Lactobacillus bacteremia, clinical significance, and patient outcome, with special focus on probiotic L. rhamnosus GG

Invisible epidemics: ethics and asymptomatic infection

Interactions between microbes and human hosts can lead to a wide variety of possible outcomes including benefits to the host, asymptomatic infection, disease (which can be more or less severe), and/or death. Whether or not they themselves eventually develop disease, asymptomatic carriers can often transmit disease-causing pathogens to others. This phenomenon has a range of ethical implications for clinical medicine, public health, and infectious disease research. The implications of asymptomatic infection are especially significant in situations where, and/or to the extent that, the microbe in question is transmissible, potentially harmful, and/or untreatable. This article reviews the history and concept of asymptomatic infection, and relevant ethical issues associated with this phenomenon. It illustrates the role and ethical significance of asymptomatic infection in outbreaks, epidemics, and pandemics–including recent crises involving drug resistance, Zika, and Covid19. Serving as the Introduction to this Special Issue of Monash Bioethics Review, it also provides brief summaries of the other articles comprising this collection.

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.

Antibiotic-induced gut dysbiosis and barrier disruption and the potential protective strategies

The oral antibiotic therapies administered widely to people and animals can cause gut dysbiosis and barrier disruption inevitably. Increasing attention has been directed toward antibiotic-induced gut dysbiosis, which involves a loss of diversity, changes in the abundances of certain taxa and consequent effects on their metabolic capacity, and the spread of antibiotic-resistant bacterial strains. Treatment with beta-lactam, glycopeptide, and macrolide antibiotics is associated with the depletion of beneficial commensal bacteria in the genera Bifidobacterium and Lactobacillus. The gut microbiota is a reservoir for antibiotic resistance genes, the prevalence of which increases sharply after antibiotic ingestion. The intestinal barrier, which comprises secretory, physical, and immunological barriers, is also a target of antibiotics. Antibiotic induced changes in the gut microbiota composition could induce weakening of the gut barrier through changes in mucin, cytokine, and antimicrobial peptide production by intestinal epithelial cells. Reports have indicated that dietary interventions involving prebiotics, probiotics, omega-3 fatty acids, and butyrate supplementation, as well as fecal microbiota transplantation, can alleviate antibiotic-induced gut dysbiosis and barrier injuries. This review summarizes the characteristics of antibiotic-associated gut dysbiosis and barrier disruption, as well as the strategies for alleviating this condition. This information is intended to provide a foundation for the exploration of safer, more efficient, and affordable strategies to prevent or relieve antibiotic-induced gut injuries.

Lactic Acid Bacteria: Food Safety and Human Health Applications

Research on lactic acid bacteria has confirmed how specific strains possess probiotic properties and impart unique sensory characteristics to food products. The use of probiotic lactic acid bacteria (LAB) in many food products, thus confers various health benefits to humans when they are frequently consumed in adequate amounts. The advent of functional food or the concept of nutraceuticals objectively places more emphasis on seeking alternatives to limit the use of medications thus promoting the regular consumption of fermented foods. Probiotic use has thus been recommended to fulfill the role of nutraceuticals, as no side effects on human health have been reported. Probiotics and lactic acid bacteria can boost and strengthen the human immune system, thereby increasing its resistance against numerous disease conditions. Consumer safety and confidence in dairy and fermented food products and the desire of the food industry to meet the sensory and health needs of consumers, has thus increased the demand for probiotic starter cultures with exceptional performance coupled with health benefiting properties. The potential of probiotic cultures and lactic acid bacteria in many industrial applications including fermented food products generally affects product characteristics and also serves as health-promoting foods for humans. The alleviation of lactose intolerance in many populations globally has been one of the widely accepted health claims attributed to probiotics and lactic acid bacteria, although many diseases have been treated with probiotic lactic acid bacteria and have been proven with scientific and clinical studies. The aim of our review was to present information related to lactic acid bacteria, the new classification and perspectives on industrial applications with a special emphasis on food safety and human health.

Lactobacillus reuteri DSM 17938 and ATCC PTA 5289 ameliorates chemotherapy-induced oral mucositis

Oral mucositis (OM) is a common complication of cancer therapy, however OM management remains unsatisfactory. There is a growing interest in the therapeutic potential of probiotics in OM due to positive findings of its use in intestinal mucositis. This study aimed to determine the efficacy and safety of the probiotic combination Lactobacillus reuteri DSM 17938 and ATCC PTA 5289 strains in chemotherapy-induced OM. Mice were divided into 4 groups. PBS/water and PBS/LR groups comprised of mice injected with PBS intraperitoneally (i.p.), and were given water or the mixture of L. reuteri (LR) DSM 17938 and ATCC PTA 5289 in water respectively. The 5-FU/water and 5-FU/LR groups comprised of mice injected with 5-FU i.p., and were given water or L. reuteri DSM 17938 and ATCC PTA 5289 in water respectively. Histopathological analysis revealed that the oral epithelia of the 5-FU/water and 5-FU/LR groups were thinner compared to PBS/water and PBS/LR groups. However, epithelial damage was significantly reduced in the 5-FU/LR compared to 5-FU/water group. Additionally, the 5-FU/LR group showed reduced oxidative stress and inflammation in the oral mucosa. We further showed that L. reuteri reduced oxidative stress through the nuclear factor E2-related factor-2 (Nrf-2) signalling. There was no evidence of translocation of L. reuteri systemically. This study demonstrated for the first time that L. reuteri protected oral mucosa against damage induced by chemotherapy.

Fecal Microbiome Alteration May Be a Potential Marker for Gastric Cancer

Although intestinal microbial dysbiosis was confirmed to be associated with many chronic diseases and health status through complicated interaction with the host, the effect on gastric cancer was less studied. In this study, we sequenced the 16S rRNA and 18S rRNA genes of fecal bacteria and fungi, respectively, in 134 gastric cancer patients and 58 healthy controls matched by age and gender. Propensity score matching (PSM) was adopted for adjusting diet habits and lifestyle, and 44 patients and 44 healthy controls (matching population) were enrolled. Serum antibody to H. pylori and metabolites of the matching population were detected. The positive rates of antibody to H. pylori between the patients and the control group did not reach the statistical difference. LEfSe analysis indicated that bacteria were more stable than fungi when adjusting diet and lifestyle. Veillonella, Megasphaera, and Prevotella 7 genus and Streptococcus salivarius subsp. Salivarius, Bifidobacterium dentium, and Lactobacillus salivarius species in bacteria were related to the risk of gastric cancer and showed a good diagnostic value in distinguishing the patients from healthy controls. Streptococcus mitis showed a risk effect for gastric cancer; however, the effect turned into be protective after PSM. Serum L-alanine, L-threonine, and methionol were positively associated with Veillonella and Streptococcus and several fungi genus. Overall, our findings indicated that fecal microbiome constitution alteration may be associated with gastric cancer through influencing the amino acid metabolism.

Probiotics and Coronavirus disease 2019: think about the link

The pandemic of Coronavirus disease 2019 (COVID-19) is rapidly progressing, causing significant morbidity and mortality. Various antiviral drugs, anti-inflammatory drugs and immunomodulators have been tried without substantial clinical benefits. The severe and critical cases of COVID-19 disease are characterised by gut microbiome dysbiosis, immune dysregulation, hyper-inflammation and hypercytokinaemia (cytokine storm). Therefore, the strategies which target these pathophysiological processes may be beneficial. Probiotics are one such strategy that exerts beneficial effects by manipulation of the gut microbiota, suppression of opportunistic pathogens in the gut, decreasing translocation of opportunistic organisms, activation of mucosal immunity and modulation of the innate and adaptive immune response. Probiotics are the potential candidates to be tested in moderate and severe cases of COVID-19 due to several beneficial effects, including easy availability, easy to administer, safe and economical to use.

Lactobacillus rhamnosus Infection: A Single-center 4-year Descriptive Analysis

Introduction:

Lactobacillus rhamnosus is an anaerobic or facultative anaerobic Gram-positive rod that is commonly found in the human gastrointestinal tract and vaginal tract. Infections secondary to L. rhamnosus have not been well illustrated in the literature. The purpose of this study was to describe the clinical courses of patients with L. rhamnosus infection in our institution.

Materials and Methods:

A retrospective chart review was performed on patients with the growth of L. rhamnosus or L. rhamnosus/casei from January 1, 2013, to December 31, 2017.

Results:

Forty-seven patients had growth of L. rhamnosus or L. rhamnosus/casei. Of these, 35 patients were included in the study who received therapy. Twenty patients (57.1%) presented with leukocytosis, 17 (48.5%) with fever, and 15 (42.8%) with abdominal pain. Twenty-three (66.1%) had intra-abdominal infection, 8 (22.3%) were bacteremic, and 4 (11.4%) had mediastinitis. Thirty-three patients (94.3%) had a polymicrobial infection. Eighteen (51.4%) patients had disruption of the gastrointestinal tract, 14 (40.0%) had underlying malignancy, and 11 (31.4%) had prior antibiotic exposure. Twenty (57.1%) patients clinically improved after therapy. However, the overall mortality rate was 56.2%, all of whom died of unrelated causes.

Conclusion:

Lactobacilli are organisms thought to have low pathogenicity. Our study identified cases of L. rhamnosus infections in a population of patients with serious underlying medical conditions.

Intrauterine growth restriction alters growth performance, plasma hormones, and small intestinal microbial communities in growing-finishing pigs

Background

The interaction of the gut microbiota with key metabolic and physiological processes may be associated with poor growth outcomes in animals born with intrauterine growth restriction (IUGR).

Results

Growth performance, plasma hormone concentrations, and intestinal microbiota composition were analyzed in IUGR pigs and in normal birth weight (NBW) pigs when the NBW pigs reached 25, 50, and 100 kg of body weight (BW). Compared to NBW pigs, IUGR pigs had lower initial, weaned, and final BW, and lower average daily gain and average daily feed intake in all the considered time points. In the 25 kg BW group, IUGR pigs had higher concentrations of plasma ghrelin and pancreatic polypeptide (PP), but lower insulin concentration than NBW pigs, while the situation was reversed in the 50 kg BW group. As compared to NBW pigs, IUGR pigs had higher microbial alpha diversity in the jejunum and ileum; in the 50 and 100 kg BW groups, IUGR pigs had higher Firmicutes abundance but lower Proteobacteria abundance in the jejunum, and lower Lactobacillus abundance in the jejunum and ileum; in the 25 kg BW group, IUGR pigs showed higher unclassified Ruminococcaceae abundance in the ileum; and in 25 and 50 kg BW groups, IUGR pigs showed lower Ochrobactrum abundance in the jejunum. Spearman’s correlation revealed that Lactobacillus was negatively correlated with growth performance, while unclassified Ruminococcaceae was positively correlated. Predictive metagenomic analysis detected significantly different expression of genes in the intestinal microbiota between IUGR and NBW pigs, suggesting different metabolic capabilities between the two groups.

Conclusions

Growing-finishing IUGR pigs showed lower growth performance, higher microbial alpha diversity, and differences in plasma hormone concentrations compared to NBW pigs. Alterations in the abundance of Firmicutes, Proteobacteria, Ruminococcaceae, Lactobacillus, and Ochrobactrum in the small intestine may be associated with IUGR, and may therefore serve as a future target for gut microbiota intervention in growing-finishing IUGR pigs.

Lactobacillus acidophilus-Induced Endocarditis and Associated Splenic Abscess

Lactobacillus acidophilus is a rod-shaped, Gram-positive bacterium generally found in the normal flora of the oropharynx, gastrointestinal, and genitourinary tracts. It is commonly known as nonpathogen in the human body. Endocarditis due to Lactobacillus is rarely encountered and associated with impaired immunity. Splenic abscess is also an uncommon infection that classically results from endocarditis or another source of hematogenous seeding. Here, we present the case of bioprosthetic aortic valve endocarditis and associated splenic abscess caused by Lactobacillus acidophilus. The source of the Lactobacillus bacteremia should be investigated because of the risk of life-threatening conditions. Most of the time, identifying Lactobacillus species is challenging and can cause a delay in diagnosis and timely treatment. Especially in patients who have significant underlying clinical conditions, physicians should consider Lactobacillus species as a causative microorganism.

Lactobacillus rhamnosus Bacteremia in an Immunocompromised Renal Transplant Patient

Conventionally, Lactobacillus species are considered as low virulence organisms and rarely cause infection in immunocompetent individuals. However, it might be an opportunistic infection source in immunocompromised patients and can cause invasive serious infections. To our knowledge, there are only a handful of cases in the literature reporting primary bloodstream infection caused by Lactobacilli spp. in transplant recipients. Here, we report a case of a kidney transplant recipient with Lactobacillus rhamnosus bacteremia.

Insights into the role of intestinal microbiota in hematopoietic stem-cell transplantation

The gut microbiota (GM) is able to modulate the human immune system. The development of novel investigation methods has provided better characterization of the GM, increasing our knowledge of the role of GM in the context of hematopoietic stem-cell transplantation (HSCT). In particular, the GM influences the development of the major complications seen after HSCT, having an impact on overall survival. In fact, this evidence highlights the possible therapeutic implications of modulation of the GM during HSCT. Insights into the complex mechanisms and functions of the GM are essential for the rational design of these therapeutics. To date, preemptive and curative approaches have been tested. The current state of understanding of the impact of the GM on HSCT, and therapies targeting the GM balance is reviewed herein.

Genomic and epidemiological evidence of bacterial transmission from probiotic capsule to blood in ICU patients

Probiotics are routinely administered to hospitalized patients for many potential indications1 but have been associated with adverse effects that may outweigh their potential benefits2-7. It is particularly alarming that probiotic strains can cause bacteremia8,9, yet direct evidence for an ancestral link between blood isolates and administered probiotics is lacking. Here we report a markedly higher risk of Lactobacillus bacteremia for intensive care unit (ICU) patients treated with probiotics compared to those not treated, and provide genomics data that support the idea of direct clonal transmission of probiotics to the bloodstream. Whole-genome-based phylogeny showed that Lactobacilli isolated from treated patients' blood were phylogenetically inseparable from Lactobacilli isolated from the associated probiotic product. Indeed, the minute genetic diversity among the blood isolates mostly mirrored pre-existing genetic heterogeneity found in the probiotic product. Some blood isolates also contained de novo mutations, including a non-synonymous SNP conferring antibiotic resistance in one patient. Our findings support that probiotic strains can directly cause bacteremia and adaptively evolve within ICU patients.

Gut microbiotas and immune checkpoint inhibitor therapy response: a causal or coincidental relationship?

As the largest immune organ, human gut microbiome could influence the efficacy of immune checkpoint inhibitor therapy (ICI). However, identifying contributory microbes from over 35,000 species is virtually impossible and the identified microbes are not consistent among studies. The reason for the disparity may be that the microbes found in feces are markers of other factors that link immune response and microbiotas. Notably, gut microbiome is influenced by stool consistency, diet and other lifestyle factors. Therefore, the ICI and microbiotas relationship must be adjusted for potential confounders and analyzed longitudinally. Moreover, a recent study where 11 low-abundance commensal bacteria induced interferon-γ-producing CD8 T cells, challenges the validity of the abundance-oriented microbiotas investigations. This study also confirmed the hierarchy in immunogenic roles among microbiotas. Fecal transplantation trials in germ-free mice provided “the proof of principle” that germ-free mice reproduce the donor’s microbiome and corresponding ICI efficacy. However, species-specific biological differences prevent direct extrapolation between the results in murine and human models. Fecal transplantation or supplementation with microbes found in ICI responders requires caution due to potential adverse events.

Septicemia from Lactobacillus rhamnosus GG, from a Probiotic Enriched Yogurt, in a Patient with Autologous Stem Cell Transplantation

Probiotic-rich foods are consumed without much restriction. We report here, a case of septic shock caused by yogurt derived Lactobacillus species in a 54-year-old male patient with acute promyelocytic leukemia, in second complete remission, and who was an autologous stem cell transplantation recipient. He received high dose chemotherapy and autologous peripheral blood stem cell transplantation. He ingested commercially available probiotic-enriched yogurt because of severe diarrhea. One week later, he developed septic shock, and the pathogen was determined by strain-specific PCR analysis as Lactobacillus rhamnosus GG (ATCC 53103), which was found to be identical with the strain in the yogurt he consumed. Thus, because even low virulent Lactobacilli in the probiotic products can be pathogenic in the compromised hosts, ingestion of such products should be considered with caution in neutropenic patients with severe diarrhea, such as stem cell transplantation recipients.

Presence of OXA-48 Gene in a Clinical Isolate of Lactobacillus rhamnosus

Lactobacilli are part of the microbiota and are also used as probiotics. However, in recent years they have been associated with invasive infections, especially bacteremia. Lactobacillus spp. are usually susceptible to penicillins, macrolides, and carbapenems, but Lactobacillus rhamnosus is intrinsically resistant to glycopeptides. The aim of this study was to determine the antimicrobial susceptibility profile and resistance mechanism of a clinical isolate of L. rhamnosus isolated from 10 sets of blood cultures of the same patient. The isolate was identified by Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (Bruker Daltonics; BD, Bremen, Germany) and 16S rRNA gene sequencing. In vitro susceptibilities to penicillin, ampicillin, imipenem, vancomycin, erythromycin, clindamycin, and linezolid were determined with gradient test strips (bioMérieux, France) on Mueller-Hinton agar plates supplemented with 5% defibrinated horse blood and 20 mg/L β-NAD. The isolate was resistant to vancomycin and imipenem. Polymerase chain reaction test was positive for blaOXA-48 and the presence of this carbapenemase was confirmed by gene sequencing. Although plasmid analysis suggested that the blaOXA-48 is chromosomal in this isolate, it is still an alarming finding for potential transmission of antibiotic resistance genes to other bacteria in the gut. To our knowledge, this is the first report of the presence of blaOXA-48 in a Lactobacillus spp. and has utmost importance as these bacteria are used as probiotics. The isolation of these bacteria from sterile body sites should not go unnoticed.

Lactobacillus paracasei endocarditis of bioprosthetic aortic valve presenting with recurrent embolic strokes

Introduction

Lactobacillus prosthetic valve endocarditis is a rare infection caused by Lactobacillus bacteria. This bacterium is found in the normal flora of the human mouth, gastrointestinal tract and female genital tract. While there have been isolated cases of Lactobacillus bacteraemia and endocarditis, the infections are associated with comorbidities, immune deficiency, dental manipulation procedures and other medical history. This case of bioprosthetic valve endocarditis caused by Lactobacillus paracasei is unusual, as the patient was immune-competent and treated with pre-procedural antibiotics.

Case

We present a case of a 65-year-old male who underwent a dental extraction. He presented after 3 months of fever, chills and fatigue. On initial presentation, blood cultures were positive for alpha-haemolytic streptococcus bacteraemia. He was treated with IV penicillin and underwent aortic valve replacement with a bioprosthetic valve and excision of the mitral vegetation with repair of the mitral valve. Two years later, he had a tooth extraction after being treated properly with antibiotics. Three months later he presented with difficulty speaking, left leg weakness and increased drooling. All testing was normal. Three months later he presented with left side lower extremity weakness and expressive aphasia. He was diagnosed with bioprosthetic aortic valve endocarditis and was treated with IV penicillin and gentamicin for 6 weeks and then switched to oral penicillin. He remained stable.

Conclusions

L. paracasei can potentially be a cause of complicated endocarditis in patients with prosthetic heart valves undergoing dental procedures. Timely culture-guided antibiotic therapy is critical and may obviate the need for valve surgery.

Specific Gut and Salivary Microbiota Patterns Are Linked With Different Cognitive Testing Strategies in Minimal Hepatic Encephalopathy

OBJECTIVES

Minimal hepatic encephalopathy (MHE) is epidemic in cirrhosis, but testing strategies often have poor concordance. Altered gut/salivary microbiota occur in cirrhosis and could be related to MHE. Our aim was to determine microbial signatures of individual cognitive tests and define the role of microbiota in the diagnosis of MHE.

METHODS

Outpatients with cirrhosis underwent stool collection and MHE testing with psychometric hepatic encephalopathy score (PHES), inhibitory control test, and EncephalApp Stroop. A subset provided saliva samples. Minimal hepatic encephalopathy diagnosis/concordance between tests was compared. Stool/salivary microbiota were analyzed using 16srRNA sequencing. Microbial profiles were compared between patients with/without MHE on individual tests. Logistic regression was used to evaluate clinical and microbial predictors of MHE diagnosis.

RESULTS

Two hundred forty-seven patients with cirrhosis (123 prior overt HE, MELD 13) underwent stool collection and PHES testing; 175 underwent inhibitory control test and 125 underwent Stroop testing. One hundred twelve patients also provided saliva samples. Depending on the modality, 59%-82% of patients had MHE. Intertest Kappa for MHE was 0.15-0.35. Stool and salivary microbiota profiles with MHE were different from those without MHE. Individual microbiota signatures were associated with MHE in specific modalities. However, the relative abundance of Lactobacillaceae in the stool and saliva samples was higher in MHE, regardless of the modality used, whereas autochthonous Lachnospiraceae were higher in those without MHE, especially on PHES. On logistic regression, stool and salivary Lachnospiraceae genera (Ruminococcus and Clostridium XIVb) were associated with good cognition independent of clinical variables.

DISCUSSION

Specific stool and salivary microbial signatures exist for individual cognitive testing strategies in MHE. The presence of specific taxa associated with good cognitive function regardless of modality could potentially be used to circumvent MHE testing.

Are Probiotic Really Safe for Humans?

Probiotic bacteria have been used as a health-promoting factor for a very long time. Nowadays, products containing probiotic bacteria are becoming more and more popular on the market. The term probiotics refers to the products belonging to the following groups: probiotic drugs (medicinal products – live biotherapeutic products for human use), medical devices, probiotic foods (e.g. foods, food ingredients, dietary supplements or food for special medical purposes), directly fed microorganisms (for animal use) and designer probiotics (genetically modified probiotics). Safety assessment of bacterial strains used as probiotics should be carefully studied. Even though probiotic bacteria have the generally recognized as safe (GRAS status), there are several reports about side effects triggered by the presence of these organisms. Microorganisms used as probiotics may cause systemic infections, stimulate the immune system, disturb metabolism and participate in horizontal gene transfer.

Members of the Lactobacillus Genus Complex (LGC) as Opportunistic Pathogens: A Review

Microorganisms belonging to the Lactobacillus genus complex (LGC) are naturally associated or deliberately added to fermented food products and are widely used as probiotic food supplements. Moreover, these bacteria normally colonize the mouth, gastrointestinal (GI) tract, and female genitourinary tract of humans. They exert multiple beneficial effects and are regarded as safe microorganisms. However, infections caused by lactobacilli, mainly endocarditis, bacteremia, and pleuropneumonia, occasionally occur. The relevance of Lactobacillus spp. and other members of the LGC as opportunistic pathogens in humans and related risk factors and predisposing conditions are illustrated in this review article with more emphasis on the species L. rhamnosus that has been more often involved in infection cases. The methods used to identify this species in clinical samples, to distinguish strains and to evaluate traits that can be associated to pathogenicity, as well as future perspectives for improving the identification of potentially pathogenic strains, are outlined.

Probiotics for the prevention of pediatric antibiotic-associated diarrhea

BACKGROUND

Antibiotics alter the microbial balance commonly resulting in antibiotic-associated diarrhea (AAD). Probiotics may prevent AAD via providing gut barrier, restoration of the gut microflora, and other potential mechanisms of action.

OBJECTIVES

The primary objectives were to assess the efficacy and safety of probiotics (any specified strain or dose) used for the prevention of AAD in children.

SEARCH METHODS

MEDLINE, Embase, CENTRAL, CINAHL, and the Web of Science (inception to 28 May 2018) were searched along with registers including the ISRCTN and Clinicaltrials.gov. We also searched the NICE Evidence Services database as well as reference lists from relevant articles.

SELECTION CRITERIA

Randomized, parallel, controlled trials in children (0 to 18 years) receiving antibiotics, that compare probiotics to placebo, active alternative prophylaxis, or no treatment and measure the incidence of diarrhea secondary to antibiotic use were considered for inclusion.

DATA COLLECTION AND ANALYSIS

Study selection, data extraction, and risk of bias assessment were conducted independently by two authors. Dichotomous data (incidence of AAD, adverse events) were combined using a pooled risk ratio (RR) or risk difference (RD), and continuous data (mean duration of diarrhea) as mean difference (MD), along with corresponding 95% confidence interval (95% CI). We calculated the number needed to treat for an additional beneficial outcome (NNTB) where appropriate. For studies reporting on microbiome characteristics using heterogeneous outcomes, we describe the results narratively. The certainty of the evidence was evaluated using GRADE.

MAIN RESULTS

Thirty-three studies (6352 participants) were included. Probiotics assessed included Bacillus spp., Bifidobacterium spp., Clostridium butyricum, Lactobacilli spp., Lactococcus spp., Leuconostoc cremoris, Saccharomyces spp., orStreptococcus spp., alone or in combination. The risk of bias was determined to be high in 20 studies and low in 13 studies. Complete case (patients who did not complete the studies were not included in the analysis) results from 33 trials reporting on the incidence of diarrhea show a precise benefit from probiotics compared to active, placebo or no treatment control.After 5 days to 12 weeks of follow-up, the incidence of AAD in the probiotic group was 8% (259/3232) compared to 19% (598/3120) in the control group (RR 0.45, 95% CI 0.36 to 0.56; I² = 57%, 6352 participants; NNTB 9, 95% CI 7 to 13; moderate certainty evidence). Nineteen studies had loss to follow-up ranging from 1% to 46%. After making assumptions for those lost, the observed benefit was still statistically significant using an extreme plausible intention-to-treat (ITT) analysis, wherein the incidence of AAD in the probiotic group was 12% (436/3551) compared to 19% (664/3468) in the control group (7019 participants; RR 0.61; 95% CI 0.49 to 0.77; P <0.00001; I² = 70%). An a priori available case subgroup analysis exploring heterogeneity indicated that high dose (≥ 5 billion CFUs per day) is more effective than low probiotic dose (< 5 billion CFUs per day), interaction P value = 0.01. For the high dose studies the incidence of AAD in the probiotic group was 8% (162/2029) compared to 23% (462/2009) in the control group (4038 participants; RR 0.37; 95% CI 0.30 to 0.46; P = 0.06; moderate certainty evidence). For the low dose studies the incidence of AAD in the probiotic group was 8% (97/1155) compared to 13% (133/1059) in the control group (2214 participants; RR 0.68; 95% CI 0.46 to 1.01; P = 0.02). Again, assumptions for loss to follow-up using an extreme plausible ITT analysis was statistically significant. For high dose studies the incidence of AAD in the probiotic group was 13% (278/2218) compared to 23% (503/2207) in control group (4425 participants; RR 0.54; 95% CI 0.42 to 0.70; P <0.00001; I² = 68%; moderate certainty evidence).None of the 24 trials (4415 participants) that reported on adverse events reported any serious adverse events attributable to probiotics. Adverse event rates were low. After 5 days to 4 weeks follow-up, 4% (86/2229) of probiotics participants had an adverse event compared to 6% (121/2186) of control participants (RD 0.00; 95% CI -0.01 to 0.01; P < 0.00001; I² = 75%; low certainty evidence). Common adverse events included rash, nausea, gas, flatulence, abdominal bloating, and constipation.After 10 days to 12 weeks of follow-up, eight studies recorded data on our secondary outcome, the mean duration of diarrhea; with probiotics reducing diarrhea duration by almost one day (MD -0.91; 95% CI -1.38 to -0.44; P <0.00001; low certainty evidence). One study reported on microbiome characteristics, reporting no difference in changes with concurrent antibiotic and probiotic use.

AUTHORS' CONCLUSIONS

The overall evidence suggests a moderate protective effect of probiotics for preventing AAD (NNTB 9, 95% CI 7 to 13). Using five criteria to evaluate the credibility of the subgroup analysis on probiotic dose, the results indicate the subgroup effect based on high dose probiotics (≥ 5 billion CFUs per day) was credible. Based on high-dose probiotics, the NNTB to prevent one case of diarrhea is 6 (95% CI 5 to 9). The overall certainty of the evidence for the primary endpoint, incidence of AAD based on high dose probiotics was moderate due to the minor issues with risk of bias and inconsistency related to a diversity of probiotic agents used. Evidence also suggests that probiotics may moderately reduce the duration of diarrhea, a reduction by almost one day. The benefit of high dose probiotics (e.g. Lactobacillus rhamnosus orSaccharomyces boulardii) needs to be confirmed by a large well-designed multi-centered randomized trial. It is premature to draw firm conclusions about the efficacy and safety of 'other' probiotic agents as an adjunct to antibiotics in children. Adverse event rates were low and no serious adverse events were attributable to probiotics. Although no serious adverse events were observed among inpatient and outpatient children, including small studies conducted in the intensive care unit and in the neonatal unit, observational studies not included in this review have reported serious adverse events in severely debilitated or immuno-compromised children with underlying risk factors including central venous catheter use and disorders associated with bacterial/fungal translocation.

Meningoencephalitis caused by Lactobacillus plantarum - case report

Specific strains of Lactobacillus spp. are widely used as probiotic agents but it has been repeatedly reported that may have a pathogenic potential. We present the report on a case of meningoencephalitis caused by Lactobacillus plantarum in a 63-year-old man with newly diagnosed metastatic planoepitheliale lung cancer. The patient was hospitalised due to newly diagnosed cancer and during the course of hospitalisation developed symptoms of neuroinfection. On the basis of the symptoms and results of the conducted tests the patient was diagnosed with bacterial meningoencephalitis. In microbiological tests of the blood and cerebrospinal fluid L. plantarum was cultured. During the course of antibiotic therapy the patient's condition improved. Lactobacilli are now recognised as a causative agent of infection, most notably bacteraemia. To our knowledge, this is the fourth documented case of Lactobacillus-associated neuroinfection, and only the second in an adult. Lactobacilli cause mostly opportunistic infections in immunocompromised individuals.

Possible Probiotic Lactic Acid Bacteria Isolated from Oysters (Crassostrea gigas)

We attempted to isolate lactic acid bacteria (LAB) from the marine oyster (Crassostrea gigas) and selected several environmental stress-resistant isolates for the development of a future probiotic adjuvant for marine aquaculture. Twenty-six presumptive LAB isolates were extracted from oysters and screened (by an agar diffusion assay) for antimicrobial activity toward various pathogens: Vibrio parahaemolyticus, Streptococcus iniae, and Edwardsiella tarda. Eight isolates had an antibacterial activity toward V. parahaemolyticus; in particular, 6 isolates showed a growth-inhibitory activity, with inhibition zone diameters > 15 mm. Of these, 5 isolates (JL17, JL18, JL28, HL7, and HL32) were also active against S. iniae and E. tarda. Enterococcus faecium HL7 was selected as the isolate most resistant to environmental stressors: the minimum NaCl, ethanol, and hydrogen peroxide concentrations at which HL7 cells lost their viability were 1.9 M, 11%, and 0.013%, respectively. When an antibiotic sensitivity test was performed on E. faecium HL7, this isolate was found to be resistant to trimethoprim/sulfamethoxazole, cephalothin, ampicillin, rifampin, gentamicin, cefotaxime, cefepime, cefotetan, nalidixic acid, and kanamycin. While the oyster model studies provided indication that E. faecium HL7 could be a good candidate as biocontrol agent against V. vulnificus, further optimization is needed in the actual animal rearing situation.

Lack of mutagenicity, genotoxicity and developmental toxicity in safety assessment tests of Lactobacillus mali APS1

Lactobacillus (L.) mali APS1 isolated from sugary kefir grains has been proven to affect energy and glucose homeostasis. However, without proper safety assessment it cannot be recommended as probiotics for human consumption. For genotoxicity, the Ames test showed no mutagenic effect of L. mali APS1 in the presence or absence of S9 mix metabolic activation. In-vitro mammalian chromosomal aberration test showed that the number of Chinese hamster ovary cells with abnormal chromosomes was <5% after L. mali APS1 treatment. Moreover, L. mali APS1 showed no risk of genotoxicity potential compared to the control. L. mali APS1 administration did not cause significant (p>0.05) changes in body weight, the number of reticulocytes, or in the occurrence percentage of micronucleus in Imprinting Control Region (ICR) mice. Based on the absence of maternal or fetal effects at any dosage level investigated, the teratogenicity could be defined as greater than 1,670 mg/kg b.w./day for maternal general toxicity and fetal development when L. mali APS1 was orally administered by gavage to pregnant SD rats during gestation days 6 to 15.

Assessing safety of Lactobacillus plantarum MTCC 5690 and Lactobacillus fermentum MTCC 5689 using in vitro approaches and an in vivo murine model

Lactobacilli have a long history of safe use in human nutrition, however, inclusion of any new strain, despite its safe usage evidence, warrants proper analysis of its safety and toxicity under the purview of existing regulations. In the present investigation, Lactobacillus plantarum MTCC 5690 and Lactobacillus fermentum MTCC 5689 were evaluated for their safety and toxicity using both in vitro and in vivo approaches. The in vitro assays included mucin degradation, hemolytic activity, biogenic amine production and platelet aggregation assay. The safety was also assessed using acute, subacute and subchronic assays, bacterial translocation studies, intravenous and intravenous administration and genotoxicity assay in murine model. The outcome of this toxicological safety assessment indicated that both the test strains lacked any harmful metabolic activity or any genotoxic effects. Furthermore, the results of oral toxicity studies in mice revealed that short term administration of high cell mass concentration of 10¹² cfu/animal as well as long term feeding of the probiotic strains did not alter any hematological, general health parameters or cause any organ specific disorder. Based upon these scientific assessments and supported by long history of safe use, both MTCC 5690 and MTCC 5689 may be considered safe for human consumption.

Mitral Valve Endocarditis due to Lactobacillus

Lactobacillus species are Gram-positive, facultative anaerobic, rod-shaped bacteria. They belong to the lactic acid bacteria group and are also known as a usual part of the normal flora of the gastrointestinal tract as well as of the urinary and genital tracts. They are an infrequent human pathogen but can induce several infections such as bacteremia and infectious endocarditis. We report the case of an 81-year-old woman with Lactobacillus bacteremia and mitral valve endocarditis as well as splenic abscesses.

Probiotics in Gastroenterology: How Pro Is the Evidence in Adults?

Probiotic usage has become popular with both medical practitioners and the community in general; patients commonly seek advice regarding what, if any, such preparation would be useful for their own diseases. Since such advice should be evidence-based, identified randomized clinical trials (RCTs) for a number of gastrointestinal conditions were reviewed; the data were organized by individual probiotic genera/species. Only trials in adults were considered. Most of the identified RCTs were small and low-quality, so any conclusions to be drawn will be limited at least by methodologic problems. Using the GRADE system to consider the reliability of the evidence generated from these RCTs, it did appear that the use of fecal microbial transplantation to treat recurrent Clostridium difficile infection is well justified. Given the methodologic issues, there was moderately good evidence for preventing antibiotic-associated diarrhea with Lactobacillus, Bifidobacterium, Streptococcus, or Saccharomyces boulardii and for using Lactobacillus, Bifidobacterium, or Saccharomyces as adjunct therapy in the treatment of Helicobacter pylori. There were other conditions for which some supportive evidence was available. These conditions include VSL#3 for maintaining remissions in patients with pouchitis or treating active ulcerative colitis (UC), fecal microbial transplantation for treating active UC, Bifidobacterium for treating patients with UC in remission, Lactobacillus in patients with painful diverticulosis, a variety of probiotics (Lactobacillus, Bifidobacterium, Streptococcus, or VSL#3) in patients with minimal hepatic encephalopathy, and providing synbiotics to patients postoperatively after liver transplantation. Unfortunately, other limitations in the evidence made it very likely that future research will have an effect on the estimated benefit; these interventions cannot yet be recommended for routine use.

Effects of Live and Heat-Inactivated E. coli Strains and Their Supernatants on Immune Regulation in HT-29 Cells

Probiotics are considered to have a beneficial impact on humans, but in some cases, administration of live microorganisms might be risky. In the present study, immunomodulatory effects of different Escherichia coli strains and their super-natants were examined under different inflammatory conditions with living and heat-inactivated strains. HT-29 cells were incubated with E. coli strains (S2-G1, S2-G3, S2-G4 and S2-G8) and their supernatants with or without stimulation with tumor necrosis factor alpha (TNF-α) or interleukin (IL)-1β. Quantification of IL-8 secretion and gene expression was performed by enzyme-linked immunosorbent assay (ELISA) and real-time polymerase chain reaction (PCR). IL-8 secretion by TNF-α- and IL-1β-stimulated cells was attenuated by all four live strains. In contrast, heat inactivation resulted in an elevated IL-8 expression and secretion in unstimulated cells and did not maintain the anti-inflammatory effect of live bacteria in cytokine-stimulated cells. The supernatant of the live S2-G3 led to an elevated IL-8 secretion in unstimulated and IL-1β-stimulated cells but not in TNF-α-stimulated cells. Live bacteria of all strains might induce an immunosuppressive effect after stimulation of HT-29 cells, whereas heat inactivation and the supernatant seem to induce an elevated immune response. These findings might have an impact depending on the indication and purpose of administration.

Spontaneous Bacterial Peritonitis due to Lactobacillus paracasei in Cirrhosis

Lactobacillus species colonize the human gastrointestinal tract and are rarely pathogenic. We present a case involving a cirrhotic patient who presented with sepsis and was found to have peritoneal cultures demonstrating Lactobacillus as the sole pathogen concerning for spontaneous bacterial peritonitis. Treatment was achieved with high-dose penicillin and clindamycin but the patient developed hepatorenal syndrome and died from acute renal failure. Intra-abdominal Lactobacillus infections are typically seen in patients undergoing peritoneal dialysis or who have recently had bowel perforation. There are few case reports of spontaneous Lactobacillus peritonitis in patients with cirrhosis. Our case report addresses the challenges of Lactobacillus treatment and suggests antibiotic coverage of commensal organisms in patients who do not improve with standard management.

Probiotics and infective endocarditis in patients with hereditary hemorrhagic telangiectasia: a clinical case and a review of the literature

Background

In the last decades, probiotics have been widely used as food supplements because of their putative beneficial health effects. They are generally considered safe but rare reports of serious infections caused by bacteria included in the definition of probiotics raise concerns on their potential pathogenic role in patients with particular predisposing factors. Patients with hereditary hemorrhagic telangiectasia (HHT) are exposed to infections because of telangiectasias and arteriovenous malformations (AVMs). We describe what is, to our knowledge, the first case of infective endocarditis (IE) caused by Lactobacillus rhamnosus in a patient with HHT. A systematic review of the relevant medical literature is presented.

Case presentation

A patient with HHT and an aortic bioprosthesis was admitted because of prolonged fever not responding to antibiotics. The patient had a history of repeated serious infections with hospitalizations and prolonged use of antibiotics, and used to assume large amounts of different commercial products containing probiotics. Weeks before the onset of symptoms the patient had been treated with nasal packings and with surgical closure of a nasal bleeding site because of recurrent epistaxis. A diagnosis of IE of the aortic bioprosthesis was made. All blood coltures were positive for L. rhamnosus. The patients responded to a cycle of 6 weeks of amoxicillin/clavulanate plus gentamicin. A systematic review of IE linked to consumption of probiotics, and of infective endocarditis in patients with HHT was conducted. 10 cases of IE linked to probiotics consumption and 6 cases of IE in patients with HHT were found.

Conclusions

Consumption of probiotics can pose a risk of serious infections in patients with particular predisposing factors. Patients with HHT can be considered at risk because of their predisposition to infections. Prophylaxis with antibiotics before nasal packings in patients with HHT can be considered.

Electronic supplementary material

The online version of this article (10.1186/s12879-018-2956-5) contains supplementary material, which is available to authorized users.

Recurrent Lactobacillus Bacteremia in a Patient With Leukemia

Lactobacillus species are a commensal flora of the human gastrointestinal and the female genitourinary tract. Lactobacilli especially the rhamnosus species, are common components of commercial probiotics. They are rarely associated with pathology in immunocompetent people, but they have been known to cause dental caries, bacteremia, and endocarditis in patients with suppressed immune function. Cases of Lactobacillus bacteremia have been reported in patients with acute myeloid leukemia, large granular lymphocytic leukemia, and in transplant recipients. In this article, we report a strange case of recurrent Lactobacillus bacteremia causing multiple episodes of fever of unknown origin in a patient with leukemia. This report is unique as Lactobacillus is not recognized as a common source of bacteremia. Moreover, the source of the bacillus continued to elude us even after extensive investigation.

Probiotics for Trauma Patients: Should We Be Taking a Precautionary Approach?

The use of probiotics in the hospital setting is largely understudied and highly controversial. Probiotics are living organisms that, when taken internally, can produce an immunomodulating effect and improve the gastrointestinal (GI) mucosal barrier. Although used for centuries by healthy individuals for GI health, their use in the hospital setting is now gaining wide attention for the prevention of infectious complications such as antibiotic-associated diarrhea, Clostridium difficile infections, multiple-organ dysfunction syndrome, and ventilator-associated pneumonia. However, current understanding of the efficacy of probiotics in the acute care setting is confounded by the inconsistencies in the literature with regard to the strain of probiotic being studied, optimal dosage, and timing and duration of dosing, which make the formulation of clinical practice guidelines difficult. Although the safety of probiotics has been confirmed when used for the prevention and treatment of certain diseases, practitioners remain hesitant to administer them to their patients, citing the lack of high-quality studies clearly demonstrating efficacy and safety. Infection is a cause of late death in trauma patients, but only recently has research been conducted on the use of probiotics specifically for the prevention of hospital-acquired infections in trauma patients. In the face of such limited but promising research, is it reasonable to use probiotics for the prevention of infection in hospitalized trauma patients and improve outcomes? Use of the "precautionary principle" may be useful in this instance.

Lactobacillus rhamnosus GG: An Overview to Explore the Rationale of Its Use in Cancer

Cancer is the second leading cause of death in the western world. In the era of precision medicine, a significant number of cancer patients can be cured with several anti-cancer therapeutic regimens. However, therapy failure may be caused by treatment side effects, such as diarrhea, especially occurring in patients with gastrointestinal or pelvic malignancies. In particular, diarrhea is one of the most frequent gastrointestinal toxicity during cancer treatment and it can result from nearly bot chemo- and radio-therapeutic strategies currently used. Diarrhea has a serious impact on patients’ quality of life and treatment dosing and schedule modification due to its severity can negatively influence treatment outcomes. In this context, probiotics may play an interesting role in several human diseases with an inflammatory bowel involvement and, among these, Lactobacillus rhamnosus GG (LGG) is one of the most characterized and utilized. In particular, LGG is able to reverse intestinal dysbiosis and moderate diarrhea. Moreover, preclinical studies have documented its effects in reducing chronic inflammation associated with cancer development. This review summarizes the preclinical results of LGG on cancer cells proliferation and tumor invasion as well as the potential role of LGG use in cancer patients for the prevention and management of diarrhea associated with cancer treatment. Overall, these encouraging data support further investigation on the use of LGG in stratified patients undergoing specific therapeutic protocols, including chemotherapy and pelvic radiotherapy, in order to reduce the development of severe diarrhea and thus improve the adherence to the therapy and patients’ quality of life.

The function of probiotics on the treatment of ventilator-associated pneumonia (VAP): facts and gaps

Probiotics have been used for centuries in making fermented dairy products. The health benefits related to probiotics consumption are well recognized and they are generally regarded as safe (GRAS). Their therapeutic effects are due to the production of a variety of antimicrobial compounds, such as short-chain fatty acids, organic acids (such as lactic, acetic, formic, propionic and butyric acids), ethanol, hydrogen peroxide and bacteriocins. Ventilator-associated pneumonia (VAP) is a nosocomial infection associated with high mortality in intensive care units. VAP can result from endotracheal intubation and mechanical ventilation. These interventions increase the risk of infection as patients lose the natural barrier between the oropharynx and the trachea, which in turn facilitates the entry of pathogens through the aspiration of oropharyngeal secretions containing bacteria into the lung. In order to prevent this, probiotics have been used extensively against VAP. This review is an update containing information extracted from recent studies on the use of probiotics to treat VAP. In addition, probiotic safety, the therapeutic properties of probiotics, the probiotic strains used and the action of the probiotics mechanism are reviewed. Furthermore, the therapeutic effects of probiotic treatment procedures for VAP are compared to those of antibiotics. Finally, the influences of bacteriocin on the growth of human pathogens, and the side-effects and limitations of using probiotics for the treatment of VAP are addressed.

Effect of probiotic strain Lactobacillus acidophilus (LBKV-3) on fecal residual lactase activity in undernourished children below 10 years

Clinically proven Lactobacillus acidophilus strain LBKV-3 intended as probiotic for humans was used to test its effect on fecal residual lactase activity in undernourished children below 10 years of age. The children were selected from malnutrition-declared area of Maharashtra (India). One of the major causes of malnutrition is lactose intolerance which leads to diarrhea. The basic consideration in selecting the probiotic strain of L. acidophilus (LBKV-3) in this investigation was the fact that the organism is isolated from human vaginal surface swab and it was found extensively studied for probiotic characteristic. LBKB₃ is tested by several workers as probiotic for hypocholesterolemic activity, implantation ability, therapeutic effects on gastrointestinal (GI) and related ailments. The results of present investigation have shown that the fecal residual lactase activity significantly increased than its initial value (which was almost zero). It appeared that the fecal residual β-galactosidase activity is an indication of positive implementation abilities of the cultures under investigation. These trends were compared with the control and blank group of children receiving Dahi and buffalo milk (BM). It was observed that both these products failed to exert any significant impact on increase in residual lactase activity.

Assessing the Safety of Expanded Polytetrafluoroethylene Synthetic Grafts in Living Donor Liver Transplantation: Graft Migration Into Hollow Viscous Organs - Diagnosis and Treatment Options

Background

Our recent studies have highlighted the importance and safety of backtable venoplasty for middle hepatic vein (MHV) and inferior right hepatic veins (IRHV) reconstruction using expanded polytetrafluoroethylene (ePTFE) vascular grafts. In this study, we aim to analyze the complications associated with ePTFE graft use and discuss the management of the rare, but, potentially life threatening complications directly related to ePTFE conduits.

Material/Methods

From January 2012 to October 2015 a total of 397 patients underwent living donor liver transplantation (LDLT). The ePTFE vascular grafts were used during the backtable venoplasty for outflow reconstruction in 262 of the liver allografts. Recipients who developed ePTFE-related complications were analyzed.

Results

ePTFE-related complications developed in 1.52% (4/262) of the patients. One patient (0.38%) developed complete thrombosis with sepsis at 24 months post-transplantation and died due to multiorgan failure. Three patients (1.1%) developed graft migration into the second portion of the duodenum, without overt peritonitis. Surgical exploration and ePTFE graft removal was done in all the patients. One patient died due to overwhelming sepsis.

Conclusions

ePTFE graft migration into the duodenum causing perforation is a new set of complications that has been recently described in LDLT and can be treated effectively by surgical removal of the infected vascular graft and duodenal perforation closure. Despite of such complications, in our experience, ePTFE use in LDLT continues to have wide safety margin, with a complication rate of only 1.52%.

The inhibitory impacts of Lactobacillus rhamnosus GG-derived extracellular vesicles on the growth of hepatic cancer cells

Bacterial extracellular vesicles (EVs) have come forth into notice as possible important agent to mediate host-pathogen interactions. In this scientific research, the authors have tried to find out the effect of EVs derived from Lactobacillus rhamnosus GG (LDEVs) on the apoptosis induction in HepG2 cell line. The EVs were purified from the conditioned medium of Lactobacillus rhamnosus GG using ultrafiltration and confirmed by transmission electron microscopy (TEM). The HepG2 cells were treated with different concentrations of purified LDEVs and the cytotoxicity and their effects on the expression of bcl-2 and bax genes were assessed by the MTT assay and semi-quantitative RT-PCR, respectively. The MTT assay showed that only 100 μg/ml of LDEVs had a significant cytotoxic effect on cancer cells (p < 0.05). The apoptotic index (bax/bcl2 expression ratio) was significantly increased after treating with 50 and 100 μg/ml LDEVs (p < 0.05). Increased bax/bcl-2 ratio was led to cancer cell death.

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.

Defence factors of vaginal lactobacilli

Accurate knowledge of the composition and ecology of the vaginal microbial environment in healthy women is necessary for understanding lactobacilli-dominated normal microbiota and the mechanisms by which it reduces disease risk. The vagina and its microbiota form a balanced ecosystem; any movement outside the normal range for this ecosystem of obligate and/or facultative microbes, termed dysbacteriosis, can lead to infection and disease. This review summarizes recent research on the vaginal ecosystem, the Lactobacillus species that dominate it, and the means by which they suppress the growth, development, and/or proliferation of pathogenic microbial species. Lactobacilli colonization is believed to be beneficial since it prevents other microorganisms from colonizing the vaginal epithelium via competitive adhesion, interactions with the local immunity and plasminogen-plasmin system, and the production of lactic acid, hydrogen peroxide, and antibacterial substances. In addition, lactobacilli also constitute an important part of the urogenital tract microbiota and the lactobacilli-dominated vaginal microbiome is a major determinant for female urogenital health.

Lactobacillus coryniformis Causing Pulmonary Infection in a Patient with Metastatic Small Cell Carcinoma: Case Report and Review of Literature on Lactobacillus Pleuro-Pulmonary Infections

Lactobacilli are normal commensals of the gastrointestinal and female genital tract. Due to its low virulence these bacteria are known to cause opportunistic infections. They cause mostly bacteraemia with or without endocarditis and rarely cause pleuro-pulmonary infection. We report a case of Lactobacillus coryniformis pleuro-pulmonary infection and review 14 previously reported cases of lactobacilli causing pleuro-pulmonary infections. Our patient had small cell carcinoma with metastasis. All the 14 cases had pre-existing risk factors like immunosuppresion, cancer or chronic disease. There was no consensus on choice of antimicrobial agents to be used. Different species of lactobacilli were involved. Available susceptibility data showed that lactobacilli species were more susceptible to ampicillin, erythromycin, gentamycin, and clindamycin and decreased to ceftriaxone, ciprofloxacin and trimethoprim-sulphamethoxazole. Isolation of Lactobacillus species from a case of pleuro-pneumonia infection could be a marker of poor long-term prognosis. The diagnosis of these infections requires both microbiologist and clinical correlation to rule out contamination.

Nutrition Issues in Hematopoietic Stem Cell Transplantation: State of the Art

There have been many changes in hematopoietic stem cell transplantation (HSCT) that affect the patient's nutrition support. In the early 1970s, allogeneic transplants were the most common types of HSCTs; today, autologous transplants are the most common. Bone marrow, peripheral blood, and umbilical cord blood all now serve as sources of stem cells. Conditioning therapies include myeloablative, reduced-intensity myeloablative, and nonmyeloablative regimens. New medications are being developed and used to minimize the toxicities of the conditioning therapy and to minimize infectious complications. Supportive therapies for renal and liver complications have changed. In the past, HSCT patients received parenteral nutrition (PN) throughout their hospitalization and sometimes as home therapy. Because of medical complications and cost issues associated with PN, many centers are now working to use less PN and increase use of enteral nutrition. The immunosuppressed diet has changed from a sterile diet prepared under laminar-flow hoods to a more liberal diet that avoids high-risk foods and emphasizes safety in food handling practices. This article will review these changes in HSCT and the impact of these changes on the nutrition support of the patient.