Multicenter Antimicrobial Research Articles

National surveillance of antimicrobial susceptibilities to ceftaroline, dalbavancin, telavancin, tedizolid, eravacycline, omadacycline, and other comparator antibiotics, and genetic characteristics of bacteremic Staphylococcus aureus isolates in adults: Results from the Surveillance of Multicenter Antimicrobial Resistance in Taiwan (SMART) program in 2020.

Methicillin-resistant Staphylococcus aureus (MRSA) causes invasive infections and is associated with community-acquired infections (CAIs) and hospital-associated infections (HAIs). In 2020, 315 S. aureus isolates, including 145 methicillin-susceptible S. aureus (MSSA) and 170 MRSA, mainly associated with bacteremia and mostly CAIs, were collected from 16 hospitals in different regions of Taiwan. Minimum inhibitory concentrations (MICs) were determined using the Sensititre™ complete automated AST system. Staphylococcal cassette chromosome mec (SCCmec) types were analysed using multiplex polymerase chain reaction. The median age of patients infected with MRSA was significantly higher than that of patients infected with MSSA (72.5 years vs. 67.0 years, P=0.027). MIC50/MIC90 values of eravacycline and omadacycline were 0.06/0.12, and 0.25/0.5, respectively. Of the MRSA isolates, 4.1% presented susceptible dose-dependence to ceftaroline, most of which (85.7%) were HAI- and Panton-Valentine leukocidin (PVL)-negative. Among the MRSA isolates, 7.1% were not susceptible to telavancin and tedizolid (mainly type IV, PVL-negative, and CAI), 0.6% were not susceptible to daptomycin (type III, PVL-negative, and HAI), and 1.8% were not susceptible to quinupristin/dalfopristin (three isolates were type III, IV, and VT, respectively, and all were PVL-negative), but all were susceptible to dalbavancin. In conclusion, patients with bacteremia caused by MRSA were older than those with bacteremia caused by MSSA, SCCmec type IV was more predominant in CAI than in HAI, and MRSA isolates not susceptible to novel anti-MRSA antimicrobials belonged to types II, III, or IV. Further studies that include comprehensive demographics and more detailed descriptions of other antimicrobial-resistant genes are urgently needed.

Multicenter Antimicrobial Resistance Surveillance of Clinical Isolates from Major Hospitals - China, 2022.

Bacterial resistance surveillance is crucial for monitoring and understanding the trends and spread of drug-resistant bacteria. The number of strains collected in 2022 increased compared to 2021. The top five bacteria, including Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, Pseudomonas aeruginosa, and Acinetobacter baumannii, remained largely unchanged. The detection rate of methicillin-resistant strains continued to decrease. Among clinical Enterobacterales isolates, the resistance rate to carbapenems was generally below 13%, except for Klebsiellaspp., which had a resistance range of 20.4% to 21.9%. Most clinical Enterobacterales isolates were highly susceptible to tigecycline, colistin, and polymyxin B, with resistance rates ranging from 0.1% to 12.6%. The detection rate of meropenem-resistant P. aeruginosa and meropenem-resistant Acinetobacter baumannii showed a decreasing trend for the fourth consecutive year. Multidrug-resistant bacteria remain a significant public health challenge in clinical antimicrobial treatment. To effectively address bacterial resistance, it is essential to enhance both bacterial resistance surveillance and the prudent use of antimicrobial agents.

National surveillance of antimicrobial susceptibilities to dalbavancin, telavancin, tedizolid, eravacycline, omadacycline and other comparator antibiotics and serotype distribution of invasive Streptococcus pneumoniae isolates in adults: results from the Surveillance of Multicenter Antimicrobial Resistance in Taiwan (SMART) programme in 2017–2020

ObjectivesThe aim of this study was to investigate the trends in serotypes and in vitro antimicrobial susceptibility of Streptococcus pneumoniae causing adult invasive pneumococcal disease (IPD) to dalbavancin, telavancin, tedizolid, eravacycline, omadacycline and other comparator antibiotics from 2017–2020 following implementation of the 13-valent pneumococcal conjugate vaccine (PCV-13) and during the COVID-19 (coronavirus disease 2019) pandemic.MethodsDuring the study period, 237 S. pneumoniae isolates were collected from non-duplicate patients, covering 15.0% of IPD cases in Taiwan. Antimicrobial susceptibility testing was performed using a Sensititre® system. A latex agglutination method (ImmuLex™ Pneumotest Kit) was used to determine serotypes.ResultsSusceptibility rates were high for vancomycin (100%), teicoplanin (100%) and linezolid (100%), followed by ceftaroline (non-meningitis) (98.3%), moxifloxacin (94.9%) and quinupristin/dalfopristin (89.9%). MIC50 and MIC90 values of dalbavancin, telavancin, tedizolid, eravacycline and omadacycline were generally low. Non-vaccine serotype 23A was the leading cause of IPD across the adult age range. Isolates of serotype 15B were slightly fewer than those of PCV-13 serotypes in patients aged ≥65 years. The overall case fatality rate was 15.2% (36/237) but was especially high for non-PCV-13 serotype 15B (21.4%; 3/14). Vaccine coverage was 44.7% for PCV-13 and 49.4% for the 23-valent pneumococcal polysaccharide vaccine (PPSV-23), but was 57% for both PCV-13 and PPSV-23.ConclusionThe incidence of IPD was stationary after PCV-13 introduction and only dramatically decreased in the COVID-19 pandemic in 2020. The MIC50 and MIC90 values of dalbavancin, telavancin, tedizolid, eravacycline, omadacycline were generally low for S. pneumoniae causing adult IPD.

In-vitro activity of cefiderocol, cefepime/zidebactam, cefepime/enmetazobactam, omadacycline, eravacycline and other comparative agents against carbapenem-nonsusceptible Enterobacterales: results from the Surveillance of Multicenter Antimicrobial Resistance in Taiwan (SMART) in 2017–2020

This study examined the susceptibility of carbapenem-nonsusceptible Enterobacterales (CNSE) to cefiderocol, cefepime/zidebactam, cefepime/enmetazobactam, omadacycline, eravacycline and other comparative agents. Non-duplicate Enterobacterales isolates from 16 Taiwanese hospitals were evaluated. Minimum inhibitory concentrations (MICs) were determined using the broth microdilution method, and susceptibility results were interpreted based on relevant guidelines. In total, 201 CNSE isolates were investigated, including 26 Escherichia coli isolates and 175 Klebsiella pneumoniae isolates. Carbapenemase genes were detected in 15.4% (n=4) of E. coli isolates and 47.4% (n=83) of K. pneumoniae isolates, with the most common being blaKPC (79.3%, 69/87), followed by blaOXA-48-like (13.8%, 12/87). Cefiderocol was the most active agent against CNSE; only 3.8% (n=1) of E. coli isolates and 4.6% (n=8) of K. pneumoniae isolates were not susceptible to cefiderocol. Among the carbapenem-resistant E. coli and K. pneumoniae isolates, 88.5% (n=23) and 93.7% (n=164), respectively, were susceptible to ceftazidime/avibactam. For cefepime/zidebactam, 23 (88.5%) E. coli isolates and 155 (88.6%) K. pneumoniae isolates had MICs ≤2/2 mg/L. For cefepime/enmetazobactam, 22 (84.6%) E. coli isolates and 85 (48.6%) K. pneumoniae isolates had MICs ≤2/8 mg/L. The higher MICs of K. pneumoniae against cefepime/enmetazobactam were due to only one (1.5%) of the 67 blaKPC-carrying isolates being susceptible. MICs of omadacycline were significantly higher than those of eravacycline and tigecycline. In summary, cefiderocol, ceftazidime/avibactam and cefepime/zidebactam were more effective against carbapenem-nonsusceptible E. coli and K. pneumoniae than other drugs, highlighting their potential as valuable therapeutics.

Antimicrobial susceptibility of bacteremic vancomycin-resistant Enterococcus faecium to eravacycline, omadacycline, lipoglycopeptides, and other comparator antibiotics: Results from the 2019–2020 Nationwide Surveillance of Multicenter Antimicrobial Resistance in Taiwan (SMART)

Multicenter surveillance of antimicrobial susceptibility was performed for 235 vancomycin-resistant Enterococcus faecium (VREfm) isolates from 18 Taiwanese hospitals. The minimum inhibitory concentrations (MICs) of eravacycline, omadacycline, lipoglycopeptides, and other comparator antibiotics were determined using the broth microdilution method. Nearly all isolates of VREfm were not susceptible to teicoplanin, dalbavancin, and telavancin, with susceptibility rates of 0.5%, 1.7% and 0.5%, respectively. Tigecycline and eravacycline were active against 93.2% and 89.7% of the VREfm isolates, respectively. Moreover, the susceptibility rates of quinupristin/dalfopristin, tedizolid, and linezolid were 59.1%, 84.2%, and 77.4%, respectively. Additionally, 94% of the VREfm isolates were classified as susceptible to daptomycin, and the MICs of omadacycline required to inhibit VREfm growth by 50% and 90% were 0.12 and 0.5 mg/L, respectively. Susceptibility rates of VREfm isolates to synthetic tetracyclines and daptomycin were slightly lower and to oxazolidinone-class antibiotics were much lower in Taiwan than those in other parts of the world. Continuous monitoring of VREfm resistance to novel antibiotics, including synthetic tetracyclines, oxazolidinone-class antibiotics, and daptomycin, is needed in Taiwan.

National Surveillance of Antimicrobial Susceptibility of Bacteremic Gram-Negative Bacteria with Emphasis on Community-Acquired Resistant Isolates: Report from the 2019 Surveillance of Multicenter Antimicrobial Resistance in Taiwan (SMART).

A multicenter collection of bacteremic isolates of Escherichia coli (n = 423), Klebsiella pneumoniae (n = 372), Pseudomonas aeruginosa (n = 300), and Acinetobacter baumannii complex (n = 199) was analyzed for susceptibility. Xpert Carba-R assay and sequencing for mcr genes were performed for carbapenem- or colistin-resistant isolates. Nineteen (67.8%) carbapenem-resistant K. pneumoniae (n = 28) and one (20%) carbapenem-resistant E. coli (n = 5) isolate harbored blaKPC (n = 17), blaOXA-48 (n = 2), and blaVIM (n = 1) genes.

Nationwide surveillance of antimicrobial resistance among clinically important Gram-negative bacteria, with an emphasis on carbapenems and colistin: Results from the Surveillance of Multicenter Antimicrobial Resistance in Taiwan (SMART) in 2018

Multicentre surveillance of antimicrobial susceptibility of clinically important Gram-negative bacteria (GNB) from 16 Taiwanese hospitals was performed. Escherichia coli (n = 398), Klebsiella pneumoniae (n = 346), Pseudomonas aeruginosa (n = 252) and Acinetobacter baumannii complex (ABC) (n = 188) bloodstream isolates, non-typhoidal Salmonella (n = 230) and Shigella flexneri (n = 18) from various sources were collected. Antimicrobial MICs were determined using broth microdilution. Genes encoding K. pneumoniae carbapenemases (KPCs), New Delhi metallo-β-lactamases (NDMs), Verona integron-encoded metallo-β-lactamase (VIM), OXA-48-like carbapenemase (OXA-48) as well as mcr-1-5 genes were detected by molecular methods. Rates of carbapenem non-susceptibility were 2.8%, 9.0%, 0.4%, 0%, 10.3% and 48.8% for E. coli, K. pneumoniae, Salmonella, Shigella, P. aeruginosa and ABC, respectively. For carbapenemases, one (0.3%) E. coli harboured blaNDM-1. Fifteen (4.3%), two (0.6%) and two (0.6%) K. pneumoniae contained blaKPC, blaOXA-48 and blaVIM, respectively. Two (0.5%) E. coli and fourteen (4.0%) K. pneumoniae were non-wild-type according to the colistin MIC. Among Enterobacteriaceae with a colistin MIC ≥ 2 mg/L, mcr-1 was detected in one E. coli, two K. pneumoniae and three Salmonella spp. All three mcr-1-positive Salmonella isolates were collected from community-acquired infections; none of the six mcr-1-positive Enterobacteriaceae were carbapenem-resistant. Carbapenem resistance has increased among clinically important GNB, especially among hospital-acquired infections. blaKPC, especially the blaKPC-2 variant, was detected in approximately one-half of the carbapenem-resistant K. pneumoniae isolates in this study. Although resistance rates to colistin remained low among Enterobacteriaceae, the finding of mcr-1 from different species raises concern of potential dissemination.

Susceptibility rates of clinically important bacteria collected from intensive care units against colistin, carbapenems, and other comparative agents: results from Surveillance of Multicenter Antimicrobial Resistance in Taiwan (SMART).

ObjectivesThis study aimed to determine the in vitro susceptibility of commonly encountered Gram-negative bacilli (GNB) recovered from patients admitted to intensive care units (ICUs) in Taiwan against colistin, carbapenems, and other comparative agents.MethodsIn total, 758 nonduplicate GNB isolates were obtained from clinical specimens of ICU patients at seven medical centers in 2016. Minimum inhibitory concentrations (MICs) were determined using the Vitek 2 susceptibility system. The reference broth-microdilution method was performed to determine MICs of colistin. Five main carbapenemase genes among carbapenem-non-susceptible GNB and mcr-1–mcr5 genes among colistin non-wild-type or -resistant isolates were determined.ResultsAfter exclusion 38 Proteus mirabilis and 13 Morganella morganii spp. among 361 Enterobacteriaceae isolates, 34 (9.4%) isolates were carbapenem-insusceptible, 91.1% (n=31) were colistin wild type, and three and one Klebsiella pneumoniae isolates carried blaKPC and blaOXA48-like, respectively. Carbapenem-insusceptible isolates were found in 23.4% (30 of 128) and 63.0% (87 of 138) of isolates of the Pseudomonas aeruginosa and Acinetobacter baumannii complex, respectively. mcr-1 was detected in two (1.8%) Enterobacter cloacae isolates. Very major errors between two methods of susceptibility to colistin were found in 1.5% of K. pneumoniae, 27.5% of E. cloacae, 4.7% of P. aeruginosa, and 10.1% of A. baumannii complex isolates.ConclusionIn this study, 8.7% of Enterobacteriaceae isolates from ICUs were not susceptible to carbapenem, and blaKPC and blaOXA48-like were found among three and one carbapenem-insusceptible K. pneumoniae isolates, respectively. Colistin MICs determined by Vitek 2 were not reliable, especially for E. cloacae and A. baumannii complex isolates.

Antimicrobial activities of ceftazidime-avibactam, ceftolozane-tazobactam, and other agents against Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa isolated from intensive care units in Taiwan: results from the Surveillance of Multicenter Antimicrobial Resistance in Taiwan in 2016.

ObjectiveThe aim of this study was to investigate the in vitro antimicrobial susceptibilities of clinically important Gram-negative bacteria from seven intensive care units in Taiwan in 2016.Materials and methodsIn total, 300 non-duplicate isolates of Escherichia coli (n=100), Klebsiella pneumoniae (n=100), and Pseudomonas aeruginosa (n=100) collected from 300 patients were studied. The minimum inhibitory concentrations (MICs) of these isolates to antimicrobial agents were determined using the broth microdilution method. Carbapenemase-encoding genes (blaKPC, blaNDM, blaIMP, blaVIM, and blaOXA-48-like) were studied for the isolates that were not susceptible to any carbapenems. Sequencing analysis of the mcr genes (mcr-1–5) was conducted for all isolates with colistin MICs ≥4 mg/L.ResultsErtapenem non-susceptibility was detected in 3% (n=3) E. coli and 12% (n=12) K. pneumoniae isolates. The susceptibility rates of imipenem, ceftazidime–avibactam (CAZ–AVB), and ceftolozane–tazobactam (CLZ–TAZ) were 99%, 99%, and 88%, respectively, for E. coli, 91%, 100%, and 80%, respectively, for K. pneumoniae, and 66%, 91%, and 93%, respectively, for P. aeruginosa. Carbapenemase-encoding genes were not detected in E. coli, were detected in four (33.3%) K. pneumoniae isolates that were not susceptible to ertapenem (three harboring blaKPC and one harboring blaOXA-48-like), and were not detected in P. aeruginosa isolates that were not susceptible to imipenem. One K. pneumoniae isolate was resistant to colistin (MIC 4 mg/L) and negative for mcr genes.ConclusionCAZ–AVB exhibited excellent activity against carbapenem-resistant Enterobacteriaceae, and CLZ–TAZ exhibited good activity against imipenem-resistant P. aeruginosa.

In vitro activity of ceftazidime–avibactam, ceftolozane–tazobactam, and other comparable agents against clinically important Gram-negative bacilli: results from the 2017 Surveillance of Multicenter Antimicrobial Resistance in Taiwan (SMART)

ObjectivesWe investigated the in vitro antimicrobial susceptibilities of clinically important Gram-negative bacteria (GNB) from 16 major teaching hospitals in Taiwan in 2017.Materials and methodsEscherichia coli (n=686) and Klebsiella pneumoniae bloodstream isolates (n=673), non-typhoid Salmonella (NTS; n=221) from various sources, Shigella species (n=21) from fecal samples, and Neisseria gonorrhoeae (n=129) from the genitourinary tract were collected. Antibiotic minimum inhibitory concentrations (MICs) were determined using the broth microdilution method. Alleles encoding K. pneumoniae carbapenemases (KPCs), New Delhi metallo-β-lactamases (NDMs), Verona integron-encoded metallo-β-lactamase, imipenemase, OXA-48-like, and mcr-1-5 genes were detected by molecular methods in Enterobacteriaceae isolates.ResultsFive (0.7%) E. coli isolates harbored mcr-1 alleles. Twenty-four (3.6%), seven (1.0%), four (0.6%), and one (0.15%) K. pneumoniae isolates contained bla KPC, bla OXA-48-like, mcr-1, and bla NDM, respectively. Three (1.4%) NTS and no Shigella isolates harbored mcr-1 genes. Seventy-one (10.5%) K. pneumoniae isolates displayed non-susceptibility (NS) to carbapenem agent(s). Phenotypically extended-spectrum β-lactamase (ESBL)-producing K. pneumoniae isolates showed significantly higher rates of ertapenem, tigecycline, and ceftolozane–tazobactam (CLZ– TAZ) NS (40.2%, 16.3%, and 71%–80%, respectively) than E. coli isolates exhibiting ESBL phenotypes (5.4%, 0.7%, and 18%–28%, respectively). All phenotypically ESBL-producing E. coli isolates were ceftazidime–avibactam (CAZ–AVB) susceptible. Two (8.3%) KPC-producing K. pneumoniae isolates showed CAZ–AVB NS. Hospital-acquired K. pneumoniae isolates were significantly less susceptible to ertapenem and CLZ–TAZ than hospital-acquired E. coli isolates.ConclusionThird-generation cephalosporins remain the optimal choice for treating NTS, Shigella, and gonococcal infections in Taiwan. Hospital-acquired and phenotypically ESBL-producing K. pneumoniae are a heavy resistance burden in Taiwan.

Corrigendum to “Rates of susceptibility of carbapenems, ceftobiprole, and colistin against clinically important bacteria collected from intensive care units in 2007: Results from the Surveillance of Multicenter Antimicrobial Resistance in Taiwan (SMART)” [J Microbiol Immunol Infect 49 (2016) 969–976

Corrigendum to “Rates of susceptibility of carbapenems, ceftobiprole, and colistin against clinically important bacteria collected from intensive care units in 2007: Results from the Surveillance of Multicenter Antimicrobial Resistance in Taiwan (SMART)” [J Microbiol Immunol Infect 49 (2016) 969–976

Implementation and Success of a Multicenter Antimicrobial Stewardship Network

Implementation and Success of a Multicenter Antimicrobial Stewardship Network

Rates of susceptibility of carbapenems, ceftobiprole, and colistin against clinically important bacteria collected from intensive care units in 2007: Results from the Surveillance of Multicenter Antimicrobial Resistance in Taiwan (SMART).

Data on susceptibility to ceftobiprole and colistin, and the complete evolutionary trends of minimum inhibitory concentrations (MICs) of important carbapenem agents among important pathogens collected in intensive care units (ICUs) in Taiwan are lacking. We surveyed the MIC distribution patterns of ceftobiprole and colistin and susceptibility profiles of some important pathogens collected from patients hospitalized in intensive care units (ICUs) of major teaching hospitals throughout Taiwan in 2007. We also investigated the rates of nonsusceptibility to powerful carbapenems (imipenem, meropenem) among four important species of Enterobacteriaceae (Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae, and Proteus mirabilis) collected during the same period. MIC breakpoints recommended by the Clinical and Laboratory Standards Institute in 2014 were applied. Colistin showed excellent invitro activity (susceptibility rate, 96%) against Acinetobacter baumannii isolates but moderate (73-77% susceptibility rate) activity against isolates of Pseudomonas aeruginosa and E. cloacae. The ceftobiprole MIC90 value was 4μg/mL for methicillin-resistant Staphylococcus aureus and 16μg/mL for P. aeruginosa. The phenotype of methicillin resistance did not markedly increase the MIC value of ceftobiprole among S. aureus isolates. Interestingly, the proportion of isolates that displayed nonsusceptibility to imipenem was significantly higher among P. mirabilis isolates than among isolates of the other three Enterobacteriaceae species, regardless of the production of extended-spectrum β-lactamase. Continuous monitoring of susceptibility profiles of ICU pathogens to important antibiotics is warranted to provide appropriate antimicrobial regimens against infections in the ICU.

Relationship between the distribution of cefepime minimum inhibitory concentrations and detection of extended-spectrum β-lactamase production among clinically important Enterobacteriaceae isolates obtained from patients in intensive care units in Taiwan: Results from the Surveillance of Multicenter Antimicrobial Resistance in Taiwan (SMART) in 2007

The data on susceptibility of important cephalosporins against four Enterobacteriaceae members producing potential extended-spectrum β-lactamase (ESBL) collected from Taiwanese intensive care units are lacking. Minimum inhibitory concentrations (MICs) of cefotaxime, ceftazidime, and cefepime were determined using agar dilution method, against Escherichia coli (n = 344), Klebsiella pneumoniae (n = 359), Enterobacter cloacae (n = 103), and Proteus mirabilis (n = 78). Susceptibilities of these isolates to three cephalosporins were assessed according to MIC breakpoints recommended by the Clinical and Laboratory Standards Institute (CLSI) and the European Committee on Antimicrobial Susceptibility Testing (EUCAST) in 2013. The double-disk synergy test using disks containing cefepime (30 μg) with or without clavulanate (10 μg) was applied to confirm production of ESBL for isolates with cephalosporin MIC ≥ 2 μg/mL. A total of 175 isolates were verified as ESBL producers. The rates of cefepime susceptibility among the ESBL-producing isolates, according to CLSI (EUCAST) criteria, were 56.7% (22.4%) for E. coli, 61.3% (12.0%) for K. pneumoniae, 57.9% (31.6%) for E. cloacae, and 71.4% (7.1%) for P. mirabilis. Using different cefepime MIC breakpoints (MICs ≥ 16 μg/mL recommended by CLSI criteria and ≥ 2 μg/mL by EUCAST criteria) to define nonsusceptibility, we found that both criteria were poorer at predicting ESBL producers among K. pneumoniae and E. cloacae than among the other two species. In addition, we also found that the cefepime MIC level of 1.0 μg/mL best distinguished non-ESBL- from ESBL-producing K. pneumoniae and E. cloacae. To detect ESBLs, CLSI should revise the cefepime MIC breakpoint against Enterobacteriaceae.

Antimicrobial Resistance of Rapidly Growing Mycobacteria in Western Taiwan: SMART Program 2002

To understand the resistance patterns of rapidly growing mycobacteria (RGM) in Taiwan, antimicrobial resistance of clinical isolates was determined as part of the SMART (Surveillance from Multicenter Antimicrobial Resistance in Taiwan) program. During the period from January 2002 to December 2003, clinical isolates were collected from eight hospitals located on the west side of Taiwan and one reference laboratory. Broth microdilution minimum inhibitory concentrations of 11 antimicrobial agents were determined for 312 clinical isolates of RGM, including the Mycobacterium fortuitum group (110 isolates), Mycobacterium abscessus group (168 isolates), and Mycobacterium chelonae group (34 isolates). Nearly all of the RGM were susceptible to amikacin and ofloxacin (= 90%) and resistant to doxycycline (less than 3% susceptible). Tobramycin showed similar in vitro activity against the M. fortuitum and M. chelonae (77%) groups, but was less active against the M. abscessus group (58%). Ciprofloxacin was active mainly against M. fortuitum (95%). Nearly all RGM were resistant to erythromycin and doxycycline. However, around half of the RGM isolates remained susceptible to minocycline (50-54%). Clarithromycin was active against the M. abscessus group (53% susceptible), with a high rate of resistance in the M. chelonae (38% susceptible) and M. fortuitum (15% susceptible) group. Cefoxitin was more active against the M. fortuitum group (65%) than the other two RGM (40-44%), and les than 40% of the RGM isolates remained susceptible to imipenem (21-38%). The resistance of RGM in Taiwan is not as high as previously reported (notably for tobramycin, ciprofloxacin and cefoxitin), but reduction in the susceptibility rates of clarithromycin and imipenem for the M. fortuitum and M. abscessus groups demonstrates the importance of in vitro susceptibility testing of clinically important isolates, as susceptibility may differ in different geographical areas, even regionally, and over time.

Multicenter Antimicrobial Susceptibility Survey of Gram-Negative Bacteria Isolated from Patients with Community-Acquired Infections in the People's Republic of China

A survey of 2,099 gram-negative bacilli from community infections at seven centers in the People's Republic of China is reported. The rates of resistance of 1,615 isolates of the family Enterobacteriaceae were as follows: 40.8% for ciprofloxacin, 32.2% for gentamicin, 0% for imipenem or ertapenem, and 14.7% for cefotaxime. The rates of extended-spectrum beta-lactamase production were 16% for Escherichia coli and 17% for Klebsiella.

Antifungal Susceptibilities of Clinical Isolates of Candida Species, Cryptococcus neoformans , and Aspergillus Species from Taiwan: Surveillance of Multicenter Antimicrobial Resistance in Taiwan Program Data from 2003

The susceptibilities of nonduplicate isolates to six antifungal agents were determined for 391 blood isolates of seven Candida species, 70 clinical isolates (from blood or cerebrospinal fluid) of Cryptococcus neoformans, and 96 clinical isolates of four Aspergillus species, which were collected in seven different hospitals in Taiwan (as part of the 2003 program of the study group Surveillance of Multicenter Antimicrobial Resistance in Taiwan). All isolates of Candida species other than C. glabrata and C. krusei were susceptible to fluconazole. Among the 59 C. glabrata isolates, 16 (27%) were not susceptible to fluconazole, and all were dose-dependently susceptible or resistant to itraconazole. For three (5.1%) C. glabrata isolates, voriconazole MICs were 2 to 4 microg/ml, and for all other Candida species isolates, voriconazole MICs were </=0.5 microg/ml. The proportions of isolates for which amphotericin B MICs were >/=2 microg/ml were 100% (3 isolates) for C. krusei, 11% (23 of 207 isolates) for Candida albicans, 3.0% (2 of 67 isolates) for Candida tropicalis, 20% (12 of 59 isolates) for C. glabrata, and 0% for both Candida parapsilosis and Candida lusitaniae. For three (4%) Cryptococcus neoformans isolates, fluconazole MICs were >/=16 microg/ml, and two (3%) isolates were not inhibited by 1 mug of amphotericin B/ml. For four (4.2%) of the Aspergillus isolates, itraconazole MICs were 8 microg/ml. Aspergillus flavus was less susceptible to amphotericin B, with the MICs at which 50% (1 microg/ml) and 90% (2 microg/ml) nsrsid417869\delrsid7301351 of isolates were inhibited being twofold greater than those for Aspergillus fumigatus and Aspergillus niger. All Aspergillus isolates were inhibited by </=1 microg of voriconazole/ml, including isolates with increased resistance to amphotericin B and itraconazole. This study revealed the emergence in Taiwan of decreased susceptibilities of Candida species to amphotericin B and of C. neoformans to fluconazole and amphotericin B. Voriconazole was the most potent agent against the fungal isolates tested, including fluconazole- and amphotericin B-nonsusceptible strains.

Telithromycin and quinupristin-dalfopristin resistance in clinical isolates of Streptococcus pyogenes: SMART Program 2001 Data.

This study evaluated the current status of antimicrobial resistance in clinical isolates of Streptococcus pyogenes in Taiwan as part of the SMART (Surveillance from Multicenter Antimicrobial Resistance in Taiwan) program. In 2001, 419 different isolates of S. pyogenes, including 275 from respiratory secretions, 87 from wound pus, and 31 from blood, were collected from nine hospitals in different parts of Taiwan. MICs of 23 antimicrobial agents were determined at a central location by the agar dilution method. All of the isolates were susceptible to penicillin (MIC at which 90% of the isolates were inhibited [MIC(90)], <or=0.03 microg/ml), cefotaxime (MIC(90), <or=0.03 microg/ml), cefepime (MIC(90), 0.06 microg/ml), meropenem (MIC(90), <or=0.03 microg/ml), moxifloxacin (MIC(90), 0.25 microg/ml), vancomycin (MIC(90), 0.5 microg/ml), and linezolid (MIC(90), 1 micro g/ml). Overall, 78% of isolates were not susceptible to erythromycin (54% were intermediate, and 24% were resistant), and 5% were not susceptible to clindamycin. Of the 101 erythromycin-resistant isolates, 80.2% exhibited the M phenotype (mefA gene positive), 18.9% exhibited the cMLS (constitutive resistance to macrolides-lincosamides-streptogramin B [MLS]) phenotype (ermB gene positive), and 1% exhibited the iMLS (inducible resistance to MLS) phenotype (ermB gene positive). Fluoroquinolones (sitafloxacin > moxifloxacin > ciprofloxacin = levofloxacin = gatifloxacin > gemifloxacin) demonstrated potent activity against nearly all of the isolates of S. pyogenes tested. Thirty-two isolates (8%) were not susceptible to quinupristin-dalfopristin. Seventeen percent of isolates had telithromycin MICs of >or=1 microg/ml, and all of these isolates exhibited erythromycin MICs of >or=32 microg/ml. The high prevalence of resistance to telithromycin (which is not available in Taiwan) limits its potential use in the treatment of S. pyogenes infections, particularly in areas with high rates of macrolide resistance.