Urinary tract infection trends in Latin American hospitals: report from the SENTRY antimicrobial surveillance program (1997-2000)

Urinary tract infections (UTI) are one of the most common infectious diseases diagnosed in outpatients as well as in hospitalized patients. The objective of this study was to report the frequency of occurrence and antimicrobial susceptibility of uropathogens collected in Latin America between 1997 to 2000 through the SENTRY Antimicrobial Surveillance Program. Antimicrobial susceptibility testing was performed and results interpreted using reference broth microdilution methods. In the 4 year period, a total of 1961 urine isolates from hospitalized patients were included. The patients' mean age was 51.3 years and most of the infections occurred among women (65.6%). Esherichia coli was the most frequent pathogen isolated followed by Klebsiella spp., Pseudomonas aeruginosa, and Proteus mirabilis. Among the E. coli isolates, piperacillin/tazobactam, aztreonam, extended-spectrum cephalosporins, carbapenems and amikacin constitute reasonable therapeutic options for treatment of serious UTI in Latin America (91.0-100.0% susceptible). High resistance rates to fluoroquinolones (17.5-18.9%) and trimethoprim/sulfamethoxazole (>45.0%) were observed among the E. coli. In contrast, nitrofurantoin displayed susceptibility rate of > 87.0%. Against Klebsiella spp. infections, the only effective therapeutic option would be the carbapenems due to the high number of isolates (>30.0%) producing extended-spectrum beta-lactamases (ESBL). Even the new fluoroquinolones showed limited activity against Klebsiella spp. (72.1-88.6% susceptible) and the P. aeruginosa isolates showed high resistance rates to most antimicrobial agents tested. The results of this survey endorse the importance of Enterobacteriaceae as cause of UTI in Latin America. Our results also demonstrate that the uropathogens isolated in the Latin American medical centers exhibit high resistance to various classes of antimicrobial agents. Carbapenem-resistant P. aeruginosa, ciprofloxacin-resistant E. coli, ESBL-producing K. pneumoniae constitute serious problem in this geographic region.     

Susceptibility patterns of orally administered antimicrobials among urinary tract infection pathogens from hospitalized patients in North America: comparison report to Europe and Latin America. Results from the SENTRY Antimicrobial Surveillance Program (2000)

Urinary tract infections (UTIs) remain a worldwide nosocomial infection problem. Geographic variations in pathogen occurrence and susceptibility profiles require monitoring to provide information to guide new (garenoxacin [BMS284756]) therapeutic options. Two thousand seven hundred-eighty UTI isolates from Europe (n = 783), Latin America (531), and North America (1,466) were tested and compared against 44 agents by reference methods in the SENTRY Antimicrobial Surveillance Program. The top seven pathogens accounted for 90% of all isolates and the rank order for all regions was: Escherichia coli (1,316; 47%), Enterococcus spp. (351; 13%), Klebsiella spp. (306; 11%), Pseudomonas aeruginosa (210; 8%), Proteus mirabilis (145; 5%), Enterobacter spp. (97; 4%), and Citrobacter spp. (78; 3%). The pathogen rank order was similar among regions except for the rarer occurrence of Enterococcus spp. (Rank #6, 4%) in Latin America. E. coli ampicillin resistance was highest in Europe and Latin America (51-55%). Ampicillin (37%), ciprofloxacin or garenoxacin (4%), and trimethoprim/sulfamethoxazole (23%) resistance remained lowest in North America. Nitrofurantoin susceptibility in E. coli was still at acceptable levels and ranged from 91 to 96% across regions. The regional ciprofloxacin-resistant rank order for P. aeruginosa by region was: Latin America (55%) > Europe (41%) > North America (29%). Vancomycin-resistant enterococci (VRE) were only detected in North America (7%). Garenoxacin possessed a 34 to 44% wider spectrum compared to ciprofloxacin against enterococci UTI isolates. Extended spectrum beta-lactamase rates for E. coli and Klebsiella spp. were 4 and 19%, respectively. These results emphasized the need to assess the often striking differences in pathogen occurrence and resistance rates among the commonly encountered UTI pathogens.     

Occurrence and antimicrobial susceptibility patterns of pathogens isolated from skin and soft tissue infections: report from the SENTRY Antimicrobial Surveillance Program (United States and Canada, 2000)

A total of 1,404 bacterial isolates were recovered from skin and soft tissue infections (SSTIs) from hospitalized patients in 24 sites in the United States (US) and 5 Canadian medical centers as part of the SENTRY Antimicrobial Surveillance Program. Isolates were collected between October and December, 2000. The rank order of pathogens was: Staphylococcus aureus (45.9%), Pseudomonas aeruginosa (10.8%), Enterococcus spp. (8.2%), Escherichia coli (7.0%), Enterobacter spp. (5.8%) and Klebsiella spp. (5.1%). The same order was observed in the US and Canada. Of note, almost 30% of S. aureus were oxacillin-resistant. Vancomycin resistance among enterococci was low (7.8%) representing a marked decrease from earlier SENTRY Program reports. Several antimicrobial agents remained very active against P. aeruginosa and Enterobacteriaceae isolates. In particular amikacin, cefepime, and the carbapenems (imipenem and meropenem) showed an excellent spectrum of activity (>95% susceptible). Extended-spectrum beta-lactamase production was observed in both E. coli (7.1%) and Klebsiella spp. (11.3%). Cefepime remained highly active, even against ceftazidime-resistant isolates of Enterobacter spp. The results of this study have identified the most common causes of SSTIs in hospitalized patients in North America, and can be used to make informed decisions concerning standards of empiric treatment for SSTIs in this region.     

Characteristics of pathogens causing urinary tract infections in hospitals in North America: results from the SENTRY Antimicrobial Surveillance Program, 1997.

Urinary tract infection (UTI) is common and involves pathogens with changing susceptibility patterns. The SENTRY Antimicrobial Surveillance Program evaluates international pathogen incidence patterns to detect and manage the emergence of resistant strains. We describe the antimicrobial resistance patterns among 1617 pathogens recovered from UTIs during the third-quarter of 1997 in North America (United States and Canada), as part of this worldwide program. The isolates were tested against more than 50 antimicrobial agents (20 reported) by reference broth microdilution methods, and selected isolates were characterized by pulsed-field gel electrophoresis (PFGE) and automated ribotyping. The five most frequently isolated species were Escherichia coli (48.6%), Enterococcus spp. (13.7%), Klebsiella spp. (12.0%), Pseudomonas aeruginosa (6.2%), and Enterobacter spp. or Proteus mirabilis (3.8% each). For each nation, imipenem and cefepime produced the widest spectrum of coverage among the beta-lactams and amikacin was best among the aminoglycosides. For Gram-negative species, high resistance among beta-lactam antimicrobial agents was noted especially for various penicillins against E. coli (37.9% to 42.8%) and for the cephalosporins tested against enterococci (99.4% and 100%). Approximately 7.0% of enterococci in the USA were vancomycin-resistant (88% with Van A). P. aeruginosa provided the most consistent levels of resistance, but the following agents were most active against these organisms: amikacin (96.6 to 97.4% susceptible), tobramycin (89.5 to 100.0%), piperacillin/tazobactam (89.5 to 100.0%), piperacillin (89.5 to 96.6%), imipenem (89.7 to 92.1%), cefepime (77.6 to 89.7%), and ceftazidime (82.9 to 86.2%). E. coli (2.2 to 2.7%), K. pneumoniae (6.2 to 6.4%), and a single Enterobacter cloacae strain produced extended-spectrum beta-lactamases; and five other Enterobacter spp. were likely to have expressed chromosomally mediated (Amp C) Stably derepressed cephalosporinases with associated resistance to ceftazidime (16.7 to 21.2% resistance). These data demonstrated that several UTI isolates in SENTRY hospitals have high levels of resistance to various classes of antimicrobial agents with little evidence of clonal dissemination.     

Assessment of pathogen frequency and resistance patterns among pediatric patient isolates: report from the 2004 SENTRY Antimicrobial Surveillance Program on 3 continents

Selecting empiric or directed therapy for pathogens isolated from pediatric patients can be problematic. Many antimicrobial agents are not indicated for use in pediatric patients, and regional variations of resistance mechanisms have been reported. The purpose of this study was to analyze antimicrobial resistance patterns and pathogen occurrence rates in pediatric-aged patient infections on 3 continents using data from the SENTRY Antimicrobial Surveillance Program. A total of 3537 clinical isolates were collected from 47 medical centers in 2004. With a protocol that dictated a sampling of 80 consecutive isolates from children (< or =18 years of age), all samples were forwarded to a central laboratory for reference susceptibility testing. Broth microdilution methods and current Clinical and Laboratory Standards Institute breakpoint criteria were used. The 15 most frequently observed pathogens accounted for 93.6% of all isolates. Staphylococcus aureus was the most common pathogen isolated in North America (27.4%) and Europe (19.0%), but Escherichia coli was most common in Latin America (19.3%). All Streptococcus pneumoniae strains from North America and Latin America were susceptible to the newer fluoroquinolones, gatifloxacin and levofloxacin. However, 2 S. pneumoniae strains from Italy were resistant to gatifloxacin, levofloxacin, and ciprofloxacin (> or =4 microg/mL). Ribotype and pulsed-field gel electrophoresis patterns found that these resistant pneumococci were clonal. Numerous strains of Klebsiella spp. (22.5%), E. coli (4.5%), and Proteus mirabilis (4.9%) exhibited phenotypic extended-spectrum beta-lactamase resistance patterns. Four Pseudomonas aeruginosa strains (3 from Latin America and 1 from Europe) were multidrug resistant, 2 P. aeruginosa isolates from Turkey were resistant to polymyxin B (> or =4 microg/mL), and 8.7% of Stenotrophomonas maltophilia isolates from Latin America were resistant to the "drug of choice", trimethoprim/sulfamethoxazole. Physicians should be aware of pathogen occurrences that vary by children's age, geographic location, and prior antimicrobial exposure. Therefore, continued surveillance will be necessary to monitor emerging antimicrobial resistance in the pediatric patient population, especially because new agents such as the fluoroquinolones are used to a greater extent in this age group.     

Skin and soft tissue infections in Latin American medical centers: four-year assessment of the pathogen frequency and antimicrobial susceptibility patterns

We report the results of pathogen frequency and antimicrobial susceptibility of isolates collected from skin and soft tissue infections (SSTIs) in Latin American medical centers during the first 4 years (1997-2000) of the SENTRY Antimicrobial Surveillance Program. Ten laboratories participated each year distributed among nine cities in six countries. A total of 1,789 bacterial isolates were susceptibility tested by reference broth microdilution at the coordinating central laboratory. Results from isolates collected during the year 2000 were compared with those from isolates collected during the prior three years. Selected carbapenem-resistant Pseudomonas aeruginosa were genotyped by automated ribotyping to evaluate the occurrence of clonal, epidemic dissemination. The five most frequently isolated species were (n/%): Staphylococcus aureus (584/32.8%), Escherichia coli (233/13.1%), P. aeruginosa (211/11.9%), Enterococcus spp. (137/7.7%), and Klebsiella spp. (127/5.8%). The most problematic antimicrobial resistances were related to the high prevalence of multi-drug resistant (MDR) Gram-negative bacilli. Carbapenem resistance among non-fermentative Gram-negative bacilli was much higher than that reported in other regions evaluated in the SENTRY Program. Only 74.9% of P. aeruginosa and 84.9% of Acinetobacter spp. were considered susceptible to imipenem. The antimicrobial susceptibility rates of P. aeruginosa decreased during the study period for most antimicrobial agents evaluated. More than 40% of K. pneumoniae and nearly 10% of E. coli showed an extended spectrum beta-lactamase phenotype. Only 73.4% of E. coli and 76.0% of Enterobacter spp. were susceptible to ciprofloxacin. The molecular typing of carbapenem-resistant P. aeruginosa demonstrated clonal dissemination in two institutions. These reported results indicate that rates of resistance among isolates causing SSTI continue to raise in Latin America, with specific concerns for the high prevalence of MDR Gram-negative bacilli. National and international surveillance programs as a guide to focusing intervention strategies should assist in the control of escalating antimicrobial resistance in this geographic area.     

Bacterial pathogens isolated from patients with skin and soft tissue infections: frequency of occurrence and antimicrobial susceptibility patterns from the SENTRY Antimicrobial Surveillance Program (United States and Canada, 1997). SENTRY Study Group (North America).

As part of the SENTRY Antimicrobial Surveillance Program, 1562 bacterial isolates were recovered from hospitalized patients with skin and soft tissue infections (SSTIs) in 30 United States (U.S.) and 8 Canadian medical centers between October and December, 1997. The overall rank order of recovery of the six most common pathogens was Staphylococcus aureus (42.6%) > Pseudomonas aeruginosa (11.3%) > Enterococcus spp. (8.1%) > Escherichia coli (7.2%) > Enterobacter spp. (5.2%) > beta-hemolytic streptocci (5.1%). With one exception, essentially the same order was observed in both the U.S. and Canada. The single exception was the Enterococcus group, which were the third most common isolate in the U.S. (9.6%), but the seventh most common isolate in Canada (3.7). Of note, 24.0% of S. aureus isolates were oxacillin resistant; vancomycin was uniformly active. Vancomycin resistance among Enterococcus spp. (16.5%) was observed only in the U.S. Several antimicrobial agents remained broadly active for SSTI isolates of P. aeruginosa, including meropenem, amikacin, tobramycin, and piperacillin with or without tazobactam. Imipenem resistance (MICs, > or = 8 micrograms/mL) was observed in 11.9% of isolates of P. aeruginosa and ceftazidime, and cefepime had equivalent activity (85.2% and 85.8% susceptible, respectively). Numerous beta-lactams, aminoglycosides and fluoroquinolones were broadly active against E. coli SSTI isolates (i.e. < 5% resistance). Extended-spectrum beta-lactamase production was uncommon both with E. coli and Klebsiella spp. in both nations. Cefepime, imipenem, and meropenem; the aminoglycosides; and fluoroquinolones were conspicuously more active against Enterobacter spp. than other agents tested. High-level, stably derepressed Amp C beta-lactamase production was commonly observed in this group (26.8%), but cefepime generally retained activity against these ceftazidime-resistant organisms. The results of this study serve to define the most common bacterial causes of SSTIs in North America, elucidate patterns of antimicrobial resistance and can be used as a basis for making initial empiric antimicrobial management decisions in hospitalized patients with such infections.     

Antibacterial activity of 41 antimicrobials tested against over 2773 bacterial isolates from hospitalized patients with pneumonia: I--results from the SENTRY Antimicrobial Surveillance Program (North America, 1998)

Pneumonia is the second most frequent cause of nosocomial infection, and hospitalization frequently is needed for community-acquired pneumonia. Knowledge of causative pathogens through periodic surveillance, and their prevailing antimicrobial susceptibility patterns becomes paramount in choosing appropriate empiric therapy. The SENTRY Antimicrobial Surveillance Program, tracks pathogen distribution worldwide since 1997 and documents emerging resistance to a wide range of antimicrobial agents. During the respiratory disease season in 1998, each of 30 medical centers (25 in the United States [US], and five in Canada [CAN]) contributed 100 consecutive isolates obtained from hospitalized patients with suspected pneumonia. The 2773 organisms, processed by the monitor consisted of a total of 35 species, with Staphylococcus aureus comprising 25.6% of all isolates and five other species (Pseudomonas aeruginosa 18.7%, Haemophilus influenzae 9.4%, Streptococcus pneumoniae 7.8%, Klebsiella spp. 7.0%, and Enterobacter spp. 6.7%) making up almost 50% of the total. In the US, pneumococci (8.5%) were more prevalent than in CAN (4.1%; p = 0.001). The US isolates of S. pneumoniae were variably susceptible to penicillin (76.8%), with non-susceptible strains demonstrating greater levels of cross resistance to macrolides (31.8%), cefepime (9.0%) and cefotaxime (6.8%), but remaining susceptible to gatifloxacin and quinupristin/dalfopristin. H. influenzae and Moraxella catarrhalis were generally ampicillin-resistant, 40.4-44.4% and 93.7-95.7%, respectively. P. aeruginosa remained very susceptible to amikacin (91.3-93.8%) > tobramycin > meropenem > piperacillin/tazobactam > gentamicin > piperacillin > cefepime (80.0-81.8%). Extended spectrum beta-lactamase phenotypes among the Klebsiella spp. were isolated from five medical centers in the US and were 4.8-6.0% overall; a rate similar to the previous year. Among the US isolates of Enterobacter spp., only 77.6% and 79.6% were susceptible to ceftazidime and cefotaxime, respectively, but >90% were inhibited by cefepime, imipenem, meropenem, aminoglycosides, and fluoroquinolones. Isolates from CAN were generally more susceptible, except for Pseudomonas isolates, where resistance to aminoglycosides, fluoroquinolones and imipenem was greater. The SENTRY Program results outline important national differences in the frequencies of pathogen occurrence, but more importantly, identify unstable patterns of resistance to available antimicrobial drugs, and serves as a reference for results of other local, national or international investigations.     

Geographic variations in garenoxacin (BMS284756) activity tested against pathogens associated with skin and soft tissue infections: report from the SENTRY Antimicrobial Surveillance Program (2000)

The antimicrobial activity of garenoxacin, a des-(6)F quinolone (formally BMS284756 and T-3811), was evaluated against 2,537 skin and soft tissue infection (SSTI) isolates from the SENTRY Antimicrobial Surveillance Program. Strains isolated in 2000 from Europe, North and Latin America were tested at a central laboratory using reference broth microdilution methods. The rank order of the seven most frequent SSTI pathogens was: Staphylococcus aureus (39.9%), Pseudomonas aeruginosa (12.1%), Escherichia coli (9.7%), Enterococcus spp. (7.7%), Klebsiella spp. (5.8%), Enterobacter spp. (5.6%) and coagulase-negative staphylococci (CoNS; 4.2%). Garenoxacin exhibited a four-fold greater activity (MIC(90), 0.06 microg/ml) compared to levofloxacin (MIC(90), 0.25 microg/ml) against oxacillin-susceptible S. aureus; and oxacillin-resistant staphylococci were more susceptible to garenoxacin (>/=90.5%) at Europe > North America). Continued development of garenoxacin as a treatment of pathogens that commonly cause SSTIs appears to be warranted.     

Contemporary causes of skin and soft tissue infections in North America, Latin America, and Europe: report from the SENTRY Antimicrobial Surveillance Program (1998-2004)

The morbidity and cost for cure associated with skin and soft tissue infections (SSTIs) have recently become more complicated because of the increasing prevalence of multidrug-resistant pathogens associated with this healthcare problem. The SENTRY Antimicrobial Surveillance Program has been monitoring SSTI since 1997, and now presents data from 3 continents over a 7-year period (1998-2004). Isolates were tested by reference broth microdilution methods at a central laboratory using the Clinical and Laboratory Standards Institute (formerly the National Committee for Clinical Laboratory Standards) methods and interpretative criteria. The predominant pathogens included Staphylococcus aureus (ranked 1st in all geographic regions), Pseudomonas aeruginosa, Escherichia coli, and Enterococcus spp. A considerable variation in the methicillin (oxacillin)-resistant S. aureus rate was noted between countries and continents, with the overall rate highest in North America (35.9%) compared with Latin America (29.4%) and Europe (22.8%). Vancomycin-resistant Enterococcus spp. increased in Europe (4.1%) and North America (6.2%) during the period, but remained low and relatively unchanged in Latin America. Among the P. aeruginosa isolates tested, susceptibility to imipenem was much lower in Latin America (65.3%) compared with the other regions (80.7-88.7%), and resistance being associated with an increase in metallo-beta-lactamase-producing strains in Latin America and in some European countries. Multidrug-resistant strains of P. aeruginosa were also more of a concern in Latin America (24.7%) compared with Europe (10.8%) or North America (3.2%). Latin America also had the highest occurrence of extended-spectrum beta-lactamase-producing isolates among E. coli (15.1%) and Klebsiella spp. (48.0%) when compared with other regions. Continued surveillance of pathogen prevalence and antimicrobial resistance patterns should provide information that is important to improve empiric care particularly in the hospital environment.     

In vitro evaluation of cefepime and other broad-spectrum beta-lactams in 22 medical centers in Japan: a phase II trial comparing two annual organism samples. The Japan Antimicrobial Resistance Study Group

An antimicrobial resistance surveillance study in Japan is presented representing the second year (Phase II) results from 22 medical centers. Each participant laboratory tested (Etest, AB BIODISK, Solna, Sweden) 100 organisms, 10 strains each from 10 species groups including Escherichia coli, Klebsiella spp., Enterobacter spp., Citrobacter spp., indole-positive Proteae, Serratia spp., Acinetobacter spp., Pseudomonas aeruginosa, and oxacillin-susceptible Staphylococcus aureus and coagulase-negative staphylococci. Generally only modest variations in the activity of the studied broad-spectrum beta-lactams was observed compared to the study a year before. Specifically, extended spectrum beta-lactamase (ESBL) rates in E. coli increased (2.9 to 8.1%), but the ESBL rate in Klebsiella spp. fell (8.6 to 5.0%). Overall the resistance to the beta-lactams varied from a 4.7% decrease (ceftazidime as a consequence of a modified staphylococcal breakpoint criteria) to a 1.0% increase (cefepime, not significant). The rank order of spectrums in 1998 only changed for cefoperazone-sulbactam (6.1% resistance) that was active against more strains than cefpirome (6.8% resistance). The overall spectrum rank order for the 1998 Japan sample (% resistance) was: cefepime (3.2%) > imipenem (4.1%) > cefoperazone-sulbactam (6.1%) > cefpirome (6.8%) > ceftazidime (8.4%) > piperacillin (19.9%). As with a similar study in 1997, imipenem-resistant isolates of P. aeruginosa and Serratia spp. were discovered with metalloenzymes, usually found in the same medical centers. These results demonstrate the continued in vitro activity and potential sustained clinical efficacy of several broad-spectrum beta-lactams in Japan. Rapid emergence of new or novel resistance were not wide spread using a precise quantitative MIC system. Continued surveillance in this nation would be prudent to document the activity of this clinically valuable class of safe, antimicrobial agents.     

Occurrence and antimicrobial resistance pattern comparisons among bloodstream infection isolates from the SENTRY Antimicrobial Surveillance Program (1997-2002)

The empiric treatment of patients with bloodstream infections (BSI) has become more complicated in an era of increasing antimicrobial resistance. The SENTRY Antimicrobial Surveillance Program has monitored BSI from patients in medical centers worldwide since 1997. During 1997-2002, a total of 81,213 BSI pathogens from North America, Latin America, and Europe were tested for antimicrobial susceptibility. S. aureus, E. coli, and coagulase-negative staphylococci were the three most common BSI pathogens in all three regions each year. Prevalence variability was noted in regions for some species, including higher rates of isolation of E. coli in Europe, Enterococcus spp. in North America, and Gram-negative enteric and nonenteric species in Latin America. Patient age analysis showed the most common BSI pathogen among neonates was coagulase-negative staphylococci and among elderly patients, E. coli. Resistance among BSI pathogens was much more prevalent in nosocomial infections and in patients in intensive care units (ICUs); age differences were also noted. Geographically, oxacillin-resistant S. aureus (39.1%, 2002) and vancomycin-resistant enterococci (17.7%, 2002) were highest in North America, and extended-spectrum beta-lactamase-producing Klebsiella spp. (35.8-46.7%) and multidrug-resistant P. aeruginosa (18.7%, 2002) were highest in Latin America. Activity of commonly used antimicrobial agents remained relatively stable in North America, except in the case of vancomycin-resistant enterococci (20% decline between 1997 and 2002). An epidemiologic investigation of oxacillin-resistant S. aureus in North America identified 10 significant clones (ribotypes) and the common resistance patterns associated with them. Surveillance of BSI pathogens is needed to determine trends of resistance and provide useful information regarding patient risk factors and geographic differences.     

Multicenter evaluation of antimicrobial resistance to six broad-spectrum beta-lactams in Colombia: comparison of data from 1997 and 1998 using the Etest method. The Colombian Antimicrobial Resistance Study Group

The minimum inhibitory concentrations of six broad-spectrum beta-lactam antimicrobial agents were determined in 1998 by use of the Etest versus a total of 823 bacteria in 11 Colombian hospital laboratories. These data were compared with results of a similar study conducted in 1997. The organisms tested included 532 recent clinical isolates of Enterobacteriaceae, 108 Pseudomonas aeruginosa, 94 Acinetobacter species, and 89 oxacillin-susceptible Staphylococcus aureus. Extended-spectrum beta-lactamase production was noted among 27.8 to 33.9% of Escherichia coli isolates and 41.7 to 46.7% of Klebsiella spp. isolates. Hyperproduction of Amp C cephalosporinases was observed with 10.5 to 31.4% of isolates of Enterobacter spp., Serratia spp., and Citrobacter spp. An increase in resistance to all of the beta-lactams was observed among Enterobacteriaceae, Acinetobacter spp. and P. aeruginosa when 1998 results were compared with those obtained in 1997. The overall rank order of activity of the six beta-lactams tested in 1998 versus all clinical isolates was imipenem (93.2% susceptible) > cefoperazone/sulbactam (84.1%) > cefepime (80.9%) > ceftazidime (70.7%) > aztreonam (65.7%) > cefotaxime (65.6%). In contrast, the rank order of these same agents tested against a similar collection of Colombian isolates in 1997 was imipenem (96.6% susceptible) > cefepime (93.6%) > cefoperazone/sulbactam (90.5%) > cefotaxime (74.9%) > aztreonam (74.3%) > ceftazidime (73.2%).     

Frequency of occurrence and antimicrobial susceptibility patterns for pathogens isolated from latin american patients with a diagnosis of pneumonia: results from the SENTRY antimicrobial surveillance program (1998)

The correct empiric choice of antimicrobial therapy in the treatment of pneumonia in hospitalized patients has established itself as a major therapeutic challenge to clinicians. Selection of an inappropriate antimicrobial agent could lead to increased rates of mortality and morbidity. Characteristics of pathogens responsible for this infection such as species prevalence, overall antimicrobial resistance rates, and mechanisms of detected resistance could serve as an invaluable resource to clinicians in making such therapeutic selections. This report addresses the aforementioned problems/needs by analysis of 712 strains isolated from the lower respiratory tract of patients hospitalized with a diagnosis of pneumonia in 10 Latin American medical centers in the SENTRY Antimicrobial Surveillance Program (1998). The four most frequently isolated pathogens (no/% of total) were: Pseudomonas aeruginosa (191/26.8%), Staphylococcus aureus (171/24.0%), Klebsiella spp. (86/12.1%), and Acinetobacter spp. (75/10.5%); representing nearly 75.0% of all isolates. More than 40 antimicrobial agents (23 reported) were tested against these isolates by reference broth microdilution methodology, and susceptibility profiles were established. The nonfermentative Gram-negative bacteria (P. aeruginosa and Acinetobacter spp.) exhibited high levels of resistance to the agents tested. Amikacin (77.5% susceptible) was the most active drug tested against P. aeruginosa 50.0% against the Acinetobacter spp. isolates. Based on published interpretive criteria, over 22.0% of the Klebsiella spp. and 12.5% of the Escherichia coli were classified as extended spectrum beta-lactamase (ESBL) producers. Of the cephalosporin class compounds tested against the Klebsiella spp. and E. coli isolates, cefepime demonstrated the highest rates of susceptibility (84.9% and 91.7%, respectively). This compound also fared well against the Enterobacter spp. isolates, inhibiting 88.2% of the isolates tested, many of which were resistant to ceftazidime and ceftriaxone. Resistance to oxacillin among the S. aureus isolates was nearly 50. 0%, with vancomycin, teicoplanin, and the streptogramin combination quinupristin/dalfopristin inhibiting all isolates. Several clusters of multiply resistant organisms were also observed, and further characterization by ribotyping and pulsed-field gel electrophoresis established possible patient-to-patient spread. The results of this study indicate that rates of resistance among respiratory tract pathogens continue to rise in Latin America, with specific concerns for the high prevalence of nonfermentative Gram-negative bacteria isolated, oxacillin resistance rates in S. aureus, and the epidemic dissemination of multiply-resistant strains in several medical centers. International surveillance programs (SENTRY) should assist in the control of escalating antimicrobial resistance in this geographic area.     

Respiratory tract pathogens isolated from patients hospitalized with suspected pneumonia in Latin America: frequency of occurrence and antimicrobial susceptibility profile: results from the SENTRY Antimicrobial Surveillance Program (1997-2000)

In spite of the recent medical advances, lower respiratory tract infections are still the most frequent infectious causes of mortality worldwide. The objective of this study was to determine the frequency of occurrence and antimicrobial susceptibility of bacterial isolates collected from hospitalized patients with pneumonia in Latin American medical centers during the first four years of the SENTRY Program. The five most frequently isolated species were (n/%): Pseudomonas aeruginosa (659/26.3%), Staphylococcus aureus (582/23.3%), Klebsiella pneumoniae (255/10.2%), Acinetobacter spp. (239/9.6%), and Enterobacter spp. (134/5.4%). P. aeruginosa demonstrated high rates of resistance to most of the antimicrobials tested. Against P. aeruginosa, the most active agents were meropenem (MIC(50), 1 microg/ml; 71.6% susceptible), amikacin (MIC(50), 4 microg/ml; 71.0% susceptible), and piperacillin/tazobactam (MIC(50), 16 microg/ml; 70.4% susceptible). Imipenem (MIC(50), 1 microg/ml; 84.1% susceptible) and meropenem (MIC(50), 2 microg/ml; 84.9% susceptible) were the most active agents against Acinetobacter spp. followed by tetracycline (MIC(50), 相似文献   

Potency and spectrum of tigecycline tested against an international collection of bacterial pathogens associated with skin and soft tissue infections (2000-2004)

The antimicrobial activity of tigecycline, a novel glycylcycline, was evaluated against 5289 bacterial isolates recovered from hospitalized patients with skin and soft tissue infections during 2000-2004. Strains were submitted from >70 medical centers in North America, Latin America, and Europe, and were tested centrally using reference broth microdilution methods. The top 10 ranking pathogens (95% of total) recovered included Staphylococcus aureus (55.2%), Enterococcus spp. (9.6%), Pseudomonas aeruginosa (6.4%), Escherichia coli (5.6%), beta-hemolytic streptococci (5.0%), coagulase-negative staphylococci (4.9%), Enterobacter spp. (2.8%), Klebsiella spp. (2.6%), Proteus mirabilis (1.7%), and indole-positive Proteae (1.2%). All staphylococci (S. aureus and coagulase-negative staphylococci), enterococci, beta-hemolytic streptococci, viridans group streptococci, and E. coli were inhibited by < or =2 microg/mL of tigecycline; in addition, 97% of Klebsiella spp., 95% of Enterobacter spp., and 97% of Acinetobacter spp. were inhibited at this concentration. Only P. aeruginosa and all Proteae (MIC90, 16 microg/mL) displayed elevated MIC values to tigecycline. The broad spectrum of activity exhibited by this glycylcycline included tetracycline-resistant organism subsets, as well as oxacillin-resistant S. aureus, vancomycin-resistant enterococci, and extended-spectrum beta-lactamase-producing enteric bacilli strains. Tigecycline represents a new choice among broad-spectrum parenteral agents for the common Gram-positive and -negative pathogens producing serious infections of skin and soft tissues.     

In vitro evaluation of cefepime and other broad-spectrum beta-lactams against bacteria from Indonesian medical centers. The Indonesia Antimicrobial Resistance Study Group

The in vitro activity of cefepime and six other broad-spectrum beta-lactams (cefpirome, ceftazidime, ceftriaxone, imipenem, piperacillin/tazobactam (4 micrograms/mL fixed concentration), and oxacillin was evaluated against 191 isolates of clinical bacteria from Indonesia. Susceptibility testing was performed using Etest (AB BIODISK, Solna, Sweden) methodology. Isolates from 10 species groups were selected for analysis: Escherichia coli, Klebsiella spp., Enterobacter spp., indole-positive Proteae, Serratia spp., Acinetobacter spp., Pseudomonas aeruginosa, and oxacillin-susceptible staphylococci. The overall rank order of spectrum of activity was (% resistant): imipenem (2.2%) > cefepime (7.3%) > piperacillin/tazobactam > cefpirome > ceftazidime > ceftriaxone (16.2%). The "fourth-generation" cephalosporins, cefepime and cefpirome, displayed greater activity compared with the "third-generation" cephalosporins, ceftazidime, and ceftriaxone, against the 60 E. coli and Klebsiella spp. (30 each) isolates. Phenotypic extended spectrum beta-lactamase occurrence rates among the E. coli and Klebsiella spp. were 23.3 and 33.3%, respectively. Imipenem, cefepime, and cefpirome inhibited 95.7% of the 46 isolates of inducible Amp C cephalosporinase producing Enterobacteriaceae. The majority of the resistance observed to imipenem and cefepime among tested Indoneisian strains was attributable to the nonfermentative Gram-negative bacilli, P. aeruginosa and Acinetobacter spp. These results indicate the presence of beta-lactam resistance in Indonesia and the need for continued antimicrobial surveillance in this nation and region of the world, preferably using accurate quantitative methods.     

Four-year evaluation of frequency of occurrence and antimicrobial susceptibility patterns of bacteria from bloodstream infections in Latin American medical centers

As part of the Latin American arm of the SENTRY Antimicrobial Surveillance Program, 7,207 bacterial isolates collected consecutively from bloodstream infections (BSI) during the period of January 1997 through December 2000 were analyzed. Ten Latin American laboratories located in six countries participated in the study during each year. Antimicrobial susceptibility testing was performed using the reference NCCLS broth microdilution method. The most frequently isolated species were (n/%): Staphylococcus aureus (1,532/21.3%), Escherichia coli (1,239/17.2%), coagulase-negative Staphylococcus (1,002/13.9%), Klebsiella pneumoniae (664/9.2%), and Pseudomonas aeruginosa (470/6.5%). The prevalence of S. aureus as a cause of BSI increased from 20.5% in 1997 to 23.3% in 2000 (p = 0.011), but oxacillin-resistance rates remained relatively stable during this period (around 30%). Enterococci (216 isolates) showed low rates of resistance to both vancomycin (2.4%) and ampicillin (7.9%) and 72.7% of 289 Streptococcus pneumoniae isolates evaluated were susceptible to penicillin (MIC 相似文献   

Pathogen of occurrence and susceptibility patterns associated with pneumonia in hospitalized patients in North America: results of the SENTRY Antimicrobial Surveillance Study (2000)

Antimicrobial selection for patients diagnosed with pneumonia is a major therapeutic challenge and dilemma to the clinical practitioner. In the community setting, patients usually receive empiric oral therapy based upon multiple patient risk factors and locally prevalent pathogen susceptibilities. For patients admitted to the hospital with pneumonia, or who acquire pneumonia while in the hospital, therapy can be initially empiric and then become directed once culture and susceptibility results are known. The SENTRY Antimicrobial Surveillance Program since 1997, has monitored pathogen frequency and antimicrobial susceptibilities in hospitalized patients with pneumonia in North America. In this Study 2,712 pathogens were studied from 30 medical centers (25 in the United States and 5 in Canada). Over 30 species of organisms were recovered with Staphylococcus aureus comprising 28.0% of all isolates and with four other species (Pseudomonas aeruginosa 20.0%, Streptococcus pneumoniae 9.1%, Klebsiella spp. 7.5% and Haemophilus influenzae 7.3%) constituted 71.9% of isolates submitted. Methicillin (oxacillin)-resistant S. aureus accounted for 43.7% of all S. aureus isolates. Antimicrobials demonstrating significant (>80%) activity against S. aureus were: chloramphenicol (81.6%), tetracycline (91.4%), rifampin (96.4%) and quinupristin/dalfopristin (99.7%); and no isolate was resistant to glycopeptides or linezolid. North American isolates of P. aeruginosa were most susceptible to amikacin (93.7%) > tobramycin (90.2%) > meropenem (89.1%) > imipenem = piperacillin/tazobactam (85.6%) > piperacillin (82.1%) > cefepime (80.5%). Overall, 32.1% of S. pneumoniae were penicillin non-susceptible while erythromycin susceptibility was only 74.8%. Fluoroquinolones and recent generation cephalosporins retained excellent activity (gatifloxacin [99.2%] > levofloxacin = cefepime [98.8%] > ceftriaxone [97.2%]) against S. pneumoniae. Klebsiella spp. were 100.0% susceptible to the carbapenems (meropenem and imipenem) but extended spectrum beta-lactamases were detected at a rate of 5.4%. The beta-lactamase-positive rate in H. influenzae was 28.6% in North America (71.4% ampicillin-susceptible). The SENTRY Antimicrobial Surveillance Program continues to identify important North American patterns of pathogen frequency and resistance. Additionally, the provision of multi-year longitudinal data and associated reports allow for comparisons, which function as critical tools for effective patient management and antimicrobial interventions.     

Potency and spectrum of garenoxacin tested against an international collection of skin and soft tissue infection pathogens: report from the SENTRY antimicrobial surveillance program (1999-2004)

The spectrum and potency of garenoxacin, a novel des-F(6)-quinolone, against a large international collection (11723 strains) of Gram-positive and Gram-negative bacterial pathogens that cause skin and soft tissue infections (SSTIs) were evaluated for the years 1999 to 2004. Consecutive nonduplicate bacterial isolates were collected from patients with documented community-acquired or nosocomial SSTI in >70 medical centers participating in the SENTRY Antimicrobial Surveillance Program in North America (37.4%), Europe (26.7%), Latin America (16.7%), and the Asia-Pacific region (19.2%). All isolates were tested using the reference broth microdilution methods against garenoxacin, ciprofloxacin, levofloxacin, gatifloxacin, moxifloxacin, and representative comparator agents used for the empiric or directed therapy for SSTI. Ranking pathogens producing SSTI during these years included Staphylococcus aureus (42.8%), Pseudomonas aeruginosa (11.1%), Escherichia coli (9.0%), Enterococcus spp. (7.3%), Klebsiella spp. (4.8%), Enterobacter spp. (4.7%), beta-hemolytic streptococci (4.3%), coagulase-negative staphylococci (4.0%), Proteus mirabilis (2.5%), and Acinetobacter spp. (2.1%). Garenoxacin was the most potent agent tested against S. aureus and was at least 2-fold more active than gatifloxacin (MIC(50), 0.06 mg/L) and 8-fold more active than levofloxacin (MIC(50), 0.25 mg/L). Furthermore, garenoxacin was 2- to 8-fold more potent than the fluoroquinolones against beta-hemolytic and viridans group streptococci, as well as up to 4-fold more active against enterococci. Garenoxacin was largely comparable with the comparator fluoroquinolones against E. coli, Klebsiella spp., and Acinetobacter spp., but it is less active than these agents against P. aeruginosa. In summary, garenoxacin was documented to be the most potent quinolone when tested against key Gram-positive pathogens (S. aureus, beta-hemolytic streptococci, viridans group streptococci, and enterococci) and was similar in activity to these agents against other species (Enterobacteriaceae and Acinetobacter spp.). These in vitro data suggest that garenoxacin warrants further clinical studies in SSTI, especially against staphylococci and streptococcal pathogens.