Lactic acid bacteria and human clinical infection

The microbiome in pregnancy and early life-Highlights from the 11th Maria Delivoria-Papadopoulos Perinatal Symposium

This review was based on a symposium that examined novel aspects of the microbiome during pregnancy and early life and explored papers published by the lecturers. For example, it showed that bacterial extracellular vesicles derived from the microbiome harboured in various maternal niches, carried bacterial deoxyribonucleic acid, were isolated from the placenta and may have confounded placental microbiome studies. Maternal diet was responsible for the composition and diversity of breast milk microbiota, and may have shaped the offspring's microbiome and influenced their immune components. Probiotics and antibiotics administered perinatally may have had beneficial but also long-lasting adverse effects on offspring.

Hydrolytic enzyme activity in high-rate anaerobic reactors treating municipal wastewater in temperate climates

Particulate matter hydrolysis is the bottleneck in anaerobic treatment of municipal wastewater in temperate climates. Low temperatures theoretically slow enzyme-substrate interactions, hindering utilization kinetics, but this remains poorly understood. β-glucosidase, protease, and lipase activities were evaluated in two pilot-scale upflow anaerobic sludge blanket (UASB) reactors, inoculated with different sludges and later converted to anaerobic membrane bioreactors (AnMBRs). Despite similar methane production and solids hydrolysis rates, significant differences emerged. Specific activity peaked at 37 °C, excluding the predominance of psychrophilic enzymes. Nevertheless, the Michaelis-Menten constant (Km) indicated high enzyme-substrate affinity at the operational temperature of 15-20 °C, notably greater in AnMBRs. It is shown, for the first time, that different seed sludges can equally adapt, as hydrolytic enzymatic affinity to the substrate reached similar values in the two reactors at the operational temperature and identified that membrane ultrafiltration impacted hydrolysis by a favourable enzyme Michaelis-Menten constant.

Bad to the bone? - Genomic analysis of Enterococcus isolates from diverse environments reveals that most are safe and display potential as food fermentation microorganisms

Enterococci comprise a group of lactic acid bacteria (LAB) with considerable potential to serve as food fermentation microorganisms. Unfortunately, enterococci have received a lot of negative attention, due to the occurrence of pathogenic and multidrug resistant strains. In this study, we used genomics to select safe candidates among the forty-four studied enterococcal isolates. The genomes of the forty-four strains were fully sequenced and assessed for presence of virulence and antibiotic resistance genes. Nineteen isolates belonging to the species Enterococcus lactis, Enterococcus faecium, Enterococcus durans, and Enterococcus thailandicus, were deemed safe from the genome analysis. The presence of secondary metabolite gene clusters for bacteriocins was assessed, and twelve candidates were found to secrete antimicrobial compounds effective against Listeria monocytogenes isolated from cheese and Staphylococcus aureus. Physiological characterization revealed nineteen industrial potentials; all strains grew well at 42 °C and acidified 1.5 hours faster than their mesophilic counterpart Lactococcus lactis, with which they share metabolism and flavor forming ability. We conclude that a large fraction of the examined enterococci were safe and could serve as excellent food fermentation microorganisms with inherent bioprotective abilities.

Necrotising fasciitis with extensive necrosis caused by Lactobacillus: a case report

BACKGROUND

Necrotising fasciitis (NF) is a life-threatening soft-tissue infection that rapidly destroys the epidermis, subcutaneous tissue, and fascia. Despite their low virulence, Lactobacillus spp. can cause NF, and because of its rare incidence, there is limited information about its molecular and clinicopathological characteristics. We report a rare case of NF in a patient with type 2 diabetes mellitus diagnosed on admission and severe obesity due to infection with two types of Lactobacillus spp. that manifested in extensive necrosis.

CASE PRESENTATION

A 48-year-old woman was referred to our hospital with a complaint of difficulty walking due to severe bilateral thigh pain. She presented with mild erythema, swelling, and severe skin pain extending from the pubic region to the groin. The patient was morbidly obese, had renal dysfunction, and had diabetes mellitus diagnosed on admission.; her LRINEC (Laboratory Risk Indicator for Necrotising Fasciitis) score was 9, indicating a high risk of NF. An exploratory surgical incision was made, and NF was diagnosed based on fascial necrosis. Emergent surgical debridement was performed, and cultures of the tissue culture and aspirated fluid/pus revealed two types of Lactobacillus spp.: Lactobacillus salivarius and L. iners. The patient was admitted to the intensive care unit (ICU), where antibiotics were administered and respiratory and circulatory management was performed. Diabetic ketoacidosis was detected, which was treated by controlling the blood glucose level stringently via intravenous insulin infusion. The patient underwent a second debridement on day 11 and a skin suture and skin grafting on day 36. The patient progressed well, was transferred from the ICU to the general ward on day 41, and was discharged unassisted on day 73.

CONCLUSIONS

Lactobacillus spp. are rarely pathogenic to healthy individuals and can scarcely trigger NF. However, these bacteria can cause rare infections such as NF in immunocompromised individuals, such as those with diabetes and obesity, and an early diagnosis of NF is imperative; surgical intervention may be required for the prevention of extensive necrosis. The LRINEC score may be useful for the early diagnosis of NF, even for less pathogenic bacteria such as Lactobacillus.

Pediococcus pentosaceus Endocarditis in a Patient With Recent Transcatheter Aortic Valve Implantation and Liver Cirrhosis: A Case Report and Review of the Literature

Transcatheter aortic valve implantation (TAVI) is increasingly being used in the management of severe aortic stenosis, mainly in older and/or medically compromised patients, due to its minimally invasive nature. As in any valve replacement procedure, endocarditis is a recognized complication, more so in TAVI patients, in whom comorbidities are highly prevalent. We report the case of a 70-year-old male with a history of liver cirrhosis and a recent TAVI, who presented with recurrent fever and sustainedPediococcus pentosaceus bacteremia. The diagnosis of endocarditis was delayed, as the microorganism was initially discarded as a contaminant, given that Pediococci are rarely described as human pathogens. However, in cirrhotic patients, microbiota may cause intermittent bacteremia and thereby affect prosthetic valves. Transthoracic echocardiography was not helpful in validating the diagnosis, as is often the case in TAVI patients. Transesophageal echocardiography was deemed perilous, due to esophageal varices complicating the underlying cirrhosis. Therefore, endocarditis diagnosis was based on sustained bacteremia and Duke's criteria, including the presence of high fever, a predisposing cardiac lesion, splenic infarction, and the exclusion of an alternative diagnosis. Moreover, cirrhosis enhanced the side effects of treatment and led to the need for regimen changes and prolonged hospitalization. Given the precariousness of the situation, confirmation of treatment success by 2-deoxy-2-[fluorine-18]fluoro-D-glucose positron emission tomography-computed tomography (18F-FDG PET-CT) scan was sought. This is the first reported case of Pediococcus TAVI endocarditis in a cirrhotic patient, highlighting the unique challenges in the diagnosis and management of TAVI endocarditis in patients with co-existing conditions.

A Review of Probiotic Ingredient Safety Supporting Monograph Development Conducted by the United States Pharmacopeia (USP)

The United States Pharmacopeia (USP) is an independent, nonprofit science-based organization whose mission is to improve global health through public standards and related products for medicines, food and dietary supplements. Probiotic-based dietary supplements are increasingly popular in the marketplace and USP has developed fourteen monographs specific to probiotic ingredients, including representatives from the Genera Lactobacillus, Bacillus, Streptococcus, and Bifidobacterium. These monographs include the definition of the article, tests for identification, quantification assays (enumeration in the case of probiotics), limits for contaminants, and other quality parameters when appropriate. In addition to quality, the USP also considers the safety of probiotics for monograph development. This report includes an overview of the USP admission evaluation process for probiotics as well as a tabular summary of the probiotic monographs currently available. Pharmacopeia monographs can guide manufacturers and brand owners and protect consumers through establishment of quality standards.

Multilocus genotyping for classification and genetic structuring of Lactobacillus casei: insights from source and geographical origin

The aim of the study in this article is to systematise the newly introduced strains of Lactobacillus based on determining the nucleotide sequence of a particular set of their genes (loci). The primary approach employed to address this issue involves conducting a laboratory experiment. During this experiment, a thorough examination was carried out on a set of organic compounds consisting of small DNA elements from the Lactobacillus genus. The Multilocus genotyping method served as the central technique, complemented by additional molecular-biological and population methods. These additional methods were utilized to determine the extent of phylogenetic similarity among pure cultures of Lactobacillus and to classify them accordingly. The article presents the gene isolates that were used for Multilocus typing; the number of L. casei isolates suitable for Multilocus genotyping was revealed; the gene alleles that allowed classifying L. casei isolates into five sequencing types were revealed; the effectiveness of genetic typing method for Multilocus sequencing was substantiated. The article is of practical value for microbiologists and geneticists in the field of molecular biology, as well as for technologists in the food industry. With the development of applied methods in genetic systematics, it has become possible to study pure culture of Lactobacillus species. The application of modern methods of genotypic classification of Lactobacillus species will make it possible to increase the efficiency of using better and safer products in the food industry and medicine.

Correlation of levels of lactic acid and glucose in cerebrospinal fluid of cerebral hemorrhage patients with the occurrence of postoperative intracranial infection and clinical prognosis

Background

Cerebral haemorrhage is a critical condition that often requires surgical treatment, and postoperative intracranial infection can significantly impact patient outcomes. The aim of the study was to examine the relationship between the levels of lactic acid and glucose in cerebrospinal fluid (CSF) of patients with cerebral haemorrhage and their postoperative intracranial infection and clinical prognosis.

Methods

The study selected the clinical data of 324 patients with cerebral haemorrhage who underwent surgical treatment in our hospital from March 2020 to March 2022 for retrospective analysis and divided these patients into the intracranial infection group (Group A, n=22, leukocyte values in CSF>5×106/L) and the non-intracranial infection group (Group B, n=302, leukocyte values in CSF 5×106/L) according to the occurrence of postoperative intracranial infection in patients to detect the levels of lactic acid and glucose in CSF at different times in the two groups. Pearson method was adopted to analyze the correlation of the levels of lactic acid and glucose in CSF of patients with intracranial infection, and the Glasgow Outcome Scale (GOS) was used to assess the clinical prognosis of patients. According to their scores, these patients were divided into the good prognosis group (GPG, scores of 4-5 points, n=178) and the poor prognosis group (PPG, scores of 1-3 points, n=146). The levels of lactic acid and glucose in the CSF of patients in the two groups were measured, and the Pearson method was adopted to analyze the relationship between these levels and clinical prognosis.

The difference of intestinal microbiota composition between Lantang and Landrace newborn piglets

BACKGROUND

The early development of intestinal microbiota plays a fundamental role in host health and development. To investigate the difference in the intestinal microbial composition between Lantang and Landrace newborn piglets, we amplified and sequenced the V3-V4 region of 16 S rRNA gene in jejunal microbiota of Lantang and landrace newborn.

RESULTS

The findings revealed that the dominant phyla in the jejunum of Lantang piglets were Firmicutes, Actinobacteria and Bacteroidetes, while the dominant phyla of Landrace is Proteobacteria and Fusobacteria. Specifically, Corynebacterium_1, Lactobacillus, Rothia, Granulicatella, Corynebacteriales_unclassified, Corynebacterium, Globicatella and Actinomycetales_unclassified were found to be the dominant genera of Lantang group, while Clostridium_sensu_stricto_1, Escherichia-Shigella, Actinobacillus and Bifidobacterium were the dominant genera of Landrace. Based on the functional prediction of bacteria, we found that bacterial communities from Lantang samples had a significantly greater abundance pathways of fatty acid synthesis, protein synthesis, DNA replication, recombination, repair and material transport across membranes, while the carrier protein of pathogenic bacteria was more abundant in Landrace samples.

CONCLUSIONS

Overall, there was a tremendous difference in the early intestinal flora composition between Landang and Landrace piglets, which was related to the breed characteristics and may be one of the reasons affecting the growth characteristics. However, more further extensive studies should be included to reveal the underlying relationship between early intestinal flora composition in different breeds and pig growth characteristics.

A case of Lactobacillus jensenii associated native valve endocarditis

Lactobacillus jensenii is rarely reported as a cause of endocarditis in immunocompetent patients. We describe a case of Lactobacillus jensenii associated native valve endocarditis that was identified using matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) technology. While most Lactobacillus species are generally resistant to vancomycin, Lactobacillus jensenii is frequently susceptible, but treatment requires accurate susceptibility results followed by timely medical and surgical intervention. Probiotic use in patients can be a risk factor for infection with Lactobacillus species.

Lactobacillus Bacteremia and Probiotics: A Review

Lactobacilli are widely found in nature, are commensal microbes in humans, and are commonly used as probiotics. Concerns about probiotic safety have arisen due to reports of bacteremia and other Lactobacillus-associated infections. We reviewed the literature for articles on the pathogenicity of Lactobacillus spp. bacteremia and reports of probiotics in these patients. Our aim is to review these articles and update the present knowledge on the epidemiology of Lactobacillus spp. bacteremia and determine the role of probiotics in Lactobacillus bacteremia. Lactobacillus bacteremia is infrequent but has a higher risk of mortality and risk factors, including severe underlying diseases, immune system suppression, admission to intensive care units, and use of central venous catheters. A variety of Lactobacillus species may cause bacteremia and may or may not be associated with probiotic exposure. To determine if oral probiotics are the source of these infections, the blood isolates and the oral probiotic strain(s) must be compared by sensitive identification methods. The prevalence of Lactobacillus bacteremia is infrequent but is more common in patients taking probiotics compared to those not taking probiotics. Three probiotics (Lacticaseibacillus rhamnosus GG, Lactiplantibacillus plantarum, and Lacticaseibacillus paracasei) were directly linked with blood isolates from bacteremia patients using molecular identification assays.

Use of Bacteriocins and Bacteriocinogenic Beneficial Organisms in Food Products: Benefits, Challenges, Concerns

This review’s objective was to critically revisit various research approaches for studies on the application of beneficial organisms and bacteriocins as effective biopreservatives in the food industry. There are a substantial number of research papers reporting newly isolated bacterial strains from fermented food products and their application as potential probiotics, including partial characterization of bacteriocins produced by these microorganisms. Most of these studies follow scientific community-accepted standard procedures and propose various applications of the studied strains and bacteriocins as potential biopreservatives for the food industry. A few investigations go somewhat further, performing model studies, exploring the application of expressed bacteriocins in a designed food product, or trying to evaluate the effectiveness of the studied potential probiotics and bacteriocins against foodborne pathogens. Some authors propose applications of bacteriocin producers as starter cultures and are exploring in situ bacteriocin production to aid in the effective control of foodborne pathogens. However, few studies have evaluated the possible adverse effects of bacteriocins, such as toxicity. This comes from well-documented reports on bacteriocins being mostly non-immunogenic and having low cytotoxicity because most of these proteinaceous molecules are small peptides. However, some studies have reported on bacteriocins with noticeable cytotoxicity, which may become even more pronounced in genetically engineered or modified bacteriocins. Moreover, their cytotoxicity can be very specific and is dependent on the concentration of the bacteriocin and the nature of the targeted cell. This will be discussed in detail in the present review.

Lactobacillus rhamnosus Sepsis Associated with Probiotic Therapy in a Term Infant with Congenital Heart Disease

BACKGROUND

Congenital heart diseases (CHD) are the most common birth defects. Necrotizing enterocolitis (NEC) is an important cause of morbidity and mortality in premature infants, and probiotics can be used to protect NEC.

CASE REPORT

We present a term infant with aortic coarctation who developed sepsis with Lactobacillus rhamnosus GG after probiotic use, successfully treated with ampicillin. The baby unfortunately died of acute cardiac arrest on the 90th day of life.

CONCLUSION

Probiotic-associated sepsis may develop in infants with various risk factors such as central catheterization, long-term mechanical ventilation and in those at risk for NEC.

Wheat supplement with buckwheat affect gut microbiome composition and circulate short-chain fatty acids

Buckwheat has beneficial effects on human intestinal health, which is often compounded with wheat to make food. Therefore, the effect of cereals mixture via in vitro fermentation on gut microbes and short-chain fatty acids (SCFAs) were investigated in this study. The mixture of wheat and tartary buckwheat (WT) produced more lactate and acetate, and the mixture of wheat and sweet buckwheat (WE) produced more propionate and butyrate. Compared with wheat (WA), the relative abundance of some beneficial bacteria significantly increased, such as Sutterella in WT and Faecalibacterium in WE. Cereals mixture also affected the expression of functional genes, involved in metabolic pathways and carbohydrate-active enzymes (CAZymes) that modulated SCFAs generation. This study provides new insights into the effects of sweet and tartary buckwheat on intestinal function, which is beneficial to applying both types of buckwheat in practical.

Pulmonary actinomycosis and polymicrobial empyema in a patient with ABPA and bronchocoele

We present a 43-year-old woman, with a history of allergic bronchopulmonary aspergillosis and a chronic bronchocoele, who was admitted to hospital with an infection of the bronchocoele, progressing to a pulmonary abscess and polymicrobial empyema, following dental extraction and regular Lactobacillus probiotic ingestion. Interval chest imaging following this procedure demonstrated worsening right upper lobe opacities and a right-sided pleural effusion. Bronchoscopies identified copious mucoid secretions and an infected bronchocoele with a right upper lobe airways impaction. Oral cavity organisms including Actinomyces odontolyticus were cultured on bronchial washings. Streptococcus mitis and Lactobacillus rhamnosus were cultured in pleural fluid. Treatment with endoscopic mucoid secretion suctioning; intercostal catheter insertion and therapeutic drainage; and antibiotic, glucocorticoid and anti-IgE therapy resulted in clinical and radiological improvement. Our case illustrates the potential pulmonary complications from oral cavity organisms following tooth extraction and probiotic use in patients with chronic lung disease associated with mucoid lesions and airways obstruction.

Lacticaseibacillus rhamnosus: A Suitable Candidate for the Construction of Novel Bioengineered Probiotic Strains for Targeted Pathogen Control

Probiotics, with their associated beneficial effects, have gained popularity for the control of foodborne pathogens. Various sources are explored with the intent to isolate novel robust probiotic strains with a broad range of health benefits due to, among other mechanisms, the production of an array of antimicrobial compounds. One of the shortcomings of these wild-type probiotics is their non-specificity. A pursuit to circumvent this limitation led to the advent of the field of pathobiotechnology. In this discipline, specific pathogen gene(s) are cloned and expressed into a given probiotic to yield a novel pathogen-specific strain. The resultant recombinant probiotic strain will exhibit enhanced species-specific inhibition of the pathogen and its associated infection. Such probiotics are also used as vehicles to deliver therapeutic agents. As fascinating as this approach is, coupled with the availability of numerous probiotics, it brings a challenge with regard to deciding which of the probiotics to use. Nonetheless, it is indisputable that an ideal candidate must fulfil the probiotic selection criteria. This review aims to show how Lacticaseibacillus rhamnosus, a clinically best-studied probiotic, presents as such a candidate. The objective is to spark researchers’ interest to conduct further probiotic-engineering studies using L. rhamnosus, with prospects for the successful development of novel probiotic strains with enhanced beneficial attributes.

Comparative Study of ɛ-Polylysine or Nisin Inhibition Kinetics of Lactococcus lactis and Spoilage Microorganisms in Fresh Flammulina velutipes Fruiting Bodies

Flammulina velutipes is one of the most important edible mushrooms, which quickly decays with a short shelf life. However, little is known about the effect of ɛ-polylysine (ɛ-PL) or nisin on the survival of Lactococcus lactis (L. lactis) during the storage at constant temperatures. The objective of this study was to investigate the effect of ɛ-PL or nisin on the growth of L. lactis and background (BK) microorganisms in fresh Flammulina velutipes fruiting bodies (FVFB) and develop mathematical models to predict their growth behavior. The effect of ɛ-PL (0.15 and 0.30 g/kg) or nisin (0.10 and 0.20 g/kg) on the growth of L. lactis and BK microorganisms in FVFB was analyzed at 4, 16, and 20°C. The lag phase of L. lactis was extended, and the specific growth rate was decreased by increasing concentrations of ɛ-PL or nisin and lowering the temperature. The results showed that ɛ-PL or nisin could control the growth of L. lactis in FVFB. However, the growth of BK microorganisms was not affected by ɛ-PL or nisin. The growth of L. lactis and BK microorganisms could be successfully described by the reparameterized Gompertz and no lag phase models, respectively. Additionally, ɛ-PL or nisin could maintain the quality of FVFB by preventing weight loss, color-changing, and decreasing soluble solid content in FVFB at 4°C. These results suggest that ɛ-PL or nisin in combination with low temperature may inhibit the growth of L. lactis in FVFB and prevent the decrease in the quality of FVFB.

Interplay between Candida albicans and Lactic Acid Bacteria in the Gastrointestinal Tract: Impact on Colonization Resistance, Microbial Carriage, Opportunistic Infection, and Host Immunity

Emerging studies have highlighted the disproportionate role of Candida albicans in influencing both early community assembly of the bacterial microbiome and dysbiosis during allergic diseases and intestinal inflammation. Nonpathogenic colonization of the human gastrointestinal (GI) tract by C. albicans is common, and the role of this single fungal species in modulating bacterial community reassembly after broad-spectrum antibiotics can be readily recapitulated in mouse studies. One of the most notable features of C. albicans-associated dysbiotic states is a marked change in the levels of lactic acid bacteria (LAB). C. albicans and LAB share metabolic niches throughout the GI tract, and in vitro studies have identified various interactions between these microbes. The two predominant LAB affected are Lactobacillus species and Enterococcus species. Lactobacilli can antagonize enterococci and C. albicans, while Enterococcus faecalis and C. albicans have been reported to exhibit a mutualistic relationship. E. faecalis and C. albicans are also causative agents of a variety of life-threatening infections, are frequently isolated together from mixed-species infections, and share certain similarities in clinical presentation-most notably their emergence as opportunistic pathogens following disruption of the microbiota. In this review, we discuss and model the mechanisms used by Lactobacillus species, E. faecalis, and C. albicans to modulate each other's growth and virulence in the GI tract. With multidrug-resistant E. faecalis and C. albicans strains becoming increasingly common in hospital settings, examining the interplay between these three microbes may provide novel insights for enhancing the efficacy of existing antimicrobial therapies.

Recent Advancements in the Technologies Detecting Food Spoiling Agents

To match the current life-style, there is a huge demand and market for the processed food whose manufacturing requires multiple steps. The mounting demand increases the pressure on the producers and the regulatory bodies to provide sensitive, facile, and cost-effective methods to safeguard consumers' health. In the multistep process of food processing, there are several chances that the food-spoiling microbes or contaminants could enter the supply chain. In this contest, there is a dire necessity to comprehend, implement, and monitor the levels of contaminants by utilizing various available methods, such as single-cell droplet microfluidic system, DNA biosensor, nanobiosensor, smartphone-based biosensor, aptasensor, and DNA microarray-based methods. The current review focuses on the advancements in these methods for the detection of food-borne contaminants and pathogens.

The forgotten role of food cultures

Fermentation is one of if not the oldest food processing technique, yet it is still an emerging field when it comes to its numerous mechanisms of action and potential applications. The effect of microbial activity on the taste, bioavailability and preservation of the nutrients and the different food matrices has been deciphered by the insights of molecular microbiology. Among those roles of fermentation in the food chain, biopreservation remains the one most debated. Presumably because it has been underestimated for quite a while, and only considered - based on a food safety and technological approach - from the toxicological and chemical perspective. Biopreservation is not considered as a traditional use, where it has been by design - but forgotten - as the initial goal of fermentation. The 'modern' use of biopreservation is also slightly different from the traditional use, due mainly to changes in cooling of food and other ways of preservation, Extending shelf life is considered to be one of the properties of food additives, classifying - from our perspective - biopreservation wrongly and forgetting the role of fermentation and food cultures. The present review will summarize the current approaches of fermentation as a way to preserve and protect the food, considering the different way in which food cultures and this application could help tackle food waste as an additional control measure to ensure the safety of the food.

Isolation and Molecular Identification of the Native Microflora on Flammulina velutipes Fruiting Bodies and Modeling the Growth of Dominant Microbiota (Lactococcus lactis)

The objectives of this study were to isolate and identify the dominant microorganism in Flammulina velutipes fruiting bodies (FVFB) and to develop kinetic models for describing its growth. The native microflora community on FVFB was isolated and identified using morphological examination and high-throughput sequencing analysis. FVFB presented complex microbial communities with dominant microorganisms being Lactococcus lactis. Irradiated FVFB were inoculated with the isolated strain of L. lactis and cultivated at various temperatures (4, 10, 16, 20, 25, 32, and 37°C). Three primary models, namely the Huang, Baranyi and Roberts, and reparameterized Gompertz models, and three secondary models, namely the Huang square-root, Ratkowsky square-root, and Arrhenius-type models, were developed and evaluated. With the lowest values of mean square error (MSE, 0.023–0.161) and root mean square error (RMSE, 0.152–0.401) values, the reparameterized Gompertz model was more suitable to describe the growth of L. lactis on FVFB than both Huang and Baranyi and Roberts models. The Ratkowsky square-root model provided more accurate estimation for the effect of temperature on the specific growth rate of L. lactis. The minimum growth temperature predicted by the Ratkowsky square-root model was −7.1°C. The kinetic models developed in this study could be used to evaluate the growth behavior of L. lactis on FVFB and estimate the shelf-life of FVFB.

Lactococcus garvieae isolated from Lake Kariba (Zambia) has low invasive potential in Nile tilapia (Oreochromis niloticus)

The pathogenesis of Lactococcus garvieae (L. garvieae) was assessed in Nile tilapia (Oreochromis niloticus) following administration by two different routes of infection (intraperitoneal versus immersion), using 180 fish divided into three groups. The first group of fish was injected intraperitoneally (IP) with 3 × 10⁵ colony-forming units (cfu) of L. garvieae; the second group was infected by immersion (IMM) into water containing 9.6 × 10⁵  cfu/ml L. garvieae, and in group 3 (Control), the fish were injected IP with sterile normal saline. Mortalities were recorded daily, and on 3, 5, 7, and 13 days post-infection (dpi), liver, kidney, spleen, brain and eyes were sampled. The level of infection between groups was assessed by number of mortalities that occurred, pathology/histopathology of internal organs, bacterial re-isolation and presence of bacteria in situ determined using immunohistochemistry. A significant difference (p < .0001) was observed between L. garvieae re-isolation from tilapia following administration by IP injection and IMM. Similarly, more clinical signs and mortalities (p < .001) were observed in the IP group compared to the IMM group where no mortalities were observed. These findings suggest that L. garvieae has a low invasive potential in Nile tilapia with intact skin/external barriers and highlights the importance of maintaining fish without cuts or abrasions under field conditions.

Hydrogen sulfide toxicity in the gut environment: Meta-analysis of sulfate-reducing and lactic acid bacteria in inflammatory processes

BACKGROUND

Hydrogen sulfide is the final product of sulfate-reducing bacteria metabolism. Its high concentration in the gut can affect adversely bowel environment and intestinal microbiota by toxicity and pH lowering.

AIM OF REVIEW

The aim of the review was to give observations related to the properties of bacterial communities inhabiting the gut, with the emphasis on sulfate-reducing bacteria and lactic acid bacteria.

KEY SCIENTIFIC CONCEPTS OF REVIEW

The conduction of meta-analysis was another goal, since it gave statistical observation of the relevant studies. The review literature consisted of more than 160 studies, published from 1945 to 2019. Meta-analysis included 16 studies and they were chosen from the Web of Science database. The systematic review gave important information about the development of gut inflammation, with emphasis on sulfate-reducing and lactic acid bacteria. Oppositely from sulfate-reducing bacteria, probiotic properties of lactic acid bacteria are effective inhibitors against inflammatory bowel disease development, including ulcerative colitis. These facts were confirmed by the conducted meta-analysis. The results and observations gained from the systematic review represent the emphasized importance of gut microbiota for bowel inflammation. On the other side, it should be stated that more studies in the future will provide even better confirmations.

Fatal Lactobacillus endocarditis in a patient with transcatheter aortic valve replacement

Lactobacillus species may translocate from the gastrointestinal tract into systemic circulation from ingested probiotics or commensal flora. Their pathogenic potential is still debated. Lactobacillus endocarditis is a rare entity with only around 120 cases reported in the literature. Here, we report the first case of fatal Lactobacillus endocarditis with involvement of a transcatheter aortic valve replacement with the following goals: to reaffirm the pathological significance of Lactobacillus spp, to demonstrate the potential limitations of the modified Duke criteria in diagnosing infective endocarditis of transcatheter aortic valve replacement, and to urge clinicians to aggressively search for and consider empiric treatment for endocarditis in patients with prosthetic valves who develop Lactobacillus bacteraemia.

Microbial Fermentation and Its Role in Quality Improvement of Fermented Foods

Fermentation processes in foods often lead to changes in nutritional and biochemical quality relative to the starting ingredients. Fermented foods comprise very complex ecosystems consisting of enzymes from raw ingredients that interact with the fermenting microorganisms’ metabolic activities. Fermenting microorganisms provide a unique approach towards food stability via physical and biochemical changes in fermented foods. These fermented foods can benefit consumers compared to simple foods in terms of antioxidants, production of peptides, organoleptic and probiotic properties, and antimicrobial activity. It also helps in the levels of anti-nutrients and toxins level. The quality and quantity of microbial communities in fermented foods vary based on the manufacturing process and storage conditions/durability. This review contributes to current research on biochemical changes during the fermentation of foods. The focus will be on the changes in the biochemical compounds that determine the characteristics of final fermented food products from original food resources.

Microbiota Imbalance Contributes to COPD Deterioration by Enhancing IL-17a Production via miR-122 and miR-30a

The changes of microbiota in lungs could change interleukin-17a (IL-17a) expression by altering microRNAs (miRNAs) profile, thus contributing to the pathogenesis of chronic obstructive pulmonary disease (COPD). In this study, we aimed to study molecular mechanisms’ underlying effect of microbiota imbalance on COPD deterioration. Real-time polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA) were performed to analyze expression of miRNAs and IL-17a mRNA. ELISA was used to evaluate abundance of IL-17a in plasma, peripheral blood monocyte, and sputum of COPD mice and patients. Luciferase assay was performed to explore underlying molecular mechanisms. The expression of miR-122, miR-30a, and miR-99b were remarkably decreased in COPD mice, while the expression of IL-17a was notably increased in plasma, peripheral blood monocytes, and lung tissues of COPD mice. The levels of Lactobacillus/Moraxella and IL-17a expression were significantly enhanced in sputum of exacerbated COPD patients, along with notably decreased expression of miR-122 and miR-30a. Luciferase assay confirmed that miR-122 and miR-30a played an inhibitory role in IL-17a expression. We identified miR-122 and miR-30a as differentially expressed miRNAs in sputum and plasma of COPD patients in exacerbation-month12 group. Furthermore, downregulated miR-122 and miR-30a expression associated with microbiota imbalance may contribute to COPD deterioration by enhancing IL-17a production.

Linking bacterial community shifts with changes in the dissolved organic matter pool in a eutrophic lake

Aquatic bacterial communities play crucial roles in the circulation of nutrients in watershed ecosystems. However, the interaction between bacterial communities and chromophoric dissolved organic matter (CDOM) in freshwater ecosystems has not been studied in depth. In our study, we examined the constitution and interactions of CDOM with the bacterial community in Lake Chaohu and its inflow rivers under the influence of different exogenous pollutants. The results revealed that the bacterial community diversity in the inflow rivers was significantly lower than that in the lake sites. Clustering of different types of polluted inflow rivers integrated with the most abundant genera observed in specific areas indicated that environmentally guided species selection had a large impact on the composition of aquatic bacterial communities. Moreover, our study suggests that communities in lake environments may be more susceptible to interference through a variety of physiologies or via functional redundancy, allowing them to preserve their community structure. Through linear discriminant analysis effect size (Lefse) methods, we revealed that some taxa (from phylum to genus) were consistently enriched in the lake sites. Based on correlation network analysis results, the supersession niches of bacterial community members related to different CDOM in the biogeochemical process was determined. This study provides an ecological basis for the control of external pollution and the protection of the water environment in watershed ecosystems.

Hydrogen Sulfide Effects on the Survival of Lactobacilli with Emphasis on the Development of Inflammatory Bowel Diseases

The gut microbiota is a complex component of humans that depends on diet, host genome, and lifestyle. The background: The study purpose is to find relations between nutrition, intestinal lactic acid bacteria (LAB) from various environments (human, animal intestine, and yogurt) and sulfate-reducing microbial communities in the large intestine; to compare kinetic growth parameters of LAB; and to determine their sensitivity to different concentration of hydrogen sulfide produced by intestinal sulfate-reducing bacteria.

METHODS

Microbiological (isolation and identification), biochemical (electrophoresis), molecular biology methods (DNA isolation and PCR analysis), and statistical processing (average and standard error calculations) of the results were used.

THE RESULTS

The toxicity of hydrogen sulfide produced by sulfate-reducing bacteria, the survival of lactic acid bacteria, and minimal inhibitory concentrations (MIC) were determined. The measured hydrogen sulfide sensitivity values were the same for L. paracasei and L. reuteri (MIC > 1.1 mM). In addition, L. plantarum and L.fermentum showed also a similar sensitivity (MIC > 0.45 mM) but significantly (p < 0.05) lower than L.reuteri and L. paracasei (1.1 > 0.45 mM). L. paracasei and L. reuteri are more sensitive to hydrogen sulfide than L. fermentum and L. plantarum. L. pentosus was sensitive to the extremely low concentration of H2S (MIC > 0.15 mM).

CONCLUSIONS

The Lactobacillus species were significantly sensitive to hydrogen sulfide, which is a final metabolite of intestinal sulfate-reducing bacteria. The results are definitely helpful for a better understanding of complicated interaction among intestinal microbiota and nutrition.

L. pseudomesenteroides and L. johnsonii isolated from yaks in Tibet modulate gut microbiota in mice to ameliorate enteroinvasive Escherichia coli-induced diarrhea

Enteroinvasive Escherichia coli (EIEC) are well-known food-borne pathogens that cause animal intestinal diseases. Lactobacillus is believed to inhibit intestinal pathogens and maintain a healthy gut microbiota. This study aimed to investigate the effects of pre-supplementation of Lactobacillus from yaks (4500m) to prevent the clinical symptoms and the improvement of the disordered flora caused by E. coli infection. Forty healthy mice were randomized to four study groups (n = 10); Leuconostoc pseudomesenteroides (LP1), Lactobacillus johnsonii (LJ1), blank control, and control groups. Mice in the LP1, LJ1, and control groups were intraperitoneally challenged with EIEC O124 (1 × 109 CFU) on day 23. After two days, the mice in control group were recorded for high mortality. The diarrhea in LP1 and LJ1 groups was much lower than that in the control group, and no death was recorded. In histopathology, pre-supplementation of LJ1 and LP1 relieved the damage to the liver, spleen and duodenum caused by E. coli. In addition, the normal intestinal microecology was also affected by infection of EIEC, including an increase in relative abundance of Proteobacteria. At the same time, the beneficial bacteria were increased and harmful bacteria were decreased in different intestinal segments of the LJ1 and LP1 groups compared to the control group. In conclusion, pre-supplementation of LP1 and LJ1 can mitigate EIEC-induced intestinal flora dysbiosis and can also reduce EIEC-associated diarrhea.

Examination of the temporal and spatial dynamics of the gut microbiome in newborn piglets reveals distinct microbial communities in six intestinal segments

Intestinal microbiota plays a crucial role in immune development and disease progression in mammals from birth onwards. The gastrointestinal tract of newborn mammals is rapidly colonized by microbes with tremendous biomass and diversity. Understanding how this complex of segmental communities evolves in different gastrointestinal sites over time has great biological significance and medical implications. However, most previous reports examining intestinal microbiota have focused on fecal samples, a strategy that overlooks the spatial microbial dynamics in different intestinal segments. Using intestinal digesta from six intestinal segments (duodenum, jejunum, ileum, cecum, colon and rectum) of newborn piglets, we herein conducted a large-scale 16S rRNA gene sequencing-based study to characterize the segmental dynamics of porcine gut microbiota at eight postnatal intervals (days 1, 7, 14, 21, 28, 35, 120 and 180). A total of 4,465 OTUs were obtained and showed that the six intestinal segments could be divided into three parts; in the duodenum-jejunum section, the most abundant genera included Lactobacillus and Bacteroides; in the ileum, Fusobacterium and Escherichia; and in the cecum-rectum section, Prevotella. Although the microbial communities of the piglets were similar among the six intestinal segments on postnatal day 1, they evolved and quickly differentiated at later intervals. An examination of time-dependent alterations in the dominant microbes revealed that the microbiome in the large intestine was very different from and much more stable than that in the small intestine. The gut microbiota in newborn piglets exhibited apparent temporal and spatial variations in different intestinal segments. The database of gut microbes in piglets could be a referable resource for future studies on mammalian gut microbiome development in early host growth phases.

Enterococcus faecalis EF-2001 protects DNBS-induced inflammatory bowel disease in mice model

Recent studies have demonstrated the immunomodulatory effects of heat-killed lactic acid bacteria. The aim of this study was to evaluate the protective effect of heat-killed Enterococcus faecalis EF-2001 (EF-2001) on a model of inflammatory bowel disease (IBD). A total of 28 female NC/Nga mice were divided into 4 treatment groups. Controls were fed a normal commercial diet. In the experimental groups, colitis was induced by rectal administration of dinitrobenzene sulfonic acid. Two groups were orally administered 2 and 17 mg/kg EF-2001, respectively. EF-2001 treatment decreased the expression of several cytokines, including cyclooxygenase (COX)-2, inducible nitric oxide synthase (iNOS), interferon (IFN)-γ, interleukin (IL)-1β, and IL-6 in inflamed colon compared to the DNBS alone group. In addition, EF-2001 suppressed DNBS-induced colonic tissue destruction. Therefore, this study strongly suggests that EF-2001 could alleviate the inflammation associated with mouse IBD.

Presence of extracellular DNA & protein in biofilm formation by gentamicin-resistant Lactobacillus plantarum

Background & objectives

Bacterial biofilms a multi-layered defence, comprise extracellular DNA (eDNA) and proteins, protect bacteria from harmful environment and nutrient limitation and utilize the mutual benefits within a community. Bacterial biofilms also defend bacteria from harsh environments such as antibiotic treatment. This leads to poor antibiotic penetration, slow growth, adaptive stress responses, and formation of persister cells. This study was done to determine the relation of antibiotic resistance deciphered by the biofilms in Lactobacillus plantarum, a lactic acid bacteria (LAB) with probiotic significance.

Methods

The gentamicin-resistant L. plantarum isolates were allowed to form biofilms and subjected to DNase I and proteinase K treatment. The optical density (OD) values were recorded for the biofilm assay and the cell count for the number of viable cells was taken for the control and the test samples. Percentage reduction was calculated based on the difference between the initial and final OD for both the parameters.

Results

The biofilm assay revealed that the native L. plantarum isolates which were phenotypically susceptible, possessed the ability to form biofilms. The OD values were significantly decreased in comparison to the biofilm-forming control culture when these were treated with DNase I and proteinase K.

Interpretation & conclusions

The study revealed that the biofilms formed by L. plantarum comprised of eDNA and proteins which was evidenced by the reduction in OD values and percentage in comparison to the control upon DNase I and proteinase K treatment. This indicates that the eDNA and biofilm matrix proteins are vital constituents of biofilms and may carry significant risk when coupled with antibiotic resistance.

Infective endocarditis caused by Lactococcus lactis subsp. lactis and Pediococcus pentosaceus: A case report and literature review

RATIONALE

Lactococcus lactis and Pediococcus pentosaceus are rare pathogens which rarely caused infections in humans. Several cases with L. lactis endocarditis have been reported in the literature, among them few were caused by L. lactis subsp. Lactis. Opportunistic P. pentosaceus infections were rarely reported.

PATIENT CONCERNS

A 66-year-old man presented to our hospital due to persistent fever for 15 days. A physical checking revealed a grade II holosystolic murmur at the heart apex. A chest computed tomography (CT) scan suggested bronchitis. L. lactis subsp. lactis was identified in blood cultures. Transthoracic and transesophageal echocardiography revealed the presence of a large hyperechogenic mass in the left atrium, and a large floating vegetation on the mitral valve with a severe mitral regurgitation.

DIAGNOSIS

Infectious endocarditis caused by L. lactis subsp. Lactis was diagnosed.

INTERVENTIONS

Levofloxacin (0.5 g/day) was used for 20 days; however, L. lactis subsp. lactis remained to be isolated from blood culture. Therefore, vancomycin (2 g/day) was used to replace levofloxacin. Six days after the treatment with vancomycin, the blood culture revealed no L. lactis subspecies lactis, but yielded a growth of gram-positive and non-spore forming cocci; and P. pentosaceus was identified. Antimicrobial susceptibility test revealed P. pentosaceus was sensitive to penicillin and levofloxacin. Vancomycin was discontinued, and levofloxacin (0.5 g/day) was restarted and treated for another 7 days. The patient recovered with negative blood culture results, and discharged from the hospital.

OUTCOMES

The patient recovered with negative blood culture results, and discharged from the hospital.

LESSONS

Our patient had a long-period of antibiotic treatment with strategy alterations. Standard interpretation criteria of Clinical and Laboratory Standards Institute (CLSI) for L. lactis should be established, and molecular tests will increase the identification rate of L. lactis infections.

Genotypic and phenotypic diversity of Lactobacillus rhamnosus clinical isolates, their comparison with strain GG and their recognition by complement system

Lactobacillus rhamnosus strains are ubiquitous in fermented foods, and in the human body where they are commensals naturally present in the normal microbiota composition of gut, vagina and skin. However, in some cases, Lactobacillus spp. have been implicated in bacteremia. The aim of the study was to examine the genomic and immunological properties of 16 clinical blood isolates of L. rhamnosus and to compare them to the well-studied L. rhamnosus probiotic strain GG. Blood cultures from bacteremic patients were collected at the Helsinki University Hospital laboratory in 2005–2011 and L. rhamnosus strains were isolated and characterized by genomic sequencing. The capacity of the L. rhamnosus strains to activate serum complement was studied using immunological assays for complement factor C3a and the terminal pathway complement complex (TCC). Binding of complement regulators factor H and C4bp was also determined using radioligand assays. Furthermore, the isolated strains were evaluated for their ability to aggregate platelets and to form biofilms in vitro. Genomic comparison between the clinical L. rhamnosus strains showed them to be clearly different from L. rhamnosus GG and to cluster in two distinct lineages. All L. rhamnosus strains activated complement in serum and none of them bound complement regulators. Four out of 16 clinical blood isolates induced platelet aggregation and/or formed more biofilms than L. rhamnosus GG, which did not display platelet aggregation activity nor showed strong biofilm formation. These findings suggest that clinical L. rhamnosus isolates show considerable heterogeneity but are clearly different from L. rhamnosus GG at the genomic level. All L. rhamnosus strains are still normally recognized by the human complement system.

Lactobacillus rhamnosus Endocarditis After Upper Endoscopy

Lactobacillus rhamnosus is commonly found in gastrointestinal flora and used in probiotics but is a rare human pathogen. We report a case of L. rhamnosus endocarditis following upper endoscopy in a frequent consumer of yogurt containing the organism, who required aortic and mitral valve replacement for cure.

Heat-Killed Enterococcus faecalis EF-2001 Ameliorates Atopic Dermatitis in a Murine Model

Recent reports have shown the immunomodulatory effect of heat-killed lactic acid bacteria. Atopic dermatitis (AD) is an allergic skin disease, caused by immune dysregulation among other factors. The aim of this study was to assess the effect of heat-killed Enterococcus faecalis EF-2001 (EF-2001) on AD. We established an in vivo AD model by repeated local exposure of Dermatophagoides farinae extract (DFE; house dust mite extract) and 2,4-dinitrochlorobenzene (DNCB) to the ears of mice. After oral administration of EF-2001 for four weeks, the epidermal and dermal ear thickness, mast cell infiltration, and serum immunoglobulin levels were measured. In addition, the gene expression levels of pathogenic cytokines in the ears, lymph nodes, and splenocytes were assayed. EF-2001 attenuated AD symptoms based on the ear thickness, histopathological analysis, and serum immunoglobulin levels. Moreover, EF-2001 decreased the DFE/DNCB-induced expression of various pathogenic cytokines in the ears, lymph nodes, and splenocytes. These results suggest that EF-2001 has therapeutic potential in the treatment of AD owing to its immunomodulatory effects.

Lactobacillus species: taxonomic complexity and controversial susceptibilities

The genus Lactobacillus is a taxonomically complex and is composed of over 170 species that cannot be easily differentiated phenotypically and often require molecular identification. Although they are part of the normal human gastrointestinal and vaginal flora, they can also be occasional human pathogens. They are extensively used in a variety of commercial products including probiotics. Their antimicrobial susceptibilities are poorly defined in part because of their taxonomic complexity and are compounded by the different methods recommended by Clinical Laboratory Standards Institute and International Dairy Foundation. Their use as probiotics for prevention of Clostridium difficile infection is prevalent among consumers worldwide but raises the question of will the use of any concurrent antibiotic effect their ability to survive. Lactobacillus species are generally acid resistant and are able to survive ingestion. They are generally resistant to metronidazole, aminoglycosides and ciprofloxacin with L. acidophilus being susceptible to penicillin and vancomycin, whereas L. rhamnosus and L. casei are resistant to metronidazole and vancomycin.

Procedure of brewing alcohol as a staple food: case study of the fermented cereal liquor "Parshot" as a staple food in Dirashe special woreda, southern Ethiopia

For most brews, alcohol fermentation and lactic fermentation take place simultaneously during the brewing process, and alcohol fermentation can progress smoothly because the propagation of various microorganisms is prevented by lactic fermentation. It is not necessary to cause lactic fermentation with a thing generated naturally and intentionally. The people living in the Dirashe area in southern Ethiopia drink three types of alcoholic beverages that are prepared from cereals. From these alcoholic beverages, parshot is prepared by the addition of plant leaves for lactic fermentation and nech chaka by adding cereal powder for lactic fermentation before alcohol fermentation. People living in the Dirashe area partake of parshot as part of their staple diet. The brewing process used for parshot and a food culture with alcoholic beverages as parts of the staple diet are rare worldwide. This article discusses the significance of using lactic fermentation before alcoholic fermentation and focuses on lactic fermentation in the brewing methods used for the three kinds of alcoholic beverages consumed in the Dirashe area. We initially observed the brewing process and obtained information about the process from the people in that area. Next, we determined the pH and analyzed the lactic acid (g/100 g) and ethanol (g/100 g) content during lactic fermentation of parshot and nech chaka; the ethyl acetate (mg/100 g) and volatile base nitrogen (mg/100 g) content during this period was also analyzed. In addition, we compared the ethanol (g/100 g) content of all three kinds of alcoholic beverages after completion of brewing. The results showed that it was possible to consume large quantities of these alcoholic beverages because of the use of lactic fermentation before alcoholic fermentation, which improved the safety and preservation characteristics of the beverages by preventing the propagation of various microorganisms, improving flavor, and controlling the alcohol level.

Genetic associations and shared environmental effects on the skin microbiome of Korean twins

Background

The skin is the outermost layer of the human body and one of the key sites for host-microbe interactions. Both environmental and host genetic factors influence microbial communities in distinct anatomical niches, but little is known about their interplay in shaping the skin microbiome. Here, we investigate the heritable components of the skin microbiome and their association with host genetic factors.

Results

Based on our analysis of the microbiota from 45 individuals including monozygotic and dizygotic twins aged 26–55 years and their mothers, we found that skin microbial diversity was significantly influenced by age and skin pigmentation. Heritability analysis revealed genetic and shared environmental impacts on the skin microbiome. Furthermore, we observed a strong association between the abundance of Corynebacterium jeikeium and single nucleotide polymorphisms (SNPs) in the host FLG gene related to epidermal barrier function.

Conclusion

This study reveals an intimate association of the human skin microbiome and host genes, and increases our understanding of the role of human genetic factors in establishing a microbial ecosystem on the body surface.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-015-2131-y) contains supplementary material, which is available to authorized users.

Production of biologically active scFv and VHH antibody fragments in Bifidobacterium longum

Bifidobacteria constitute a significant part of healthy intestinal microbiota in adults and infants and present a promising platform for construction of genetically modified probiotic agents for treatment of gastrointestinal disorders. In this study, three strains of Bifidobacterium longum were constructed that express and secrete biologically active single-chain antibodies against human TNF-α and Clostridium difficile exotoxin A. Anti-TNF-α scFv antibody D2E7 was produced at the level of 25 μg L(-1) in broth culture and was mostly retained in the cytoplasm, while VHH-type antibodies A20.1 and A26.8 against C. difficile exotoxin A were produced at the levels of 0.3-1 mg L(-1) and secreted very efficiently. The biological activity of both antibody types was demonstrated in the mammalian cell-based assays. Expression of A20.1 and A26.8 was also observed in vivo after intragastric administration of transformed B. longum strains to (C57/BL6 × DBA/2)F1 mice. The obtained B. longum strains may serve as prototypes for construction of novel probiotic medications against inflammatory bowel disease and C. difficile-associated disease.

Horizontal transfer of antibiotic resistance from Enterococcus faecium of fermented meat origin to clinical isolates of E. faecium and Enterococcus faecalis

Enterococcus species are part of the normal intestinal flora of a large number of mammals including humans and consequently, they can be used as indicators of faecal contamination in food and water for human consumption. Their presence in large numbers in foods may indicate a lapse in sanitation and their ability to serve as a genetic reservoir of transferable antibiotic resistance is of concern. In the present study, Enterococcus spp., isolated from commercially fermented meat and human clinical specimen were studied to determine genetic relationships. SmaI pulsed-field gel electrophoresis (PFGE) patterns exhibited genomic heterogeneity within and between both groups of isolates. However, in spite of this heterogeneity there were still substantial phenotypic similarities which suggested that food might be a potential vehicle for distribution of resistant bacteria among humans. In vitro conjugation experiments demonstrated transfer of the tetracycline resistant determinant, tet(M), from Enterococcus faecium S27 isolated from fermented sausage to clinical isolates of both E. faecium and Enterococcus faecalis. The streptomycin resistance of E. faecium S27 was also transferred to a clinical strain, E. faecalis 82916, which was confirmed by the presence of the streptomycin resistance gene, aadA, in the donor and transconjugant strains. Since the aadA gene is associated with a class 1 integron, results also suggested that resistance transfer might have occurred via an integron. It appears this is the first identification of a class 1 integron in E. faecium isolated from food. The importance of food enterococci as a reservoir of antibiotic resistance genes and the potential for their genetic transfer to human strains following consumption of uncooked or undercooked contaminated meat is underlined by this work.