In vivo Evolution of CMY-2 to CMY-33 β-Lactamase in Escherichia coli ST131: Characterization of an Acquired Extended-Spectrum AmpC (ESAC) Conferring Resistance to Cefepime.

Pires, João; Taracila, Magdalena; Bethel, Christopher R; Doi, Yohei; Kasraian Fard, Sara; Tinguely, Regula; Sendi, Parham; Bonomo, Robert A; Endimiani, Andrea (2015). In vivo Evolution of CMY-2 to CMY-33 β-Lactamase in Escherichia coli ST131: Characterization of an Acquired Extended-Spectrum AmpC (ESAC) Conferring Resistance to Cefepime. Antimicrobial agents and chemotherapy, 59(12), pp. 7483-7488. American Society for Microbiology 10.1128/AAC.01804-15

[img] Text
AAC.01804-15.full.pdf - Published Version
Restricted to registered users only
Available under License Publisher holds Copyright.

Download (825kB) | Request a copy

Cefepime is frequently prescribed to treat infections caused by AmpC-producing Gram-negative bacteria. CMY-2 is the most common plasmid-mediated AmpC (pAmpC) β-lactamase. Unfortunately, CMY variants conferring enhanced cefepime resistance are reported. Here, we describe the evolution of CMY-2 to an extended-spectrum AmpC (ESAC) in clonally identical E. coli isolates obtained from a patient. The CMY-2-producing E. coli (CMY-2-Ec) was isolated from a wound. Thirty days later, one CMY-33-producing E. coli (CMY-33-Ec) was detected in bronchoalveolar lavage. Two weeks before the isolation of CMY-33-Ec, the patient received cefepime.CMY-33-Ec and CMY-2-Ec were identical by rep-PCR, being of hyperepidemic ST131, but showed different β-lactam MICs (e.g., cefepime 16 vs. ≤0.5 μg/ml). Identical CMY-2-Ec isolates were also found in a rectal swab. CMY-33 differs from CMY-2 by a Leu293-Ala294 deletion. Expressed in E. coli DH10B, both CMYs conferred resistance to ceftazidime (≥256 μg/ml), but cefepime MICs were higher for CMY-33 than CMY-2 (8 vs. 0.25 μg/ml). The kcat/Km or kinact/KI (μM(-1) s(-1)) indicated that CMY-33 possesses an ESBL-like spectrum compared to CMY-2 (cefoxitin: 0.2 vs. 0.4; ceftazidime: 0.2 vs. not measurable; cefepime: 0.2 vs. not measurable; tazobactam 0.0018 vs. 0.0009). Using molecular modeling, we show that a widened active site (∼4 Å shift) may play a significant role in enhancing cefepime hydrolysis. This is the first in vivo demonstration of a pAmpC that under cephalosporin treatment expands its substrate spectrum resembling an ESBL. The prevalence of CMY-2-Ec isolates is rapidly increasing worldwide, therefore awareness that cefepime treatment may select for resistant isolates is critical.

Item Type:

Journal Article (Original Article)

Division/Institute:

04 Faculty of Medicine > Service Sector > Institute for Infectious Diseases
04 Faculty of Medicine > Service Sector > Institute for Infectious Diseases > General Bacteriology
04 Faculty of Medicine > Department of Haematology, Oncology, Infectious Diseases, Laboratory Medicine and Hospital Pharmacy (DOLS) > Clinic of Infectiology

UniBE Contributor:

Kasraian Fard, Sara; Tinguely, Regula; Sendi, Parham and Endimiani, Andrea

Subjects:

500 Science > 570 Life sciences; biology
600 Technology > 610 Medicine & health

ISSN:

0066-4804

Publisher:

American Society for Microbiology

Language:

English

Submitter:

Annelies Luginbühl

Date Deposited:

01 Oct 2015 11:02

Last Modified:

26 Jun 2016 02:07

Publisher DOI:

10.1128/AAC.01804-15

PubMed ID:

26392491

BORIS DOI:

10.7892/boris.72017

URI:

https://boris.unibe.ch/id/eprint/72017

Actions (login required)

Edit item Edit item
Provide Feedback