title: Influence of patient age on the frequency of occurrence and antimicrobial resistance patterns of isolates from hematology/oncology patients: report from the Chemotherapy Alliance for Neutropenics and the Control of Emerging Resistance Program (North America).
abstract: The Chemotherapy Alliance for Neutropenics and the Control of Emerging Resistance Program (CANCER) monitored the susceptibility of pathogens recovered in hematology/oncology centers from 2000 to 2002. A total of 3970 isolates from 32 hospitals (26 United States, 6 Canada) were analyzed at a central location (JMI Laboratories, North Liberty, IA) for trends in pathogen occurrence and reference antimicrobial susceptibility profiles. The top 5 ranking pathogens were Staphylococcus aureus (19.3%), coagulase-negative staphylococci (CoNS) (14.1%), Escherichia coli (13.4%), Enterococcus spp. (10.2%), and Klebsiella spp. (9.5%). A total of 35.5% of S. aureus and 78.8% of CoNS were resistant to oxacillin, whereas 22.0% of Enterococcus spp. were resistant to vancomycin. E. coli and Klebsiella spp. were highly susceptible (>90%) to piperacillin/tazobactam, 3rd-generation cephalosporins, and ciprofloxacin, but 3.9% and 2.4% of these species, respectively, met screening criteria for extended spectrum beta-lactamase production. Enterobacter spp. were less susceptible to piperacillin/tazobactam, ceftazidime, and ceftriaxone (83.7-88.2%) because of Amp C production and were most inhibited by cefepime and imipenem. Amikacin and polymyxin B were very active against Pseudomonas aeruginosa (97.4-97.7% susceptible). Prevalence of S. aureus, E. coli, Enterobacter spp., and Klebsiella spp. increased significantly (+48% to 98%) with age, whereas CoNS and viridans group streptococci decreased markedly (-62% to 69%) with advancing age. The isolation of Gram-positive pathogens declined (55% to 47%) with age (< or =14 to > or =65 years). Fluoroquinolones generally exhibited decreased susceptibility with increased age against nearly all listed pathogens. Oxacillin resistance rates for S. aureus increased with age (6-46%) as did vancomycin resistance rates for enterococci (nil in < or =14 years group to 18-24% in adults). Pathogens infecting neutropenic patients did not reflect greater resistance than those found in the general hospitalized patients. Gram-positive organisms were only slightly more predominant (53.4%), and cited age-related variations in pathogen occurrence and/or susceptibility patterns by species must be considered for empiric regimes for hematology and oncology patients.
authors.affiliation: JMI Laboratories, Inc., North Liberty, IA 52317, USA. jeff-kirby@jmilabs.com
authors.forename: Jeffrey T
authors.initials: JT
authors.lastname: Kirby
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Fritsche
authors.forename: Ronald N
authors.initials: RN
authors.lastname: Jones
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D000970:Antineoplastic Agents; D002170:Canada / Q000453:epidemiology; D002648:Child; D021821:Communicable Diseases, Emerging / Q000188:drug therapy / Q000453:epidemiology*; D024881:Drug Resistance, Bacterial / Q000187:drug effects*; D006801:Humans; D008137:Longitudinal Studies; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D009369:Neoplasms / Q000188:drug therapy / Q000382:microbiology*; D009503:Neutropenia / Q000382:microbiology*; D018571:Sentinel Surveillance; D014481:United States / Q000453:epidemiology
chemical_list: D000900:Anti-Bacterial Agents; D000970:Antineoplastic Agents