Aerobic Cocci Research Articles

56th Annual Meeting of the American Academy of Implant Dentistry and the World Congress of Oral Implantology 7 Abstracts, 2007

56th Annual Meeting of the American Academy of Implant Dentistry and the World Congress of Oral Implantology 7 Abstracts, 2007

Efficacia di un collutorio e un dentifricio nella gestione della malattia parodontale. Studio clinico-microbiologico monocentrico

Objectives The aim of this work is to evaluate dedicated and adequate measures in addition to traditional professional and domiciliary oral hygiene methods, in order to maintain the periodontal health by the management of bacterial infection. Periodontal disease identifies in bacteria the “ primum movens” of its complex pathogenetic cascade. The control and detection of periodontal bacteria is essential in the treatment of patients affected by said disease. Materials Among 25 patients enrolled, 15 subjects were affected by periodontal disease and 10 were used as “control group”. For each patient, both the clinical indexes (PPD, CAL, PI, GI, BI) and the microbiological ones were monitored using traditional cultural methods and PCR. The results have been evaluated respectively after 2 weeks, 2 months and 4 months. In this study group, patients used both the mouthwash and the toothpaste for their domiciliary oral hygiene. Results and Conclusions Clinical indexes showed a substantial improvement in the study group. Aerobic cocci showed an higher sensibility to the proposed treatment as they are essential in the formation of the bacterial biofilm as the preamble of periodontal disease. Efficacy versus anaerobic bacteria such as P. gingivalis e F. nucleatum has been also noted.

Bacteriological implications in the pathogenesis of secondary aortoenteric fistulas.

Abstract The role of bacterial infection in the pathogenesis of aorto-enteric fistula was examined by a collective review of the clinical features and bacteriology in 213 patients. The most common presentation, gastrointestinal bleeding, occurred in 49 per cent of patients, although 32 per cent had systemic or local signs of infection as a presenting symptom. Results of intraoperative cultures were available in 115 patients, 33 of whom had two or more isolates. The predominant organisms were Escherichia coli, Staphylococcus aureus, group D Streptococcus and Bacteroides spp. The Gram-positive aerobic cocci predominated in fistulas developing within the first postoperative year which is compatible with a primary infection due to intraoperative contamination with skin flora. The Enterobacteriaceae and anaerobes showed no predilection for early or late occurring fistulas, suggesting that infection in these patients may be secondary to mechanical erosion of the graft through the adjacent duodenum. In either event, the likelihood that the aorto-enteric fistula is complicated by prosthetic infection should be seriously considered by the surgeon in planning the operative procedure.

Linezolid Contributed to Clostridium difficile Colitis with Fatal Outcome

Linezolid, the first of a new class of antibacterial drugs, the oxazolidinones, has inhibitory activity against a broad range of gram-positive aerobic cocci and also against certain anaerobes. Although diarrhea is one of the most frequently encountered adverse effects of linezolid, Clostridium difficile-related complications are very uncommon. One case of fatal C. difficile colitis in a patient with spondylodiscitis, who had received a long-term course of linezolid therapy, is presented. Colitis was able to be exclusively assigned to linezolid. Factors contributing to the colitis are discussed.

In vitro activity of LY333328 (oritavancin) against Gram-positive aerobic cocci and synergy with ciprofloxacin against enterococci.

Gram-positive cocci are a major cause of nosocomial bacteraemias and are often resistant to most antibiotics. The emergence of enterococci with reduced susceptibility to vancomycin has created an urgent need for novel antibiotics to combat infections associated with these bacteria. In this study the in vitro activity of LY333328 (oritavancin), a semi-synthetic glycopeptide, was evaluated. LY333328 was effective against all strains of staphylococci, streptococci and enterococci tested. A combination of LY333328 and ciprofloxacin was additive for 50% of Enterococcus faecium strains resistant to both vancomycin and ciprofloxacin, and for 100% of vancomycin-susceptible and either ciprofloxacin-susceptible or -resistant strains.

Infecção pulmonar por "Rhodococcus equi": relato dos dois primeiros casos brasileiros

O Rhodococcus equi, principal agente da rodococose, é um cocobacilo pleomórfico, gram-positivo e aeróbio, que infecta humanos por via inalatória ou transcutânea e se manifesta clinicamente como abscesso pulmonar. Relatam-se os dois primeiros casos brasileiros da doença. Ambos os pacientes eram imunocomprometidos e apresentavam quadro infeccioso pulmonar. O primeiro tinha AIDS e apresentava pneumonia cavitada em lobo superior esquerdo, que teve evolução fatal. O segundo tinha doença de Goodpasture, insuficiência renal crônica e fazia uso de corticosteróides. Apresentava uma lesão pulmonar escavada no lobo superior direito, que foi tratada com sulfametoxazol-trimetoprim, com resolução do processo.

In vitro Activity of Rifaximin, Metronidazole and Vancomycin against Clostridium difficile and the Rate of Selection of Spontaneously Resistant Mutants against Representative Anaerobic and Aerobic Bacteria, Including Ammonia-Producing Species

Background: Rifaximin is a rifamycin derivative characterized by a wide antibacterial activity. This drug is neither absorbed by the gastrointestinal tract nor inactivated by gastric juices, and exerts its action entirely within the intestinal lumen. Methods: In this study, the activity of this antibiotic was compared with that of metronidazole and vancomycin against 93 Clostridium difficile isolates. The rate of emergence of bacteria spontaneously resistant to the new compound was also evaluated in relation to representative gram-positive and gram-negative strains. In terms of MIC₅₀ values, rifaximin showed an intrinsic activity superior to that of the other agents. The emergence of spontaneously resistant strains was assessed with 46 aerobic (staphylococci, enterococci, Proteus spp., Citrobacter freundii, Providencia rettgeri, enteropathogenic, enteroinvasive, enterotoxigenic and entero- hemorrhagic Escherichia coli, and Salmonella enteritidis) and anaerobic (Clostridium spp., Bacteroides spp., Fusobacterium nucleatum and Peptococcus spp.) pathogens, most of them also ammonium producers. Two different methods, broth and agar dilution, were employed. Results: When liquid medium was employed, bacteria capable of sustained growth in 100 μg/ml of rifaximin were obtained after 2–5 transfers with gram-positive aerobic cocci, 2–3 transfers with gram-negative aerobic strains and 2–5 transfers with anaerobic species. At the highest dose used with the agar dilution method (8 × MIC), the frequency of emergence of spontaneously resistant mutants ranged from <1 × 10^–9 to 1.6 × 10^–8 with gram-positive aerobic and anaerobic cocci, while with aerobic and anaerobic gram-negative bacteria, this value ranged from <1 × 10^–9 to 1.7 × 10^–7. C. difficile showed a particularly low incidence of spontaneously resistant mutants (<1 × 10^–9). The low incidence of resistant subpopulations selected by levels of 8 × MIC of rifaximin suggests that the high levels of the drug which were reached in the gastrointestinal lumen may further prevent the selection of mutants. Conclusion: The low toxicity, broad antibacterial activity and very poor absorption from the gastrointestinal tract of rifaximin suggest a potential therapeutic use for this drug in gastrointestinal diseases, as well as in the management of patients with cirrhosis and chronic portal-systemic encephalopathy.

Effect of quinolones on intestinal ecology.

Quinolones have a selective effect on the normal human intestinal microflora. Published data on 13 different quinolone agents [ciprofloxacin, enoxacin, norfloxacin, ofloxacin, pefloxacin, lomefloxacin, levofloxacin, sparfloxacin, rufloxacin, sitafloxacin (DU-6859a), gatifloxacin, trovafloxacin and moxifloxacin] show that gram-negative aerobic bacteria, especially Enterobacteriaceae, are strongly suppressed or eliminated during therapy. Gram-positive aerobic cocci are affected strongly by administration of sitafloxacin and moxifloxacin and to minor degrees by the other quinolones. Three new quinolones--gatifloxacin, trovafloxacin and moxifloxacin--are very active against anaerobic bacteria in vitro but have minor effects on the anaerobic intestinal human microflora. Similar findings have been reported for the other 10 quinolones. Thus, the quinolone antibacterials have an ecological impact on the human intestinal microflora, mainly on the enterobacteria, that should be taken into account when these agents are used for prophylaxis or treatment of gastrointestinal bacterial infections.

Mucosal bacterial growth in the upper gastrointestinal tract in alcoholics (heavy drinkers).

Mucosal adherent bacterial flora in chronic alcoholics was studied and compared to a control group referred for upper endoscopy, mainly for dyspepsia. 22 alcoholics, admitted to hospital for detoxification, were examined using upper gastrointestinal endoscopy. Gastric and duodenal biopsies were taken for tissue pathology, quantitative and qualitative anaerobic and aerobic bacteriological culture and for culture of Helicobacter pylori (antral biopsies). 12 nonalcoholics, admitted for upper endoscopy mainly for dyspepsia, were chosen as a control group. Seven of these had used gastric acid inhibitors. Gastrointestinal symptoms were common among alcoholics: 20/22 (90%) had diarrhea, nausea and/or abdominal pain. There were signs of gastritis by endoscopy in 64% of the alcoholics and in 58% of the controls. Tissue pathology, however, showed active chronic antral gastritis in 27% of the alcoholics and in 42% of the controls. H. pylori were isolated in 7/22 of the alcoholics and in 4/12 of the controls, which corresponds to the mean prevalence for these age groups in Sweden. Significantly more bacteria, dominated by gram-positive aerobic cocci, were present in the gastric biopsies of alcoholics than in those of controls (mean of 2.9 x 10(6)/g material versus 4.4 x 10(5), p < 0.05). There were 2.6 times more bacteria in the duodenal biopsies of alcoholics than in those of the controls (p > 0.05, NS). Bacterial overgrowth (defined as >2 x 10(3) organisms/g material) was found in the stomach in 20/22 (90%) alcoholics and in 6/12 (50%) controls (p < 0.01). Alcoholics have an increased frequency of bacterial overgrowth in the upper gastrointestinal tract. This may contribute to the common gastrointestinal symptoms.

Über die Standortflora der menschlichen Bindehaut: Untersuchungen von 135 Personen unterschiedlichen Alters

Conjunctival flora is a prime suspect in searching for the cause of post-traumatic or post-operative ocular infections. Better information on its individual composition is therefore desirable. 135 persons (66 women, 69 men) were examined during a period of 1 1/2 years. The youngest patient was 3 years old, the oldest 90. Both eyes of all patients were examined. Megasphaera elsdenii, Bacteroides ureolyticus, Bacteroides pneumosintes, Stomatococcus mucilaginosus, and group ANF Corynebacterium were isolated for the first time in the eye by this study. The latter was found so often that it can be ascribed the role of an aerobic indicator organism. Characteristic changes appear in the conjunctival flora at different stages of life. In particular, for example, the species spectrum of aerobic bacteria broadens with advancing age, and the population of aerobic bacteria increases in density. With increasing age aerobic cocci are found less frequently in favor of the Corynebacteria. The proportion of anaerobic cocci increases among the anaerobes, while Propionibacteria are demonstrated less frequently. The significance of the organisms found in conjunctiva by this study for the first time is still unclear. No qualitative or quantitative sex-specific influence on the development of conjunctival flora was found.

In vitro antimicrobial activity of teicoplanin against gram-positive aerobic cocci

<I>In vitro</I> antimicrobial activity of teicoplanin against gram-positive aerobic cocci

27] Genetic systems in Staphylococci

The genus Staphylococcus consists of gram-positive, clump-forming, facultatively aerobic cocci and includes 20 distinct species. On the basis of reassociation kinetics, strains of the same species have 80–100% sequence identity, whereas different species never have more than 20%. Nevertheless, the various species have much in common—they can participate broadly in genetic exchange and they possess a single common pool of plasmids and transposons. Most of the available molecular and genetic data are for Staphylococcus aureus ; other species are increasingly being investigated at the molecular genetic level. The staphylococcal genome is fundamentally similar to other prokaryotic genomes, consisting of a single circular chromosome plus an assortment of variable accessory genetic elements (VGE) including prophages, plasmids, transposons, and other uncharacterized types.

Role of aerobic gram-negative rods, anaerobes, and fungi in wound infection after head and neck surgery: implications for antibiotic prophylaxis.

The prevention of wound infection after major contaminated head and neck surgery is a critical issue for the head and neck surgeon. The proper interpretation of cultures taken from wounds is uncertain. Multiple organisms are invariably isolated from this nonsterile site including indigenous aerobic and anaerobic flora, aerobic gram-negative rods, and fungi. We present evidence from controlled antibiotic trials that demonstrate the pathogenicity of oropharyngeal anaerobic flora. The presence of aerobic gram-negative rods and fungi generally represent colonization and antibiotic coverage need not routinely be directed at these organisms. On the other hand, the antibacterial spectrum of an agent used for head and neck would prophylaxis should include coverage for pathogenic oral flora, namely the gram-positive aerobic cocci (especially streptococci) and anaerobic bacteria.

Anaerobic bacteria in jaw cysts

The bacterial flora of the fluid content of 54 cysts of the jaws with a history suggestive of infection were studied. Forty-seven of these cysts were subsequently considered to be infected and from 78.6% of these, positive bacterial cultures were developed. Of the bacterial strains 89.2% were anaerobes and only 10.8% were pure aerobes or facultative anaerobes. Microorganisms isolated from each specimen ranged from 1 to 4 bacterial species. Gram positive anaerobic cocci revealed to be the most frequent bacterial group (36.9%), followed by Gram negative anaerobic rods (29.8%), Gram positive aerobic cocci being the third most common group of the isolates (19.0%). Antibiotic sensitivity tests of the isolated anaerobic cocci to a group of nine antibiotics revealed chloramphenicol and minocycline as the most effective. All anaerobic rods tested, were sensitive to metronidazole.

4-Quinolones in the treatment of infections of the central nervous system.

The literature concerning the penetration of new 4-quinolones into the cerebrospinal fluid (CSF) and brain tissue is reviewed as well as the few reports on clinical use of these antibiotics in the treatment of infections of the central nervous system (CNS). Pefloxacin has been found to penetrate well into the CSF of patients with normal or inflamed meninges as well as into brain tissue. Ciprofloxacin also penetrates into CSF, although not as well as pefloxacin. Two patients with meningitis due to Pseudomonas aeruginosa have been reported to have recovered after treatment with ciprofloxacin. Because of the spectrum limitations of quinolones, especially with regard to anaerobes and gram-positive aerobic cocci, these agents should not be considered for empiric use in CNS infections. They may, however, become alternatives in the rare cases of CNS infection caused by organisms resistant to other antibiotics.

Does the hygroscopic property of the laminaria tent imply a risk for ascending infection in legal abortions? A microbiological study.

In 53 women admitted for first-trimester abortion, the cervical canal was dilated with laminaria tents prior to vacuum aspiration. Before insertion of the tents, endocervical specimens were taken for microbiological investigations, including Chlamydia trachomatis, and both aerobic and anaerobic microorganisms. The laminaria tents, widened by their hygroscopic properties, were removed just before the vacuum aspiration and sent for cultivation of aerobic and anaerobic microorganisms. The Gram-positive aerobic cocci, Staph. epidermidis, Strept. faecalis and Strept. agalactiae as well as Escherichia coli and Klebsiella/Enterobacter were the most frequent microorganism among the aerobic isolates from the endocervices as well as from the laminaria tents. These microorganisms were identified on the tents in greater numbers than in the cervices. Staph. aureus was isolated from three laminaria tents, but only one of these 3 women was proved to be primarily colonized endocervically. Among the anaerobes, Bacteroidaceae followed by peptococci and peptostreptococci were the predominant genera found in the cervix as well as on the removed laminaria tents. These three groups of anaerobic microorganisms were found markedly less frequently on the laminaria tents than in the endocervix. On the other hand, Strept. intermedius, another anaerobe of possible enteric origin, was recovered from 9 laminaria tents but not in the cervices. Since no cases of clinically verified endometritis/salpingitis were registered in the present study it is concluded that the risk of a pelvic inflammatory disease (PID) due to the laminaria tent is negligible as long as the laminaria treatment does not exceed 24 hours.

Microbiology of the interdigital web

The microbiology of the interdigital toe areas is a complex subject that has been partially elucidated by the results of many investigations. Stable resident populations must be maintained in these moist and warm skin surfaces in order to prevent colonization of potential pathogens and overgrowth of innocuous residents. This balanced population of normal flora can be upset by conditions of increased hydration or prolonged occlusion. Population densities invariably increase as the moisture content of skin increases. 2,4,16 Fluorescent diphtheroids, nonlipophilic diphtheroids, and gram-negative bacilli preferentially flourish under such conditions. Concomitantly, hydrated skin also is macerated easily, and this predisposes individuals to develop superficial mycotic infections of the foot. 1,5 Stable resident populations thereby become affected by the diffusible antibiotic-like substances produced by dermatophytic fungi, 28–30 Resistant populations of aerobic cocci, nonlipophilic diphtheroids, and gram-negative bacilli become dominant over sensitive cocci and diphtheroids in such dermatophyte infections. Whereas the keratinolytic activity of dermatophytes was initially responsible for the pruritic, scaling lesions of mild athlete's foot, it is the proteolytic activity of brevibacteria and gram-negative bacilli that is responsible for the development of severe lesions. 5,32 Coincidently, large populations of such microorganisms generate copious amounts of metabolic by-products such as carbon dioxide and methanethiol, that are toxic to fungi.6'30 Dermatophytes thus become quite difficult to isolate in many cases of severe athlete's foot. 13,14,32 In such exacerbated intertriginous infections, treatment with drying agents and antibacterial substances is quite effective in alleviating symptomatology. 16,32 However, dermatophytes may persist or reinfect the interdigital web and thus maintain an asymptomatic form of chronic athlete's foot. In order to prevent further exacerbations, the interdigital web surfaces must be kept dry, and antimycotic therapy must be instituted to ultimately free the individual of the dermatophytic agent. Only under these circumstances will stable populations of resident normal flora and healthy interdigital web surfaces be maintained.

Anti-microbial activity of amniotic fluid β-lysin and the influence of zinc ion

SummaryAmniotic fluid β-lysin was found to have zinc-dependent bacteriostatic activity against the enteric bacilli, anaerobic Gram-negative bacilli and Gram-positive aerobic and anaerobic cocci. In contrast, β-lysin was found to exhibit bactericidal activity against the anaerobic and aerobic Gram-positive bacilli. This bactericidal activity was independent of zinc ion concentration. The clinical and biochemical implications of these observations are discussed.

Trimethoprim: mechanisms of action, antimicrobial activity, bacterial resistance, pharmacokinetics, adverse reactions, and therapeutic indications.

Trimethoprim has recently been marketed as a single-entity product for the treatment of initial episodes of uncomplicated symptomatic urinary tract infections; it was previously available only in combination with sulfamethoxazole. Trimethoprim exerts antimicrobial activity by blocking the reduction of dihydrofolate to tetrahydrofolate, the active form of folic acid, by susceptible organisms. It has inhibitory activity for most gram-positive aerobic cocci and some gram-negative aerobic bacilli. Resistance to trimethoprim may be either intrinsic or acquired. Acquired resistance most commonly stems from a chromosomal mutation that results in the production of a dihydrofolate reductase enzyme which is less vulnerable to trimethoprim inhibition. Gastrointestinal intolerance and skin eruptions are the most common untoward reactions resulting from the administration of trimethoprim. Trimethoprim constitutes very effective therapy for women with acute symptomatic urinary tract infections caused by E. coli, and the compound compares favorably with alternative standard agents, such as ampicillin and cephalexin. The safety of trimethoprim in the pregnant woman has not been established. Since indiscriminate use of trimethoprim could foster the emergence of trimethoprim resistance, thereby negating the value of both trimethoprim and trimethoprim-sulfamethoxazole, trimethoprim should only be prescribed for well defined indications. Trimethoprim is currently being investigated as definitive therapy for a wide range of infections, including bacterial exacerbations of chronic bronchitis, bacterial pneumonia, and typhoid fever. Initial reports are encouraging.

Characteristics and management of chronic destructive pneumonia.

In 12 years 627 patients presented to Wentworth Hospital, Natal with chronic destructive pneumonia (CDP). Common symptoms were haemoptysis, the production of foul-smelling sputum, and chest pain. The disease pursued a chronic course with acute exacerbations which may be lethal. The majority of patients were African men aged between 20 and 50 years who were free from other significant disease apart from dental infection. Radiographically and pathologically CDP had the characteristics of a necrotising pneumonia, and microbiological investigation showed mixed aerobic and anaerobic flora in the lower respiratory tract. Gram-positive aerobic cocci and Bacteroides species were the predominant organisms. In 120 patients treatment regimens were based on chloramphenicol, in 429 cephalosporins, and in 78 on combination therapy with cephalosporins, penicillin, and metronidazole. One hundred and seventy patients also required operative management in an attempt to control progress of the disease. The overall inpatient mortality rate from CDP was 7.8%. In the group of patients treated with combination therapy the mortality rate was 1.3%.