Trends in the Susceptibility of Clinically Important Resistant Bacteria to Tigecycline: Results from the Tigecycline In Vitro Surveillance in Taiwan Study, 2006 to 2010

Abstract

The TigecyclineIn VitroSurveillance in Taiwan (TIST) study, a nationwide, prospective surveillance during 2006 to 2010, collected a total of 7,793 clinical isolates, including methicillin-resistantStaphylococcus aureus(MRSA) (n= 1,834), penicillin-resistantStreptococcus pneumoniae(PRSP) (n= 423), vancomycin-resistant enterococci (VRE) (n= 219), extended-spectrum β-lactamase (ESBL)-producingEscherichia coli(n= 1,141), ESBL-producingKlebsiella pneumoniae(n= 1,330),Acinetobacter baumannii(n= 1,645), andStenotrophomonas maltophilia(n= 903), from different specimens from 20 different hospitals in Taiwan. MICs of tigecycline were determined following the criteria of the U.S. Food and Drug Administration (FDA) and the European Committee on Antimicrobial Susceptibility Testing (EUCAST-2011). Among drug-resistant Gram-positive pathogens, all of the PRSP isolates were susceptible to tigecycline (MIC90, 0.03 μg/ml), and only one MRSA isolate (MIC90, 0.5 μg/ml) and three VRE isolates (MIC90, 0.125 μg/ml) were nonsusceptible to tigecycline. Among the Gram-negative bacteria, the tigecycline susceptibility rates were 99.65% for ESBL-producingE. coli(MIC90, 0.5 μg/ml) and 96.32% for ESBL-producingK. pneumoniae(MIC90, 2 μg/ml) when interpreted by FDA criteria but were 98.7% and 85.8%, respectively, when interpreted by EUCAST-2011 criteria. The susceptibility rate forA. baumannii(MIC90, 4 μg/ml) decreased from 80.9% in 2006 to 55.3% in 2009 but increased to 73.4% in 2010. A bimodal MIC distribution was found among carbapenem-susceptibleA. baumanniiisolates, and a unimodal MIC distribution was found among carbapenem-nonsusceptibleA. baumanniiisolates. In Taiwan, tigecycline continues to have excellentin vitroactivity against several major clinically important drug-resistant bacteria, with the exception ofA. baumannii.

Outbreak of Klebsiella pneumoniae Carbapenemase-2-Producing K. pneumoniae Sequence Type 11 in Taiwan in 2011

“…Isolates with the same PST and sequence type (ST) were considered to belong to the same clone. NTUH-9047, the first isolate of KPC-2-producing K. pneumoniae (KPC-2-KP) recovered in Taiwan, was also included in this study (9).…”

Trends in Susceptibility of Vancomycin-Resistant Enterococcus faecium to Tigecycline, Daptomycin, and Linezolid and Molecular Epidemiology of the Isolates: Results from the Tigecycline In Vitro Surveillance in Taiwan (TIST) Study, 2006 to 2010

“…However, the rate of isolation of vancomycin-resistant enterococcus (VRE) strains is on the rise in North America (17), Europe (2), and Asia (4). In Taiwan, a nationwide surveillance study of antimicrobial resistance in patients admitted to intensive care units clearly demonstrated a significant rise in VRE among regional hospitals and medical centers during the period 2003 to 2009 (5). Specifically, at the National Taiwan University Hospital, rates of VRE among all enterococcus species causing health care-associated infection significantly increased, from 1.7% (0.007 per 100 inpatient-days) in 2000 to 25.1% (0.188 per 100 inpatient-days) in 2009 (14).…”

A Snapshot of Co-Resistance to Carbapenems and Tigecycline in Clinical Isolates ofEnterobacter cloacae

“…19,26,27,32 The identification of E. cloacae with simultaneous resistance to both carbapenems and tigecycline, like the isolates studied herein, is therefore of high clinical significance. Tigecycline resistance is known to be associated with the increased expression of efflux systems.…”