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We report two cases of tricuspid valve endocarditis with related organisms (Enterococcus faecalis and Gemella morbillorum), some months after colonic operation. This association, without preexistent valvular pathology and without any other classical aetiology of tricuspid endocarditis, has only exceptionally been described.
Several bacteria that are pathogenic to animals also infect plants. Mechanistic studies have proven that some human/animal pathogenic bacteria employ a similar subset of virulence determinants to elicit disease in animals, invertebrates and plants. Therefore, the results of plant infection studies are relevant to animal pathogenesis. This discovery has resulted in the development of convenient, cost-effective, and reliable plant infection models to study the molecular basis of infection by animal pathogens. Plant infection models provide a number of advantages in the study of animal pathogenesis. Using a plant model, mutations in animal pathogenic bacteria can easily be screened for putative virulence factors, a process which if done using existing animal infection models would be time-consuming and tedious. High-throughput screening of plants also provides the potential for unravelling the mechanisms by which plants resist animal pathogenic bacteria, and provides a means to discover novel therapeutic agents such as antibiotics and anti-infective compounds. In this review, we describe the developing technique of using plants as a model system to study Pseudomonas aeruginosa, Enterococcus faecalis and Staphylococcus aureus pathogenesis, and discuss ways to use this new technology against disease warfare and other types of bioterrorism.
Adrenal abscesses rarely occur in neonates and usually present with non-specific signs and symptoms. Prompt diagnosis requires an index of suspicion. We describe right-sided adrenal haemorrhage and abscess formation in a newborn with hypoxic-ischaemic encephalopathy following maternal post-partum haemorrhage and sepsis with Escherichia coli and Enterococcus faecalis. Percutaneous drainage of the abscess identified an E. coli isolate identical to that in the mother plus Candida albicans.
Multiple sclerosis is chronic demyelination disease associated with complex immunological disorders, resulting in increased susceptibility to different infections. A case of woman, aged 40 with multiple sclerosis who was admitted to the Internal Medicine Ward because of severe general state, fever of seven-day duration and systolic murmur in apex area is discussed in this paper. Clinical status and performed diagnostics, among others; echocardiography, blood cultures, abdominal ultrasonography, allowed to diagnose infective endocarditis caused by Enterococcus faecalis. Antibiotics as follows: augmentin, cefuroxim, cefotaxim and vancomycin were administered parenterally. As a result of the treatment normalization of temperature and complete recovery were obtained.
Alarming reports from various parts of the world of an increase in multiple-drug resistance among enterococci have prompted the Italian Association of Clinical Microbiologists to sponsor a nationwide study aimed at assessing the magnitude of this problem in Italy. During the last 3 months of 1988, technicians from a total of 162 general and teaching hospitals, in 16 of the 20 Italian regions and covering 89,061 beds, isolated 58,886 bacterial strains from inpatients and outpatients. Enterococci (4,879) represented 8.3% of all microorganisms identified, with Enterococcus faecalis accounting for 4,554 strains and Enterococcus faecium for the remaining 316 (6.5% of all enterococci analyzed). Enterococci were recovered most frequently from urine (62.5%) and genitourinary samples (13.7%). Only 58 strains (1.2%) were associated with bacteremia. The in vitro susceptibility of these organisms to 21 commonly used antibiotics is reported and compared with the susceptibility of isolates from a smaller epidemiologic study conducted in Italy in 1986 as well as with more recent findings from individual laboratories.
OBJECTIVES: To evaluate the potency of a novel peptide deformylase inhibitor, NVP PDF-713, against Gram-positive organisms having resistances to linezolid or quinupristin/dalfopristin. MATERIALS AND METHODS: A total of 45 strains from three genera (six species groups) were tested by reference broth microdilution methods. The mechanism of resistance to the oxazolidinone was determined by sequencing of the gene encoding the ribosomal target. RESULTS: NVP PDF-713 retained activity against linezolid-resistant staphylococci (MIC range 0.25-2 mg/L), Streptococcus oralis (MIC 0.5 mg/L), Enterococcus faecalis (MIC range 2-4 mg/L) and Enterococcus faecium (MIC range 0.5-4 mg/L). Quinupristin/dalfopristin-resistant E. faecium (MIC range 1-2 mg/L) and staphylococci (MIC range 0.12-2 mg/L) were also inhibited by NVP PDF-713. Many (10 of 13 strains) of the linezolid-resistant enterococci were resistant to vancomycin and these clinical strains had a G2576U ribosomal target mutation. CONCLUSIONS: NVP PDF-713 appears to be a promising clinical candidate among the peptide deformylase inhibitors for the treatment of infections caused by Gram-positive organisms that possess resistances to oxazolidinones or streptogramin combinations.
The increasing prevalence of vancomycin-resistant enterococcal (VRE) infections and the limited number of antimicrobial agents for their treatment emphasize a need for new, more effective agents. In this study, the in vitro activity of daptomycin was determined against a collection of 156 VRE from seven different institutions. Van types were characterized by PCR, and pulsed-field gel electrophoresis was performed to exclude isolates with >85% relatedness by dendrogram. Included were 126 Enterococcus faecium (109 vanA, 17 vanB) isolates, 5 Enterococcus faecalis (3 vanA, 2 vanB) isolates, 2 Enterococcus avium (vanA) isolates, 1 Enterococcus durans (vanA) isolate, 10 Enterococcus gallinarum (vanC1) isolates, and 12 Enterococcus casseliflavus (vanC2) isolates. MICs of daptomycin and five additional agents were determined by the NCCLS broth microdilution method with Mueller-Hinton (MH) broth containing supplemental calcium. MICs were also determined using two investigational E-test strip formulations, and disk diffusion testing was performed by the standard NCCLS method. The MIC of daptomycin at which 50% of the isolates tested were inhibited for this isolate collection was 4 microg/ml, and the MIC at which 90% of the isolates tested were inhibited was 8 microg/ml. Two isolates of vanA E. faecium were resistant to linezolid, and one isolate was resistant to quinupristin-dalfopristin. MICs of daptomycin determined by the E test with and without added calcium varied by 8- to 16-fold, and disk diffusion zones varied by 3 to 6 mm according to the calcium content of the commercial MH agar lots used in the study. This study has shown daptomycin to have good activity against a diverse collection of contemporary VRE isolates. However, improved standardization of the calcium content of MH agar will be important for reliable testing of daptomycin by clinical laboratories using either the E test or disk diffusion methods.
In a randomized crossover study, 12 volunteers (6 males, 6 females) received a single oral dose of 600 mg of linezolid or 500 mg of ciprofloxacin to assess the concentrations in plasma (up to 24 h), urinary excretion (by high-pressure liquid chromatography), and bactericidal titers in urine (UBT) at intervals up to 120 h. The mean maximum concentration of linezolid in plasma was 13.1 mg/liter, and that of ciprofloxacin was 2.46 mg/liter. The median cumulative levels of renal excretion of the administered dose of the parent drug were 44% for linezolid (range, 28 to 47%; mean +/- standard deviation, 40% +/- 7.8%) and 43% for ciprofloxacin (range, 20 to 56%; mean +/- standard deviation, 40% +/- 9.3%). The UBTs, i.e., the highest twofold dilution (with antibiotic-free urine used as the diluent) of urine that was still bactericidal, were determined for a reference strain and five gram-positive clinical uropathogens for which the MICs of linezolid and ciprofloxacin were as follows: Staphylococcus aureus ATCC 27278, 2 and 0.25 mg/liter, respectively; Staphylococcus aureus (methicillin susceptible), 1 and 16 mg/liter, respectively; Staphylococcus aureus (methicillin resistant), 2 and 64 mg/liter, respectively; Staphylococcus saprophyticus (methicillin susceptible), 1 and 0.25 mg/liter, respectively; Enterococcus faecalis, 2 and 1 mg/liter, respectively; and Enterococcus faecium, 2 and 1 mg/liter, respectively. The median UBTs of linezolid measured within the first 6 h were 1:96 for each of the two enterococcal strains and between 1:128 and 1:256 for the four staphylococcal strains. The median UBTs of ciprofloxacin were 1:64 for the two enterococcal strains; between 1:384 and 1:512 for the two ciprofloxacin-susceptible strains; and 1 (bactericidal activity of undiluted urine only) and 1:2 for the two resistant staphylococcal strains, respectively. The areas under the UBT-time curve (AUBT) for linezolid and ciprofloxacin showed no statistically significant (P<0.05) differences except for a better AUBT for linezolid for the two ciprofloxacin-resistant staphylococcal strains. For linezolid there were no statistically significant differences in UBTs or AUBTs for ciprofloxacin-susceptible and -resistant strains. Thus, the bactericidal activities of linezolid and ciprofloxacin against susceptible strains in urine were comparable, whereas linezolid also exhibited the same good bactericidal activity against ciprofloxacin-resistant strains. Therefore, linezolid should be tested for use as empirical treatment for complicated urinary tract infections due to gram-positive uropathogens in an appropriate clinical trial.
High-level resistance to aminoglycosides was observed in environmental isolates of enterococci. Various aquatic habitats, including agricultural runoff, creeks, rivers, wastewater, and wells, were analyzed. Strains of Enterococcus faecalis, E. faecium, E. gallinarum, and other Enterococcus spp. demonstrated multiple antibiotic resistance patterns to aminoglycosides.
Infective endocarditis is caused by bacterial colonization of the endocardium. Because endocardium modulates mechanical performance of subjacent myocardium, we studied acute effects of bacteria on isolated cardiac muscle and on the functional role of the endocardium. Bacteria, grown in broth at 37 degrees C, were added at increasing concentrations (10(2) to 10(6) bacteria/ml) to cat papillary muscles in Krebs-Ringer solution (1.25 mM Ca2+, 35 degrees C). The endocardial surface was damaged by exposing muscles to a stream of dry air for 30 s. Streptococcus (Enterococcus) faecalis induced significant increases in total peak isometric twitch tension (TT) and maximal velocity of unloaded shortening (Vmax) and significant decreases in time to TT (TtTT) and time to half isometric twitch tension decline (RT 1/2), both before and after removal of endocardial endothelium. This response could also be elicited with bacterial filtrate, after boiling the filtrate or after extracting the polysaccharides from it with KIO4. Increasing Ca2+ concentrations progressively reduced the response to the filtrate. Propranolol slightly, although not significantly, diminished the effects on TT and Vmax while abolishing the effects on TtTT and on RT 1/2. By contrast, Streptococcus bovis and Staphylococcus aureus did not affect TT or Vmax but induced a slight but significant decrease in TtTT at the highest concentration of bacteria. Accordingly, the filtrate of Strep. faecalis induces a positive inotropic effect. The active component is neither a protein nor a polysaccharide, and its effect may be partly beta-adrenoceptor mediated. Strep. bovis and Staph. aureus have negligible acute effects on contractility.
The purpose of this study was to evaluate the antibacterial efficacy of an intracanal medication composed of calcium hydroxide with 2% chlorhexidine. Dentin from 24 bovine incisors was used. The incisors were made into standardized cylindrical segments of dentin and infected with Enterococcus faecalis. They were then treated with an intracanal paste composed of calcium hydroxide and sterile water or an intracanal paste composed of calcium hydroxide and 2% chlorhexidine for 1 week. Dentin shavings were collected, suspended in solution, and spread on brain-heart infusion agar. After incubation, colony-forming units were enumerated. The amount of bacteria per mg of dentin was determined. The calcium hydroxide paste with 2% chlorhexidine was significantly more effective at killing E. faecalis in the dentinal tubules than calcium hydroxide with water.
Streptococcus pyogenes, S. equinus, S. bovis, S. salivarius, S. sanguis, S. mutans, S. rattus, S. cricetus, S. lactis, S. raffinolactis and Enterococcus faecalis have been characterized by oligonucleotide cataloguing of their 16S ribosomal RNA. All the organisms form a loose but coherent group that is phylogenetically equivalent to those of lactobacilli, bacilli, the Brochothrix and Listeria group, and related taxa that constitute one of several sublines within the 'Clostridium' branch of Gram-positive eubacteria. Within the Steptococcus-Enterococcus group, organisms fall into three moderately related clusters defined by Enterococcus, the lactic acid streptococci and streptococci of the pyogenic and oral groups, respectively.
The in vitro activity of the trinem sanfetrinem (formerly GV104326) (GV) was compared with that of vancomycin, ampicillin, and/or nafcillin against 287 gram-positive bacteria, including methicillin-resistant Staphylococcus aureus and multiresistant enterococci, by the agar and microbroth dilution methods. GV demonstrated 2 to 16 times more activity than ampicillin and nafcillin against the majority of these organisms. The MIC range of GV was 16 to 64 micrograms/ml for 19 Enterococcus faecium strains that were highly resistant to ampicillin (ampicillin MIC range, 64 to 512 micrograms/ml) and vancomycin resistant and 0.25 to 32 micrograms/ml for resistant Rhodococcus spp. Similar activities (+/-1 dilution) were observed by either the agar or the broth microdilution method. GV demonstrated bactericidal activity against a beta-lactamase-producing Enterococcus faecalis strain and against two methicillin-susceptible Staphylococcus aureus strains in 10(5)-CFU/ml inocula. Synergy between GV and gentamicin was observed against an E. faecalis strain that lacked high-level gentamicin resistance. The activity of GV suggests this compound warrants further study.
The CH3OH-CH2Cl2 extract of an Indian collection (entire plant) of Gynandropsis gynandra (L.) Briq. was separated based on bioassay results employing cancer cell lines. Six cancer cell growth inhibitors were isolated and found to be known flavone apegenin (4) and flavonols 1-3, 5, and 6. The structure of flavonol 2 was confirmed by X-ray crystal structure determination. All of the five flavonols (1-3, 5, 6) inhibited the murine P388 lymphocytic leukemia cell line with ED50 values of 3.0, 9.2, 4.0, 0.37, and 3.9 microg/ml, respectively. All six of the flavonoids (1-6) also exhibited activity against a panel of six human cancer cell lines. Penduletin (3) inhibited growth of the Gram-negative pathogen Neisseria gonorrhoeae and apegenin (4) inhibited growth of the Gram-positive opportunist Enterococcus faecalis.
Microflora of the pouch epithelium of 17 female koalas (Phascolarctos cinereus) were examined in relation to their current reproductive status and recent reproductive history. No microbial growth was observed in pouch swabs from 13 of 17 (76%) koalas, including four females without young, seven with pouch young and two with back young (i.e. permanently emerged from the pouch). Growth of bacteria or yeasts was observed in pouch swabs from four koalas, each of which had experienced mortality of its pouch young during the current breeding season. Seven species of microorganisms were isolated, including Pseudomonas aeruginosa, Serratia marcescens and Enterococcus faecalis. Based on the absence of microflora in the majority of females examined, we propose that the pouch epithelium normally provides a hostile environment for microbial colonization.
Synthesis of a number of 4,5,6,7-tetrahydro-thieno[3,2-c]pyridine substituted oxazolidinones have been reported. They have been screened against a panel of Gram-positive pathogens including methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecalis. A SAR has been developed. Compound 15 showed comparable activity (MIC) to linezolid and superior to eperezolid.
Amphibians respond to microbial infection through cellular and humoral defense mechanisms such as antimicrobial protein secretion. Most humoral defense proteins are synthetized in the skin. In this study we isolated two beta-galactoside-binding lectins with molecular weights of 50 and 56 KDa from the skin of Bufo arenarum. These lectins have significant hemagglutination activity against trypsinized rabbit erythrocytes, which was inhibited by galactose-containing saccharides. They are water-soluble and independent of the presence of calcium. The antimicrobial analysis for each lectin was performed. At mumolar concentration lectins show strong bacteriostatic activity against Gram negative bacteria (Escherichia coli K12 4100 and wild strains of Escherichia coli and Proteus morganii) and Gram positive bacteria (Enterococcus faecalis). The antibacterial activity of these lectins may provide an effective defense against invading microbes in the amphibian Bufo arenarum.
The application of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) to the analysis of blood serum leads to the observation of a large variety of reproducible mass spectral peaks corresponding to blood components. In this study, the use of MALDI-TOFMS was developed as a tool for monitoring immune response to bacterial infection. Employing the MALDI-TOFMS approach, the levels of many components of blood were found to be immune response independent whereas others were found to correlate directly with the response of the immune system to two known types of bacteria (Staphylococcus aureus and Enterococcus faecalis). The methodologies reported here should be useful for the rapid monitoring of blood, especially that of the immune response mechanisms in various animal species.