Effect of Lactobacillus fermentum on beta2 toxin production by Clostridium perfringens

Oral probiotic administration attenuates postexercise inflammation in horses

Probiotics are commonly incorporated into equine diets to impart health and performance benefits; however, peer-reviewed evidence supporting their efficacy in horses is limited. Interestingly, bacteria from the Bacillus genus are gaining interest for their unique ability to impact metabolic, immune, and inflammatory pathways. The objective of this trial was to evaluate a selection of Bacilli for their role in altering the inflammatory response in horses to exercise. Eighteen horses were utilized in a randomized cross-over trial. Horses were randomly assigned to one of 6 starting treatments including a negative and positive control, and groups that received one of 4 probiotics (Bacillus coagulans GBI-30, 6086, Bacillus subtilis-1, Bacillus subtilis-2, or Bacillus amyloliquefaciens) top dressed to their daily ration at a rate of 8 billion CFU/d mixed into dried whey powder. All horses received a similar base diet of grass hay offered at 2.0% of bodyweight daily along with 4.54 kg of a commercially available textured horse feed. Each 3-wk phase of the trial consisted of a 2-wk dietary acclimation followed by a 1-wk exercise challenge and sample collection. Between phases, horses were offered only their base diet. On the day of exercise, horses were offered their 0700 ration and then subjected to a 2-h standardized exercise test. Blood samples were obtained prior to starting exercise and then again at 0, 2, 4, 6, 8, 24, 48, and 72-h postexercise. Horses in the positive control group were administered 0.23 mg/kg BW flunixin meglumine immediately following the 0-h sampling. Samples were analyzed for serum amyloid A (SAA), interleukin-6 (IL-6), and prostaglandin E2 (PGE2) concentrations. Data were evaluated via ANOVA using the MIXED procedure in SAS 9.4. Exercise-induced inflammation as evidenced by SAA, IL-6, and PGE2 increases postexercise. Horses consuming B. coagulans GBI-30, 6086 had reduced production of SAA, IL-6, and PGE2 compared to all other probiotic-fed groups and the negative control (P < 0.001). The positive control successfully ameliorated the postexercise inflammatory response. These data highlight the potential for B. coagulans GBI-30, 6086 to be incorporated into equine rations as a method to support optimal response to exercise or other inflammation-inducing challenges. Additional research is ongoing to elucidate the methodology by which these results occur.

METTL3 Regulates the Inflammatory Response in CPB2 Toxin-Exposed IPEC-J2 Cells through the TLR2/NF-κB Signaling Pathway

Clostridium perfringens beta2 (CPB2) toxin is one of the main pathogenic toxins produced by Clostridium perfringens, which causes intestinal diseases in animals and humans. The N6-methyladenosine (m6A) modification is the most common reversible modification in eukaryotic disease processes. Methyltransferase-like 3 (METTL3) regulates immunity and inflammatory responses induced by the bacterial infections in animals. However, METTL3's involvement in CPB2-treated intestinal porcine epithelial cell line-J2 (IPEC-J2) remains unclear. In the current study, we used methylated RNA immunoprecipitation-quantitative polymerase chain reaction, Western blotting and immunofluorescence assay to determine the role of METTL3 in CPB2-exposed IPEC-J2 cells. The findings revealed that m6A and METTL3 levels were increased in CPB2 treated IPEC-J2 cells. Functionally, METTL3 overexpression promoted the release of inflammatory factors, increased cytotoxicity, decreased cell viability and disrupted tight junctions between cells, while the knockdown of METTL3 reversed these results. Furthermore, METTL3 was involved in the inflammatory response of IPEC-J2 cells by activating the TLR2/NF-κB signaling pathway through regulating TLR2 m6A levels. In conclusion, METTL3 overexpression triggered the TLR2/NF-κB signaling pathway and promoted CPB2-induced inflammatory responses in IPEC-J2 cells. These findings may provide a new strategy for the prevention and treatment of diarrhea caused by Clostridium perfringens.

Intermediate role of gut microbiota in vitamin B nutrition and its influences on human health

Vitamin B consists of a group of water-soluble micronutrients that are mainly derived from the daily diet. They serve as cofactors, mediating multiple metabolic pathways in humans. As an integrated part of human health, gut microbiota could produce, consume, and even compete for vitamin B with the host. The interplay between gut microbiota and the host might be a crucial factor affecting the absorbing processes of vitamin B. On the other hand, vitamin B supplementation or deficiency might impact the growth of specific bacteria, resulting in changes in the composition and function of gut microbiota. Together, the interplay between vitamin B and gut microbiota might systemically contribute to human health. In this review, we summarized the interactions between vitamin B and gut microbiota and tried to reveal the underlying mechanism so that we can have a better understanding of its role in human health.

Efficacy of Two Probiotic Products Fed Daily to Reduce Clostridium perfringens-Based Adverse Health and Performance Effects in Dairy Calves

Clostridium perfringens is a spore-forming, anaerobic bacterium which produces toxins and exoenzymes that cause disease in calves, especially necro-hemorrhagic enteritis-associated diarrhea often resulting in death. Clostridium infections are currently being treated with antibiotics, but even with the prudent administration of antibiotics, there are significant rates of recurrence. Probiotics, an alternative to antibiotics, are commonly employed to prevent clostridial infections. The objectives of our study were to demonstrate that two commercially available products, when used as daily, direct-fed microbials, are effective in reducing adverse effects of an experimentally induced C. perfringens infection in dairy calves. We conducted a single site efficacy study with masking using a randomized design comprising 10 calves allocated to 3 treatment groups (probiotic 1, probiotic 2, and control). The procedures such as general health scores, body weight, blood samples, and fecal sample collections were done followed by experimental challenge of calves with C. perfringens. Daily feeding of L. animalis LA51 and P. freudenreichii PF24 without or with Bacillus lichenformis CH200 and Bacillus subtilis CH201, before, during and after an oral challenge of C. perfringens significantly reduced the incidence and severity of diarrhea while improving general impression and appearance scores of calves. Most notably, survival of calves in the two probiotic-fed groups was significantly higher than for control calves and further substantiates the potential economic and health benefits of feeding effective probiotics.

Probiotics as Alternatives to Antibiotics for the Prevention and Control of Necrotic Enteritis in Chickens

Necrotic enteritis (NE) in poultry is an economically important disease caused by Clostridium perfringens type A bacteria. A global trend on restricting the use of antibiotics as feed supplements in food animal production has caused a spike in the NE incidences in chickens, particularly in broiler populations. Amongst several non-antibiotic strategies for NE control tried so far, probiotics seem to offer promising avenues. The current review focuses on studies that have evaluated probiotic effects on C. perfringens growth and NE development. Several probiotic species, including Lactobacillus, Enterococcus, Bacillus, and Bacteroides bacteria as well as some yeast species have been tested in chickens against C. perfringens and NE development. These findings have shown to improve bird performance, reduce C. perfringens colonization and NE-associated pathology. The underlying probiotic mechanisms of NE control suggest that probiotics can help maintain a healthy gut microbial balance by modifying its composition, improve mucosal integrity by upregulating expression of tight-junction proteins, and modulate immune responses by downregulating expression of inflammatory cytokines. Collectively, these studies indicate that probiotics can offer a promising platform for NE control and that more investigations are needed to study whether these experimental probiotics can effectively prevent NE in commercial poultry operational settings.

Pilot Study on Alteration of LA-MRSA Status of Pigs during Fattening Period on Straw Bedding by Two Types of Cleaning

In countries with professional pig husbandry in stables, the prevalence of livestock-associated (LA) methicillin-resistant Staphylococcus aureus (MRSA) on farms has remained high or has further increased in recent years. Simple measures to reduce LA-MRSA among pigs have not yet been successfully implemented. The aim of this pilot study is twofold: first, to examine how the LA-MRSA status of LA-MRSA positive fattening pigs at the date of housing changes over the fatting period on straw bedding and, second, whether this change could be influenced by the quality of cleaning and disinfection (C&D). For this purpose, 122 animals are individually tested for LA-MRSA carriage at five sequential time points comparing pigs housed on a farm using straw bedding plus C&D (n = 59) vs. straw bedding plus simple cleaning (n = 63). At the time of housing, all animals in both groups are LA-MRSA positive. This status changes to 0% in the group with simple cleaning until the end of fattening and 28% in the C&D group. LA-MRSA in environmental and air samples is also reduced over the fattening period. The results indicate that keeping pigs on straw might be one way to reduce LA-MRSA during the fattening period with simple cleaning appearing to be more beneficial than C&D. Further investigations are necessary to determine the influencing factors more precisely.

Value of Probiotics in Canine and Feline Gastroenterology

Probiotics/or synbiotics products for small animals do not fulfill the criteria required to qualify as a probiotic. Studies explaining modes of action are lacking. Outcome measures are inconsistent, with some trials assessing only nonspecific routine diagnostic parameters or fecal scores. Preliminary evidence shows that specific preparations are beneficial in parvovirus infections and acute hemorrhagic diarrhea syndrome in dogs and in Tritrichomonas fetus infection in cats. In dogs, inflammatory bowel disease specific probiotics can decrease clinical severity. More studies focusing on functional outcomes in dogs and cats with well-defined diseases to allow evidence-based clinical use of probiotics and synbiotics are needed.

Antilisterial Potential of Lactic Acid Bacteria in Eliminating Listeria monocytogenes in Host and Ready-to-Eat Food Application

Listeriosis is a severe food borne disease with a mortality rate of up to 30% caused by pathogenic Listeria monocytogenes via the production of several virulence factors including listeriolysin O (LLO), transcriptional activator (PrfA), actin (Act), internalin (Int), etc. It is a foodborne disease predominantly causing infections through consumption of contaminated food and is often associated with ready-to-eat food (RTE) and dairy products. Common medication for listeriosis such as antibiotics might cause an eagle effect and antibiotic resistance if it is overused. Therefore, exploration of the use of lactic acid bacteria (LAB) with probiotic characteristics and multiple antimicrobial properties is increasingly getting attention for their capability to treat listeriosis, vaccine development, and hurdle technologies. The antilisterial gene, a gene coding to produce antimicrobial peptide (AMP), one of the inhibitory substances found in LAB, is one of the potential key factors in listeriosis treatment, coupled with the vast array of functions and strategies; this review summarizes the various strategies by LAB against L. monocytogenes and the prospect in development of a ‘generally regarded as safe’ LAB for treatment of listeriosis.

Cytotoxicity, apoptosis, and IL-8 gene expression induced by some foodborne pathogens in presence of Bacillus coagulans in HT-29 cells

Food poisoning caused by bacteria is one of the most important concerns in food hygiene. The use of probiotics in prevention, control, and treatment of these infections has been considerably increased in recent years. This study evaluated the effect of B. coagulans cell free supernatant (CFS) on growth of Bacillus cereus, Listeria monocytogenes, Staphylococcus aureus, non-pathogenic Escherichia coli, and Escherichia coli 0157:H7 by the broth dilution method. The cytotoxicity, and apoptosis induced by pathogens alone and in co-culture with B. coagulans or its CFS were measured by trypan blue, and fluorescence staining methods. The expression level of interleukin-8 (IL-8) cytokine-encoding genes was also investigated by a qRT-PCR assay in all pathogens and co-cultured groups in HT-29 cells. Our results showed that 4% B. coagulans CFS reduced pathogen growth. The highest rate of growth inhibition was observed in L. monocytogenes. We also found that B. coagulans, and its 4% CFS reduced the cytotoxic effects of pathogens, with the exception of S. aureus. Non-pathogenic E. coli also had no significant cytotoxic effect on the cells. Examination of the treated cells with acridine orange/ethidium bromide staining showed reductions in the rate of cell damage (including early apoptosis, late apoptosis, and necrosis) in pathogen-probiotic co-cultures. Furthermore, we showed that co-culture of pathogens with B. coagulans significantly down-regulated IL-8 gene expression (P < 0.05). The greatest down-regulation compared with pathogen alone was observed in S. aureus. Hence, B. coagulans can be considered as an appropriate probiotic to diminish cytotoxicity, and inflammatory response of enteropathogenic bacteria.

Probiotics mitigating subclinical necrotic enteritis (SNE) as potential alternatives to antibiotics in poultry

Subclinical necrotic enteritis (SNE) caused by Clostridium perfringens (CP), is an important disease in chickens, which causes huge economic losses by damaging the intestinal mucosa, decreasing digestion and absorption of nutrients. Use of antibiotics at a sub-therapeutic level as antimicrobial growth promoters in poultry feed prevents the birds from SNE and improves growth. Due to the ban on the use of antibiotics in 2006 as antimicrobial growth promoters have led to the reemergence of the disease. Worldwide numerous studies have been carried out to investigate the alternatives to antibiotics for the prevention of SNE. Possible alternatives to control SNE include probiotics, prebiotics, bacteriophages, essential oils, organic acids, secondary metabolites and other microbial products. Currently, probiotics are most extensively used in poultry production as an alternative to antibiotics. This review summarizes recent insights and experimental evidence on the use of different microorganisms like Bacillus, Lactic acid bacteria, Bifidobacteria, Enterococcus, yeast, etc. as valuable probiotics for prevention of SNE and potential molecular mechanisms responsible for ameliorating effects of probiotics against SNE.

The effects of probiotic Bacillus coagulans on the cytotoxicity and expression of alpha toxin gene of Clostridium perfringens type A

Around the world, Clostridium perfringens type A is known to be a common foodborne pathogen. Therefore, the control and treatment of food poisoning caused by this pathogen are important. This study investigated, in vitro, the effects of Bacillus coagulans and its culture extracts on alpha toxin gene expression, growth inhibition, cytotoxicity, and apoptosis induced by C. perfringens spore, germinated spore and its enterotoxin. Flow cytometry was used to evaluate the apoptosis rate, and MTT test was used to evaluate cytotoxicity. Minimum inhibitory concentration was also used to measure the percentage of inhibition in the broth medium. Finally, RT-qPCR was used to evaluate alpha toxin gene expression. The results showed that the B. coagulans culture extract was able to inhibit the growth of the germinated spore of C. perfringens. Moreover, treating the extract with pepsin can reduce growth in the broth medium. MTT and flow cytometry showed that both B. coagulans and its extract can significantly reduce the cytotoxicity and apoptosis rate induced by C. perfringens type A. In addition, it was shown that the co-culture of B. coagulans and C. perfringens decreases alpha toxin gene expression. The findings of this study indicate that B. coagulans, with growth inhibition and reduced expression of alpha toxin in C. perfringens, can reduce the cytotoxicity and apoptosis rate induced on HT-29 cells.

Two Lactobacillus Species Inhibit the Growth and α-Toxin Production of Clostridium perfringens and Induced Proinflammatory Factors in Chicken Intestinal Epithelial Cells in Vitro

Clostridium perfringens is the causative pathogen of avian necrotic enteritis. Lactobacillus spp. are well-characterized probiotics with anti-microbial and immune-modulatory activities. In the present study, we investigated the effects of L. acidophilus and L. fermentum on the growth, α-toxin production and inflammatory responses of C. perfringens. In in vitro culture experiments, both lactobacilli inhibited the growth of C. perfringens (P < 0.01), accompanied with a decrease in pH (P < 0.01). Supernatants from lactobacilli cultures also suppressed the growth of C. perfringens during 24 h of incubation (P < 0.01), but this inhibitory effect disappeared after 48 h. Both lactobacilli decreased the α-toxin production of C. perfringens (P < 0.01) without influencing its biomass, and even degraded the established α-toxin (P < 0.01). Lower environmental pH reduced the α-toxin production as well (P < 0.01). Preincubation with L. acidophilus decreased the attachment of C. perfringens to cells (P < 0.01) with the cell cytotoxicity being unaffected. Both lactobacilli pretreatment reduced the up-regulation of proinflammatory factors, peptidoglycan (PGN) receptors and nuclear factor kappa B (NF-κB) p65 in C. perfringens-challenged chicken intestinal epithelial cells (P < 0.05). In conclusion, L. acidophilus and L. fermentum inhibited the pathological effects of C. perfringens in vitro conditions.

Recent Advances and Understanding of Using Probiotic-Based Interventions to Restore Homeostasis of the Microbiome for the Prevention/Therapy of Bacterial Diseases

The importance of the microbiome in health and disease has galvanized interest in using manipulations of the gastrointestinal ecosystem to prevent and/or combat gut bacterial infections and to restore mucosal homeostasis in patients with generalized microbial imbalances (i.e., dysbiosis), including the human inflammatory bowel diseases, Crohn's disease, and ulcerative colitis. Probiotics, prebiotics, or their combination use (i.e., synbiotics) are one mechanism for modifying the microbiota and exerting direct and indirect effects on the host immune responses and metabolomics profiles. These beneficial effects are transferred through various pathways, including the production of antimicrobial peptides, promoting the growth of beneficial microbes and enhancing immunomodulatory functions via various metabolites. While probiotic therapy has been used empirically for decades with mixed success, the recent advances in molecular and mass spectrophotometric techniques for the characterization of the complexity and diversity of the intestinal microbiome has aided in better understanding of host-microbe interactions. It is important to better understand the functional properties of the microbiome, because it is now clear that the microbiota secretes many metabolites that have a direct impact on host immune responses. This information will improve selection of the most appropriate probiotic strains that selectively target intestinal disease processes.

The effects of probiotic Bacillus subtilis on the cytotoxicity of Clostridium perfringens type a in Caco-2 cell culture

Background

Some Bacillus strains have recently been identified for potential use as probiotics and food additives. The present study evaluated the antimicrobial effects of Bacillus subtilis ATCC 6633 and its metabolite on the enterotoxin and vegetative cells, spore and germinated spore of Clostridium perfringens type A in Caco-2 cells.

Results

We used flow cytometry and MTT assays to evaluate the cytotoxicity effect of treatments. According to the results, the most cell survival was found in the 4% crude antimicrobial substance (CAS) with the vegetative form of C. perfringens among co-cultured groups. Furthermore, the apoptosis and necrosis in co-cultured groups were significantly decreased (P < 0.05).

Conclusion

The present results suggested the crucial role of the current probiotic in the control of various forms of C. perfringens type A which was investigated for the first time. Also, the majority of treatments showed higher cell viability in flow cytometry compared to the MTT assay.

Electronic supplementary material

The online version of this article (doi:10.1186/s12866-017-1051-1) contains supplementary material, which is available to authorized users.

Understanding the canine intestinal microbiota and its modification by pro-, pre- and synbiotics - what is the evidence?

Interest in the composition of the intestinal microbiota and possibilities of its therapeutic modifications has soared over the last decade and more detailed knowledge specific to the canine microbiota at different mucosal sites including the gut is available. Probiotics, prebiotics or their combination (synbiotics) are a way of modifying the intestinal microbiota and exert effects on the host immune response. Probiotics are proposed to exert their beneficial effects through various pathways, for example production of antimicrobial peptides, enhancing growth of favourable endogenous microorganisms, competition for epithelial colonisation sites and immune‐modulatory functions. Despite widespread use of pro‐, pre‐ and synbiotics, scientific evidence of their beneficial effects in different conditions of the dog is scarce. Specific effects of different strains, their combination or their potential side‐effects have not been evaluated sufficiently. In some instances, in vitro results have been promising, but could not be transferred consistently into in vivo situations. Specific canine gastrointestinal (GI) diseases or conditions where probiotics would be beneficial, their most appropriate dosage and application have not been assessed extensively. This review summarises the current knowledge of the intestinal microbiome composition in the dog and evaluates the evidence for probiotic use in canine GI diseases to date. It wishes to provide veterinarians with evidence‐based information on when and why these products could be useful in preventing or treating canine GI conditions. It also outlines knowledge about safety and approval of commercial probiotic products, and the potential use of faecal microbial transplantation, as they are related to the topic of probiotic usage.

Alternatives to Antibiotics to Prevent Necrotic Enteritis in Broiler Chickens: A Microbiologist's Perspective

Since the 2006 European ban on the use of antibiotics as growth promoters in animal feed, numerous studies have been published describing alternative strategies to prevent diseases in animals. A particular focus has been on prevention of necrotic enteritis in poultry caused by Clostridium perfringens by the use of microbes or microbe-derived products. Microbes produce a plethora of molecules with antimicrobial properties and they can also have beneficial effects through interactions with their host. Here we review recent developments in novel preventive treatments against C. perfringens-induced necrotic enteritis in broiler chickens that employ yeasts, bacteria and bacteriophages or secondary metabolites and other microbial products in disease control.

Probiotic use in horses - what is the evidence for their clinical efficacy?

The gastrointestinal microbiota is extremely important for human and animal health. Investigations into the composition of the microbiota and its therapeutic modification have received increasing interest in human and veterinary medicine. Probiotics are a way of modifying the microbiota and have been tested to prevent and treat diseases. Probiotics are proposed to exert their beneficial effects through various pathways. Production of antimicrobial compounds targeting intestinal pathogens, general immune stimulation, and colonization resistance are among these mechanisms. Despite widespread availability and use, scientific, peer-reviewed evidence behind commercial probiotic formulations in horses is limited. Additionally, quality control of commercial over-the-counter products is not tightly regulated. Although promising in vitro results have been achieved, in vivo health benefits have been more difficult to prove. Whether the ambiguous results are caused by strain selection, dosage selection or true lack of efficacy remains to be answered. Although these limitations exist, probiotics are increasingly used because of their lack of severe adverse effects, ease of administration, and low cost. This review summarizes the current evidence for probiotic use in equine medicine. It aims to provide veterinarians with evidence-based information on when and why probiotics are indicated for prevention or treatment of gastrointestinal disease in horses. The review also outlines the current state of knowledge on the equine microbiota and the potential of fecal microbial transplantation, as they relate to the topic of probiotics.

Multiple effects of Escherichia coli Nissle 1917 on growth, biofilm formation, and inflammation cytokines profile of Clostridium perfringens type A strain CP4

Clostridium perfringens is an important Gram-positive pathogen responsible for food poisoning, necrotic enteritis, gas gangrene, and even death. Escherichia coli Nissle 1917 (EcN) is a well-characterized probiotic strain with demonstrated benefits. In this study, we evaluated the effects of EcN on growth, toxin production, biofilm formation, and inflammatory cytokine responses of C. perfringens. In vitro co-culture experiments demonstrated that EcN inhibited growth, gas production, and toxin production (α-toxin and NetB) of C. perfringens in a dose-dependent manner. The growth inhibition effect was not observed when C. perfringens was incubated with EcN cell-free supernatants (CFSE), suggesting that growth inhibition was caused by nutrition competition during co-incubation. In vitro studies demonstrated that pre-incubation with EcN did not inhibit C. perfringens attachment to Caco-2 cells, but did reduce C. perfringens total number, toxin production, and cytotoxicity after 24 h. The similar growth inhibition results were also observed during the formation of C. perfringens biofilm. Finally, pre-incubation of EcN with RAW264.7 cells significantly decreased the production of inflammatory cytokines caused by the introduction of C. perfringens. Our results indicate that EcN can inhibit many of the pathological effects of C. perfringens in vitro conditions.

Lactobacillus fermentum, a pathogen in documented cholecystitis

INTRODUCTION

Lactobacillus species are probiotics proven to exhibit various preventative as well as therapeutic properties. While lactobacillus species have been implicated in the formation of dental caries, endocarditis and bacteremia, their role as pathogens in cholecystitis has not been reported. We present a rare case of Lactobacillus fermentum working as a pathogen in cholecystitis.

PRESENTATION OF CASE

An 81-year old male was admitted with right upper quadrant abdominal pain. His signs, symptoms, laboratory values and imaging were consistent with a diagnosis of cholecystitis with ascending cholangitis. In view of his co-morbidity and severe sepsis, the patient was treated non-operatively with antibiotics and cholecystostomy. L. fermentum, which was vancomycin resistant, was identified from the cholecystostomy aspirate and from anaerobic blood culture. The patient went into septic shock, developed multi-organ dysfunction syndrome and eventually died.

DISCUSSION

Commensal bacteria such as L. fermentum are known to modulate immunity, reduce the pathogenicity of gastrointestinal organisms and play a therapeutic role in various disease processes. We isolated L. fermentum as a pathogen in a documented case of cholecystitis with ascending cholangitis.

CONCLUSION

While the routine use lactobacillus species as a probiotic is supported in the literature, understanding its potential role as a pathogen may allow more judicious use of these bacteria and encourage research to elucidate the pathogenicity of lactobacillus species.

Advanced fluorescence technologies help to resolve long-standing questions about microbial vitality

Advances in fundamental physical and optical principles applied to novel fluorescence methods are currently resulting in rapid progress in cell biology and physiology. Instrumentation devised in pioneering laboratories is becoming commercially available, and study findings are now becoming accessible. The first results have concerned mainly higher eukaryotic cells but many more developments can be expected, especially in microbiology. Until now, some important problems of cell physiology have been difficult to investigate due to interactions between probes and cells, excretion of probes from cells and the inability to make in situ observations deep within the cell, within tissues and structures. These technologies will enable microbiologists to address these topics. This Review aims at introducing the limits of current physiology evaluation techniques, the principles of new fluorescence technologies and examples of their use in this field of research for evaluating the physiological state of cells in model media, biofilms or tissue environments. Perspectives on new imaging technologies, such as super-resolution imaging and non-linear highly sensitive Raman microscopy, are also discussed. This review also serves as a reference to those wishing to explore how fluorescence technologies can be used to understand basic cell physiology in microbial systems.