Bird droppings are unsightly and often inconvenient, depending on where they land. They also carry some health risks, and new research from Rice University unveiled more threats associated with droppings from our feathered friends and neighbors. Unfortunately, antibiotic resistance is one of these risks.
Environmental engineers from Rice University led the study, and it was published last week in Environmental Pollution. According to an article from Rice University regarding the research, prior studies determined that antibiotic-resistant genes (ARGs) and bacteria (ARBs) from birds “can be transferred to humans through swimming, contact with feces, or impacted soil or inhalation of aerosolized fecal particles.” The article states that this particular study aimed to “quantify the abundance, diversity, and seasonal persistence of ARGs.”
To achieve this goal, the researchers compared samples species found around Houston during winter and summer to samples from poultry and livestock. According to the article from Rice University, the results showed that the ARGs in all species “encoded significant resistance to tetracycline, beta-lactam, and sulfonamide antibiotics.” The report also states that the team was surprised by the high levels of ARGs compared to those of poultry that are occasionally fed antibiotics. Additionally, the article reports that intl1 was five times more abundant in wild birds than farm animals.
Pedro Alvarez, co-author and environmental engineer, told Rice University reporters, “our results indicate that wild birds are an overlooked but potentially important reservoir of antimicrobial resistance genes.” He does clarify that because of the low frequency of human contact, while the transmission is possible, it is improbable.
The study examined crows, ducks, and gulls. The Rice University article reports that of these species, crows showed significantly lower levels of ARGs during the summer. Rice graduate student Ruonan Sun attributes this to their ecological niche, foraging patterns, and gut microbiome. In all the feces of three species, the researchers discovered “opportunistic pathogens,” such as those responsible for urinary tract and respiratory infections, as well as bacteria known to cause food poisoning in winter samples. They report that winter feces, in general, had higher levels of “bad bacteria,” likely caused by lower sunlight, differences in moisture levels, and temperature.
Pingfeng Yu, postdoctoral research associate and lead author, told Rice reporters that this study will help raise awareness about the threat of urban bird droppings and that regular cleanings should help mitigate serious risks.