Activity in vitro of 22 antimicrobial agents against clinical isolates of Listeria monocytogenes

Abstract Background OXA-48 is a carbapenemase with low-level hydrolytic activity toward cephalosporins. This study evaluated in vitro activities of ceftazidime-avibactam (CAZ-AVI), meropenem (MEM), meropenem-vaborbactam (MVB), ceftolozane-tazobactam (C/T), and other antimicrobial agents against 113 OXA-48-producing Enterobacterales with multiple resistance mechanisms collected in a 2017–2018 global surveillance program. Methods Nonduplicate clinical isolates of 113 Enterobacterales were collected from medical centers in 25 countries in 2017–2018. In vitro susceptibility tests were performed by broth microdilution with a custom-made panel consisting of CAZ-AVI, ceftazidime (CAZ), MEM, MVB, C/T, colistin (COL), gentamicin (GEN), levofloxacin (LEV), and amikacin (AMK). Whole genome sequencing or quantitative PCR data were used to analyze resistance mechanisms, such as OXA-48, extended-spectrum β-lactamase (ESBL), original-spectrum β-lactamase (OSBL), and AmpC β-lactamase. Clinical and Laboratory Standards Institute breakpoints were applied for susceptibility interpretations. Results Of 113 OXA-48–producing clinical isolates, 20 carried OXA-48 alone. The remaining 93 isolates carried additional β-lactamases, including 63 with ESBL (CTX-M-15) + OSBL (SHV, TEM), 15 with AmpC (DHA, AAC, CMY) + ESBL (CTX-M-15), and 15 with OSBL (SHV, TEM). 99.1% (all but 1) of all isolates tested were susceptible to CAZ-AVI, whereas 71.7%, 17.7%, and 14.2% were susceptible to MVB, MEM, and C/T, respectively. Among isolates harboring multiple resistance mechanisms (OXA-48 + ESBL + OSBL; n=63), 98.4%, 69.8%, 11.1%, and 7.9% were susceptible to CAZ-AVI, MVB, MEM, and C/T, respectively. Among isolates carrying OXA-48 + AmpC + ESBL + OSBL (n=15), 100%, 66.7%, 13.3%, and 13.3% were susceptible to CAZ-AVI, MVB, MEM, and C/T, respectively (Table). Aminoglycosides (AMK and GEN) and other β-lactams (eg, CAZ) were 20%–90% active against these isolates. COL was the second most effective comparator, inhibiting 83.2% of these isolates. Table Conclusion CAZ-AVI was the most effective agent in this study compared with other antibiotics, including β-lactams, β-lactam–β-lactamase inhibitor combinations, aminoglycosides, and COL, against OXA-48-producing Enterobacterales carrying multiple β-lactamases. Disclosures Lynn-Yao Lin, MS, AbbVie (Employee) Dmitri Debabov, PhD, AbbVie (Employee) William Chang, BS, AbbVie (Employee)

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In vitro susceptibility studies and detection of vancomycin resistance genes in clinical isolates of enterococci in Nagasaki, Japan

Epidemiology and Infection ◽

10.1017/s0950268897007954 ◽

1997 ◽

Vol 119 (2) ◽

pp. 175-181 ◽

Cited By ~ 8

Author(s):

Y. HIRAKATA ◽

T. YAMAGUCHI ◽

K. IZUMIKAWA ◽

J. MATSUDA ◽

K. TOMONO ◽

...

Keyword(s):

Resistance Genes ◽

Antimicrobial Agents ◽

The United States ◽

Vancomycin Resistance ◽

Single Step ◽

Clinical Isolates ◽

Glycopeptide Resistance ◽

In Vitro Susceptibility ◽

Enterococcus Gallinarum

Glycopeptide resistance in enterococci is now a cause of clinical concern in the United States and Europe. However, details of vancomycin resistance in enterococci in Japan have been unknown. We measured minimum inhibitory concentrations (MICs) of various antimicrobial agents for a total of 218 clinical strains of enterococci isolated in our hospital in 1995–6 in addition to 15 strains with known genotypic markers of resistance. We also screened vancomycin resistance genes using a single step multiplex-PCR.In clinical isolates, only two strains of Enterococcus gallinarum were of intermediate resistance to vancomycin (MIC, 8 μg/ml), while the others were all susceptible. Glycopeptides (vancomycin and teicoplanin) and streptogramins (RP 58500 and RPR 106972) showed potent antimicrobial effects for the isolates. In addition, ampicillin was also potent for Enterococcus faecalis, while ampicillin, minocycline and gentamicin were potent for Enterococcus avium. No vanA or vanB genes were detected, while vanC1 and vanC23 genes were detected from two and four strains, respectively. Our results suggest that incidence of VRE in Japan may be estimated as still very low at this time.

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In Vitro Activity of Eravacycline against Gram-Positive Bacteria Isolated in Clinical Laboratories Worldwide from 2013 to 2017

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01715-19 ◽

2019 ◽

Vol 64 (3) ◽

Cited By ~ 1

Author(s):

Ian Morrissey ◽

Stephen Hawser ◽

Sibylle H. Lob ◽

James A. Karlowsky ◽

Matteo Bassetti ◽

...

Keyword(s):

Antimicrobial Agents ◽

Clinical Isolates ◽

Gram Positive ◽

Content Type ◽

Gram Positive Bacteria ◽

Microdilution Method ◽

Clinical Laboratories ◽

Broth Microdilution Method ◽

Doubling Dilution

ABSTRACT Eravacycline is a novel, fully synthetic fluorocycline antibiotic being developed for the treatment of serious infections, including those caused by resistant Gram-positive pathogens. Here, we evaluated the in vitro activities of eravacycline and comparator antimicrobial agents against a recent global collection of frequently encountered clinical isolates of Gram-positive bacteria. The CLSI broth microdilution method was used to determine in vitro MIC data for isolates of Enterococcus spp. (n = 2,807), Staphylococcus spp. (n = 4,331), and Streptococcus spp. (n = 3,373) isolated primarily from respiratory, intra-abdominal, urinary, and skin specimens by clinical laboratories in 37 countries on three continents from 2013 to 2017. Susceptibilities were interpreted using both CLSI and EUCAST breakpoints. There were no substantive differences (a >1-doubling-dilution increase or decrease) in eravacycline MIC90 values for different species/organism groups over time or by region. Eravacycline showed MIC50 and MIC90 results of 0.06 and 0.12 μg/ml, respectively, when tested against Staphylococcus aureus, regardless of methicillin susceptibility. The MIC90 values of eravacycline for Staphylococcus epidermidis and Staphylococcus haemolyticus were equal (0.5 μg/ml). The eravacycline MIC90s for Enterococcus faecalis and Enterococcus faecium were 0.06 μg/ml and were within 1 doubling dilution regardless of the vancomycin susceptibility profile. Eravacycline exhibited MIC90 results of ≤0.06 μg/ml when tested against Streptococcus pneumoniae and beta-hemolytic and viridans group streptococcal isolates. In this surveillance study, eravacycline demonstrated potent in vitro activity against frequently isolated clinical isolates of Gram-positive bacteria (Enterococcus, Staphylococcus, and Streptococcus spp.), including isolates collected over a 5-year period (2013 to 2017), underscoring its potential benefit in the treatment of infections caused by common Gram-positive pathogens.

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Characterization of the pathogenesis and immune response to Listeria monocytogenes strains isolated from a sustained national outbreak

Scientific Reports ◽

10.1038/s41598-019-56028-3 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 1

Author(s):

Pallab Ghosh ◽

Yan Zhou ◽

Quentin Richardson ◽

Darren E. Higgins

Keyword(s):

Listeria Monocytogenes ◽

Laboratory Strain ◽

The United States ◽

Clinical Isolates ◽

T Cell Antigens ◽

Life Threatening ◽

Cellular Immune ◽

The Brain

AbstractListeria monocytogenes is an intracellular pathogen responsible for listeriosis, a foodborne disease that can lead to life-threatening meningitis. The 2011 L. monocytogenes cantaloupe outbreak was among the deadliest foodborne outbreaks in the United States. We conducted in vitro and in vivo infection analyses to determine whether strains LS741 and LS743, two clinical isolates from the cantaloupe outbreak, differ significantly from the common laboratory strain 10403S. We showed that LS741 and LS743 exhibited increased virulence, characterized by higher colonization of the brain and other organs in mice. Assessment of cellular immune responses to known CD8+ T cell antigens was comparable between all strains. However, pre-existing immunity to 10403S did not confer protection in the brain against challenge with LS741. These studies provide insights into the pathogenesis of clinical isolates linked to the 2011 cantaloupe outbreak and also indicate that currently utilized laboratory strains are imperfect models for studying L. monocytogenes pathogenesis.

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Comparative In Vitro Activities of Torezolid (DA-7157) against Clinical Isolates of Aerobic and Anaerobic Bacteria in South Korea

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00728-10 ◽

2010 ◽

Vol 54 (12) ◽

pp. 5381-5386 ◽

Cited By ~ 18

Author(s):

Jong Hwa Yum ◽

Sung Hak Choi ◽

Dongeun Yong ◽

Yunsop Chong ◽

Weon Bin Im ◽

...

Keyword(s):

South Korea ◽

Antimicrobial Agents ◽

Anaerobic Bacteria ◽

Clinical Isolates ◽

Bacterial Isolates ◽

First Line ◽

Gram Positive ◽

The World ◽

Aerobic And Anaerobic

ABSTRACT Resistance of Gram-positive pathogens to first-line antimicrobial agents has been increasing in many parts of the world. We compared the in vitro activities of torezolid with those of other antimicrobial agents, including linezolid, against clinical isolates of major aerobic and anaerobic bacteria. Torezolid had an MIC90 of ≤0.5 μg/ml for the Gram-positive bacterial isolates tested and was more potent than either linezolid or vancomycin.

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In VitroActivities of Retapamulin and 16 Other Antimicrobial Agents against Recently Obtained Streptococcus pyogenes Isolates

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01665-10 ◽

2011 ◽

Vol 55 (5) ◽

pp. 2406-2408 ◽

Cited By ~ 4

Author(s):

Emilio Pérez-Trallero ◽

Esther Tamayo ◽

Milagrosa Montes ◽

José M. García-Arenzana ◽

Victor Iriarte

Keyword(s):

Streptococcus Pyogenes ◽

Antimicrobial Agents ◽

Clinical Isolates ◽

Intrinsic Activity ◽

Antimicrobial Drugs ◽

Blood Samples ◽

Content Type ◽

Topical Antimicrobial

ABSTRACTRetapamulinin vitroactivity against 400Streptococcus pyogenesclinical isolates obtained from skin, pharynx, ear fluid, and blood samples recovered from 2007 to 2009 was studied. The isolates belonged to 26 differentemmtypes, including isolates nonsusceptible to erythromycin (n= 187), tetracycline (n= 99), ciprofloxacin (n= 59), and bacitracin (n= 43). Results were compared to the activities of 16 other antibiotics for topical and systemic use. Retapamulin MICs ranged from ≤0.015 to 0.12 μg/ml, showing the highest intrinsic activity among the topical antimicrobial drugs studied.

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