An observational study in Bangladesh found that fecal carriage of antibiotic-resistant Escherichia coli in children was associated with associated with high levels of arsenic in contaminated water, researchers reported yesterday in PLOS Pathogens.
Previous research in Bangladesh, where arsenic-contaminated groundwater is widespread, has suggested that exposure to arsenic might play a role in the emergence and spread of antibiotic resistance. Arsenic-resistant bacteria have been isolated from various sources, and one study has shown arsenic-induced antibiotic resistance in laboratory conditions. But empirical evidence of the connection is lacking.
To further establish a link between arsenic and antibiotic resistance, researchers from Bangladesh, Switzerland, and the United States collected drinking water and stool samples from children and their mothers in two rural areas of Bangladesh—one with high levels of arsenic in drinking water (Hajiganj) and one with low arsenic contamination (Matlab)—and compared the levels of antibiotic-resistant E coli.
Of the 251 E coli isolates collected from samples both sites, 94% were resistant to at least one antibiotic. The prevalence of antibiotic-resistant E coli was significantly higher in water in Hajiganj (48%) compared to water in Matlab (22%), and among children in Hajiganj (94%) compared to children in Matlab (76%), but not among mothers. In addition, a significantly higher proportion of E coli isolates from Hajiganj were multidrug-resistant (83%) compared to isolates from Matlab (71%), while co-resistance to arsenic and multiple antibiotics was observed in a higher proportion of water (78%) and child stool (100%) isolates in Hajiganj than in water (57%) and children (89%) in Matlab.
The association between arsenic and antibiotic resistance was observed among all E coli isolates from both areas. The odds of arsenic-resistant E coli to be resistant to beta-lactam antibiotics including ampicillin (odds ratio [OR], 3.4: 95% confidence interval [CI], 1.4 to 8.1), cefotaxime (OR, 2.5; 95% CI, 1.2 to 5.3), and ceftriaxone (OR, 3.4; 95% CI, 1.6 to 7.0) were higher compared to that of arsenic-sensitive E coli isolates.
"The positive association detected between arsenic exposure and antibiotic resistance carriage among children in arsenic-affected areas in Bangladesh is an important public health concern that warrants redoubling efforts to reduce arsenic exposure," the study authors wrote.