One-year water-ageing of calcium phosphate composite containing nano-silver and quaternary ammonium to inhibit biofilms

Dental composites are commonly used restorative materials; however, secondary caries due to biofilm acids remains a major problem. The objectives of this study were (1) to develop a composite containing quaternary ammonium dimethacrylate (QADM), nanoparticles of silver (NAg), and nanoparticles of amorphous calcium phosphate (NACP), and (2) to conduct the first investigation of the mechanical properties, biofilm response and acid production vs water-ageing time from 1 day to 12 months. A 4 × 5 design was utilized, with four composites (NACP-QADM composite, NACP-NAg composite, NACP-QADM-NAg composite, and a commercial control composite), and five water-ageing time periods (1 day, and 3, 6, 9, and 12 months). After each water-ageing period, the mechanical properties of the resins were measured in a three-point flexure, and antibacterial properties were tested via a dental plaque biofilm model using human saliva as an inoculum. After 12 months of water-ageing, NACP-QADM-NAg had a flexural strength and elastic modulus matching those of the commercial control (P40.1). Incorporation of QADM or NAg into the NACP composite greatly reduced biofilm viability, metabolic activity and acid production. A composite containing both QADM and NAg possessed a stronger antibacterial capability than one with QADM or NAg alone (Po0.05). The anti-biofilm activity was maintained after 12 months of water-ageing and showed no significant decrease with increasing time (P40.1). In conclusion, the NACP-QADM-NAg composite decreased biofilm viability and lactic acid production, while matching the load-bearing capability of a commercial composite. There was no decrease in its antibacterial properties after 1 year of water-ageing. The durable antibacterial and mechanical properties indicate that NACP-QADM-NAg composites may be useful in dental restorations to combat caries.     

Evaluation of three-dimensional biofilms on antibacterial bonding agents containing novel quaternary ammonium methacrylates

Antibacterial adhesives are promising to inhibit biofilms and secondary caries. The objectives of this study were to synthesize and incorporate quaternary ammonium methacrylates into adhesives, and investigate the alkyl chain length effects on three-dimensional biofilms adherent on adhesives for the first time. Six quaternary ammonium methacrylates with chain lengths of 3, 6, 9, 12, 16 and 18 were synthesized and incorporated into Scotchbond Multi-Purpose. Streptococcus mutans bacteria were cultured on resin to form biofilms. Confocal laser scanning microscopy was used to measure biofilm thickness, live/dead volumes and live-bacteria percentage vs. distance from resin surface. Biofilm thickness was the greatest for Scotchbond control; it decreased with increasing chain length, reaching a minimum at chain length 16. Live-biofilm volume had a similar trend. Dead-biofilm volume increased with increasing chain length. The adhesive with chain length 9 had 37% live bacteria near resin surface, but close to 100% live bacteria in the biofilm top section. For chain length 16, there were nearly 0% live bacteria throughout the three-dimensional biofilm. In conclusion, strong antibacterial activity was achieved by adding quaternary ammonium into adhesive, with biofilm thickness and live-biofilm volume decreasing as chain length was increased from 3 to 16. Antibacterial adhesives typically only inhibited bacteria close to its surface; however, adhesive with chain length 16 had mostly dead bacteria in the entire three-dimensional biofilm. Antibacterial adhesive with chain length 16 is promising to inhibit biofilms at the margins and combat secondary caries.     

A novel protein-repellent dental composite containing 2-methacryloyloxyethyl phosphorylcholine

Secondary caries due to biofilm acids is a primary cause of dental composite restoration failure.To date,there have been no reports of dental composites that can repel protein adsorption and inhibit bacteria attachment.The objectives of this study were to develop a protein-repellent dental composite by incorporating 2-methacryloyloxyethyl phosphorylcholine(MPC) and to investigate for the first time the effects of MPC mass fraction on protein adsorption,bacteria attachment,biofilm growth,and mechanical properties.Composites were synthesized with 0(control),0.75%,1.5%,2.25%,3%,4.5%and 6%of MPC by mass.A commercial composite was also tested as a control.Mechanical properties were measured in three-point flexure.Protein adsorption onto the composite was determined by the microbicinchoninic acid method.A human saliva microcosm biofilm model was used.Early attachment at 4 h,biofilm at 2 days,live/dead staining and colony-forming units(CFUs) of biofilms grown on the composites were investigated.Composites with MPC of up to 3%had mechanical properties similar to those without MPC and those of the commercial control,whereas 4.5%and 6%MPC decreased the mechanical properties(P<0.05).Increasing MPC from 0 to 3%reduced the protein adsorption on composites(P<0.05).The composite with 3%MPC had protein adsorption that was 1/12 that of the control(P<0.05).Oral bacteria early attachment and biofilm growth were also greatly reduced on the composite with 3%MPC,compared to the control(P<0.05).In conclusion,incorporation of MPC into composites at 3%greatly reduced protein adsorption,bacteria attachment and biofilm CFUs,without compromising mechanical properties.Protein-repellent composites could help to repel bacteria attachment and plaque build-up to reduce secondary caries.The protein-repellent method might be applicable to other dental materials.     

Novel rechargeable calcium phosphate nanoparticle-containing orthodontic cement

White spot lesions (WSLs), due to enamel demineralization, occur frequently in orthodontic treatment. We recently developed a novel rechargeable dental composite containing nanoparticles of amorphous calcium phosphate (NACP) with long-term calcium (Ca) and phosphate (P) ion release and caries-inhibiting capability. The objectives of this study were to develop the first NACP-rechargeable orthodontic cement and investigate the effects of recharge duration and frequency on the efficacy oftion re-release. The rechargeable cement consisted of pyromellitic glycerol dimethacrylate (PMGDM) and ethoxylated bisphenol A dimethacrylate (EBPADMA). NACP was mixed into the resin at 40% by mass. Specimens were tested for orthodontic bracket shear bond strength (SBS) to enamel, Ca and P ion initial release, recharge and re-release. The new orthodontic cement exhibited an SBS similar to commercial orthodontic cement without CaP release (P>0.1). Specimens after one recharge treatment (e.g., 1 min immersion in recharge solution repeating three times in one day, referred to as"1 min 3 times") exhibited a substantial and continuous re-release of Ca and P ions for 14 days without further recharge. The ion re-release did not decrease with increasing the number of recharge/re-release cycles (P>0.1). The ion re-release concentrations at 14 days versus various recharge treatments were as follows:1 min 3 times>3 min 2 times>1 min 2 times>6 min 1 time>3 min 1 time>1 min 1 time. In conclusion, although previous studies have shown that NACP nanocomposite remineralized tooth lesions and inhibited caries, the present study developed the first orthodontic cement with Ca and P ion recharge and long-term release capability. This NACP-rechargeable orthodontic cement is a promising therapy to inhibit enamel demineralization and WSLs around orthodontic brackets.     

Differences of sensitivity to autologous cytotoxic lymphocytes between primary tumor and its cervical lymph node metastases

Antigenic differences between primary tumors and their cervical lymph node metastases of 12 patients with head and neck cancers were examined by measuring their sensitivity to cytotoxic lymphocytes (CL). Cytotoxicity was induced by autologous mixed lymphocyte (CL). Cytotoxicity was induced by autologous mixed lymphocyte tumor cell culture (MLTC), and further cultivation with recombinant interleukin-2 (rIL-2). The effector cells which were used in this study consisted of OKT3+8+ and OKT3+4+ subpopulations. Their cytotoxic nature was different from lymphokine activated killer cell (LAK cell) activity. Cytotoxicity of CLs stimulated by autologous primary tumor cells (CLP) was observed in 7 out of 12 patients (58.3%). In contrast, cytotoxicity of CLs stimulated by metastatic tumor cells (CLM) was observed in 4 out of 12 patients (33.3%). In the cases in which both CLP and CLM were successfully induced, cross-reactivity tests and cold target inhibition tests were performed. These results suggested that a reduction in immunogenicity had occurred at the metastatic site, and sensitivity against autologous CL was different between primary and metastatic tumor cells.     

In vitro Antimicrobial Activity of SinuSurf™

Background: Topical surfactant therapy has been found to be effective in the management of recalcitrant chronic rhinosinusitis. Objective: To determine in vitro the antibacterial potential of SinuSurf?, a previously commercially available sinonasal surfactant. Methods: Methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa (PA) cultures were grown in the presence or absence of serial dilutions of mupirocin or gentamicin with and without SinuSurf and quantified by colony-forming units (CFUs). Biofilm formation was also assessed. Finally, bacterial growth was evaluated in sinus irrigation bottles inoculated with MRSA or PA and rinsed daily with SinuSurf. Results: SinuSurf alone evinced a 3-log (1,000-fold) and 6-log (10(6)-fold) reduction in CFUs for MRSA and PA, respectively. The combination of SinuSurf with a 1:10 dilution mupirocin and 1:100 dilution gentamicin demonstrated complete bacterial eradication. Similar concentrations of antibiotic dilutions alone demonstrated bacterial growth. SinuSurf averaged an 83% MRSA and 76% PA reduction in biofilm formation. Bottle contamination evaluation demonstrated reduction of MRSA and PA (p < 0.05) with SinuSurf. Conclusion: Biofilms have been demonstrated in chronic rhinosinusitis patients and implicated in recalcitrant disease. Our in vitro data demonstrates the addition of SinuSurf improved the effectiveness of a lower concentration of topical antibiotics in biofilm mass and viability.     

Primer containing dimethylaminododecyl methacrylate kills bacteria impregnated in human dentin blocks

Antibacterial dimethylaminododecyl methacrylate (DMADDM) was recently synthesized. The objectives of this study were to:(1) investigate antibacterial activity of DMADDM-containing primer on Streptococcus mutans impregnated into dentin blocks for the first time, and (2) compare the antibacterial efficacy of DMADDM with a previous quaternary ammonium dimethacrylate (QADM). Scotchbond Multi-Purpose (SBMP) bonding agent was used. DMADDM and QADM were mixed into SBMP primer. Six primers were tested:SBMP control primer P, P+2.5%DMADDM, P+5%DMADDM, P+7.5%DMADDM, P+10%DMADDM, and P+10%QADM. S. mutans were impregnated into human dentin blocks, and each primer was applied to dentin to test its ability to kill bacteria in dentinal tubules. Bacteria in dentin were collected via a sonication method, and the colony-forming units (CFU) and inhibition zones were measured. The bacterial inhibition zone of P+10%DMADDM was 10 times that of control primer (Po0.05). CFU in dentin with P+10%DMADDM was reduced by three orders of magnitude, compared with control. DMADDM had a much stronger antibacterial effect than QADM, and antibacterial efficacy increased with increasing DMADDM concentration. Dentin shear bond strengths were similar among all groups (P40.1). In conclusion, antibacterial DMADDM-containing primer was validated to kill bacteria inside dentin blocks, possessing a much stronger antibacterial potency than the previous QADM. DMADDM-containing bonding agent was effective in eradicating bacteria in dentin, and its efficacy was directly proportional to DMADDM mass fraction. Therefore, DMADDM may be promising for use in bonding agents as well as in other restorative and preventive materials to inhibit bacteria.     

Role of sortase in Streptococcus mutans under the effect }f nicotine

Streptococcus mutans is a common Gram-positive bacterium and plays a significant role in dental caries. Tobacco and/or nicotine have documented effects on S. mutans growth and colonization. Sortase A is used by many Gram-positive bacteria, including S. mutans, to facilitate the insertion of certain cell surface proteins, containing an LPXTGX motif such as antigen 1/11. This study examined the effect of nicotine on the function of sortase A to control the physiology and growth of S. mutans using wild-type S. mutans NG8, and its isogenic sortase-defective and -complemented strains. Briefly, the strains were treated with increasing amounts of nicotine in planktonic growth, biofilm metabolism, and sucrose-induced and saliva-induced antigen I/ll-dependent biofilm formation assays. The strains exhibited no significant differences with different concentrations of nicotine in planktonic growth assays. However, they had significantly increased （P~〈 0.05） biofilm metabolic activity （2- to 3-fold increase） as the concentration of nicotine increased. Furthermore, the sortase-defective strain was more sensitive metabolically to nicotine than the wild-type or sortase-complemented strains. All strains had significantly increased sucrose-induced biofilm formation （2- to 3-fold increase） as a result of increasing concentrations of nicotine. However, the sortase-defective strain was not able to make as much sucrose- and saliva-induced biofilm as the wild-type NG8 did with increasing nicotine concentrations. These results indicated that nicotine increased metabolic activity and sucrose-induced biofilm formation. The saliva-induced biofilm formation assay and qPCR data suggested that antigen 1/11 was upregulated with nicotine but biofilm was not able to be formed as much as wild-type NG8 without functional sortase A.     

Effect of Galla chinensis on the In Vitro Remineralization of Advanced Enamel Lesions

Aim The effect of Galla chinensis on de-/re-mineralization of advanced enamel lesions was investigated by using micro-CT in a prolonged in vitro experiment.Methodology Baseline mineral contents of sound enamels were first analyzed.Then lesions were produced in an KH2PO4,and pH=4.5) for 21 days,with thrice daily three-minute treatments,divided into four groups:Group A,4 000 ppm crude aqueous extract of Galla chinensis (GCE);Group B,4 000 ppm gallic acid;Group C,1 000 ppm F aq.(as NaF,positive control);Group D,deionized water (negative control).Next,the blocks were CaCl2,0.9 mmol@L-1 KH2PO4,0.1 ppm E and pH=7.0) for 200 days.Mineral loss (ML) in each region of interest (ROI) and integrated mineral loss (IML) of the lesions were calculated (comparing with baseline mineral content of sound enamel) at different time points.Results After 21 days demineralization,fluoride treatment showed a statistically significant demineralization-inhibiting effect among the four groups,and after 200 days of remineralization,mineral content recovery was ordered (lowest to highest) as A=C＜B＜D.Conclusion GCE could slow down the remineralization of enamel in the surface layer and thereby facilitate ion transport into the lesion body.The mechanism of Galla chinensis in enhancing the remineralization of dental caries is different from fluoride.     

Targeted Antimicrobial Therapy Against Streptococcus mutans Establishes Protective Non-cariogenic Oral Biofilms and Reduces Subsequent Infection

Aim Dental biofilms are complex communities composed largely of harmless bacteria. Certain pathogenic species including Streptococcus mutans (S. Mutans) can become predominant when host factors such as dietary sucrose intake imbalance the biofilm ecology. Current approaches to control S. Mutans infection are not pathogen-specific and eliminate the entire oral community along with any protective benefits provided. Here, we tested the hypothesis that removal of S. Mutans from the oral community through targeted antimicrobial therapy achieves protection against subsequent 5. Mutans colonization. Methodology Controlled amounts of S. Mutans were mixed with S. Mutans-free saliva, grown into biofilms and visualized by antibody staining and cfu quantization. Two specifically-targeted antimicrobial peptides (STAMPs) against S. Mutans were tested for their ability to reduce S. Mutans biofilm incorporation upon treatment of the inocula. The resulting biofilms were also evaluated for their abilityto resist subsequent exogenous S. Mutans colonization. Results S. Mutans colonization was considerably reduced (9 ±0.4 fold reduction, P=0.01) when the surface was preoccupied with saliva-derived biofilms. Furthermore, treatment with S. Mutans-specific STAMPs yielded S. Mutans-deficient biofilms with significant protection against further S. Mutans colonization (5 minutes treatment: 38 ± 13 fold reduction P=0.01; 16 hours treatment: 96 ±28 fold reduction P=0.07).Conclusion S. Mutans infection is reduced by the presence of existing biofilms. Thus maintaining a healthy or "normal" biofilm through targeted antimicrobial therapy (such as the STAMPs) could represent an effective strategy for the treatment and prevention of S. Mutans colonization in the oral cavity and caries progression.     

Role of saliva proteinase 3 in dental caries

Salivary analysis can be used to assess the severity of caries. Of the known salivary proteins, a paucity of information exists concerning the role of proteinase 3 (PR3), a serine protease of the chymotrypsin family, in dental caries. Whole, unstimulated saliva was collected from children with varying degrees of active caries and tested using a Human Protease Array Kit and an enzyme-linked immunosorbent assay. A significantly decreased concentration of salivary PR3 was noted with increasing severity of dental caries (P<0.01); a positive correlation (r=0.87; P<0.01; Pearson''s correlation analysis) was also observed between salivary pH and PR3 concentration. In an antibacterial test, a PR3 concentration of 250 ng·mL⁻¹ or higher significantly inhibited Streptococcus mutans UA159 growth after 12 h of incubation (P<0.05). These studies indicate that PR3 is a salivary factor associated with the severity of dental caries, as suggested by the negative relationship between salivary PR3 concentration and the severity of caries as well as the susceptibility of S. mutans to PR3.     

Alanine racemase is essential for the growth and interspecies competitiveness of Streptococcus mutans

D-alanine (D-Ala) is an essential amino acid that has a key role in bacterial cell wall synthesis. Alanine racemase (Alr) is a unique enzyme that interconverts L-alanine and D-alanine in most bacteria, making this enzyme a potential target for antimicrobial drug development. Streptococcus mutans is a major causative factor of dental caries. The factors involved in the survival, virulence and interspecies interactions of S. mutans could be exploited as potential targets for caries control. The current study aimed to investigate the physiological role of Alr in S. mutans. We constructed alr mutant strain of S. mutans and evaluated its phenotypic traits and interspecies competitiveness compared with the wild-type strain. We found that alr deletion was lethal to S. mutans. A minimal supplement of D-Ala (150μg·mL?1) was required for the optimal growth of the alr mutant. The depletion of D-alanine in the growth medium resulted in cell wall perforation and cell lysis in the alr mutant strain. We also determined the compromised competitiveness of the alr mutant strain relative to the wild-type S. mutans against other oral streptococci (S. sanguinis or S. gordonii), demonstrated using either conditioned medium assays or dual-species fluorescent in situ hybridization analysis. Given the importance and necessity of alr to the growth and competitiveness of S. mutans, Alr may represent a promising target to modulate the cariogenicity of oral biofilms and to benefit the management of dental caries.     

Effect of Galla chinensis on the remineralization of two bovine root lesions morphous in vitro

The present study aims to evaluate the effect of Galla chinensis compounds on the remineralization of two artificial root lesions morphous in vitro.Sixty bovine dentine blocks were divided into two groups and individually treated with two levels of demineralization solutions to form erosive and subsurface artificial carious lesions in vitro.Each group was then divided into three subgroups,each of which were treated with a remineralization solution(positive control),deionized water(negative control),or 4 000 mg?L 21 aqueous solutions of Galla chinensis extract.The dentine blocks were then subjected to a pH-cycling regime for 7 days.During the first 4 days,the daily cycle included 21-h deal and 3-h demineralization applications.The dentine blocks were dealt with the entire day during the remaining 3 days.Two specimens from each of the treatment groups were selected and observed under a polarized light microscope.Data collected using a laser scanning confocal microscope were computerized and analyzed.Galla chinensis extract clearly enhanced the remineralization of both erosive lesion and subsurface lesion patterns in the specimens(P,0.05).The level of remineralization of the erosive lesion by Galla chinensis extract was lower than that of the subsurface lesion(P,0.05).In addition,the remineralization of the subsurface lesion by Galla chinensis extract was higher than that of the remineralization solution(P,0.05).No significant difference between the remineralization of erosive lesions by Galla chinensis extract and the remineralization solution was observed(P.0.05).So Galla chinensis extract has the potential to improve the remineralization of artificial root lesions under dynamic pH-cyclic conditions,indicating its potential use as a natural remineralization medicine.     

Microbiology of acute and chronic maxillary sinusitis associated with an odontogenic origin

OBJECTIVES:: To study the microbiology of sinusitis associated with odontogenic origin. METHODS:: Aspirates of 20 acutely and 28 chronically infected maxillary sinuses that were associated with odontogenic infection were processed for aerobic and anaerobic bacteria. RESULTS:: A total of 66 isolates were recovered from the 20 cases of acute sinusitis (3.3/specimen), 16 aerobic and facultatives, and 50 anaerobic. Aerobes alone were recovered in 2 (10%) specimens, anaerobes only in 10 (50%), and mixed aerobic and anaerobic bacteria in 8 (40%). The predominant aerobic were alpha-hemolytic streptococci (5), microaerophilic streptococci (4), and Staphylococcus aureus (2). The predominant anaerobes were anaerobic Gram-negative bacilli (22), Peptostreptococcus (12), and Fusobacterium spp. (9). A total of 98 isolates were recovered from the 28 cases of chronic sinusitis (3.5/patient): 21 aerobic and facultatives and 77 anaerobic. Aerobes were recovered in 3 (11%) instances, anaerobes only in 11 (39%), and mixed aerobic and anaerobic bacteria in 14 (50%). The predominant aerobes were alpha-hemolytic streptococci (7), microaerophilic streptococci (4), and S. aureus (5). The predominant anaerobes were Gram-negative bacilli (41), Peptostreptococcus (16), and Fusobacterium spp. (12). Thirteen beta-lactamase-producing bacteria (BLPB) were recovered from 10 (50%) patients with acute sinusitis and 25 BLPB from 21 (75%) patients with chronic sinusitis. No correlation was found between the predisposing odontogenic conditions and the microbiological findings. CONCLUSIONS:: These data illustrate the similar microbiology of acute and chronic maxillary sinusitis associated with odontogenic infection where anaerobic bacteria predominate in both types of infections.     

Causes of lethal outcomes in croup syndrome in children

The paper reports 40 cases of lethal outcomes in children with croup syndrome treated in Morozov Children's Moscow City Hospital in 1985-1998. 92.5% of them died of severe pneumonia complications, 7.5%--of sepsis. 70% of the deceased were infants aged 0-2 years, 75% of them were boys. All the children had aggravated premorbid background. The sputum and organ tissues contained in most cases association of viruses with staphylococci and streptococci resistant to standard antibiotics (penicillin, ampicillin, cefazoline). The conclusion is made that children with croup died primarily of severe pneumonia complications in low systemic reactivity and bacterial-viral association of the agents resistant to the antibacterial therapy.     

细菌生物膜在急性中耳炎大鼠中耳腔的形成特点及意义

目的 通过观察细菌生物膜在急性中耳炎大鼠中耳腔的形成特点,分析其与急性中耳炎的关系,并探讨该中耳炎模型用于细菌生物膜研究的可行性.方法 30只健康雄性SD大鼠,采用随机数字表法分为实验组(24只)和对照组(6只).麻醉后将50μl肺炎链球菌悬液[1×108菌落形成单位(colony forming unit,CFU)/...     

Isolation of methicillin resistant Staphylococcus aureus from the surface and core of tonsils in children

BACKGROUND: The rate of recovery methicillin resistant Staphylococcus aureus (MRSA) in tonsils that were removed because of recurrent Group A-beta-hemolytic streptococci (GABHS) tonsillitis was not previously reported. MRSA may serve as a potential source for the spread of these organisms to other body sites as well to other individuals. This study investigated the rate of recovery of MRSA as well as other aerobic organisms from tonsils that were removed because of recurrent GABHS infection. PATIENTS AND METHODS: Core and surface tonsillar cultures for aerobic bacteria were obtained from 44 children who had tonsillectomy because of recurrent GABHS tonsillitis. RESULTS: A total of 167 aerobic isolates were recovered from the core of the tonsils (3.8/specimen) and 151 (3.4/specimen) were isolated from the surface. The predominant isolates were alpha-hemolytic streptococci, GABHS, S. aureus, gamma-hemolytic streptococci, Haemophilus influenzae and Moraxella catarrhalis. Concordance in the recovery of all organisms was noted in 117 instances. Certain organisms (i.e. GABHS, S. aureus) were recovered more often from the tonsillar cores, where other (i.e. alpha-hemolytic streptococci, gamma-hemolytic streptococci) were recovered more often from the tonsillar surface. Forty-four beta-lactamase-producing bacteria (BLPB) were recovered from 32 (75%) of the tonsillar cores, and 28 were isolated from 23 (52%) of the tonsillar surfaces. The predominant BLPB were S. aureus, H. influenzae and M. catarrhalis. Seven isolates of MRSA were recovered from the cores and two were isolated from the surface. Five of the core isolates and the two surface isolates were also BLPB. All of the MRSA isolates were resistant to oxacillin, penicillin and erythromycin and were susceptible to clindamycin, trimethoprim-sulfamethoxazole and vancomycin. CONCLUSIONS: These data demonstrated that in recurrently GABHS infected tonsils, BLPB was recovered from over 75% of the tonsillar cores, core tonsillar cultures yielded more GABHS and S. aureus, and MRSA was isolated from 16% of the tonsils.     

Protective effects of local administration of ciprofloxacin on the risk of pneumococcal meningitis after cochlear implantation

OBJECTIVES: To determine whether ciprofloxacin retains its antimicrobial activity after storage with Healon at ambient temperature and at 37 degrees C over 5 weeks and then to establish whether the application of ciprofloxacin/Healon onto scala tympani electrode arrays reduces the risk of meningitis in implanted rats inoculated with S. pneumoniae. STUDY DESIGN: In vitro laboratory and in vivo animal studies METHODS: The antibacterial activity of three concentrations of ciprofloxacin/Healon (7.5, 75, and 750 microg/mL) was examined over 5 weeks at both ambient temperature (23 degrees C) and body temperature (37 degrees C). Thirty-six rats (18 implanted with ciprofloxacin [750 mg/mL]/Healon-coated electrode array and 18 without the coating) were infected with S. pneumoniae 4 weeks after implantation by way of three different routes of infection (hematogenous, middle ear, and inner ear) and observed for the development of meningitis. RESULTS: The antibacterial activity of ciprofloxacin/Healon was maintained over 5 weeks at both 23 degrees C and 37 degrees C. The implanted rats with the ciprofloxacin/Healon-coated electrode array were protected from meningitis when the bacteria were given by way of the hematogenous route (Fisher's exact test, P = .008) but not when the bacteria were inoculated directly into the middle or inner ear. However, the time to develop meningitis was significantly longer in rats implanted with a coated array, irrespective of the route of inoculation (P < .05, log rank test). CONCLUSION: Our animal model demonstrated that a ciprofloxacin-coated electrode array can protect healthy implanted rats from meningitis when the route of infection is hematogenous and can delay the onset of meningitis when bacteria are inoculated directly into the middle or inner ear.     

Dental caries,cariogenic microorganisms and salivary properties of allergic rhinitis children

Objectives

The aim of this study was to observe the caries activities of allergic rhinitis patients in relation to salivary properties, salivary levels of mutans streptococci (MS) and lactobacillus (LB), oral hygiene and dietary habits.

Methods

The study groups composed of 40 allergic rhinitis children and 40 healthy controls aged between 6 and 13 years old. Demographic data, oral hygiene practices and dietary habits were recorded by questionnaire. For permanent teeth, caries experience was expressed as DMFT (D = decayed; M = missing; F = filled; T = teeth) index. The dmft (d = decayed; m = missing; f = filling; t = teeth) index was used for caries prevalence in primary teeth. Unstimulated salivary flow rate, salivary buffering capacity, and salivary MS and LB were also determined in children with allergic rhinitis and controls.

Results

There were no significant differences in combined DMFT/dmft, salivary flow rate, buffer capacity of saliva, salivary LB levels, and sugary food consumption between cases and controls (p > 0.05). However, higher salivary MS levels were observed in allergic rhinitis patients, compared to controls (P < 0.05).

Conclusions

Our results demonstrated that patients with allergic rhinitis had an increase in the level of salivary MS.     

Causes for massive bacterial colonization on mucosal membranes during infectious mononucleosis: implications for acute otitis media

OBJECTIVE: A common complication of virus-induced upper respiratory tract infections is acute otitis media caused by bacterial pathogens. Simultaneously, increased bacterial colonization in the nasopharynx occurs. Our intention in this study was to identify the causes of this increased colonization of bacteria by evaluating their coating with the antibacterial substances lysozyme, lactoferrin and immunoglobulins IgG, S-IgA and IgM and their ability to penetrate epithelial cells during infectious mononucleosis (IM) caused by Epstein-Barr virus. METHODS: Cellular samples were collected from the oropharynx of 21 patients (16 males, five females; age range 10-21 years) with current IM. An immunocytochemical assay using gold-labelled antiserum to human lysozyme, lactoferrin, IgG, S-IgA and IgM followed by gold particle and epithelial cell tracing in the transmission electron microscope. RESULTS: A significant reduction in bacterial coating with IgG (P<0.05) and S-IgA (P<0.01) was noted, whereas there was a significant increase in coating with lactoferrin (P<0.01) and IgM (P<0.01). No significant change in lysozyme coating of the bacteria was noted, compared with healthy controls. Bacterial penetration into epithelial cells was seen particularly in patients culture-positive for beta-haemolytic streptococci. CONCLUSIONS: Reduced bacterial coating with IgG and S-IgA immunoglobulins, combined with bacterial penetration into epithelial cells, may exacerbate the bacterial colonization on oropharyngeal mucosal membranes observed during IM.