Summary of Ceftaroline Activity against Pathogens in the United States, 2010: Report from the Assessing Worldwide Antimicrobial Resistance Evaluation (AWARE) Surveillance Program

ABSTRACTTheAssessingWorldwideAntimicrobialResistanceEvaluation (AWARE) surveillance program is a sentinel resistance monitoring system designed to track the activity of ceftaroline and comparator agents. In the United States, a total of 8,434 isolates were collected during the 2010 surveillance program from 65 medical centers distributed across the nine census regions (5 to 10 medical centers per region). All organisms were isolated from documented infections, including 3,055 (36.2%) bloodstream infections, 2,282 (27.1%) respiratory tract infections, 1,965 (23.3%) acute bacterial skin and skin structure infections, 665 (7.9%) urinary tract infections, and 467 (5.5%) miscellaneous other infection sites. Ceftaroline was the most potent β-lactam agent tested against staphylococci. The MIC90values were 1 μg/ml for methicillin-resistantStaphylococcus aureus(MRSA; 98.4% susceptible) and 0.5 μg/ml for methicillin-resistant coagulase-negative staphylococci (CoNS). Ceftaroline was 16- to 32-fold more potent than ceftriaxone against methicillin-susceptible staphylococcal strains. All staphylococcus isolates (S. aureusand CoNS) were inhibited at ceftaroline MIC values of ≤2 μg/ml. Ceftaroline also displayed potent activity against streptococci (MIC90, 0.015 μg/ml for beta-hemolytic streptococci; MIC90, 0.25 μg/ml for penicillin-resistantStreptococcus pneumoniae). Potent activity was also shown against Gram-negative pathogens (Haemophilus influenzae,Haemophilus parainfluenzae, andMoraxella catarrhalis). Furthermore, wild-type strains ofEnterobacteriaceae(non-extended-spectrum β-lactamase [ESBL]-producing strains and non-AmpC-hyperproducing strains) were often susceptible to ceftaroline. Continued monitoring through surveillance networks will allow for the assessment of the evolution of resistance as this new cephalosporin is used more broadly to provide clinicians with up-to-date information to assist in antibiotic stewardship and therapeutic decision making.

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Surveillance of Omadacycline Activity Tested against Clinical Isolates from the United States and Europe as Part of the 2016 SENTRY Antimicrobial Surveillance Program

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.02327-17 ◽

2018 ◽

Vol 62 (4) ◽

Cited By ~ 37

Author(s):

Michael A. Pfaller ◽

Michael D. Huband ◽

Dee Shortridge ◽

Robert K. Flamm

Keyword(s):

United States ◽

Moraxella Catarrhalis ◽

The United States ◽

Surveillance Program ◽

Bacterial Isolates ◽

Content Type ◽

Medical Centers ◽

Antimicrobial Surveillance ◽

Serious Infections ◽

Viridans Group Streptococci

ABSTRACTOmadacycline was tested against 21,000 bacterial isolates collected prospectively from medical centers in Europe and the United States during 2016. Omadacycline was active againstStaphylococcus aureus(MIC50/MIC90, 0.12/0.25 mg/liter), including methicillin-resistantS. aureus(MRSA); streptococci (MIC50/MIC90, 0.06/0.12 mg/liter), includingStreptococcus pneumoniae, viridans group streptococci, and beta-hemolytic streptococci;Enterobacteriaceae, includingEscherichia coli(MIC50/MIC90, 0.5/2 mg/liter);Haemophilus influenzae(MIC50/MIC90, 1/1 mg/liter); andMoraxella catarrhalis(MIC50/MIC90, 0.25/0.25 mg/liter). Omadacycline merits further study in serious infections where resistant pathogens may be encountered.

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Ceftobiprole Activity against Bacteria from Skin and Skin Structure Infections in the United States from 2016 through 2018

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.02566-19 ◽

2020 ◽

Vol 64 (6) ◽

Author(s):

Robert K. Flamm ◽

Leonard R. Duncan ◽

Kamal A. Hamed ◽

Jennifer I. Smart ◽

Rodrigo E. Mendes ◽

...

Keyword(s):

United States ◽

The United States ◽

Generation Cephalosporin ◽

Clinical Isolates ◽

Surveillance Program ◽

Coagulase Negative Staphylococci ◽

Gram Positive ◽

Content Type ◽

Skin Structure ◽

Highly Active

ABSTRACT Ceftobiprole medocaril is an advanced-generation cephalosporin prodrug that has qualified infectious disease product status granted by the US FDA and is currently being evaluated in phase 3 clinical trials in patients with acute bacterial skin and skin structure infections (ABSSSIs) and in patients with Staphylococcus aureus bacteremia. In this study, the activity of ceftobiprole and comparators was evaluated against more than 7,300 clinical isolates collected in the United States from 2016 through 2018 from patients with skin and skin structure infections. The major species/pathogen groups were S. aureus (53%), Enterobacterales (23%), Pseudomonas aeruginosa (7%), beta-hemolytic streptococci (6%), Enterococcus spp. (4%), and coagulase-negative staphylococci (2%). Ceftobiprole was highly active against S. aureus (MIC50/90, 0.5/1 mg/liter; 99.7% susceptible by EUCAST criteria; 42% methicillin-resistant S. aureus [MRSA]). Ceftobiprole also exhibited potent activity against other Gram-positive cocci. The overall susceptibility of Enterobacterales to ceftobiprole was 84.8% (>99.0% susceptible for isolate subsets that exhibited a non-extended-spectrum β-lactamase [ESBL] phenotype). A total of 74.4% of P. aeruginosa, 100% of beta-hemolytic streptococci and coagulase-negative staphylococci, and 99.6% of Enterococcus faecalis isolates were inhibited by ceftobiprole at ≤4 mg/liter. As expected, ceftobiprole was largely inactive against Enterobacterales that contained ESBL genes and Enterococcus faecium. Overall, ceftobiprole was highly active against most clinical isolates from the major Gram-positive and Gram-negative skin and skin structure pathogen groups collected at U.S. medical centers participating in the SENTRY Antimicrobial Surveillance Program during 2016 to 2018. The broad-spectrum activity of ceftobiprole, including potent activity against MRSA, supports its further evaluation for a potential ABSSSI indication.

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Activity of Ceftaroline and Epidemiologic Trends in Staphylococcus aureus Isolates Collected from 43 Medical Centers in the United States in 2009

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00315-11 ◽

2011 ◽

Vol 55 (9) ◽

pp. 4154-4160 ◽

Cited By ~ 51

Author(s):

Sandra S. Richter ◽

Kristopher P. Heilmann ◽

Cassie L. Dohrn ◽

Fathollah Riahi ◽

Andrew J. Costello ◽

...

Keyword(s):

United States ◽

Staphylococcus Aureus ◽

The United States ◽

Surveillance Program ◽

Content Type ◽

Type Iv ◽

Medical Centers ◽

High Level ◽

Resistance Rates

ABSTRACTAStaphylococcus aureussurveillance program was initiated in the United States to examine thein vitroactivity of ceftaroline and epidemiologic trends. Susceptibility testing by Clinical and Laboratory Standards Institute broth microdilution was performed on 4,210 clinically significant isolates collected in 2009 from 43 medical centers. All isolates were screened formecAby PCR and evaluated by pulsed-field gel electrophoresis. Methicillin-resistantS. aureus(MRSA) were analyzed for Panton-Valentine leukocidin (PVL) genes and the staphylococcal cassette chromosomemec(SCCmec) type. All isolates had ceftaroline MICs of ≤2 μg/ml with an MIC50of 0.5 and an MIC90of 1 μg/ml. The overall resistance rates, expressed as the percentages of isolates that were intermediate and resistant (or nonsusceptible), were as follows: ceftaroline, 1.0%; clindamycin, 30.2% (17.4% MIC ≥ 4 μg/ml; 12.8% inducible); daptomycin, 0.2%; erythromycin, 65.5%; levofloxacin, 39.9%; linezolid, 0.02%; oxacillin, 53.4%; tetracycline, 4.4%; tigecycline, 0%; trimethoprim-sulfamethoxazole, 1.6%; vancomycin, 0%; and high-level mupirocin, 2.2%. ThemecAPCR was positive for 53.4% of the isolates. The ceftaroline MIC90s were 0.25 μg/ml for methicillin-susceptibleS. aureusand 1 μg/ml for MRSA. Among the 2,247 MRSA isolates, 51% were USA300 (96.9% PVL positive, 99.7% SCCmectype IV) and 17% were USA100 (93.4% SCCmectype II). The resistance rates for the 1,137 USA300 MRSA isolates were as follows: erythromycin, 90.9%; levofloxacin, 49.1%; clindamycin, 7.6% (6.2% MIC ≥ 4 μg/ml; 1.4% inducible); tetracycline, 3.3%; trimethoprim-sulfamethoxazole, 0.8%; high-level mupirocin, 2.7%; daptomycin, 0.4%; and ceftaroline and linezolid, 0%. USA300 is the dominant clone causing MRSA infections in the United States. Ceftaroline demonstrated potentin vitroactivity against recentS. aureusclinical isolates, including MRSA, daptomycin-nonsusceptible, and linezolid-resistant strains.

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1353. In Vitro Activity of Lefamulin (LEF) Against Bacterial Pathogens Commonly Causing Community-Acquired Bacterial Pneumonia (CABP): 2016 SENTRY Data From the United States

Open Forum Infectious Diseases ◽

10.1093/ofid/ofy210.1184 ◽

2018 ◽

Vol 5 (suppl_1) ◽

pp. S414-S414 ◽

Cited By ~ 1

Author(s):

Susanne Paukner ◽

Robert K Flamm ◽

Steven P Gelone ◽

Helio S Sader

Keyword(s):

United States ◽

Ribosomal Subunit ◽

The United States ◽

Vitro Activity ◽

Surveillance Program ◽

Respiratory Pathogens ◽

In Vitro Activity ◽

Medical Centers ◽

Tract Infections

Abstract Background LEF, the first pleuromutilin antibiotic for IV and oral use in humans, is in Phase 3 clinical trials for the treatment of CABP in adults. In the first of these to be completed, LEF demonstrated noninferiority to moxifloxacin ± linezolid. LEF inhibits bacterial translation by binding the 50S ribosomal subunit at the A- and P-sites in the peptidyl transferase center. CABP is a leading cause of infectious diseases in the United States and increasing antibacterial resistance complicates its treatment. This study investigated the in vitro activity of LEF and comparators against a contemporary set of bacterial respiratory pathogens collected in the United States. Methods Isolates (n = 1674, 1/patient) were collected from 32 medical centers in the United States as part of the SENTRY Surveillance Program. LEF and comparators were tested by CLSI broth microdilution methods, and susceptibility was determined using the CLSI (2018) breakpoints. Results LEF was the most active compound against Streptococcus pneumoniae (MIC50/90 of 0.12/0.12 µg/mL), and its activity was not affected by resistance to other antibiotic classes. S. pneumoniae isolates were susceptible to levofloxacin (99.1%) and ceftriaxone (97.7%), whereas only 53.9%, 63.9%, and 80.4% of isolates were susceptible to macrolides, penicillin (oral), and tetracycline, respectively. LEF also showed potent activity against Staphylococcus aureus (MIC50/90 of 0.06/0.12 µg/mL), including methicillin-resistant (MRSA) isolates (MIC50/90 of 0.06/0.12 µg/mL, 87.1% resistant to erythromycin), Haemophilus influenzae, (MIC50/90 of 0.5/1 µg/mL, 26.9% β-lactamase producing), and Moraxella catarrhalis (MIC50/90 0.06/0.06 µg/mL, 96.5% β-lactamase positive) (figure). Conclusion LEF displayed potent in vitro activity against a contemporary collection of respiratory pathogens from the United States. LEF was active regardless of resistance phenotype to other antibiotic classes including β-lactams, tetracyclines, or macrolides. These results further support the clinical development of lefamulin for the treatment of CABP or other respiratory tract infections. Disclosures S. Paukner, Nabriva: Employee and Shareholder, Salary. R. K. Flamm, Nabriva: Research Contractor, Research grant. S. P. Gelone, Nabriva Therapeutics: Employee, Equity, Shareholder and Salary. Achaogen: Shareholder, Equity, Shareholder. H. S. Sader, Nabriva Therapeutics: Research Contractor, Research support.

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1273. Activity of Ceftolozane/Tazobactam and Comparators Against Enterobacterales and P. aeruginosa Isolates from Pediatric Patients—SMART United States 2017-2019

Open Forum Infectious Diseases ◽

10.1093/ofid/ofab466.1465 ◽

2021 ◽

Vol 8 (Supplement_1) ◽

pp. S725-S725

Author(s):

Sibylle Lob ◽

Meredith Hackel ◽

C Andrew DeRyke ◽

Kelly Harris ◽

Katherine Young ◽

...

Keyword(s):

United States ◽

Pediatric Patients ◽

Bloodstream Infections ◽

The United States ◽

Resistance Mechanisms ◽

Surveillance Program ◽

Independent Contractor ◽

Gram Negative ◽

Genes Encoding ◽

Tract Infections

Abstract Background Ceftolozane/tazobactam (C/T) is an antipseudomonal cephalosporin combined with a β-lactamase inhibitor approved by FDA and EMA for complicated urinary tract (cUTI) and complicated intraabdominal infections (cIAI), as well as hospital-acquired/ventilator-associated bacterial pneumonia (HABP/VABP) in patients ≥18 years. Clinical trials studying the use of C/T for pediatric patients with cUTI and cIAI are completed, and HABP/VABP pediatric studies are underway. We evaluated the antimicrobial activity of C/T against gram-negative isolates collected from patients ≤17 years in the United States (US) as part of the global SMART surveillance program. Methods In 2017-2019, 27 US clinical labs each collected up to 250 consecutive gram-negative pathogens per year. A total of 1336 isolates were collected from pediatric patients. MICs were determined using CLSI broth microdilution and breakpoints. C/T-nonsusceptible Enterobacterales (Ebact) and P. aeruginosa were screened for genes encoding β-lactamases. Results Among the 944 collected Ebact and 220 P. aeruginosa isolates, 40.7% and 76.4%, respectively, were collected from patients with respiratory tract infections, 37.0% and 10.0% from UTI, 13.7% and 8.2% from IAI, and 8.3% and 5.0% from bloodstream infections. The table shows antimicrobial susceptibility of Ebact, P. aeruginosa, and select phenotypes. C/T was active against 98% of Ebact, including 50 of 51 and 12 of 13 ESBL-non-CRE phenotype E. coli and K. pneumoniae, respectively. Among P. aeruginosa, C/T was active against 95% of isolates, 9-21 percentage points higher than the comparator β-lactams, and it maintained activity against 71-75% of P. aeruginosa isolates nonsusceptible to commonly used β-lactams. Among the 21 C/T-nonsusceptible Ebact, 2 isolates carried KPC and ESBL and 3 isolates carried only ESBL; in 16 isolates no β-lactamases were detected, of which 15 were species with intrinsic AmpC. Among 12 C/T-nonsusceptible P. aeruginosa, no acquired β-lactamases were detected, likely indicating chromosomally-mediated resistance mechanisms. Results Table Conclusion C/T could be a potential new treatment option for US pediatric patients with infections caused by Ebact and P. aeruginosa, including resistant phenotypes. Disclosures Sibylle Lob, PhD, IHMA (Employee)Pfizer, Inc. (Independent Contractor) Meredith Hackel, PhD MPH, IHMA (Employee)Pfizer, Inc. (Independent Contractor) C. Andrew DeRyke, PharmD, Merck & Co., Inc. (Employee, Shareholder) Kelly Harris, PharmD, BCPS, Merck & Co. Inc (Employee) Katherine Young, MS, Merck (Employee) Mary Motyl, PhD, Merck & Co., Inc. (Employee, Shareholder) Daniel F. Sahm, PhD, IHMA (Employee)Pfizer, Inc. (Independent Contractor)

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In Vitro Activity of Delafloxacin against Contemporary Bacterial Pathogens from the United States and Europe, 2014

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.02609-16 ◽

2017 ◽

Vol 61 (4) ◽

Cited By ~ 42

Author(s):

M. A. Pfaller ◽

H. S. Sader ◽

P. R. Rhomberg ◽

R. K. Flamm

Keyword(s):

United States ◽

Antimicrobial Agents ◽

Respiratory Infections ◽

The United States ◽

Content Type ◽

Medical Centers ◽

Tract Infections ◽

Viridans Group Streptococci ◽

Gram Positive Cocci

ABSTRACT The in vitro activities of delafloxacin and comparator antimicrobial agents against 6,485 bacterial isolates collected from medical centers in Europe and the United States in 2014 were tested. Delafloxacin was the most potent agent tested against methicillin-susceptible Staphylococcus aureus (MSSA), methicillin-resistant S. aureus, Streptococcus pneumoniae, viridans group streptococci, and beta-hemolytic streptococci and had activity similar to that of ciprofloxacin and levofloxacin against certain members of the Enterobacteriaceae. Overall, the broadest coverage of the tested pathogens (Gram-positive cocci and Gram-negative bacilli) was observed with meropenem and tigecycline in both Europe and the United States. Delafloxacin was shown to be active against organisms that may be encountered in acute bacterial skin and skin structure infections, respiratory infections, and urinary tract infections.

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Surveillance of Omadacycline Activity Tested against Clinical Isolates from the United States and Europe: Report from the SENTRY Antimicrobial Surveillance Program, 2016 to 2018

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.02488-19 ◽

2020 ◽

Vol 64 (5) ◽

Cited By ~ 1

Author(s):

Michael A. Pfaller ◽

Michael D. Huband ◽

Dee Shortridge ◽

Robert K. Flamm

Keyword(s):

United States ◽

Bacterial Infections ◽

Klebsiella Oxytoca ◽

The United States ◽

Community Acquired Pneumonia ◽

Surveillance Program ◽

Gram Positive ◽

Content Type ◽

Medical Centers ◽

Antimicrobial Susceptibility Tests

ABSTRACT Omadacycline is a broad-spectrum aminomethylcycline approved in October 2018 by the U.S. Food and Drug Administration for treating acute bacterial skin and skin structure infections and community-acquired pneumonia as both an oral and intravenous once-daily formulation. In this report, the activities of omadacycline and comparators were tested against 49,000 nonduplicate bacterial isolates collected prospectively during 2016 to 2018 from medical centers in Europe (24,500 isolates, 40 medical centers [19 countries]) and the United States (24,500 isolates, 33 medical centers [23 states and all 9 U.S. census divisions]). Omadacycline was tested by broth microdilution following the methods in Clinical and Laboratory Standards Institute document M07 (Methods for Dilution Antimicrobial Susceptibility Tests for Bacteria That Grow Aerobically; Approved Standard, 11th ed., 2018). Omadacycline (MIC50/90, 0.12/0.25 mg/liter) inhibited 98.6% of Staphylococcus aureus isolates at ≤0.5 mg/liter, including 96.3% of methicillin-resistant S. aureus isolates and 99.8% of methicillin-susceptible S. aureus isolates. Omadacycline potency was comparable for Streptococcus pneumoniae (MIC50/90, 0.06/0.12 mg/liter), viridans group streptococci (MIC50/90, 0.06/0.12 mg/liter), and beta-hemolytic streptococci (MIC50/90, 0.12/0.25 mg/liter), regardless of species and susceptibility to penicillin, macrolides, or tetracycline. Omadacycline was active against all Enterobacterales tested (MIC50/90, 1/8 mg/liter; 87.5% of isolates were inhibited at ≤4 mg/liter) except Proteus mirabilis (MIC50/90, 16/>32 mg/liter) and indole-positive Proteus spp. (MIC50/90, 8/32 mg/liter) and was most active against Escherichia coli (MIC50/90, 0.5/2 mg/liter), Klebsiella oxytoca (MIC50/90, 1/2 mg/liter), and Citrobacter spp. (MIC50/90, 1/4 mg/liter). Omadacycline inhibited 92.4% of Enterobacter cloacae species complex and 88.5% of Klebsiella pneumoniae isolates at ≤4 mg/liter. Omadacycline was active against Haemophilus influenzae (MIC50/90, 0.5/1 mg/liter), regardless of β-lactamase status, and against Moraxella catarrhalis (MIC50/90, ≤0.12/0.25 mg/liter). The potent activity of omadacycline against Gram-positive and -negative bacteria indicates that omadacycline merits further study in serious infections in which multidrug resistance and mixed Gram-positive and Gram-negative bacterial infections may be a concern.

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Bloodstream Infections Due to Candida Species: SENTRY Antimicrobial Surveillance Program in North America and Latin America, 1997-1998

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.44.3.747-751.2000 ◽

2000 ◽

Vol 44 (3) ◽

pp. 747-751 ◽

Cited By ~ 235

Author(s):

M. A. Pfaller ◽

R. N. Jones ◽

G. V. Doern ◽

H. S. Sader ◽

S. A. Messer ◽

...

Keyword(s):

United States ◽

Latin America ◽

Bloodstream Infections ◽

The United States ◽

Common Species ◽

Surveillance Program ◽

International Program ◽

The Third ◽

Medical Centers ◽

Antimicrobial Surveillance

ABSTRACT An international program of surveillance of bloodstream infections (BSI) in the United States, Canada, and Latin America detected 306 episodes of candidemia in 34 medical centers (22 in the United States, 6 in Canada, and 6 in Latin America) in 1997 and 328 episodes in 34 medical centers (22 in the United States, 5 in Canada, and 7 in Latin America) in 1998. Of the 634 BSI, 54.3% were due to Candida albicans, 16.4% were due to C. glabrata, 14.9% were due to C. parapsilosis, 8.2% were due to C. tropicalis, 1.6% were due to C. krusei, and 4.6% were due to other Candida spp. The percentage of BSI due to C. albicans decreased very slightly in the United States between 1997 and 1998 (56.2 to 54.4%;P = 0.68) and increased in both Canada (52.6 to 70.1%; P = 0.05) and Latin America (40.5 to 44.6%;P = 0.67). C. glabrata was the second most common species observed overall, and the percentage of BSI due toC. glabrata increased in all three geographic areas between 1997 and 1998. C. parapsilosis was the third most prevalent BSI isolate in both Canada and Latin America, accounting for 7.0 and 18.5% of BSI, respectively. Resistance to fluconazole (MIC, ≥64 μg/ml) and itraconazole (MIC, ≥1.0 μg/ml) was observed infrequently in both 1997 (2.3 and 8.5%, respectively) and 1998 (1.5 and 7.6%, respectively). Among the different species ofCandida, resistance to fluconazole and itraconazole was observed in C. glabrata and C. krusei, whereas isolates of C. albicans, C. parapsilosis, and C. tropicalis were all highly susceptible to both fluconazole (98.9 to 100% susceptible) and itraconazole (96.4 to 100% susceptible). Isolates from Canada and Latin America were generally more susceptible to both triazoles than U.S. isolates were. Continued surveillance appears necessary to detect these important changes.

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Bacterial Pathogens Isolated from Patients with Bloodstream Infection: Frequencies of Occurrence and Antimicrobial Susceptibility Patterns from the SENTRY Antimicrobial Surveillance Program (United States and Canada, 1997)

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.42.7.1762 ◽

1998 ◽

Vol 42 (7) ◽

pp. 1762-1770 ◽

Cited By ~ 284

Author(s):

Michael A. Pfaller ◽

Ronald N. Jones ◽

Gary V. Doern ◽

Kari Kugler ◽

The Sentry Participants Group

Keyword(s):

United States ◽

Antimicrobial Resistance ◽

Bloodstream Infections ◽

The United States ◽

Microbial Pathogens ◽

Surveillance Program ◽

Coagulase Negative Staphylococci ◽

Antimicrobial Resistance Genes ◽

Resistance Patterns ◽

Ongoing Surveillance

ABSTRACT The SENTRY Program was established in January 1997 to measure the predominant pathogens and antimicrobial resistance patterns of nosocomial and community-acquired infections over a broad network of sentinel hospitals in the United States (30 sites), Canada (8 sites), South America (10 sites), and Europe (24 sites). During the first 6-month study period (January to June 1997), a total of 5,058 bloodstream infections (BSI) were reported by North American SENTRY participants (4,119 from the United States and 939 from Canada). In both the United States and Canada, Staphylococcus aureus and Escherichia coli were the most common BSI isolates, followed by coagulase-negative staphylococci and enterococci.Klebsiella spp., Enterobacter spp.,Pseudomonas aeruginosa, Streptococcus pneumoniae, and β-hemolytic streptococci were also among the 10 most frequently reported species in both the United States and Canada. Although the rank orders of pathogens in the United States and Canada were similar, distinct differences were noted in the antimicrobial susceptibilities of several pathogens. Overall, U.S. isolates were considerably more resistant than those from Canada. The differences in the proportions of oxacillin-resistant S. aureus isolates (26.2 versus 2.7% for U.S. and Canadian isolates, respectively), vancomycin-resistant enterococcal isolates (17.7 versus 0% for U.S. and Canadian isolates, respectively), and ceftazidime-resistant Enterobacter sp. isolates (30.6 versus 6.2% for U.S. and Canadian isolates, respectively) dramatically emphasize the relative lack of specific antimicrobial resistance genes (mecA, vanA, and vanB) in the Canadian microbial population. Among U.S. isolates, resistance to oxacillin among staphylococci, to vancomycin among enterococci, to penicillin among pneumococci, and to ceftazidime amongEnterobacter spp. was observed in both nosocomial and community-acquired pathogens, although in almost every instance the proportion of resistant strains was higher among nosocomial isolates. Antimicrobial resistance continues to increase, and ongoing surveillance of microbial pathogens and resistance profiles is essential on national and international scales.

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1004. Frequency of Occurrence and Antimicrobial Susceptibility of Bacteria Isolated From Patients Hospitalized With Bloodstream Infections in United States Medical Centers (2015–2017)

Open Forum Infectious Diseases ◽

10.1093/ofid/ofy210.841 ◽

2018 ◽

Vol 5 (suppl_1) ◽

pp. S299-S299

Author(s):

Helio S Sader ◽

Robert K Flamm ◽

Michael A Pfaller ◽

Mariana Castanheira

Keyword(s):

United States ◽

Antimicrobial Susceptibility ◽

Bloodstream Infections ◽

The United States ◽

Research Support ◽

Coagulase Negative Staphylococci ◽

E Coli ◽

Medical Centers ◽

Carbapenem Resistant ◽

Carbapenem Resistant Enterobacteriaceae

Abstract Background Bloodstream infections (BSIs) cause significant morbidity and mortality. We evaluated the frequency and antimicrobial susceptibility of bacteria causing BSIs in the United States. Methods A total of 9,210 bacterial isolates were consecutively collected (1/patient) from 33 US medical centers in 2015–2017 and tested for susceptibility by reference broth microdilution methods in a central laboratory (JMI Laboratories) as part of the International Network for Optimal Resistance Monitoring (INFORM) program. Whole-genome sequencing was performed on carbapenem-resistant Enterobacteriaceae (CRE). Results The most common organisms were S. aureus (SA; 24.3%), E. coli (EC; 20.8%), K. pneumoniae (KPN; 9.1%), coagulase-negative staphylococci (7.3%), E. faecalis (5.5%), P. aeruginosa (PSA; 4.7%), and β-hemolytic streptococci (4.7%). Overall, 50.0% of isolates were Gram-negative bacilli (GNB) and 41.4% were Enterobacteriaceae (ENT). All SA were susceptible (S) to dalbavancin (MIC90, 0.03 μg/mL), linezolid, tigecycline (TGC), and vancomycin; >99.9% S to daptomycin, 97.6% S to ceftaroline, and 57.8% S to oxacillin. The most active agents against ENT were CAZ-AVI (99.9% S; table), amikacin (AMK; 99.7% S), and the carbapenems meropenem (MEM) and doripenem (99.1% S). Ceftolozane-tazobactam (C-T; tested in 2017 only) was active against 96.9% of ENT. Ceftriaxone (CRO)-S rates were 83.0% and 86.5% among EC and KPN, respectively. CRO-non-S KPN exhibited low S rates to most agents, except CAZ-AVI (99.1% S), TGC (93.6%), AMK (93.8%), and colistin (COL; 93.4%). Among 28 CRE isolates (0.7% of ENT), 21 produced a KPC-like, 2 an NMD-like, and 1 a KPC-17 and an NDM-1. COL (100.0% S), C-T (98.7%S), CAZ-AVI (98.2% S), AMK (97.9% S), and tobramycin (95.6% S) were very active against PSA. CAZ-AVI and C-T remained active against most PSA isolates non-S to MEM (93.0 and 95.0% S, respectively) and/or piperacillin–tazobactam (P-T; 88.9 and 91.3% S) and/or CAZ (86.9 and 88.2% S). Conclusion GNB represented 50.0% of bacteria isolated from patients with BSIs and the most active agents against these organisms were CAZ-AVI and AMK. Various agents exhibited excellent overall coverage against Gram-positives, including dalbavancin, daptomycin, linezolid, and TGC. Disclosures H. S. Sader, Allergan: Research Contractor, Research support. R. K. Flamm, Allergan: Research Contractor, Research support. M. A. Pfaller, Allergan: Research Contractor, Research support. M. Castanheira, Allergan: Research Contractor, Research support.

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