Genotypic and phenotypic identification of Aeromonas species and CphA-mediated carbapenem resistance in Queensland, Australia

Holly A Sinclair; Claire Heney; Hanna E Sidjabat; Narelle M George; Haakon Bergh; Snehal N Anuj; Graeme R Nimmo; David L Paterson

doi:10.1016/j.diagmicrobio.2016.02.005

Genotypic and phenotypic identification of Aeromonas species and CphA-mediated carbapenem resistance in Queensland, Australia

Diagn Microbiol Infect Dis. 2016 May;85(1):98-101. doi: 10.1016/j.diagmicrobio.2016.02.005. Epub 2016 Mar 10.

Authors

Holly A Sinclair¹, Claire Heney², Hanna E Sidjabat³, Narelle M George², Haakon Bergh², Snehal N Anuj², Graeme R Nimmo⁴, David L Paterson⁵

Affiliations

¹ Pathology Queensland, Microbiology Department, Herston, QLD, Australia. Electronic address: holly.sinclair@health.qld.gov.au.
² Pathology Queensland, Microbiology Department, Herston, QLD, Australia.
³ University of Queensland Centre for Clinical Research, Herston, QLD, Australia.
⁴ Pathology Queensland, Microbiology Department, Herston, QLD, Australia; Griffith University, Southport, QLD, Australia.
⁵ Pathology Queensland, Microbiology Department, Herston, QLD, Australia; University of Queensland Centre for Clinical Research, Herston, QLD, Australia.

PMID: 26971634
DOI: 10.1016/j.diagmicrobio.2016.02.005

Abstract

Infection caused by Aeromonas spp. ranges from superficial wound infection to life-threatening septicemia. Carbapenem resistance due to metallo-beta-lactamase, CphA encoded by the cphA gene, is a significant problem. This study defines Aeromonas spp. causing clinical disease in Queensland, Australia. Phenotypic tests for carbapenemase detection were assessed. One hundred Aeromonas isolates from blood (22), wound (46), sterile sites (11), stool (18), eye (2), and sputum (1) were characterized by rpoB and gyrB sequencing. Meropenem susceptibility by VITEK2, disk diffusion, and E-test MIC were determined. Carbapenemase production was assessed by Carba NP test and cphA by PCR. Gene sequencing identified isolates as Aeromonas dhakensis (39), Aeromonas veronii (21), Aeromonas hydrophila (20), Aeromonas caviae (14), Aeromonas jandaei (4), Aeromonas bestiarum (1), and Aeromonas sanarellii (1). Disk diffusion and E-test failed to detect resistance in isolates with presence of cphA. Carba NP was performed with 97.4% sensitivity and 95.7% specificity. Carbapenem resistance gene cphA was detected in A. veronii (21; 100%), A. hydrophila (18; 90%), A. dhakensis (34; 87.2%), A. jandaei (3; 75%), and A. bestiarum (1; 100%) but not A. caviae. We found that A. dhakensis was the predominant species, a previously unrecognized pathogen in this region.

Keywords: Aeromonas; Carbapenem resistance; CphA.

MeSH terms

Aeromonas / classification
Aeromonas / drug effects*
Aeromonas / genetics*
Aeromonas / isolation & purification
Anti-Bacterial Agents / pharmacology*
Australia
Bacterial Typing Techniques
Carbapenems / pharmacology*
Genotype*
Gram-Negative Bacterial Infections / diagnosis
Gram-Negative Bacterial Infections / microbiology
Humans
Microbial Sensitivity Tests*
Sensitivity and Specificity
beta-Lactam Resistance*
beta-Lactamases / genetics*

Substances

Anti-Bacterial Agents
Carbapenems
beta-Lactamases