Ana Rodriguez

• PhD
• Senior Researcher at Dairy Institute of Asturias

Bacteriophages (or phages) remain the leading cause of failure in dairy fermentations. Thereby, phage-resistant Lactococcus lactis and Lactococcus cremoris dairy starters are in continuous demand. In this work, our goal was to identify phage defense mechanisms against ceduoviruses encoded by two wild isolates of dairy origin named L. lactis IPLA517...

Bacterial biofilms play an important role in the pathogenesis of infectious diseases but are also very relevant in other fields such as the food industry. This fact has led to an increased focus on the early identification of these structures as prophylaxes to prevent biofilm-related contaminations or infections. One of the objectives of the presen...

Staphylococcus epidermidis is the cause of serious skin and prosthetic joint infections despite being a common inhabitant of human body surfaces. However, both the rise in antibiotic resistance in this species and its ability to form biofilms are increasingly limiting the available therapeutic options against these illnesses. In this landscape, pha...

Environmental cues sometimes have a direct impact on phage particle stability, as well as bacterial physiology and metabolism, having a profound effect on phage infection outcome. Here, we explore the impact of temperature on the interplay between phage Kayvirus rodi (phiIPLA-RODI) and its host, Staphylococcus aureus. Our results show that phiIPLA-...

Introduction Bacteriophages have been shown to penetrate biofilms and replicate if they find suitable host cells. Therefore, these viruses appear to be a good option to tackle the biofilm problem and complement or even substitute more conventional antimicrobials. However, in order to successfully remove biofilms, in particular mature biofilms, phag...

Endolysins, proteins encoded by phages to lyse their hosts and release their progeny, have evolved to adapt to the structural features of each host. The endolysins from Staphylococcus-infecting phages typically feature complex architectures with two enzymatically active domains (EADs) and one cell wall-binding domain (CBD) belonging to the bacteria...

Endolysins, proteins encoded by phages to lyse their hosts and release their progeny, have evolved to adapt to the structural features of each host. The endolysins from Staphylococcus -infecting phages typically feature complex architectures with two enzymatically active domains (EADs) and one cell wall-binding domain (CBD) belonging to the bacteri...

Background Infections by the pathogen Staphylococcus aureus currently represent one of the most serious threats to human health worldwide, especially due to the production of enterotoxins and the ability to form biofilms. These structures and the acquisition of antibiotic resistance limit the action of antibiotics and disinfectants used to combat t...

Therapeutic options to treat bacterial infections caused by Gram-negative pathogens are limited due to the spread of multidrug resistance. Protein engineering of phage-derived lysins can play a key role in the search for new antimicrobial compounds targeting Gram-negative pathogens. A previous high-throughput screen of a combinatorial lysin library...

This article discusses the use of Near Infrared spectroscopy (NIR) combined with multivariate classification methods for detecting bacterial contamination in milk in the dairy industry. In a first experiment, the study found that Nir was accurate and reliable in detecting the presence of biofilms in milk. Our results showed that the technology was...

MicroRNAs (miRNAs) regulate gene expression and might resist adverse physicochemical conditions, which makes them potential biomarkers. They are being investigated as biomarkers of dairy production systems, based on the variations in their levels in raw milk depending on animal diet and management. Whether miRNA levels can serve as biomarkers for d...

Staphylococcus aureus is a Gram-positive human opportunistic pathogen that may also cause food poisoning because of the ability of some strains to produce heat stable enterotoxins that can persist in food even after the pathogen is successfully eliminated. In this context, biopreservation may be a forward-looking strategy to help eliminate staphylo...

In view of the current threat of antibiotic resistance, new antimicrobials with low risk of resistance development are demanded. Lcn972 is a lactococcal bacteriocin that inhibits septum formation by binding to the cell wall precursor lipid II in Lactococcus. It has a species-specific spectrum of activity, making Lcn972 an attractive template to dev...

Bacteriophages are a nuisance in the production of fermented dairy products driven by starter bacteria and strategies to reduce the risk of phage infection are permanently sought. Bearing in mind that the bacterial cell wall plays a pivotal role in host recognition and lysis, our goal was to elucidate to which extent modifications in the cell wall...

Milk contamination with Staphylococcus aureus can lead to food poisoning in consumers. One strategy to minimize this risk is the use of phage-derived lysins, which are innocuous for humans and do not readily select for resistant variants. However, it remains necessary to find new candidate lysins and define the conditions for their utilization. Thi...

Bacteriophages infecting dairy starter bacteria are a leading cause of milk fermentation failure and strategies to reduce the risk of phage infection in dairy settings are demanded. Along with dairy starters, bacteriocin producers (protective cultures) or the direct addition of bacteriocins as biopreservatives may be applied in food to extend shelf...

Despite occurring at the microscopic scale, the armed race between phages and their bacterial hosts involves multiple mechanisms, some of which are just starting to be understood. On the one hand, bacteria have evolved strategies that can stop the viral infection at different stages (adsorption, DNA injection and replication, biosynthesis and assem...

Throughout history, humans have consistently developed strategies to prevent food-associated illnesses. However, despite our multiple technological advances, food safety is still an issue of concern. Moreover, there is a demand for gaining access to less processed and naturally preserved food. Food biopreservation, understood as the use of natural...

Staphylococcus aureus causes various infections in humans and animals, the skin being the principal reservoir of this pathogen. The widespread occurrence of methicillin-resistant S. aureus (MRSA) limits the elimination and treatment of this pathogen. Phage lytic proteins have been proven as efficient antimicrobials against S. aureus . Here, a set o...

Prophages are widely present in Lactococcus lactis , a lactic acid bacterium (LAB) that plays a key role in dairy fermentations. L. lactis MG1363 is a laboratory strain used worldwide as a model LAB. Initially regarded as plasmid- and prophage-free, MG1363 carries two complete prophages TP712 and MG-3. Only TP712 seems to be inducible but unable to...

Pneumonia is an acute pulmonary infection whose high hospitalization and mortality rates can, on occasion, bring healthcare systems to the brink of collapse. Both viral and bacterial pneumonia are uncovering many gaps in our understanding of host–pathogen interactions, and are testing the effectiveness of the currently available antimicrobial strat...

This study reports the draft genome sequences of Staphylococcus aureus V329, a Bap-producing strain isolated from a case of subclinical bovine mastitis in Spain, and a derived mutant (BIM-1) resistant to phage phiIPLA-RODI. Comparison of the two genomes revealed that the mutant strain has a point mutation in the gene tagO .

In the context of the global antibiotic resistance crisis, bacteriophages are increasingly becoming promising antimicrobial agents against multi-resistant bacteria. Indeed, a huge effort is being made to bring phage-derived products to the market, a process that will also require revising the current regulations in order to facilitate their approva...

In just a few months, the current coronavirus pandemic has exposed the need for a more global approach to human health. Indeed, the quick spread of infectious diseases and their unpredictable consequences, in terms of human lives and economic losses, will require a change in our strategy, both at the clinical and the research level. Ultimately, we...

Previous work had shown that, in some Staphylococcus aureus strains, low concentrations of the virulent phage vB_SauM_phiIPLA-RODI (phiIPLA-RODI) promoted the formation of DNA-rich biofilms, whose cells exhibited significant transcriptional differences compared to an uninfected control. This study aimed to dissect the sequence of events leading to...

Resistance against antimicrobial peptides (AMPs) is often mediated by detoxification modules that rely on sensing the AMP through a BceAB-like ATP-binding cassette (ABC) transporter that subsequently activates a cognate two-component system (TCS) to mount the cell response. Here, the Lactococcus lactis ABC transporter YsaDCB is shown to constitute,...

Methicillin-resistant Staphylococcus aureus (MRSA) is a prevalent nosocomial pathogen, causing a wide range of diseases. The increased frequency of MRSA isolates in hospitals and the emergence of vancomycin resistance have sparked the search for new control strategies. This study aimed to characterize sixty-seven MRSA isolates collected from both i...

Lactic acid bacteria (LAB) encompasses industrially relevant bacteria involved in food fermentations as well as health-promoting members of our autochthonous microbiota. In the last years, we have witnessed major progresses in the knowledge of the biology of their cell wall, the outermost macrostructure of a Gram positive cell, which is crucial for...

Healthcare authorities are calling for new antibacterial therapies to cope with the global emergence of antibiotic-resistant bacteria. Bacteriophage-encoded lysins are a novel class of antibacterials with promising (pre)clinical progress. Custom engineering of lysins allows for the creation of variants against potentially any bacterial pathogen. We...

Phage lysins are promising new therapeutics against multidrug-resistant bacteria. These so-called enzybiotics offer, amongst their most notable advantages, high target specificity and low resistance development. Moreover, there are numerous recent and ongoing studies aimed at demonstrating the efficacy and safety of endolysins in animal models or e...

Phage lytic proteins are promising antimicrobials that could complement conventional antibiotics and help to combat multi-drug resistant bacteria that cause important human and animal infections. Here, we report the characterization of endolysin LysRODI (encoded by staphylophage phiIPLA-RODI) and its application as a prophylactic mastitis treatment...

Even though antibiotic resistance in bacteria is a natural phenomenon, the alarming increase in pathogenic bacteria refractory to a wide range of antimicrobials is attracting attention worldwide. Indeed, the World Health Organization (WHO) has recently published a list of priority pathogens for which new antimicrobial alternatives are urgently need...

The lytic cassette of Lactococcus lactis prophage TP712 contains a putative membrane protein of unknown function (Orf54), a holin (Orf55), and a modular endolysin with a N-terminal glycoside hydrolase (GH_25) catalytic domain and two C-terminal LysM domains (Orf56, LysTP712). In this work, we aimed to study the mode of action of the endolysin LysTP...

The increase in antibiotic resistance of pathogenic bacteria has a negative impact on the morbidity and mortality rates associated with nosocomial infections. With the aim of thwarting the spread of resistant strains, multiple studies have assessed the routes of transmission of pathogenic bacteria into and within hospitals, as well as the suitabili...

The alarming spread of multiresistant infections has kick-started the quest for alternative antimicrobials. In a way, given the steady increase in untreatable infectious diseases, success in this endeavor has become a matter of life and death. Perhaps we should stop searching for an antibacterial panacea and explore a multifaceted strategy in which...

Bacterial biofilms constitute a major source of sanitary problems and economic losses in the food industry. Indeed, biofilm removal may require intense mechanical cleaning procedures or very high concentrations of disinfectants or both, which can be damaging to the environment and human health. This study assessed the efficacy of a technique based...

The growing human population is currently facing an unprecedented challenge regarding global food sustainability. Thus, it is of paramount to maintain food production and quality while avoiding a negative impact on climate change and the environment at large. Along the food chain, several practices could compromise future food safety and human heal...

Zymogram or zymography is an electrophoretic technique based on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), which enables visualization of enzymatically active protein species separated by molecular mass. The strategy is to perform SDS-PAGE on the proteins in question while including an opaque substrate of the enzyme embed...

Lactococcus lactis is widely used as a starter in the manufacture of cheese and fermented milk. Its main role is the production of lactic acid, but also contributes to the sensory attributes of cheese. Unfortunately, the diversity of suitable strains to be commercialized as dairy starters is limited. In this work, we have applied adaptive evolution...

Bacteriophages have been proven as effective antimicrobial agents in the treatment of infectious diseases and in other biocontrol applications including food preservation and disinfection. The extensive use of bacteriophages requires improved methodologies for medium- and long-term storage as well as for easy shipping. To this aim, we have determin...

The elimination of bacterial biofilms remains a major challenge due to their recalcitrant nature. Bacteriophages, viruses that infect bacteria, have been gaining increasing attention as biofilm control agents. However, the development of a successful phage-based strategy requires in-depth analysis of different parameters. It is particularly importa...

The antimicrobial properties of bacteriophages make them suitable food biopreservatives. However, such applications require the development of strategies that ensure stability of the phage particles during food processing. In this study, we assess the protective effect of encapsulation of the Staphylococcus aureus bacteriophage phiIPLA-RODI in thre...

Staphylococcus aureus is a major opportunistic pathogen that commonly forms biofilms on various biotic and abiotic surfaces. Also, most isolates are known to carry prophages in their genomes. With this in mind, it seems that acquiring a better knowledge of the impact of prophages on the physiology of S. aureus biofilm cells would be useful for deve...

To move towards a safer and more sustainable food production chain, natural antimicrobials have been traditionally applied to enhance safety. This is well exemplified by the use of bacteriocins, antimicrobial peptides synthesized by bacteria, as food biopreservatives. However, as knowledge on bacteriocin biology develops, novel functions beyond foo...

Background: Lactococcus lactis is the main component of the mesophilic starters used in cheese manufacture. The success of milk fermentation relies on the viability and metabolic activity of the starter bacteria. Therefore, robust strains able to withstand the harsh conditions encountered during cheese manufacture and starter production are demand...

Biofilms are the most common lifestyle of bacteria in both natural and human environments. The organized structure of these multicellular communities generally protects bacterial cells from external challenges, thereby enhancing their ability to survive treatment with antibiotics or disinfectants. For this reason, the search for new antibiofilm str...

The use of bacteriophages for killing pathogenic bacteria is a feasible alternative to antibiotics and disinfectants. To obtain the large quantities of phages required for this application, large-scale production of bacteriophages must be optimized. This study aims to define conditions that maximize the phage yield of the virulent and polyvalent st...

Bacteriophages are currently considered as a promising alternative to antibiotics and disinfectants. However, the use of phages in different clinical and industrial settings will involve their exposure to other disinfectants. As a result, the outcome of the phage treatment will depend on two aspects derived from such interactions. On the one hand,...

Since their discovery, bacteriophages have been traditionally regarded as the natural enemies of bacteria. However, recent advances in molecular biology techniques, especially data from "omics" analyses, have revealed that the interplay between bacterial viruses and their hosts is far more intricate than initially thought. On the one hand, we have...

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most threatening microorganisms for global human health. The current strategies to reduce the impact of S. aureus include a restrictive control of worldwide antibiotic use, prophylactic measures to hinder contamination, and the search for novel antimicrobials to treat human and animal...

The growing concern about multi-drug resistant pathogenic bacteria has led to a renewed interest in the study of bacteriophages as antimicrobials and as therapeutic agents against infectious diseases (phage therapy). Phages to be used for this purpose have to be subjected to in-depth genomic characterization. It is essential to ascribe specific fun...

The history of dairy farming goes back thousands of years, evolving from a traditional small-scale production to the industrialized manufacturing of fermented dairy products. Commercialization of milk and its derived products has been very important not only as a source of nourishment but also as an economic resource. However, the dairy industry ha...

A current focus of research is the development of new tools for removing bacterial biofilms in industrial settings. Bacteriophage-encoded proteins, such as endolysins, virion-associated peptidoglycan hydrolases, and exopolysaccharide depolymerases, have been shown to be efficient against these structures. However, the current screening techniques f...

Phage-derived lytic proteins are a promising alternative to conventional antimicrobials. One of their most interesting properties is that they do not readily select for resistant strains, which is likely due to the fact that their targets are essential for the viability of the bacterial cell. Moreover, genetic engineering allows the design of new “...

Lactic acid bacteria starters are key players in the fast acidification and preservation of raw food materials. However, other non-starter bacterial cultures play a pivotal role in the development of the final characteristics of fermented products. Therefore the functional cultures are those that are able to add a valuable organoleptic, nutritional...

Dairy products are the basis of the human diet and nowadays consumers demand natural, safe and healthy foods, processed without preservatives or chemical synthesis. Biopreservation based on the use of bacteriocins, antimicrobials produced by lactic acid bacteria that have a long history of safe use in dairy fermentation, can guarantee food safety....

An important lesson from the war on pathogenic bacteria has been the need to understand the physiological responses and evolution of natural microbial communities. Bacterial populations in the environment are generally forming biofilms subject to some level of phage predation. These multicellular communities are notoriously resistant to antimicrobi...

Importance: Biofilms represent a major source of contamination in industrial and hospital settings. Therefore, the development of efficient strategies to combat bacterial biofilms is of the utmost importance from a medical as well as an economic perspective. Bacteriophages have shown potential as novel antibiofilm agents, but further research is s...

In this work, the technological behaviour in milk of a set of Lactococcus lactis strains, alone or in combination with strains of Leuconostoc spp. and Lactobacillus spp. isolated from traditional, raw milk cheeses made without commercial starters, was investigated. Small, mixture-specific differences during milk fermentation were recorded for growt...

The efficacy of bacteriophages as antimicrobials has fostered the approval and commercialization of several products intended to reduce the risk of food contamination by pathogenic bacteria. ListShield™ and Listex™ P100 are bacteriophage preparations that aim to combat Listeria monocytogenes in food industries. Here, we assessed the effectiveness o...

Endolysins constitute a promising class of antibacterials against Gram-positive bacteria. Recently, endolysins have been engineered with selected peptides to obtain a new generation of lytic proteins, Artilysins, with specific activity against Gram-negative bacteria. Here, we demonstrate that artilysation can also be used to enhance the antibacteri...

Bacteria found in diverse ecosystems grow in a community of aggregated cells that favors their survival and colonization. Different extracellular polymeric substances are used to entrap this multispecies community forming a biofilm, which can be associated to biotic and abiotic surfaces. This widespread and successful way of bacterial life, however...

Linear regression equations and coefficients of determination (R2) comparing, two by two, the CI, absorbance and counts determined for each biofilm-producer staphylococcal strain. At least five sampling points, along the incubation time, were used for the linear regression calculation. (PDF)

One-way ANOVAs to assess differences between control and treated (endolysin LysH5 or bacteriophage phi-IPLA007) samples during biofilm formation. Differences were considered stable when two or more consecutive p-values were lower than 0.05. (PDF)

Linear regression equations and coefficients of determination (R2) calculated from the absorbance data of Staphylococcus spp. biofilms formed in three abiotic surfaces, compared two by two. Six sampling points, along the incubation time, were used for the linear regression calculation. (PDF)

Statistical analysis of biofilm-related parameters measured at three incubation times. One-way ANOVA tests were performed to establish differences among strains belonging to the same species (*** p<0.001). When needed, mean comparison Duncan tests (p<0.05) were carried out to assign differences among the strains; then, values that do not share a co...

The aim of this work was to examine the biodiversity of bacteriocin-producing lactic acid bacteria from homemade cheeses produced in Veracruz (México) and assess their contribution as adjunct cultures in dairy products. Ninety-three presumptive bacteriocinogenic strains were detected by direct antagonism assays and 29 of them were active against En...

Microbiological contamination in the food industry is often attributed to the presence of biofilms in processing plants. Bacterial biofilms are complex communities of bacteria attached to a surface and surrounded by an extracellular polymeric material. Their extreme resistance to cleaning and disinfecting processes is related to a unique organizati...

Bacteriocins are the subset of antimicrobial peptides (AMPs) produced by bacteria. They are small amphipathic peptides that interact with bacterial membranes leading to cell death. Most of the best known are produced by lactic acid bacteria used as food fermentation starters, because of their potential use as food preservatives. Bacteriocins are di...