Antibiotic resistance among clinical isolates of Acinetobacter in the UK, and in vitro evaluation of tigecycline (GAR-936)

Abstract

A survey was conducted of the antimicrobial susceptibilities of 595 Acinetobacter spp. isolated from routine clinical specimens in 54 sentinel laboratories throughout the UK during 2000. Isolates of the Acinetobacter baumannii complex (genomic groups 2, 3 and 13TU; n = 443) were distinguished from other genomic groups (n = 152) by PCR fingerprinting of tDNA spacer regions. MICs of amikacin, cefotaxime, ceftazidime, ciprofloxacin, colistin, gentamicin, imipenem, meropenem, minocycline, piperacillin, piperacillin/tazobactam, rifampicin, sulbactam and tetracycline were determined on IsoSensitest agar and interpreted, wherever possible, using BSAC breakpoints. Tigecycline (GAR-936), a new glycylcycline, was also tested. Resistance to cephalosporins, aminoglycosides and ciprofloxacin was widespread, but carbapenems, colistin, sulbactam, minocycline and tigecycline were each active against >80% of the isolates. Isolates of A. baumannii were more often resistant to cefotaxime, ceftazidime, piperacillin, piperacillin/tazobactam, ciprofloxacin, gentamicin and tetracyclines than those belonging to other genomic groups, but were less often resistant to colistin; no significant differences between genomic groups were noted in the susceptibilities to amikacin, carbapenems, rifampicin or sulbactam. The relative activities of the tetracyclines were minocycline > tigecycline > tetracycline. Thirteen carbapenem-resistant isolates (MICs > or =8 mg/L; 2.2%) were received from six centres; four centres sent single isolates; one sent three and one sent six. An allele of bla(IMP) was detected in one of these isolates, but the other 12 isolates either had carbapenemase-independent resistance, or undetectable carbapenemase activity combined with other resistance mechanisms. In conclusion, carbapenems, colistin and minocycline retained greatest activity against the Acinetobacter isolates collected. Tigecycline was less active than minocycline, but both agents overcame most tetracycline resistance.

Phenotypic and Molecular Characterization ofAcinetobacter baumanniiClinical Isolates from Nosocomial Outbreaks in Los Angeles County, California

“…These results are similar to published reports for clinical isolates from other geographic regions (5,13,28,37,39,51). However, although tigecycline is active in vitro, recent reports indicate that it is far less effective in vivo, with cases of resistance increasingly being reported for A. baumannii (26,31,33).…”

Evaluation of Antimicrobial Susceptibility Among Acintobacter baumannii by E-Test Method at Khatam-Al-Anbia Hospital During 2013 - 2015

“…Today we are facing with the problem of dominance of Acinetobacter baumannii [16] which our study also reached to the same result. Same as other studies our research showed that Acinetobacter has the most relation with respiratory system and most of the positive samples for Acinetobacters were obtained from respiratory secretions and the respiratory tract is the main source of Acinetobacter infection [17,18].…”

Prevalence and diversity of carbapenemases among imipenem-nonsusceptible Acinetobacter isolates in Korea: emergence of a novel OXA-182

“…Carbapenems, colistin, and tigecycline were active against over 80% of A. baumannii complex isolated in 2000 (Henwood et al, 2002). A high colistin resistance rate of 30.6% among A. baumannii isolates from 2 Korean hospitals (Ko et al, 2007) indicated necessity of colistin susceptibility testing in other settings.…”