title: Aetiology and antibiotic resistance patterns of urinary tract infections in the elderly: a 6-month study.
abstract: Urinary tract infections (UTIs) are a common cause of bacteraemia in the elderly and are associated with a high probability of hospitalization. Despite the impact of UTIs on health status and quality of life, a limited number of studies have evaluated their aetiology in this population. This study aimed to evaluate the microbial aetiology and pattern of susceptibility of bacteria causing UTIs in the elderly. For this purpose, a retrospective cohort study of elderly residents (n = 472, aged >65 years) in 14 nursing homes in Milan (Italy) and its province was performed. Globally, 393 micro-organisms from 328 samples were isolated: Escherichia coli was the most prevalent (44.8 %), followed by Proteus mirabilis (20.4 %), Providencia spp. (8.9 %), Klebsiella spp. (6.4 %) and Pseudomonas aeruginosa (4.6 %). Enterococci were the most frequently isolated Gram-positive organisms (7.4 %). Almost all Enterobacteriaceae were susceptible to nitrofurantoin, carbapenems and amikacin. Extended-spectrum β-lactamases were detected in 42.1 % of isolates. The most active antibiotics against P. aeruginosa were colistin, amikacin and piperacillin/tazobactam. All Gram-positive organisms were susceptible to glycopeptides and linezolid, and 90 % were susceptible to nitrofurantoin. Fluoroquinolones showed a limited activity against all the tested micro-organisms. Escherichia coli remains the major micro-organism responsible for UTIs in older people, although to a lesser extent than in a younger population. The high rates of resistance observed in this study make careful use of antibiotics advisable to limit further development of resistance.
authors.affiliation: Laboratory of Clinical Chemistry and Microbiology, IRCCS Galeazzi Orthopaedic Institute, Milan, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: De Vecchi
authors.affiliation: Department of Internal Medicine, Sant'Anna Clinic, Merano, Italy.
authors.forename: Simona
authors.initials: S
authors.lastname: Sitia
authors.affiliation: CRIO Unit, IRCCS Galeazzi Orthopaedic Institute, Milan, Italy.
authors.forename: Carlo Luca
authors.initials: CL
authors.lastname: Romanò
authors.affiliation: Clinical Epidemiology and Biometry Unit, IRCCS Policlinico San Donato, Milan, Italy.
authors.forename: Cristian
authors.initials: C
authors.lastname: Ricci
authors.affiliation: Department of Public Health, Microbiology and Virology, University of Milan, Milan, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Mattina
authors.affiliation: Laboratory of Technical Science for Laboratory Medicine, Department of Biomedical Sciences for Health, University of Milan, Milan, Italy.|Laboratory of Clinical Chemistry and Microbiology, IRCCS Galeazzi Orthopaedic Institute, Milan, Italy.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Drago
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D015331:Cohort Studies; D024881:Drug Resistance, Bacterial; D004755:Enterobacteriaceae / Q000145:classification / Q000187:drug effects* / Q000201:enzymology / Q000302:isolation & purification*; D004756:Enterobacteriaceae Infections / Q000453:epidemiology / Q000382:microbiology; D005260:Female; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008297:Male; D008826:Microbial Sensitivity Tests; D009735:Nursing Homes / Q000706:statistics & numerical data; D012189:Retrospective Studies; D014552:Urinary Tract Infections / Q000453:epidemiology / Q000382:microbiology; D001618:beta-Lactamases / Q000096:biosynthesis
chemical_list: D000900:Anti-Bacterial Agents; D001618:beta-Lactamases