Lab Matters Summer 2019 - Page 10

FEATURE for 14 states plus Puerto Rico and surge capacity nationwide. In 2017-2018, the laboratory examined over 9,600 specimens for carbapenem resistance and detected or confirmed over 300 highly resistant Acinetobacter isolates, over 1,100 resistant Pseudomonas isolates and almost 3,500 carbapenem-resistant Enterobacteriaceae isolates. Among other successes, Burks said his scientific team employed a new PCR method to identify three new AR gene groups in Acinetobacter. “The number of Acinetobacter specimens [we receive] seems to be holding steady,” he said, “but resistance is surprisingly high—about 70% positive for one of the three genes Tennessee identified.” But because there is no reliable pre-AR Lab Network assessment of carbapenem resistance in Acinetobacter, Burks said, “We don’t know if the rate is increasing or if it was already that high.” Under the direction of Henrietta Hardin, MPA, MT(ASCP), the facility’s general bacteriology manager, the Tennessee laboratory is also one of four regional AR Lab Network laboratories testing for resistance in Neisseria gonorrhoeae (the so-called GC AR Lab Network). The bacteriology team tests specimens from high-prevalence sites across the country that participate in CDC’s Gonococcal Isolates Surveillance Program (GISP), enhanced GISP or Strengthening US Response to Resistant Gonorrhea program. Since the laboratory joined the GC AR Lab Network in spring 2017, it has analyzed over 5,500 isolates for susceptibility to seven antibiotics using agar dilution plates produced in-house. Overall, 7% of isolates have exhibited drug resistance. Hardin said her team is now involved in setting susceptibility “breakpoints” for new drugs, like gentamicin, which will hopefully prove effective against some drug-resistant gonorrhea strains. Within the state of Tennessee itself, Kainer said the biggest AR threat is “an oldie” that is making a comeback: methicillin-resistant Staphylococcus aureus (MRSA). She said, “We have seen very significant increases particularly among the younger population and more among females.” Between 2014 and 2018, the number of MRSA bloodstream infections reported by Tennessee hospitals jumped from 2,123 to 3,277—a 54% increase. “The epidemiology of [MRSA transmission] is changing,” said Kainer. “It’s now likely to be driven by the opioid epidemic—users injecting with tainted needles, syringes or other paraphernalia. They often get these MRSA infections along with endocarditis. Those are very serious, very expensive, high-mortality conditions.” In fact, one-year mortality for hospital-onset MRSA bloodstream infection in Tennessee runs about 50%. On the flip side, Kainer said, CPOs carrying the KPC gene have become notably rarer in Tennessee. She said, “We attribute that to improved infection control and environmental cleaning in healthcare settings.” And those improvements she attributes directly to CDC’s stepped-up investment in AR control. Before the CARB plan and associated state funding, Kainer said, “We didn’t have laboratory capacity for rapid [AR] detection and identification, and we didn’t have the public health infrastructure on the epi and infection control side.” Today, a single case of CPO infection in a Tennessee hospital triggers laboratory testing to identify the infectious organism and AR gene, sometimes supplemented by more detailed characterization, such as whole genome sequencing. In addition, Kainer’s staff assesses the facility’s infection control practices—hand hygiene, environmental cleaning, use of personal protective equipment and the like—and collects rectal swabs from potentially exposed patients as part of a point prevalence survey to determine whether transmission has occurred. If laboratory testing shows CPO colonization in other patients, further recommendations are made. “We continue these point prevalence surveys every two weeks until we get two consecutive rounds of negative transmission,” said Kainer. “Having the laboratory capacity to process these colonization swabs is a huge thing. The whole aim here is timely data to allow us to take the appropriate infection control and public health actions. It’s literally a game-changer.” Brittany O’Brien and Rokebul Anower review results from the real-time PCR developed for Candida auris. Photo: Wadsworth Center 8 LAB MATTERS Summer 2019 PublicHealthLabs @APHL