Propolis in the control of bacterial bovine mastitis: a tool for the production of organic milk

Bovine mastitis is one of the main causes of economic damage in dairy farms. Therefore, the control and prevention of microorganisms involved in this disease, mainly Escherichia coli, Staphylococcus aureus, and Streptococcus agalactiae, are essential. One of the most important steps for the prevention of the disease is the use of antiseptic products before and after the milking process to avoid bacteria from infecting the udder of the animal. Currently, the most used antiseptic product in dairy farms is iodine-based, and organic dairy farms, which follow several strict regulations, including the use of natural products whenever possible, are often forced to adopt non-natural antiseptic products, such as iodine-based ones, because of the lack of natural alternatives. Propolis, a natural substance produced by honeybees, has been extensively studied for its various properties, one of which is antimicrobial activity. Therefore, a new natural antiseptic product containing 1% propolis in 10% hydroalcoholic solution for the pre-dipping, and 10% glycerol solution added with 0.2% citronella oil for the post-dipping was analyzed for its capacity to reduce bacteria in vivo in order to prevent bovine mastitis, allowing its use on organic dairy farms. A total of 128 samples were analyzed in terms of bacterial growth for Enterobacteriaceae and Staphylococcus spp. using the spreadplate technique. The reduction in the bacterial concentration after the application of the products was compared between two antiseptic solutions, an iodine-based solution as the control and a propolis-based one as the natural alternative. The results obtained show a similar efficiency for both products in terms of total bacterial reduction, indicating considerable antimicrobial activity against bacteria most commonly associated with bovine mastitis. Molecular analysis was carried out for the identification of Streptococcus agalactiae; the PCR results were negative for the presence of S. agalactiae in all samples, indicating that the animals most likely did not have any form of the disease. The efficiency of the natural antiseptic was satisfactory, indicating an important find facilitating organic milk production worldwide, showcasing a natural antiseptic solution with efficient antimicrobial activity.

Dietary Agaricus blazei Spent Substrate Improves Disease Resistance of Nile Tilapia (Oreochromis niloticus) against Streptococcus agalactiae In Vivo

This study evaluated the effects of the feeding of spent mushroom substrate from Agaricus blazei on Nile tilapia (Oreochromis niloticus). The safety of 0–1000 μg/mL A. blazei spent substrate water extract (ABSSE) was demonstrated in the primary hepatic and splenic macrophages and the THK cell line (a cell line with characteristics of melanomacrophages) using a cytotoxicity assay. Here, 10 μg/mL of crude ABSSE promoted the phagocytic activity of macrophages and THK cells. Stimulating ABSSE-primed THK cells with lipopolysaccharides or peptidoglycan resulted in higher expression levels of four cytokine genes (e.g., interleukinz (IL)-1β, IL-12b, IL-8 and tumor necrosis factor α (TNFα)) and one cytokine gene (TNFα), respectively. An in vitro bacterial growth inhibition assay demonstrated that ABSSE could inhibit the growth of Streptococcus agalactiae. In the first feeding trial, Nile tilapia were fed with experimental feed containing 0, 1, or 5% of A. blazei spent substrate (ABSS) for seven and fourteen days followed by bacterial challenge assay. The best result was obtained when Nile tilapia were continuously fed for seven days on a diet containing 1% ABSS, with the survival rate being higher than in groups with 0% and 5% ABSS after challenge with S. agalactiae. In the second trial, fish were fed diets supplemented with 0% or 1% ABSS for seven days, and then all the groups were given the control feed for several days prior to bacterial challenge in order to investigate the duration of the protective effect provided by ABSS. The results showed that the protective effects were sustained at day 7 after the feed was switched. Overall, spent mushroom substrate from A. blazei is a cost-effective feed additive for Nile tilapia that protects fish from S. agalactiae infection.

Streptococcus agalactiae infective endocarditis in Canada: a multicenter retrospective nested case control analysis

Background Infective endocarditis (IE) caused by Streptococcus agalactiae (GBS) is increasingly reported and associated with an aggressive course and high mortality rate. Existing literature on GBS IE is limited to case series; we compared the characteristics of patients with GBS IE to patients with GBS bacteremia without IE to identify risk factors for development of IE. Methods A nested case–control study in a cohort of adult patients with GBS bacteremia over a 18-year period was conducted across seven centres in three Canadian cities. A chart review identified patients with possible or definite IE (per Modified Duke Criteria) and patients with IE were matched to those without endocarditis in a 1:3 fashion. Multivariate analyses were completed using logistic regression. Results Of 520 patients with GBS bacteremia, 28 cases of possible or definite IE were identified (5.4%). 68% (19/28) met criteria for definite IE, surgery was performed in 29% (8/28), and the overall in-hospital mortality rate was 29% (8/28). Multivariate analysis demonstrated that IE was associated with injection drug use (OR = 19.6, 95% CI = 3.39–111.11, p = 0.001), prosthetic valve (OR = 11.5, 95% CI = 1.73–76.92, p = 0.011) and lack of identified source of bacteremia (OR = 3.81, 95% CI = 1.24–11.65, p = 0.019). Conclusions GBS bacteremia, especially amongst people who inject drugs, those with prosthetic valves, and those with no apparent source of infection, should increase clinical suspicion for IE.

VIRULENCE GENE PROFILING AND PATHOGENICITY OF Streptococcus agalactiae ISOLATED FROM TILAPIA, Oreochromis niloticus FARMS IN INDONESIA

Streptococcosis caused by Streptococcus agalactiae has become a major disease problem in tilapia culture in Indonesia. This study aimed to detect virulence genes of S. agalactiae during streptococcosis disease outbreaks in several tilapia farms in Indonesia and evaluate the correlation between biotype and virulence genes to bacterial virulence. The presence of virulence genes was determined in 10 strains of S. agalactiae isolated from farm-raised tilapia. Polymerase chain reaction (PCR) protocol was used to determine genes for cylE, hylB, lmb, bib A, PI-2b, fbs A, fbs B, gap, PI-1, and cfb in the template DNA. Pathogenicity test was carried out by intraperitoneal injection of 24 hour-cultured S. agalactiae to tilapia with 108 CFU/fish. Four isolates have seven of virulence genes (cylE, hylB, bibA, PI-2b, fbs A, fbs B, and gap genes), three isolates have six virulence genes (hylB, bib A, fbs A, fbs B, gap, cfb genes), one isolate has four virulence gene (hyl B, bib A, fbs, and cfb genes), and one isolate has one virulence gene (PI-2b gene). None of the isolates has lmb or PI-1 genes. Bacteria with more virulence genes showed higher pathogenicity post injection. Mortality of tilapia injected with b-hemolytic bacteria was 100% within the period of 14-19 hours, while non-hemolytic bacteria was 53.3%-86.6% on 14 days post-injection. Pathological changes associated with the infection by either isolate included melanosis, slow response, anorexia, ocular opacity, gasping, erratic, C-shape, and whirling. It can be concluded that S. agalactiae with more virulence genes show a higher level of pathogenicity. The presence of a virulent gene has the potential to be used as a basis for selecting candidate isolates and designing vaccine compositions as an effort to prevent streptococcosis infection in tilapia in Indonesia.

Experience in the diagnosis of group B Streptococcus infections in pregnant women and newborns in a perinatal center

Serogroup B streptococci (Streptococcus agalactiae) are one of the main etiological agents responsible for the occurrence of severe perinatal infections in both postpartum women and newborns. The experience of microbiological diagnostics of infections caused by streptococcus serogroup B (GBS) according to the data of the microbiological laboratory of the perinatal center is generalized. In the study of biomaterial from patients, the proportion of positive cultures of Streptococcus agalactiae was 2.2% in cervical samples, 8.8% in vaginal contents, 6.6%; 2.8% and 0.7% in amniotic fluid, placenta and urine, respectively. In 57% of cases, GBS was released at a concentration of more than 5 lg / ml and in 73% of cases as part of polymicrobial associations with other opportunistic microorganisms. In the biomaterial from newborns, GBS was found in 2.5% of positive findings in blood samples, 4.6% in tracheobronchial lavages and 2.7% in detachable skin of the armpit when taking material immediately after childbirth and 1, 1% and 0.7%, respectively, during examination in the second stage of nursing. 5 cases of GBS isolation in newborns ended in early neonatal mortality with definitive diagnoses of congenital pneumonia and IUI of newborns, while there was only partial coincidence of the results of microbiological studies of the genital tract of the mother and biomaterials from the newborn. Relatively frequent findings of GBS in newborns of the high-risk group in intensive care unit indicate intrauterine infection with this pathogen. The examination of smears from the cervical canal is not informative in relation toGBS infection in comparison with the examination of the vaginal contents and recto-vaginal smears. The results of the introduction of microbiological screening and its effectiveness in real practice to prevent the development of early and late forms of GBS infections in newborns require further analysis.