Tattoo-Associated Cutaneous Mycobacterium mageritense Infection: A Case Report and Brief Review of the Literature

There have been increasing reports of tattoo-associated mycobacterial infections in recent years, with a number of outbreaks documented worldwide. This has therefore become a public health concern. Nontuberculous mycobacteria (NTM) are capable of producing skin and soft tissue infections typically via inoculation during surgery, trauma, and cosmetic procedures. We present a case of tattoo-associated cutaneous infection caused by <i>Mycobacterium mageritense</i>, a rare species of rapidly growing NTM. A 25-year-old man developed a rash on his left lower leg 4 weeks after he underwent professional tattooing. A skin swab identified <i>M</i>. <i>mageritense</i> complex. Based on susceptibility testing, a course of oral ciprofloxacin and trimethoprim/sulfamethoxazole was initiated, with significant improvement observed after 5 weeks. We speculate that the mechanism of inoculation was a result of either the artist using nonsterile water to dilute black ink to gray or from use of contaminated prediluted gray ink. The Therapeutic Goods Administration does not have regulatory authority over the sterility of tattoo inks or practices in Australia. Instead, tattoo practices are regulated by local government jurisdictions. Because of the variability seen in clinical presentation and challenges associated with organism identification, a high index of suspicion is required to diagnose mycobacterial infections. Infection caused by NTM should be considered in the differential diagnosis of tattoo-associated dermatological complications, particularly in patients who have chronic lesions, negative bacterial cultures, and fail to respond to standard antibiotic therapy. Mandatory regulations for safe tattoo practices should be considered to prevent outbreaks and ensure public safety.

Impact of Direct From Blood Culture Identification of Pathogens Paired With Antimicrobial Stewardship Interventions in a Pediatric Hospital

OBJECTIVE Identification of organisms directly from positive blood culture by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has the potential for improved clinical outcomes through earlier organism identification and shorter time to appropriate clinical intervention. The uses of this technology in pediatric patients and its impact in this patient population have not been well described. METHODS Direct from positive blood culture organism identification via MALDI-TOF was implemented in September 2019. A quality improvement project was performed to assess its impact on admissions for contaminant blood cultures and time to effective and optimal antimicrobials and clinical decision-making. A pre- and post-implementation retrospective review for consecutive September through February time periods, was conducted on patients with positive monomicrobial blood cultures. Statistics were evaluated using Mann-Whitney U and χ2 tests. RESULTS One hundred nineteen patients with 131 unique blood cultures (65 in pre- and 66 in post-implementation) were identified. Time to identification was shorter, median 35.4 hours (IQR, 22.7–54.3) versus 42.3 hours (IQR, 36.5–49) in post- and pre-groups, respectively (p = 0.02). Patients were less likely to be admitted for a contaminated blood culture in the post-implementation, 26% versus 11% in the pre-implementation (p = 0.03) group. In patients treated for bacteremia, there was a shorter time to optimal therapy from Gram stain reporting in the post-implementation (median 42.7 hours [IQR, 27.2–72]) versus pre-implementation (median 60.8 hours [IQR, 42.9–80.6]) (p = 0.03). CONCLUSIONS Direct from positive blood culture identification by MALDI-TOF decreased time to effective and optimal antimicrobials and decreased unnecessary admission in pediatric patients for contaminated blood cultures.

1024. Using DOOR-MAT to Theoretically Compare Three Rapid Diagnostic Tests for Gram-Negative Bloodstream Infections in Immunocompromised Patients

Background Molecular rapid diagnostic tests (RDTs) for bloodstream infections (BSI) utilize a variety of technologies and differ substantially in organisms and resistance mechanisms detected. RDT platforms decrease time to optimal antibiotics; however, data on RDTs in special populations, such as immunocompromised are extremely limited. This study aimed to compare theoretical changes in antibiotics based on differences in panel identification of organisms and resistance targets among three commercially available RDT panels. Methods Retrospective cohort of immunocompromised patients treated for gram-negative BSI at University of Maryland Medical Center from January 2018 to September 2020. Immunocompromised was defined as active hematologic or solid tumor malignancy at time of BSI diagnosis, history of hematopoietic stem cell transplantation (HSCT) or solid organ transplantation (SOT), or absolute neutrophil count (ANC) &lt; 1000 cells/mm3 at any time 30 days prior to BSI diagnosis. Verigene BC-GN was performed as standard of care. GenMark ePlex BCID and BioFire FilmArray BCID 2 results were assigned based on respective identifiable organism panels. An infectious diseases clinician blinded to final antimicrobial susceptibility testing (AST) results used RDT results to assign antibiotic treatments for each platform. Decisions were referenced against a priori DOOR-MAT matrices. A partial credit scoring system (0 to 100) was applied to each decision based on final AST results. The mean and standard deviation (SD) were compared across panels using One-Way Repeated Measures ANOVA with modified Bonferroni for multiple comparisons. Results A total of 146 patients met inclusion. Baseline characteristics are summarized in Table 1. The mean (SD) DOOR-MAT scores for the three RDT panels were: 86.1 (24.4) Verigene BC-GN vs. 88.5 (22.2) GenMark BCID vs. 87.2 (24.4) BioFire BCID 2. There was no statistically significant difference between the panels for DOOR-MAT score (P=0.6). Table 1. Baseline Patient Characteristics and Organism Identification Conclusion Within an immunocompromised patient population, differences in organism identification between three commercially available RDT panels did not impact theoretical antibiotic prescribing. Disclosures J. Kristie Johnson, PhD, D(ABMM), GenMark (Speaker’s Bureau) Kimberly C. Claeys, PharmD, GenMark (Speaker’s Bureau)

1022. Evaluating the Impact of GenMark Dx ePlex® Blood Culture Identification (BCID) on Gram-negative Bloodstream Infections

Background The GenMark Dx ePlex BCID Gram-Negative (GN) panel utilizes electrowetting technology to detect the most common causes of GN bacteremia (21 targets) and 6 antimicrobial resistance (AMR) genes from positive blood culture (BC) bottles. Rapid detection of extended spectrum β-lactamases (ESBL: CTX-M & carbapenemases: KPC, NDM, IMP, VIM, OXA 23/48), and highly resistant bacteria such as S. maltophilia should enable early optimization of antimicrobial therapy. Methods In this prospective study, aliquots of positive BC bottles with GN bacteria detected on Gram stain (GS) (n=108) received standard of care (SOC) culture and antimicrobial susceptibility testing (AST). Additionally, samples were evaluated with the BCID-GN panel but only SOC results were reported in the EMR and available to inform clinical decisions. Chart reviews were performed to evaluate the impact of the BCID-GN panel on the time to organism identification, AST results, and optimization of antimicrobial therapy. Results A total of 108 patients are included in the analysis (Table 1). Escherichia coli was the most common bacteria identified followed by Klebsiella pneumoniae, Pseudomonas aeruginosa, and Enterobacter species (Table 2). There were 11 (10.2%) polymicrobial bacteremias. Repeat BCs were obtained in 68 (63%) patients of which 13 (19%) were persistently positive. Eight (7%) patients had evidence of additional gram-positive (GP) pathogens. Organism identification occurred 26.7 hours faster than culture. In conjunction with GS, negative pan-GP marker data could have helped providers make the decision to remove GP antibiotic coverage in 63 (58%) patients. Narrowing from empiric meropenem could have occurred in 5 patients. Of 10 individuals infected with resistant isolates (1 S. maltophilia, 1 OXA 23/48, and 8 CTX-M) empiric therapy was ineffective in 4 (40%) cases. Optimization of antimicrobial therapy for 9 (8.3%) patients could have occurred an average of 52.4 hours earlier than standard methods. Table 1. Patient demographics and co-morbidities. Table 2. Gram-negative bacteria frequency. Conclusion The BCID-GN panel enabled earlier time to optimal treatment of highly resistant bacteria as well as multiple opportunities for narrowing gram negative spectrum and a higher degree of certainty in cessation of broad-spectrum gram-positive antibiotics Disclosures Todd P. McCarty, MD, Cidara (Grant/Research Support)GenMark (Grant/Research Support, Other Financial or Material Support, Honoraria for Research Presentation)T2 Biosystems (Consultant) Sixto M. Leal, Jr., MD, PhD, Abnova (Grant/Research Support)AltImmune (Grant/Research Support)Amplyx Pharmaceuticals (Grant/Research Support)Astellas Pharmaceuticals (Grant/Research Support)CNINE Dx (Grant/Research Support)GenMark Diagnostics (Grant/Research Support, Other Financial or Material Support, Honoraria- Research Presentation)IHMA (Grant/Research Support)IMMY Dx (Grant/Research Support)JMI/Sentry (Grant/Research Support)mFluiDx Dx (Grant/Research Support)SpeeDx Dx (Grant/Research Support)Tetraphase Pharmaceuticals (Grant/Research Support)

1234. Can Susceptibility to One Carbapenem be Conferred to Another? Frequency of Discordance in Gram-negative Clinical Isolates

Background Carbapenem-Resistant Enterobacterales (CRE) and Carbapenem-Resistant Pseudomonas aeruginosa (CRPA) can exhibit resistance to one carbapenem while remaining susceptible to another. While case reports describing discrepant carbapenem susceptibilities are available, the authors are unaware of any literature reporting aggregate carbapenem susceptibility discrepancies at a hospital level. Methods Susceptibility data from April 1, 2017 - December 31, 2017 was extracted through an antibiogram report for a 706-bed hospital. Ertapenem, imipenem-cilastatin, and meropenem susceptibilities were captured and compared for common Enterobacterales and Pseudomonas aeruginosa. Organism identification was performed using Matrix Assisted Laser Desorption Ionization-Time of Flight (MALDI-TOF) mass spectrometry. Antibiotic susceptibility testing was performed using BD PhoenixTM. Carbapenem susceptibilities were interpreted using the most updated Clinical and Laboratory Standards Institute (CLSI) breakpoints at the time of assessment (2021). Carbapenem discordance was defined as an organism being susceptible to one carbapenem and non- susceptible (intermediate or resistant) to another. Approval was obtained from the institution’s Institutional Review Board. Results Meropenem proved to be the most active antimicrobial for all organisms (Figure 1). Carbapenem susceptibility discordance ranged from 0%-23.8% (Table 1). There was a significant difference in the incidence of discordance between Enterobacterales and Pseudomonas aeruginosa isolates (2.6% vs. 6.1%, p &lt; 0.001). Of the 20 Pseudomonas aeruginosa isolates with discordant carbapenem susceptibilities, 70% were meropenem susceptible/imipenem non-susceptible and 30% were imipenem susceptible/meropenem non-susceptible. The most common site for discordance was urine for both Enterobacterales and Pseudomonas aeruginosa. However, while there was a significant rate of discordance between sites for Pseudomonas isolates, this was not the case for Enterobacterales (Table 2). Figure 1: Carbapenem Susceptibility by Isolate Table 1: Frequency of Carbapenem Discordance Table 2: Frequency of Carbapenem Discordance by Site Conclusion Due to the wide range of susceptibility discordance, clinical implications can be drastic if an institution is relying on susceptibility of one carbapenem to confer susceptibility to another carbapenem. Disclosures All Authors: No reported disclosures

“Blood Culture Utilization in the Hospital Setting: A Call for Diagnostic Stewardship”.

There has been significant progress in detection of bloodstream pathogens in recent decades with the development of more sensitive automated blood culture detection systems and availability of rapid molecular tests for faster organism identification and detection of resistance genes. However, most blood cultures in clinical practice do not grow organisms, suggesting that suboptimal blood culture collection practices (e.g., suboptimal blood volume) or suboptimal selection of patients to culture (i.e., blood cultures ordered for patients with low likelihood of bacteremia) may be occurring. A national blood culture utilization benchmark does not exist, nor do specific guidelines on when blood cultures are appropriate or when blood cultures are of low value and waste resources. Studies evaluating the potential harm associated with excessive blood cultures have focused on blood culture contamination which has been associated with significant increases in healthcare costs and negative consequences for patients related to exposure to unnecessary antibiotics and additional testing. Optimizing blood culture performance is important to ensure bloodstream infections (BSIs) are diagnosed while minimizing adverse events from overuse.

Is That Minnow in Your Bait Bucket an Invasive Species? An Inquiry-Based Activity for Teaching Taxonomy in College-Level Courses

Despite the importance that taxonomy and species identification have in our current understanding of ecology, evolution, and conservation of organisms, it is a challenging topic to teach. One of the primary reasons for this challenge is the lack of student motivation to learn organism classification and identification, which is often reinforced by curricula that do not show the practical value of taxonomic knowledge. This article describes an inquiry-based learning activity designed to show students the real-world value of organism identification. In this activity, students relate the misidentification of baitfish to the spread of invasive species via the baitfish industry. Students role play as fish ecologists and help a bait shop owner identify the specimens in their baitfish supply and subsequently develop a strategy to ensure that the business is not contributing to the spread of invasive species. By relating the field of taxonomy to species invasions, instructors can show students that they are learning information and gaining skills that have utility outside of the classroom. We found this to be an appealing alternative to other species identification activities, which typically focus on low-level learning, and we are excited to share our approach with the readers of The American Biology Teacher.

Outcomes of Rapid Identification of Bacteremia in Combination with Antimicrobial Stewardship Intervention

Background: Rapid diagnostic tests designed to provide bacterial identification and detection of resistance genes directly from positive blood cultures can significantly reduce the time to definitive results, ensuring appropriate and timely antibiotic administration while simultaneously decreasing antibiotic overuse and development of antimicrobial resistance. However, their impact on in-hospital mortality and length of stay (LOS) is yet to be fully assessed. Methods: We retrospectively reviewed bacteremia cases in patients hospitalized over a 6-month period before (n = 78) and after (n = 93) the implementation of Verigene bacterial nanoparticle testing. Exclusion criteria included age >90 years, bacteremia thought to be a contaminant, polymicrobial bacteremia, or hospice admission. Verigene was performed at a central laboratory from 6 a.m. to 11 p.m. Pharmacists notified physicians of results and assisted with antibiotic modifications. Patient demographics, time to organism identification, time to effective antimicrobial therapy, and other key clinical parameters were compared. The primary outcomes were in-hospital LOS, 14-day mortality, and 30-day mortality. Secondary outcomes included time to effective antibiotic therapy and intensive care unit (ICU) LOS. Results: Organism identification was achieved more quickly (4.9 hours vs 44.5 hours; P < .001) and effective antibiotic therapy was started earlier after Verigene implementation. The mean in-hospital LOS decreased from 13.15 days to 10.02 days (P = .0071) after the Verigene intervention, despite a higher mean Charlson comorbidity index among the cases. Mortality was similar between groups. Conclusions: Rapid identification of gram-positive and gram-negative bacteremia with an antimicrobial stewardship intervention can decrease time to effective antibiotic therapy and total LOS.Funding: NoneDisclosures: None

809. Modified Laboratory Reporting to Prevent Catheter-Associated Urinary Tract Infections (CAUTIs)

Background Catheter-associated urinary tract infections (CAUTIs) are among the most common healthcare-associated infections. Many patients at our institution with a CAUTI do not have signs or symptoms of infection and bacterial growth likely represents asymptomatic bacteriuria (ASB). As a result, we implemented a Modified Lab Workflow (MLW) focused on diagnostic stewardship to improve urine culture (UCx) reporting and prevent misclassification and unnecessary treatment of CAUTIs. Methods On Sep. 1, 2019, laboratory reporting of Foley UCx was modified according to the protocol in Figure 1. UCx results were divided into 3 groups: (1) no growth, (2) mixed bacterial flora (≥3 organisms) not consistent with infection or (3) growth of ≤2 organisms with at least 1 organism ≥105 cfu/ml per National Healthcare Safety Network (NSHN) CAUTI definition. Group 3 UCx were resulted with instructions to the clinician (see Figure 1.). When requested, group 3 results were reviewed by Infection Prevention and released with organism identification and antibiotic susceptibility if it met Infectious Diseases Society of America (IDSA) CAUTI criteria. Otherwise they were resulted as: “Bacterial growth indicative of contamination or colonization.” Figure 1. Modified Laboratory Workflow for Reporting Urine Cultures from Foley Catheters Results Between Sep. 1, 2019 to Mar. 1, 2020, a total of 134 UCx from catheterized patients were reviewed. Forty-two (31%) of UCx were from patients with a Foley in-situ ≥48 hours and processed through MLW; 92 UCx were from a Foley in place &lt; 48 hours and excluded from the study. Of the 42 UCx processed via MLW, 16 (38%) were no growth and 7 (17%) had bacterial growth suggestive of contamination. For group 3, 19/42 (45%) had growth of significant bacteria but only 1(5%) met IDSA criteria for reporting. During the study, 6 additional CAUTIs were reported due to incorrect specimen labeling causing Foley urine specimens to subvert MLW. Conclusion During our study, we identified 1 CAUTI through apt MLW use. Seven total CAUTIs occurred (SIR=0.66); a majority due to incorrect UCx source labeling, resulting in missed MLW screening. Ten CAUTIs (SIR=0.97) were reported in the preceding 6 months. As part of a comprehensive CAUTI prevention program, a MLW can help reduce classification of ASB as a CAUTI. Education to providers on precise labeling of UCx source is a key component of a successful MLW. Disclosures All Authors: No reported disclosures