This new paper may be of interest:
Abstract:
Widespread prevalence of multidrug and pandrug-resistant bacteria has prompted substantial concern over the global dissemination of antibiotic resistance genes (ARGs). Environmental compartments can behave as genetic reservoirs and hotspots, wherein resistance genes can accumulate and be laterally transferred to clinically relevant pathogens. In this work, we explore the ARG copy quantities in three environmental media distributed across four cities in California and demonstrate that there exist city-to-city disparities in soil and drinking water ARGs. Statistically significant differences in ARGs were identified in soil, where differences in blaSHV gene copies were the most striking; the highest copy numbers were observed in Bakersfield (6.0 × 10–2copies/16S-rRNA gene copies and 2.6 × 106 copies/g of soil), followed by San Diego (1.8 × 10–3copies/16S-rRNA gene copies and 3.0 × 104 copies/g of soil), Fresno (1.8 × 10–5 copies/16S-rRNA gene copies and 8.5 × 102 copies/g of soil), and Los Angeles (5.8 × 10–6 copies/16S-rRNA gene copies and 5.6 × 102 copies/g of soil). In addition, ARG copy numbers in the air, water, and soil of each city are contextualized in relation to globally reported quantities and illustrate that individual genes are not necessarily predictors for the environmental resistome as a whole.
Basically they used qPCR to examine abundance of various antibiotic resistance genes across samples.
Nothing seems exceptionally striking to me but still of possible interest.
Now – the Press Release from UCLA on the other hand. That is exceptional. But not in a good way.
The lead for the PR is awful. Just plain awful.
The anxiety over antibiotic-resistant superbugs, which are responsible for 23,000 deaths a year in the United States, is likely to grow in California, following the recent discovery by UCLA researchers of high levels of antibiotic-resistant genes in parks in four cities.
So basically they are saying “you should be anxious over this”. Wow. Fearmonger much. And to be honest, no, you should not be anxious over this. This is a limited study with unclear implications and little to compare to.
Amazingly, later in the PR they tell everyone to not be afraid.
Jennifer Jay, a professor of environmental engineering at UCLA and one of the paper’s authors, stressed that although the findings are significant, it’s not time to panic.
and
“We don’t want to sound alarm bells and have people afraid that they’d be breathing ARGs while they’re in the shower,” Jay said.
The real issue here is that the data presented in the paper does not actually tell us whether there is anything new going on here or anything to fear. Maybe there is. Actually, I think we certainly should be more and more worried about antibiotic resistance genes in the environment. But the data in this paper doesn’t really get at that. They write:
However, the range of values seen in this study is wide enough to be inclusive of many values reported in the aforementioned studies.
So basically – the levels in these CS cities may or may not be higher than that seen in other samples in other studies. They do state that it seems that their water samples showed higher levels than in other water samples, especially LA drinking water:
However, nearly all drinking water samples obtained from Los Angeles, CA, exceed these reported values by nearly an order of magnitude.
But it is really important to realize that it is not simple to compare to these other studies done by other groups with somewhat different methods. Certainly, this is important to keep looking at. But it is ridiculous for UCLA to lead off their PR about this work with fear mongering and predicting anxiety when the results do not provide any clear evidence that there is an actual problem here. Again, yes we should be vigilant and worried about antibiotic resistance genes. And yes, we should reduce antibiotic usage in every way we can. But no, it is not clear if there is anything specific to get anxious about based on this study. And encouraging that anxiety is dangerous.