CI 0.00-0.65) at a threshold of 0.0 in the series strategy. The warning performance of the parallel strategy was greater than that of the single-indicator strategies when the threshold exceeded 1.5. ConclusionsThe multisource surveillance of process data in the area network is an effective method for the early detection of HAI clusters. The combination of multisource data and the threshold of the warning model are 2 important factors that influence the performance of the model.

BackgroundThere is a need to develop innovative and accessible dyadic interventions that provide male couples with the behavioral skills to manage the risk of HIV transmission within their relationship. ObjectiveWe conducted a pilot randomized controlled trial (RCT) to assess the feasibility and acceptability of the electronic health (eHealth) HIV prevention toolkit intervention to encourage seroconcordant negative male couples in the United States to establish and adhere to a sexual agreement (SA). MethodsEligible, consented couples were randomly assigned to the intervention or education control and followed up for 6 months, with assessments occurring every 3 months after baseline. Acceptability items were assessed at both follow-up assessments. Descriptive and comparative statistics summarized cohort characteristics, relationship dynamics, and SA outcomes for the entire cohort and by trial arm. To examine the association between couples’ relationship dynamics and their establishment of an SA over time and by trial arm, multilevel logistic regression analyses were performed with a random intercept to account for correlations of repeated measurements of relationship dynamics at months 3 and 6; the odds ratio (OR) of establishment of an SA and the corresponding 95% confidence interval were then reported. ResultsOverall, 7959 individuals initiated screening. Reasons for individual ineligibility varied. An electronic algorithm was used to assess couple-level eligibility, which identified 1080 ineligible and 266 eligible dyads. Eligible couples (n=149) were enrolled in the pilot RCT: 68 received the intervention and 81 received the education control. Retention was 71.5% (213/298 partnered men) over the 6 months. Participants reported high acceptability of the intervention along with some areas for improvement. A significantly higher proportion of couples who received the intervention established an SA at 6 months compared with those who received the education control (32/43, 74% vs 27/50, 54%; P=.05). The OR of establishing an SA for couples in the intervention versus those in the control condition was greater than 2 when controlling for a number of different relationship dynamics. In addition, the odds of establishing an SA increased by 88% to 322% for each unit increase in a variety of averaged relationship dynamic scores; the opposite result was found for dynamics of stigma. Differences between trial arms for SA type and adherence were nonsignificant at each assessment. However, changes in these 2 SA aspects were noted over time. The average number of items couples included in their SA was 18, and about one-fourth to one-third of couples included HIV prevention items. ConclusionsThe findings demonstrate strong evidence for the acceptability and feasibility of the eHealth toolkit as a brief, stand-alone, couples-based HIV prevention intervention. These findings support the need to update the toolkit and evaluate it in a larger clinical trial powered for efficacy. Trial RegistrationClinicalTrials.gov NCT02494817; http://clinicaltrials.gov/ct2/show/NCT02494817

The aim of this study was to determine the interrelationship between umami peptides and microorganisms in traditional fermented sea bass and to explore the inhibitory effect of umami peptides on bitterness. Thirty-eight umami peptides were identified and predicted from traditional fermented sea bass using peptidomics combined with machine learning techniques, and the results of macrogenomic annotation indicated that a total of 51 microbial genera and 7 proteases were involved. Rhodococcus, Staphylococcus, Clostridium, Thiothrix, Pseudomonas and Achromobacter might play key roles in the formation of the flavor peptides in fermented sea bass. Molecular docking results showed that umami peptides EEEVVEEVE, DEEYPDL and DEEYPDLS could bind to the bitter taste receptor (TAS2R14), and their binding cavities were consistent. The interaction between the three peptides and TAS2R14 was mainly through hydrogen bonding, and the key binding sites of these peptides were SER265, SER69, SER65 and THR86. The electronic tongue results showed that all three umami peptides had a significant inhibitory effect on bitterness. This study provides a new idea to study the interaction between fish-derived umami peptides and bitterness.

In this study, the effects of different curing methods (static treatment, ultrasonic treatment, ultrasonic treatment combined with tumbling, vacuum tumbling and atmospheric pressure tumbling) on the textural properties, water retention and flavor quality of low-salt pre-prepared sea bass were investigated using texture analysis, scanning electron microscopy (SEM), liquid chromatography (LC) and gas chromatography-mass spectrometry (GC-MS). The results showed that tumbling alone and combined with ultrasonic treatment both significantly increased the marinade absorption rate and the mass transfer rate of sodium ion (P < 0.05), and the marinade absorption rate was 15.07% in the atmospheric pressure tumbling group, which was accompanied by reduced hardness and chewiness of fish meat. Organoleptic analysis showed that the fish treated by ultrasonic-assisted tumbling and tumbling was soft in texture, uniformly salty, and had less odor. In addition, both tumbling treatments significantly increased the total free amino acid content (P < 0.05), and the total free amino acid content was 7.395 mg/g in the atmospheric pressure tumbling group, which was about 1.24 times higher than that of the static treatment. A total of 65 volatile flavor compounds were detected across all treatment groups, among which, the contents of alcohols, esters and aromatic compounds were significantly higher (P < 0.05) in the tumbling treatment and ultrasonic-assisted tumbling groups than in the other treatment groups, suggesting that tumbling, irrespective of whether combined with ultrasonic or not, contributed to the formation of flavor substances. However, single tumbling marination showed poor water retention and water-holding capacity, and excessive tumbling might have adverse effects on fish texture. Therefore, ultrasonic-assisted tumbling was more suitable for the intensive processing of sea bass.

The contamination status of cold resistant Morganella psychrotolerans in commercially available aquatic products was investigated, and the generation of histamine by its isolates was explored. A total of 100 samples of commercially available fish from Guangdong province were surveyed. The results revealed a widespread distribution of M. psychrotolerans with a contamination rate of 34%. The contamination rates for red-fleshed and white-fleshed fish were 35.9% and 27.3%, respectively. Specifically, the mackerel samples had a contamination rate of 38.24%, and the tuna samples had a contamination rate of 29.41% among all positive samples. Sixteen strains of M. psychrotolerans were isolated from the positive samples, and all isolates produced histamine levels exceeding 1 000 mg/L after 48 h incubation at 20 ℃. Notably, isolate 1 showed higher histamine-producing capacity than the type strain. Although the two strains exhibited no significant differences in growth curves at varying temperatures (4 and 20 ℃), their histamine-producing capacities were different. After 10 days of culture at 4 ℃, histamine production was higher by isolate 1 than the type strain, while the opposite result was observed after 60 h of culture at 20 ℃. These findings offer crucial theoretical support for addressing the problem of histamine accumulation in cold chain aquatic products.

In this study, the effects of five common oxidative decontaminating agents (H2O2 solution, ClO2 solution, NaClO solution, ozonated water and slightly acidic electrolytic water) on the bacterial decontamination of tilapia fillets and their influence on the texture, color and myofibrillar protein (MP) oxidation in tilapia fillets were investigated. The results showed that a decontamination rate of 80% was attained by immersion in 1 500 mg/L H2O2 solution for 8 min, 200 mg/L ClO2 solution for 10 min, 200 mg/L NaClO solution for 10 min, 9 mg/L ozonated water for 10 min, or 30 mg/L slightly acidic electrolytic water for 20 min. Compared with the control group, treatment with decontaminating agents increased the hardness and L* value of tilapia fillets, decreased the a* value, MP content, total sulfhydryl group content, and raised the content of carbonyl groups and the amount of surface hydrophobic groups. The degree of protein denaturation in the slightly acidic electrolytic water and NaClO solution groups was the highest; the fluorescence intensity of MP was decreased after decontamination treatments, with the greatest decrease being found in the slightly acidic electrolytic water-treated group; the relative contents of α-helix and β-turn in MP were decreased, while the relative contents of β-fold and random coil were increased, with the most significant changes in the secondary structure of MP being observed in the slightly acidic electrolytic water-treated group (P < 0.05). MP underwent degradation to different extents, and the degradation degree of the slightly acidic electrolytic water group was higher than that of the other treatment groups. In summary, the oxidation of fish MP occurred to varying degrees after oxidative decontamination treatments, with slightly acidic electrolytic water treatment having the strongest oxidative effect.

In this study, the effect of fermentation with Bacillus subtilis B-2, a salt-tolerant strain capable of producing high yield of protease, on the microbial community and the contents of biogenic amines and amino acid nitrogen (AAN) during the fermentation of low-salt fish sauce. The results of high-throughput 16S rRNA gene sequencing showed that fermentation with B-2 reduced the richness and evenness of the microbial community, Bacillus was dominant throughout the fermentation process and the abundance of spoilage microorganisms significantly decreased. B-2 significantly inhibited the formation of histamine, putrescine, cadaverine, and tyramine, and their contents at the end of fermentation decreased by 25.9%, 35.6%, 23.6% and 9.3%, respectively, compared with those in naturally fermented fish sauce. The content of AAN in low-salt fish sauce was significantly improved by inoculated fermentation, reaching 1.23 g/100 mL after 15 days of fermentation, which was significantly higher than that of naturally fermented fish sauce (0.79 g/100 mL). The correlation network map showed that the decrease in the abundance of Brevibacterium, Dietzia, Paracoccus, Aequorivita, and Brachybacterium was the major reason for the decrease in microbial diversity at the late stage of fermentation of naturally fermented fish sauce. The abundance of Stenotrophomonas showed a significantly positive correlation with the contents of many biogenic amines in naturally fermented and B-2 fermented fish sauce, suggesting its important role in the formation of biogenic amines in low-salt fish sauce. Comparative analysis of the microbial community and quality attributes at the end of fermentation showed that the metabolism of B-2 was the main reason for the decrease in the species and abundance of spoilage microorganisms, the increase in AAN content, and the decrease in the contents of key biogenic amines. B. subtilis B-2 is expected to be developed as a special fermentation starter for fish sauce to improve the quality and safety of rapidly fermented low-salt fish sauce.