The Centers for Disease Control and Prevention’s Antibiotic Resistance (AR) Lab Network has detected 221 instances of bacteria with especially rare resistance genes in the United States, according to a Vital Signs report published online and expanded upon in CDC’s MMWR Weekly.
The MMWR Weekly report, “Containment of Novel Multidrug-Resistant Organisms and Resistance Mechanisms,” which goes deeper into the science behind the issue, shows that in 9 months, in all states and Puerto Rico, health department workers in the AR lab network tested 5,776 samples of highly resistant bacteria, according to Anne Schuchat, MD, principal deputy director of the CDC. These bacteria were immediately tested for unusual resistance – “those genes that were highly resistant, or rare, with special resistance that could spread,” she said.
“Of the 5,776, about 1 in 4 of the bacteria had a gene that helped it spread its resistance. And there were 221 instances of an especially rare resistance gene,” she added. This prompted intense screening, revealing “that 1 in 10 tests were also positive. Meaning the unusual resistance may have spread to other patients. And could have continued spreading if left undetected.”
The report looked at carbapenem-resistant Enterobacteriaceae (CRE) and Enterobacteriaceae with extended-spectrum beta-lactamases (ESBL) infection data from the National Healthcare Safety Network from 2006-2015 to calculate changes in the year over year proportions of these infections and how an enhanced detection and control strategy curbs carbapenem resistance.
This strategy includes components such as timely implementation of appropriate infection control measures, conducting a health care and contact investigation with follow-up, and implementing a system to ensure adherence to infection control measures.
“With independent, or single facility approaches to control spread, a dangerous type of unusual resistance in Enterobacteriaceae [ESBL phenotype] decreased by about 2% per year [(risk ratio [RR] = 0.98, P less than .001)].” With a more aggressive approach, using guidance such as CDC’s CRE toolkit, released in 2009, another type of unusual resistance [CRE] in the same bacteria (Enterobacteriaceae) decreased by nearly 15% per year (RR = 0.85, P less than .01).
The difference may be due in part to the more directed response utilized to slow the spread of the “nightmare bacteria,” once it was identified, said Dr. Schuchat.
These results show massive promise even if only partially effective, specifically for CRE.