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PubMed2006

Microbial colonization patterns predict the outcomes of surgical treatment of intrabony defects.

AIM: To explore the impact of bacterial load and microbial colonization patterns on the clinical outcomes of periodontal surgery at deep intrabony defects. MATERIALS AND METHODS: One hundred and twenty-two patients with advanced chronic periodontitis and at least one intrabony defect of >3 mm were recruited in 10 centres. Before recruitment, the infection control phase of periodontal therapy was completed. After surgical access and debridement, the regenerative material was applied in the test subjects, and omitted in the controls. At baseline and 1 year following the interventions, clinical attachment levels (CAL), pocket probing depths (PPD), recession (REC), full-mouth plaque scores and full-mouth bleeding scores were assessed. Microbial colonization of the defect-associated pocket was assessed using a DNA-DNA checkerboard analysis. RESULTS: Total bacterial load and counts of red complex bacteria were negatively associated with CAL gains 1 year following treatment. The probability of achieving above median CAL gains (>3 mm) was significantly decreased by higher total bacterial counts, higher red complex and T. forsythensis counts immediately before surgery. CONCLUSIONS: Presence of high bacterial load and specific periodontal pathogen complexes in deep periodontal pockets associated with intrabony defects had a significant negative impact on the 1 year outcome of surgical/regenerative treatment.

Alveolar Bone Loss↗

PubMed2004

Which is the best method to trace group A streptococci in sore throat patients: culture or GAS antigen test?

OBJECTIVE: To compare an antigen detection test (GAS antigen test) with the results from combinations of two various bacteriological test media in general practice patients with sore throat. Furthermore to assess the diagnostic properties of the chosen GAS antigen test and to compare semi-quantitative results of this test with the bacterial load found in the throat culture. SETTING: Two Norwegian general practices in Stokke and Kongsberg communities. SUBJECTS: 306 patients with sore throat lasting less than 7 days; 244 were adults, 62 were children under 10 years old, mean age 23.9 years (SD 15.0), 40% were men. MAIN OUTCOME MEASURES: Results from GAS antigen test, and distribution of bacteriological findings in throat cultures, compared with the results of our GAS antigen test; semi-quantitative results of the GAS antigen test compared with the bacterial load by culture. RESULTS: In the primary culture 110 patients harboured group A streptococci (GAS) infection, while the second culture identified another 17, giving a total of 127 patients. Some 33 patients harboured large-colony groups C and G. The GAS antigen test used had a sensitivity of 97% and specificity of 95% regarding GAS when compared with the two cultures. We found a significant correlation between the bacterial loads by culture and the semi-quantitative results of the GAS antigen test. CONCLUSIONS: By using a second, different set of bacteriological media, we identified an additional 17 patients with GAS infections. This raises the question of validity of frequently used reference standards in studies related to streptococcal infections. Compared with the combined results of the two throat cultures, the GAS antigen test used showed high sensitivity and specificity. Semi-quantitative evaluations of the rapid immunological test may also be of clinical value.

Adolescent↗

PubMed2003

Differential activation of the immune system by virulent Streptococcus pneumoniae strains determines recovery or death of the host.

Streptococcus pneumoniae infection may result in asymptomatic carriage, mucosal or invasive disease. We hypothesize that self-limiting or fatal disease outcome follows infection with S. pneumoniae differential activation of the host immune response. BALB/c and C57BL/6 mice were inoculated intranasally with S. pneumoniae serotype 3 strain WU2 and serotype 14 strain DW14 and mortality, bacterial load, pathological changes in the lungs and cytokines mRNA levels in the spleen were analysed. No differences between the C57BL/6 and the BALB/c inbred mice were observed except for the severity of their lung pathology and IL-4 expression. Infection of the two mouse strains with S. pneumoniae WU2 resulted in sepsis and death that occurred within 4 days post-inoculation. This death was preceded, in both mouse strains, in an increase over time of the lung bacterial load and bacteraemia. The lung pathology was characterized by diffuse pneumonia with marked congestion of the lungs. Analysis of mRNA expression of cytokines in the spleen revealed no alterations in tumour necrosis factor (TNF)-alpha, transforming growth factor (TGF)-beta, interleukin (IL)-12 and interferon (IFN)-gamma and induction of IL-10 and IL-4. The two strains of mice survived infection with S. pneumoniae DW14. This was accompanied by a reduction over time of lung bacterial load and bacteraemia. The lung pathology was characterized by focal lymphocyte infiltration and preserved architecture of the organ. Analysis of mRNA expression of cytokines in the spleen revealed a significant decrease in the levels of TNF-alpha, TGF-beta, IL-12 and IFN-gamma mRNA expression, which usually precedes cytokine protein expression. Interestingly, a significant increase in the levels of IL-4 mRNA expression was found in BALB/c mice only. This study suggests that differential activation or evasion of cytokine expression by S. pneumoniae virulent strains determines disease outcome regardless of the host's immunogenetic background.

Administration, Intranasal↗

PubMed2005

Evaluation of the relationship between smoking during pregnancy and subgingival microbiota.

BACKGROUND: Numerous studies have shown that smoking negatively affects periodontal health. Hormonal changes, which occur during pregnancy have also been reported to have adverse effects on the periodontal tissues or indirectly through alterations in the subgingival bacterial flora. At present, no knowledge exists concerning possible effects of smoking on the composition of subgingival plaque in pregnancy. The purpose of the present study was to evaluate the effects of smoking during pregnancy on the subgingival plaque bacteria most commonly associated with periodontal disease. METHODS: A total number of 181 women were examined within 72 h post-partum. Smoking status was recorded by means of a self-reported questionnaire and the study population was divided into three groups; non-smokers, light smokers, and heavy smokers. In each woman, two subgingival plaque samples were obtained from mesio- or disto-buccal aspect of randomly selected one molar and one incisor tooth by sterile paperpoints. Clinical periodontal recordings comprising presence of dental plaque, bleeding on probing (BOP), and probing pocket depth (PPD) were performed at six sites per each tooth at all teeth. Plaque samples were analysed by checkerboard DNA-DNA hybridization with respect to 12 bacterial species. In all analyses, the individual subject was the computational unit. Thus, mean values for all clinical parameters were calculated and bacterial scores from each individual sample were averaged. Statistical methods included chi2 test, Kruskal-Wallis test and Mann-Whitney U-test. RESULTS: Mean ages were similar in the study groups. Plaque, BOP and PPD recordings were lower in the heavy-smoker group, but the differences were not statistically significant (p>0.05). The detection rates and bacterial loads of the specific subgingival bacteria exhibited no significant differences between the groups. No correlation could be found between smoking status and detection rates and bacterial loads of various bacterial species. CONCLUSION: The present findings suggest that smoking during pregnancy does not have a significant effect on the composition of subgingival plaque bacteria.

Adolescent↗

PubMedDate not supplied

Methylene blue in the evaluation of gastrointestinal tract integrity: potential limitations.

INTRODUCTION: The integrity of the gastrointestinal tract can be evaluated by oral or rectal application of methylene blue. In the presence of anastomotic leaks or fistulas, methylene blue can be recovered in adjacent drains. However, parts of the dye can biochemically be reduced by intestinal bacteria to its colorless form leucomethylene blue, limiting the prediction of the test. MATERIALS AND METHODS: Diluted methylene blue was added to different concentrations of bacterial suspensions of Escherichia coli and Enterococcus faecalis. The time for discoloration of the suspension was measured. RESULTS: Reduction of methylene blue to leucomethylene blue was observed in both types of bacterial suspension. A 10(8) bacterial concentration discolorated the dye within 1 h in the E. faecalis suspension, respectively 2.5 h in the E. coli suspension. Longer bacterial interaction with methylene blue reduced the bacterial concentration required to achieve complete discoloration. DISCUSSION: Methylene blue can reliably be used as routine diagnostic test for the assessment of upper gastrointestinal integrity, where bacterial load is low. In the lower gastrointestinal tract, where bacterial load is generally higher, the dye can indicate leaks, only if extended intestinal passage after oral ingestion is avoided. In all other cases, the examiner has to be aware of false-negative results by bacterial discoloration of methylene blue.

Animals↗

PubMed2000

Febrile core temperature is essential for optimal host defense in bacterial peritonitis.

Fever, a nonspecific acute-phase response, has been associated with improved survival and shortened disease duration in infections, but the mechanisms of these beneficial responses are poorly understood. We previously reported that increasing core temperature of bacterial endotoxin (LPS)-challenged mice to the normal febrile range modified expression of tumor necrosis factor alpha (TNF-alpha), interleukin 1beta (IL-1beta), and IL-6, three cytokines critical to mounting an initial defense against microbial pathogens, but survival was not improved in the warmer animals. We speculated that our inability to show a survival benefit of optimized cytokine expression in the warmer animals reflected our use of LPS, a nonreplicating agonist, rather than an infection with viable pathogens. The objective of this study was to determine if increasing murine core temperature altered cytokine expression and improved survival in an experimental bacterial peritonitis model. We showed that housing mice at 35.5 degrees C rather than 23 degrees C increased core temperature from 36.5 to 37.5 degrees C to 39.2 to 39.7 degrees C, suppressed plasma TNF-alpha expression for the initial 48 h, delayed gamma interferon expression, improved survival, and reduced the bacterial load in mice infected with Klebsiella pneumoniae peritonitis. We showed that the reduced bacterial load was not caused by a direct effect on bacterial proliferation and probably reflected enhanced host defense. These data suggest that the increase in core temperature that occurs during bacterial infections is essential for optimal antimicrobial host defense.

Animals↗

PubMed2006

Comparison of floor sanitation methods.

Two methods for cleaning waxed polyvinylchloride and porcelain grès hospital room floors were compared in order to determine their decontamination capacity: dry wiping followed by damp washing, and damp washing followed by dry wiping. Dry wiping followed by damp washing did not produce any significant reduction in the average bacterial load. However, damp washing followed by dry wiping reduced the bacterial load for both types of flooring. The difference was statistically significant.

Colony Count, Microbial↗

PubMed2003

Orally administered CpG oligodeoxynucleotide induces production of CXC and CC chemokines in the gastric mucosa and suppresses bacterial colonization in a mouse model of Helicobacter pylori infection.

Bacterial DNA and unmethylated CpG oligodeoxynucleotides (CpG ODN) are known to be potent stimulators of the innate immune system in vitro and in vivo. We therefore investigated if oral administration of CpG ODN could enhance innate immunity in the gastric mucosa and control the extent of Helicobacter pylori infection in mice. Intragastric administration of a single dose of CpG ODN significantly increased local production of the CC chemokines macrophage inflammatory protein 1alpha (MIP-1alpha), MIP-1beta, and RANTES and the CXC chemokine gamma interferon-inducible protein 10 in the stomach and/or the small intestine. Importantly, intragastric administration of CpG ODN to mice with an already established H. pylori infection, in the absence of any coadministered antigen, was found to reduce the bacterial load in the stomach compared to the load in H. pylori-infected control mice, while similar administration of non-CpG ODN had no effect on the bacterial load. The reduction in the bacterial numbers in the stomachs of mice treated with CpG ODN was associated with enhanced infiltration of immune cells and increased RANTES production in the gastric mucosa compared to the infiltration of immune cells and RANTES production in H. pylori-infected control animals. These findings suggest that intragastric administration of CpG ODN without antigen codelivery may represent a valuable strategy for induction of innate immunity against H. pylori infection.

Administration, Oral↗

PubMed1975

Acedapsone (DADDS) treatment of leprosy patients in the Karimui of Papua New Guinea: status at six years.

Acedapsone (DADDS), a repository sulfone given by injection five times a year, has been used since 1967 for the treatment of all leprosy patients in the Karimui, an area of diffic-lt access. More than 460 patients have been treated, 336 beginning in November 1967 and continuing through the latest assessment 6 years later. The injections have been well received and they have been administered very regularly. Clinical observations were begun before 1967, as a base-line of assessments was available for the patients whose disease appeared before that time. The response to DADDS therapy has been satisfactory except in 5 of the 28 multibacillary patients in whose smears solid-staining Mycobacterium leprae have reappeared. M. leprae was isolated in mice from three of these patients; one strain has been proven to be completely susceptible to dapsone (DDS), and the other two very probably are. DDS levels in the plasma of these five patients were normal and well above the minimal inhibitory concentration. The most probable explanation is that a few viable M. leprae survived in the presence of inhibitory concentrations of DDS for the 4 to 6 years during which dead bacilli were disintegrating and disappearing from the tissues. The other 23 multibacillary patients responded satisfactorily. The decrease in the number of M. leprae in the skin smears has been most prompt in patients with low initial bacterial loads and in those with borderline lepromatous diagnoses. A high initial bacterial load and a fully lepromatous diagnosis were associated with a slow initial loss of M. leprae in the 1st year, followed by a more rapid loss the next year. All of the multibacillary patients have now been treated by the addition of a 90-day course of rifampicin.

Acetamides↗

PubMed1991

Reduction of salivary bacteria by pre-procedural rinses with chlorhexidine 0.12%.

The purpose of this study was to assess the effect of pre-procedural rinsing (2 consecutive rinses) with 0.12% chlorhexidine gluconate (CHX) on salivary bacteria during scaling and root planing procedures (S&RP). Because blood and debris arising from S&RP could inactivate CHX and decrease its antimicrobial effect, patients were evaluated throughout their appointment. Forty subjects rinsed with either 15 ml of CHX rinse or control (sterile water) for 30 seconds, expectorated and immediately rinsed again for 30 seconds. Unstimulated saliva samples were obtained at baseline (immediately before rinsing), and at 1 minute, 30 minutes, and 60 minutes after baseline. All 30 and 60 minute samples contained visible blood and debris. Samples were immediately diluted in transport fluid containing a CHX-neutralizer and then plated on trypticase soy agar for enumeration of the total aerobic and facultative bacterial load. The dual rinses with 0.12% CHX immediately reduced the salivary bacterial load 97% and this reduction persisted for 60 minutes during S&RP. At 30 minutes and at 60 minutes aerobic bacteria were reduced 77% compared to control, and 96% compared to baseline. CHX was not inactivated by the high organic load (blood and debris) present during the procedure. Pre-procedural rinsing with CHX has a profound and sustained effect on the aerobic and facultative flora of the oral cavity, which may contribute to a variety of clinical benefits. Pre-procedural rinsing may also be of value in protecting patients and dental professionals during dental manipulations.

Adult↗

PubMed1985

Cellular immune response to Mycobacterium bovis (BCG) in genetically-susceptible and resistant congenic mouse strains.

Congenic Bcgr (C.D2, resistant) and Bcgs (BALB/c, susceptible) mice were infected intravenously with Mycobacterium bovis (BCG, strain Montreal) in order to establish the relationship between different indicators of the cell-mediated immune response and the bacterial load attained in the host. There was a correlation between the bacterial burden and the splenomegaly response, granuloma formation in the liver and cross-protection against an heterologous pathogen (Listeria monocytogenes) in Bcgr and Bcgs mice. No relationship was found between bacterial load or granuloma formation and the development of specific acquired protection against an homologous organism (BCG or M. tuberculosis, H37Rv) as assessed by the level of resistance attained in BCG-primed mice challenged with virulent H37Rv or by the adoptive immunity conferred by BCG-primed spleen cells transferred to naïve irradiated recipients challenged with BCG.

Animals↗

PubMed2004

BisEDT and RIP act in synergy to prevent graft infections by resistant staphylococci.

Staphylococci are a major cause of infections associated with indwelling medical devices. Biofilm formation on these devices adds to the antibiotic resistance seen among clinical isolates. RNAIII-inhibiting peptide (RIP) is a heptapeptide that inhibits staphylococcal pathogenesis, including biofilm formation, by obstructing quorum sensing mechanisms. Bismuth ethanedithiol (BisEDT) also prevents biofilm formation at subinhibitory concentrations. RIP and BisEDT were combined to prevent infections in a rat graft model, using antibiotic sensitive and resistant strains of Staphylococcus aureus and Staphylococcus epidermidis. BisEDT, RIP, or rifampin, or their combinations reduced the graft associated bacterial load over seven days. BisEDT-RIP was the best combination, reducing bacterial load to undetectable levels. BisEDT-RIP may prove useful for coating medical devices to prevent staphylococcal infections.

Animals↗

PubMed1995

Antimicrobial activity of MDL 63,246, a new semisynthetic glycopeptide antibiotic.

MDL 63,246 is a semisynthetic derivative of the naturally occurring glycopeptide antibiotic MDL 62,476 (A40926). It was more active in vitro against Staphylococcus aureus and coagulase-negative staphylococci than MDL 62,476, teicoplanin, and vancomycin and was more active than mideplanin (MDL 62,873) against some isolates. MDL 63,246 had excellent activity against streptococci and teicoplanin-susceptible enterococci, and it also had in vitro activity against some VanA enterococcal isolates. It was more active than teicoplanin and vancomycin against acute staphylococcal, streptococcal, and enterococcal septicemia in immunocompetent and neutropenic mice. It was highly efficacious in reducing the bacterial load in the hearts of rats in staphylococcal endocarditis experiments and the bacterial load of Staphylococcus epidermis in a high infection model in neutropenic mice. The excellent in vivo activity of MDL 63,246 appears to correlate both with its in vitro antibacterial activity and with its long half-life in rodents.

Animals↗

PubMed2001

Evidence for superantigen involvement in severe group a streptococcal tissue infections.

Host-pathogen interactions were studied in tissue biopsy samples from patients with severe invasive group A streptococcus (GAS) infections. Skin, subcutaneous tissue, and fascia biopsy samples were divided into clinical grade 1 (no evidence of inflammation [n=7]) or clinical grade 2 (inflamed tissue--erythema and edema including cellulitis, fasciitis, and necrotizing fasciitis [n=24]). In situ imaging demonstrated significantly higher bacterial load in biopsy samples of higher clinical grade (P<.05), and the bacterial load correlated with the in vivo expression of the superantigen streptococcal pyrogenic exotoxin F (P<.02). Increased expression of the interleukin-1 cytokines and significantly higher expression of tumor necrosis factor-beta, interferon-gamma, and the homing receptors CC chemokine receptor 5, CD44, and cutaneous lymphocyte-associated antigen (P<.002-.05) were observed in biopsy samples of higher clinical grade. Thus, the cytokine profile at the local site of infection mimics that of a typical superantigen cytokine response. The findings of this study demonstrate a critical role for superantigens and Th1 cytokines in GAS tissue infections.

Bacterial Proteins↗

PubMed2003

Increased neutrophil influx but no impairment of protective immunity to tuberculosis in mice lacking the CD44 molecule.

Up-regulation of expression of the cell-surface marker CD44 is a major characteristic of T lymphocytes responding in the lungs of mice infected with Mycobacterium tuberculosis. These lymphocytes express an activated/memory phenotype as seen by their high expression of the CD44 molecule and low expression of CD62L and CD45RB cell-surface molecules. Based on increasing evidence that the CD44 molecule participates in several aspects of the inflammatory response, we evaluated its role in the response to infection with M. tuberculosis using gene-disrupted mice. In this report, we show that CD44 expression is not necessary for the proper trafficking of protective cells to the lungs of mice infected with M. tuberculosis or the direct expression of protective immunity leading to control and containment of the bacterial load in this organ. However, although there were no differences in the bacterial load or migration of activated T lymphocytes to the inflamed lung, the absence of the CD44 molecule resulted in a substantially increased accumulation of neutrophils in the lung. These data indicate that loss of CD44 expression does not alter expression of T helper cell type 1 immunity to tuberculosis in the lungs but has major effects on the overall cellular composition of the immunopathological response.

Animals↗

PubMed2006

Relationship between airway colonization, inflammation and exacerbation frequency in COPD.

RATIONALE: To evaluate bacterial colonization and the airway inflammatory response, and its relationship to the frequency of exacerbation in patients with stable chronic obstructive pulmonary disease (COPD). METHODS: Quantitative bacteriologic cultures, neutrophil elastase, myeloperoxidase (MPO), tumor necrosis factor alpha (TNF-alpha) and interleukin (IL)-8 were measured in bronchoalveoler lavage (BAL) in 39 patients with stable COPD [19 with frequent exacerbation (> or = 3/year), and 20 with infrequent] and in 18 healthy controls (10 smokers and 8 non-smokers). RESULTS: BAL revealed the microorganisms with potential pathogenicity above the established threshold (> or = 10(3)cfu/ml) in 68.4% of patients with frequent exacerbation, 55% of infrequent exacerbation, 40% of smokers and 12.5% of non-smokers controls (P=0.05). BAL MPO, IL-8 and TNF-alpha levels were found to be significantly higher in COPD as compared to controls (P=0.001). However, only IL-8 level was significantly higher in COPD patients with frequent exacerbation as compared to infrequent (P=0.001). Airway bacterial load correlated with levels of airway inflammation markers in COPD (P<0.05). CONCLUSION: The bacterial load and airway inflammation contributes to each other in stable COPD. However, there is a link only between interleukine (IL)-8 and frequent exacerbations. Clearly, the relationship between bacterial colonization, airway inflammation and frequent exacerbations is of major importance in understanding of the COPD pathogenesis.

Biomarkers↗

PubMed2004

Efficacy of dalbavancin against methicillin-resistant Staphylococcus aureus in the rat granuloma pouch infection model.

Infections due to methicillin-resistant Staphylococcus aureus (MRSA) are an important cause of morbidity and mortality in hospital patients. Moreover, increased incidences of outpatient MRSA have been recently reported. This study investigated the bactericidal activity of dalbavancin, a novel, semisynthetic glycopeptide antibiotic, against methicillin-sensitive S. aureus (MSSA) and MRSA in the rat granuloma pouch infection model. A single intravenous dose of 10 mg of dalbavancin/kg of body weight reduced the viable MRSA count in pouch exudates by more than 2 log CFU/ml, and regrowth was prevented for up to 120 h. Comparable results with vancomycin required four 100-mg/kg intramuscular doses. With one or two doses of vancomycin, the bacterial load declined over proportionately shorter periods of time, followed by regrowth. Reduction of the bacterial load obtained with 100- and 200-mg/kg oral doses of linezolid was relatively transient, with regrowth starting at 48 h. A single 10-mg/kg dose of dalbavancin reduced the MSSA count at 24 h to below the limit of detection, with no regrowth for at least 96 h. Dalbavancin demonstrated good exudate penetration; the ratio of the area under the curve (AUC) in plasma to the AUC in pouch exudate was 1.01. The in vivo activity of dalbavancin in this model is consistent with the antibiotic concentrations that are reached and maintained for extended periods of time after a single 10-mg/kg dose and with in vitro data showing that these concentrations are bactericidal for staphylococci. The pharmacokinetic and efficacy data seen in this relevant model of infection suggest that dalbavancin may be administered less frequently than vancomycin and linezolid.

Acetamides↗

PubMed2005

Wind, rain and bacteria: The effect of weather on the microbial composition of roof-harvested rainwater.

The microbiological and chemical quality of tank-stored rainwater is impacted directly by roof catchment and subsequent run-off contamination, via direct depositions by birds and small mammals, decay of accumulated organic debris, and atmospheric deposition of airborne micro-organisms and chemical pollutants. Previous literature reports on roof water quality have given little consideration to the relative significance of airborne micro-organisms. This study involved analyses of direct roof run-off at an urban housing development in Newcastle, on the east coast of Australia. A total of 77 samples were collected during 11 separate rainfall events, and microbial counts and mean concentrations of several ionic contaminants were matched to climatic data corresponding to each of the monitored events. Conditions both antecedent to, and those prevailing during each event, were examined to investigate the influence of certain meteorological parameters on the bacterial composition of the roof water and indirectly assess the relative contribution of airborne micro-organisms to the total bacterial load. Results indicated that airborne micro-organisms represented a significant contribution to the bacterial load of roof water at this site, and that the overall contaminant load was influenced by wind velocities, while the profile (composition) of the load varied with wind direction. The implications of these findings to the issues of tank water quality and health risk analysis, appropriate usage and system design are discussed.

Aerosols↗