The frequency of prescribing antibacterial drugs among the adult population of the United States is constantly increasing. However, the choice of antibiotic regimen in different age groups depends on the diagnosis and the classes of antibacterial drugs used. These data were presented at the 51st Interscience Conference on Antimicrobial Agents and Chemotherapy, held in Chicago in September 2011.

In previous studies, patients in the older age group have been shown to be significantly more likely to receive antimicrobials with a broader spectrum of activity due to age-related characteristics of immune status and multiple concomitant pathologies.

In order to obtain reliable information on this problem, a group of researchers from Oregon State University carried out an analysis of the antibiotic treatment regimens prescribed in adult patients of the oldest age group (65 years and over) compared to younger patients (18-64 years old).

Data were collected using national registries of external medical assistance and for hospitalized patients for the period from 2002 to 2008, which contain information on visits to outpatient facilities and emergency medical calls. The 9th revision of the International Classification of Diseases has been used to identify an infectious disease, including infections of the skin and soft tissues, infections of the genitourinary system and acute respiratory infections.

Out of 798408046 visits, made on average annually, in 17% of "young" patients and in 10% of patients in the most advanced age group, an infectious disease was detected (p less than 0.01). During the study, the percentage of visits during which the doctor prescribed an antibacterial drug increased in “young” patients from 12% to 18% (p less than 0.01) and in patients in group d most advanced age from 8% to 16% (p less than 0.01).

In particular, the prescription of antibiotics for skin and soft tissue infections increased from 65% to 79% in “young” patients (p less than 0.01) and from 59% to 73% in patients of the older age group (p = 0.2). The percentage of antibacterial drugs for urinary tract infections increased from 76% to 83% in "young" patients (p = 0.05) and from 46% to 71% in patients in the older age group ( p = 0.13). The proportion of patients receiving antibacterial drugs for acute respiratory infections increased from 47% to 58% in the older age group (p = 0.59), although this did not change among the "young" patients (64%; p = 0.59).

Patients in the older group were most often treated with drugs from the fluoroquinolone group (p less than 0.01); "young" patients - macrolides (p less than 0.01).