Microbiological characteristics of bloodstream infections in a reference hospital in northeastern Brazil

Routine blood culture is used for the detection of bloodstream infections by aerobic and anaerobic bacteria and by common pathogenic yeasts. A retrospective study was conducted in a public hospital in Maceió-AL, by collecting data of all medical records with positive blood cultures. Out of the 2,107 blood cultures performed, 17% were positive with Staphylococcus coagulase negative (51.14%), followed by Staphylococcus aureus (11.21%) and Klebsiella pneumoniae (6.32%). Gram-positive bacteria predominated among positive blood cultures, highlighting the group of Staphylococcus coagulase-negative. While Gram-negative bacteria had a higher number of species among positive blood cultures.

Characterization of the Composition and Biological Activity of the Venom from Vespa bicolor Fabricius, a Wasp from South China

We analyzed, for the first time, the major components and biological properties of the venom of Vespa bicolor, a wasp from South China. Using HPLC and SDS-PAGE, combined with LC–MS/MS, MALDI-TOF-MS, and NMR data to analyze V. bicolor venom (VBV), we found that VBV contains three proteins (hyaluronidase A, phospholipase A1 (two isoforms), and antigen 5 protein) with allergenic activity, two unreported proteins (proteins 5 and 6), and two active substances with large quantities (mastoparan-like peptide 12a (Vb-MLP 12a), and 5-hydroxytryptamine (5-HT)). In addition, the antimicrobial activity of VBV was determined, and results showed that it had a significant effect against anaerobic bacteria. The minimum inhibitory concentration and minimum bactericidal concentration for Propionibacterium acnes were 12.5 µg/mL. Unsurprisingly, VBV had strong antioxidant activity because of the abundance of 5-HT. Contrary to other Vespa venom, VBV showed significant anti-inflammatory activity, even at low concentrations (1 µg/mL), and we found that Vb-MLP 12a showed pro-inflammatory activity by promoting the proliferation of RAW 264.7 cells. Cytotoxicity studies showed that VBV had similar antiproliferative effects against all tested tumor cell lines (HepG2, Hela, MCF-7, A549, and SASJ-1), with HepG2 being the most susceptible. Overall, this study on VBV has high clinical importance and promotes the development of Vespa bicolor resources.

Lesion Material From Treponema-Associated Hoof Disease of Wild Elk Induces Disease Pathology in the Sheep Digital Dermatitis Model

A hoof disease among wild elk (Cervus elaphus) in the western United States has been reported since 2008. Now present in Washington, Oregon, Idaho, and California, this hoof disease continues to spread among elk herds suggesting an infectious etiology. Causing severe lesions at the hoof-skin junction, lesions can penetrate the hoof-horn structure causing severe lameness, misshapen hooves, and in some cases, sloughed hooves leaving the elk prone to infection, malnutrition, and premature death. Isolated to the feet, this disease has been termed treponeme-associated hoof disease due to the numerous Treponema spp. found within lesions. In addition to the Treponema spp., treponeme-associated hoof disease shares many similarities with digital dermatitis of cattle and livestock including association with several groups of anaerobic bacteria such as Bacteroides, Clostridia, and Fusobacterium, neutrophilic inflammatory infiltrate, and restriction of the disease to the foot and hoof tissues. To determine if there was a transmissible infectious component to this disease syndrome, elk lesion homogenate was used in a sheep model of digital dermatitis. Ten animals were inoculated with lesion material and lesion development was followed over 7 weeks. Most inoculated feet developed moderate to severe lesions at 2- or 4-weeks post-inoculation timepoints, with 16 of 18 feet at 4 weeks also had spirochetes associated within the lesions. Histopathology demonstrated spirochetes at the invading edge of the lesions along with other hallmarks of elk hoof disease, neutrophilic inflammatory infiltrates, and keratinocyte erosion. Treponema-specific PCR demonstrated three phylotypes associated with elk hoof disease and digital dermatitis were present. Serum of infected sheep had increased anti-Treponema IgG when compared to negative control sheep and pre-exposure samples. Analysis of the bacterial microbiome by sequencing of the bacterial 16S rRNA gene showed a community structure in sheep lesions that was highly similar to the elk lesion homogenate used as inoculum. Bacteroidies, Fusobacterium, and Clostridia were among the bacterial taxa overrepresented in infected samples as compared to negative control samples. In conclusion, there is a highly transmissible, infectious bacterial component to elk treponeme-associated hoof disease which includes several species of Treponema as well as other bacteria previously associated with digital dermatitis.

Camel milk modulates α-lactalbumin induced changes in the gut microbiota in a murine model of cow’s milk allergy

Camel milk has been noted to have medicinal properties treating allergies, diarrhea, microbial infection and Crohn's disease.The aim of this study is to identify and characterize the intestinal microbiota of BALB/c mice sensitized to α-lactalbumin (α-la) and fed with camel milk. For this, 30 females BALB/c mice aged between 4 and 6 weeks were divided into two groups. The first one designated as control group did not receive any treatment (n=10). The second group (n=20) was immunized intraperitoneally with α-la. On day 35 of sensitization protocol, mice of the second group were divided into two subgroups of 10 mice each. Animals of the first subgroup were sacrificed, whereas, mice of the second subgroup were fed camel milk for one week. In order to analyze the effect of camel milk on α-La-sensitized mice, two studies were carried out: a histological analysis of the jejunal tissues and microbiolo-gical study in the intestine and faeces of mice of different groups. Our results showed that drinking camel milk significantly reduced the alteration of in-testinal epithelium induced by α-la immunization as demonstrated by a signi-ficant increase of villus height (p<0.05). The microbiological results showed a very significant increase in enterobacteria and anaerobic bacteria (1 to 2 log ufc/g) in bacterial flora of mice immunized to α-la. However there was no significant difference in the level of enterobacteriaceae and anaerobic bacte-ria in the faeces of α-la-immunized mice treated with camel milk. In conclu-sion, Camel milk reduced the microscopic lesions caused by α-lasensitization and play an antibacterial role againstpathogenic bacteria in the intestinal mucosa of mice immunized to cow’s milk proteins especially α-la.

Exploring Yak (Bos grunniens) Rumen Bacterial and Fungal Communities from 5 Days after Birth to Adulthood

The gut microbial community of mammals, especially ruminants, plays an important role at different ages of the host. Ruminants have a unique compartment in their digestive tract; the rumen, comprising microorganisms that can effectively decompose plant fibers for the host to transform into milk and for growth and development, which is important for meat production. Colonization of rumen microorganisms is closely related to host developmental stage and affects host performance production. There is little information regarding initial colonization and subsequent changes of the rumen microbial population in wild grazing animals, from birth to adulthood. This study investigated the rumen bacterial and fungal populations of grazing yaks in five experimental groups, ranging from a few days after birth to adulthood using amplicon sequencing. Results indicated that rumen microbial communities of these yaks undergo a gradual change from 5 to 180 days after birth, with the bacterial and fungal diversity stabilizing at the age of 2 years. Additionally, Ruminococcus was detected in 5-day-old yak rumens, with a high percentage of Penicillium and other microbial species are important for normal rumen function detected in the adult rumen. The changes to the yak rumen microbial community after birth were reflected in the increased anaerobic fiber degradation group, and decreased aerobic and facultative anaerobic bacteria. Microbial diversity and abundance in the yak rumen increased with age. Rumen microbial composition of 6-month and 2-year-old yaks had obvious homogeneity. There were some differences in dominant rumen microorganisms among the different age groups. Further studies are required to confirm the functions of these differential and dominant microorganisms in each age group.

The role of the microbiota in the management of intensive care patients

The composition of the gut microbiota is highly dynamic and changes according to various conditions. The gut microbiota mainly includes difficult-to-cultivate anaerobic bacteria, hence knowledge about its composition has significantly arisen from culture-independent methods based on next-generation sequencing (NGS) such as 16S profiling and shotgun metagenomics. The gut microbiota of patients hospitalized in intensive care units (ICU) undergoes many alterations because of critical illness, antibiotics, and other ICU-specific medications. It is then characterized by lower richness and diversity, and dominated by opportunistic pathogens such as Clostridioides difficile and multidrug-resistant bacteria. These alterations are associated with an increased risk of infectious complications or death. Specifically, at the time of writing, it appears possible to identify distinct microbiota patterns associated with severity or infectivity in COVID-19 patients, paving the way for the potential use of dysbiosis markers to predict patient outcomes. Correcting the microbiota disturbances to avoid their consequences is now possible. Fecal microbiota transplantation is recommended in recurrent C. difficile infections and microbiota-protecting treatments such as antibiotic inactivators are currently being developed. The growing interest in the microbiota and microbiota-associated therapies suggests that the control of the dysbiosis could be a key factor in the management of critically ill patients. The present narrative review aims to provide a synthetic overview of microbiota, from healthy individuals to critically ill patients. After an introduction to the different techniques used for studying the microbiota, we review the determinants involved in the alteration of the microbiota in ICU patients and the latter’s consequences. Last, we assess the means to prevent or correct microbiota alteration.

Pulse Voltage Electrical Stimulation for Bacterial Inactivation and Wound Healing in Mice with Diabetes

Background: Treatment of wounds in diabetes often gets less than perfect healing. One of the reasons for the difficulty in treating wounds in diabetes is the growth of aerobic and anaerobic bacteria. This study aims to determine the pulse voltage and treatment time that can optimally inactivate bacteria, and their effect on wound healing in mice suffering from diabetes. Methods: The study used electrical stimulation with a direct voltage of 10 volts given a pulse voltage of 50-80 volts, a width of 50 µs, and the number of pulses of 65 per second. The research samples were Staphylococcus aureus (S. aureus) and Pseudo-monas aeruginosa (P. aeruginosa) bacteria that grew on beef and mice (Mus musculus) with diabetes. The treatment for S. aureus and P. aeruginosa bacteria was carried out using a pulse voltage of 50-80 volts for 5-15 min/day and repeated for 3 days. Meanwhile, treatment of mice wounds was carried out with a pulse voltage of 80 volts for 15 min/day and repeated for 7 days. Results: The results showed that treatment with a pulse voltage of 50-80 volts and a treatment time of 5-15 min significantly reduced the number of S. aureus and P. aeruginosa bacteria in beef (p£0.05). Treatment with a pulse voltage of 80 volts for 15 min made beef free from bacteria. Meanwhile, treatment with a pulse voltage of 80 volts for 15 min per day for seven days resulted in the wound state of three mice in the maturation phase and two mice in the proliferation phase on day 8 with an average wound area of 0.108 cm 2. Conclusion: The treatment with a pulse voltage of 80 volts for 15 min made the beef sterile, the mice wounds healed quickly, and the mice not stressed. The higher the blood glucose level, the slower the wound healing process.