Lab Matters Summer 2019 - Page 9

FEATURE recommend doing them if we can’t treat any infections that might come up.” agencies to “accelerate response to antibiotic resistance,” including: In 2014, the World Health Organization called AR “a problem so serious that it threatens the achievements of modern medicine.” • Improving antibiotic stewardship in healthcare settings, including cutting antibiotic use by 50% in outpatient settings and 20% in inpatient settings by 2020 Indeed, Craig said reservoirs of AR are now so great, it is no longer sufficient to simply stop misusing and overusing antibiotics: “Even if we have perfect antibiotic prescribing and use, AR would still be a problem, largely because of the transmission of [existing] resistant pathogens.” These pathogens may colonize individuals who never become symptomatic. Or they may persist in animal hosts, in healthcare facilities or in the broader environment (for example, after being discharged in hospital waste). • Preventing the spread of AR threats • Eliminating the sub-therapeutic use of medically important antibiotics in food animals • Expanding surveillance for AR bacteria in people and animals • Creating a regional public health laboratory network • Establishing an AR specimen repository and genetic sequence database to facilitate development of new diagnostic tests and pathogen-specific treatments. Bacteria containing the AR gene NDM-1 have been found in water pools in New Delhi streets and in High Arctic soils in Norway’s Svalbard archipelago, demonstrating just how widely dispersed the organisms are. So far, Craig said, one of CDC’s biggest AR achievements, “if not the biggest achievement,” is the founding of the regional AR Lab Network. And because AR genes are often found on mobile genetic elements called plasmids, they can be transferred from one microorganism to another without any antibiotic exposure. So, for example, KPC—the most common AR gene found in carbapenemase-producing organisms (CPOs) in the US—may be transferred from Klebsiella to Salmonella to CRPA. All 56 AR Lab Network members perform basic testing, such as antibiotic susceptibility testing and detection of carbapenemases (enzymes that hydrolyze certain antibiotics) in Enterobacteriaceae and Pseudomonas aeruginosa isolates. In 2013, CDC released an AR threat report listing 18 microbes, collectively responsible for more than two million illnesses and at least 23,000 deaths in the US each year. However, the report was written before the launch of the AR Lab Network, when data were less complete. Craig said an updated report due out later this year will note that, “as we expected, the burden of AR infections is more than we estimated previously; for some pathogens, significantly more.” The AR Lab Network— “A Game-changer” Two years after the threat report came out, the Obama Administration released its National Action Plan for Combating Antibiotic-Resistant Bacteria. The so-called “CARB” plan directs federal PublicHealthLabs @APHL In addition, the seven regional AR Lab Network members perform molecular testing to detect colonization of CPOs in people potentially exposed by an index case; fungal susceptibility testing of Candida species; colonization screening for Candida auris; and detection and characterization of emerging threats, such as mcr-1, a bacterial gene that confers plasmid-mediated resistance to colistin (the drug-of-last-resort prescribed for Tamika Capone). AR Lab Network laboratories also provide isolates for the new CDC/FDA AR Isolate Bank and for federal whole genome sequencing projects. The TDH Division of Laboratory Services— the state public health laboratory—is the Southeast Regional AR Lab Network Laboratory that provides core AR Lab Network testing for six states plus Puerto Rico, expanded drug susceptibility testing Urgent Threats • Clostridium difficile • Carbapenem-resistant Enterobacteriaceae • Drug-resistant Neisseria gonorrhoeae Serious Threats • • • • • • • • • • • • Multidrug-resistant Acinetobacter Drug-resistant Campylobacter Fluconazole-resistant Candida Extended spectrum ß-lactamase producing Enterobacteriaceae Vancomycin-resistant Enterococcus Multidrug-resistant Pseudomonas aeruginosa Drug-resistant non-typhoidal Salmonella Drug-resistant Salmonella Typhi Drug-resistant Shigella Methicillin-resistant Staphylococcus aureus Drug-resistant Streptococcus pneumoniae Drug-resistant tuberculosis Concerning Threats • Vancomycin-resistant Staphylococcus aureus • Erythomycin-resistant Group A Streptococcus • Clindamycin-resistant Group B Streptococcus Source: CDC. Antibiotic Resistance Threats in the United States, 2013 Summer 2019 LAB MATTERS 7