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. B. distasonis showed the highest rates of resistance to most of the ␤-lactams. B. fragilis, B. ovatus, and B. thetaiotaomicron showed significantly higher GM MICs and rates of resistance to clindamycin over time. The rate of resistance to moxifloxacin of B. vulgatus was very high (MIC range for the 8-year study period, 38% to 66%). B. fragilis, B. ovatus, and B. distasonis and other Bacteroides spp. exhibited significant increases in the rates of resistance to moxifloxacin over the 8 years. Resistance rates and GM MICs for tigecycline were low and stable during the 5-year period over which this agent was studied. All isolates were susceptible to chloramphenicol (MICs < 16 g/ml). In 2002, one isolate resistant to metronidazole (MIC ‫؍‬ 64 g/ml) was noted. These data indicate changes in susceptibility over time; surprisingly, some antimicrobial agents are more active now than they were 5 years ago.Pathogens of the Bacteroides fragilis group are the anaerobic pathogens that are the most frequently isolated from blood and abscesses. They are also among the most antibiotic-resistant isolates in anaerobic and mixed infections (21). Susceptibility to antibiotics varies considerably among the species of the group, yet most clinical laboratories do not routinely determine the species of the organism or test the susceptibilities of any anaerobic isolates, including those in the B. fragilis group, due to technical difficulties surrounding Bacteroides susceptibility testing (21). Consequently, the treatment of anaerobic infections is selected empirically, based on published reports on patterns of susceptibility (14,15,19,20). Therefore, the importance for reference laboratories to provide information on the patterns of susceptibility of the species within the group is important clinically. For over 20 years we have conducted a national survey on the susceptibility patterns of these important pathogens and our laboratory at Tufts New England Medical Center served as a reference center for the storage and testing of Bacteroides clinical isolates. We undertook this analysis to determine the susceptibility trends of the various species, using data from 1997 to 2004 for 5,225 isolates referred by 10 geographically diverse medical centers distributed throughout the United States. Bacterial isolates. Nonduplicate clinical isolates of the B. fragilis group were referred for susceptibility testing to the Special Studies Laboratory at New England Medical Center by ...

Among the variables identified as risk factors for SSI, only two have the possibility to be changed through interventions. Antibiotic prophylaxis would benefit all cesarean patients regardless of active labor or ruptured membranes and would decrease morbidity and length of stay. Women's healthcare professionals also must continue to encourage pregnant women to start prenatal visits early in the pregnancy and to maintain scheduled visits throughout the pregnancy to prevent perinatal complications, including postoperative infection.

The PNA FISH assay is rapid, accurate and reliable and in association with an AMT could decrease hospital length of stay in patients with CoNS bacteraemia in non-intensive care unit settings and prevent excessive vancomycin usage.

Hospital-acquired vancomycin-resistant enterococcal bacteremia has been associated with increased hospital costs, length of stay, and mortality. The peptide nucleic acid fluorescent in situ hybridization (PNA FISH) test for Enterococcus faecalis and other enterococci (EFOE) is a multicolor probe that differentiates E. faecalis from other enterococcal species within 3 h directly from blood cultures demonstrating gram-positive cocci in pairs and chains (GPCPC). A quasiexperimental study was performed over two consecutive years beginning in 2005 that identified GPCPC by conventional microbiological methods, and in 2006 PNA FISH was added with a treatment algorithm developed by the antimicrobial team (AMT). The primary outcome assessed was the time from blood culture draw to the implementation of effective antimicrobial therapy before and after PNA FISH. The severity of illness, patient location, and empirical antimicrobial therapy were measured. A total of 224 patients with hospital-acquired enterococcal bacteremia were evaluated, with 129 in the preintervention period and 95 in the PNA FISH period. PNA FISH identified E. faecalis 3 days earlier than conventional cultures (1.1 versus 4.1 days; P < 0.001). PNA FISH identified Enterococcus faecium a median 2.3 days earlier (1.1 versus 3.4 days; P < 0.001) and was associated with statistically significant reductions in the time to initiating effective therapy (1.3 versus 3.1 days; P < 0.001) and decreased 30-day mortality (26% versus 45%; P ‫؍‬ 0.04). The EFOE PNA FISH test in conjunction with an AMT treatment algorithm resulted in earlier initiation of appropriate empirical antimicrobial therapy for patients with hospital-acquired E. faecium bacteremia.Enterococcal bacteremia is the fourth most common cause of hospital-acquired bacteremia within the United States and the fifth most common in Europe according to the SENTRY antimicrobial surveillance program (2). The predominant enterococcal species that cause these infections are Enterococcus faecalis and Enterococcus faecium (28,38). Vancomycin-resistant enterococci (VRE) have emerged as a major problem and have progressively increased over the last decade. The most recent surveillance data from SENTRY showed that E. faecium resistance to vancomycin had increased from 40% to 61% in 2002, while the Surveillance and Control of Pathogens of Epidemiologic Importance survey also found 40% vancomycin-resistant E. faecium in 2002 (2, 38). At many tertiary-care medical centers, E. faecium is approaching nearly 100% vancomycin resistance (1,22,40). In contrast, E. faecalis has maintained susceptibility to ampicillin with a relatively small increase in vancomycin resistance (1, 37).

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