Search

Objectives: To investigate the susceptibility of imipenem-non-susceptible Escherichia coli (INS-EC), Klebsiella pneumoniae (INS-KP), Acinetobacter baumannii (INS-AB) and Pseudomonas aeruginosa (INS-PA) to novel antibiotics., Methods: MICs were determined using the broth microdilution method. Carbapenemase and ESBL phenotypic testing and PCR for genes encoding ESBLs, AmpCs and carbapenemases were performed., Results: Zidebactam, avibactam and relebactam increased the respective susceptibility rates to cefepime, ceftazidime and imipenem of 17 INS-EC by 58.8%, 58.8% and 70.6%, of 163 INS-KP by 77.9%, 88.3% and 76.1% and of 81 INS-PA by 45.7%, 38.3% and 85.2%, respectively. Vaborbactam increased the meropenem susceptibility of INS-EC by 41.2% and of INS-KP by 54%. Combinations of β-lactams and novel β-lactamase inhibitors or β-lactam enhancers (BLI-BLE) were inactive against 136 INS-AB. In 58 INS-EC and INS-KP with exclusively blaKPC-like genes, zidebactam, avibactam, relebactam and vaborbactam increased the susceptibility of the partner β-lactams by 100%, 96.6%, 84.5% and 75.9%, respectively. In the presence of avibactam, ceftazidime was active in an additional 85% of 20 INS-EC and INS-KP with exclusively blaOXA-48-like genes while with zidebactam, cefepime was active in an additional 75%. INS-EC and INS-KP with MBL genes were susceptible only to cefepime/zidebactam. The β-lactam/BLI-BLE combinations were active against INS-EC and INS-KP without detectable carbapenemases. For INS-EC, INS-KP and INS-AB, tigecycline was more active than omadacycline and eravacycline but eravacycline had a lower MIC distribution. Lascufloxacin and delafloxacin were active in <35% of these INS isolates., Conclusions: β-Lactam/BLI-BLE combinations were active in a higher proportion of INS-EC, INS-KP and INS-PA. The susceptibility of novel fluoroquinolones and tetracyclines was not superior to that of old ones., (© The Author(s) 2021. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Objectives: We aimed to determine susceptibilities of Elizabethkingia spp. to 25 commonly tested and 8 novel antibiotics, and to compare the performance of different susceptibility testing methods., Methods: Clinical isolates of Elizabethkingia spp., Chryseobacterium spp. and Flavobacterium spp. collected during 2002-18 (n = 210) in a nationwide surveillance programme in Taiwan were speciated by 16S rRNA sequencing. MICs were determined by broth microdilution. The broth microdilution results of 18 common antibiotics were compared with those obtained by the VITEK 2 automated system., Results: Among the Elizabethkingia spp. identified (n = 108), Elizabethkingia anophelis was the most prevalent (n = 90), followed by Elizabethkingia meningoseptica (n = 7) and Elizabethkingia miricola cluster [E. miricola (n = 6), Elizabethkingia bruuniana (n = 3) and Elizabethkingia ursingii (n = 2)]. Most isolates were recovered from respiratory or blood specimens from hospitalized, elderly patients. PFGE showed two major and several minor E. anophelis clones. All isolates were resistant to nearly all the tested β-lactams. Doxycycline, minocycline and trimethoprim/sulfamethoxazole inhibited >90% of Elizabethkingia spp. Rifampin inhibited E. meningoseptica (100%) and E. anophelis (81.1%). Fluoroquinolones and tigecycline were active against E. meningoseptica and E. miricola cluster isolates. Novel antibiotics, including imipenem/relebactam, meropenem/vaborbactam, ceftazidime/avibactam, cefepime/zidebactam, delafloxacin, eravacycline and omadacycline were ineffective but lascufloxacin inhibited half of Elizabethkingia spp. The very major discrepancy rates of VITEK 2 were >1.5% for ciprofloxacin, moxifloxacin and vancomycin. Major discrepancy rates were >3% for amikacin, tigecycline, piperacillin/tazobactam and trimethoprim/sulfamethoxazole., Conclusions: MDR, absence of standard interpretation criteria and poor intermethod concordance necessitate working guidelines to facilitate future research of emerging Elizabethkingia spp., (© The Author(s) 2020. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Objectives: This study investigated the trend in antimicrobial resistance among group B Streptococcus (GBS) from a national surveillance programme in Taiwan and delineated characteristics of and factors associated with levofloxacin-resistant isolates., Methods: Clinical isolates of all sample types and patient groups were collected from multiple hospitals biennially between 2002 and 2012. Susceptibilities to different antibiotics were determined by broth microdilution. Molecular studies of levofloxacin-resistant isolates included serotyping, PFGE, mutations in the QRDRs and MLST., Results: A total of 1559 isolates were tested and all remained susceptible to penicillin, cephalosporins, meropenem and vancomycin. However, levofloxacin resistance increased from 2.2% (range 0%-3.3%) in 2002-06 to 6.2% (5.9%-7.5%) in 2008-12 (P = 0.016). Among the 88 levofloxacin-resistant isolates, the majority (79.5%) had the GyrA(S81L)+ParC(S79F/Y) double mutations and most (54.5%) were also resistant to clindamycin, erythromycin and tetracycline. The predominant genotype of the levofloxacin-resistant isolates was ST19/serotype III (43.2%). Four previously unreported genotypes, ST1 and its single-locus variants (ST920 and ST922)/serotype VI (28.4%) and ST1/serotype II (18.2%), were found to have circulated locally. Serotype III isolates were predominately from urine and female genital tract specimens and <65-year-old adult outpatients, while serotype II and VI isolates were mostly from respiratory and urine samples and >65-year-old inpatients. Multivariate analysis revealed that elderly age and respiratory samples were independent factors associated with levofloxacin resistance., Conclusions: Multiclonal emergence and dissemination of levofloxacin-resistant GBS isolates occurred in healthcare and community settings in Taiwan. Continuous molecular-level surveillance is important to detect new epidemic trends., (© The Author 2017. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Drug-resistant Klebsiella pneumoniae, especially extended-spectrum β-lactamase (ESBL)- and/or AmpC β-lactamase-producing strains, is an emerging problem worldwide. However, few data focusing on drug susceptibility of K. pneumoniae from community is available. In this study, we analyzed 1016 K. pneumoniae isolates from outpatients or those visiting emergency rooms collected during 2002-2012 from Taiwan Surveillance of Antimicrobial Resistance program. Significantly decreased susceptibilities to 3 rd generation cephalosporins and ciprofloxacin were found during the study period. By 2012, susceptibility to cefotaxime and ciprofloxacin was 83.6% and 81.6%, respectively. The prevalence of ESBL-producers increased from 4.8% in 2002 to 11.9% in 2012 (P = 0.012), while that of AmpC β-lactamase-producers increased from 0% to 9.5% in the same period (P < 0.001). Phylogenic analysis of the ESBL and AmpC-β-lactamase-producers by pulsed-field gel electrophoresis and multi-locus sequence typing revealed wide genetic diversity even among the most common sequence type 11 isolates (33.0%). By multivariate analysis, later study year, elderly, and urine isolates were associated with carriage of ESBL genes, while only urine isolates were associated with carriage of AmpC β-lactamase genes. Further studies are needed to determine which antibiotics are reasonable empirical therapy options for patients presenting with severe sepsis that might be caused by K. pneumoniae.

Longitudinal nationwide surveillance data on antimicrobial non-susceptibility and prevalence of extended-spectrum β-lactamases (ESBLs) as well as AmpC β-lactamases producers among Escherichia coli from different sources in the community settings are limited. Such data may impact treatment practice. The present study investigated E. coli from outpatients and patients visiting emergency rooms collected by the Taiwan Surveillance of Antimicrobial Resistance (TSAR) program. A total of 3481 E. coli isolates were studied, including 2153 (61.9%) from urine and 1125 (32.3%) from blood samples. These isolates were collected biennially between 2002 and 2012 from a total of 28 hospitals located in different geographic regions of Taiwan. Minimum inhibitory concentrations (MIC) were determined using methods recommended by the Clinical Laboratory Standards Institute (CLSI). The prevalence and factors associated with the presence of ESBL and AmpC β-lactamase-producers were determined. Significant increases in non-susceptibility to most β-lactams and ciprofloxacin occurred during the study period. By 2012, non-susceptibility to cefotaxime and ciprofloxacin reached 21.1% and 26.9%, respectively. The prevalence of ESBL- and AmpC- producers also increased from 4.0% and 5.3%, respectively, in 2002-2004, to 10.7% for both in 2010-2012 (P < 0.001). The predominant ESBL and AmpC β-lactamase genes were CTX-M and CMY-types, respectively. Non-susceptibility of urine isolates to nitrofurantoin remained at around 8% and to fosfomycin was low (0.7%) but to cefazolin (based on the 2014 CLSI urine criteria) increased from 11.5% in 2002-2004 to 23.9% in 2010-2012 (P <0.001). Non-susceptibility of isolates from different specimen types was generally similar, but isolates from elderly patients were significantly more resistant to most antimicrobial agents and associated with the presence of ESBL- and AmpC- β-lactamases. An additional concern is that decreased ciprofloxacin susceptibility (MIC 0.12-1 mg/L) was as high as 25% in isolates from all age groups, including those from pediatric patients. Our data indicated that there is a need to re-evaluate appropriate treatment selection for community-acquired infections in Taiwan. Identification of community reservoirs of multidrug-resistant E. coli is also warranted.

Background: Longitudinal nationwide data on antimicrobial susceptibility in Proteus mirabilis from different sources are rare. The effects of the revised Clinical and Laboratory Standards Institute (CLSI) β-lactam breakpoints on susceptibility rates and on detecting extended-spectrum β-lactamase (ESBL) and AmpC β-lactamase-producers in this species are also seldom evaluated. The present study analyzed data from the Taiwan Surveillance of Antimicrobial Resistance program to address these issues., Methods: Isolates were collected biennially between 2002 and 2012 from 25 to 28 hospitals in Taiwan. Minimum inhibitory concentrations (MIC) were determined by reference broth microdilution method. All isolates with aztreonam, ceftazidime, or cefotaxime MIC ≥ 2 mg/L were checked for the presence of ESBL by CLSI confirmatory test and subjected to ESBL and AmpC β-lactamases gene detection by PCR. Univariate and multivariate analyses were performed., Results: Between 2002 and 2012, a total of 1157 P. mirabilis were studied. Susceptibility to cefotaxime, ceftazidime, and ciprofloxacin decreased significantly during the past decade, from 92.6% to 81.7%, 100% to 95.2%, and 80.1% to 53.8%, respectively (P < 0.01). The revised CLSI breakpoints had significant impact on susceptibility to cefazolin (2009 vs. current breakpoints, 71.9% vs. 0.9%) and imipenem (99.8% vs. 55.1%) (P < 0.001 for both). However, using the 2014 cefazolin breakpoints for urinary tract infections, 81.2% of the urine isolates were susceptible. Susceptibilities of isolates from different specimen types were mostly similar but outpatient isolates were more susceptible than inpatient isolates. The overall prevalence of ESBL- and AmpC- producers was 8.2% and 4.7%, respectively, but AmpC carriage increased significantly over the years (from 0 to 7.0%, P < 0.001). ESBL and AmpC β-lactamase-producers were more likely to be found in elderly and ICU patients. The predominant ESBL and AmpC β-lactamase genes were CTX-M- and CMY- types, respectively., Conclusions: A significant decrease in susceptibility to 3rd-generation cephalosporins and ciprofloxacin occurred in P. mirabilis from Taiwan in the past decade. The prevalence of ESBL remained stable but AmpC β-lactamase-producing P. mirabilis increased significantly. Cefotaxime was a better surrogate than ceftazidime for predicting the presence of these β-lactamases. Continuous surveillance on antimicrobial resistance and associated resistance mechanisms in P. mirabilis is warranted.

Levofloxacin resistance in Haemophilus influenzae has increased significantly in Taiwan, from 2.0% in 2004 to 24.3% in 2010 (p<0.001). Clinical and molecular investigations of 182 levofloxacin-resistant isolates revealed that the increase was mainly the result of the spread of several clones in the elderly population in different regions.

Our multicenter nationwide surveillance data indicated that erythromycin (ERY) resistance among group A Streptococcus (GAS) isolates in Taiwan declined from 53.1% in 1998 and 2000 to 14.6% in 2002 and 2004 and 10.7% in 2006 to 2010 (P < 0.01). The present study aimed to assess the epidemiology of GAS in Taiwan and identify factors associated with ERY resistance. All 127 ERY-resistant (ERY(r)) isolates and 128 randomly selected ERY-susceptible (ERY(s)) isolates recovered from 1998 to 2010 were emm typed. ERY(r) isolates were also characterized by ERY resistance phenotype and mechanisms and pulsed-field gel electrophoresis (PFGE). Multilocus sequence typing was performed on selected ERY(r) isolates. The predominant emm types in ERY(r) isolates were emm22 (n = 33, 26.0%), emm12 (n = 24, 18.9%), emm4 (n = 21, 16.5%), and emm106 (n = 15, 11.8%). In ERY(s) isolates, emm12 (n = 27, 21.9%), emm1 (n = 18, 14.1%), emm106 (n = 16, 12.5%), and emm11 (n = 9, 7.1%) predominated. The most common ERY resistance phenotype was the M phenotype (resistant to macrolides) (70.9%), with all but one isolate carrying mef(A), followed by the constitutive macrolide-lincosamide-streptogramin B resistance (cMLSB) phenotype (26.8%), with isolates carrying erm(B) or erm(TR). ERY(r) isolates of the emm12-sequence type 36 (ST36) lineage with the cMLSB phenotype were mostly present before 2004, while those of the emm22-ST46 lineage with the M phenotype predominated in later years. Recovery from respiratory (throat swab) specimens was an independent factor associated with ERY resistance. emm1 and emm11 GAS isolates were significantly associated with ERY(s), while emm22 was detected only in ERY(r) GAS. In addition, emm106 isolates were prevalent among the abscess/pus isolates, whereas emm12 isolates were strongly associated with a respiratory (throat) origin. In addition to identifying factors associated with ERY resistance in GAS, our study provides helpful information on the changing GAS epidemiology in Taiwan.

Longitudinal national data on resistance in Enterococcus faecalis and E. faecium from different sources in Taiwan are rare. The present study analyzed data from the Taiwan Surveillance of Antimicrobial Resistance program to address this issue. Between 2002 and 2010, a total of 1696 E. faecalis and 452 E. faecium isolates were studied. Although these 2 species together comprised similar percentages of all enterococci in each study year (94.1-97.2%, P = 0.19), the proportion of E. faecium increased from 12.4% in 2002 to 27.3% in 2010 (P < 0.001). The most noteworthy change in susceptibilities of these 2 species was vancomycin resistance in E. faecium (VREfm), which increased from 0.3% in 2004 to 24.9% in 2010 (P < 0.001). VREfm prevalence differed significantly between geographic regions, patient age groups, and locations. Multidrug resistance was very common in both species even in isolates from outpatients (82.7% for E. faecalis and 98.1% for E. faecium), at rates similar to those from intensive care unit (ICU) and non-ICU patients (80.5-80.9% in E. faecalis and 97.2-98.6% in E. faecium). Nonsusceptibility to linezolid was <0.5% in both species. All tested isolates were susceptible to daptomycin. Continuous surveillance of VRE prevalence and survey of community reservoirs of multidrug-resistant enterococci are warranted., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Background: Acinetobacter baumannii complex (ABC) has emerged as an important pathogen causing a variety of infections. Longitudinal multicenter surveillance data on ABC from different sources in Taiwan have not been published. Using data from the Taiwan Surveillance of Antimicrobial Resistance (TSAR) conducted biennially, we investigated the secular change in resistance of 1640 ABC from 2002 to 2010 (TSAR period III to VII) to different antimicrobial agents and identified factors associated with imipenem-resistant and extensively drug-resistant ABC (IRABC and XDRABC)., Methods: Isolates were collected by TSAR from the same 26 hospitals located in all 4 regions of Taiwan. Minimum inhibitory concentrations (MIC) were determined by reference broth microdilution method. Isolates nonsusceptible to all tested aminoglycosides, fluoroquinolones, β-lactam, β-lactam/β-lactam inhibitors, and carbapenems were defined as extensively drug-resistant (XDR). Multivariate logistic regression analysis was performed to assess the relationship between predictor variables among patients with resistant ABC and patients with non-resistant ABC., Results: The prevalence of IRABC increased from 3.4% in 2002 to 58.7% in 2010 (P < 0.001; odds ratio [OR], 2.138; 95% confidence interval [CI], 1.947 to 2.347) and that of XDRABC increased from 1.3% in 2002 to 41.0% in 2010 (P < 0.001; OR, 1.970; 95% CI, 1.773-2.189). The rates of non-susceptibility to other antimicrobial agents remained high (>55%) over the years with some fluctuations before and after TSAR V (2006) on some agents. Multivariate analysis revealed that recovery from elderly patients, origins other than blood, from ICU settings, or geographic regions are independent factors associated with IRABC and XDRABC. Although the prevalence of XDRABC increased in all four regions of Taiwan over the years, central Taiwan had higher prevalence of XDRABC starting in 2008. Susceptibility to polymyxin remained high (99.8%)., Conclusions: This longitudinal multicenter surveillance program revealed significant increase and nationwide emergence of IRABC and XDRABC in Taiwan over the years. This study also identified factors associated with IRABC and XDRABC to help guide empirical therapy and at-risk groups requiring more intense interventional infection control measures with focused surveillance efforts.

Although the presence of mecA is the genotypic determinant of methicillin-resistant Staphylococcus aureus (MRSA), certain MRSA strains, especially community-associated MRSA (C-MRSA), can display an oxacillin MIC in the Clinical and Laboratory Standards Institute susceptible breakpoint range (≤ 2 μg/ml). Among 91 and 180 isolates thought to be methicillin-susceptible S. aureus (MSSA) with oxacillin MICs of 2 and 1 μg/ml as determined by the Sensititre broth microdilution test initially, 52 (57.1%) and 6 (3.3%), respectively, were mecA positive. These mecA-positive low-oxacillin-MIC isolates belong to the dominant Taiwan C-MRSA clone (clonal complex [CC] 59), 56 of which carried SCCmec type V and were pvl positive, and 43 of which belonged to spa CC t437. All 271 isolates were retested by Sensititre, as well as by Vitek II and disk diffusion (DD). Based on the oxacillin results, the sensitivities of the Sensititre, Vitek II, and DD methods were 48.3% (28/58), 46.6% (27/58), and 89.6% (52/58), respectively. Although cefoxitin was better at detecting these isolates, 12.1, 10.4, and 5.2% of these isolates were still misidentified as MSSA by Sensititre, Vitek II, and DD, respectively. These results highlight the difficulty in the accurate identification of MRSA with borderline oxacillin MICs in the CC59:SCCmec V clone, which likely has contributed to its spread in the health care and community settings. Since this clone has now been detected in other countries, and since other C-MRSA lineages have also been found to have low-level β-lactam resistance, the findings of the present study may be relevant to other regions. Further studies are warranted to determine the extent and clinical impact of such misidentification.

Background: Stenotrophomonas maltophilia has emerged as an important opportunistic pathogen in debilitated hosts. Clinical management of S. maltophilia is challenging due to its intrinsic resistance to a variety of antibiotics. This study investigated the trend and prevalence of antimicrobial resistance in S. maltophilia from a nationwide surveillance study in Taiwan., Methods: S. maltophilia isolates were collected biennially between 1998 and 2008 as part of the Taiwan Surveillance of Antimicrobial Resistance (TSAR) program from medical centers and regional hospitals throughout Taiwan. Minimal inhibitory concentrations (MIC) were determined using the Clinical and Laboratory Standards Institute reference broth microdilution method., Results: A total of 377 non-duplicate S. maltophilia isolates were collected from 38 hospitals. The majority of the isolates were from the respiratory tract (256, 67.9%), followed by blood (48, 12.7%). Overall, 376 (99.7%) isolates were susceptible to minocycline, 362 (96%) to tigecycline, 311 (82.5%) to trimethoprim/sulfamethoxazole (TMP-SMX), 300 (79.6%) to levofloxacin, 92 (24.4%) to ceftazidime, and 70 (18.6%) to ticarcillin-clavulanic acid. The MIC(50)/MIC(90) of minocycline, tigecycline, TMP-SMX, levofloxacin, ceftazidime, and ticarcillin-clavulanic acid, were ≤0.5/1 μg/mL, 0.25/1 μg/mL, ≤0.25/8 μg/mL, 1/4 μg/mL, 32/128 μg/mL, and 64/128 μg/mL, respectively. A trend of increased non-susceptibility to levofloxacin (p=0.014) was observed over the 10-year study period. Compared to TMP-SMX-susceptible isolates, TMP-SMX-resistant isolates were less susceptible to levofloxacin (54.5% vs. 84.9%, p<0.001)., Conclusion: In this 10-year study, minocycline and TMP-SMX remained the two antimicrobials with better in vitro activities against S. maltophilia than ceftazidime, levofloxacin, and ticarcillin-clavulanic acid. The activity of levofloxacin against S. maltophilia in Taiwan declined during the past 10 years., (Copyright © 2011. Published by Elsevier B.V.)

The in vitro antibacterial activities of nemonoxacin (TG-873870), a novel nonfluorinated quinolone, against 770 clinical isolates were investigated. Nemonoxacin (tested as its malate salt, TG-875649) showed better in vitro activity than ciprofloxacin and levofloxacin against different species of staphylococci, streptococci, and enterococci, Neisseria gonorrhoeae, and Haemophilus influenzae. The in vitro activity of TG-875649 was also comparable to or better than that of moxifloxacin against these pathogens, which included ciprofloxacin-resistant, methicillin-resistant Staphylococcus aureus and levofloxacin-resistant Streptococcus pneumoniae.

A plasmid containing the qnrS quinolone resistance determinant and the gene encoding the SHV-2 beta-lactamase has been discovered from a clinical Klebsiella pneumoniae strain isolated in Taiwan. The complete 98-kb sequence of this plasmid, designated pK245, was determined by using a whole-genome shotgun approach. Transfer of pK245 conferred low-level resistance to fluoroquinolones in electroporant Escherichia coli epi300. The sequence of the immediate region surrounding qnrS in pK245 is nearly identical (>99% identity) to those of pAH0376 from Shigella flexneri and pINF5 from Salmonella enterica serovar Infantis, the two other qnrS-carrying plasmids reported to date, indicating a potential common origin. Other genes conferring resistance to aminoglycosides (aacC2, strA, and strB), chloramphenicol (catA2), sulfonamides (sul2), tetracycline (tetD), and trimethoprim (dfrA14) were also detected in pK245. The dfrA14 gene is carried on a class I integron. Several features of this plasmid, including three separate regions containing putative replicons, a partitioning-control system, and a type II restriction modification system, suggest that it may be able to replicate and adapt in a variety of hosts. Although no critical conjugative genes were detected, multiple insertion sequence elements were found scattered throughout pK245, and these may facilitate the dissemination of the antimicrobial resistance determinants. We conclude that pK245 is a chimera which acquired its multiple antimicrobial resistance determinants horizontally from different sources. The identification of pK245 plasmid expands the repertoire of the coexistence of quinolone and extended-spectrum-beta-lactam resistance determinants in plasmids carried by various species of the family Enterobacteriaceae in different countries.

Of the 798 clinical Salmonella isolates collected from multiple hospitals in Taiwan, resistance to ampicillin (48.5%), chloramphenicol (55.3%), streptomycin (59.0%), sulfamethoxazole (68.0%), and tetracycline (67.8%) was high, whereas resistance to all 5 antimicrobials (ACSSuT R-type) comprised 327 (41%) and was highly prevalent in Salmonella enterica serotype Typhimurium (72.7%, 176/242), the most common serotype. Additional resistance to trimethoprim was present in 155 (19.4% overall) of the ACSSuT R-type isolates from several serotypes. Reduced susceptibility to fluoroquinolone (FQ) (ciprofloxacin MIC >0.125-1 microg/mL and nalidixic acid-resistant) was detected in 223 (27.9%) isolates including 117 (14.7% overall) that were also ACSSuT-resistant. Full resistance to FQ was detected in Salmonella Choleraesuis (35.5%, 6/17) and Salmonella Schwarzengrund (16.7%, 10/60); both serotypes were also multiresistant to other antimicrobials. Studies are needed to determine the sources of different multidrug-resistant serotypes. Continued national surveillance is underway to monitor changes in resistance trends and to detect further emergence of resistant Salmonella serotypes in Taiwan.

In the Taiwan Surveillance of Antimicrobial Resistance programme, isolates were collected from 21 hospitals over a 3-month period in 2000 (TSAR II) and rates of resistance in Gram-positive pathogens were determined. Resistance rates were high including oxacillin resistance in Staphylococcus aureus (60%) and coagulase-negative staphylococci (80%), high-level gentamicin resistance (HLGR) in Enterococcus faecalis (60%) and penicillin non-susceptibility in Streptococcus pneumoniae (69%). Oxacillin resistance had increased from 1998 (TSAR I) and may be spreading into outpatient settings. In contrast, less than 2% enterococci were vancomycin-resistant. No linezolid resistance was found in either staphylococci or enterococci.

In a nationwide surveillance of antimicrobial resistance (Taiwan Surveillance of Antimicrobial Resistance, TSAR), isolates were collected from 21 medical centers and regional hospitals throughout Taiwan over a three-month period in 2000 (TSAR II). This report summarizes susceptibility data of 7 common Gram-negative bacilli (Escherichia coli, Klebsiella pneumoniae, Serratia marcescens, Proteus mirabilis, Enterobacter cloacae, Pseudomonas aeruginosa, and Acinetobacter baumannii) in the TSAR II collection and compared selected key forms of resistance by epidemiologic factors and with isolates collected in 1998 (TSAR I) as well as with data from international surveillance studies. Resistance of the 5 Enterobacteriaceae species to most of the commonly prescribed "first-line" antimicrobials in Taiwan, such as ampicillin (78% in E. coli, 68% in P. mirabilis), gentamicin (19% in K. pneumonia to 66% in S. marcescens), and trimethoprim/sulfamethoxazole (29% in K. pneumoniae to 70% in P. mirabilis), was high, several of which are higher than other countries. Resistance to certain broad-spectrum antimicrobials is also more acute in Taiwan than most Western countries, such as ceftazidime resistant A. baumannii (73%) and ciprofloxacin resistant E. coli (12%). Differences in geographic regions and specimen types were associated with certain forms of resistance in TSAR II; however, the resistance problem is prevalent among both inpatients and outpatients of not only medical centers but also regional hospitals throughout Taiwan.