Măciucă Iulia Elena

Prevalence and Characterisation of Extended-Spectrum Beta-Lactamases and Plasmid-Mediated Quinolones Resistance in Enterobacteriaceae Isolated from Companion Animals

Andreea Paula Cozma, Iulia Elena Măciucă, Cristina Mihaela Rîmbu, Ioana Crivei, Șerban Moroșan, Lucia Carmen Trincă, Dorina Timofte

ABSTRACT. Antimicrobial resistance is a major public health concern worldwide. This study aims to determine the prevalence of Enterobacterales producing beta-lactamase (TEM, SHV, OXA) or extended-spectrum beta-lactamases (ESBL), as well as plasmid-mediated resistance to quinolones (PMQR) (qnrA, qnrB, qnrS) in companion animals from the northeast region of Romania. A total of 124 faecal samples were collected aseptically from healthy dogs attending the veterinary practice for vaccination and cultivated on Brilliance ESBL medium (Oxoid, UK). The ESBL production testing was performed using the combination disc test. The identification of Enterobacterales strains was achieved using molecular identification and based on biochemical tests. Antimicrobial susceptibility testing was performed using the disk diffusion method. Identification of genes encoding for beta-lactamase enzymes and genes encoding plasmid-mediated resistance to quinolones was performed by PCR according to the protocols previously described. After ESBL screening, 31 (31/124; 25%) extended-spectrum cephalosporin (ESC)-resistant Enterobacterales were obtained, and 67.74% (21/31) of them were confirmed as ESBL-producers. Regarding the Enterobacterales species, 27 (27/31; 87.1%) were Escherichia coli and 4 (4/31; 12.9%) strains were Klebsiella pneumoniae. Among the ESBL-producing isolates, the blaCTX-M-1 gene group was predominant (58.82%), followed by the blaCTX-M-9 group (41.18%). The blaTEM, blaSHV and blaOXA gene groups were identified in 54.83%, 29.03% and 3.22% of the analysed strains, respectively. The prevalence of PMQR genes was 22.58% and consisted only of qnrS (19.35%) and qnrA (3.22%) genes. The prevalence of ESBL strains related to the total number of analysed samples was 16.93% (21/124). The findings show a significant prevalence of ESBLs and PMQR genes in Enterobacterales strains isolated from the faeces of healthy dogs, implying that pets may pose a risk of transmitting ESBL strains to other animals or owners.

Keywords: antimicrobial resistance; companion animals; ESBL genes.

Abstract published in Conference Programme dedicated to LIFE SCIENCES TODAY FOR TOMORROW

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Increased Tolerance to Chlorhexidine Following Prolonged Exposure in Staphylococcus Species Isolated from the Skin and Mucosae of Dogs

Ozana-Maria Hrițcu, Gheorghe Solcan, Iuliana E. Măciucă, Dorina Timofte, Vanessa Schmidt

ABSTRACT. This study aimed to investigate if canine staphylococci isolates could develop tolerance to chlorhexidine digluconate after long-term exposure. Staphylococci (Staphylococcus pseudintermedius and coagulase-negative staphylococci, methicillin-susceptible and methicillin-resistant), with and without genotypic chlorhexidine resistance, were investigated for phenotypic chlorhexidine tolerance by determining the MBC (minimal bactericidal concentration) at various time points. The testing was performed as follows: determination of MBC for 30 minutes and 24 hours (MBC 24h-1); exposure of isolates for seven days to concentrations of chlorhexidine equal to 1/2 MBC 24h-1; determination of MBC for 24 h after the first week (MBC 24h-2); exposure of isolates for seven days to concentrations of chlorhexidine equal to 1/2 MBC 24h-2 and rest in Mueller–Hinton broth for seven days; determination of MBC for 24 h after the second week (MBC 24h-3). The MBC for 30 minutes ranged between 16–32 µg/ml compared to the MBC 24h-1 which was between 1–8 µg/ml. The MBCs for 24 h dropped from 8 µg/ml to 0.5 µg/ml for isolate 1, from 2 µg/ml to1 µg/ml for isolate 6 and from 2 µg/ml to 0.5 µg/ml for isolate 8 after being exposed for seven days to concentrations of chlorhexidine equal to 1/2 MBC 24h-1. For one CoNS (coagulase-negative staphylococci), the MBC 24h-2 increased four times from 1 µg/ml (MBC 24h-1) to 4 µg/ml and dropped again to 1 µg/ml after the second week. These results suggest that continuous exposure to chlorhexidine could lead to the selection of chlorhexidine-tolerant staphylococci that could withstand concentrations used during routine decolonisation procedures.

Keywords: Staphylococcus; chlorhexidine; tolerance; MBC.

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