RESUMEN
The in vitro susceptibility testing interpretive criteria (STIC) for TZP against Enterobacterales were recently updated by the Food and Drug Administration (FDA), Clinical & Laboratory Standards Institute (CLSI), and European Committee on Antimicrobial Susceptibility Testing (EUCAST). The United States Committee on Antimicrobial Susceptibility Testing (USCAST) also recently reviewed TZP STIC for Enterobacterales and arrived at different STIC for Enterobacterales and herein we explain our recommendations and rationale behind them. Based on our review of the available data, USCAST does not recommend TZP STIC for certain Enterobacterales species that have a moderate to high likelihood of clinically significant AmpC production (E. cloacae, C. freundii, and K. aerogenes only) or for third-generation cephalosporin-non-susceptible (3GC-NS) Enterobacterales. USCAST recommends a TZP susceptibility breakpoint of ≤ 16/4 mg/L for third-generation cephalosporin-susceptible (3GC-S) Enterobacterales but only endorses the use of extended infusion TZP regimens for patients with infections due to these pathogens.
RESUMEN
We evaluated the activities of aztreonam/avibactam and recently approved ß-lactamase inhibitor combinations (BLICs) to compare the antimicrobial susceptibility patterns of Enterobacterales and Pseudomonas aeruginosa isolated from intensive care unit (ICU) and non-ICU patients. Clinical isolates (1/patient) were consecutively collected from 72 United States medical centres in 2020-2022 and susceptibility tested by broth microdilution. The results for 5421 isolates from ICU patients were analysed and compared to those for 20,649 isolates from non-ICU patients. Isolates from ventilator-associated pneumonia patients were analysed separately. Aztreonam/avibactam inhibited 100.0%/>99.9% Enterobacterales and 100.0%/98.3% of carbapenem-resistant Enterobacterales (CRE) from ICU/non-ICU patients at ≤8 mg/L, respectively. The CRE susceptibility rates were 88.5%/82.9% for ceftazidime/avibactam, 82.1%/81.2% for meropenem/vaborbactam, and 78.2%/72.6% for imipenem/relebactam among ICU/non-ICU isolates. Among the P. aeruginosa isolates from ICU/non-ICU patients, the susceptibility rates were 96.3%/97.6% for ceftazidime/avibactam, 97.2/98.4% for ceftolozane/tazobactam, 97.1%/98.0% for imipenem/relebactam, 77.8%/84.6% for piperacillin/tazobactam, and 76.9%/85.8% for meropenem; aztreonam/avibactam inhibited 78.0%/81.9% of P. aeruginosa at ≤8 mg/L. In summary, lower susceptibility rates were observed among ICU than non-ICU isolates. Aztreonam/avibactam exhibited potent in vitro activity and broad-spectrum activity against Enterobacterales from ICU and non-ICU patients, including CRE and isolates non-susceptible to newer BLICs. Against P. aeruginosa, aztreonam/avibactam showed a spectrum of activity comparable to that of piperacillin/tazobactam, meropenem, and ceftazidime.
RESUMEN
We subjected seven P. aeruginosa isolates to a 10-day serial passaging against five antipseudomonal agents to evaluate resistance levels post-exposure and putative resistance mechanisms in terminal mutants were analyzed by whole-genome sequencing analysis. Meropenem (mean, 38-fold increase), cefepime (14.4-fold), and piperacillin-tazobactam (52.9-fold) terminal mutants displayed high minimum inhibitory concentration (MIC) values compared to those obtained after exposure to ceftolozane-tazobactam (11.4-fold) and ceftazidime-avibactam (5.7-fold). Fewer isolates developed elevated MIC values for other ß-lactams and agents belonging to other classes when exposed to meropenem in comparison to other agents. Alterations in nalC and nalD, involved in the upregulation of the efflux pump system MexAB-OprM, were common and observed more frequently in isolates exposed to ceftazidime-avibactam and meropenem. These alterations, along with ones in mexR and amrR, provided resistance to most ß-lactams and levofloxacin but not imipenem. The second most common gene altered was mpl, which is involved in the recycling of the cell wall peptidoglycan. These alterations were mainly noted in isolates exposed to ceftolozane-tazobactam and piperacillin-tazobactam but also in one cefepime-exposed isolate. Alterations in other genes known to be involved in ß-lactam resistance (ftsI, oprD, phoP, pepA, and cplA) and multiple genes involved in lipopolysaccharide biosynthesis were also present. The data generated here suggest that there is a difference in the mechanisms selected for high-level resistance between newer ß-lactam/ß-lactamase inhibitor combinations and older agents. Nevertheless, the isolates exposed to all agents displayed elevated MIC values for other ß-lactams (except imipenem) and quinolones tested mainly due to alterations in the MexAB-OprM regulators that extrude these agents.
Asunto(s)
Antibacterianos , Compuestos de Azabiciclo , Ceftazidima , Meropenem , Pruebas de Sensibilidad Microbiana , Combinación Piperacilina y Tazobactam , Pseudomonas aeruginosa , Tazobactam , Inhibidores de beta-Lactamasas , beta-Lactamas , Antibacterianos/farmacología , Pseudomonas aeruginosa/efectos de los fármacos , Pseudomonas aeruginosa/genética , Inhibidores de beta-Lactamasas/farmacología , Compuestos de Azabiciclo/farmacología , Meropenem/farmacología , Tazobactam/farmacología , Ceftazidima/farmacología , beta-Lactamas/farmacología , Combinación Piperacilina y Tazobactam/farmacología , Combinación de Medicamentos , Cefalosporinas/farmacología , Cefepima/farmacología , Humanos , Piperacilina/farmacología , Secuenciación Completa del Genoma , Farmacorresistencia Bacteriana Múltiple/genéticaRESUMEN
BACKGROUND: Aztreonam-avibactam is under clinical development for treatment of infections caused by carbapenem-resistant Enterobacterales (CRE), especially those resistant to recently approved ß-lactamase inhibitor combinations (BLICs). OBJECTIVES: To evaluate a large collection of CRE isolates, including those non-susceptible to ceftazidime-avibactam, meropenem-vaborbactam, and/or imipenem-relebactam. METHODS: Overall, 24 580 Enterobacterales isolates were consecutively collected (1/patient) in 2020-2022 from 64 medical centres located in Western Europe (W-EU), Eastern Europe (E-EU), Latin America (LATAM), and the Asia-Pacific region (APAC). Of those, 1016 (4.1%) were CRE. Isolates were susceptibility tested by broth microdilution. CRE isolates were screened for carbapenemase genes by whole genome sequencing. RESULTS: Aztreonam-avibactam inhibited 99.6% of CREs at ≤8 mg/L. Ceftazidime-avibactam, meropenem-vaborbactam, and imipenem-relebactam were active against 64.6%, 57.4%, and 50.7% of CRE isolates, respectively; most of the non-susceptible isolates carried metallo-beta-lactamases. Aztreonam-avibactam was active against ≥98.9% of isolates non-susceptible to these BLICs. The activity of these BLICs varied by region, with highest susceptibility rates observed in W-EU (76.9% for ceftazidime-avibactam, 72.5% for meropenem-vaborbactam, 63.8% for imipenem-relebactam) and the lowest susceptibility rates identified in the APAC region (39.9% for ceftazidime-avibactam, 37.8% for meropenem-vaborbactam, and 27.5% for imipenem-relebactam). The most common carbapenemase types overall were KPC (44.6% of CREs), NDM (29.9%), and OXA-48-like (16.0%). KPC predominated in LATAM (64.1% of CREs in the region) and W-EU (61.1%). MBL occurrence was highest in APAC (59.5% of CREs in the region), followed by LATAM (34.0%), E-EU (28.9%), and W-EU (23.6%). CONCLUSIONS: Aztreonam-avibactam demonstrated potent activity against CRE isolates resistant to ceftazidime-avibactam, meropenem-vaborbactam, and/or imipenem-relebactam independent of the carbapenemase produced.
Asunto(s)
Aztreonam , Ácidos Borónicos , Inhibidores de beta-Lactamasas , Humanos , Aztreonam/farmacología , Meropenem , Inhibidores de beta-Lactamasas/farmacología , América Latina , Antibacterianos/farmacología , Ceftazidima/farmacología , Compuestos de Azabiciclo/farmacología , beta-Lactamasas/genética , Europa (Continente)/epidemiología , Combinación de Medicamentos , Imipenem/farmacología , Pruebas de Sensibilidad MicrobianaRESUMEN
OBJECTIVES: Lefamulin (Xenleta™), a pleuromutilin antibiotic, was approved for the oral and IV treatment of community-acquired bacterial pneumonia (CABP) in adults in 2019/2020. This study evaluated the in vitro activity of lefamulin and comparators against 19 584 unique bacterial isolates collected from patients with community-acquired respiratory tract infections and hospitalized patients with pneumonia within the global SENTRY Antimicrobial Surveillance Program during 2015-21. METHODS: Isolates were susceptibility tested by the CLSI broth microdilution method, and resistance mechanisms were investigated in isolates with elevated lefamulin MICs. RESULTS: Lefamulin exhibited potent antibacterial activity against the most common and typical CABP pathogens tested, including Streptococcus pneumoniae [MIC50/90, 0.06/0.25 mg/L; 99.9% susceptible (S)], Staphylococcus aureus (MIC50/90, 0.06/0.12 mg/L; 99.6% S), Haemophilus influenzae (MIC50/90, 0.5/2 mg/L; 99.1% S) and Moraxella catarrhalis (MIC50/90, 0.06/0.12 mg/L; 100.0% S). Potent activity was also observed against the less common pneumonia pathogens: ß-haemolytic (MIC50/90 of 0.03/0.06 mg/L) and viridans group Streptococcus spp. (MIC50/90 of 0.06/0.25 mg/L) and Haemophilus parainfluenzae (MIC50/90 of 1/4 mg/L). Lefamulin's activity was not adversely affected by resistance to macrolides, penicillin, tetracyclines, fluoroquinolones and other resistance phenotypes. Non-susceptibility/resistance to lefamulin was rare and primarily determined by ribosomal protection through vga(A) variants in S. aureus, overexpression of AcrAB-TolC efflux pump in H. influenzae or modifications in L3, L4 and 23SrRNA in Streptococcus spp. CONCLUSIONS: Based on the coverage of the most important CABP pathogens and lacking cross-resistance, lefamulin may represent a valuable empirical treatment option for ambulatory and hospitalized patients with CABP, particularly in settings with high prevalence of resistance.
Asunto(s)
Infecciones Comunitarias Adquiridas , Diterpenos , Neumonía , Compuestos Policíclicos , Infecciones del Sistema Respiratorio , Tioglicolatos , Humanos , Staphylococcus aureus , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Infecciones del Sistema Respiratorio/tratamiento farmacológico , Infecciones del Sistema Respiratorio/microbiología , Bacterias , Neumonía/tratamiento farmacológico , Pruebas de Sensibilidad Microbiana , Infecciones Comunitarias Adquiridas/tratamiento farmacológico , Infecciones Comunitarias Adquiridas/microbiología , Haemophilus influenzaeRESUMEN
Ceftibuten/ARX-1796 (avibactam prodrug) is a novel oral antibacterial combination in early clinical development for the treatment of complicated urinary tract infections (cUTI) including pyelonephritis. ARX-1796 is the novel avibactam prodrug being combined with ceftibuten for oral dosing that is converted to active avibactam in vivo. A Clinical and Laboratory Standards Institute (CLSI) M23 (2018) tier 2 broth microdilution quality control (QC) study was conducted with ceftibuten-avibactam to establish MIC QC ranges. Ceftibuten-avibactam broth microdilution QC ranges were approved for Escherichia coli ATCC 25922 (0.016/4 to 0.12/4 µg/mL), E. coli NCTC 13353 (0.03/4 to 0.12/4 µg/mL), Klebsiella pneumoniae ATCC 700603 (0.06/4 to 0.25/4 µg/mL), K. pneumoniae ATCC BAA-1705 (0.03/4 to 0.25/4 µg/mL), and K. pneumoniae ATCC BAA-2814 (0.12/4 to 0.5/4 µg/mL) by the CLSI Subcommittee on Antimicrobial Susceptibility Testing in January 2022. Approved ceftibuten-avibactam QC ranges will support future clinical development, device manufacturers, and routine patient care.
Asunto(s)
Profármacos , Inhibidores de beta-Lactamasas , Humanos , Ceftibuteno , Inhibidores de beta-Lactamasas/farmacología , Inhibidores de beta-Lactamasas/uso terapéutico , Lactamas , Escherichia coli , Pruebas de Sensibilidad Microbiana , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Klebsiella pneumoniae , Control de Calidad , beta-LactamasasRESUMEN
A total of 35,360 Enterobacterales isolates were consecutively collected from 75 US medical centers in 2018-2022. Among these isolates, 2612 (7.4%) were categorized as multidrug-resistant (MDR). Isolates were susceptibility tested by reference broth microdilution methods. Carbapenem-resistant Enterobacterales (CRE) were screened for carbapenemase (CPE) genes by whole genome sequencing. The highest MDR rates was observed among Klebsiella pneumoniae (12.2%), followed by Raoultella spp. (10.9%) and Providencia stuartii (9.8%). Ceftazidime-avibactam and meropenem-vaborbactam were very active and showed identical susceptibility rates against MDR isolates (97.9%). Imipenem-relebactam (93.5% susceptible [S]) exhibited slightly lower susceptibility rates due to its limited activity against Morganellaceae family. The most active ß-lactamase inhibitor combination (BLI) against CRE isolates (n = 310) was ceftazidime-avibactam (84.2%S), followed by meropenem-vaborbactam (81.9%S) and imipenem-relebactam (74.8%S). All 3 BLIs were very active against KPC producers and none were active against MBL producers. Ceftazidime-avibactam exhibited greater activity against OXA-48-type producers than meropenem-vaborbactam and imipenem-vaborbactam.
Asunto(s)
Antibacterianos , Ceftazidima , Estados Unidos , Humanos , Meropenem/farmacología , Antibacterianos/farmacología , Ceftazidima/farmacología , Compuestos de Azabiciclo/farmacología , Combinación de Medicamentos , Imipenem/farmacología , beta-Lactamasas/genética , Carbapenémicos , Pruebas de Sensibilidad MicrobianaRESUMEN
Background: The Clinical and Laboratory Standards Institute (CLSI) lowered the Enterobacterales-susceptible/-resistant breakpoints for amikacin in 2023 from ≤16/≥64â mg/L to ≤4/≥16â mg/L and the breakpoints for gentamicin and tobramycin from ≤4/≥16â mg/L to ≤2/≥8â mg/L. Because aminoglycosides are frequently used to treat infections caused by multidrug-resistant (MDR) and carbapenem-resistant Enterobacterales (CRE), we evaluated the impact of these changes on the susceptibility rates (%S) of Enterobacterales collected from US medical centers. Methods: A total of 9809 Enterobacterales isolates were consecutively collected (1/patient) from 37 US medical centers in 2017-2021 and susceptibility was tested by broth microdilution. Susceptibility rates were calculated using CLSI 2022, CLSI 2023, and US Food and Drug Administration 2022 criteria. Aminoglycoside-nonsusceptible isolates were screened for genes encoding aminoglycoside-modifying enzymes (AMEs) and 16S rRNA methyltransferases (16RMT). Results: The CLSI breakpoint changes mostly affected amikacin, especially against MDR (94.0%S to 71.0%S), extended-spectrum ß-lactamase (ESBL)-producing (96.9%S to 79.7%S), and CRE (75.2%S to 59.0%S) isolates. Plazomicin was active against 96.4% of isolates and retained potent activity against CRE (94.0%S), ESBL-producing (98.9%S), and MDR (94.8%S) isolates. Gentamicin and tobramycin showed limited activity against resistant subsets of Enterobacterales. The AME-encoding genes and 16RMT were observed in 801 (8.2%) and 11 (0.1%) isolates, respectively. Plazomicin was active against 97.3% of the AME producers. Conclusions: The spectrum of activity of amikacin against resistant subsets of Enterobacterales was drastically reduced when interpretative criteria based on pharmacokinetic/pharmacodynamic parameters that are currently used to establish breakpoints for other antimicrobials were applied. Plazomicin was markedly more active than amikacin, gentamicin, or tobramycin against antimicrobial-resistant Enterobacterales.
RESUMEN
Background: Aztreonam/avibactam is under development to treat infections caused by Gram-negative bacteria. We evaluated the in vitro activities of aztreonam/avibactam and comparators against a global collection of carbapenem-resistant Enterobacterales (CRE), including ceftazidime/avibactam-resistant isolates. Methods: Isolates were consecutively collected (24â924; 1/patient) from 69 medical centres in 36 countries during 2019-21. Isolates were susceptibility tested by CLSI broth microdilution. All CRE isolates (nâ=â1098; 4.4%) were in silico screened for carbapenemase (CPE) genes after genome sequencing. CRE susceptibility results were stratified by CPE, geography and resistance phenotype. Results: Aztreonam/avibactam inhibited 99.6% of CREs at ≤8â mg/L (MIC50/90, 0.25/0.5â mg/L), including 98.9% (345/349) of ceftazidime/avibactam-resistant isolates. Aztreonam/avibactam activity was consistent across geographical regions (98.9%-100.0% inhibited at ≤8â mg/L), but susceptibility to comparators varied markedly. Susceptibility (CLSI criteria) for ceftazidime/avibactam and meropenem/vaborbactam ranged from 80.2% and 77.5% in Western Europe to 39.5% and 40.3% in the Asia-Pacific region, respectively. Aztreonam/avibactam retained activity against isolates non-susceptible to colistin (99.7% inhibited at ≤8â mg/L) or tigecycline (98.6% inhibited at ≤8â mg/L). A CPE gene was identified in 972 CRE isolates (88.5%). The most common CPEs were KPC (43.1% of CREs), NDM (26.6%) and OXA-48-like (18.7%); 57 isolates (5.2%) had >1 CPE gene. Aztreonam/avibactam inhibited 99.9% of CPE producers at ≤8â mg/L, whereas ceftazidime/avibactam and meropenem/vaborbactam exhibited limited activity against isolates producing MBL and/or OXA-48-like enzymes. Conclusions: Aztreonam/avibactam activity was not adversely affected by clinically relevant CPEs. Our results support aztreonam/avibactam development to treat infections caused by CRE, including MBL producers.
RESUMEN
Background: The temporal and longitudinal trends of ß-lactamases and their associated susceptibility patterns were analyzed for Escherichia coli and Klebsiella pneumoniae isolates consecutively collected in 56â United States hospitals during 2016-2020. Methods: Isolates (n = 19 453) were susceptibility tested by reference broth microdilution methods. Isolates that displayed minimum inhibitory concentration (MIC) values ≥2â mg/L for at least 2 of the following compounds-ceftazidime, ceftriaxone, aztreonam, or cefepime-or resistance to the carbapenems were submitted to whole genome sequencing for identification of ß-lactamases. Longitudinal and temporal trends were determined by slope coefficient. New CTX-M and OXA-1 variants were characterized. Results: Extended-spectrum ß-lactamases (ESBLs) were detected among 88.0% of the isolates that displayed elevated cephalosporin/aztreonam MICs without carbapenem resistance. bla CTX-M-15 was detected among 55.5% of the ESBL producers. ESBL rates were stable over time, but significant increases were noted among bloodstream infection and K pneumoniae isolates, mainly driven by an increase in bla CTX-M. Carbapenem resistance and carbapenemase genes were noted among 166 and 145 isolates, respectively, including 137 bla KPC, 6 bla SME, 3 bla OXA-48-like, and 3 bla NDM. Ceftazidime-avibactam and carbapenems were very active (>99% susceptibility) against ESBL producers without carbapenem resistance. Ceftazidime-avibactam inhibited 97.0% of the carbapenem-resistant isolates. This agent and meropenem-vaborbactam inhibited 96.4% and 85.0% of the 2020 isolates, respectively. Conclusions: Overall, ESBL-producing isolates were stable, but an increase was noted for K pneumoniae isolates driven by CTX-M production. Carbapenem-resistant Enterobacterales rates decreased in the study period. The prevalence of metallo-ß-lactamases and OXA-48-like remains low. Continuous surveillance of ß-lactamase-producing isolates is prudent.
RESUMEN
Background: As the frequency of metallo-ß-lactamase (MBL)-producing Enterobacterales is increasing worldwide, effective antimicrobials to treat the infections caused by these organisms are urgently needed. Methods: The activity of aztreonam-avibactam and comparators were evaluated against 27 834 Enterobacterales isolates collected from 74 US medical centers in 2019-2021. Isolates were susceptibility tested by broth microdilution. An aztreonam-avibactam pharmacokinetic/pharmacodynamic breakpoint of ≤8â mg/L was applied for comparison. Antimicrobial susceptibility and the frequency of key resistance phenotypes were assessed then stratified by year and infection type. Carbapenem-resistant Enterobacterales (CRE) were screened for carbapenemase (CPE) genes by whole genome sequencing. Results: Aztreonam-avibactam inhibited >99.9% of Enterobacterales at ≤8â mg/L. Only 3 isolates (0.01%) had an aztreonam-avibactam minimum inhibitory concentration (MIC) >8â mg/L. The CRE rates were 0.8%, 0.9%, and 1.1% in 2019, 2020, and 2021, respectively; 99.6% (260 of 261) of CRE isolates were inhibited at an aztreonam-avibactam MIC of ≤8â mg/L. The CRE susceptibility to meropenem-vaborbactam decreased from 91.7% in 2019 to 83.1% in 2020 and 76.5% in 2021 (82.1% overall). The CRE, multidrug-resistant, and extensively drug-resistant phenotypes were markedly higher among isolates from pneumonia compared with other infections. The most common carbapenemase among CRE was Klebsiella pneumoniae carbapenemase (65.5% of CRE), followed by New Delhi metallo-ß-lactamase (11.1%), oxacillinase (OXA)-48-like (4.6%), Serratia marcescens enzyme (2.3%), and imipenemase (1.5%). Among non-CPE-producing CRE isolates (n = 44; 16.9% of CRE), 97.7% were inhibited at ≤8â mg/L aztreonam-avibactam and 85.4% were meropenem-vaborbactam susceptible. Conclusions: The frequencies of MBL and OXA-48-type producers increased markedly. Aztreonam-avibactam demonstrated potent and consistent activity against Enterobacterales across infection types and over time.
RESUMEN
We evaluated the in vitro activity of ceftibuten-avibactam against Enterobacterales causing urinary tract infection (UTI). A total of 3216 isolates (1/patient) were consecutively collected from patients with UTI in 72 hospitals from 25 countries in 2021 then susceptibility tested by CLSI broth microdilution. Ceftibuten-susceptible breakpoints currently published by EUCAST (≤ 1 mg/L) and CLSI (≤ 8 mg/L) were applied to ceftibuten-avibactam for comparison. The most active agents were ceftibuten-avibactam (98.4%/99.6% inhibited at ≤ 1/ ≤ 8 mg/L), ceftazidime-avibactam (99.6% susceptible [S]), amikacin (99.1%S), and meropenem (98.2%S). Ceftibuten-avibactam (MIC50/90, 0.03/0.06 mg/L) was fourfold more potent than ceftazidime-avibactam (MIC50/90, 0.12/0.25 mg/L) based on MIC50/90 values. The most active oral agents were ceftibuten (89.3%S; 79.5% inhibited at ≤ 1 mg/L), levofloxacin (75.4%S), and trimethoprim-sulfamethoxazole (TMP-SMX; 73.4%S). Ceftibuten-avibactam inhibited 97.6% of isolates with an extended-spectrum ß-lactamase phenotype, 92.1% of multidrug-resistant isolates, and 73.7% of carbapenem-resistant Enterobacterales (CRE) at ≤ 1 mg/L. The second most active oral agent against CRE was TMP-SMX (24.6%S). Ceftazidime-avibactam was active against 77.2% of CRE isolates. In conclusion, ceftibuten-avibactam was highly active against a large collection of contemporary Enterobacterales isolated from patients with UTI and exhibited a similar spectrum to ceftazidime-avibactam. Ceftibuten-avibactam may represent a valuable option for oral treatment of UTI caused by multidrug-resistant Enterobacterales.
Asunto(s)
Antibacterianos , Infecciones Urinarias , Humanos , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Ceftibuteno , Combinación Trimetoprim y Sulfametoxazol , Pseudomonas aeruginosa , Ceftazidima/farmacología , Ceftazidima/uso terapéutico , Infecciones Urinarias/tratamiento farmacológico , Infecciones Urinarias/microbiología , Combinación de Medicamentos , Pruebas de Sensibilidad Microbiana , beta-Lactamasas/genéticaRESUMEN
OBJECTIVES: To evaluate the in-vitro activity of ceftazidime-avibactam, ceftolozane-tazobactam, meropenem-vaborbactam, imipenem-relebactam and comparator agents against contemporary Pseudomonas aeruginosa isolates from US hospitals. METHODS: In total, 3184 isolates were collected consecutively from 71 US medical centres in 2020-2021, and susceptibility tested by reference broth microdilution. Clinical Laboratory Standard Institute breakpoints were applied. RESULTS: Ceftazidime-avibactam [97.0% susceptible (S)], ceftolozane-tazobactam (98.0%S), imipenem-relebactam (97.3%S) and tobramycin (96.4%S) were the most active agents against the aggregate P. aeruginosa isolate collection, and retained good activity against piperacillin-tazobactam-non-susceptible, meropenem-non-susceptible and multi-drug-resistant (MDR) isolates. All other antimicrobials tested showed limited activity against piperacillin-tazobactam-non-susceptible, meropenem-non-susceptible and MDR isolates. The most common infections were pneumonia (45.9%), skin and skin structure infections (19.0%), urinary tract infections (17.0%) and bloodstream infections (11.7%); ceftazidime-avibactam, ceftolozane-tazobactam and imipenem-relebactam showed consistent activity against isolates from these infection types. Susceptibility to piperacillin-tazobactam and meropenem was lower among isolates from pneumonia compared with other infection types. CONCLUSIONS: Ceftazidime-avibactam, ceftolozane-tazobactam and imipenem-relebactam were highly active, and exhibited similar coverage against a large contemporary collection of P. aeruginosa isolates from US hospitals. Cross-resistance among the newer ß-lactams/ß-lactam inhibitors (BL/BLIs) varied markedly; ≥72.1% of isolates resistant to one of the three newer BL/BLIs approved for P. aeruginosa treatment remained susceptible to at least one of the other two BL/BLIs, indicating that all three should be tested in the clinical laboratory. These three BL/BLIs represent valuable therapeutic options for P. aeruginosa infection.
Asunto(s)
Neumonía , Infecciones por Pseudomonas , Humanos , Inhibidores de beta-Lactamasas/farmacología , Inhibidores de beta-Lactamasas/uso terapéutico , Meropenem/farmacología , Meropenem/uso terapéutico , Pseudomonas aeruginosa , Lactamas , Cefalosporinas/farmacología , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Tazobactam/farmacología , Tazobactam/uso terapéutico , Ceftazidima/farmacología , Ceftazidima/uso terapéutico , Compuestos de Azabiciclo/farmacología , Compuestos de Azabiciclo/uso terapéutico , Combinación Piperacilina y Tazobactam/uso terapéutico , Combinación de Medicamentos , Imipenem/farmacología , Neumonía/tratamiento farmacológico , Hospitales , Pruebas de Sensibilidad Microbiana , Infecciones por Pseudomonas/tratamiento farmacológicoRESUMEN
Ceftaroline and comparators were tested against 9,268 Staphylococcus aureus isolates from 33 United States hospitals (2018-2020). Ceftaroline (MIC50/90, 0.25/1 mg/L) susceptibility ranged from 95.4% (pneumonia) to 98.5% (skin and skin structure) and was 97.2% overall. Ceftaroline retained potent and broad-spectrum activity against methicillin-resistant isolates, with a 93.4% overall susceptibility.
Asunto(s)
Staphylococcus aureus Resistente a Meticilina , Infecciones Estafilocócicas , Humanos , Estados Unidos , Staphylococcus aureus , Pruebas de Sensibilidad Microbiana , Antibacterianos/farmacología , Cefalosporinas/farmacología , Infecciones Estafilocócicas/epidemiología , Hospitales , CeftarolinaRESUMEN
Five Enterobacter cloacae isolates were subjected to 10-day serial passage in broth microdilution with cefepime, meropenem, or ceftazidime-avibactam to evaluate increases in minimum inhibitory concentration (MIC) and resistance mechanisms after exposure. Post-exposure isolates displaying >2-fold changes from the parent isolate were analysed alongside the parent isolate. Increases in MIC were 4- to 256-fold (median: 16-fold) after cefepime exposure, 16- to 128-fold (64-fold) after meropenem, and 2- to 32-fold (8-fold) after ceftazidime-avibactam. Post-exposure isolates had diverse mechanisms, identified using a combination of short and long whole-genome sequencing. All agents selected for AmpC alterations in one isolate set. OmpC and TetA/AcrR regulator alterations were noted in meropenem and ceftazidime-avibactam post-exposure isolates of the same set. Other mutations in AmpC were noted when isolates were exposed to cefepime or ceftazidime-avibactam. A premature stop codon in the cell division inhibitor protein, MioC was observed when one parent isolate was exposed to any of the agents, indicating a cell persistence mechanism. Mutations in less common transporter systems and protein synthesis components were also noted. All agents showed cross-resistance to other ß-lactams and resistance mechanisms were diverse, with some not usually associated with ß-lactam resistance in Enterobacterales. This initial evaluation indicates that cefepime and meropenem select for isolates with higher MIC values compared to ceftazidime-avibactam. Further studies evaluating these findings should be performed for other species for which the primary ß-lactam resistance mechanism is not gene acquisition. These studies should evaluate these observations in vivo to assess their translation into patient treatment policies.
Asunto(s)
Antibacterianos , Enterobacter cloacae , Humanos , Cefepima/farmacología , Meropenem/farmacología , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Enterobacter cloacae/genética , Enterobacter cloacae/metabolismo , beta-Lactamasas/genética , beta-Lactamasas/metabolismo , Ceftazidima/farmacología , Compuestos de Azabiciclo/farmacología , Combinación de Medicamentos , Pruebas de Sensibilidad MicrobianaRESUMEN
Objectives: To evaluate the prevalence of acquired ß-lactamase genes and susceptibility profiles of carbapenem-nonsusceptible Enterobacterales (CNSE) clinical isolates collected in US hospitals during a 5-year period. Methods: Isolates were susceptibility tested by reference broth microdilution methods. Results were interpreted using CLSI breakpoints. Isolates displaying nonsusceptible MICs for imipenem or meropenem were categorized as CNSE. CNSE isolates were screened for ß-lactamase-encoding genes using whole-genome sequencing. New genes were cloned, expressed in an Escherichia coli background and susceptibility tested. Results: A total of 450 (1.3%) isolates were CNSE. Klebsiella pneumoniae serine carbapenemase (KPC) production was the most common resistance mechanism among CNSE isolates: 281/450 (62.4%) carried bla KPC, including three new variants. OXA-48-like and metallo-ß-lactamase (MBL) encoding genes were detected among seven and 12 isolates, respectively. Among MBL genes, bla NDM-1 was the most common, but bla NDM-5, bla VIM-1 and bla IMP-27 were also identified. 169 (37.6% of the CNSE) isolates did not produce carbapenemases. Ceftazidime/avibactam was the most active agent (95.0% to 100.0% susceptible) against CNSE isolates from all carbapenemase groups except MBL-producing isolates. Ceftazidime/avibactam, meropenem/vaborbactam and imipenem/relebactam inhibited 100.0%, 97.6% and 92.3% of the non-carbapenemase CNSE isolates, respectively. Among the three new bla KPC variants, one conferred resistance to ceftazidime/avibactam and low meropenem MIC results while the other two had profiles similar to bla KPC-2 or bla KPC-3. Conclusions: A decline in carbapenemase production was noticed in US hospitals in the 5-year period analysed in this study. New ß-lactam/ß-lactamase inhibitor combinations tested had good activity against CNSE isolates.
RESUMEN
Objectives: The Surveillance of Tedizolid Activity and Resistance (STAR) programme monitored the tedizolid activity against Staphylococcus aureus, Enterococcus faecalis, Streptococcus pyogenes, Streptococcus agalactiae and Streptococcus anginosus group. We evaluated the antimicrobial susceptibility of 47â400 unique Gram-positive clinical isolates from the STAR programme collected from USA (21â243), Europe (17â674), Asia-Pacific (4954) and Latin America (3529) medical centres (2015-19). Methods: All isolates were tested for susceptibility by reference broth microdilution method. WGS and in silico analysis were performed on linezolid-non-susceptible (NS) isolates. Results: Tedizolid was active against ≥99.9% of S. aureus (100.0% of MSSA and >99.9% of MRSA), E. faecalis, S. pyogenes, S. agalactiae and S. anginosus group isolates, with MIC50 values ranging from 0.12 to 0.25â mg/L and MIC90 values of 0.25â mg/L. Linezolid, vancomycin and daptomycin were also active agents against these organisms. Tedizolid inhibited all VRE and 73.1% of linezolid-NS E. faecalis isolates. Ampicillin and daptomycin retained 100.0% activity against VRE and linezolid-NS E. faecalis isolates. Linezolid-NS E. faecalis isolates carried mostly the optrA gene. G2576T alterations in the 23S rRNA were observed in one linezolid-NS S. aureus isolate and one linezolid-NS E. faecalis isolate. Conclusions: No resistance trends were observed for tedizolid during the study period.
RESUMEN
We evaluated the activity of ceftaroline against clinical isolates of ceftriaxone-nonsusceptible Streptococcus pneumoniae from United States medical centers. Streptococcus pneumoniae isolates (n = 21,750) were consecutively collected from 201 medical centers in 2008-2020 and tested for susceptibility by broth microdilution method. Among these isolates, 1,419 (6.5%) were ceftriaxone-nonsusceptible (ceftriaxone minimum inhibitory concentration [MIC], ≥2 mg/L). Other resistant subgroups analyzed included multidrug-resistant (MDR; nonsusceptibility to ≥3 classes of agents; n = 4,454) and extensively drug-resistant (XDR; nonsusceptibility to ≥5 classes; n = 1,708) isolates. Ceftriaxone susceptibility increased from 89.0% (2008-2011) to 98.1% (2018-2020). Ceftaroline was active against 99.9% of ceftriaxone-nonsusceptible isolates (MIC50/90, 0.25/0.25 mg/L) and retained potent activity against MDR (n = 4,454; MIC50/90, 0.12/0.25 mg/L; >99.9% susceptible) and XDR (n = 1,708; MIC50/90, 0.25/0.25 mg/L; 100.0% susceptible) isolates. Only one isolate had a ceftaroline MIC ≥0.5 mg/L. In summary, ceftaroline demonstrated potent and consistent activity over time (2008-2020) against a large collection of S. pneumoniae from U.S. medical centers, including ceftriaxone-nonsusceptible, MDR, and XDR isolates.
Asunto(s)
Ceftriaxona , Streptococcus pneumoniae , Antibacterianos/farmacología , Ceftriaxona/farmacología , Cefalosporinas/farmacología , Estados Unidos , CeftarolinaRESUMEN
BACKGROUND: Zidebactam, a bicyclo-acyl hydrazide ß-lactam 'enhancer' antibiotic, in combination with cefepime (WCK 5222) is under clinical development for the treatment of resistant Gram-negative infections. OBJECTIVES: To evaluate the in vitro activity of cefepime/zidebactam and comparators against 24â220 Gram-negative bacteria. METHODS: Organisms were consecutively collected in 2018-19 from 137 medical centres located in the USA (nâ=â9140), Western Europe (W-EU; nâ=â5929), Eastern Europe (E-EU; nâ=â3036), the Asia-Pacific region (APAC; nâ=â3791) and Latin America (LATAM; nâ=â2324). The isolates were susceptibility tested using the broth microdilution method as part of the SENTRY Program. Cefepime/zidebactam was tested at a 1:1 ratio. RESULTS: Cefepime/zidebactam was highly active against Enterobacterales (MIC50/90 0.03/0.25â mg/L; 99.9% inhibited at ≤8â mg/L) and retained potent activity against carbapenem-resistant Enterobacterales (CRE) isolates (97.8% inhibited at ≤8â mg/L). CRE rates varied widely from 1.1% in the USA to 1.9% in W-EU, 3.6% in APAC and 14.6% in E-EU (3.9% overall). The most common carbapenemase genes observed overall were blaKPC (37.6% of CRE), blaOXA-48-like (30.0%) and blaNDM (23.8%). Resistance to ceftazidime/avibactam among CRE was elevated in APAC (64.8%), E-EU (25.5%) and LATAM (20.7%). Against Pseudomonas aeruginosa, cefepime/zidebactam inhibited 99.2% of isolates at ≤8â mg/L and susceptibility to ceftazidime/avibactam and ceftolozane/tazobactam was lowest in E-EU (83.9% and 82.0%, respectively). Cefepime/zidebactam exhibited good activity against Stenotrophomonas maltophilia (80.0% inhibited at ≤8â mg/L) and Burkholderia cepacia (89.4% inhibited at ≤8â mg/L). CONCLUSIONS: Cefepime/zidebactam demonstrated potent in vitro activity against a large worldwide collection of contemporary clinical isolates of Gram-negative bacteria.