Synergistic interactions in multispecies biofilm combinations of bacterial isolates recovered from diverse food processing industries

Most biofilms within the food industry are formed by multiple bacterial species which co-exist on surfaces as a result of interspecies interactions. These ecological interactions often make these communities tolerant against antimicrobials. Our previous work led to the identification of a large number (327) of highly diverse bacterial species on food contact surfaces of the dairy, meat, and egg industries after routine cleaning and disinfection (C&D) regimes. In the current study, biofilm-forming ability of 92 bacterial strains belonging to 26 genera and 42 species was assessed and synergistic interactions in biofilm formation were investigated by coculturing species in all possible four-species combinations. Out of the total 455 four-species biofilm combinations, greater biofilm mass production, compared to the sum of biofilm masses of individual species in monoculture, was observed in 34 combinations. Around half of the combinations showed synergy in biofilm mass > 1.5-fold and most of the combinations belonged to dairy strains. The highest synergy (3.13-fold) was shown by a combination of dairy strains comprising Stenotrophomonas rhizophila, Bacillus licheniformis, Microbacterium lacticum, and Calidifontibacter indicus. The observed synergy in mixed biofilms turned out to be strain-specific rather than species-dependent. All biofilm combinations showing remarkable synergy appeared to have certain common species in all combinations which shows there are keystone industry-specific bacterial species which stimulate synergy or antagonism and this may have implication for biofilm control in the concerned food industries

Predicting Divorce Prospect Using Ensemble Learning:Support Vector Machine, Linear Model, and Neural Network

A divorce is a legal step taken by married people to end their marriage. It occurs after a couple decides to no longer live together as husband and wife. Globally, the divorce rate has more than doubled from 1970 until 2008, with divorces per 1,000 married people rising from 2.6 to 5.5. Divorce occurs at a rate of 16.9 per 1,000 married women. According to the experts, over half of all marriages ends in divorce or separation in the United States. A novel ensemble learning technique based on advanced machine learning algorithms is proposed in this study. The support vector machine (SVM), passive aggressive classifier, and neural network (MLP) are applied in the context of divorce prediction. A question-based dataset is created by the field specialist. The responses to the questions provide important information about whether a marriage is likely to turn into divorce in the future. The cross-validation is applied in 5 folds, and the performance results of the evaluation metrics are examined. The accuracy score is 100%, and Receiver Operating Characteristic (ROC) curve accuracy score, recall score, the precision score, and the F1 accuracy score are close to 97% confidently. Our findings examined the key indicators for divorce and the factors that are most significant when predicting the divorce

Efficacy of Hydroxychloroquine and Tocilizumab in Patients With COVID-19: Single-Center Retrospective Chart Review.

BACKGROUND: During the initial phases of the COVID-19 pandemic, there was an unfounded fervor surrounding the use of hydroxychloroquine (HCQ) and tocilizumab (TCZ); however, evidence on their efficacy and safety have been controversial. OBJECTIVE: The purpose of this study is to evaluate the overall clinical effectiveness of HCQ and TCZ in patients with COVID-19. We hypothesize that HCQ and TCZ use in these patients will be associated with a reduction in in-hospital mortality, upgrade to intensive medical care, invasive mechanical ventilation, or acute renal failure needing dialysis. METHODS: A retrospective cohort study was performed to determine the impact of HCQ and TCZ use on hard clinical outcomes during hospitalization. A total of 176 hospitalized patients with a confirmed COVID-19 diagnosis was included. Patients were divided into two comparison groups: (1) HCQ (n=144) vs no-HCQ (n=32) and (2) TCZ (n=32) vs no-TCZ (n=144). The mean age, baseline comorbidities, and other medications used during hospitalization were uniformly distributed among all the groups. Independent t tests and multivariate logistic regression analysis were performed to calculate mean differences and adjusted odds ratios with 95% CIs, respectively. RESULTS: The unadjusted odds ratio for patients upgraded to a higher level of care (ie, intensive care unit) (OR 2.6, 95% CI 1.19-5.69; P=.003) and reductions in C-reactive protein (CRP) level on day 7 of hospitalization (21% vs 56%, OR 0.21, 95% CI 0.08-0.55; P=.002) were significantly higher in the TCZ group compared to the control group. There was no significant difference in the odds of in-hospital mortality, upgrade to intensive medical care, need for invasive mechanical ventilation, acute kidney failure necessitating dialysis, or discharge from the hospital after recovery in both the HCQ and TCZ groups compared to their respective control groups. Adjusted odds ratios controlled for baseline comorbidities and medications closely followed the unadjusted estimates. CONCLUSIONS: In this cohort of patients with COVID-19, neither HCQ nor TCZ offered a significant reduction in in-hospital mortality, upgrade to intensive medical care, invasive mechanical ventilation, or acute renal failure needing dialysis. These results are similar to the recently published preliminary results of the HCQ arm of the Recovery trial, which showed no clinical benefit from the use of HCQ in hospitalized patients with COVID-19 (the TCZ arm is ongoing). Double-blinded randomized controlled trials are needed to further evaluate the impact of these drugs in larger patient samples so that data-driven guidelines can be deduced to combat this global pandemic

Is it time for microbiome-based therapies in viral infections?

Infectious diseases related to viruses, as well as bacterial pathogens, abound in all parts of the world, burdening health and economy. Thus, there is a dire need to find new prevention and treatment strategies to improve clinical practices related to viral infections. Human gut contains trillions of bacteria which have regulatory roles in immune development, homeostasis, and body metabolism. Today, it is difficult to find any prominent viral infection that hasn’t had any link with the human gut microbiota. In this opinion-based review article, I argued the significance of manipulating human gut microbiota as novel therapeutics through probiotics or FMT in alleviating complexities related to viral infections, and pinpointed bottlenecks involved in this research

Dairy strains of Anoxybacillus flavithermus inhibit lipase production by Geobacillus stearothermophilus

In this study, we demonstrated lipase inhibition in two genetically distinct dairy strains of Geobacillus stearothermophilus caused by two dairy strains of Anoxybacillus flavithermus as a result of their growth in coculture, where no effect on the growth of G. stearothermophilus strains was noted. Further investigation showed that cell-free supernatant (CFS) of A. flavithermus strains has potential to completely inhibit bacterial ability to produce lipases, rather than affecting the activity of lipases, by all strains of G. stearothermophilus by an unknown mechanism and possibly due to the substance that became completely inactivated after heating the CFS at 100 °C for 30 and 60 min. The same lipase inhibition effect of CFS from the A. flavithermus strains was confirmed in Pseudomonas aeruginosa ATCC 10145 as well. This study reports a novel process, yet unknown, by which A. flavithermus strains are able to inhibit lipase production in two distantly related species

New trends in photodynamic inactivation (PDI) combating biofilms in the food industry—A review

Biofilms cause problems in the food industry due to their persistence and incompetent hygiene processing technologies. Interest in photodynamic inactivation (PDI) for combating biofilms has increased in recent years. This technique can induce microbial cell death, reduce cell attachment, ruin biofilm biomolecules and eradicate structured biofilms without inducing microbial resistance. This review addresses microbial challenges posed by biofilms in food environments and highlights the advantages of PDI in preventing and eradicating microbial biofilm communities. Current findings of the antibiofilm efficiencies of this technique are summarized. Additionally, emphasis is given to its potential mechanisms and factors capable of influencing biofilm communities, as well as promising hurdle strategies

Microbiota of milk powders and the heat resistance and spoilage potential of aerobic spore-forming bacteria

Aerobic spore forming bacteria are a concern to the dairy industry because of their ability to produce heat-resistant spores and heat-stable enzymes; The presence of spores in end products results in non-compliance with spore content specifications and the enzymes may withstand all heat treatments applied during the manufacture of milk powders, causing severe quality defects in the final product leading to reduced shelf life. The factors conferring heat resistance to bacterial spores are related to the spore's macromolecular structure, also to a mobile genetic element involved in the heat resistance of spores. A greater understanding of the microbiota of milk powders, its heat resistance and spoilage potential is needed to develop better strategies to fight with these spore-forming bacteria. Therefore, the current status of the microbiota of milk powders is reviewed. Furthermore, heat resistance and spoilage potential of major milk powder contaminants and the factors affecting these properties are discussed in detail

Isolation and in-vitro probiotic characterization of fructophilic lactic acid bacteria from Chinese fruits and flowers

This study was undertaken to focus on the isolation and probiotic characterization of fructophilic lactic acid bacteria (FLAB) isolated from various flowers and fruits belonging to China. Seventy-three FLAB isolates exhibiting fructose fermentation were grown in 30% fructose media, and only eight isolates showed the capability to grow under such high osmotic pressure. From the above isolates, 16S rRNA gene sequencing revealed two strains as Fructobacillus fructosus, three strains as Lactobacillus kunkeei, two strains as F. pseudoficulneus, and one strain as F. durionis. These strains were characterized subsequently for their carbohydrate metabolism and probiotic potential. In comparison to other isolated FLAB strains, L. kunkeei strains showed the maximum capacity to tolerate various low pH levels and bile acid concentrations together with maximal effects on cholesterol assimilation, antipathogenic activity, and hydrophobicity. The fructophilic strains preferred d-fructose over d-glucose and so these strains have potential for use in cereal fermentation to ameliorate fructose-mediated irritable bowel syndromes

Inhibitory effect of Lactobacillus plantarum metabolites against biofilm formation by Bacillus licheniformis isolated from milk powder products

Process biofilms of Bacillus licheniformis present worldwide problem to the dairy industry because of their relevance to food spoilage and quality issues. In this study, metabolites of Lactobacillus plantarum were found to effectively inhibit biofilms formed by B. licheniformis. The biofilm formation was delayed by 10 h by the addition of L. plantarum cell free supernatant and controlling pH of the medium. Confocal laser scanning microscope images showed that L. plantarum metabolites decreased the number of B. licheniformis cells adhered to stainless steel and glass surfaces. Gel filtration chromatography results showed that B. licheniformis utilized the peptides in the growth medium (tryptic soy broth) with the molecular weights ranging from 613 to 1486 Da, and produced plentiful small peptides with the molecular weights ranging from 181 to 613 Da. Moreover, 3–10 kDa components of L. plantarum ultra-filtrates were proved to significantly inhibit biofilm formation by B. licheniformis. Thus, the metabolites produced by L. plantarum provide a novel approach for the prevention of B. licheniformis biofilms in the dairy industry

Interspecies interactions in dual-species biofilms formed by psychrotrophic bacteria and the tolerance of sessile communities to disinfectants

Biofilms on the surface of food processing equipment act as potential reservoirs of microbial contamination. Bacterial interactions are believed to play key roles in both biofilm formation and antimicrobial tolerance. In this study, Aeromonas hydrophila, Chryseobacterium oncorhynchi, and Pseudomonas libanensis, which were previously isolated from Chinese raw milk samples, were selected to establish two dual-species biofilm models (P. libanensis plus A. hydrophila and P. libanensis plus C. oncorhynchi) on stainless steel at 7°C. Subsequently, three disinfectants, hydrogen peroxide (100 ppm), peracetic acid (100 ppm), and sodium hypochlorite (100 ppm), were used to treat the developed sessile communities for 10 min. Structural changes after exposure to disinfectants were analyzed with confocal laser scanning microscopy. The cell numbers of both A. hydrophila and C. oncorhynchi recovered from surfaces increased when grown as dual species biofilms with P. libanensis. Dual-species biofilms were more tolerant of disinfectants than were each single-species biofilm. Peracetic acid was the most effective disinfectant for removing biofilms, followed by hydrogen peroxide and sodium hypochlorite. The results expand the knowledge of mixed-species biofilms formed by psychrotrophic bacteria and will be helpful for developing effective strategies to eliminate bacterial mixed-species biofilms