PubMed Health⌕ Search

Biomedical subjects

H S Sader

Publications and source records attributed to H S Sader.

At least 55 records · Page 3Linked to original sources
PubMed2000

Comparative evaluation of the in vitro activity of three combinations of beta-lactams with beta-lactamase inhibitors: piperacillin/tazobactam, ticarcillin/clavulanic acid and ampicillin/sulbactam.

Recently, two new combinations of Beta-lactam antibiotics with Beta-lactamase inhibitors became commercially available in Brazil: piperacillin/tazobactam and ampicillin/sulbactam. This study was designed to assess and compare the in-vitro activity of these new compounds, as well as that of ticarcillin/clavulanic acid, against bacteria isolated in our environment. A total of 749 bacteria isolated at São Paulo Hospital were tested using the disk diffusion method, in compliance with NCCLS standardization, using strict quality control. Only one sample per patient was included in the study. Oxacillin-resistant staphylococcus samples were not included in this study. Of the total samples tested, 84.5% were susceptible to piperacillin/tazobactam, 81.2% to ticarcillin/clavulanic acid, and 77.6% to ampicillin/sulbactam. Piperacillin/tazobactam was also found to be the most active combination of the three against Enterobacteriaceae ( n = 312), inhibiting 91.7% of the bacteria tested. Ticarcillin/clavulanic acid was active against 85.8% of the Enterobacteriaceae, while ampicillin/sulbactam inhibited 83.2% of the samples. This order of the spectrum of action (piperacillin/tazobactam > ticarcillin/clavulanic acid >ampicillin/sulbactam )was maintained for the majority of Enterobacteriaceae species analyzed. Pseudomonas aeruginosa ( n = 117) showed extremely high resistance to the three combinations. Piperacillin/tazobactam was active against 61.5% of the samples, while ticarcillin/clavulanic acid was active against 56.4% of the samples of this species. The activity of ampicillin/sulbactam against P. aeruginosa was extremely low; however, this was the most active combination against Acinetobacter baumannii ( 87.0% susceptibility). Piperacillin/tazobactam was the most active combination against Stenotrophomonas (Xanthomonas )maltophilia (100% susceptibility) and Burkholderia cepacia (90.9% susceptibility). The three combinations showed excellent activity against the Gram-positive cocci tested (97.3% to 98.2% susceptibility). In sum, piperacillin/tazobactam was more active against all Gram-negative species than the other two combinations, with the exception of A. baumannii, and showed similar activity against Gram-positive cocci.

Ampicillin↗
PubMed2000

Antimicrobial resistance in Brazil: comparison of results from two multicenter studies.

To evaluate whether our previous study of the antimicrobial resistance patterns in three centers in Brazil represented the pattern in the country as a whole, the results were compared to new data on 855 isolates from 20 clinical laboratories and 36 hospitals located in different regions of Brazil. Both multicenter studies showed high rates of antimicrobial resistance among Gram-negative bacilli isolated in Brazilian hospitals with the most important problems being: 1) E.coli and K.pneumoniae that produce ESBL; 2) Enterobacter spp. which likely express chromosomally mediated (AmpC) stably derepressed cephalosporinases producing resistance to third-generation cephalosporins and broad spectrum penicillins; 3) carbapenem resistance among Acinetobacter spp. and P.aeruginosa; and 4) fluoroquinolone and aminoglycoside resistance among many Gram-negative species. Our results emphasize the importance of regional antimicrobial resistance surveillance programs in guiding empirical therapy and for focusing intervention controls of antimicrobial resistance. Although the SENTRY Program has only three participating centers in Brazil, its results were validated by a larger Brazilian multicenter study.

Brazil↗
PubMed2000

In vitro antimicrobial activity of piperacillin/tazobactam in comparison with other broad-spectrum beta-lactams.

Combining tazobactam, a beta-lactamase inhibitor, with the ureidopenicillin, piperacillin, successfully restores the activity of piperacillin against beta-lactamase producing bacteria. Thus, piperacillin/tazobactam is highly active against most clinically important species of Gram-negative and Gram-positive bacteria, including anaerobes. We evaluated the in vitro activity of piperacillin/tazobactam against clinical isolates from a tertiary university hospital located in Sao Paulo, Brazil. Its activity was compared to that of ticarcillin/clavulanic acid, ampicillin/sulbactam, ceftazidime, ceftriaxone, cefotaxime, cefoxitin, aztreonam, and imipenem against 820 isolates (608 Gram-negative and 212 Gram-positive) collected from hospitalized patients in 1999. The most frequent species tested were Pseudomonas aeruginosa (168/20%), Escherichia coli (139/17%), Acinetobacter spp. (131/16%), and Staphylococcus aureus (76/9%). Of the isolates studied, 30% were from the bloodstream, 16% from the lower respiratory tract, and 11% from surgical wounds or soft tissue. The isolates were susceptibility tested by the broth microdilution method according to NCCLS procedures. The isolates tested were highly resistant to most antimicrobial agents evaluated. Imipenem resistance was not verified among Enterobacteriaceae, and piperacillin/tazobactam was the second most active beta-lactams against this group of bacteria (80.0% susceptibility). Extended-spectrum beta-lactamase production was very high among E. coli (approximately 20%) and Klebsiella pneumoniae (approximately 40%). Imipenem was uniformly active against these species (100% susceptibility) and piperacillin/tazobactam was the second most active compound inhibiting 84.4% of isolates. Pseudomonas aeruginosa was highly resistant to all beta-lactams evaluated and piperacillin/tazobactam was the most active compound against this species. Our results demonstrate an extremely high level of antimicrobial resistance in the hospital evaluated, especially among non-enteric Gram-negative bacilli. Due to this high level of resistance, piperacillin/tazobactam represents an important contribution to the treatment of nosocomial infections.

Bacteria↗
PubMed2000

Prevalence of antimicrobial resistance among respiratory tract isolates in Latin America: results from SENTRY antimicrobial surveillance program (1997-98).

One thousand seventy-three bacterial isolates were collected from patients with community acquired respiratory tract infections (CARTI) in 11 Latin American centers (7 countries) during 1997 and 1998. They were tested against numerous antimicrobial agents by the reference broth microdilution method as part of the ongoing multinational SENTRY Antimicrobial Surveillance Program. Among Streptococcus pneumoniae (553 isolates), approximately 61% were susceptible to penicillin. There was a great variation of the penicillin susceptibility rates among participating countries. The highest susceptibility rates were found in Argentina (76.7%) and Brazil (71.9%), while the lowest rate of penicillin susceptibility was detected in Mexico (33.3%). High level resistance to penicillin and resistance to cefotaxime were observed in nearly 10% of the isolates. The newer quinolones, levofloxacin (MIC(90) 2 microg/mL) and gatifloxacin (MIC90 0.5 microg/mL), were active against 100% of the isolates tested. Among the other non-beta-lactams drugs tested, the rank order of susceptibility against the pneumococci was: chloramphenicol (93.9%)>clindamycin (93.2%)> azithromycin (89.1%) > clarithromycin (88.7%)>tetracycline (78.5%)> trimethoprim/sulfamethoxazole (55.7%). The percentage of Haemophilus influenzae (361 isolates) isolates resistant to amoxicillin was 12. 7% (beta-lactamase positive). Among Moraxella catarrhalis (159 isolates) isolates, only 8.2% were susceptible. Clavulanic acid restored the activity of amoxicillin against both species. Trimethoprim/sulfamethoxazole was active against only 59.5% of H. influenzae, while susceptibility to this compound among M. catarrhalis was 96.1%. All other compounds tested were active against>95% of H. influenzae and M. catarrhalis isolates. These species were susceptible to levofloxacin (MIC90 < or = 0.5 microg/mL for both) and gatifloxacin (MIC90 < or = 0.03 microg/mL for both) with very low MICs. Our results indicate that penicillin resistance rates are particularly high among pneumococci in some countries. The newer fluoroquinolones show an excellent potency and spectrum against pathogens causing community acquired respiratory infections in Latin America.

Anti-Bacterial Agents↗
PubMed1999

Survey of blood stream infections attributable to gram-positive cocci: frequency of occurrence and antimicrobial susceptibility of isolates collected in 1997 in the United States, Canada, and Latin America from the SENTRY Antimicrobial Surveillance Program. SENTRY Participants Group.

The SENTRY Antimicrobial Surveillance Program was established in January, 1997 to monitor the predominant pathogens and antimicrobial resistance patterns of nosocomial and community-acquired infections via a network of sentinel hospitals in the United States (30 sites), Canada (eight sites), Latin America (10 sites), and Europe (24 sites). During the first 12-month study period (January to December, 1997), a total of 9519 blood stream infections (BSI) were reported by SENTRY participants in the U.S. (6150), Canada (1727), and Latin America (1642). The Gram-positive cocci, Staphylococcus aureus, coagulase-negative staphylococci (CoNS), enterococci, and streptococci accounted for 53.9% (5131 infections) of all BSI (56.5% U.S., 55.7% Canada, and 42.9% Latin America). The staphylococci, Enterococcus spp., S. pneumoniae, beta-hemolytic streptococci, and viridans group streptococci accounted for 6 of the top 11 BSI pathogens in the U.S. and Canada, whereas only S. aureus (1st), CoNS (3rd), and Enterococcus spp. (9th) were among the top 11 pathogens in Latin American hospitals. The results of this survey affirm the importance of Gram-positive cocci as causes of BSI in both North America and Latin America and demonstrate that important antimicrobial resistance exists among isolates of staphylococci, streptococci, and enterococci from all three geographic regions. This includes oxacillin-resistance among S. aureus (26.9% U.S., 29.2% Latin America, and 4.0% Canada) and CoNS (71.5% U.S., 68.4% Latin America, and 65.6% Canada), penicillin resistance among viridans group streptococci (48.5% U.S., 45.1% Canada, and 33.3% Latin America) and pneumococci (36.1% U.S., 27.5% Canada, and 65.6% Latin America), high-level resistance (HLR) to aminoglycosides among enterococci (27.2 to 70.1% U.S., 33.3 to 75.7% Canada and 16.7 to 51.5% Latin America), and macrolide resistance among beta-hemolytic streptococci (12.4 to 14.2% U.S., 10.5 to 12.3% Canada, and 0.0 to 4.0% Latin America), viridans group streptococci (32.4 to 39.7% U.S., 22.5-35.2% Canada, and 20.0% Latin America), and pneumococci (10.0 to 10.6% U.S., 9.8-10.8% Canada, and 9.4-18.7% Latin America). BSI isolates of Gram-positive cocci from the U.S. and Latin America were considerably more resistant than those from Canada. New agents with Gram-positive activity will be essential for optimal treatment of BSI attributable to Gram-positive cocci in both North and Latin America.

Anti-Bacterial Agents↗
PubMed1999

Antimicrobial susceptibility of coagulase-negative staphylococci and characterization of isolates with reduced susceptibility to glycopeptides.

The antimicrobial susceptibility of 239 coagulase-negative staphylococci (CNS) isolates consecutively collected from blood culture in patients admitted in a 600-bed teaching hospital was evaluated. The isolates were identified to the species level by conventional methods and the MicroScan Positive Combo Panel type 6 system, and their susceptibility to vancomycin, teicoplanin, and oxacillin were tested by agar dilution, disk diffusion, and MicroScan-WalkAway system. The species distribution was as follows: Staphylococcus epidermidis 120 (50.2%), S. hominis 29 (12.1%), S. haemolyticus 24 (10.0%), S. cohnii 14 (5.9%), and isolates from other CNS species 52 (21.8%). The percentage of resistance to oxacillin was 74.5% by agar dilution. The highest percentages of oxacillin resistance were found among S. haemolyticus (95.8%) and S. epidermidis (80.8%). Teicoplanin resistance (MIC > or = 32 micrograms/mL) was detected in five S. haemolyticus isolates, whereas intermediate resistance (MIC = 16 micrograms/mL) was detected in nine strains. These isolates with reduced susceptibility to teicoplanin were resistant to oxacillin, but remained susceptible to vancomycin (MIC < or = 4 micrograms/mL). Two isolates, one S. haemolyticus and one S. epidermidis, showed a vancomycin MIC of 8 micrograms/mL, and both MicroScan and disk diffusion methods classified these isolates as susceptible. Our results showed that glycopeptide resistance is emerging among CNS isolates in our institution and the disk diffusion method may not detect isolates with decreased susceptibility to these antimicrobial agents.

Adult↗
PubMed1999

International surveillance of blood stream infections due to Candida species in the European SENTRY Program: species distribution and antifungal susceptibility including the investigational triazole and echinocandin agents. SENTRY Participant Group (Europe).

The SENTRY Antimicrobial Surveillance Program, an international study of blood stream infections (BSIs), detected 170 episodes of candidemia in 20 European medical centers (13 nations) between January and December, 1997. Twenty-three percent of the candidal BSI occurred in patients hospitalized in an intensive care unit, 21% in patients in an internal medicine service, 13% in patients in a surgical service, and 9% in patients in an oncology service. Overall, 53% of the BSI were attributable to Candida albicans followed in prevalence by C. parapsilosis (21%), C. glabrata (12%), C. tropicalis (6%), C. famata (2%), C. krusei (1%), and C. inconspicua (1%). As observed previously in Canada and Latin America, C. parapsilosis and not C. glabrata, was the most common non-albicans species causing yeast BSI in Europe. The proportion of these candidemias attributable to C. albicans varied widely from 0-100% among the 20 European centers. Among the different species of Candida, resistance to fluconazole (MIC, > or = 64 micrograms/mL) and itraconazole (MIC, > or = 1.0 microgram/mL) was observed with C. glabrata and C. krusei and was observed more rarely among other species (e.g., C. inconspicua). Isolates of C. albicans, C. parapsilosis, C. tropicalis, and C. guilliermondii were all highly susceptible to both fluconazole and itraconazole. Furthermore, the investigational triazoles (BMS-207147, Sch 56592, and voriconazole) and an echinocandin (MK-0991) all demonstrated potent in vitro activity (MIC90s, 0.5, 0.5, 1.0, and 2.0 micrograms/mL, respectively) against these isolates. Continued surveillance at an international level will be important to monitor trends in species distribution and antifungal susceptibility among invasive strains of Candida.

Antifungal Agents↗
PubMed1999

Survey of bloodstream infections due to gram-negative bacilli: frequency of occurrence and antimicrobial susceptibility of isolates collected in the United States, Canada, and Latin America for the SENTRY Antimicrobial Surveillance Program, 1997.

During 1997, a total of 4,267 nosocomial and community-acquired bloodstream infections due to gram-negative organisms were reported from SENTRY hospitals in Canada (8 sites), the United States (30 sites), and Latin America (10 sites). Escherichia coli was the most common isolate (41% of all gram-negative isolates), followed by Klebsiella species (17.9%), Pseudomonas aeruginosa (10.6%), and Enterobacter species (9.4%). For all gram-negative isolates combined, the most active antimicrobials tested were meropenem, imipenem, and cefepime. The quinolones levofloxacin (MIC90, 2 microg/mL), ciprofloxacin (MIC90, 1 microg/mL), gatifloxacin (MIC90, 2 microg/mL), sparfloxacin (MIC90, 2 microg/mL), and trovafloxacin (MIC90, 2 microg/mL) were also active against most isolates. Bloodstream infection isolates from Latin America were uniformly more resistant to all classes of antimicrobial agents tested than were isolates from Canada or the United States. Resistance phenotypes consistent with extended-spectrum beta-lactamase production were also most common among E. coli and Klebsiella species from Latin America. Further investigation of the reasons for regional differences in resistance patterns is needed, as is ongoing surveillance to detect resistance trends and to guide antimicrobial use.

Bacteremia↗
PubMed1998

Antimicrobial susceptibility patterns for pathogens isolated from patients in Latin American medical centers with a diagnosis of pneumonia: analysis of results from the SENTRY Antimicrobial Surveillance Program (1997). SENTRY Latin America Study Group.

Pneumonia is the most common fatal hospital-acquired infection, with attributable mortality rates ranging from 30 to 60%. Rapid initiation of optimal antimicrobial therapy is essential for obtaining treatment success. In this report the antimicrobial susceptibility of 556 strains from the lower respiratory tract were collected by the SENTRY Antimicrobial Surveillance Program (1997). These strains were isolated from hospitalized patients with pneumonia in 10 Latin American centers (6 countries) as part of this 68-center worldwide program. The isolates were susceptibility tested against more than 70 drugs (35 reported) by the reference broth microdilution method. Klebsiella pneumoniae and Escherichia coli phenotypically consistent with extended spectrum beta-lactamase (ESBL) production were characterized further by ribotyping and pulsed-field gel electrophoresis. The five most frequently isolated species were (n/%): Pseudomonas aeruginosa (149/26.8%), Staphylococcus aureus (127/22.8%), Acinetobacter spp. (66/11.9%), Klebsiella spp. (56/10.1%), and Enterobacter spp. (40/7.2%). P. aeruginosa demonstrated high rates of resistance to a majority of the antimicrobial drugs tested. Carbapenems, amikacin, and piperacillin/tazobactam demonstrated the highest susceptibility rates (73.8-77.2%) against P. aeruginosa, however the lowest resistance rate was observed for cefepime (6.7%). Acinetobacter spp. also showed very high rates of resistance and the most active compounds were imipenem and meropenem (89.0% susceptibility) followed by the tetracyclines. Cephalosporin susceptibilities among Klebsiella spp. were low: cefoxitin, 73.0%; ceftazidime, 69.4%; and ceftriaxone, 65.9%. Approximately 37% and 28% of K. pneumoniae and E. coli isolates, respectively, were considered ESBL producers based on NCCLS criteria. Ceftriaxone was active against only 52.5% of Enterobacter spp. isolates, whereas cefepime was active against 90.0% of isolates (MIC50, < or = 0.12 microgram/mL). Oxacillin resistance was detected in nearly 50% of S. aureus isolates. The most active drugs against S. aureus were vancomycin, teicoplanin, and quinupristin/dalfopristin (MIC90, 1 microgram/mL). In summary, our study of pneumonias in Latin American medical centers demonstrated a greatly increased prevalence of Acinetobacter spp. and higher resistance rates among Gram-negative bacilli when compared with similar controlled studies from North America.

Anti-Bacterial Agents↗
PubMed1998

International surveillance of bloodstream infections due to Candida species: frequency of occurrence and antifungal susceptibilities of isolates collected in 1997 in the United States, Canada, and South America for the SENTRY Program. The SENTRY Participant Group.

An international program of surveillance of bloodstream infections (BSIs) in the United States, Canada, and South America between January and December 1997 detected 306 episodes of candidemia in 34 medical centers (22 in the United States, 6 in Canada, and 6 in South America). Eighty percent of the BSIs were nosocomial and 50% occurred in patients hospitalized in an intensive care unit. Overall, 53.3% of the BSIs were due to Candida albicans, 15.7% were due to C. parapsilosis, 15.0% were due to C. glabrata, 7.8% were due to C. tropicalis, 2.0% were due to C. krusei, 0.7% were due to C. guilliermondii, and 5.8% were due to Candida spp. However, the distribution of species varied markedly by country. In the United States, 43.8% of BSIs were due to non-C. albicans species. C. glabrata was the most common non-C. albicans species in the United States. The proportion of non-C. albicans BSIs was slightly higher in Canada (47.5%), where C. parapsilosis, not C. glabrata, was the most common non-C. albicans species. C. albicans accounted for 40.5% of all BSIs in South America, followed by C. parapsilosis (38.1%) and C. tropicalis (11.9%). Only one BSI due to C. glabrata was observed in South American hospitals. Among the different species of Candida, resistance to fluconazole (MIC, > or = 64 microg/ml) and itraconazole (MIC, > or = 1.0 microg/ml) was observed with C. glabrata and C. krusei and was observed more rarely among other species. Isolates of C. albicans, C. parapsilosis, C. tropicalis, and C. guilliermondii were all highly susceptible to both fluconazole (99.4 to 100% susceptibility) and itraconazole (95.8 to 100% susceptibility). In contrast, 8.7% of C. glabrata isolates (MIC at which 90% of isolates are inhibited [MIC90], 32 microg/ml) and 100% of C. krusei isolates were resistant to fluconazole, and 36.9% of C. glabrata isolates (MIC90, 2.0 microg/ml) and 66.6% of C. krusei isolates were resistant to itraconazole. Within each species there were no geographic differences in susceptibility to fluconazole or itraconazole.

Antifungal Agents↗
PubMed1997

Evaluation of the in vitro activity of cefepime compared to other broad-spectrum cephalosporins against clinical isolates from eighteen Brazilian hospitals by using the Etest.

The in vitro activity of cefepime was compared to that of ceftazidime, ceftriaxone, and cefotaxime in a multicenter study involving 10 clinical microbiology laboratories and clinical isolates from 18 Brazilian hospitals from 7 cities (4 states). A total of 982 isolates consecutively collected between December 1995 and March 1996 were susceptibility tested by using Etest and following the NCCLS procedures for agar diffusion tests. The cefepime spectrum was broader than that of the other broad-spectrum cephalosporins against both Gram-negative rods and Gram-positive cocci. Cefepime was particularly more active against Enterobacter sp. (MIC90, 2 micrograms/ml), Serratia sp. (MIC90, 2 micrograms/ml) and oxacillin-susceptible Staphylococcus aureus (MIC90, 3 micrograms/ml). Against Pseudomonas aeruginosa, cefepime (MIC90, 16 micrograms/ml) was slightly more active than ceftazidime (MIC90, 32 micrograms/ml) and 8- to 16-fold more active than ceftriaxone of cefotaxime (MIC90, > 256 micrograms/ml). Our results show that nosocomial bacteria, especially Gram-negative rods, have a high rate of cephalosporin resistance in Brazil. However, part of these resistant bacteria remains susceptible to cefepime. The Etest was shown to be an excellent method for multicenter studies of the in vitro evaluation of new antimicrobial agents.

Bacteria↗
PubMed1996

Use of macrorestriction analysis to demonstrate interhospital spread of multiresistant Acinetobacter baumannii in São Paulo, Brazil.

We evaluated the spread of Acinetobacter baumannii strains among three hospitals located in São Paulo, Brazil. A total of 46 isolates, which were typed by chromosomal DNA analysis with use of pulsed field gel electrophoresis (PFGE), were tested for susceptibility to the fluoroquinolones, carbapenems, aminoglycosides (amikacin), cephalosporins, polymyxin B, and ampicillin/sulbactam by means of the broth microdilution method, disk diffusion, and the E-test. Isolates with an identical PFGE pattern (pattern B) that were susceptible only to carbapenems, polymyxin B, and ampicillin/ sulbactam were recovered in all three hospitals. In addition, isolates with PFGE pattern A that were susceptible only to polymyxin B and ampicillin/sulbactam were recovered in hospitals 1 and 2. The results of our study strongly suggest the interhospital transmission of multiresistant epidemic strains of A. baumannii in São Paulo. Once in the hospital, these strains can disseminate and cause outbreaks with devastating consequences.

Acinetobacter↗
PubMed1996

In vitro activity of ampicillin-sulbactam against clinical multiresistant Acinetobacter baumannii isolates.

We evaluated the in vitro activity of ampicillin-sulbactam in comparison with that of broad-spectrum antimicrobial agents against Acinetobacter baumannii isolates. Two hundred and twelve clinical isolates collected between January 1993 and March 1995 from two tertiary hospitals located in São Paulo, Brazil were tested for susceptibility by the disk diffusion method against several broad-spectrum antimicrobial agents, including imipenem, ciprofloxacin, ceftazidime, aztreonam, amikacin, and polymyxin B. All strains were susceptible to polymyxin B. The second most active compound was the combination ampicillin-sulbactam (88% susceptibility). Only 79% of the isolates were susceptible to imipenem. Ciprofloxacin was active against 60 (28%) and amikacin against 34 (16%) isolates. Ceftazidime was the most active cephalosporin; however, only 9% of the isolates were susceptible to this compound. Both aztreonam and ampicillin alone showed very poor activity against this species (1% susceptibility). The prevalence of severe infections due to A. baumannii is increasing very rapidly in the tertiary hospitals of São Paulo and there are very few options for the treatment of these infections. Polymyxin B is invariably in vitro active against this species; however, this compound can cause severe side effects and is not commercially available for intravenous use in Brazil and in several other countries. Our results indicated that the combination ampicillin-sulbactam may be an alternative drug for the treatment of infections due to multiresistant A. baumannii; however, further studies are necessary to evaluate the clinical role of this compound for the treatment of severe infections.

Acinetobacter↗
PubMed1995

Emerging multiply resistant enterococci among clinical isolates. I. Prevalence data from 97 medical center surveillance study in the United States. Enterococcus Study Group.

To assess the evolving problem of therapeutic drug resistances among enterococci, we organized a comprehensive national (United States) surveillance trial using 99 recruited microbiology laboratories in 48 of the 49 contiguous states or districts. All but two sites completed the protocol that generated information from nearly 2000 enterococci, usually isolated from blood cultures. All strains were speciated by the same method (API 20S) and were susceptibility tested by three methods (broth microdilution, disk diffusion, and Etest) against ampicillin, penicillin, vancomycin, teicoplanin, gentamicin, and streptomycin. Strains resistant to a glycopeptide or penicillin, or possessing high-level aminoglycoside resistance were referred to the monitor's laboratory for validation and additional susceptibility testing against other alternative antimicrobial agents. The most common species were Enterococcus faecalis and Enterococcus faecium. However, antimicrobial resistance occurred most often among the E. faecium isolates. Twenty-three percent of participant centers (22 sites) reported 87 vancomycin-resistant isolates, which accounts for 4.4% of the isolates evaluated. A recent audit (March 1994) of the laboratories not reporting vancomycin resistance during the study interval (October-December 1992) revealed that 61% of sites have now recognized these strains, a threefold increase in 12-15 months. Teicoplanin remained active against 28% (Van B phenotype) of vancomycin-resistant enterococci (10 E. faecalis, 13 E. faecium, and one Enterococcus spp.). Ampicillin-resistant beta-lactamase-positive strains were found only at one medical center (two strains, 0.2% of referred or validated strains); however, ampicillin-resistant strains represented 12% of all enterococcal, but nearly 60% of E. faecium strains.(ABSTRACT TRUNCATED AT 250 WORDS)

Anti-Bacterial Agents↗
PubMed1995

Antimicrobial activity of 11 newer and investigational drugs tested against aerobic isolates from spontaneous bacterial peritonitis.

The in vitro susceptibility of 124 aerobic bacterial pathogens isolated from patients with spontaneous bacterial peritonitis (SBP) were tested against 11 antimicrobial agents, including parenteral or oral cephalosporins and fluoroquinolones. Most SBP isolates were Gram-negative organisms, and Escherichia coli and Klebsiella pneumoniae were responsible for 63% of the episodes evaluated. The fluoroquinolones (ciprofloxacin and ofloxacin) and the "fourth-generation" cephalosporin cefpirome were the most active agents against the Gram-negative bacteria. Commonly used cefotaxime and cefotaxime-desacetylcefotaxime (DES-CTX) combinations were also very active against Gram-negative bacteria with only few Enterobacter cloacae isolates being resistant (minimum inhibitory concentrations > 32 micrograms/ml). All streptococci were susceptible to cefotaxime, cefpirome, and cefdaloxime and to the cefotaxime-DES-CTX combinations, whereas only ofloxacin demonstrated acceptable activity against the enterococci. The widest spectrum of activity versus SBP isolates was found for ofloxacin (98% susceptibility) among the fluoroquinolones. For the beta-lactams, the widest spectrum of activity was demonstrated by cefpirome and the 2:1 cefotaxime-DES-CTX combination (93% susceptibility). These results indicate that the role of ofloxacin and newer parenteral or orally administered cephalosporins in the treatment of prophylaxis of SBP should be further evaluated.

Anti-Bacterial Agents↗
PubMed1995

Evaluation of Vitek and API 20S for species identification of enterococci.

The performance of the Vitek System and the API 20S for identifying enterococci to the species level was evaluated in comparison with a conventional reference test scheme. A total of 369 isolates originally derived from a sample from 97 medical centers were tested, and the percentage of correctly identified organisms was (Vitek/API): 97.6%/79.2%, 95.3%/91.2%, and 86.0%/20.7% for Enterococcus faecalis, Enterococcus faecium, and Enterococcus non-faecalis-non-faecium species, respectively. In addition, the predictive values for species identification of the results reported by the systems were 98.1% for Vitek and 85.9% for API. The Vitek System GPI card (software version > or = 8.1) was considered to be very acceptable for enterococci identification, with errors principally among the rare Enterococcus raffinosus isolates.

Bacteriological Techniques↗
PubMed1995

Relapse of catheter-related Flavobacterium meningosepticum bacteremia demonstrated by DNA macrorestriction analysis.

A 6-year-old boy with non-Hodgkin's lymphoma presented because of recurrent episodes (on 13 September 1993 and 12 January 1994) of possibly catheter-related bacteremia. The strains isolated during both episodes and seven epidemiologically unrelated control strains were typed by pulsed-field gel electrophoresis (PFGE) of chromosomal DNA. The similarity of the PFGE patterns of the two isolates suggests that both episodes of bacteremia were caused by the same strain. The antimicrobial susceptibility of the nine strains was tested against 32 antimicrobial agents. The antimicrobial susceptibility patterns of the two isolates from the referred case were identical and differed from those of other clinical isolates. The best in vitro activity (associated with 100% susceptibility) was demonstrated by ofloxacin, clinafloxacin, minocycline, and rifampin.

Bacteremia↗