Evaluation of the Activity of Eravacycline against a Broad Spectrum of Recent Clinical Anaerobic Isolates.

The novel fluorocycline antibiotic eravacycline is in development for use in the treatment of serious infections caused by susceptible and multidrug-resistant (MDR) aerobic and anaerobic Gram-negative and Gram-positive pathogens. Eravacycline and 11 comparator antibiotics were tested against recent anaerobic clinical isolates, including MDR spp. and Eravacycline was potent against all the isolates tested, including strains with tetracycline-specific resistance determinants and MDR anaerobic pathogens resistant to carbapenems and/or β-lactam-β-lactamase inhibitor combinations.

Trends in antimicrobial resistance among Bacteroides species and Parabacteroides species in the United States from 2010-2012 with comparison to 2008-2009.

The susceptibility trends for Bacteroides fragilis and related species against various antibiotics were determined using data from 3 years of surveillance (2010-2012) on 779 isolates referred by 7 medical centers. The antibiotic test panel included imipenem, ertapenem, meropenem, ampicillin-sulbactam, piperacillin-tazobactam, cefoxitin, clindamycin, moxifloxacin, tigecycline, linezolid, chloramphenicol and . MICs were determined using the agar dilution CLSI reference method.

Changes in the antibiotic susceptibility of anaerobic bacteria from 2007-2009 to 2010-2012 based on the CLSI methodology.

Antimicrobial susceptibility testing of anaerobic isolates was conducted at four independent sites from 2010 to 2012 and compared to results from three sites during the period of 2007-2009. This data comparison shows significant changes in antimicrobial resistance in some anaerobic groups. Therefore, we continue to recommend institutions regularly perform susceptibility testing when anaerobes are cultured from pertinent sites.

In Vitro Evaluation of the Activity of Imipenem-Relebactam against 451 Recent Clinical Isolates of Bacteroides Group and Related Species.

We evaluated the in vitro activity of imipenem-relebactam (imipenem-MK7655) against 451 recent clinical isolates within the Bacteroides group and related species. Relebactam did not enhance or inhibit the activity of imipenem against Bacteroides fragilis or other Bacteroides species. No synergistic or antagonistic effect was observed.

U.S.-Based National Sentinel Surveillance Study for the Epidemiology of Clostridium difficile-Associated Diarrheal Isolates and Their Susceptibility to Fidaxomicin.

In 2011 a surveillance study for the susceptibility to fidaxomicin and epidemiology of Clostridium difficile isolates in the United States was undertaken in seven geographically dispersed medical centers. This report encompasses baseline surveillance in 2011 and 2012 on 925 isolates. A convenience sample of C.

Activity of ceftolozane-tazobactam against a broad spectrum of recent clinical anaerobic isolates.

We evaluated in vitro activity of ceftolozane-tazobactam (TOL-TAZ), formerly CXA-201, against recent clinical anaerobic isolates with emphasis on the Bacteroides fragilis group. Ceftolozane-tazobactam showed good activity against B. fragilis species and intermediate to limited activity against other species of Bacteroides.

Activity of a novel cyclic lipopeptide, CB-183,315, against resistant Clostridium difficile and other Gram-positive aerobic and anaerobic intestinal pathogens.

We evaluated the activity of CB-183,315 against Clostridium difficile, including strains that are resistant to fluoroquinolones and metronidazole and with elevated MICs to vancomycin as well as other Gram-positive intestinal pathogens. The MICs of CB-183,315 against all C. difficile isolates were ≤ 1 μg/ml.

Update on resistance of Bacteroides fragilis group and related species with special attention to carbapenems 2006-2009.

The susceptibility trends for the species of the Bacteroides fragilis group against various antibiotics were determined using data from 4 years [2006-2009] on 1957 isolates referred by 8 medical centers participating in a National Survey for the Susceptibility of B. fragilis. The antibiotic test panel included doripenem, ertapenem, imipenem, meropenem, ampicillin:sulbactam, piperacillin:tazobactam, cefoxitin, clindamycin, moxifloxacin, tigecycline, chloramphenicol and metronidazole.

In vitro activity of ceftaroline against a broad spectrum of recent clinical anaerobic isolates.

The in vitro activity of ceftaroline was compared with those of ceftriaxone, clindamycin, imipenem, metronidazole, moxifloxacin, tigecycline, and vancomycin against 514 clinical anaerobic isolates using Clinical and Laboratory Standards Institute (CLSI) standard methodology. Ceftaroline demonstrated good to excellent activity against Gram-positive anaerobic pathogens and limited activity against Gram-negative pathogens, particularly Bacteroides fragilis group isolates.

Lessons learned from the anaerobe survey: historical perspective and review of the most recent data (2005-2007).

Background: The rationale and lessons learned through the evolution of the National Survey for the Susceptibility of Bacteroides fragilis Group from its initiation in 1981 through 2007 are reviewed here. The survey was conceived in 1980 to track emerging antimicrobial resistance in Bacteroides species.

Methods: Data from the last 11 years of the survey (1997-2007), including 6574 isolates from 13 medical centers, were analyzed for in vitro antimicrobial resistance to both frequently used and newly developed anti-anaerobic agents.

In vitro activities of doripenem, a new broad-spectrum carbapenem, against recently collected clinical anaerobic isolates, with emphasis on the Bacteroides fragilis group.

Doripenem was evaluated against 527 recent clinical isolates, i.e., 404 Bacteroides fragilis isolates and 123 gram-positive anaerobe isolates.

National survey on the susceptibility of Bacteroides fragilis group: report and analysis of trends in the United States from 1997 to 2004.

The susceptibility trends for the species of the Bacteroides fragilis group against various antibiotics from 1997 to 2004 were determined by using data for 5,225 isolates referred by 10 medical centers. The antibiotic test panel included ertapenem, imipenem, meropenem, ampicillin-sulbactam, piperacillin-tazobactam, cefoxitin, clindamycin, moxifloxacin, tigecycline, chloramphenicol, and metronidazole. From 1997 to 2004 there were decreases in the geometric mean (GM) MICs of imipenem, meropenem, piperacillin-tazobactam, and cefoxitin for many of the species within the group.

Evaluation of in vitro interaction of daptomycin with gentamicin or beta-lactam antibiotics against Staphylococcus aureus and Enterococci by FIC index and timed-kill curves.

The interactions of daptomycin with gentamicin and 5 beta-lactam agents were determined by checkerboard and timed-kill studies. Eighty isolates were tested by checkerboard: 20 each of methicillin-resistant Staphylococcus aureus (MRSA), methicillin-susceptible Staphylococcus aureus (MSSA), vancomycin-susceptible Enterococcus faecalis (VSEF) and vancomycin-resistant enterococci (VRE). Time kill curves were performed on 8 selected isolates: 2 each of MRSA, MSSA, VSEF and VRE.

Evaluation of the in vitro activity of NVP-LMB415 against clinical anaerobic isolates with emphasis on the Bacteroides fragilis group.

Objectives: To compare the in vitro activity of NVP-LMB415 (formerly referred to as NVP-PDF 713) with that of other agents with anti-anaerobe activity against clinical anaerobic isolates, with emphasis on the Bacteroides fragilis group.

Methods: The MICs for 405 B. fragilis group and 102 Gram-positive anaerobic isolates were determined using NCCLS-recommended procedures.

In vitro activities of tigecycline against the Bacteroides fragilis group.

The in vitro activities of tigecycline were tested against 831 isolates of the Bacteroides fragilis group representing all of the species within the group. On a weight-to-weight basis (8 microg/ml), tigecycline was more active than clindamycin, minocycline, trovafloxacin, and cefoxitin and less active than imipenem or piperacillin-tazobactam against all isolates of the B. fragilis group.

Emergence of fluoroquinolone resistance among Bacteroides species.

Background: Several newer generation fluoroquinolones have demonstrated good in vitro activity against Bacteroides species; particularly when first introduced. However, resistance of Bacteroides to quinolones appears to be increasing.

Materials And Methods: From 1994 to 2001, consecutive non-duplicated Bacteroides isolates from clinical specimens in 12 US hospitals were sent to the Tufts anaerobe laboratory for identification and susceptibility testing.

In vitro activities of newer quinolones against bacteroides group organisms.

The activities of BMS-284576, clinafloxacin, moxifloxacin, sitafloxacin, trovafloxacin, imipenem, cefoxitin, and clindamycin against 589 Bacteroides fragilis group isolates were determined. The activity of BMS-284576 was comparable to that of trovafloxacin. Sitafloxacin and clinafloxacin were the most active quinolones, and moxifloxacin was the least active.

National survey on the susceptibility of Bacteroides Fragilis Group: report and analysis of trends for 1997-2000.

The results of a multicenter US survey using the National Committee for Clinical Laboratory Standards currently recommended methodology for measuring in vitro susceptibility of 2673 isolates of Bacteroides fragilis group species were compared from 1997 to 2000. The test panel consisted of 14 antibiotics: 3 carbapenems, 3 beta-lactam-beta-lactamase inhibitors, 3 cephamycins, 2 fluoroquinolones, clindamycin, chloramphenicol, and metronidazole. Declines in the geometric mean minimum inhibitory concentrations were seen with imipenem, meropenem, ampicillin-sulbactam, and the cephamycins.

Comparative In vitro activities of daptomycin and vancomycin against resistant gram-positive pathogens.

The in vitro activity of daptomycin against 224 current gram-positive clinical isolates including vancomycin-resistant Enterococcus faecium (VREF), methicillin-resistant Staphylococcus aureus (MRSA), methicillin-resistant Staphylococcus spp. (MRSS), and penicillin-resistant Streptococcus pneumoniae (PRSP) was evaluated. The MICs at which 90% of isolates are inhibited for daptomycin and vancomycin, respectively, were as follows: MRSA, 1 and 2 microg/ml; MRSS, 1 and 4 microg/ml; PRSP, 1 and 0.

Comparative in vitro activities of clinafloxacin and trovafloxacin against 1,000 isolates of bacteroides fragilis group: effect of the medium on test results.

The in vitro antibacterial activities of clinafloxacin, trovafloxacin, ciprofloxacin, and cefoxitin against 1,000 clinical isolates of Bacteroides fragilis group were compared by agar dilution in brucella blood agar (BBA) and Wilkins Chalgren agar (WCA). Significantly higher geometric mean MICs for the three quinolones and cefoxitin (P<0.001) were obtained in BBA than in WCA.

Multicenter study of in vitro susceptibility of the Bacteroides fragilis group, 1995 to 1996, with comparison of resistance trends from 1990 to 1996.

Antimicrobial resistance, including plasmid-mediated resistance, among the species of the Bacteroides fragilis group is well documented. An analysis of the in vitro susceptibility of B. fragilis group species referred between 1995 and 1996 as well as during a 7-year (1990 to 1996), prospective, multicenter survey of over 4,000 clinical isolates of B.

In vitro and in vivo antibacterial activities of a novel glycylcycline, the 9-t-butylglycylamido derivative of minocycline (GAR-936).

The 9-t-butylglycylamido derivative of minocycline (TBG-MINO) is a recently synthesized member of a novel group of antibiotics, the glycylcyclines. This new derivative, like the first glycylcyclines, the N,N-dimethylglycylamido derivative of minocycline and 6-demethyl-6-deoxytetracycline, possesses activity against bacterial isolates containing the two major determinants responsible for tetracycline resistance: ribosomal protection and active efflux. The in vitro activities of TBG-MINO and the comparative agents were evaluated against strains with characterized tetracycline resistance as well as a spectrum of recent clinical aerobic and anaerobic gram-positive and gram-negative bacteria.

In vivo activities of peptidic prodrugs of novel aminomethyl tetrahydrofuranyl-1 beta-methylcarbapenems.

A series of novel aminomethyl tetrahydrofuranyl (THF)-1 beta-methylcarbapenems which have excellent broad-spectrum antibacterial activities exhibit modest efficacies against acute lethal infections (3.8 mg/kg of body weight against Escherichia coli and 0.9 mg/kg against Staphylococcus aureus) in mice when they are administered orally.

In vitro activities of aminomethyl-substituted analogs of novel tetrahydrofuranyl carbapenems.

CL 188,624, CL 190,294, and CL 191,121 are novel aminomethyl tetrahydrofuranyl (THF)-1 beta-methylcarbapenems. The in vitro antibacterial activities of these THF carbapenems were evaluated and compared with those of biapenem, imipenem, and meropenem against 554 recent clinical isolates obtained from geographically distinct medical centers across North America. The antibacterial activities of the THF carbapenems were equivalent to that of biapenem, and the THF carbapenems were slightly more active than imipenem and less active than meropenem against most of the members of the family Enterobacteriaceae but lacked significant activity against Pseudomonas isolates.

In vitro activity of piperacillin/tazobactam against isolates from patients enrolled in clinical trials.

The in vitro activity of piperacillin alone or titrated with a constant concentration of 4 mug/ml tazobactam was evaluated against 3962 baseline pathogens isolated from 1899 patients enrolled in 9 clinical trial studies in North America. Tazobactam increased susceptibility rates of piperacillin for Enterobacteriaceae from 81% to 96%, Staphylococcus (methicillin susceptible) spp. from 6% to 100%, Bacteroides fragilis group from 79% to >99% and Haemophilus from 85% to 98%.