Inés Bleriot

Instituto de Investigación Biomédica de A Coruña

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María Tomás

Instituto de Investigación Biomédica de A Coruña

Lucía Blasco

Instituto de Investigación Biomédica de A Coruña

Laura Fernández-García

Universidade da Coruña

María López

Hospital Universitario Infanta Sofía

Olga Pacios

Instituto de Investigación Biomédica de A Coruña

Concha Ortiz-Cartagena

Instituto de Investigación Biomédica de A Coruña

Felipe Fernández-Cuenca

Universidad de Sevilla

Antón Ambroa

Complexo Hospitalario Universitario A Coruña

Germán Bou

Complexo Hospitalario Universitario A Coruña

Jesús Oteo

Centro Nacional de Microbiologia

Cooperative Institutions

Instituto de Salud Carlos III

Centro de Investigación Biomédica en Red

Fundación Seimc-Gesida

Instituto de Investigación Biomédica de A Coruña

Red Espanola de Investigacion en Patologia Infecciosa

Complexo Hospitalario Universitario A Coruña

Universidade da Coruña

Universidad de Sevilla

Instituto de Biomedicina de Sevilla

Hospital Universitario Virgen del Rocío

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RT-LAMP-CRISPR-Cas13a technology as a promising diagnostic tool for the SARS-CoV-2 virus

medRxiv (Cold Spring Harbor Laboratory) (2022)

Concha Ortiz-Cartagena Laura Fernández‐García Lucía Blasco Olga Pacios Inés Bleriot

Abstract At the end of 2019, the new coronavirus, SARS-CoV-2, began a pandemic that persists to date and which has caused more than 6.2 million deaths. In the last couple of years, researchers have made great efforts to develop a diagnostic technique that maintains high levels of sensitivity and specificity, since an accurate and early diagnosis is required to minimize the prevalence of SARS-CoV-2 infection. In this context, CRISPR-Cas systems are proposed as promising tools for development in diagnostic techniques due to their high specificity, highlighting that Cas13 endonuclease discriminates single nucleotide changes and displays a collateral activity against single stranded RNA molecules. With the aim of improve the sensitivity of the diagnosis, this technology is usually combined with isothermal pre-amplification reactions (SHERLOCK, DETECTR). Basing on this, we have developed an RT-LAMP-CRISPR-Cas13a for SARS-CoV-2 virus detection in nasopharyngeal samples without using RNA extraction kit that exhibited 100 % specificity and 83 % sensitivity, as well as a positive predictive value of 100 % and a negative predictive value of 100%, 81%, 79.1% and 66.7 % in <20 Ct, 20-30 Ct, >30 Ct and total Ct values, respectively. Importance During Covid19 crisis has driven the development innovative molecular diagnose including the CRISPR-Cas technology. This work we have performed a protocol working with RNA-extraction kit free samples, places RT-LAMP-CRISPR-Cas13a technology at the top of rapid and specific diagnostic methods for COVID19 due to the high levels of specificity (100%), sensitivity (83%), PPV (100%) and NPV (81% in high loads viral) obtained in clinical samples.

10.1101/2022.06.29.22277060

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Relationship Between Quorum Sensing and Secretion Systems

Frontiers in Microbiology (2019)

Rocío Trastoy Lucía Blasco Antón Ambroa Bertha González‐Pedrajo Laura Fernández-García

Quorum sensing (QS) is a communication mechanism between bacteria that allows specific processes to be controlled, such as biofilm formation, virulence factor expression, production of secondary metabolites and stress adaptation mechanisms such as bacterial competition systems including secretion systems (SS).These SS have an important role in bacterial communication.SS are ubiquitous; they are present in both Gram-negative and Gram-positive bacteria and in Mycobacterium sp.To date, 8 types of SS have been described (T1SS, T2SS, T3SS, T4SS, T5SS, T6SS, T7SS, and T9SS).They have global functions such as the transport of proteases, lipases, adhesins, heme-binding proteins, and amidases, and specific functions such as the synthesis of proteins in host cells, adaptation to the environment, the secretion of effectors to establish an infectious niche, transfer, absorption and release of DNA, translocation of effector proteins or DNA and autotransporter secretion.All of these functions can contribute to virulence and pathogenesis.In this review, we describe the known types of SS and discuss the ones that have been shown to be regulated by QS.Due to the large amount of information about this topic in some pathogens, we focus mainly on Pseudomonas aeruginosa and Vibrio spp.

10.3389/fmicb.2019.01100

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Molecular studies of phages-Klebsiella pneumoniae in mucoid environment: innovative use of mucolytic agents prior to the administration of lytic phages

Frontiers in Microbiology (2023)

Olga Pacios Lucía Blasco Concha Ortiz Cartagena Inés Bleriot Laura Fernández‐García

Mucins are important glycoproteins that form a protective layer throughout the gastrointestinal and respiratory tracts. There is scientific evidence of increase in phage-resistance in the presence of mucin for some bacterial pathogens. Manipulation in mucin composition may ultimately influence the effectiveness of phage therapy. In this work, two clinical strains of K. pneumoniae (K3574 and K3325), were exposed to the lytic bacteriophage vB_KpnS-VAC35 in the presence and absence of mucin on a long-term co-evolution assay, in an attempt to mimic in vitro the exposure to mucins that bacteria and their phages face in vivo. Enumerations of the bacterial and phage counts at regular time intervals were conducted, and extraction of the genomic DNA of co-evolved bacteria to the phage, the mucin and both was performed. We determined the frequency of phage-resistant mutants in the presence and absence of mucin and including a mucolytic agent (N-acetyl L-cysteine, NAC), and sequenced them using Nanopore. We phenotypically demonstrated that the presence of mucin induces the emergence of bacterial resistance against lytic phages, effectively decreased in the presence of NAC. In addition, the genomic analysis revealed some of the genes relevant to the development of phage resistance in long-term co-evolution, with a special focus on the mucoid environment. Genes involved in the metabolism of carbohydrates were mutated in the presence of mucin. In conclusion, the use of mucolytic agents prior to the administration of lytic phages could be an interesting therapeutic option when addressing K. pneumoniae infections in environments where mucin is overproduced.

Lytic cycle

Phage therapy

10.3389/fmicb.2023.1286046

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CRISPR-Cas13a-Based Assay for Accurate Detection of OXA-48 and GES Carbapenemases

Microbiology Spectrum (2023)

Concha Ortiz-Cartagena Daniel Pablo‐Marcos Laura Fernández-García Lucía Blasco Olga Pacios

Carbapenem-resistant pathogens have been recognized as a health concern as they are both difficult to treat and detect in clinical microbiology laboratories. Researchers are making great efforts to develop highly specific, sensitive, accurate, and rapid diagnostic techniques, required to prevent the spread of these microorganisms and improve the prognosis of patients. In this context, CRISPR-Cas systems are proposed as promising tools for the development of diagnostic methods due to their high specificity; the Cas13a endonuclease can discriminate single nucleotide changes and displays collateral cleavage activity against single-stranded RNA molecules when activated. This technology is usually combined with isothermal pre-amplification reactions in order to increase its sensitivity. We have developed a new LAMP-CRISPR-Cas13a-based assay for the detection of OXA-48 and GES carbapenemases in clinical samples without the need for nucleic acid purification and concentration. To evaluate the assay, we used 68 OXA-48-like-producing Klebsiella pneumoniae clinical isolates as well as 64 Enterobacter cloacae complex GES-6, 14 Pseudomonas aeruginosa GES-5, 9 Serratia marcescens GES-6, 5 P. aeruginosa GES-6, and 3 P. aeruginosa (GES-15, GES-27, and GES-40) and 1 K. pneumoniae GES-2 isolates. The assay, which takes less than 2 h and costs approximately 10 € per reaction, exhibited 100% specificity and sensitivity (99% confidence interval [CI]) for both OXA-48 and all GES carbapenemases. IMPORTANCE Carbapenems are one of the last-resort antibiotics for defense against multidrug-resistant pathogens. Multiple nucleic acid amplification methods, including multiplex PCR, multiplex loop-mediated isothermal amplification (LAMP) and multiplex RPAs, can achieve rapid, accurate, and simultaneous detection of several resistance genes to carbapenems in a single reaction. However, these assays need thermal cycling steps and specialized instruments, giving them limited application in the field. In this work, we adapted with high specificity and sensitivity values, a new LAMP CRISPR-Cas13a-based assay for the detection of OXA-48 and GES carbapenemases in clinical samples without the need for RNA extraction.

Gram

10.1128/spectrum.01329-23

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Citations (9)

Genomic analysis of 40 prophages located in the genomes of 16 carbapenemase-producing clinical strains of Klebsiella pneumoniae

Microbial Genomics (2020)

Inés Bleriot Rocío Trastoy Lucía Blasco Felipe Fernández-Cuenca Antón Ambroa

Klebsiella pneumoniae is the clinically most important species within the genus Klebsiella and, as a result of the continuous emergence of multi-drug resistant (MDR) strains, the cause of severe nosocomial infections. The decline in the effectiveness of antibiotic treatments for infections caused by MDR bacteria has generated particular interest in the study of bacteriophages. In this study, we characterized a total of 40 temperate bacteriophages (prophages) with a genome range of 11.454-84.199 kb, predicted from 16 carbapenemase-producing clinical strains of K. pneumoniae belonging to different sequence types, previously identified by multilocus sequence typing. These prophages were grouped into the three families in the order Caudovirales (27 prophages belonging to the family Myoviridae, 10 prophages belonging to the family Siphoviridae and 3 prophages belonging to the family Podoviridae). Genomic comparison of the 40 prophage genomes led to the identification of four prophages isolated from different strains and of genome sizes of around 33.3, 36.1, 39.6 and 42.6 kb. These prophages showed sequence similarities (query cover >90 %, identity >99.9 %) with international Microbe Versus Phage (MVP) (http://mvp.medgenius.info/home) clusters 4762, 4901, 3499 and 4280, respectively. Phylogenetic analysis revealed the evolutionary proximity among the members of the four groups of the most frequently identified prophages in the bacterial genomes studied (33.3, 36.1, 39.6 and 42.6 kb), with bootstrap values of 100 %. This allowed the prophages to be classified into three clusters: A, B and C. Interestingly, these temperate bacteriophages did not infect the highest number of strains as indicated by a host-range assay, these results could be explained by the development of superinfection exclusion mechanisms. In addition, bioinformatic analysis of the 40 identified prophages revealed the presence of 2363 proteins. In total, 59.7 % of the proteins identified had a predicted function, mainly involving viral structure, transcription, replication and regulation (lysogenic/lysis). Interestingly, some proteins had putative functions associated with bacterial virulence (toxin expression and efflux pump regulators), phage defence profiles such as toxin-antitoxin modules, an anti-CRISPR/Cas9 protein, TerB protein (from terZABCDE operon) and methyltransferase proteins.

Prophage

Siphoviridae

Multilocus sequence typing

10.1099/mgen.0.000369

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Citations (33)

The role of PemIK (PemK/PemI) type II TA system from Klebsiella pneumoniae clinical strains in lytic phage infection

Scientific Reports (2022)

Inés Bleriot Lucía Blasco Olga Pacios Laura Fernández-García Antón Ambroa

Abstract Since their discovery, toxin-antitoxin (TA) systems have captivated the attention of many scientists. Recent studies have demonstrated that TA systems play a key role in phage inhibition. The aim of the present study was to investigate the role of the PemIK (PemK/PemI) type II TA system in phage inhibition by its intrinsic expression in clinical strains of Klebsiella pneumoniae carrying the lncL plasmid, which harbours the carbapenemase OXA-48 and the PemK/PemI TA system. Furthermore, induced expression of the system in an IPTG-inducible plasmid in a reference strain of K. pneumoniae ATCC10031 was also studied. The results showed that induced expression of the whole TA system did not inhibit phage infection, whereas overexpression of the pemK toxin prevented early infection. To investigate the molecular mechanism involved in the PemK toxin-mediated inhibition of phage infection, assays measuring metabolic activity and viability were performed, revealing that overexpression of the PemK toxin led to dormancy of the bacteria. Thus, we demonstrate that the PemK/PemI TA system plays a role in phage infection and that the action of the free toxin induces a dormant state in the cells, resulting in inhibition of phage infections.

Lytic cycle

Antitoxin

Lysogenic cycle

10.1038/s41598-022-08111-5

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Citations (27)

Genomic Analysis of Molecular Bacterial Mechanisms of Resistance to Phage Infection

Frontiers in Microbiology (2022)

Antón Ambroa Lucía Blasco María López Olga Pacios Inés Bleriot

To optimize phage therapy, we need to understand how bacteria evolve against phage attacks. One of the main problems of phage therapy is the appearance of bacterial resistance variants. The use of genomics to track antimicrobial resistance is increasingly developed and used in clinical laboratories. For that reason, it is important to consider, in an emerging future with phage therapy, to detect and avoid phage-resistant strains that can be overcome by the analysis of metadata provided by whole-genome sequencing. Here, we identified genes associated with phage resistance in 18 Acinetobacter baumannii clinical strains belonging to the ST-2 clonal complex during a decade (Ab2000 vs. 2010): 9 from 2000 to 9 from 2010. The presence of genes putatively associated with phage resistance was detected. Genes detected were associated with an abortive infection system, restriction–modification system, genes predicted to be associated with defense systems but with unknown function, and CRISPR-Cas system. Between 118 and 171 genes were found in the 18 clinical strains. On average, 26% of these genes were detected inside genomic islands in the 2000 strains and 32% in the 2010 strains. Furthermore, 38 potential CRISPR arrays in 17 of 18 of the strains were found, as well as 705 proteins associated with CRISPR-Cas systems. A moderately higher presence of these genes in the strains of 2010 in comparison with those of 2000 was found, especially those related to the restriction–modification system and CRISPR-Cas system. The presence of these genes in genomic islands at a higher rate in the strains of 2010 compared with those of 2000 was also detected. Whole-genome sequencing and bioinformatics could be powerful tools to avoid drawbacks when a personalized therapy is applied. In this study, it allows us to take care of the phage resistance in A. baumannii clinical strains to prevent a failure in possible phage therapy.

Phage therapy

Acinetobacter baumannii

Comparative Genomics

10.3389/fmicb.2021.784949

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Citations (22)

Prophage identification and molecular analysis in the genomes of Pseudomonas aeruginosa strains isolated from critical care patients

mSphere (2023)

Manuel González de Aledo Lucía Blasco María López Concha Ortiz-Cartagena Inés Bleriot

Prophages are bacteriophages integrated into the bacterial host's chromosome. This research aims to analyze and characterize the existing prophages within a collection of 53 Pseudomonas aeruginosa strains from intensive care units (ICUs) in Portugal and Spain. A total of 113 prophages were localized in the collection, with 18 of them being present in more than one strain simultaneously. After annotation, five of them were discarded as incomplete, and the 13 remaining prophages were characterized. Of 13, 10 belonged to the siphovirus tail morphology group, 2 to the podovirus tail morphology group, and 1 to the myovirus tail morphology group. All prophages had a length ranging from 20,199 to 63,401 bp and a GC% between 56.2% and 63.6%. The number of open reading frames (ORFs) oscillated between 32 and 88, and in 3/13 prophages, more than 50% of the ORFs had an unknown function. With our findings, we show that prophages are present in the majority of the P. aeruginosa strains isolated from Portuguese and Spanish critically ill patients, many of them found in more than one circulating strain at the same time and following a similar clonal distribution pattern. Although a great sum of ORFs had an unknown function, number of proteins in relation to viral defense (anti-CRISPR proteins, toxin/antitoxin modules, proteins against restriction-modification systems) as well as to prophage interference into their host's quorum sensing system and regulatory cascades were found. This supports the idea that prophages have an influence in bacterial pathogenesis and anti-phage defense. IMPORTANCE Despite being known for decades, prophages remain understudied when compared to the lytic phages employed in phage therapy. This research aims to shed some light into the nature, composition, and role of prophages found within a set of circulating strains of Pseudomas aeruginosa, with special attention to high-risk clones. Given the fact that prophages can effectively influence bacterial pathogenesis, prophage basic research constitutes a topic of growing interest. Furthermore, the abundance of viral defense and regulatory proteins within prophage genomes detected in this study evidences the importance of characterizing the most frequent prophages in circulating clinical strains and in high-risk clones if phage therapy is to be used.

Prophage

ORFS

Lysogenic cycle

10.1128/msphere.00128-23

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Citations (3)

Development of an Anti-Acinetobacter baumannii Biofilm Phage Cocktail: Genomic Adaptation to the Host

Antimicrobial Agents and Chemotherapy (2022)

Lucía Blasco Inés Bleriot Manuel González de Aledo Laura Fernández-García Olga Pacios

The need for alternatives to antibiotic therapy due to the emergence of multidrug resistant bacteria (MDR), such as the nosocomial pathogen Acinetobacter baumannii, has led to the recovery of phage therapy. In addition, phages can be combined in cocktails to increase the host range. In this study, the evolutionary mechanism of adaptation was utilized in order to develop a phage adapted to A. baumannii, named phage Ab105-2phiΔCI404ad, from a mutant lytic phage, Ab105-2phiΔCI, previously developed by our group. The whole genome sequence of phage Ab105-2phiΔCI404ad was determined, showing that four genomic rearrangements events occurred in the tail morphogenesis module affecting the ORFs encoding the host receptor binding sites. As a consequence of the genomic rearrangements, 10 ORFs were lost and four new ORFs were obtained, all encoding tail proteins; two inverted regions were also derived from these events. The adaptation process increased the host range of the adapted phage by almost 3-fold. In addition, a depolymerase-expressing phenotype, indicated by formation of a halo, which was not observed in the ancestral phage, was obtained in 81% of the infected strains. A phage cocktail was formed by combining this phage with the A. baumannii phage vB_AbaP_B3, known to express a depolymerase. Both the individual phages and the phage cocktail showed strong antimicrobial activity against 5 clinical strains and 1 reference strain of A. baumannii tested. However, in all cases resistance to the bacterial strains was also observed. The antibiofilm activity of the individual phages and the cocktail was assayed. The phage cocktail displayed strong antibiofilm activity.

Lytic cycle

Acinetobacter baumannii

Phage therapy

ORFS

Myoviridae

Siphoviridae

10.1128/aac.01923-21

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Citations (28)

In vitro and in vivo efficacy of combinations of colistin and different endolysins against clinical strains of multi-drug resistant pathogens

Scientific Reports (2020)

Lucía Blasco Antón Ambroa Rocío Trastoy Inés Bleriot Miriam Moscoso

The emergence of multidrug resistant (MDR) pathogenic bacteria is jeopardizing the value of antimicrobials, which had previously changed the course of medical science. In this study, we identified endolysins ElyA1 and ElyA2 (GH108-PG3 family), present in the genome of bacteriophages Ab1051Φ and Ab1052Φ, respectively. The muralytic activity of these endolysins against MDR clinical isolates (Acinetobacter baumannii, Pseudomonas aeruginosa and Klebsiella pneumoniae) was tested using the turbidity reduction assay. Minimal inhibitory concentrations (MICs) of endolysin, colistin and a combination of endolysin and colistin were determined, and the antimicrobial activity of each treatment was confirmed by time kill curves. Endolysin ElyA1 displayed activity against all 25 strains of A. baumannii and P. aeruginosa tested and against 13 out of 17 strains of K. pneumoniae. Endolysin ElyA2 did not display any such activity. The combined antimicrobial activity of colistin and ElyA1 yielded a reduction in the colistin MIC for all strains studied, except K. pneumoniae. These results were confirmed in vivo in G. mellonella survival assays and in murine skin and lung infection models. In conclusion, combining colistin (1/4 MIC) with the new endolysin ElyA1 (350 µg) enhanced the bactericidal activity of colistin in both in vitro and in vivo studies. This will potentially enable reduction of the dose of colistin used in clinical practice.

Colistin

Acinetobacter baumannii

Lysin

10.1038/s41598-020-64145-7

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Citations (77)