Detection of Extended-Spectrum β-Lactamases (ESBLs) and AmpC in Class A and Class B Carbapenemase-Producing
            <i>Enterobacterales</i>

Imkamp, Frank; Kolesnik-Goldmann, Natalia; Bodendoerfer, Elias; Zbinden, Reinhard; Mancini, Stefano

doi:10.1128/spectrum.02137-22

Cited by 5 publications

(2 citation statements)

References 23 publications

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“…This is considered a limitation of the method and may be a reason for the high AmpC prevalence in the above two studies. 6 , 20 …”

Section: Discussionmentioning

confidence: 99%

Evaluation of six commercial and in-house phenotypic tests for detection of AmpC β-lactamases: is routine detection possible?

Al Mamari,

Al Jabri,

Sami

et al. 2023

JAC-Antimicrobial Resistance

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Background Phenotypic characterization of the prevalent AmpC β-lactamases in clinical isolates is essential for making informed empirical decisions and critical for strengthening antimicrobial stewardship programmes. This study focused on assessing six assays, two in-house and four commercial phenotypic tests for detection of AmpC, to study the feasibility of making its detection a routine diagnostic microbiology laboratory activity. Methods A total of 116 non-duplicate Gram-negative bacteria that were resistant to third-generation cephalosporins and amoxicillin/clavulanic acid, and resistant or susceptible to piperacillin/tazobactam and carbapenems, were screened by cefoxitin discs for AmpC. These isolates were subjected to two in-house (AmpC Tris-EDTA and disc approximation) methods and four commercial tests: D69C AmpC Detection Set; D72C ESBL, AmpC & Carbapenemase Detection Set; combination disc test: ESBL + AmpC Screen Disc Kit; and AmpC MIC Test Strip for confirmation of AmpC production. Ten whole-genome-sequenced AmpC-confirmed Gram-negative isolates were used as positive controls and one as a negative control. Results The prevalence of AmpC β-lactamases was 16%. Escherichia coli was a major carrier of plasmid-mediated AmpC (26.5%), followed by Klebsiella pneumoniae (23.4%). Phenotypically, 61% of AmpCs were detected by Tris-EDTA (accuracy: 73.8%), 76% by disc approximation (accuracy: 89.2%), 75% by the D69C AmpC Detection Set (accuracy: 95.4%), 74% by the D72C AmpC, ESBL & Carbapenemase Detection Set (accuracy: 95.4%), 76% by the combination disc test (accuracy: 95.4%) and 63% by AmpC MIC Test Strip (accuracy: 87.7%). The sensitivity and specificity of D69C were 97.9% and 88.2%, respectively, and 95.9% and 93.8% for the combination disc test, while for the disc approximation test and D72C they were 93.9% and 75%, and 93.9% and 100%, respectively. Screening by cefoxitin screening was less sensitive (75%) and specific (25%). Disc approximation and the combination disc test detect AmpC in Enterobacterales and also Pseudomonas aeruginosa and Acinetobacter species. Conclusions We recommend the in-house disc approximation test and the commercial D69C, as well as the combination disc test, as excellent tools for detection of AmpC. The cefoxitin test overcalls AmpC and cannot be considered a good stand-alone test for AmpC detection.

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“…This is considered a limitation of the method and may be a reason for the high AmpC prevalence in the above two studies. 6 , 20 …”

Section: Discussionmentioning

confidence: 99%

Evaluation of six commercial and in-house phenotypic tests for detection of AmpC β-lactamases: is routine detection possible?

Al Mamari,

Al Jabri,

Sami

et al. 2023

JAC-Antimicrobial Resistance

View full text Add to dashboard Cite

show abstract

“…In Europe, the Antimicrobial Advice Ad Hoc Expert Group (AMEG) of the European Medicines Agency (EMA) has classified third-and fourth-generation cephalosporins as belonging to "Category B-Restrict" antibiotics, meaning their use in animals should be restricted and preferably be based on antimicrobial susceptibility testing to mitigate the risk to public health [2]. Resistance to ESCs has dramatically increased worldwide in this family of bacteria and is encoded predominantly by the extended-spectrum β-lactamase (ESBLs) and AmpC β-lactamase (AmpCs) genes [3,4]. The plasmid-mediated AmpC-like gene, bla CMY-2 , which reduces susceptibility to aztreonam, cephamycin, and third-generation cephalosporins, is one of the most prevalent among E. coli strains [5].…”

Section: Introductionmentioning

confidence: 99%

Comparison of IncK-blaCMY-2 Plasmids in Extended-Spectrum Cephalosporin-Resistant Escherichia coli Isolated from Poultry and Humans in Denmark, Finland, and Germany

Che,

Fresno,

Calvo-Fernandez

et al. 2024

Antibiotics

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Escherichia coli carrying IncK-blaCMY-2 plasmids mediating resistance to extended-spectrum cephalosporins (ESC) has been frequently described in food-producing animals and in humans. This study aimed to characterize IncK-blaCMY-2-positive ESC-resistant E. coli isolates from poultry production systems in Denmark, Finland, and Germany, as well as from Danish human blood infections, and further compare their plasmids. Whole-genome sequencing (Illumina) of all isolates (n = 46) confirmed the presence of the blaCMY-2 gene. Minimum inhibitory concentration (MIC) testing revealed a resistant phenotype to cefotaxime as well as resistance to ≥3 antibiotic classes. Conjugative transfer of the blaCMY-2 gene confirmed the resistance being on mobile plasmids. Pangenome analysis showed only one-third of the genes being in the core with the remainder being in the large accessory gene pool. Single nucleotide polymorphism (SNP) analysis on sequence type (ST) 429 and 1286 isolates showed between 0–60 and 13–90 SNP differences, respectively, indicating vertical transmission of closely related clones in the poultry production, including among Danish, Finnish, and German ST429 isolates. A comparison of 22 ST429 isolates from this study with 80 ST429 isolates in Enterobase revealed the widespread geographical occurrence of related isolates associated with poultry production. Long-read sequencing of a representative subset of isolates (n = 28) allowed further characterization and comparison of the IncK-blaCMY-2 plasmids with publicly available plasmid sequences. This analysis revealed the presence of highly similar plasmids in ESC-resistant E. coli from Denmark, Finland, and Germany pointing to the existence of common sources. Moreover, the analysis presented evidence of global plasmid transmission and evolution. Lastly, our results indicate that IncK-blaCMY-2 plasmids and their carriers had been circulating in the Danish production chain with an associated risk of spreading to humans, as exemplified by the similarity of the clinical ST429 isolate to poultry isolates. Its persistence may be driven by co-selection since most IncK-blaCMY-2 plasmids harbor resistance factors to drugs used in veterinary medicine.

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Investigating trends in antibiotic resistance of Escherichia coli isolated from clinical urine specimens in the Orkney Islands

Corse,

Cartwright

2024

Microbiology

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Urinary tract infections (UTIs) are extremely common, affecting people of all ages and health statuses. Although UTIs do not usually cause severe illness, in some cases they can lead to more serious complications, especially if their initial treatment is ineffective due to antimicrobial resistance (AMR). AMR is an increasing issue, exacerbated by misdiagnosis and inappropriate prescribing of antibiotics, thus facilitating further resistance. The aim of this study was to investigate the rates of AMR in Escherichia coli isolated from clinical urine specimens tested at the Balfour Hospital, Orkney, and determine trends related to patient risk factors. Antibiotic susceptibilities were tested for 100 isolates of uropathogenic E. coli using the VITEK 2 Compact (bioMérieux), and data were analysed using percentage resistance rates. Resistance rates were compared by patient sex, age and source (hospital versus community). The findings showed higher AMR in males compared with females, particularly for trimethoprim (TMP), with 52% in males and only 12% in females. AMR tended to be higher in E. coli isolated from hospital inpatients than from community specimens, except for amoxicillin (AMX) and co-amoxiclav. Finally, the study found that AMR of E. coli isolates was greater in patients aged over 50 than 18–50 years old, particularly for AMX and TMP. The highest resistance rates across all patient demographics were for AMX, implying that the use of this antibiotic for the treatment of E. coli UTIs is not appropriate.

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Detection of Extended-Spectrum β-Lactamases (ESBLs) and AmpC in Class A and Class B Carbapenemase-Producing Enterobacterales

Abstract: Antimicrobial resistance is a growing public health threat of broad concern worldwide. Timely detection of antibiotic resistance mechanisms can help to monitor and to curb the spread of resistant bacteria within the hospital setting as well as in the environment.

Cited by 5 publications

References 23 publications

Evaluation of six commercial and in-house phenotypic tests for detection of AmpC β-lactamases: is routine detection possible?

Evaluation of six commercial and in-house phenotypic tests for detection of AmpC β-lactamases: is routine detection possible?

Comparison of IncK-blaCMY-2 Plasmids in Extended-Spectrum Cephalosporin-Resistant Escherichia coli Isolated from Poultry and Humans in Denmark, Finland, and Germany

Investigating trends in antibiotic resistance of Escherichia coli isolated from clinical urine specimens in the Orkney Islands

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