Emmanouil Angelakis

Comparative meta-analysis of the effect of Lactobacillus species on weight gain in humans and animals

BACKGROUND Obesity is associated with alteration of the gut microbiota. In order to clarify the effect of Lactobacillus-containing probiotics (LCP) on weight we performed a meta-analysis of clinical studies and experimental models. We intended to assess effects by Lactobacillus species. METHODS A broad search with no date or language restriction was performed. We included randomized controlled trials (RCTs) and comparative clinical studies in humans and animals or experimental models assessing the effect of Lactobacillus-containing probiotics on weight. We primarily attempted to extract and use change from baseline values. Data were extracted independently by two authors. Results were pooled by host and by Lactobacillus species and are summarized in a meta-analysis of standardized difference in means (SMDs). RESULTS We identified and included 17 RCTs in humans, 51 studies on farm animals and 14 experimental models. Lactobacillus acidophilus administration resulted in significant weight gain in humans and in animals (SMD 0.15; 95% confidence intervals 0.05-0.25). Results were consistent in humans and animals. Lactobacillus fermentum and Lactobacillus ingluviei were associated with weight gain in animals. Lactobacillus plantarum was associated with weight loss in animals and Lactobacillus gasseri was associated with weight loss both in obese humans and in animals. CONCLUSIONS Different Lactobacillus species are associated different effects on weight change that are host-specific. Further studies are needed to clarify the role of Lactobacillus species in the human energy harvest and weight regulation. Attention should be drawn to the potential effects of commonly marketed lactobacillus-containing probiotics on weight gain.

The relationship between gut microbiota and weight gain in humans

The human gut microbiota is a metabolic organ that is determined by a dynamic process of selection and competition. Age, dietary habits and geographical origin of people have an important impact on the intestinal microbiota. The role of the microbiota is still largely unknown, but the bacteria of the gut flora do contribute enzymes that are absent in humans and play an essential role in the catabolism of dietary fibers. Germ-free mice provide a complementary approach for characterizing the properties of the human gut microbiota. Recently, microbial changes in the human gut were proposed to be one of the possible causes of obesity. This review summarizes the latest research on the association between microbial ecology and host weight.

Vancomycin Treatment of Infective Endocarditis Is Linked with Recently Acquired Obesity

Background Gut microbiota play a major role in digestion and energy conversion of nutrients. Antibiotics, such as avoparcin (a vancomycin analogue), and probiotics, such as Lactobacillus species, have been used to increase weight in farm animals. We tested the effect of antibiotics given for infective endocarditis (IE) on weight gain (WG). Methodology/Principal Findings Forty-eight adults with a definite diagnosis of bacterial IE (antibiotic group) were compared with forty-eight age-matched controls without IE. Their body mass index (BMI) was collected at one month before the first symptoms and one year after hospital discharge. The BMI increased significantly and strongly in vancomycin-plus-gentamycin–treated patients (mean [±SE] kg/m2, +2.3 [0.9], p = 0.03), but not in controls or in patients treated with other antibiotics. Seventeen patients had a BMI increase of ≥10%, and five of the antibiotic group developed obesity. The treatment by vancomycin-plus-gentamycin was an independent predictor of BMI increase of ≥10% (adjusted OR, 6.7; 95% CI, 1.37–33.0; p = 0.02), but not treatment with other antibiotics. Weight gain was particularly high in male patients older than 65 who did not undergo cardiac surgery. Indeed, all three vancomycin-treated patients with these characteristics developed obesity. Conclusions/Significance A major and significant weight gain can occur after a six-week intravenous treatment by vancomycin plus gentamycin for IE with a risk of obesity, especially in males older than 65 who have not undergone surgery. We speculate on the role of the gut colonization by Lactobacillus sp, a microorganism intrinsically resistant to vancomycin, used as a growth promoter in animals, and found at a high concentration in the feces of obese patients. Thus, nutritional programs and weight follow-up should be utilized in patients under such treatment.

Related actions of probiotics and antibiotics on gut microbiota and weight modification

Antibiotics and probiotics are widely used as growth promoters in agriculture. Most antibiotics prescribed in clinical practice are natural products that originate from Streptomyces spp, which were first used as agricultural probiotics. Antibiotics and probiotics both modify the gut microbiota. The effect of a probiotic species on the digestive flora depends on the strain and is largely determined by bacteriocin production. In human beings, as in animals, specific probiotics are associated with weight gain or loss. Improved understanding of the ability of specific probiotics to harvest energy from the host diet might lead to development of new treatments for obesity and malnutrition. In this Review, we present the effects of probiotics and antibiotics on the gut microbiota of human beings and animals and discuss their potential therapeutic use as interventions for weight gain and loss in human beings.

The increase of Lactobacillus species in the gut flora of newborn broiler chicks and ducks is associated with weight gain.

Background A bacterial role in the obesity pandemic has been suspected based on the ingestion of probiotics that can modify the gut flora. The objective of our study was to determine if increased Lactobacillus sp. in the gut flora of newborn broiler chicks and ducks could result in weight gain increase. Methodology Female broiler chicks (Gallus gallus domesticus) and ducks (Anas platyrhynchos domestica) were separated into one control and two experimental groups, and inoculated once or twice with 4×1010 Lactobacillus spp. per animal in PBS, or with PBS alone. Fecal samples were collected before and at 24 hours, 2, 4, 8, 16 and 30 days after the inoculation. DNA was extracted from the stools, and qPCR assays were performed on a MX3000™ system for the detection and quantification of Lactobacillus sp., Bacteroidetes and Firmicutes, using a quantification plasmid. Animals were measured and sacrificed 60 days after the beginning of the experiment, and livers were collected and measured. Principal Findings Chicks inoculated once and twice with Lactobacillus weighed 10.2% (p = 0.0162) and 13.5% (p = 0.0064) more than the control group animals, respectively. Similarly, ducks inoculated once and twice weighed 7.7% (p = 0.05) and 14% (p = 0.035) more than those in the control group, respectively. Liver mass was also significantly higher in inoculated animals compared to the control group. Inoculation with Lactobacillus sp. increased the DNA copies of Lactobacillus spp. and Firmicutes in the stools. Bacteroidetes remained stable, and only the second Lactobacillus sp. inoculation significantly decreased its population in chicks. The ratio of DNA copies of Firmicutes to those of Bacteroidetes increased to as much as 6,4 in chicks and 8,3 in ducks. Conclusions Differences in the intestinal microbiota may precede weight increase, as we found that an increase of Lactobacillus sp. in newborn ducks and chicks preceded the development of weight gain.

Potential for Tick-borne Bartonelloses

Although possible, tick transmission to a vertebrate host has not been proven.

Rapid and Accurate Bacterial Identification in Probiotics and Yoghurts by MALDI‐TOF Mass Spectrometry

Probiotic food is manufactured by adding probiotic strains simultaneously with starter cultures in fermentation tanks. Here, we investigate the accuracy and feasibility of matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS) for bacterial identification at the species level in probiotic food and yoghurts. Probiotic food and yoghurts were cultured in Columbia and Lactobacillus specific agar and tested by quantitative real-time PCR (qPCR) for the detection and quantification of Lactobacillus sp. Bacterial identification was performed by MALDI-TOF analysis and by amplification and sequencing of tuf and 16S rDNA genes. We tested 13 probiotic food and yoghurts and we identified by qPCR that they presented 10(6) to 10(7) copies of Lactobacillus spp. DNA/g. All products contained very large numbers of living bacteria varying from 10(6) to 10(9) colony forming units/g. These bacteria were identified as Lactobacillus casei, Lactococcus lactis, Bifidobacterium animalis, Lactobacillus delbrueckii, and Streptococcus thermophilus. MALDI-TOF MS presented 92% specificity compared to the molecular assays. In one product we found L. lactis, instead of Bifidus spp. which was mentioned on the label and for another L. delbrueckii and S. thermophilus instead of Bifidus spp. MALDI-TOF MS allows a rapid and accurate bacterial identification at the species level in probiotic food and yoghurts. Although the safety and functionality of probiotics are species and strain dependent, we found a discrepancy between the bacterial strain announced on the label and the strain identified. Practical Application:  MALDI-TOF MS is rapid and specific for the identification of bacteria in probiotic food and yoghurts. Although the safety and functionality of probiotics are species and strain dependent, we found a discrepancy between the bacterial strain announced on the label and the strain identified.

Altitude-dependent Bartonella quintana genotype C in head lice, Ethiopia.

To determine the presence of Bartonella quintana in head and body lice from persons in different locations in Ethiopia, we used molecular methods. B. quintana was found in 19 (7%) genotype C head lice and in 76 (18%) genotype A body lice. B. quintana in head lice was positively linked to altitude (p = 0.014).

Pathogenicity and treatment of Bartonella infections

Bartonella spp. are responsible for emerging and re-emerging diseases around the world. The majority of human infections are caused by Bartonella henselae, Bartonella quintana and Bartonella bacilliformis, although other Bartonella spp. have also been associated with clinical manifestations in humans. The severity of Bartonella infection correlates with the patients immune status. Clinical manifestations can range from benign and self-limited to severe and life-threatening disease. Clinical conditions associated with Bartonella spp. include local lymphadenopathy, bacteraemia, endocarditis, and tissue colonisation resulting in bacillary angiomatosis and peliosis hepatis. Without treatment, Bartonella infection can cause high mortality. To date, no single treatment is effective for all Bartonella-associated diseases. In the absence of systematic reviews, treatment decisions for Bartonella infections are based on case reports that test a limited number of patients. Antibiotics do not significantly affect the cure rate in patients with Bartonella lymphadenopathy. Patients with Bartonella spp. bacteraemia should be treated with gentamicin and doxycycline, but chloramphenicol has been proposed for the treatment of B. bacilliformis bacteraemia. Gentamicin in combination with doxycycline is considered the best treatment regimen for endocarditis, and erythromycin is the first-line antibiotic therapy for the treatment of angioproliferative lesions. Rifampicin or streptomycin can be used to treat verruga peruana. In this review, we present recent data and recommendations related to the treatment of Bartonella infections based on the pathogenicity of Bartonella spp.

An evaluation of the effects of Lactobacillus ingluviei on body weight, the intestinal microbiome and metabolism in mice.

BACKGROUND Food can modify the intestinal flora, and Lactobacillus ingluviei has been shown to cause weight gain in chicks and ducks but not in mammals. METHODOLOGY Female BALB/c mice were divided into a control and two experimental groups and were inoculated either once or twice with L. ingluviei or with PBS. Faecal samples were collected and tested using qPCR in order to detect and quantify Lactobacillus spp., Bacteroidetes spp. and Firmicutes spp. Gene expression was examined in liver and adipose tissue by microarray and qPCR. Metabolic indicators in the plasma were also measured. RESULTS Mice that were inoculated with 4 × 10(10) L. ingluviei presented a significant increase in weight gain and liver weight and significant increases in Lactobacillus spp. and Firmicutes DNA copy numbers in their faeces. The mRNA levels of fatty acyl synthase (Fas), sterol regulatory element binding factor 1 (Srebp1c), tumour necrosis factor alpha (Tnf), cytochrome P450 2E1 (Cyp2e1), 3-phosphoinositide-dependent protein kinase-1 (Pdpk1), acyl-Coenzyme A dehydrogenase 11 (Acad11), ATP-binding cassette sub family member G (ABCG2) and DEAD box polypeptide 25 (Ddx25) were significantly elevated in the liver tissues of animals in the experimental group. In gonadal adipose tissue, the expression levels of leptin, peroxisome proliferator-activated receptor γ (Pparg) and Srebp1c were significantly higher in animals from the experimental group, whereas the expression of adiponectin was significantly lower in these animals. CONCLUSIONS The inoculation of L. ingluviei in mice resulted in alterations in the intestinal flora, increased weight gain and liver enlargement, accelerated metabolism and increased inflammation.