Duration of colonization with extended-spectrum β-lactamase-producing Enterobacteriaceae

Abstract

Extended Spectrum Beta-Lactamase-producing Enterobacteriaceae (ESBL-PE) are an emerging concern in public health. Antimicrobial use, hospitalization and foreign travel are associated with human carriage of ESBL-PE. Duration of carriage with ESBL-PE can vary. The main objective of this thesis is to provide an overview of the current scientific knowledge on persistence of ESBL carriage in humans. In addition, risk factors for duration of ESBL carriage will be described. After a literature search, 14 studies met the criterion that duration of ESBL-PE was assessed. Eight studies were conducted in patients, two in NICU patients, and four in non-patients (travelers, adopted children, medical students). Approximately half of adult (hospitalized) patients carried ESBL-PE after 6 months (range 33-53%). After 12 months, this percentage was around 25%. Median carriage time was reported from 98 days till more than 9 months. For a minority of patients carriage time was more than three years. Prolonged carriage with ESBL-PE was associated with outpatient oral use of antibiotics, urine catheters, chronic wounds, immobility and percutaneous gastrostomy, E. coli phylogroup B2, and CTX-M group 9. In NICU patients, median carriage time was 12.5 months, but carriage persisted after 12 months for 5% of individuals. Prolonged duration was observed for K. pneumonia or K. oxytoca species compared to S. marcensens, antibiotic treatment and caesarian section. Of travelers, 24% carried ESBL-producing E. coli after 3-8 months. Mean carriage time for 22 adopted children from Mali was 9 months. Out of 41 Chinese medical students, 68% remained colonized for 4 months. Results vary greatly and are hard to compare or generalize for many reasons such as small sample size, different definitions for duration, persistence and clearance, absence of molecular information, selection bias, and global differences. A longer duration of carriage with ESBL-PE might influence the risk of carriage with ESBL-PE for the patient itself and transmission to household members and the general population. Routine screening and/or contact restriction is suggested for previously ESBL-PE positive patients. Perhaps focus should be more on prevention of transmission than on clearance, because clearance is hard to accomplish. To estimate duration of carriage with ESBL-PE in the general population, large studies are needed.