Seventeen human clinical isolates representing four species of Desulfovibrio were characterized using 16S rRNA gene sequences and tests for catalase, indole, nitrate, bile, urease, formate-fumarate stimulation, desulfoviridin, motility, and hydrogen sulfide production, plus susceptibility to antimicrobial agents. Eighty additional strains representing 10 phenotypically similar genera (Bilophila, Selenomonas, Capnocytophaga, Campylobacter, Bacteroides, Sutterella, Anaerobiospirillum, Dialister, Veillonella, and Mobiluncus) were included for comparison. All Desulfovibrio species produced H 2 S and were desulfoviridin positive, and all Desulfovibrio species except D. piger were motile. The four Desulfovibrio species could be distinguished from each other using tests for catalase, indole, nitrate, urease, and growth on bile, with the following results ( Sulfate-reducing bacteria are a diverse group of organisms that include Desulfovibrio, Desulfomicrobium, Desulfobulbus, Desulfobacter, Desulfococcus, Desulfosarcina, Desulfobacterium, Desulfonema, Desulfotomaculum, and Thermodesulfobacterium. This group of organisms has a variety of morphologies, biochemical properties, and nutritional requirements. With the exception of Desulfovibrio spp., they are found only in the natural environment (4,30).Desulfovibrio is one of the first genera described and the most thoroughly studied genus among the sulfate-reducing bacteria (4, 5). These are sulfate-reducing, nonfermenting, anaerobic, gram-negative bacilli characterized by the presence of a pigment, desulfoviridin, which fluoresces red in alkaline pH and blue-green in acid pH under long-wavelength UV light (15,28) and by a strong sulfurous odor in broth media.Desulfovibrio spp. are ubiquitous, found in the environment, such as soil, water, and sewage, as well as in the digestive tracts of animals and humans (4,5,17,20,25,27,31). Two of the Desulfovibrio species, D. piger and D. fairfieldensis, have never been isolated from outside the human body and can be considered natural inhabitants of the intestinal tract, where sulfates abound (10,17,19). The organisms are usually recovered from mixed cultures and may cause human infections. They have been isolated from a variety of sources, such as brain

Tests of dalbavancin's in vitro activity against 209 aerobic and 120 anaerobic isolates from pretreatment diabetic foot infections showed an MIC 90 of <0.125 g/ml against methicillin-susceptible Staphylococcus aureus (MSSA), methicillin-resistant S. aureus (MRSA), and 120 anaerobes (Clostridium perfringens, other clostridia, Peptoniphilus asaccharolyticus, Finegoldia magna, and Anaerococcus prevotii), compared to respective MIC 90 s for MSSA and MRSA of 0.5 and 1 g/ml for vancomycin, 4 and 4 g/ml for linezolid, 0.5 and 0.5 g/ml for daptomycin, and 0.25 and >8 g/ml for clindamycin.Diabetes will affect ϳ14.5 million Americans by 2010 (8), and diabetic foot infections (DFIs) account for 20% of all hospitalizations of diabetic patients (1). DFIs are often multibacterial with aerobic and anaerobic bacteria. Recently, community-acquired methicillin-resistant Staphylococcus aureus (MRSA) (2,3,14) has accounted for 50% of all S. aureus skin and skin structure infection (SSTI) isolates (2,3,14). Previously, we noted (6) that MRSA was isolated from 20% of DFIs. As a reference lab for a DFI study, we received 473 pretreatment specimens, of which 91.3% grew aerobic bacteria, including 48% that grew S. aureus as one of the isolates (one-quarter of which were MRSA), and 41.6% grew anaerobes, with anaerobic gram-positive cocci the most common isolates.Dalbavancin (BI397) is new glycopeptide (4, 10) with good activity against gram-positive organisms, including MRSA, but none against gram-negative organisms (13,19). Dalbavancin has a long elimination half-life (ϳ8.5 days) and has been effective in treating gram-positive SSTIs (9, 18) with a two-dose regimen. For DFIs, an antimicrobial agent with a long half-life, especially one administered once weekly, seems to be advantageous.Specimens were obtained from patients with clinical infection who had not received antimicrobials within 48 h and after wound debridement. To avoid bias, 329 consecutively isolated gram-positive aerobic and anaerobic organisms were selected for this study. Isolates were identified by standard criteria (12, 15) and stored in skim milk at Ϫ70°C. Frozen anaerobic cultures were subcultured twice onto brucella agar supplemented with hemin, vitamin K 1 , and 5% sheep blood (Anaerobe Systems, Morgan Hill, CA) to ensure purity and good growth. Aerobic strains were subcultured to Trypticase soy blood agar. Susceptibility testing was performed according to CLSI (formerly NCCLS) standards M11-A6 (17) and M7-A6 (16).The types and numbers of strains tested are shown in Table 1. Laboratory-standard reference powders were either obtained from their manufacturers or purchased from Sigma Chemicals (St. Louis, MO).The MICs for anaerobes were determined by the agar dilution method using brucella agar supplemented with hemin, vitamin K 1 , and 5% laked sheep blood. Antimicrobial agents were reconstituted according to the manufacturers' instructions. Serial twofold dilutions of dalbavancin were prepared at 100-fold the final concentration in dimethyl sulfoxide on the day of t...

The bacterial division Synergistes represents a poorly characterized phylotype of which only a few isolates have been cultured, primarily from natural environments. Recent detection of Synergistes-like sequence types in periodontal pockets and caries lesions of humans prompted us to search the R. M. Alden culture collection (Santa Monica, Calif.) for biochemically unidentifiable, slow-growing, obligately anaerobic gram-negative bacilli. Here we report on five clinical isolates cultured from peritoneal fluid and two isolates from soft-tissue infections that together constitute three separate evolutionary lineages within the phylogenetic radiation of the division Synergistes. One of these clusters was formed by the peritoneal isolates and had an 85% similarity to Synergistes jonesii, the first described Synergistes species, which was isolated from the rumen of a goat. The isolates from soft-tissue infections, on the other hand, formed two distinct lineages moderately related to each other with a similarity of approximately 78%. In addition, by using a newly designed 16S rRNA gene-based PCR assay with intended target specificity for Synergistes, we found that the dominant phylotype from a fecal sample was nearly identical to that of the strains obtained from peritonitis. Conversely, sequence types detected in periodontal pockets formed a separate cluster that shared a similarity of only 80% with the soft-tissue isolates. These findings suggest a high diversity of medically important Synergistes clades that apparently are unique to individual ecological niches in the human body. In conclusion, we now have available the first characterized human isolates of the division Synergistes which are colonizing, and probably infecting, several sites in the human body.

Telavancin is a new semisynthetic glycopeptide anti-infective with multiple mechanisms of action, including inhibition of bacterial membrane phospholipid synthesis and inhibition of bacterial cell wall synthesis. We determined the in vitro activities of telavancin, vancomycin, daptomycin, linezolid, quinupristin-dalfopristin, imipenem, piperacillin-tazobactam, and ampicillin against 268 clinical isolates of anaerobic gram-positive organisms and 31 Corynebacterium strains using agar dilution methods according to National Committee for Clinical Laboratory Standards procedures. Plates with daptomycin were supplemented with Ca 2؉ to 50 mg/liter. The MICs at which 90% of isolates tested were inhibited (MIC 90 s) for telavancin and vancomycin were as follows: Actinomyces spp. (n ‫؍‬ 45), 0.25 and 1 g/ml, respectively; Clostridium difficile (n ‫؍‬ 14), 0.25 and 1 g/ml, respectively; Clostridium ramosum (n ‫؍‬ 16), 1 and 4 g/ml, respectively; Clostridium innocuum (n ‫؍‬ 15), 4 and 16 g/ml, respectively; Clostridium clostridioforme (n ‫؍‬ 15), 8 and 1 g/ml, respectively; Eubacterium group (n ‫؍‬ 33), 0.25 and 2 g/ml, respectively; Lactobacillus spp. (n ‫؍‬ 26), 0.5 and 4 g/ml, respectively; Propionibacterium spp. (n ‫؍‬ 34), 0.125 and 0.5 g/ml, respectively; Peptostreptococcus spp. (n ‫؍‬ 52), 0.125 and 0.5 g/ml, respectively; and Corynebacterium spp. (n ‫؍‬ 31), 0.03 and 0.5 g/ml, respectively. The activity of TD-6424 was similar to that of quinupristin-dalfopristin for most strains except C. clostridioforme and Lactobacillus casei, where quinupristin-dalfopristin was three-to fivefold more active. Daptomycin had decreased activity (MIC > 4 g/ml) against 14 strains of Actinomyces spp. and all C. ramosum, Eubacterium lentum, and Lactobacillus plantarum strains. Linezolid showed decreased activity (MIC > 4 g/ml) against C. ramosum, two strains of C. difficile, and 15 strains of Lactobacillus spp. Imipenem and piperacillin-tazobactam were active against >98% of strains. The MICs of ampicillin for eight Clostridium spp. and three strains of L. casei were >1 g/ml. The MIC 90 of TD-6424 for all strains tested was <2 g/ml. TD-6424 has potential for use against infections with gram-positive anaerobes and deserves further clinical evaluation.The development of resistance in gram-positive organismsincluding Staphylococcus aureus resistant to oxacillin and vancomycin (10,11,13) and linezolid (12) and vancomycinresistant enterococci also resistant to linezolid (4)-has accentuated the need for new antimicrobial agents. Telavancin is a novel glycopeptide that is bactericidal and shows concentration-dependent killing against gram-positive aerobes, including vancomycin-resistant strains (9). Unlike vancomycin, TD-6424 has multiple synergistic mechanisms of action resulting in TD-6424's enhanced activity against aerobic gram-positive species (5a, 9). At the MIC, it has exhibited postantibiotic effects of up to 6 h against S. aureus, compared to 2 h for vancomycin (9). TD-6424 is currently in phase 2 trials for serious gram-positive infe...

Against 443 aerobic and anaerobic bacteria isolated from diabetic foot infections, ceftobiprole MICs (g/ml) at which 90% of the isolates tested were inhibited were as follows: methicillin-resistant Staphylococcus aureus, 1; methicillin-susceptible S. aureus and Staphylococcus lugdunensis, 0.5; Anaerococcus prevotii, 0.125; Finegoldia magna, 0.5; Peptoniphilus asaccharolyticus, 1; Peptostreptococcus anaerobius, 4; Escherichia coli and Enterobacter species, 0.125; Klebsiella species, 2; and Pseudomonas aeruginosa, 8.Diabetic foot infections (DFIs) are common complications and account for ϳ20% of all hospitalizations for Ͼ18 million diabetics in the United States (1, 2). Early-stage DFIs are generally due to Staphylococcus aureus, and 20% of hospitalized DFI patients grow methicillin-resistant S. aureus (MRSA) (7); more-advanced DFIs involve aerobic gram-negative rods, and 45% also involve anaerobes (4.1 to 5.8 bacterial species isolated per specimen, composed of 2.9 to 3.5 aerobes and 1.2 to 2.6 anaerobes) (6 Ceftobiprole (BAL 9141) is a new broad-spectrum pyrrolidinone cephem antimicrobial active against S. aureus bacteria, including MRSA and vancomycin-intermediate S. aureus, vancomycin-resistant Enterococcus faecalis (but not ampicillin-resistant enterococci), other gram-positive organisms, and many gram-negative rods except Proteus vulgaris or extended-spectrum beta-lactamase (ESBL)-producing strains of Enterobacteriaceae (3,5,8,9,15), but data on its activity against anaerobes are limited (14).Consequently, we studied the activity of ceftobiprole against 443 aerobic and anaerobic strains isolated from pretreatment cultures (2001 to 2004) obtained after debridement from patients with symptomatic, complicated DFIs at 52 domestic clinical study sites and sent to our lab via overnight courier. All isolates (Table 1) were identified by standard criteria (10, 11). Standard antimicrobial laboratory powders were supplied by the manufacturers and reconstituted accordingly.Anaerobic susceptibility testing was performed by the agar dilution method according to CLSI standard M11-A6 (12) with a final inoculum of 10 5 CFU/spot. Plates were incubated at 37°C for 44 to 48 h in an anaerobic chamber (Anaerobe Systems, California). Aerobic isolates were subcultured onto Trypticase soy blood agar and tested by the broth microdilution method using cation-adjusted Mueller-Hinton broth, with lysed horse blood supplementation for streptococci and corynebacteria (4, 13). The trays were prepared in-house with serial twofold dilutions of the drugs by using the Quick-Spense apparatus (Sally Spring Instrument Co. Inc., Germantown, MD) and stored at Ϫ70°C until use. Colonies were suspended from overnight growth and added to the trays for a final inoculum of approximately 5 ϫ 10 5 CFU/ml. The trays were incubated for 18 to 24 h and examined.Results are presented in Table 1. The ceftobiprole quality control strain MICs were as follows: S. aureus ATCC 29213, 0.25 g/ml, seven times; 0.5 g/ml, twice; Escherichia coli ATCC 25922, 0.03 g/ml, onc...