Proportion Of Streptococci Research Articles

Sputum microbiota and inflammatory subtypes in asthma, COPD, and its overlap

BackgroundAirway microbiota in asthma-COPD overlap (ACO) remains unknown. ObjectiveThis study with ACO-enriched population aimed to clarify airway microbiota in ACO and in mixed granulocytic inflammation, often detected in ACO and chronic airway diseases. MethodsThis is an observational cross-sectional study. Patients with asthma with airflow limitation, ACO and COPD were enrolled. Blood tests, pulmonary function, exhaled nitric oxide and sputum tests were conducted. Sputum microbiota was evaluated using the 16S rRNA gene sequencing technique. ResultsA total of 112 patients (13 asthma, 67 ACO, 32 COPD) were examined. There were no significant differences in α-diversity among the three diseases. The relative abundances of phylum Bacteroidetes, class Bacteroidia, and genus Porphyromonas were associated with decreased eosinophilic inflammation, and were significantly lower in ACO than in COPD. In a comparison of sputum inflammatory subtypes, the proportion of Haemophilus was numerically highest in the mixed granulocytic subtype, followed by the neutrophilic subtype. Likewise, the proportion of Haemophilus was the highest in the intermediate-high (2%–8%) sputum eosinophil group and lowest in the severe (8%≤) eosinophil group. Clinically, Haemophilus proportion was associated with sputum symptoms. Finally, the proportion of Streptococcus was associated with higher blood eosinophil counts and severest airflow limitation. ConclusionBacteroidia and Porphyromonas abundances in sputum are associated with the eosinophil-low phenotype, and ACO may be characterised by a decrease in these taxa. A mild elevation of sputum eosinophil does not preclude the presence of Haemophilus, which should be noted in the management of obstructive airway diseases.

Characteristics of antibiotic resistance of infectious pathogens in the wounded

ABSTRACT. This study examines the etiological structure and antibiotic resistance features of pathogens causing infectious complications in wounded patients receiving specialized medical care are considered. A total of 3845 clinical isolates were analyzed from wounded individuals admitted t o a multidisciplinary hospital for treatment. The analysis revealed that polyresistant pathogens, namely, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii were predominant among the isolated microorganisms. The prevalence of Acinetobacter baumannii varied based on the type of clinical material, with higher rates observed in wounds and respiratory, and urinary tract discharges. The polyresistant clinical isolates of Acinetobacter baumannii were sensitive to tigecycline and polymyxin, while Klebsiella pneumoniae and Pseudomonas aeruginosa were sensitive to polymyxin only. A comparison of the 2022 data with a previous study conducted in 2020 on wound discharges revealed a significant shift in the spectrum of pathogens causing wound infections. This shift involved an increase in the proportion of Acinetobacter spp., Bacillus spp., Enterococcus spp., Pseudomonas aeruginosa, and Klebsiella pneumoniae, as well as a decrease in the proportion of certain gram-negative bacteria, including Proteus spp. and Escherichia coli. Additionally, a notable five-fold reduction in the proportion of Streptococcus spp. and Staphylococcus aureus was observed. It is likely that early empirical therapy for combat wounds effectively prevents the development of wound infections associated with these pathogens. Bloodstream infections were primarily caused by coagulase-negative staphylococci (34.5%) and Klebsiella pneumoniae (27.8%). Notably, 80% of Staphylococcus spp. isolates were methicillin-resistant. The prolonged course of infectious complications associated with polyresistant strains and the challenges in selecting appropriate antibacterial therapy may contribute to the circulation of antibiotic-resistant nosocomial strains within the hospital environment. Therefore, it is crucial to increase the vigilance of the epidemiological service in addressing the high frequency of polyresistant pathogens to implement timely antiepidemic measures. Overall, these findings indicate the involvement of polyresistant gram-negative bacteria in the development of infectious complications during the inpatient treatment of wounded individuals.

Conjunctival sac flora and drug susceptibility analysis in normal children in East China

PurposeTo investigate the distribution characteristics of conjunctival sac flora and assess the susceptibility of commonly used topical antimicrobial agents in normal children under the age of 18 in East China.MethodsIn 2019, a study was conducted at Qingdao Eye Hospital of Shandong First Medical University to analyze the microorganism cultures of conjunctival sac in 1258 normal children (2516 eyes; average age, 6.21 ± 3.78 years) in East China. Exclusion criteria included children with ocular surface diseases and those who had used any topical antimicrobial agents recently. The microorganism species in the conjunctival sac were analyzed using the M-38A protocol (microdilution method; investigators read the minimum inhibitory concentration [MIC] values) by the Clinical and Laboratory Standards Institute to determine drug susceptibility.ResultsThe incidence of conjunctival sac microorganism in children was 32.87% (827/2516), a total of 541 cases (male 293, female 248). Children with conjunctival sac flora in a single eye were 255 and in both eyes were 286 (no statistical difference, P > 0.05). The concordance rate of children with binocular conjunctival sac flora was 32.16% (174/541; male 84, female 90). A total of 42 species of bacteria were detected. Children with Gram-positive cocci accounted for the highest proportion, 91.54% (757/827). The top three bacteria with the highest detection rates were Staphylococcus epidermidis (S. epidermidis; 52.12%), Streptococcus (12.09%), and Staphylococcus aureus (S. aureus; 10.76%). Streptococcus mitis (5.20%) accounted for the highest proportion of Streptococcus.S. epidermidis had the highest proportion in all age groups and was positively correlated with age (r = 0.89, P = 0.03). Before six years of age, the streptococcal proportion(mainly S. mitis) was greater than that of Staphylococcus aureus. The drug susceptibility analysis showed that S. epidermidis was most sensitive to gatifloxacin (98.61%), while it had the highest resistance rate to erythrocin (87.94%). S. aureus had the highest susceptibility to moxifloxacin (100%). Streptococcus was most sensitive to moxifloxacin (96.97%) and had the highest resistance rate to tobramycin (92.93%).ConclusionsConjunctival sac flora in children was dominated by Gram-positive cocci, mainly S. epidermidis, S. aureus, and Streptococcus. S. epidermidis increased with age; the proportion of Streptococcus was higher than S. aureus among children aged 0–6 years. The typical conjunctiva sac flora was generally sensitive to quinolones, such as moxifloxacin and gatifloxacin; Streptococcus displayed high resistance to tobramycin antibiotics; and the female children had higher resistance to tobramycin than the male children.

Orofacial Infections seen at A Specialist Dental Centre - A retrospective analysis of causative microbes and their antibiotic sensitivities over 6 years

ObjectiveWith increasing incidence of resistant microorganisms, it is beneficial to consider whether there has been a shift in spectrum and resistance profiles of microbes implicated in orofacial infections. This will help guide empirical antimicrobial choice in the treatment of such infections. The main objectives of this study were to investigate any change in trends of causative microbes associated with orofacial infections and their antibiotic sensitivity over the past 6 years and trends in prescription of empirical antibiotics in a specialist dental centre in Singapore. MethodsThis retrospective study was performed on outpatients at the National Dental Centre Singapore (NDCS) with orofacial infections from 1st Jan 2012 to 31st Oct 2017, requiring biological samples to be taken for culture and sensitivity (C&S) testing. ResultsThere was a statistically significant increasing trend in the proportion of Streptococcus spp. cultured from orofacial infections (p = 0.04). Over 6 years, 100 % of aerobes tested against Co-amoxiclav were deemed sensitive. ConclusionBeta lactams appear to have good coverage against most microbes implicated in orofacial infections, especially Co-Amoxiclav, and would be a good first-line empiric antibiotic for orofacial infections in the absence of beta-lactam allergy.

Impacts of Fructose on Intestinal Barrier Function, Inflammation and Microbiota in a Piglet Model.

The metabolic disorder caused by excessive fructose intake was reported extensively and often accompanied by intestinal barrier dysfunction. And the rising dietary fructose was consumed at an early age of human. However, related researches were almost conducted in rodent models, while in the anatomy and physiology of gastrointestinal tract, pig is more similar to human beings than rodents. Hence, weaned piglets were chosen as the model animals in our study to investigate the fructose’s impacts on intestinal tight junction, inflammation response and microbiota structure of piglets. Herein, growth performance, inflammatory response, oxidation resistance and ileal and colonic microbiota of piglet were detected after 35-day fructose supplementation. Our results showed decreased tight junction gene expressions in piglets after fructose addition, with no obvious changes in the growth performance, antioxidant resistance and inflammatory response. Moreover, fructose supplementation differently modified the microbiota structures in ileum and colon. In ileum, the proportions of Streptococcus and Faecalibacterium were higher in Fru group (fructose supplementation). In colon, the proportions of Blautia and Clostridium sensu stricto 1 were higher in Fru group. All the results suggested that tight junction dysfunction might be an earlier fructose-induced event than inflammatory response and oxidant stress and that altered microbes in ileum and colon might be the potential candidates to alleviate fructose-induced intestinal permeability alteration.

Association of exacerbation phenotype with the sputum microbiome in chronic obstructive pulmonary disease patients during the clinically stable state

BackgroundChronic obstructive pulmonary disease (COPD) is a progressive, life-threatening lung disease with increasing prevalence and incidence worldwide. Increasing evidence suggests that lung microbiomes might play a physiological role in acute exacerbations of COPD. The objective of this study was to characterize the association of the microbiota and exacerbation risk or airflow limitation in stable COPD patients.MethodsThe sputum microbiota from 78 COPD outpatients during periods of clinical stability was investigated using 16S rRNA V3-V4 amplicon sequencing. The microbiome profiles were compared between patients with different risks of exacerbation, i.e., the low risk exacerbator (LRE) or high risk exacerbator (HRE) groups, and with different airflow limitation severity, i.e., mild to moderate (FEV1 ≥ 50; PFT I) or severe to very severe (FEV1 < 50; PFT II).ResultsThe bacterial diversity (Chao1 and observed OTUs) was significantly decreased in the HRE group compared to that in the LRE group. The top 3 dominant phyla in sputum were Firmicutes, Actinobacteria, and Proteobacteria, which were similar in the HRE and LRE groups. At the genus level, compared to that in the LRE group (41.24%), the proportion of Streptococcus was slightly decreased in the HRE group (28.68%) (p = 0.007). However, the bacterial diversity and the proportion of dominant bacteria at the phylum and genus levels were similar between the PFT I and PFT II groups. Furthermore, the relative abundances of Gemella morbillorum, Prevotella histicola, and Streptococcus gordonii were decreased in the HRE group compared to those in the LRE group according to linear discriminant analysis effect size (LEfSe). Microbiome network analysis suggested altered bacterial cooperative regulation in different exacerbation phenotypes. The proportions of Proteobacteria and Neisseria were negatively correlated with the FEV1/FVC value. According to functional prediction of sputum bacterial communities through Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) analysis, genes involved in lipopolysaccharide biosynthesis and energy metabolism were enriched in the HRE group.ConclusionThe present study revealed that the sputum microbiome changed in COPD patients with different risks of exacerbation. Additionally, the bacterial cooperative networks were altered in the HRE patients and may contribute to disease exacerbation. Our results provide evidence that sputum microbiome community dysbiosis is associated with different COPD phenotypes, and we hope that by understanding the lung microbiome, a potentially modifiable clinical factor, further targets for improved COPD therapies during the clinically stable state may be elucidated.

The Composition and Predictive Function of the Fecal Microbiota Differ Between Young and Adult Donkeys.

The community of microorganisms inhabiting the gastrointestinal tract of monogastric herbivores played critical roles in the absorption of nutrients and keeping the host healthy. However, its establishment at different age groups has not been quantitatively and functionally examined. The knowledge of microbial colonization and its function in the intestinal tract of different-age donkeys is still limited. By applying the V3–V4 region of the bacterial 16S rRNA gene and functional prediction on fecal samples from different-age donkeys, we characterized the gut microbiota during the different age groups. In contrast to the adult donkeys, the gut microbiota diversity and richness of the young donkeys showed significantly less resemblance. The microbial data showed that diversity and richness increased with age, but a highly individual variation of microbial composition was observed at month 1. Principal coordinate analysis (PCoA) revealed a significant difference across five time points in the feces. The abundance of Bacteroides, Lactobacillus, and Odoribacter tended to decrease, while the proportion of Streptococcus was significantly increased with age. For functional prediction, the relative abundance of pathways had a significant difference in the feces across different age groups, for example, Terpenoids and Polyketides and Folding, Sorting, and Degradation (P < 0.05 or P < 0.01). The analysis of beta diversity (PCoA and LEfSe) and microbial functions predicted with PICRUSt (NSTIs) clearly divided the donkeys into foals (≤3 months old) and adults (≥7 months old). Microbial community composition and structure had distinctive features at each age group, in accordance with functional stability of the microbiota. Our findings established a framework for understanding the composition and function of the fecal microbiota to differ between young and adult donkeys.

Influence of Probiotics on the Salivary Microflora Oral Streptococci and Their Integration into Oral Biofilm.

Probiotics’ ability to integrate into dental biofilms is not yet clarified. The aim of this trial was to detect probiotic bacteria from probiotic products in dental biofilm and saliva during and after intake. In this parallel, randomized clinical trial, 39 subjects wore customized appliances to build up intra-oral biofilms (72-h periods). The trial was divided into screening (S) to determine baseline biofilm flora, intervention (I), and wash out (WO). During I (28 days), subjects consumed a product containing (a) Enterococcus faecalis (b) Lactobacillus casei, or (c) Lactobacillus rhamnosus GG. Probiotic bacteria and Streptococci spp. were detected in the biofilms and saliva of the 35 subjects that were included in the analysis. During I and WO, the ratio of probiotics in the biofilm was very low compared to total bacterial load, while saliva had slightly but not significantly higher values. No significant changes of probiotic bacteria (p > 0.05) were found at any visit during I or WO. The proportion of streptococci was significantly reduced (p < 0.05) during I and even lower in WO, compared to S. Probiotic bacteria could neither integrate nor persist in dental biofilm and saliva but did influence the growth of streptococci in biofilm and saliva.

Altered Airway Microbiota Composition in Patients With Pulmonary Hypertension.

Alteration in microbiota composition of respiratory tract has been reported in the progression of many chronic lung diseases, yet, the correlation and causal link between respiratory tract microbiota and the disease development of pulmonary hypertension (PH) remain largely unknown. This study aims to define and compare the respiratory microbiota composition in pharyngeal swab samples between patients with PH and reference subjects. A total of 118 patients with PH and 79 reference subjects were recruited, and the pharyngeal swab samples were collected to sequence the 16S ribosomal RNA (16S rRNA) V3-V4 region of respiratory microbiome. The relative abundances in patients with PH were profoundly different from reference subjects. The Ace and Sobs indexes indicated that the microbiota richness of pharynx value is significantly higher; while the community diversity value is markedly lower in patients with PH, comparing to those of the reference subjects. The microbiota on pharynx showed a different profile between the 2 groups by principal component analysis. The linear discriminant analysis effect size also revealed a significantly higher proportion of Streptococcus, Lautropia, and Ralstonia in patients with PH than reference subjects. The linear discriminant analysis effect size output, which represents the microbial gene functions, suggest genes related to bacterial invasion of epithelial cells, bacterial toxins were enhanced, while genes related to energy metabolism, protein digestion and absorption, and cell division pathways were attenuated in patients with PH versus reference subjects. In summary, our study reports the first systematic definition and divergent profile of the upper respiratory tract microbiota between patients with PH and reference subjects.

Etiology, microbiological isolates, and antibiotic susceptibilities in culture-proven pediatric endophthalmitis: a 9-year review

PurposeTo analyze the etiology, microbiological isolates, and antibiotic susceptibilities of endophthalmitis in pediatric patients.MethodsPatients aged < 18 years with culture-positive endophthalmitis in Zhongshan Ophthalmic Center between January 2010 and December 2018 were included retrospectively.ResultsA total of 127 patients (127 eyes) were included, and 108 (85%) had posttraumatic endophthalmitis. Streptococcus (21.4%), coagulase-negative Staphylococcus (14.5%), Aspergillus (6.9%), and Bacillus cereus (5.3%) were the common organisms. The proportion of Streptococcus decreased with age (40.0% in 0–3 years, 16.3% in 4–12 years, and 6.3% in 13–17 years), while coagulase-negative Staphylococcus increased from 5.7% to 18.8%. Overall, fluoroquinolones achieved the highest antibiotic susceptibility rate (> 95%), while the susceptibility of isolated bacteria to tobramycin and cefazolin was only 60.2% and 59.4%, respectively. The susceptibility rates of Gram-positive cocci to cephalosporins were nearly 90%. For Gram-negative bacilli, susceptibility to neomycin was 91.3%.ConclusionTrauma was the main etiology for pediatric endophthalmitis. Although Streptococcus was the most prevalent organism in general, the dominant pathogen varied with age, which merits clinical attention. Fluoroquinolones showed the highest antibiotic efficacy; however, commonly used antibiotics tobramycin and cefazolin showed relatively low antibiotic susceptibility. Thus, antibiotic resistance in pediatric populations merits clinical attention.

Dynamic changes of microbiota and texture properties during the ripening of traditionally prepared cheese of China.

The dynamic changes of microbiota assessed by high-throughput sequencing and texture properties of handmade cheese were investigated during ripening time. Streptococcus and Lactococcus were found to be the most predominant genera. The proportion of Streptococcus was decreased from 48 to 32% and the proportion of Lactococcus was increased from 41 to 55% with ripening time from 1 to 120 days. Mould and yeast such as Paecilomyces, Candida, Issatchenkia, Rhodotorula, Cryptococcus and Trichosporon were observed. The regression analysis between composition and textural properties indicated that the hardness was increased along with the rising of soluble nitrogen, while the increased soluble nitrogen could result in lower cohesiveness, and the increased fat in dry matter resulted in lower resilience. The physic-chemical parameters were correlated with secondary microbiota such as Cryptococcus and Candida according to the multivariate association analysis (p < 0.05). These findings could provide a baseline to improve the product quality and preserve the traditional characteristics of handmade cheese.

Antibiotic use and resistance in Belgium: the impact of two decades of multi-faceted campaigning

ABSTRACT Objective: To present an overview of almost two decades of multi-faceted campaigning by the Belgian Antibiotic Policy Coordination Committee (BAPCOC) and partners, and its impact on public and prescribers’ awareness, outpatient antibiotic use, its cost and antimicrobial resistance in Belgium.Methods: Awareness of both public and prescribers was assessed through pre- and post-campaign interviews and surveys. Outpatient antibiotic use was evaluated using national reimbursement data expressed in number of defined daily doses and packages (a good proxy for treatments) per 1000 inhabitants per day (DID and PID, respectively) from July 1997 to June 2018. Its cost was studied using the same data expressed in number of euros per 1000 inhabitants per day. Antimicrobial resistance was evaluated between 1986 and 2017 using national data on the proportion of Streptococcus pneumoniae isolates not susceptible to penicillins, macrolides and tetracyclines.Results: Antibiotic awareness improved significantly, with general practitioners preferred by 87.5% of respondents as source of information. The Belgian outpatient antibiotic use has decreased by 12.8% in DID and by 42.8% in PID in the 2017-2018 winter compared to the winter before the start of its public awareness campaigns (1999-2000). This evolution coincided with decreasing costs for antibiotics and decreasing antimicrobial resistance. Despite multi-faceted campaigning, outpatient antibiotic use and use of broad-spectrum antibiotics, especially fluoroquinolones and amoxicillin with clavulanic acid, are still high in Belgium.Conclusion: Almost two decades of multi-faceted campaigning coincide with improvements in antibiotic awareness among the public and prescribers, outpatient antibiotic use and resistance. Nevertheless, additional efforts are needed to reach the targets set in BAPCOC’s national action plan 2014-2019. Therefore, a new national action plan was developed for 2020-2024 using a One Health approach.

A nanocarrier system that potentiates the effect of miconazole within different interkingdom biofilms

ABSTRACT Background Novel and new therapeutic strategies capable of enhancing the efficacy of existing antimicrobials is an attractive proposition to meet the needs of society. Objective This study aimed to evaluate the potentiating effect of a miconazole (MCZ) nanocarrier system, incorporated with iron oxide nanoparticles (IONPs) and chitosan (CS) (IONPs-CS-MCZ). This was tested on three representative complex interkingdom oral biofilm models (caries, denture and gingivitis). Materials and methods The planktonic and sessile minimum inhibitory concentrations (MICs) of IONPs-CS-MCZ against different Candida albicans strains were determined, as well as against all represented bacterial species that formed within the three biofilm models. Biofilms were treated for 24 hours with the IONPs-CS nanocarrier system containing MCZ at 64 mg/L, and characterized using a range of bioassays for quantitative and qualitative assessment. Results MIC results generally showed that IONPs-CS-MCZ was more effective than MCZ alone. IONPs-CS-MCZ also promoted reductions in the number of CFUs, biomass and metabolic activity of the representative biofilms, as well as altering biofilm ultrastructure when compared to untreated biofilms. IONPs-CS-MCZ affected the composition and reduced the CFEs for most of the microorganisms present in the three evaluated biofilms. In particular, the proportion of streptococci in the biofilm composition were reduced in all three models, whilst Fusobacterium spp. percentage reduced in the gingivitis and caries models, respectively. Conclusion In conclusion, the IONPs-CS-MCZ nanocarrier was efficient against three in vitro models of pathogenic oral biofilms, showing potential to possibly interfere in the synergistic interactions among fungal and bacterial cells within polymicrobial consortia.

Subgingival Microbiota of Mexicans with Type 2 Diabetes with Different Periodontal and Metabolic Conditions.

Background: Type-2-Diabetes (T2D) and Periodontitis are major inflammatory diseases. However, not much is known about the specific subgingival microbiota in Mexicans with diabetes and metabolic dysbiosis. The aim of this study was to describe the subgingival microbiota of Mexicans with T2D and the different periodontal and metabolic conditions, through “Checkerboard” DNA–DNA hybridization. Methods: Subjects were divided into two groups—periodontal-health (PH) (PH_non-T2D; n = 59, PH_T2D; n = 14) and generalized-periodontitis (GP) (GP_non-T2D; n = 67, GP_T2D; n = 38). Obesity (BMI ≥ 30 kg/m2) and serum levels of glycated-hemoglobin (HbA1c), total-lipids, triglycerides, total-cholesterol, high-density-lipids, and low-density-lipids were measured for the T2D individuals. Subgingival microbial identification was processed for 40 species through DNA-probes. Results: Subjects with T2D harbored significantly higher mean total levels (PH: p < 0.001, and GP_NS), a lower proportion of “red” complex (GP: p < 0.01), a higher proportion of “yellow” (GP; p < 0.001), and “orange” (GP; p < 0.01) complex than the non-T2D. GP_T2D individuals exhibited a greater proportion of putative-species—Campylobacter gracilis and S. constellatus (p < 0.001), and Parvimonas micra and Prevotella nigrescens (p < 0.01), than GP_non-T2D. T2D individuals with HbA1c > 8% had presented significantly higher mean pocket-depth and higher levels of G. morbillorum (p < 0.05) and those with obesity or dyslipidemia harbored higher levels, prevalence, or proportion of Streptococcus sp., Actinomyces sp., and Capnocytophaga sp. Conclusions: T2D individuals harbored a particular microbial profile different to non-T2D microbiota. Metabolic control was related to dysbiosis of microbiota—HbA1c>8% related to periodontitis and obesity or dyslipidemia with the predominance of saccharolytic bacteria, irrespective of their periodontal condition.

Trends in Hospitalization for Infective Endocarditis as a Reason for Admission or a Secondary Diagnosis

We postulate that the trends for infective endocarditis (IE) are different for patients admitted for this condition compared with those admitted for a different reason with IE as a secondary diagnosis. Using the Myocardial Infarction Data Acquisition System (MIDAS) database, we analyzed 21,443 records of patients hospitalized with diagnosis of IE from 1994 to 2015. There were 9,191 patients hospitalized with IE as the primary diagnosis, and 12,252 patients with IE as a secondary diagnosis. Piecewise linear models were used to detect changes in trends. A bootstrap method was used to assess the statistical significance of the slopes and break point of each model. Differences in co-morbidities and microbiological patterns were analyzed. Trend analysis showed a significant decrease in IE as the primary diagnosis starting in the year 2004 (p <0.01). Hospitalizations with IE as a secondary diagnosis showed a linear increase in incidence (p <0.001), without any change points. In primary diagnosis IE, the proportion of streptococci as a causative microorganism was higher compared with staphylococci (p <0.001). On the contrary, in secondary diagnosis IE, the proportion of staphylococci was higher than streptococci (p <0.001). The proportion of gram-negative and other organism IE was similar in both groups. In conclusion, this study showed 2 divergent temporal trends in hospitalizations for IE as a primary or secondary diagnosis starting in 2004. The profile of the microorganisms reveals a steady higher proportion of staphylococcal infection in secondary diagnosis IE compared with streptococcal infection. Different strategies are needed for the prevention of IE.

Effect of cereal processing (grinding to 3·5 mm or dry-rolling) in maize- or barley-based high-concentrate diets on rumen environment of beef cattle during the late fattening period

SUMMARYThe type and processing of cereals for beef cattle are key factors to maximize performance without increasing the risk of ruminal acidosis. The current work studied the effect of grinding (G) or dry-rolling (R) the cereals in a concentrate based on maize (M) or barley (B) on the rumen environment of eight 6-month-old Holstein calves, which received either M or B for 70 days, offered as G and R in two consecutive periods. Daily feed intake pattern, rumen fermentation traits, total rumen bacteria and relative proportions ofStreptococcus bovisandSelenomonas ruminantiumwere characterized twice in each period at 0, 4 and 8 h after feeding. Dry-rolling promoted a 0·25 reduction of concentrate intake during the first 4 h after feeding. Neither cereal type nor its processing form promoted differences in ruminal fermentation at 0 and 4 h; however, 8 h after feeding R cereals resulted in higher rumen pH (6·17v.5·71) and lower concentration of lactic acid (88·1v.156 mg/l) and volatile fatty acids (only in diet B, 118v.164 mm/l) compared with G. Little effect of dietary factors in the target rumen microorganisms were observed. The more balanced fermentation observed with R cereals may be explained by the lower concentrate intake promoted during the first 4 h, coupled with a more difficult access of bacterial enzymes to their starch, thus reducing its fermentation rate. Therefore, feeding dry-rolled cereals may be useful to reduce the risk of acidosis by regulating the intake pattern of the concentrate and/or its fermentation rate.

L-arginine destabilizes oral multi-species biofilm communities developed in human saliva.

The amino acid L-arginine inhibits bacterial coaggregation, is involved in cell-cell signaling, and alters bacterial metabolism in a broad range of species present in the human oral cavity. Given the range of effects of L-arginine on bacteria, we hypothesized that L-arginine might alter multi-species oral biofilm development and cause developed multi-species biofilms to disassemble. Because of these potential biofilm-destabilizing effects, we also hypothesized that L-arginine might enhance the efficacy of antimicrobials that normally cannot rapidly penetrate biofilms. A static microplate biofilm system and a controlled-flow microfluidic system were used to develop multi-species oral biofilms derived from pooled unfiltered cell-containing saliva (CCS) in pooled filter-sterilized cell-free saliva (CFS) at 37oC. The addition of pH neutral L-arginine monohydrochloride (LAHCl) to CFS was found to exert negligible antimicrobial effects but significantly altered biofilm architecture in a concentration-dependent manner. Under controlled flow, the biovolume of biofilms (μm3/μm2) developed in saliva containing 100-500 mM LAHCl were up to two orders of magnitude less than when developed without LAHCI. Culture-independent community analysis demonstrated that 500 mM LAHCl substantially altered biofilm species composition: the proportion of Streptococcus and Veillonella species increased and the proportion of Gram-negative bacteria such as Neisseria and Aggregatibacter species was reduced. Adding LAHCl to pre-formed biofilms also reduced biovolume, presumably by altering cell-cell interactions and causing cell detachment. Furthermore, supplementing 0.01% cetylpyridinium chloride (CPC), an antimicrobial commonly used for the treatment of dental plaque, with 500 mM LAHCl resulted in greater penetration of CPC into the biofilms and significantly greater killing compared to a non-supplemented 0.01% CPC solution. Collectively, this work demonstrates that LAHCl moderates multi-species oral biofilm development and community composition and enhances the activity of CPC. The incorporation of LAHCl into oral healthcare products may be useful for enhanced biofilm control.

Microbiota diversity and stability of the preterm neonatal ileum and colon of two infants

The composition of the microbiota associated with the human ileum and colon in the early weeks of life of two preterm infants was examined, with particular emphasis on the Lactobacillus and Bifidobacterium members. Culturing work showed that bifidobacteria and lactobacilli in the ileostomy changed over time, compared with the colostomy effluent where there was far less variation. The colostomy infant was dominated by two phyla, Actinobacteria and Firmicutes, while in the ileostomy samples, Proteobacteria emerged at the expense of Actinobacteria. Bacteroidetes were only detected following the reversal of the ileostomy in the final fecal sample and were not detected in any colonic fluid samples. Clostridia levels were unstable in the colostomy fluid, suggesting that the ileostomy/colostomy itself influenced the gut microbiota, in particular the strict anaerobes. Pyrosequencing analysis of microbiota composition indicated that bifidobacteria and lactobacilli are among the dominant genera in both the ileal and colonic fluids. Bifidobacteria and lactobacilli levels were unstable in the ileostomy fluid, with large reductions in numbers and relative proportions of both observed. These decreases were characterized by an increase in proportions of Streptococcus and Enterobacteriaceae. Clostridium was detected only in the colonic effluent, with large changes in the relative proportions over time.

Microbial composition of dental plaque microflora on first molars with orthodontic bands and brackets, and the acidogenic potential of these bacteria

PurposeIn order to elucidate the characteristics of orthodontic appliance-associated dental plaque, this study aimed to profile the microflora and to estimate the acidogenic potential of supragingival plaque on first molars with orthodontic bands or brackets or without appliances. Material and methodsSupragingival plaque samples from the surface of upper and lower first molars with orthodontic bands or brackets or without appliances in 6 subjects (age, 11–30 years) were cultured anaerobically on blood agar plates. Isolated bacteria were identified by 16S rRNA sequencing. The acidogenicity of isolated bacteria was examined using fastidious anaerobe agar plates containing bromocresol. ResultsBacterial growth (log CFU/mg) was 6.6±6.5, 6.9±7.1, and 7.4±7.6 in samples obtained from molars with bands, brackets, and without appliances, respectively. Actinomyces (43.5 and 40.0%) and Streptococcus (23.5 and 34.7%) were the predominant species present on molars with orthodontic brackets and without appliances, respectively. In contrast, the proportion of Streptococcus (44.4%) was higher than that of Actinomyces (17.6%) on molars with orthodontic bands (P<0.01). The proportions of acidogenic bacteria in plaque samples from molars with bands, brackets, and without appliances were 74.5%, 71.3%, and 81.6%, respectively, although these differences were not statistically significant. Discussion and conclusionThese results indicate that there are differences in the microbial composition and acidogenic potential of supragingival plaque from first molars with bands, brackets, or without appliances, and suggest that supragingival plaque on teeth with brackets carries predominantly periodontitis-associated bacteria but less caries-associated bacteria.

Difference in initial dental biofilm accumulation between night and day

Objective. The study of initial microbial colonization on dental surfaces is a field of intensive research because of the aetiological role of biofilms in oral diseases. Most previous studies of de novo accumulation and composition of dental biofilms in vivo do not differentiate between biofilms formed during day and night. This study hypothesized that there is a diurnal variation in the rate of accumulation of bacteria on solid surfaces in the oral cavity. Materials and methods. In situ biofilm from healthy individuals was collected for 12 h during day and night, respectively, subjected to fluorescent in situ hybridization and visualized using confocal laser scanning microscopy. Results. Analysis of the biofilms using stereological methods and digital image analysis revealed a consistent statistically significant difference between both the total number of bacteria and the biovolume in the two 12-h groups (p = 0.012), with the highest accumulation of bacteria during daytime (a factor of 8.8 and 6.1 higher, respectively). Hybridization with probes specific for streptococci and Actinomyces naeslundii indicated a higher proportion of streptococci in biofilms grown during daytime as compared to night-time. No differences could be observed for A. naeslundii. The degree of microbial coverage and the bacterial composition varied considerably between different individuals. Conclusion. The data provide firm evidence that initial biofilm formation decreases during the night, which may reflect differences in the availability of salivary nutrients. This finding is of significant importance when studying population dynamics during experimental dental biofilm formation.