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Background. Nontuberculous mycobacteria (NTM) are important human pathogens, yet little is known about disease prevalence in the United States. Reports suggest prevalence has increased, particularly in women, but population-based data to substantiate this are lacking. We sought to estimate NTM disease prevalence in Oregon, and describe disease by site, species, and patient demographic characteristics. Methods. We contacted laboratories that performed mycobacterial cultures on Oregon residents in 2005–2006. For each isolate, we obtained source, collection date, species, and patient demographics. We used the microbiologic component of the American Thoracic Society/Infectious Diseases Society of America's pulmonary NTM disease criteria to define cases of pulmonary NTM, and patients with isolates from a normally sterile site were classified as having extrapulmonary disease. Results. We identified 933 patients with ⩾1 NTM isolate. Of these, 527 (56%) met the case definition (annualized prevalence, 7.2 cases per 100,000 persons). Pulmonary cases predominated (5.6 cases per 100,000 persons), followed by skin/soft-tissue cases (0.9 cases per 100,000 persons). Mycobacterium avium complex was the most common species identified in pulmonary cases (4.7 cases per 100,000 persons). Pulmonary disease prevalence was significantly higher in women (6.4 cases per 100,000 persons) than men (4.7 cases per 100,000 persons) and was highest in persons aged >50 years (15.5 cases per 100,000 persons). Conclusions. NTM are frequently isolated from Oregon residents; more than one-half of all isolates likely represent true disease. Pulmonary NTM is most common among elderly women, and M. avium causes most disease. Future efforts to monitor disease trends should be undertaken, and efforts made to validate the use of the ATS/IDSA microbiologic criteria alone to predict pulmonary NTM disease.

Carbapenem-resistant Pseudomonas aeruginosa (CRPA) producing the Verona integron‒encoded metallo-β-lactamase (VIM) are highly antimicrobial drug-resistant pathogens that are uncommon in the United States. We investigated the source of VIM-CRPA among US medical tourists who underwent bariatric surgery in Tijuana, Mexico. Cases were defined as isolation of VIM-CRPA or CRPA from a patient who had an elective invasive medical procedure in Mexico during January 2018‒December 2019 and within 45 days before specimen collection. Whole-genome sequencing of isolates was performed. Thirty-eight case-patients were identified in 18 states; 31 were operated on by surgeon 1, most frequently at facility A (27/31 patients). Whole-genome sequencing identified isolates linked to surgeon 1 were closely related and distinct from isolates linked to other surgeons in Tijuana. Facility A closed in March 2019. US patients and providers should acknowledge the risk for colonization or infection after medical tourism with highly drug-resistant pathogens uncommon in the United States.

Background: Infections lead to high mortality among patients on chronic dialysis; knowledge of multi-drug resistant infections is limited. The Centers for Disease Control and Prevention’s Emerging Infections Program (EIP) conducts laboratory- and population-based surveillance for carbapenem-resistant Enterobacterales (CRE) in 10 U.S. sites and carbapenem-resistant Acinetobacter baumannii (CRAB) in 9 U.S. sites. We investigated clinical characteristics, healthcare exposures, and outcomes of CRE and CRAB cases in persons on chronic dialysis from 2016-2021. Methods: Among EIP catchment-area residents on chronic dialysis, we defined a CRE case as the first isolation of Escherichia coli, Enterobacter cloacae complex, Klebsiella aerogenes (formerly Enterobacter aerogenes), Klebsiella oxytoca, Klebsiella pneumoniae, or Klebsiella variicola resistant to any carbapenem, from a normally sterile site or urine in a 30-day period. A CRAB case was defined as the first isolation of Acinetobacter baumannii complex resistant to any carbapenem (excluding ertapenem), from a normally sterile site or urine (or lower respiratory tract or wound since 2021) in a 30-day period. Medical records were reviewed. A case was considered colonized if the case culture had no associated infection type or colonization was documented in the medical record. Descriptive analyses, including analyses stratified by pathogen, were conducted. Results: Among 426 cases, 314 were CRE, and 112 were CRAB; most cases were male (235, 55.2%), Black (229, 53.8%), and 51-80 years old (320, 75.1%) (Table). An infection was associated with 363 (85.2%) case cultures; bloodstream infections (148; 40.8%), urinary tract infections (134; 36.9%), and pneumonia (17; 4.7%) were the most frequent. Overall, most cases had documented healthcare exposures (excluding outpatient dialysis) in the year before incident specimen collection, including: 366 (85.9%) hospitalizations, 235 (55.2%) surgeries, 209 (49.1%) long-term care facility stays, 54 (12.7%) long-term acute care facility stays. Additionally, 125 (29.3%) had an intensive care unit admission within the 7 days before incident specimen collection. Compared to CRE cases, a higher proportion of CRAB cases (a) had a long-term care facility stay (82/112 [73.2%] versus 127/314 [40.5%], P<.0001) or hospitalization (103/112 [92%] versus 263/314 [83.8%], P = .03) within the preceding year and (b) died within 30 days of incident specimen collection (40/112 [35.7%] versus 64/314 [20.4%], P = .001). Discussion: Among CRE and CRAB cases in persons on chronic dialysis, healthcare exposures were common, and mortality was high. Additional efforts to better describe the burden of these organisms and associated risk factors in the dialysis population are needed for tailoring infection prevention strategies to this vulnerable.

A 12-month, population-based, case-control study of Campylobacter infections was conducted at Foodborne Disease Active Surveillance Network surveillance areas during 1998–1999. Of 858 Campylobacter isolates tested for antimicrobial susceptibility to the fluoroquinolone ciprofloxacin, 94 (11%) were resistant. Travel outside of the United States was reported by 27 (42%) of 64 patients with fluoroquinolone-resistant Campylobacter infection and by 51 (9%) of 582 patients with fluoroquinolone-susceptible Campylobacter infection (odds ratio [OR], 7.6; 95% confidence interval [CI], 4.3–13.4). When patients with domestically acquired fluoroquinolone-resistant Campylobacter infection were compared with matched healthy control subjects in a multivariate analysis, those infected were 10 times more likely to have eaten chicken or turkey cooked at a commercial establishment (18 [55%] of 33 case patients vs. 7 [21%] of 33 controls; matched OR, 10.0; 95% CI, 1.3–78). Although travel outside of the United States was associated with fluoroquinolone-resistant Campylobacter infection, most infections among study participants were domestically acquired. This study provides additional evidence that poultry is an important source of domestically acquired fluoroquinolone-resistant Campylobacter infection. Control measures should include efforts to improve food handling in commercial establishments.

Abstract Background We described changes in 2016─2020 carbapenem-resistant Enterobacterales (CRE) incidence rates in 7 US sites that conduct population-based CRE surveillance. Methods An incident CRE case was defined as the first isolation of Escherichia coli, Klebsiella spp., or Enterobacter spp. resistant to ≥1 carbapenem from a sterile site or urine in a surveillance area resident in a 30-day period. We reviewed medical records and classified cases as hospital-onset (HO), healthcare-associated community-onset (HACO), or community-associated (CA) CRE based on healthcare exposures and location of disease onset. We calculated incidence rates using census data. We used Poisson mixed effects regression models to perform 2016─2020 trend analyses, adjusting for sex, race/ethnicity, and age. We compared adjusted incidence rates between 2016 and subsequent years using incidence rate ratios (RRs) and 95% confidence intervals (CIs). Results Of 4996 CRE cases, 62% were HACO, 21% CA, and 14% HO. The crude CRE incidence rate per 100 000 was 7.51 in 2016 and 6.08 in 2020 and was highest for HACO, followed by CA and HO. From 2016 to 2020, the adjusted overall CRE incidence rate decreased by 24% (RR, 0.76 [95% CI, .70–.83]). Significant decreases in incidence rates in 2020 were seen for HACO (RR, 0.75 [95% CI, .67–.84]) and CA (0.75 [.61–.92]) but not for HO CRE. Conclusions Adjusted CRE incidence rates declined from 2016 to 2020, but changes over time varied by epidemiologic class. Continued surveillance and effective control strategies are needed to prevent CRE in all settings. From 2016 to 2020, the adjusted overall incidence rate of carbapenem-resistant Enterobacterales (CRE) across 7 US sites declined; however, changes over time varied by epidemiologic class.

Background: Due to limited therapeutic options and potential for spread, carbapenem-resistant Enterobacteriaceae (CRE)-producing New Delhi metallo-β-lactamases (NDMs) are a public health priority. We investigated the epidemiology of NDM-producing CRE reported to the CDC to clarify its distribution and relative prevalence. Methods: The CDC’s Antibiotic Resistance Laboratory Network supports molecular testing of CRE for 5 carbapenemases nationally. Although KPC is the most common carbapenemase in the United States, non-KPC carbapenemases are a growing concern. We analyzed CRE with any of 4 non-KPC plasmid-mediated carbapenemases (NDM, VIM, IMP, or OXA-48 type) isolated from specimens collected from January 1, 2017, through June 30, 2019; only a patient’s first isolate per organism–carbapenemase combination was included. We excluded isolates from specimen sources associated with colonization screening (eg, perirectal). We compared the proportion of NDM-producing CRE to all non-KPC–producing CP-CRE between period A (January to June 2018) and period B (January to June 2019). Health departments and the CDC collected additional exposure and molecular information in selected states to better describe current NDM-producing CRE epidemiology. Results: Overall, 47 states reported 1,013 non–KPC-producing CP-CRE (range/state, 1–109 isolates; median, 11 isolates); 46 states reported 631 NDM-producing CRE (range/state, 1–84; median, 6). NDM-producing CRE increased quarterly from the third quarter of 2018 through the second quarter of 2019; CP-CRE isolates with other non-KPC carbapenemases remained stable (Fig. 1). In period A, 124 of 216 emerging CP-CRE had NDM (57.1%), compared with 255 of 359 emerging CP-CRE (71.0%) during period B ( P = .1179). Among NDM-producing CRE, the proportion of Enterobacter spp increased from 10.5% in 2018 to 18.4% in 2019 ( P = .0467) (Fig. 2). In total, 18 states reported more NDM-producing CRE in the first 6 months of 2019 than in all of 2018. Connecticut, Ohio, and Oregon were among states that conducted detailed investigations; these 3 states identified 24 NDM-producing CRE isolates from 23 patients in period B. Overall, 5 (21.7%) of 22 patients with history available traveled internationally ≤12 months prior to culture; 17 (73.9%) acquired NDM-producing CRE domestically. Among 15 isolates sequenced, 8 (53.3%) carried NDM-5 (6 E. coli , 1 Enterobacter spp and 1 Klebsiella spp) and 7 (46.7%) carried NDM-1 (6 Enterobacter spp and 1 Klebsiella spp). Species were diverse; no single strain type was shared by >2 isolates. Conclusions: Detection of NDM-producing CRE has increased across the AR Lab Network. Among states with detailed information available, domestic acquisition was common, and no single variant or strain predominated. Aggressive public health response and further understanding of current US NDM-CRE epidemiology are needed to prevent further spread. Disclosures: None Funding: None

Background: Carbapenem-resistant Pseudomonas aeruginosa (CRPA) is a frequent cause of healthcare-associated infections (HAIs). The CDC Emerging Infections Program (EIP) conducted population and laboratory-based surveillance of CRPA in selected areas in 8 states from August 1, 2016, through July 31, 2018. We aimed to describe the molecular epidemiology and mechanisms of resistance of CRPA isolates collected through this surveillance. Methods: We defined a case as the first isolate of P. aeruginosa resistant to imipenem, meropenem, or doripenem from the lower respiratory tract, urine, wounds, or normally sterile sites identified from a resident of the EIP catchment area in a 30-day period; EIP sites submitted a systematic random sample of isolates to CDC for further characterization. Of 1,021 CRPA clinical isolates submitted, 707 have been sequenced to date using an Illumina MiSeq. Sequenced genomes were classified using the 7-gene multilocus sequence typing (MLST) scheme, and a core genome MLST (cgMLST) scheme was used to determine phylogeny. Antimicrobial resistance genes were identified using publicly available databases, and chromosomal mechanisms of carbapenem resistance were determined using previously validated genetic markers. Results: There were 189 sequence types (STs) among the 707 sequenced genomes (Fig. 1). The most frequently occurring were high-risk clones ST235 (8.5%) and ST298 (4.7%), which were found across all EIP sites. Carbapenemase genes were identified in 5 (<1%) isolates. Overall, 95.6% of the isolates had chromosomal mutations associated with carbapenem resistance: 93.2% had porinD-associated mutations that decrease membrane permeability to the drugs; 24.8% had mutations associated with overexpression of the multidrug efflux pump MexAB-OprM; and 22.9% had mutations associated with overexpression of the endogenous β-lactamase ampC . More than 1 such chromosomal resistance mutation type was present in 37.8% of the isolates. Conclusions: The diversity of the sequence types demonstrates that HAIs caused by CRPA can arise from a variety of strains and that high-risk clones are broadly disseminated across the EIP sites but are a minority of CRPA strains overall. Carbapenem resistance in P. aeruginosa was predominantly driven by chromosomal mutations rather than acquired mechanisms (ie, carbapenemases). The diversity of the CRPA isolates and the lack of carbapenemase genes suggest that this ubiquitous pathogen can readily evolve chromosomal resistance mechanisms, but unlike carbapenemases, these cannot be easily spread through horizontal transfer. Funding: None Disclosures: None

Background: Automated testing instruments (ATIs) are commonly used by clinical microbiology laboratories to perform antimicrobial susceptibility testing (AST), whereas public health laboratories may use established reference methods such as broth microdilution (BMD). We investigated discrepancies in carbapenem minimum inhibitory concentrations (MICs) among Enterobacteriaceae tested by clinical laboratory ATIs and by reference BMD at the CDC. Methods: During 2016–2018, we conducted laboratory- and population-based surveillance for carbapenem-resistant Enterobacteriaceae (CRE) through the CDC Emerging Infections Program (EIP) sites (10 sites by 2018). We defined an incident case as the first isolation of Enterobacter spp ( E. cloacae complex or E. aerogenes ), Escherichia coli , Klebsiella pneumoniae , K. oxytoca , or K. variicola resistant to doripenem, ertapenem, imipenem, or meropenem from normally sterile sites or urine identified from a resident of the EIP catchment area in a 30-day period. Cases had isolates that were determined to be carbapenem-resistant by clinical laboratory ATI MICs (MicroScan, BD Phoenix, or VITEK 2) or by other methods, using current Clinical and Laboratory Standards Institute (CLSI) criteria. A convenience sample of these isolates was tested by reference BMD at the CDC according to CLSI guidelines. Results: Overall, 1,787 isolates from 112 clinical laboratories were tested by BMD at the CDC. Of these, clinical laboratory ATI MIC results were available for 1,638 (91.7%); 855 (52.2%) from 71 clinical laboratories did not confirm as CRE at the CDC. Nonconfirming isolates were tested on either a MicroScan (235 of 462; 50.9%), BD Phoenix (249 of 411; 60.6%), or VITEK 2 (371 of 765; 48.5%). Lack of confirmation was most common among E. coli (62.2% of E. coli isolates tested) and Enterobacter spp (61.4% of Enterobacter isolates tested) (Fig. 1A), and among isolates testing resistant to ertapenem by the clinical laboratory ATI (52.1%, Fig. 1B). Of the 1,388 isolates resistant to ertapenem in the clinical laboratory, 1,006 (72.5%) were resistant only to ertapenem. Of the 855 nonconfirming isolates, 638 (74.6%) were resistant only to ertapenem based on clinical laboratory ATI MICs. Conclusions: Nonconfirming isolates were widespread across laboratories and ATIs. Lack of confirmation was most common among E. coli and Enterobacter spp. Among nonconfirming isolates, most were resistant only to ertapenem. These findings may suggest that ATIs overcall resistance to ertapenem or that isolate transport and storage conditions affect ertapenem resistance. Further investigation into this lack of confirmation is needed, and CRE case identification in public health surveillance may need to account for this phenomenon. Funding: None Disclosures: None

OBJECTIVE To determine the scope, source, and mode of transmission of a multifacility outbreak of extensively drug-resistant (XDR) Acinetobacter baumannii. DESIGN Outbreak investigation. SETTING AND PARTICIPANTS Residents and patients in skilled nursing facilities, long-term acute-care hospital, and acute-care hospitals. METHODS A case was defined as the incident isolate from clinical or surveillance cultures of XDR Acinetobacter baumannii resistant to imipenem or meropenem and nonsusceptible to all but 1 or 2 antibiotic classes in a patient in an Oregon healthcare facility during January 2012-December 2014. We queried clinical laboratories, reviewed medical records, oversaw patient and environmental surveillance surveys at 2 facilities, and recommended interventions. Pulsed-field gel electrophoresis (PFGE) and molecular analysis were performed. RESULTS We identified 21 cases, highly related by PFGE or healthcare facility exposure. Overall, 17 patients (81%) were admitted to either long-term acute-care hospital A (n=8), or skilled nursing facility A (n=8), or both (n=1) prior to XDR A. baumannii isolation. Interfacility communication of patient or resident XDR status was not performed during transfer between facilities. The rare plasmid-encoded carbapenemase gene bla OXA-237 was present in 16 outbreak isolates. Contact precautions, chlorhexidine baths, enhanced environmental cleaning, and interfacility communication were implemented for cases to halt transmission. CONCLUSIONS Interfacility transmission of XDR A. baumannii carrying the rare blaOXA-237 was facilitated by transfer of affected patients without communication to receiving facilities. Infect Control Hosp Epidemiol 2017;38:1335-1341.

Nontuberculous mycobacteria (NTM), ubiquitous in soil and water, usually infect immunocompromised persons. However, even healthy persons are susceptible to infection through percutaneous inoculation. Although 77% of NTM diseases manifest as primarily pulmonary illnesses (1), NTM also infect skin, bones, joints, the lymphatic system, and soft tissue. NTM infections can have incubation periods that exceed 5 years (2), often require prolonged treatment, and can lead to sepsis and death. Extrapulmonary NTM outbreaks have been reported in association with contaminated surgical gentian violet (3), nail salon pedicures (4), and tattoos received at tattoo parlors (5), although few surveillance data have been available for estimating the public health burden of NTM.* On January 1, 2014, the Oregon Health Authority designated extrapulmonary NTM disease a reportable condition. To characterize extrapulmonary NTM infection, estimate resources required for surveillance, and assess the usefulness of surveillance in outbreak detection and investigation, 2014-2016 extrapulmonary NTM surveillance data were reviewed, and interviews with stakeholders were conducted. During 2014-2016, 134 extrapulmonary NTM cases (11 per 1 million persons per year) were reported in Oregon. The age distribution was bimodal, with highest incidence among persons aged <10 years (20 per 1 million persons per year) and persons aged 60-69 years (18 per 1 million persons per year). The most frequently reported predisposing factors (occurring within 14-70 days of symptom onset) were soil exposure (41/98; 42%), immunocompromised condition (42/124; 34%), and surgery (32/120; 27%). Overall, 43 (33%) patients were hospitalized, 18 (15%) developed sepsis, and one (0.7%) died. Surveillance detected or helped to control two outbreaks at low cost. Jurisdictions interested in implementing extrapulmonary NTM surveillance can use the Council of State and Territorial Epidemiologists (CSTE) standardized case definition (6) for extrapulmonary NTM reporting or investigative guidelines maintained by the Oregon Health Authority (7).