RT Journal Article SR Electronic(1) A1 Wu, Chi-Jung A1 Chen, Po-Lin A1 Wu, Jiunn-Jong A1 Yan, Jing-Jou A1 Lee, Chin-Chi A1 Lee, Hsin-Chun A1 Lee, Nan-Yao A1 Chang, Chia-Ming A1 Lin, Yu-Tzu A1 Chiu, Yen-Cheng A1 Ko, Wen-ChienYR 2012 T1 Distribution and phenotypic and genotypic detection of a metallo-β-lactamase, CphA, among bacteraemic Aeromonas isolates JF Journal of Medical Microbiology, VO 61 IS 5 SP 712 OP 719 DO https://doi.org/10.1099/jmm.0.038323-0 PB Microbiology Society, SN 1473-5644, AB The objectives of the study were to investigate the distribution of cphA-related genes (cphA) encoding a CphA metallo-β-lactamase (MBL) among 51 consecutive Aeromonas blood isolates and to compare different phenotypic methods for detecting CphA. The presence of cphA was detected by PCR. Four phenotypic methods, the imipenem-EDTA combined disc test, imipenem-EDTA MBL Etest, agar dilution test and modified Hodge test (MHT), were used to detect imipenem susceptibility and MBL production. The results showed that 35 (69 %) blood isolates had cphA. All (100 %) of 16 Aeromonas aquariorum isolates and 12 Aeromonas veronii isolates, and 4 (80 %) of 5 Aeromonas hydrophila isolates, carried cphA, but none of 15 Aeromonas caviae isolates did. With the standard inocula, irrespective of the presence or absence of cphA, all but one (50, 98 %) isolates were susceptible to imipenem tested by disc diffusion, Etest and agar dilution (104 c.f.u. spot inocula), and did not exhibit MBL production by the imipenem-EDTA combined disc test and MBL Etest. By the agar dilution test using large inocula (107 c.f.u.), 34 (97 %) of 35 cphA+ isolates had imipenem MICs of ≥16 µg ml−1, higher than the susceptible breakpoint (4 µg ml−1), and demonstrated positive results for the MHT, while one cphA+ and all 17 cphA− isolates had imipenem MICs of ≤4 µg ml−1. In conclusion, the distribution of cphA among aeromonads is species-specific, found in A. aquariorum, A. veronii and A. hydrophila, and the MHT may be a phenotypic screening test for CphA production., UL https://www.microbiologyresearch.org/content/journal/jmm/10.1099/jmm.0.038323-0