title: Contemporary activity of meropenem and comparator broad-spectrum agents: MYSTIC program report from the United States component (2005).
abstract: The Meropenem Yearly Susceptibility Test Information Collection Program is a 9-year-old antimicrobial resistance surveillance network of more than 100 medical centers worldwide, including 15 sites in the United States (US) that monitors the susceptibility of Gram-negative and Gram-positive bacterial pathogens especially to carbapenems. In 2005, the antimicrobial activity of 11 broad-spectrum agents was assessed against 2910 bacterial isolates (2493 Gram-negative and 417 staphylococci) submitted from the US medical centers to a reference laboratory using Clinical and Laboratory Standards Institute susceptibility testing methods and interpretative criteria. Meropenem continued to demonstrate 1) high potency with MIC(90) values 4- to 16-fold lower than imipenem against the Enterobacteriaceae, 2) equal activity against Pseudomonas aeruginosa, 3) 2-fold less activity compared with imipenem against Acinetobacter spp., and 4) 4- to 8-fold less activity compared with imipenem against the oxacillin-susceptible staphylococci. The wide spectrum of activity for carbapenems against Enterobacteriaceae (1657 strains) was confirmed by the overall rank order by percentage susceptibility at breakpoint criteria: imipenem (98.9%) > meropenem (98.7%) > cefepime (97.6%) > piperacillin/tazobactam (92.0%) > ceftriaxone (91.2%) > aztreonam (90.6%) > gentamicin = tobramycin (90.5%) > ceftazidime (90.4%) > levofloxacin (84.9%) > ciprofloxacin (83.9%). Against Acinetobacter spp. isolates, only tobramycin (92.0% susceptible) and carbapenems (92.0-85.6%) exhibited acceptable levels of activity. A continued increase in the resistance rate for both ciprofloxacin and levofloxacin was observed with highest rates found among indole-positive Proteae species (36.5-33.3%) and Escherichia coli (21.6-20.4%) isolates, some documented by molecular typing methods as clonally related. Ongoing surveillance of meropenem and other broad-spectrum antimicrobial agents appears warranted to monitor the potency and spectrum of activity against indicated Gram-negative and-positive pathogens causing serious infections in the hospital setting, and to detect the emergence of new or novel resistance mechanisms that could compromise clinical utility (serine and metallo-carbapenemases).
authors.affiliation: JMI Laboratories, North Liberty, IA 52317, USA. paul-rhomberg@jmilabs.com
authors.forename: Paul R
authors.initials: PR
authors.lastname: Rhomberg
authors.forename: Ronald N
authors.initials: RN
authors.lastname: Jones
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial; D006090:Gram-Negative Bacteria / Q000187:drug effects*; D016905:Gram-Negative Bacterial Infections / Q000453:epidemiology / Q000382:microbiology; D006801:Humans; D008137:Longitudinal Studies; D000077731:Meropenem; D008826:Microbial Sensitivity Tests; D011159:Population Surveillance; D013203:Staphylococcal Infections / Q000453:epidemiology / Q000382:microbiology; D013210:Staphylococcus / Q000145:classification / Q000187:drug effects*; D013845:Thienamycins / Q000494:pharmacology*; D014481:United States / Q000453:epidemiology
chemical_list: D000900:Anti-Bacterial Agents; D013845:Thienamycins; D000077731:Meropenem