Fecal colonization with multidrug-resistant E. coli among healthy infants in rural Bangladesh

Third generation cephalosporins (3GC) are one of the main choices for treatment of infections caused by multidrug-resistant (MDR) Gram-negative bacteria. Due to their overuse, an increasing trend of resistance to 3GC has been observed in developing countries. Here, we describe fecal colonization of 3GC-resistant (3GCr); Escherichia coli; in healthy infants (1-12 months old) living in rural areas of Bangladesh. We found that stool samples of 82% of infants (; n; = 100) were positive for 3GCr; E. coli; with a mean ± standard deviation of 6.21 ± 1.32 log; 10; CFU/g wet weight of stool. 3GCr; E. coli; encompasses an average one third (33%) of the total; E. coli; of stool. Almost 77% (; n; = 63) of these 3GCr; E. coli; were MDR (or resistant to ≥3 classes of antibiotics). Around 90% (; n; = 74) of 3GCr; E. coli; were extended spectrum beta-lactamase (ESBL)-producing in which; bla; CTX-M-group-1; was the predominant (96%,; n; = 71) ESBL-gene followed by; bla; TEM; (41%,; n; = 30) and; bla; OXA-1; (11%,; n; = 8). A significant proportion (26.5%,; n; = 22) of 3GCr; E. coli; was pathogenic, comprising two types, enteroaggregative (EAEC,; n; = 19) and enteropathogenic (EPEC,; n; = 3). Colonization of 3GCr; E. coli; in infant guts was not associated with demographic characteristics such as age, sex, mode of delivery, maternal and infant antibiotic use, disease morbidity, and feeding practices. The high rate of colonization of 3GCr; E. coli; in infants' guts is a serious public health concern which needs immediate attention and warrants further studies to explore the cause.