Major Causative Bacteria Research Articles

Contribution of collagen-binding protein Cnm of Streptococcus mutans to induced IgA nephropathy-like nephritis in rats

IgA nephropathy (IgAN), the most common primary glomerulonephritis, is considered an intractable disease with unknown pathogenic factors. In our previous study, Streptococcus mutans, the major causative bacteria of dental caries, which expresses Cnm, was related to the induction of IgAN-like nephritis. In the present study, the Cnm-positive S. mutans parental strain, a Cnm-defective isogenic mutant strain, its complementation strain, and recombinant Cnm (rCnm) protein were administered intravenously to Sprague Dawley rats, and the condition of their kidneys was evaluated focusing on the pathogenicity of Cnm. Rats treated with parental and complement bacterial strains and rCnm protein developed IgAN-like nephritis with mesangial proliferation and IgA and C3 mesangial deposition. Scanning immunoelectron microscopy revealed that rCnm was present in the electron-dense deposition area of the mesangial region in the rCnm protein group. These results demonstrated that the Cnm protein itself is an important factor in the induction of IgAN in rats.

Clinical features relating to pneumococcal colony phase variation in hospitalized adults with pneumonia.

Background. Streptococcus pneumoniae is a major causative bacteria of pneumonia and invasive pneumococcal disease (IPD); however, the mechanisms underlying its severity and invasion remain to be defined. Pneumococcal colonies exhibit opaque and transparent opacity phase variations, which have been associated with invasive infections and nasal colonization, respectively, in animal studies. This study evaluated the relationship between the opacity of pneumococcal colonies and the clinical presentation of pneumococcal pneumonia.Methods. This retrospective study included adult patients hospitalized with pneumococcal pneumonia between 2012 and 2019 at four tertiary medical institutions. Pneumococcal strains from lower respiratory tract specimens were determined for their serotypes and microscopic colony opacity, and the association between the opacity phase and the severity of pneumonia was evaluated. Serotypes 3 and 37 with mucoid colony phenotypes were excluded from the study because their colony morphologies were clearly different.Results. A total of 92 patients were included. Most patients were older adults (median age: 72 years) and males (67 %), and 59 % had community-acquired pneumonia. Of the 92 patients, 41 (45 %), 12 (13 %), and 39 (42 %) patients had opaque, transparent, and mixed variants in their pneumococcal colony, respectively. The opaque and non-opaque pneumococcal variants had no statistically significant difference in patient backgrounds. Although the pneumonia severity index score did not differ between the opaque and non-opaque groups, the rate of bacteremia was significantly higher in the opaque group than in the non-opaque group. Serotype distribution was similar between the groups.Conclusions. Opaque pneumococcal variants may cause pneumonia and invasive diseases in humans. This study could help elucidate IPD, and opacity assessment may serve as a predictor for IPD.

Antibiotic-Loaded Ultrahigh Molecular Weight Polyethylenes.

The occurrence of periprosthetic joint infections (PJI) after total joint replacement constitutes a great burden for the patients and the healthcare system. Antibiotic-loaded polymethylmethacrylate (PMMA) bone cement is often used in temporary spacers during antibiotic treatment. PMMA is not a load-bearing solution and needs to be replaced by a functional implant. Elution from the ultrahigh molecular weight polyethylene (UHMWPE) bearing surface for drug delivery can combine functionality with the release of clinically relevant doses of antibiotics. In this study, the feasibility of incorporating a range of antibiotics into UHMWPE is investigated. Drug stability is assessed by thermo-gravimetric analysis and nuclear magnetic resonance spectroscopy. Drug-loaded UHMWPEs are prepared by compression molding, using eight antibiotics at different loading. The predicted intra-articular concentrations of drugs eluted from UHMWPE are above minimum inhibitory concentration for at least 3 weeks against Staphylococci, which are the major causative bacteria for PJI. The antibacterial efficacy is confirmed for samples covering 2% of a representative knee implant in vitro over 72 h, showing that a small fraction of the implant surface loaded with antibiotics may be sufficient against Staphylococci.

Molecular characterization of Klebsiella pneumoniae associted with Thalassemia in Thi-Qar Governorate

Klebsiella pneumoniae is a gram-negative, aerobic, non-motile bacilli and is a common cause of a wide range of infections in humans, Klebsiella spp. as a major causative bacteria in Thalassemia patient. The present study aimed to shed light on the supposed role of bacterial infection in Thalassemia patients during the period of from August 2022 to December 2023 in Genetic Blood Diseases/Thi-Qar Governorate. Forty blood sample were collected from all patients and subjected to Conventional Polymerase Chain Reaction assay by using the Universal gene. Nine PCR product were selected and subjected to partial DNA sequencing for the 16S rRNA gene to follow up their possible relationship between them and what recorded globally in Gene bank. The results revealed that 9/40(25%) isolates were K. pneumoniae. PCR product of 16SrRNA registered in Gene bank under the official accession numbers of OQ928953.1,OQ929666.1,OQ928950.1,OQ929250.1,OQ927231.1,OQ928942.1,OQ927249.1,OQ927229.1 and OQ927253.1). The phylogenetic tree that was constructed by MEGA-10 software showed that there were different molecular relationships among the local K. pneumonia isolates with analogous ones around the world.

16S rRNA nanopore sequencing for rapid diagnosis of causative bacteria in bovine mastitis

The rapid identification of specific bacterial pathogens in bovine mastitis is crucial for appropriate antimicrobial treatment. Sequencing of 16S rRNA gene amplicons is a proven, useful strategy for diagnosing bacterial infections. In this study, the use of 16S rRNA analysis with nanopore sequencer for the rapid identification of causative bacteria in bovine mastitis, was evaluated. DNA was extracted from 122 milk samples from cattle with suspected mastitis based on clinical symptoms. 16S rRNA gene amplicon sequencing was conducted using a nanopore sequencer. The efficacy of bacterial identification was verified by comparison with conventional culture methods. Nanopore sequencing identified the causative bacteria with high accuracy within approximately 6 h from the time of sample collection. When the major causative bacteria of bovine mastitis (Escherichia coli, Streptcoccus uberis, Klebsiella pneumoniae, and Staphylococcus aureus) were detected by nanopore sequencing, 98.3% of the results were consistent with identification through conventional culturing methods. 16S rRNA gene analysis using a nanopore sequencer enabled the rapid and accurate identification of bacterial species in bovine mastitis.

Clinicopathological Characteristics of Acute Pyelonephritis with or without Renal Failure and Current Status of Antimicrobial Susceptibility

Acute pyelonephritis (APN) is the most common bacterial infection involving the upper urinary tract system, including the renal parenchyma and pelvis. Complications of APN include renal abscess, septic shock, and renal impairment, including AKI. At the same time, antibiotic resistance of uropathogens Resulted in unfavorable clinical responses in APN. The objective of the study was to evaluate the clinical characteristics of patients with APN and antimicrobial susceptibility of causative bacteria. It was a cross-sectional type of observational study which included 100 diagnosed patients of APN admitted into the department of nephrology, Rajshahi Medical College Hospital, Rajshahi, from January 2018 to December 2018. In both males and females, E. coli was the major causative bacteria (51.1% vs. 48.9%). Renal failure was present in 87% of patients, and among them, AKI was present in 81.6% and CKD in 18.4%). Infection with klebsiella was significantly more common among CKD patients as compared to AKI (p<0.05). Commonly used antibiotic ceftriaxone was found significantly resistant in the case of E. coli (p<0.01) and klebsiella (p<0.05). In the majority of cases (>50%), E. coli was susceptible to nitrofurantoin, amikacin, imipenem, meropenem, and piperacillin-tazobactam. Resistance to antibiotics may complicate the condition. Antibiotic resistance to several commonly used antibiotics TAJ 2021; 34: No-2: 32-42

Risk factors for canine magnesium ammonium phosphate urolithiasis associated with bacterial infection.

BackgroundWith limited information available, the association among urinary tract infections, urease-producing bacteria and the presence of magnesium ammonium phosphate (MAP) urolithiasis in canines in Thailand requires more study.ObjectivesThis study aimed to investigate the association between demographic characteristics of canines and the presence of MAP urolithiasis in canines, and to evaluate antimicrobial susceptibility patterns of bacteria isolated from canine uroliths.MethodsA total of 56 canines admitted for treatment with surgical removal of uroliths were recruited. Demographic characteristics and clinical chemistry data were recorded. Bacteria isolated from the removed uroliths were identified. Chemical compositions of the uroliths were analyzed by Fourier transform infrared spectrometer. Potential risk factors were determined with univariable and multivariable logistic regression analyses.ResultsOf 56 canine urolithiasis, bacteria were isolated from uroliths of 38 canines (27 MAP and 11 non-MAP) but not from uroliths of 18 canines (5 MAP and 13 non-MAP). The most common bacteria found in nidus of MAP uroliths was Staphylococcus pseudintermedius (approximately 51%). An antimicrobial resistance was frequently found in Staphylococci isolates (42.86%). Multivariate logistic regression analysis showed that the predictors of MAP urolith in canine urolithiasis were being female (p = 0.044; adjusted odds ratio [OR], 10.22; 95% confidence interval [CI], 1.06–98.24) and the positive urolith culture (p = 0.012; adjusted OR, 8.60; 95% CI, 1.60–46.30).ConclusionsOur results indicate that S. pseudintermedius (a urease-producing bacterium) is the major causative bacteria of MAP uroliths. A positive urolith culture and being female are risk factors of MAP urolithiasis in canines.

Comparative Study of the Antimicrobial Activity of Clove Oil and Clove Extract on Oral Pathogens

Objective The main objective of the present study was to do the comparative study of clove oil and clove extract on the oral micro-biota causing dental caries and also to assess the antifungal activity. Materials and Methods The antimicrobial activity of clove oil and clove extract was assessed against Halobacterium sp., Lactobacillus sp., Pseudomonas sp., Micrococcus sp. and Streptococcus mutans (major causative bacteria of dental plaque) by the paper disc diffusion method. For each extract three replicate trials were conducted against each organism. The antifungal activity of clove oil and extract was also assessed against seven fungal species (Aspergillus niger, A. fumigatus, Aspergillus sp., Alternaria sp., Rhizomucor sp., Rhizopus sp. and Penicillium sp.) by agar disc diffusion method. Results Both clove oil and clove extract was found to exhibit broad spectrum of antibacterial activity inhibiting all the ten test bacterial species involved in dental caries. Clove oil produced maximum inhibition zone of diameter (IZD) against themajor causative bacteria of dental plaque as compared to clove extract, thereby, showing that clove oil possesses strong bactericidal activity against oral pathogens. The highest inhibition zone of diameter was observed by clove oil as compared to clove extract against the test fungal species Conclusion The clove oil has the potential to be used as a natural antibacterial agent for oral pathogens.

Effect of CARD9 Deficiency on Neutrophil-Mediated Host Defense against Pulmonary Infection with Streptococcus pneumoniae.

Streptococcus pneumoniae is a major causative bacterium of community-acquired pneumonia. Dendritic cell-associated C-type lectin-2 (dectin-2), one of the C-type lectin receptors (CLRs), was previously reported to play a pivotal role in host defense against pneumococcal infection through regulating phagocytosis by neutrophils while not being involved in neutrophil accumulation. In the present study, to elucidate the possible contribution of other CLRs to neutrophil accumulation, we examined the role of caspase recruitment domain-containing protein 9 (CARD9), a common adaptor molecule for signal transduction triggered by CLRs, in neutrophilic inflammatory response against pneumococcal infection. Wild-type (WT), CARD9 knockout (KO), and dectin-2 KO mice were infected intratracheally with pneumococcus, and the infected lungs were histopathologically analyzed to assess neutrophil accumulation at 24 h postinfection. Bronchoalveolar lavage fluids (BALFs) were collected at the same time point to count the neutrophils and assess the production of inflammatory cytokines and chemokines. Neutrophil accumulation was significantly decreased in CARD9 KO mice, but not in dectin-2 KO mice. Tumor necrosis factor alpha (TNF-α), keratinocyte-derived chemokine (KC), and macrophage inflammatory protein-2 (MIP-2) production in BALFs were also attenuated in CARD9 KO mice, but not in dectin-2 KO mice. Production of TNF-α and KC by alveolar macrophages stimulated with pneumococcal culture supernatants was significantly attenuated in CARD9 KO mice, but not in dectin-2 KO mice, compared to that in each group's respective control mice. In addition, pneumococcus-infected CARD9 KO mice showed larger bacterial burdens in the lungs than did WT mice. These data indicate that CARD9 is required for neutrophil migration after pneumococcal infection, as well as inflammatory cytokine and chemokine production by alveolar macrophages, and suggest that a CLR distinct from dectin-2 may be involved in this response.

Analysis of Interaction Between Porphyromonas gingivalis and Endothelial Cells In Vitro.

Chronic periodontitis is the most common periodontitis observed in adults. Recently, its association with systemic diseases such as ischemic heart-brain disease and diabetes has been pointed out. Porphyromonas gingivalis, a major causative bacterium of chronic periodontitis, has properties of adhering to blood vessels and inducing inflammation, and those properties are involved in the induction of vascular inflammation and promotion of atherosclerosis. Therefore, analysis of the interaction of P. gingivalis with vascular endothelial cells will contribute to an understanding of the link between periodontitis and vascular lesions.

The involvement of C5a in the progression of experimental arthritis with Porphyromonas gingivalis infection in SKG mice

BackgroundEpidemiological evidence to suggest that periodontal disease (PD) is involved in the progression of rheumatoid arthritis (RA) is increasing. The complement system plays a critical role in immune responses. C5a has been implicated in chronic inflammatory diseases, including PD and RA. Porphyromonas gingivalis is the major causative bacteria of PD and can produce C5a. Therefore, it is hypothesized that P. gingivalis infection is involved in the progression of RA by elevating C5a levels. In the present study, P. gingivalis–infected RA model mice were established to investigate the involvement of C5a.MethodsSKG mice orally infected with P. gingivalis were immunized with intraperitoneal injection of laminarin (LA) to induce arthritis. Arthritis development was assessed by arthritis score (AS), bone destruction on the talus, histology, and serum markers of RA. In order to investigate the effects of serum C5a on bone destruction, osteoclast differentiation of bone marrow mononuclear cells was examined by using serum samples from each group of mice. The relationship between C5a levels and antibody titers to periodontal pathogens in patients with RA was investigated by enzyme-linked immunosorbent assay.ResultsP. gingivalis oral infection increased AS, infiltration of inflammatory cells, bone destruction on the talus, and serum markers of RA in mice immunized with LA. The addition of serum from LA-injected mice with the P. gingivalis oral infection promoted osteoclast differentiation, and the addition of a neutralization antibody against C5a suppressed osteoclast differentiation. C5a levels of serum in RA patients with positive P. gingivalis antibody were elevated compared with those in RA patients with negative P. gingivalis antibody.ConclusionsThese results suggest that P. gingivalis infection enhances the progression of RA via C5a.

Antimicrobial Effect of Polyphenon 60 against <i>Streptococcus mutans</i> and <i>Streptococcus sobrinus</i>

Polyphenon 60 refers to the mixture of catechins present in green tea. The aim of this study was to investigate the antimicrobial activities of polyphenon 60 against 4 strains of Streptococcus mutans and 2 strains of Streptococcus sorbrinus, which are the major causative bacteria of dental caries. The minimum bactericidal concentration (MBC) values of polyphenon 60 for S. mutans and S. sobrinus were determined and the effect of biofilm formation inhibition of that was evaluated. The MBC value of polyphenon 60 against the bacterial strains was 2.5 mg/ml except for one particular strain, S. mutans KCOM 1128 for which the value was 1.25 mg/ml. The results of biofilm formation inhibition assay revealed that polyphenon 60 inhibited biofilm formation more than 90% at a concentration of 2.5 mg/ml. It was apparent that polyphenon exhibited biofilm formation inhibition activity along with bactericidal effect against S. mutans and S. sobrinus. Therefore, it is proposed that polyphenon 60 as one of the components of bactericidal agents could be useful in developing oral hygiene products, toothpaste or gargling solution.

Clinical responses in cows vaccinated with a developed prototype killed Staphylococcus aureus mastitis vaccine

Mastitis is an inflammatory condition of the udder that occurs as a result of the release of leucocytes into the udder in a response to bacterial invasion. The major causes of mastitis are an array of gram positive and negative bacteria, however, algae, virus, fungi, mechanical or thermal injury to the gland have also been identified as possible causes. Mastitis vaccines are yet to be developed using Malaysian local isolate of bacteria. The objective of the present experimental trial was to develop a monovalent vaccine against mastitis using S. aureus of Malaysian isolate and to evaluate the clinical responses such as temperature, respiratory rates and heart rates in vaccinated cows. S. aureus is a major causative bacteria in clinical and subclinical types of mastitis in cows. Four concentrations of the bacterin (106, 107, 108 and 109 cfu/ml of the local isolate of S. aureus) were prepared using Aluminium potassium sulfate adjuvant. Thirty cows were grouped into four treatment groups (B, C, D and E) with a fifth group as control (A). These groups were vaccinated intramuscularly(IM) with the prepared monovalent vaccine and its influence on the vital signs were intermittently measured. The mean of rectal temperature was significantly different (p˂ 0.05) at 0hr Post Vaccination [1]" in groups D and E (39.5 ± 0.15 °C and 39.4 ± 0.15 °C respectively) and at 3 h PV in groups C, D and E (39.8 ± 0.14 °C, 39.9 ± 0.14 °C and 40.3 ± 0.14 °C respectively) compared to the control group. This indicated a sharp increased rectal temperatures between 0hr and 3 h PV in groups C, D and E which later declined at 24 h PV. The mean of rectal temperature of group E was significantly different (p˂ 0.05) at weeks 1 and 2 PV (39.87 ± 0.19 °C and 39.80 ± 0.18 °C respectively) compared to the control group. The mean of heart rate was significantly different (p˂ 0.05) at week 1 PV in groups D and E (83.0 ± 3.8 beats/minute and 80.0 ± 3.8 °C respectively) compared to control. A trending decrease was however observed in heart rates of group E from weeks through 4 PV and in group D from weeks 1 through 3 PV. The mean of respiratory rates was significantly different (p˂ 0.05) at week 3 PV in group B and D (31.0 ± 1.2 breaths/minute and 28.0 ± 1.2 breaths/minute) compared to control. In conclusion, this study highlights responses of these vital signs due to vaccination against S. aureus causing mastitis in cows. To the best of our knowledge the findings of this study adds value to the shallow literature on vital signs alterations in cows vaccinated against mastitis as elevated levels of temperature and heart rates of group D and E indicated obvious response.

Prevalence and types of bacterial infections of the upper respiratory tract at a tertiary care hospital in the City of Tripoli

Abstract Aim: The study aimed to determine the bacterial etiology of upper tract respiratory infection in Abu-Sitta Hospital, Tripoli, Libya. Subjects and Methods: A total of 470 sputum specimens and 60 throat swabs were collected over a period of 1 year (From January 2014 to December 2014) from patients presented with clinical signs of upper respiratory tract infection at Abu-Sitta Hospital. Enrolled patients were sorted as inpatients or outpatients and by gender. Data were entered and analyzed using SPSS version 22.0. Variables were expressed as percentages. Differences in age and gender were analyzed using Chi-square test. Results: Of the total 530 screened samples, 80.5% were culture positive, where bacterial pathogens were detected in 83.7% of sputum specimens and in 56.5% of throat swabs. Streptococcus pneumoniae was the most prevalent (48%), followed by Pseudomonas aeruginosa (23%), Staphylococcus aureus (13%), Enterobacter (8%), Citrobacter freundil (5%), and latest with Klebsiella (3%). Conclusions: The spectrum of pathogenic bacterium causing upper respiratory infection in Abu-Sitta Hospital is considerably wide, with S. pneumoniae and P. aeruginosa being the major causative bacteria.

Bactericidal activity and post-antibiotic effect of ozenoxacin against Propionibacterium acnes.

Ozenoxacin, a novel non-fluorinated topical quinolone, is used for the treatment of acne vulgaris in Japan. We investigated bactericidal activity and post-antibiotic effect (PAE) of ozenoxacin against Propionibacterium acnes, a major causative bacterium of acne vulgaris. The minimum inhibitory concentrations (MICs) of ozenoxacin against 3 levofloxacin-susceptible strains (MIC of levofloxacin; ≤4μg/mL) and 3 levofloxacin-resistant strains (MIC of levofloxacin; ≥8μg/mL) ranged from 0.03 to 0.06μg/mL and from 0.25 to 0.5μg/mL, respectively. These MICs of ozenoxacin were almost the same or lower than nadifloxacin and clindamycin. The minimum bactericidal concentrations (MBCs) of ozenoxacin against the levofloxacin-susceptible and -resistant strains were from 0.06 to 8μg/mL and from 0.5 to 4μg/mL, respectively. These MBCs were lower than those of nadifloxacin and clindamycin. In time-kill assay, ozenoxacin at 1/4, 1 and 4 times the respective MIC against both levofloxacin-susceptible and -resistant strains showed a concentration-dependent bactericidal activity. Ozenoxacin at 4 times the MICs against the levofloxacin-susceptible strains showed more potent and more rapid onset of bactericidal activity compared to nadifloxacin and clindamycin at 4 times the respective MICs. The PAEs of ozenoxacin at 4 times the MICs against the levofloxacin-susceptible strains were from 3.3 to 17.1h, which were almost the same or longer than nadifloxacin and clindamycin. In contrast, the PAEs were hardly induced by any antimicrobial agents against the levofloxacin-resistant strains. The present findings suggest that ozenoxacin has a potent bactericidal activity against both levofloxacin-susceptible and -resistant P.acnes, and a long-lasting PAE against levofloxacin-susceptible P.acnes.

MP11-10 CLINICAL PHARMACOKINETICS OF BETA-LACTAM ANTIBIOTICS IN PROSTATE TISSUE, AND DOSING CONSIDERATIONS FOR PROSTATITIS BASED ON SITE-SPECIFIC PHARMACODYNAMICS

INTRODUCTION AND OBJECTIVES: Carbapenems (doripenem and meropenem) are a therapeutic option for bacterial prostatitis and antibacterial prophylaxis in prostatic surgery, especially in patients who are intolerant or resistant to quinolones. However, the clinical pharmacokinetics (PK) of the two carbapenems in prostate tissue and attainment of their pharmacodynamic (PD) targets at site of action had been unclear. This study thus examined, for the first time, the clinical PK of doripenem and meropenem in prostate tissue, and estimated their PD target attainment at this site. METHODS: Doripenem (0.25 g or 0.5 g) or meropenem (0.25 g or 0.5 g) was intravenously administered to 101 patients with benign prostatic hypertrophy prior to TURP. Blood samples and prostate tissue samples were collected 0.5, 1, 1.5, 2, 3, 4 and 5 h after starting a 0.5-h infusion. Drug concentrations in plasma and prostate tissue were measured using high-performance liquid chromatography, analyzed using a three-compartment population pharmacokinetic model, and used to estimate the probability of attaining a bactericidal target (40% of the time above the minimum inhibitory concentration [MIC] for bacteria). RESULTS: These carbapenems penetrated similarly into prostate tissue, independently of the dose, with mean prostate tissue/ plasma ratios of 0.166e0.173 (maximum drug concentration) and 0.177e0.187 (area under drug concentration-time curve). Despite this relatively low penetration by doripenem and meropenem, their usual regimens of 0.25 g three times daily and 0.5 g twice daily (0.5-h infusions) achieved a favorable target-attainment probability value of 90.8e95.9%, in prostate tissue, against clinical isolate populations of Escherichia coli and Klebsiella species (the two major causative bacteria in prostatitis). However, Pseudomonas aeruginosa isolate population needed 0.5 g three times daily for probability values of 55.9% for doripenem and 52.3% for meropenem. The prostatic pharmacodynamic-based breakpoint MIC (the highest MIC at which the targetattainment probability in prostate tissue was more than 90%) was 0.063 mg/L for 0.25 g three times daily and 0.125 mg/L for 0.5 g three times daily, for both drugs. CONCLUSIONS: These results define clinical pharmacokinetics of doripenem and meropenem in prostate tissue, while also rationalizing and optimizing their dosing regimens for prostatitis on the basis of site-specific pharmacodynamic target attainment.

Effect of maternal use of chewing gums containing xylitol on transmission of mutans streptococci in children: a meta-analysis of randomized controlled trials.

Mutans streptococci (MS) are the major causative bacteria involved in human dental decay. Habitual consumption of xylitol has been proved to reduce MS levels in saliva and plaque. To evaluate the effect of the maternal use of xylitol gum on MS reduction in infants. A structured literature review and meta-analysis. A random effects model was used to assess the relative risks of the incidence of MS in the saliva or plaque of children who were 6, 9, 12, 18, and 24 months old. We reviewed 11 RCTs derived from 5 research teams that included 601 mothers. Our results indicated that the incidence of MS in the saliva or plaque of the infants was significantly reduced in the xylitol group (risk ratio: 0.54; 95% confidence interval: 0.39-0.73, at 12-18 months) and (risk ratio: 0.56; 95% confidence interval: 0.40-0.79, at 36 months) compared with the control groups. The long-term effect of maternal xylitol gum exposure on their children's dental caries was controversial. Habitual xylitol consumption by mothers with high MS levels was associated with a significant reduction in the mother-child transmission of salivary MS.

Antimicrobial Effects of Oleanolic Acid, Ursolic Acid, and Sophoraflavanone G against Enterococcus faecalis and Propionibacterium acnes

The aim of this study was to investigate antimicrobial effect of oleanolic acid (OA), ursolic acid (UA), and sophoraflavanone G against Enterococcus faecalis and Propionibacterium acnes, which are the major causative bacteria of endodontic infections. The antimicrobial activity was evaluated by the minimal inhibitory concentration (MIC). The data showed that the OA, UA, and sophoraflavanone G had antimicrobial effect on all the strains use in the study with 16-64 µg/ml, 8-64 µg/ml, and 1-8 µg/ml of MIC values, respectively. These results indicate that OA, UA, and sophoraflavanone G could be useful in the development of antiseptic solution for washing the root canal in endodontic treatments.

Antimicrobial Activity of Oleanolic Acid, Ursolic Acid, and Sophoraflavanone G against Periodontopathogens

In general, oleanolic acid (OA) and ursolic acid (UA) have antimicrobial effect against Gram-positive bacteria but not Gram-negative bacteria whereas sophoraflavanone G has antimicrobial activity against both bacterial types. However, the antimicrobial effects of OA, UA, and sophoraflavanone G against periodontopathogens have not been studied to any great extent. The aim of this study was to investigate antimicrobial effect of OA, UA, and sophoraflavanone G against 15 strains (5 species) of oral Gram-negative bacteria, which are the major causative bacteria of periodontal disease. The antimicrobial activity was evaluated by minimal inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) determinations. OA and UA showed antimicrobial effects against all of the Porphyromonas gingivalis strains tested and also Prevotella intermedia ATCC 25611T. Interestingly, P. intermedia ATCC 49046 showed greater resistance to OA and UA than P. intermedia ATCC 25611T. In contrast, sophoraflavanone G had antimicrobial activity against all strains, with MIC and MBC values below 32 μg/ml, except Aggregatibacter actinomycetemcomitans. These results indicate that sophoraflavanone G may have potential for use in future oral hygiene products such as dentifrices and gargling solution to prevent periodontitis.

Bovine mastitis prevalence and associated risk factors in dairy cows in Nyagatare District, Rwanda

In response to farmer requests after milk from their herds was rejected by processors due to poor quality, we conducted a study to investigate the prevalence of subclinical mastitis in dairy herds in the Nyagatare district of the Eastern province of Rwanda. The major causative bacteria were investigated and conclusions of the types of mastitis and risk factors thereof were assessed.