ABSTRACT
Memory and specificity are hallmarks of the adaptive immune system. Contrary to prior belief, innate immune systems can also provide forms of immune memory, such as immune priming in invertebrates and trained immunity in vertebrates. Immune priming can even be specific but differs remarkably in cellular and molecular functionality from the well-studied adaptive immune system of vertebrates. To date, it is unknown whether and how the level of specificity in immune priming can adapt during evolution in response to natural selection. We tested the evolution of priming specificity in an invertebrate model, the beetle Tribolium castaneum Using controlled evolution experiments, we selected beetles for either specific or unspecific immune priming toward the bacteria Pseudomonas fluorescens, Lactococcus lactis, and 4 strains of the entomopathogen Bacillus thuringiensis After 14 generations of host selection, specificity of priming was not universally higher in the lines selected for specificity, but rather depended on the bacterium used for priming and challenge. The insect pathogen B. thuringiensis induced the strongest priming effect. Differences between the evolved populations were mirrored in the transcriptomic response, revealing involvement of immune, metabolic, and transcription-modifying genes. Finally, we demonstrate that the induction strength of a set of differentially expressed immune genes predicts the survival probability of the evolved lines upon infection. We conclude that high specificity of immune priming can evolve rapidly for certain bacteria, most likely due to changes in the regulation of immune genes.
Subject(s)
Bacteria/pathogenicity , Evolution, Molecular , Immunity, Innate/immunology , Larva/immunology , Tribolium/immunology , Animals , Bacillus thuringiensis/pathogenicity , Lactococcus lactis/pathogenicity , Larva/microbiology , Selection, Genetic , Transcriptome , Tribolium/microbiologyABSTRACT
Vaccine administration via the oral route is preferable to parenteral routes due to ease of administration. To date, most available oral vaccines comprises of live attenuated pathogens as oppose to peptide-based vaccines due to its low bioavailability within the gastrointestinal (GI) tract. Over the years, probiotic-based peptide delivery vehicles comprising of lactic acid bacteria such as Lactococcus lactis has emerged as an interesting alternative due to its generally recognized as safe (GRAS) status, a fully sequenced genome, transient gut colonization time, and is an efficient cellular factory for heterologous protein production. However, its survivability through the GI tract is low, thus better delivery approaches are being explored to improve its bioavailability. In this study, we employ the incorporation of a double coated mucoadhesive film consisting of sodium alginate and Lycoat RS 720 film as the inner coat. The formulated film exhibits good mechanical properties of tensile strength and percent elongation for manipulation and handling with an entrapment yield of 93.14±2.74%. The formulated mucoadhesive film is subsequently loaded into gelatin capsules with an outer enteric Eudragit L100-55 coating capable of a pH-dependent breakdown above pH 5.5 to protect against gastric digestion. The final product and unprotected controls were subjected to in vitro simulated gastrointestinal digestions to assess its survivability. The product demonstrated enhanced protection with an increase of 69.22±0.67% (gastric) and 40.61±8.23% (intestinal) survivability compared to unprotected controls after 6 hours of sequential digestion. This translates to a 3.5 fold increase in overall survivability. Owing to this, the proposed oral delivery system has shown promising potential as a live gastrointestinal vaccine delivery host. Further studies involving in vivo gastrointestinal survivability and mice immunization tests are currently being carried out to assess the efficacy of this novel oral delivery system in comparison to parenteral routes.
Subject(s)
Edible Films , Lactococcus lactis/physiology , Acrylic Resins/chemistry , Adhesives/chemistry , Administration, Oral , Alginates/chemistry , Capsules/administration & dosage , Capsules/chemistry , Capsules/pharmacokinetics , Digestion , Gelatin/chemistry , Intestinal Mucosa/microbiology , Lactococcus lactis/pathogenicity , Mouth Mucosa/microbiology , Tensile Strength , Vaccines, Live, Unattenuated/administration & dosageABSTRACT
The main task of the present study was to evaluate an impact of three nisin Z-producing Lactococcus lactis bacteria newly isolated from raw goat milk for some fresh cow cheese characteristics during the storage. Microbiological evaluation for Listeria monocytogenes, Staphylococcus aureus, and viable lactic acid bacteria counts and determination of pH, titratable acidity, and lactic acid concentration of produced cheese were performed after 0, 24, 48, 72, and 96 h. Sensory analysis for the evaluation of acidity, flavor intensity, color intensity, bitterness, and crumbliness of prepared cheese was performed. The changes of volatile compounds in fresh cheese were evaluated using headspace solid phase microextraction (SPME) coupled with gas chromatography-mass spectrometry. Chemometric methods were applied for the data analysis. Study showed that tested bacteria are suitable for the manufacturing of fresh cheese and possible application for fresh cheese biopreservation, as pathogenic bacteria did not grow during 4 days (96 h); chemometric analysis revealed that L. lactis strain LL56 was the most similar to commercially available L. lactis ATCC11454.
Subject(s)
Cheese/microbiology , Lactococcus lactis/metabolism , Nisin/analogs & derivatives , Animals , Cheese/analysis , Hemolysis , Lactococcus lactis/pathogenicity , Milk/microbiology , Nisin/biosynthesis , Virulence FactorsABSTRACT
Streptococcus pyogenes (group A Streptococcus) causes diseases ranging from mild pharyngitis to severe invasive infections. The N-terminal fragment of streptococcal M protein elicits protective antibodies and is an attractive vaccine target. However, this N- terminal fragment is hypervariable: there are more than 200 different M types. In this study, an intranasal live bacterial vaccine comprising 10 strains of Lactococcus lactis, each expressing one N-terminal fragment of M protein, has been developed. Live bacterial-vectored vaccines cost less to manufacture because the processes involved are less complex than those required for production of protein subunit vaccines. Moreover, intranasal administration does not require syringes or specialized personnel. Evaluation of individual vaccine types (M1, M2, M3, M4, M6, M9, M12, M22, M28 and M77) showed that most of them protected mice against challenge with virulent S. pyogenes. All 10 strains combined in a 10-valent vaccine (M×10) induced serum and bronchoalveolar lavage IgG titers that ranged from three- to 10-fold those of unimmunized mice. After intranasal challenge with M28 streptococci, survival of M×10-immunized mice was significantly higher than that of unimmunized mice. In contrast, when mice were challenged with M75 streptococci, survival of M×10-immunized mice did not differ significantly from that of unimmunized mice. Mx-10 immunized mice had significantly less S. pyogenes in oropharyngeal washes and developed less severe disease symptoms after challenge than did unimmunized mice. Our L. lactis-based vaccine may provide an alternative solution to development of broadly protective group A streptococcal vaccines.
Subject(s)
Administration, Intranasal/methods , Antigens, Bacterial/immunology , Bacterial Outer Membrane Proteins/immunology , Carrier Proteins/immunology , Lactococcus lactis/immunology , Streptococcal Infections/prevention & control , Streptococcal Vaccines/immunology , Streptococcus pyogenes/immunology , Vaccination/methods , Vaccines, Attenuated/immunology , Animals , Antibodies, Bacterial/blood , Antigens, Bacterial/classification , Antigens, Bacterial/metabolism , Bacterial Outer Membrane Proteins/classification , Bacterial Outer Membrane Proteins/metabolism , Body Weight , Carrier Proteins/classification , Carrier Proteins/metabolism , Disease Models, Animal , Female , Immunity , Immunization , Immunoglobulin G/blood , Lactococcus lactis/pathogenicity , Mice , Mice, Inbred BALB C , Streptococcal Infections/immunology , Streptococcal Infections/microbiology , Streptococcal Vaccines/administration & dosage , Treatment Outcome , Vaccines, Attenuated/administration & dosage , Vaccines, Synthetic/administration & dosage , Vaccines, Synthetic/immunologyABSTRACT
Lactococcus lactis KTH0-1S isolated from Thai traditional fermented shrimp (Kung-som) is able to produce heat-stable bacteriocin and inhibits food spoilage bacteria and food-borne pathogens. The inhibitory effect of bacteriocin remained intact after treatment with different pHs and after heating, but was sensitive to some proteolytic enzymes. Addition of bacteriocin KTH0-1S to Staphylococcus aureus cultures decreased viable cell counts by 2.8 log CFU/ml, demonstrating a bactericidal mode of action. Furthermore, the growth of S. aureus decreased significantly after 12-h co-cultivation with bacteriocinogenic strain. The molecular mass of bacteriocin KTH0-1S was found to be 3.346 kDa after ammonium sulfate precipitation, reversed phase (C8 Sep-Pak), cation-exchange chromatography, RP-HPLC on C8 column and mass spectrometry (MS/MS) analysis. Bacteriocin KTH0-1S was identified as nisin Z using PCR amplification and sequencing. The majority of tested virulence factors were absent, confirming the safety. Evidenced inhibitory effect of this strain, the absence of virulence factors creates the possibility for its application as protective culture to inhibit pathogenic bacteria in the several fermented seafood products.
Subject(s)
Anti-Bacterial Agents/pharmacology , Bacteriocins/pharmacology , Lactococcus lactis/physiology , Nisin/analogs & derivatives , Staphylococcus aureus/drug effects , Animals , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/isolation & purification , Bacteriocins/chemistry , Bacteriocins/genetics , Bacteriocins/isolation & purification , Fermentation , Lactococcus lactis/drug effects , Lactococcus lactis/isolation & purification , Lactococcus lactis/pathogenicity , Microbial Interactions , Nisin/genetics , Nisin/isolation & purification , Nisin/pharmacology , Penaeidae/microbiology , Shellfish/microbiology , Thailand , Virulence Factors/geneticsABSTRACT
In S. mutans, the expression of the surface glycoprotein Cnm mediates binding to extracellular matrix proteins, endothelial cell invasion and virulence in the Galleria mellonella invertebrate model. To further characterize Cnm as a virulence factor, the cnm gene from S. mutans strain OMZ175 was expressed in the non-pathogenic Lactococcus lactis NZ9800 using a nisin-inducible system. Despite the absence of the machinery necessary for Cnm glycosylation, Western blot and immunofluorescence microscopy analyses demonstrated that Cnm was effectively expressed and translocated to the cell wall of L. lactis. Similar to S. mutans, expression of Cnm in L. lactis enabled robust binding to collagen and laminin, invasion of human coronary artery endothelial cells and increased virulence in G. mellonella. Using an ex vivo human heart tissue colonization model, we showed that Cnm-positive strains of either S. mutans or L. lactis outcompete their Cnm-negative counterparts for tissue colonization. Finally, Cnm expression facilitated L. lactis adhesion and colonization in a rabbit model of infective endocarditis. Collectively, our results provide unequivocal evidence that binding to extracellular matrices mediated by Cnm is an important virulence attribute of S. mutans and confirm the usefulness of the L. lactis heterologous system for further characterization of bacterial virulence factors.
Subject(s)
Adhesins, Bacterial/genetics , Adhesins, Bacterial/metabolism , Bacterial Adhesion , Carrier Proteins/genetics , Carrier Proteins/metabolism , Cytoplasm/microbiology , Endocarditis, Bacterial/microbiology , Lactococcus lactis/genetics , Myocytes, Cardiac/microbiology , Animals , Collagen/metabolism , Coronary Vessels/cytology , Coronary Vessels/microbiology , Disease Models, Animal , Endothelial Cells/microbiology , Humans , Lactococcus lactis/growth & development , Lactococcus lactis/pathogenicity , Lactococcus lactis/physiology , Laminin/metabolism , Larva/microbiology , Moths/microbiology , Nisin/genetics , Rabbits , Streptococcus mutans/genetics , Virulence , Virulence Factors/genetics , Virulence Factors/metabolismABSTRACT
Cytolysin, a two-component lanthipeptide comprising cytolysin S (CylLSâ³) and cytolysin L (CylLLâ³), is the only family member to exhibit lytic activity against mammalian cells in addition to synergistic antimicrobial activity. A subset of the thioether cross-links of CylLSâ³ and CylLLâ³ have ll stereochemistry instead of the canonical dl stereochemistry in all previously characterized lanthipeptides. The synthesis of a CylLSâ³ variant with dl stereochemistry is reported. Its antimicrobial activity was found to be decreased, but not its lytic activity against red blood cells. Hence, the unusual ll stereochemistry is not responsible for the lytic activity.
Subject(s)
Anti-Bacterial Agents/pharmacology , Lactococcus lactis/drug effects , Perforin/pharmacology , Anti-Bacterial Agents/chemical synthesis , Anti-Bacterial Agents/chemistry , Dose-Response Relationship, Drug , Lactococcus lactis/pathogenicity , Microbial Sensitivity Tests , Molecular Conformation , Perforin/chemical synthesis , Perforin/chemistry , Stereoisomerism , Structure-Activity Relationship , Virulence/drug effectsABSTRACT
Inflammatory bowel diseases (IBDs) affect the gastrointestinal tract and are characterized by recurrent inflammation that requires lifelong therapies. Probiotics such as lactic acid bacteria (LAB) have been proposed to complement current treatment protocols for these patients; however, their characteristics are strain dependent. In this regard, certain novel characteristics are only possible through the genetic modification of these beneficial micro-organisms. Different delivery systems, such as protein delivery of anti-oxidant enzymes and anti-inflammatory cytokines, have been shown to be effective in preventing and treating IBD in animal models. In this study, the safety of the recombinant LAB (recLAB) Streptococcus thermophilus CRL807 : CAT, S. thermophilus CRL807 : SOD, Lactococcus lactis NCDO2118 pXILCYT : IL-10, L. lactis MG1363 pValac : IL-10 and L. lactis MG1363 pGroESL : IL-10 with proven beneficial effects was compared to their progenitor strains S. thermophilus CRL807, L. lactis NCDO2118 or L. lactis MG1363. The prolonged administration of these genetically modified strains showed that they were just as safe as the native strains from which they derive, as demonstrated by normal animal growth and relative organ weights, absence of microbial translocation from the gastrointestinal tract, normal blood parameters and intestinal histology. The results show the potential use of these recLAB in future therapeutic formulations; however, the use of modern bio-containment systems is required for the future acceptance of these recLAB by the medical community and patients with IBD.
Subject(s)
Biological Therapy/methods , Colitis/prevention & control , Colitis/therapy , Drug-Related Side Effects and Adverse Reactions , Lactococcus lactis/pathogenicity , Probiotics/adverse effects , Streptococcus thermophilus/pathogenicity , Animal Experimentation , Animals , Female , Lactococcus lactis/genetics , Mice, Inbred BALB C , Streptococcus thermophilus/geneticsABSTRACT
No disponible
Subject(s)
Humans , Female , Adolescent , Lactococcus lactis/pathogenicity , Abscess/microbiology , Thyroiditis, Suppurative/microbiology , Anorexia Nervosa/complicationsABSTRACT
Lactococcus lactis cremoris (L. lactis cremoris) infections are very rare in humans. Only three case reports of brain abscess have been reported and the infectious routes and pathological features are still unknown. We experienced a subdural empyema due to L. lactis cremoris in an immunocompetent adult. A 33-year-old man was admitted with fever, right facial pain, left hemiparesis, and left hemianopsia. Computed tomography demonstrated low density fluid collection in the right falcotentorial subdural space. Magnetic resonance (MR) images revealed a high signal lesion on a diffusion-weighted image (DWI) and fluid attenuated inversion recovery (FLAIR) images in the right paratentorial and parafalcine subdural space, right maxillary sinus, and bilateral ethmoidal sinus. He underwent two sequential open surgeries for removal and drainage of empyema and was treated with antibiotics including meropenem and ampicillin. To our knowledge, this is the first report of subdural empyema caused by L. lactis cremoris infection. We report the case and discuss the pathological features with the previous literature.
Subject(s)
Empyema, Subdural/microbiology , Ethmoid Sinusitis/microbiology , Gram-Positive Bacterial Infections/microbiology , Lactococcus lactis/pathogenicity , Maxillary Sinusitis/microbiology , Adult , Ampicillin/therapeutic use , Combined Modality Therapy , Craniotomy , Decompression, Surgical , Dental Caries/complications , Dental Caries/microbiology , Diagnostic Errors , Diffusion Magnetic Resonance Imaging , Empyema, Subdural/diagnosis , Empyema, Subdural/drug therapy , Empyema, Subdural/surgery , Ethmoid Sinusitis/complications , Ethmoid Sinusitis/diagnosis , Gram-Positive Bacterial Infections/diagnosis , Gram-Positive Bacterial Infections/drug therapy , Gram-Positive Bacterial Infections/surgery , Humans , Immunocompetence , Lactococcus lactis/isolation & purification , Magnetic Resonance Imaging , Male , Maxillary Sinusitis/complications , Maxillary Sinusitis/diagnosis , Meropenem , Thienamycins/therapeutic use , Trigeminal Neuralgia/diagnosisABSTRACT
AIM: Evaluate technologically relevant properties from bacteriocin-producing strains to use as starter/adjunct cultures in cheese making. METHODS AND RESULTS: Eight isolates obtained from Pico cheese produced in Azores (Portugal) were found to produce bacteriocins against Listeria monocytogenes and three isolates against Clostridium perfringens. They were identified as Lactococcus lactis and Enterococcus faecalis and submitted to technological tests: growth at different conditions of temperature and salt, acid production, proteolysis, lipolysis, coexistence, enzymatic profile and autolytic capacity. Safety evaluation was performed by evaluating haemolytic, gelatinase and DNase activity, resistance to antibiotics and the presence of virulence genes. Some isolates presented good technological features such as high autolytic activity, acid and diacetyl production. Lactococcus lactis was negative for all virulence genes tested and inhibit the growth of all Lactic acid bacteria (LAB) isolates. Enterococci were positive for the presence of some virulence genes, but none of the isolates were classified as resistant to important antibiotics. CONCLUSIONS: The bacteriocin-producing Lc. lactis present good potential for application in food as adjunct culture in cheese production. The study also reveals good technological features for some Enterococcus isolates. SIGNIFICANCE AND IMPACT OF THE STUDY: Bacteriocin-producing strains presented important technological properties to be exploited as new adjunct culture for the dairy industry, influencing flavour development and improve safety.
Subject(s)
Anti-Bacterial Agents/biosynthesis , Bacteriocins/biosynthesis , Cheese/microbiology , Enterococcus faecalis/metabolism , Lactococcus lactis/metabolism , Animals , Anti-Bacterial Agents/pharmacology , Bacteriocins/pharmacology , Cattle , Enterococcus faecalis/growth & development , Enterococcus faecalis/isolation & purification , Enterococcus faecalis/pathogenicity , Female , Industrial Microbiology , Lactococcus lactis/growth & development , Lactococcus lactis/isolation & purification , Lactococcus lactis/pathogenicity , PortugalABSTRACT
Lactococcus lactis cremoris is a facultative anaerobic, gram-positive coccus whose natural host is bovine livestock. It may form part of the normal human bacterial flora found in the oropharynx, the gastrointestinal tract and the vagina. This bacterium is essential in the food industry, where it is used in milk fermentation to obtain cheese, yoghurt, etc. Exposure to unpasteurised dairy products has thus been recognised as a risk factor for infection by this organism. It is generally considered to be non-pathogenic, although it appears that pathogenicity may be emerging. We present an atypical case of necrotising pneumonia caused by L. lactis cremoris.
Subject(s)
Dairy Products/microbiology , Food Microbiology , Gram-Positive Bacterial Infections/microbiology , Lactococcus lactis/pathogenicity , Lung/microbiology , Pneumonia, Bacterial/microbiology , Aged , Anti-Bacterial Agents/therapeutic use , Biopsy , Gram-Positive Bacterial Infections/diagnosis , Gram-Positive Bacterial Infections/drug therapy , Humans , Lactococcus lactis/isolation & purification , Lung/diagnostic imaging , Lung/pathology , Male , Microbial Sensitivity Tests , Necrosis , Pneumonia, Bacterial/diagnosis , Pneumonia, Bacterial/drug therapy , Sputum/microbiology , Tomography, X-Ray Computed , Treatment OutcomeABSTRACT
Lactococcus lactis is a non-pathogenic bacterium that is used in the food industry but is also used as a heterologous host to reveal protein functions of pathogenic bacteria. The adhesin PspC from Streptococcus pneumoniae is a choline-binding protein that is non-covalently anchored to the bacterial cell wall. To assess the exclusive impact of pneumococcal surface protein C (PspC) on the interplay with its host we generated recombinant L. lactis producing a nisin-inducible and covalently anchored variant of PspC on the lactococcal cell surface. A translational fusion of the 5'-end of pspC3.4 with the 3'-end of hic (pspC11.4) was designed to decorate the surface of L. lactis with a chimeric PspC. The PspC3.4 part comprises the first 281 aa residues of PspC3.4, while the Hic sequence consists of the proline-rich and sortase-anchored domain. The results demonstrated that PspC is sufficient for adhesion and subsequent invasion of host epithelial cells expressing the human polymeric Ig receptor (hpIgR). Moreover, invasion via hpIgR was even more pronounced when the chimeric PspC was produced by lactococci compared with pneumococci. This study shows also for the first time that PspC plays no significant role during phagocytosis by macrophages. In contrast, recruitment of Factor H via the PspC chimer has a dramatic effect on phagocytosis of recombinant but not wild-type lactococci, as Factor H interacts specifically with the amino-terminal part of PspC and mediates the contact with phagocytes. Furthermore, L. lactis expressing PspC increased intracellular calcium levels in pIgR-expressing epithelial cells, thus resembling the effect of pneumococci, which induced release of Ca(2+) from intracellular stores via the PspC-pIgR mechanism. In conclusion, expression of the chimeric PspC confers adhesive properties to L. lactis and indicates the potential of L. lactis as a suitable host to study the impact of individual bacterial factors on their capacity to interfere with the host and manipulate eukaryotic epithelial cells.
Subject(s)
Bacterial Adhesion , Bacterial Proteins/metabolism , Gene Expression , Lactococcus lactis/pathogenicity , Streptococcus pneumoniae/pathogenicity , Virulence Factors/metabolism , Adhesives , Animals , Bacterial Proteins/genetics , Cell Line , Dogs , Epithelial Cells/microbiology , Humans , Lactococcus lactis/genetics , Membrane Proteins/genetics , Membrane Proteins/metabolism , Receptors, Polymeric Immunoglobulin/metabolism , Recombinant Proteins/genetics , Recombinant Proteins/metabolism , Streptococcus pneumoniae/genetics , Virulence , Virulence Factors/geneticsABSTRACT
Developing effective vaccines is an important weapon in the battle against potential pathogens and their evolving antibiotic resistance trends. Several vaccine delivery vectors have been investigated among which the generally regarded as safe (GRAS) Lactococcus lactis has a distinguished position. In this review, different factors affecting the efficacy of L. lactis-based vaccines are discussed. In addition, the issues of biological containment and pharmaceutical quality assurance of L. lactis vaccines are highlighted. These issues are critical for the success of medical translation of L. lactis-based vaccines from research laboratories to clinical use by ensuring consistent manufacturing of safe and efficacious vaccines.
Subject(s)
Drug Carriers/administration & dosage , Genetic Vectors , Lactococcus lactis/genetics , Lactococcus lactis/immunology , Vaccines/genetics , Vaccines/immunology , Drug Carriers/adverse effects , Humans , Lactococcus lactis/pathogenicity , Technology, Pharmaceutical/methods , Technology, Pharmaceutical/standards , Vaccines/adverse effects , Vaccines/standardsABSTRACT
Lactococcus lactis offers significant potential as a platform for the delivery of vaccines especially via mucosal routes of administration. The organism has an established history of safe use in the food industry and is highly amenable to genetic manipulation, with many systems available for efficient production of secreted and surface-expressed proteins. Here we describe the benefits of using this organism as a vaccine delivery platform and outline how L. lactis based antigen delivery may be improved. Finally we discuss the safe use of L. lactis vectors and outline the potential for use of biological containment systems and killed lactococcal preparations.
Subject(s)
Bacterial Vaccines/genetics , Bacterial Vaccines/immunology , Drug Delivery Systems , Genetic Vectors , Lactococcus lactis/genetics , Adjuvants, Immunologic/administration & dosage , Animals , Bacterial Vaccines/adverse effects , Biomedical Research/trends , Biotechnology/trends , Humans , Lactococcus lactis/pathogenicity , Technology, Pharmaceutical/trends , Vaccination/methods , Vaccines, Synthetic/adverse effects , Vaccines, Synthetic/genetics , Vaccines, Synthetic/immunologyABSTRACT
After enrichment of Odontesthes platensis intestinal contents, 53 lactic acid bacteria (LAB) were isolated. From the four isolates that showed inhibitory activity against Lactococcus garvieae 03/8460, strain TW34 was selected because it exerted the strongest inhibition. It also inhibited other Gram-positive bacteria, but not Gram-negative fish pathogens. Phenotypic and 16S rDNA phylogenetic analyses showed that TW34 belongs to Lactococcus lactis. In addition, TW34 showed to be sensitive to different antibiotics. The production of the inhibitory agent against L. garvieae was growth associated, and it was significantly influenced by the incubation temperature. The optimal temperature for the antimicrobial production was as low as 15 degrees C. Both acidification and hydrogen peroxide production were ruled out as the source of inhibition. In contrast, the antimicrobial activity was completely lost by treatment with proteolytic enzymes, which confirmed that the inhibitory substance was a bacteriocin. The bacteriocin was highly thermostable (121 degrees C for 15 min) and active between pH 3 and 11. It remained stable for up to 2 months when stored at 4 degrees C and up to 6 months at -20 degrees C. Our results suggest that the strain L. lactis TW34 could provide an alternative for lactococcosis control and therefore be considered for future challenge experiments with fish.
Subject(s)
Antibiosis , Fish Diseases/microbiology , Fishes/microbiology , Intestines/microbiology , Lactococcus lactis/isolation & purification , Animals , Bacteriocins/isolation & purification , Culture Media , DNA, Bacterial/genetics , Hydrogen Peroxide/analysis , Lactococcus lactis/genetics , Lactococcus lactis/growth & development , Lactococcus lactis/pathogenicity , Phylogeny , RNA, Ribosomal, 16S/genetics , TemperatureABSTRACT
SpyCEP is a Streptococcus pyogenes protease that cleaves CXCL8/IL-8 and its activity is associated with human invasive disease severity. We investigated the role of SpyCEP in S. pyogenes necrotizing fasciitis and respiratory tract infection in mice using isogenic strains differing only in SpyCEP expression. SpyCEP cleaved human CXCL1, 2, 6 and 8 plus murine CXCL1 and 2 at a structurally conserved site. Mice were infected in thigh muscle with a strain of S. pyogenes that expresses a high level of SpyCEP, or with an isogenic non-SpyCEP expressing strain. SpyCEP expression by S. pyogenes hindered bacterial clearance from muscle, and enhanced bacterial spread, associated with cleavage of murine chemoattractant CXCL1. Mice were then infected with Lactococcus lactis strains that differed only in SpyCEP expression. In contrast to the parent L. lactis strain (lacks SpyCEP), which was avirulent when administered intramuscularly, infection with a strain that expressed SpyCEP heterologously led to dramatic systemic illness within 24 h, failure to clear bacteria from muscle and marked dissemination to other organs. In the upper airways, SpyCEP expression was required for survival of L. lactis but not S. pyogenes. However, dissemination of S. pyogenes to the lung was SpyCEP-dependent and was associated with evidence of chemokine cleavage. Taken together, the studies provide clear evidence that SpyCEP is necessary and sufficient for systemic bacterial dissemination from a soft tissue focus in this model and also underlies dissemination in the respiratory tract.
Subject(s)
Chemokines/metabolism , Fasciitis, Necrotizing/microbiology , Peptide Hydrolases/metabolism , Respiratory Tract Infections/microbiology , Streptococcal Infections/microbiology , Streptococcus pyogenes/enzymology , Virulence Factors/metabolism , Amino Acid Sequence , Animals , Chemokines/antagonists & inhibitors , Colony Count, Microbial , Conserved Sequence , Female , Histocytochemistry , Humans , Lactococcus lactis/genetics , Lactococcus lactis/pathogenicity , Liver/microbiology , Liver/pathology , Lung/microbiology , Lung/pathology , Mice , Microscopy , Molecular Sequence Data , Muscles/microbiology , Muscles/pathology , Peptide Hydrolases/genetics , Sequence Alignment , Spleen/microbiology , Spleen/pathology , Streptococcus pyogenes/genetics , Streptococcus pyogenes/pathogenicity , Virulence Factors/geneticsABSTRACT
Introducción: Lactococcus lactis cremoris es una bacteria perteneciente a la familia Streptococcaceae que normalmente puede aislarse como parte de la microbiota transitoria o residente del tracto gastrointestinal en el ser humano. Se considera esencial en la industria alimenticia donde se emplea en la fermentación de la leche para la obtención de productos derivados como el queso, yogur, mantequilla, entre otros. Objetivos: este caso constituye el primer reporte de un paciente adulto sin evidencias anteriores de inmunodepresión con una meningitis bacteriana por L. lactis. Métodos: se estudió la evolución del caso de una paciente de 73 años de edad, que llegó al cuerpo de guardia del hospital con un cuadro clínico sobreagudo dado por trastornos de la conducta como irritabilidad con inmediata evolución a estado de obnubilación y desorientación. Se realizó el diagnóstico microbiológico utilizando las técnicas convencionales de identificación y los estudios de sensibilidad antimicrobiana. Resultados: se diagnosticó una meningitis bacteriana por L. lactis, bacteria asociada a procesos infecciosos fundamentalmente en pacientes pediátricos e inmunodeprimidos. Conclusiones: el modo de transmisión de la infección es indirecto por vía oral. No se determinó el foco primario de infección a partir del cual se produjo la diseminación dentro del organismo, la cual se considera fue por vía hematógena según la localización anatómica de los sitios donde se encontraron signos de sepsis. En los datos referidos en la historia clínica de la paciente no se encontró ningún antecedente de compromiso de su inmunidad antes del cuadro clínico que motivó el ingreso.
Background: Lactococcus lactis cremoris is a bacteria from Streptococcaceae family that may usually be isolated as part of transient or residing microbiota in the human gastrointestinal tract. It is considered essential element in the food industry where it is used as milk fermenter to obtain byproducts such as cheese, yoghurt, butter and others. Objectives: this is the first report of an adult patient with bacterial meningitis by L. lactis, without a previous history of immunosuppresion. Methods: the evolution of a 73 years-old female patient, who came to the Emergency Department with a very acute clinical picture of behavioural disorders like irritability, immediately evolving into obnulation condition and lack of proper orientation. The conventional identification techniques together with the antimicrobial sensitivity studies allowed making the microbiological diagnosis. Results: bacterial meningitis caused by L. lactis was diagnosed. This bacterium is linked to infectious processes mainly in pediatric and inmmunosuppresed patients. Conclusions: the mode of transmission is indirect and orally. The primary focus of infection from which the virus disseminated inside the body was not found. It was considered then that it occurred according to the anatomical location of the sites where sepsis signs were found. According to the data provided by the patient´s medical history, not a single antecedent of compromised immunity was found before appearing the above-mentioned clinical picture.
Subject(s)
Humans , Female , Aged , Ceftriaxone/therapeutic use , Lactococcus lactis/pathogenicity , Meningitis, Bacterial/complications , Meningitis, Bacterial/diagnosis , Case ReportsABSTRACT
Introducción: Lactococcus lactis cremoris es una bacteria perteneciente a la familia Streptococcaceae que normalmente puede aislarse como parte de la microbiota transitoria o residente del tracto gastrointestinal en el ser humano. Se considera esencial en la industria alimenticia donde se emplea en la fermentación de la leche para la obtención de productos derivados como el queso, yogur, mantequilla, entre otros. Objetivos: este caso constituye el primer reporte de un paciente adulto sin evidencias anteriores de inmunodepresión con una meningitis bacteriana por L. lactis. Métodos: se estudió la evolución del caso de una paciente de 73 años de edad, que llegó al cuerpo de guardia del hospital con un cuadro clínico sobreagudo dado por trastornos de la conducta como irritabilidad con inmediata evolución a estado de obnubilación y desorientación. Se realizó el diagnóstico microbiológico utilizando las técnicas convencionales de identificación y los estudios de sensibilidad antimicrobiana. Resultados: se diagnosticó una meningitis bacteriana por L. lactis, bacteria asociada a procesos infecciosos fundamentalmente en pacientes pediátricos e inmunodeprimidos. Conclusiones: el modo de transmisión de la infección es indirecto por vía oral. No se determinó el foco primario de infección a partir del cual se produjo la diseminación dentro del organismo, la cual se considera fue por vía hematógena según la localización anatómica de los sitios donde se encontraron signos de sepsis. En los datos referidos en la historia clínica de la paciente no se encontró ningún antecedente de compromiso de su inmunidad antes del cuadro clínico que motivó el ingreso(AU)
Background: Lactococcus lactis cremoris is a bacteria from Streptococcaceae family that may usually be isolated as part of transient or residing microbiota in the human gastrointestinal tract. It is considered essential element in the food industry where it is used as milk fermenter to obtain byproducts such as cheese, yoghurt, butter and others. Objectives: this is the first report of an adult patient with bacterial meningitis by L. lactis, without a previous history of immunosuppresion. Methods: the evolution of a 73 years-old female patient, who came to the Emergency Department with a very acute clinical picture of behavioural disorders like irritability, immediately evolving into obnulation condition and lack of proper orientation. The conventional identification techniques together with the antimicrobial sensitivity studies allowed making the microbiological diagnosis. Results: bacterial meningitis caused by L. lactis was diagnosed. This bacterium is linked to infectious processes mainly in pediatric and inmmunosuppresed patients. Conclusions: the mode of transmission is indirect and orally. The primary focus of infection from which the virus disseminated inside the body was not found. It was considered then that it occurred according to the anatomical location of the sites where sepsis signs were found. According to the data provided by the patient´s medical history, not a single antecedent of compromised immunity was found before appearing the above-mentioned clinical picture(AU)
Subject(s)
Humans , Female , Aged , Meningitis, Bacterial/complications , Lactococcus lactis/pathogenicity , Meningitis, Bacterial/diagnosis , Ceftriaxone/therapeutic use , Case ReportsABSTRACT
1. Geographically distinct host populations often experience very different ecological conditions. These variable ecological conditions impact the strength of selection that these hosts experience from their parasites. 2. Numerous studies have characterized geographical patterns of resistance to infection among natural populations in the context of host-parasite local adaptation, but what other factors might contribute to these differences? 3. Here, we determined whether 20 naturally isolated populations of Drosophila melanogaster collected along the East Coast of the United States varied for survival after being inoculated with one of two species of bacteria--Lactococcus lactis and Pseudomonas aeruginosa. We then asked whether host environment accounted for the observed patterns of resistance. 4. Resistance to both types of infection varied spatially. The hosts' natural environment was predictive of the observed spatial variation in resistance to L. lactis, but not P. aeruginosa, infection. Specifically, hosts exposed to species-rich bacterial communities were more likely to survive the infection. 5. We conclude that biotic characteristics of the host environment, specifically the number of species of bacteria hosts encounter, shape host resistance to bacterial infection in nature. We discuss our results in the context of what is known about the evolutionary ecology of resistance in invertebrate systems.