Antibacterial efficacy and drug-induced tooth discolouration of antibiotic combinations for endodontic regenerative procedures.

Elimination of microbial contamination from the root canal system is a precondition for successful root canal treatment. Teeth with immature root development, necrotic pulps and apical periodontitis present multiple challenges for successful treatment. Disinfection is achieved by irrigation followed by the placement of an intracanal medicament. A mixture of ciprofloxacin, metronidazole and minocycline (3-MIX S) has been shown to be very effective in eliminating endodontic pathogens in vitro and in vivo. Among the components of the mixture, minocycline can induce tooth discolouration after long-term oral use. Therefore, the elimination of minocycline from the above-mentioned combination has been suggested to prevent the occasion of this undesirable effect. The aim of this study was to investigate the potential antimicrobial efficacy of alternative antibiotic combinations [3-MIX C (clarithromycin); 3-MIX F (fosfomycin)] against bacteria from infected root canals. An additional objective was to evaluate their discolouration potential as possible alternatives to minocycline-based intracanal medicaments. Our in vitro results clearly demonstrated that 3-MIX C and 3-MIX F had a greater antimicrobial activity than 3-MIX S, underlying that clarithromycin still had a higher capacity to kill endodontic pathogens in vitro compared to fosfomycin. Both 3-MIX C and 3-MIX F were able to avoid the permanent staining effect of the crown.

Antimicrobial efficacy of cryotreatment against Enterococcus faecalis in root canals.

The purpose of this investigation was to evaluate intracanal bacterial reduction by cryotreatment using a dental instrument equipped with a duct and connected to a cryogenic fluid source. A total of 86 roots were infected with Enterococcus faecalis and incubated. After incubation, the contaminated roots were divided into three study groups: 35 roots irrigated with 2 ml of a 5% sodium hypochlorite (NaOCl) solution, 35 roots irrigated with 2 ml of a 5% NaOCl solution and further treated with cryo and 10 roots irrigated with 2 ml of saline solution, plus positive and negative controls. Subsequent to each irrigation treatment, the residual bacterial colonies were counted. The use of cryo-instrumentation in association with NaOCl irrigation significantly reduced the number of Ent. faecalis (P < 0·01) in the root canal compared with controls. The interesting potential of cryotreatment should be further investigated through clinical studies aimed to establish a correct irrigation protocol. Within the limits of the study, the cryotreatment seems to have a greater effect on the reduction in bacteria compared to a standard NaOCl irrigation.

Faecal microbiota in breast-fed infants after antibiotic therapy.

AIM: To evaluate modifications of gut microbiota after antibiotic therapy in breast-fed infants. STUDY DESIGN: Twenty-six exclusively breast-fed infants younger than 5 months hospitalized for pneumonia treated with ceftriaxone (50 mg per kilo per day administered intramuscularly) were recruited. Intestinal microbiota at day 0 - before starting antibiotic administration - at the end of the therapy (5 days after) and after 15 days after the stop was analysed. Stool samples were collected and immediately diluted and cultured on selective media to detect total bacteria, Enterobacteriaceae, enterococci and lactobacilli. Statistical analysis was performed by using Wilcoxon test. RESULTS: After 5 days of antibiotic therapy, we observed a significant reduction in total faecal bacterial count (p = 0.003) in Enterobacteriaceae (p = 0.001) and enterococci (p < 0.001), in comparison with day 0. After 5 days of therapy, lactobacilli are no longer detected. Conversely, bacterial count values for all bacteria detected after 15 days from the end of therapy are significantly increased and similar to day 0. CONCLUSION: Our findings showed that gut microbiota was significantly modified after 5 days of antibiotic therapy; exclusively, breast-feeding may be relevant in promoting the re-establishment of gut microbiota composition in early infancy.

A split-mouth study on microbiological profile in clinical healthy teeth and implants related to key inflammatory mediators.

This split-mouth study investigated the correlation of the qualitative and quantitative bacterial composition in dental plaque around clinically healthy periodontal and peri-implant subgingival sites with the levels of selected pro- and anti-inflammatory cytokines and the inflammatory infiltrate in the soft tissue surrounding a healthy dental implant and natural tooth in the same patient. Nine patients, all in good health and non-smokers, were studied. All of the patients were highly motivated in terms of oral hygiene and had healthy natural teeth and at least one healthy implant. After three sessions of professional oral care, clinical parameters were recorded. A sample of subgingival plaque was harvested with a sterile curette from the buccal side of the selected implants and teeth. The plaque samples were cultured to quantify the total microbiota and the number of obligate and facultative bacterial strains. Simultaneously, from the lingual/palatal aspect of the same implants and teeth the keratinized periodontal and peri-implant soft tissues were biopsied for cytokine expression and histomorphometric analysis. The tissue biopsies were halved: the real-time reverse transcriptase-polymerase chain reaction (PCR) was performed to detect active TNF-alpha, IL-1beta, IL-8, and TGF-beta2 and distribution, composition, quantification of inflammation were assessed in parallel. The patients harbored no periodontopathogens and the microbiological composition of the plaque taken from implant sites did not differ from that harvested from teeth. No significant differences were seen between implants and teeth for both proand anti-inflammatory cytokines. Even the histological examination showed no significant epithelial changes, although slight perivascular lymphocytic infiltration was seen in some biopsies.

The erythromycin-resistance in S. pyogenes does not limit the human polymorphonuclear cell antimicrobial activity.

In order to highlight the potential erythromycin immunomodulatory properties related to different antibiotic resistance patterns in Streptococcus spp., we evaluated the influence of the macrolide on the PMNs primary functions against erythromycin-susceptible (Ery-S) and erythromycin-resistant (Ery-R) S. pyogenes strains. A total of 438 S. pyogenes were isolated over the period 2005-2007. On the basis of the triple disk testing, 345 out of 438 S. pyogenes isolates were Ery-S and 93 were Ery-R; among the resistant strains, 65 displayed the cMLSB phenotype, 23 had the M phenotype and 5 had iMLSB phenotype. Concerning antibacterial activity of PMNs, our results showed that erythromycin did not modify bacterial uptake, but significantly increased the phagocyte intracellular killing, compared with controls, for both Ery-S and Ery-R strains. Consequently, this report underlines that in immunocompetent hosts the dichotomy between the in vitro resistance and clinical trial data for antimicrobial agents should be thoroughly re-evaluated.

Role of fosfomycin tromethamine in modulating non-specific defence mechanisms in chronic uremic patients towards ESBL-producing Escherichia coli.

Antimicrobial agents and polymorphonuclear cells (PMNs) have the potential to interact in such a way that improve the therapy for infectious diseases. In immunocompromised patients highly susceptible to microbial infections with high morbidity and mortality, several metabolic and functional alterations in PMNs, mostly related to microbicidal activity, are observed. Therefore, the antibiotic of choice should have a good antimicrobial effect without impairing host defences. The aim of this study is to evaluate in vitro effects of sub-inhibiting fosfomycin tromethamine (FT) concentrations on the primary functions of PMNs from healthy subjects and immunocompromised patients (haemodialysed and renal transplant recipients), against an ESBL-producing Escherichia coli, the most common aetiological agent in urinary tract infections (UTIs). FT is considered a first line drug in the eradication of UTIs due to its appropriate antimicrobial spectrum, oral bioavailability and minimal risk of microbial resistance. Our results provide evidence that FT is able to induce enhancement of the depressed phagocytic response of PMNs from patients on chronic haemodialysis and from renal transplant recipients, restoring their primary functions in vitro against ESBL-producing E. coli. All these data permit the conclusion that uremic-infected patients might additionally benefit from the immunomodulating properties of FT.

Tinea pedis and tinea unguium in a 7-year-old child.

This report documents tinea pedis and tinea unguium in a 7-year-old child. In all cultures Trichophyton rubrum was present. As tinea pedis and tinea unguium affect adults more often than children, they might be overlooked and misdiagnosed in the latter.

Improvement of clinical response in allergic rhinitis patients treated with an oral immunostimulating bacterial lysate: in vivo immunological effects.

Allergic rhinitis is known to be one of the most common chronic diseases in the industrialized world. According to the concept that allergic rhinitis patients generally suffer from an immune deficit, in order to stimulate specifically or aspecifically their immune system, immunomodulating agents from various sources, such as synthetic compounds, tissue extracts or a mixture of bacterial extracts, have been used. The aim of the present trial is to evaluate the efficacy of the treatment with an immunostimulating vaccine consisting of a polyvalent mechanical bacterial lysate (PMBL) in the prophylaxis of allergic rhinitis and subsequently to analyze its in vivo effects on immune responses. 41 allergic rhinitis patients were enrolled: 26 patients were randomly assigned to the group for PMBL sublingual treatment and 15 others to the group for placebo treatment. For all 26 patients blood samples were drawn just before (T0) and after 3 months of PMBL treatment (T3) to evaluate plasma IgE levels (total and allergen-specific) and the cytokine production involved in the allergic response (IL-4, IFN-gamma). The results of our study indicate that PMBL is effective in vivo in the reduction or in the elimination of the symptoms in rhinitis subjects during the treatment period in comparison to a non-immunostimulating treatment. A significant and clinically relevant improvement was found in 61.5%, a stationary clinical response was registered in 38.4% and no negative side effects associated with the medication or worsening were recorded. At the end of a 3-month follow up period the clinical picture remained the same as that observed at T3. PMBL treatment did not affect the serum IgE levels (either total or allergen-specific) and did not induce significant changes in IFN-gamma concentration. In contrast, PMBL therapy may be accompanied, in some patients, by a potential immunomodulating activity by decreasing IL-4 cytokine expression.

Improved phagocyte response by co-amoxiclav in renal transplant recipients.

BACKGROUND: Infectious diseases are a major source of morbidity and mortality for immunosuppressed transplant recipients and the antimicrobial chemotherapy can be often less effective in these individuals, because the contribution of underlying host defenses is absent. METHODS: The influence of co-amoxiclav on the functions of polymorphonuclear granulocytes (PMNs) from renal transplant recipients were investigated. RESULTS: PMNs from renal transplant recipients showed a diminished phagocytic activity with reduced phagocytosis and bactericidal activity against intracellular Klebsiella pneumoniae, compared to that seen with PMNs from healthy subjects. Co-amoxiclav significantly elicited the functions of PMNs from uremic patients, resulting in an increased percentage of ingested klebsiellae and in a higher bactericidal effect (98-99%), compared with the drug-free control system. When PMNs were collected from renal transplant recipients treated with co-amoxiclav a significant high increase in both phagocytosis and killing activity were detected, showing the co-amoxiclav capability of "restoring" even in vivo the depressed primary functions of PMNs. CONCLUSIONS: The interesting beneficial properties of co-amoxiclav, which result in restoring the phagocyte-dependent response in renal transplant patients both in vitro and in vivo, may make this drug more suitable for the treatment of infections in patients with defects of phagocyte functions.

Clarithromycin mediated the expression of polymorphonuclear granulocyte response against streptococcus pneumoniae strains with different patterns of susceptibility and resistance to penicillin and clarithromycin.

There is an urgent need for antibiotics that can be used in the therapy of infections caused by penicillin-resistant Streptococcus pneumoniae, the incidence of which is often associated with considerable morbidity and mortality. Antibiotics that can interact positively with the immune response and that also possess microbicidal properties might significantly contribute to improving the outcome of S. pneumoniae infections. Therefore, in the present study we investigated the effect of clarithromycin, an extended spectrum macrolide currently used in the treatment of respiratory tract infections, on the in vitro interaction between human polymorphonuclear granulocytes (PMN) and three strains of S. pneumoniae with different susceptibility or resistance patterns to both penicillin and clarithromycin. At a concentration of one-half the minimal inhibitory concentration (MIC), clarithromycin significantly enhanced human PMN functions, particularly intracellular bactericidal activity, against all the S. pneumoniae strains, including resistant ones. This finding may help to explain clarithromycin activity in vivo despite apparent resistance in vitro. Preexposure of PMNs to one-half the MIC of clarithromycin had no effect on either phagocytosis or intracellular killing, ruling out a direct antibiotic action on PMNs. Preexposure of streptococci to clarithromycin increased the susceptibility of S. pneumoniae to the bactericidal mechanisms of human PMNs compared with untreated bacteria, indicating that this macrolide may partly reduce bacterial virulence via changes in S. pneumoniae.

Antidermatophytic action of new 1-naphthylmethyl and benzo[b]thiophen-7-ylmethyl hydrazones related to inhibitors of squalene epoxidase.

Two series of hydrazonic compounds related to main classes of inhibitors of fungal squalene epoxidase (SE) were designed and prepared on the hypothesis of a pharmacophoric model. The antifungal activity of the new compounds was evaluated in vitro against dermatophytes, moulds and yeasts. Antidermatophytic activity resulted for several hydrazones, particularly for those containing a tett-butylacetylenic group, supporting the hypothesis that the introduction of a hydrazonic function in the model could retain the antimycotic activity.

In vitro compared activity of telithromycin and azithromycin against northwest Italian isolates of Streptococcus pyogenes and Streptococcus pneumoniae with different erythromycin susceptibility.

AIMS: This study compared the in vitro activity of telithromycin with that of azithromycin against 438 Streptococcus pyogenes and 198 Streptococcus pneumoniae, isolated over the period 2005-2007 from specimens of different human origin obtained in three Piemonte Region's hospitals. METHODS AND RESULTS: The determination of antimicrobial activity was evaluated by the microdilution broth method and the erythromycin-resistant (Ery-R) phenotypes by the triple-disc test. Exactly 78.8% of S. pyogenes and 69.2% of S. pneumoniae were erythromycin-susceptible (Ery-S). Concerning S. pyogenes, telithromycin was active against M and inducible MLS(B), subtype-C, phenotypes but not against constitutive MLS(B) strains. Telithromycin acted well against all S. pneumoniae, irrespective of their mechanism of macrolide-resistance. On the contrary, the Ery-R isolates, both S. pyogenes and S. pneumoniae, were resistant to azithromycin. CONCLUSIONS: Our results indicate that macrolide resistance in streptococci still persist in northwest Italy (21.2% of S. pyogenes and 308% of S. pneumoniae) and that telithromycin is confirmed as being extremely active even against recent clinical Ery-R streptococcal isolates. SIGNIFICANCE AND IMPACT OF THE STUDY: The present study emphasizes that an active surveillance of the phenotype distribution and antibacterial resistance in streptococci is essential in guiding the effective use of empirical treatment option for streptococcal infections, also at regional level.

Bacterial counts of intestinal Lactobacillus species in infants with colic.

Intestinal colonization by lactobacilli is suggested to be a prerequisite to normal mucosal immune functions. An inadequate level of lactobacilli may be involved in appearance of allergic disease of which, infantile colic, is often considered an early clinical manifestation. The aim of the study is to evaluate intestinal lactobacilli in breast-fed infants with infantile colic and healthy infants. Fifty-six breast-fed infants, aged 15-60 days were enrolled in the study and divided into two groups: colicky (30 cases) and healthy (26 cases) according to Wessel's criteria. Stool samples were collected, diluted and cultured on selective media. The colonies were counted, reported as colony forming unit (cfu) per gram of faeces and identified by biochemical methods. Different colonization patterns of lactobacilli were found among colicky and healthy infants. Lactobacillus brevis (4.34 x 10(8) cfu/g) and L. lactis lactis (2.51 x 10(7) cfu/g) were found only in colicky infants while L. acidophilus (2.41 x 10(7) cfu/g) was found only in healthy infants. Lactobacillus brevis and L. lactis lactis might be involved in the pathogenesis of infantile colic increasing meteorism and abdominal distension. Further studies are required to understand how the observed differences may be involved in the pathogenesis of this common disorder.

Intestinal microflora in breastfed colicky and non-colicky infants.

BACKGROUND: Infantile colics are a common problem in the first months of life. During this period, a process of intestinal colonization rapidly occurs. A difference in the gut microflora could play an important role in the pathogenesis of colics, changing the metabolism of carbohydrates and fatty acids. Actually, in the literature, only few data have been collected about this topic. In this study, we evaluated intestinal microflora in breastfed colicky and non-colicky infants. METHODS: Seventy-one breastfed infants, aged 3.2 +/- 0.6 wk, free from episodes of gastroenteritis and without previous assumption of antibiotic and probiotic drugs, were enrolled in the study. They were divided into two groups: colicky (42 cases) and non-colicky (29 cases), according to Wessel's criteria. Stool samples were collected, diluted and cultured on several selective media to detect lactobacilli, clostridia, gram-negative anaerobes and Enterobacteriaceae. Statistical analysis was performed using Student's t-test, chi2 test and a non-parametric test (Mann-Whitney U-test). RESULTS: Differences in gut microflora were found among colicky and non-colicky infants: colicky infants were less frequently colonized by Lactobacillus spp., and more frequently by anaerobic gram-negative bacteria. CONCLUSION: Our study indicates that colicky infants have different patterns of gut microflora. Further studies are required to understand whether gut microflora is the primary cause of colics or its consequence.

Influence of a new fluoroquinolone, AF3013 (the active metabolite of prulifloxacin), on macrophage functions against Klebsiella pneumoniae: an in vitro comparison with pefloxacin.

The efficacy of an antibiotic in the treatment of bacterial infections depends upon the interaction of bacterium, drug and phagocytes. In this study we have investigated the influence of AF3013, a new fluoroquinolone, on the activities of mouse peritoneal macrophages against Klebsiella pneumoniae, in comparison with the influence of pefloxacin. Bacterial susceptibility to phagocytosis and intracellular killing were determined after klebsiellae and macrophages had been incubated simultaneously with inhibitory concentrations of both AF3013 and pefloxacin and following pre-exposure of the microorganisms and the macrophages individually to the same concentrations of each drug. Under the experimental conditions used, both AF3013 and pefloxacin potentiated the phagocytic and microbicidal activities of the macrophages, although different mechanisms may be involved.