Urban riverine environment is a source of multidrug-resistant and ESBL-producing clinically important Acinetobacter spp.
Some Acinetobacter species have emerged as very important opportunistic pathogens in humans. We investigated Acinetobacter spp. from the polluted urban riverine environment in Croatia in regard to species affiliation, antibiotic resistance pattern, and resistance mechanisms. Considerable number of isolates produced acquired extended-spectrum β-lactamase(s) (ESBLs), CTX-M-15 solely or with TEM-116. By Southern blot hybridization, bla TEM-116 was identified on plasmids ca. 10, 3, and 1.2 kb in Acinetobacter junii, A. gandensis, and A. johnsonii. The bla TEM-116-carrying plasmid in A. gandensis was successfully transferred by conjugation to azide-resistant Escherichia coli J53. A. radioresistens isolate also carried an intrinsic carbapenemase gene bla OXA-133 with ISAba1 insertion sequence present upstream to promote its expression. Majority of ESBL-producing isolates harbored integrases intI1 and/or intI2 and the sulfamethoxazole resistance gene sul1. Almost all isolates had overexpressed resistance-nodulation-cell division (RND) efflux system, indicating that this mechanism may have contributed to multidrug resistance phenotypes. This is the first report of environmental CTX-M-15-producing Acinetobacter spp. and the first identification of CTX-M-15 in A. johnsonii, A. junii, A. calcoaceticus, A. gandensis, A. haemolyticus, and A. radioresistens worldwide. We identified, also for the first time, the environmental Acinetobacter-producing TEM ESBLs, highlighting the potential risk for human health, and the role of these bacteria in maintenance and dissemination of clinically important antibiotic resistance genes in community through riverine environments.
Department of Biology, Faculty of Science, University of Split, Teslina 12, 21000, Split, Croatia. ana.maravic@pmfst.hr.
Ana
A
Maravić
Department of Biology, Faculty of Science, University of Split, Teslina 12, 21000, Split, Croatia.
Mirjana
M
Skočibušić
Department of Biology, Faculty of Science, University of Split, Teslina 12, 21000, Split, Croatia.
Željana
Ž
Fredotović
Department of Biology, Faculty of Science, University of Split, Teslina 12, 21000, Split, Croatia.
Ivica
I
Šamanić
Department of Molecular Biology, Ruđer Bošković Institute, Bijenička 54, 10000, Zagreb, Croatia.|Mediterranean Institute for Life Sciences, Meštrovićevo šetalište 45, 21000, Split, Croatia.
Svjetlana
S
Cvjetan
Department of Biology, Faculty of Science, University of Split, Teslina 12, 21000, Split, Croatia.
Mia
M
Knezović
Department of Biology, Faculty of Science, University of Split, Teslina 12, 21000, Split, Croatia.
Jasna
J
Puizina
D000150:Acinetobacter / Q000187:drug effects / Q000201:enzymology / Q000235:genetics / Q000302:isolation & purification*; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D017523:Croatia; D024901:Drug Resistance, Multiple, Bacterial / Q000187:drug effects / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D005798:Genes, Bacterial; D019015:Geologic Sediments / Q000382:microbiology; D006801:Humans; D008826:Microbial Sensitivity Tests; D010802:Phylogeny; D010957:Plasmids; D016133:Polymerase Chain Reaction; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D045483:Rivers / Q000382:microbiology*; D014507:Urbanization; D001618:beta-Lactamases / Q000096:biosynthesis* / Q000235:genetics
D000900:Anti-Bacterial Agents; D012336:RNA, Ribosomal, 16S; D001618:beta-Lactamases
Acinetobacter; Beta lactamase; CTX-M-15; ESBL; River environment; TEM-116