Antibiotic resistance spectrum of E. coli strains from different samples and age-grouped patients: a 10-year retrospective study

OBJECTIVE: Escherichia coli (E. coli) is the most common opportunistic clinical micro-organism with high drug resistance. This study aimed to analyse the resistance pattern of E. coli according to patient age and clinical sample type. DESIGN AND SETTING: This retrospective observational study was conducted in a tertiary hospital in southeastern China. PARTICIPANTS: E. coli strains were isolated from blood, urine and sputum of infected inpatients. The patients were divided into four age groups: children (0–14 years old, including neonatal and non-neonatal groups), youths (15–40 years old), middle-aged (41–60 years old) and old (>60 years old). RESULTS: A total of 7165 E. coli strains were collected from all samples. Compared with urine and blood isolates, more sputum isolates were resistant against 12 tested antibiotics. Furthermore, urine isolates were more resistant to levofloxacin than sputum and blood isolates. Although the patients’ age was not associated with resistance rates of E. coli strains isolated from blood, a larger proportion of urine-derived strains from youths were resistant to sulfamethoxazole-trimethoprim and piperacillin-tazobactam than those from old people. The sputum strains from the elderly were more resistant to most of the tested antibiotics compared with sputum strains isolated from children. CONCLUSIONS: The resistance profile of E. coli is different among age groups and specimen sources and should be considered during E. coli infection treatment.