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Carbapenemase-producing Alcaligenes species has been described in only few studies, with none so far from the African continent. Here, we report the whole genome sequence of P e analcaligenes suwonensis bearing bla VIM-5 metallo-β-lactamase and first detection of carbapenemase producing Alcaligenes faecalis isolated from patients attending tertiary healthcare facilities in Nigeria. The isolates were identified by MALDI-TOF Mass Spectrometry. Antibiotic susceptibility assay, modified Carba NP test and genomic investigation revealed that two isolates of Alcaligenes faecalis and an isolate of Paenalcaligenes suwonensis harboured bla VIM-5 gene. The genome sequence analysis of the P. suwonensis 191B isolate, responsible for acute gastroenteritis, reveal the presence of 18 antibiotic resistance genes coding for resistance to five different classes of antibiotics. Three of the genes (bla OXA-368 , bla CARB-4 and bla VIM-5) codes for resistance to β-lactam antibiotics. To our best knowledge, we describe here the first genome sequence of P. suwonensis species and the first detection of class B carbapenemase bla VIM-5 in a clinical isolate of P. suwonensis species and Alcaligenes faecalis in Nigeria. The finding of this study is of concern, as lateral dissemination of the genes into clinically important Gram-negative pathogens is highly likely. • Molecular characterization of clinical multidrug resistant isolates of Alcaligenes species from Sokoto hospital, Nigeria. • First description of Paenalcaligenes suwonensis strain bearing bla VIM-5 carbapenemase, responsible for acute gastroenteritis. • Description of first whole-genome sequences of Paenalcaligenes suwonensis species and its full resistome. [ABSTRACT FROM AUTHOR]

• First report of mcr-1 in Alcaligenes faecalis and of mcr-5 and mcr-8 in Nigeria. • 17.0% of isolates from humans and animals were resistant to colistin. • MIC > 64 μg/mL in 6/8 mcr + human K. pneumoniae and 2/9 mcr + animal E. coli. Colistin is a last-resort drug used to treat infections caused by multidrug-resistant Gram-negative bacteria that have developed carbapenem resistance. Emergence and rapid dissemination of the nine plasmid-mediated mobile colistin resistance genes (mcr-1 to mcr-9) has led to fear of pandrug-resistant infections worldwide. To date, there is only limited information on colistin resistance in African countries where the drug is widely used in agriculture. In this Nigerian study, 583 non-duplicate bacterial strains were isolated from 1119 samples from humans, camels, cattle, dogs, pigs and poultry using colistin-supplemented MacConkey agar, among which 17.0% (99/583) were colistin-resistant. PCR (mcr-1 to mcr-9) and whole-genome sequencing (WGS) identified mcr in 21.2% (21/99) of colistin-resistant isolates: mcr-1.1 (n = 13), mcr-8.1 (n = 5), mcr-1.1 and mcr-8.1 (n = 2), and mcr-1.1 and mcr-5 (n = 1). Of the 21 mcr -positive strains, 9 were isolated from human samples, with 8 being Klebsiella pneumoniae , and 6 of these human K. pneumoniae had a high colistin MIC (>64 μg/mL). In contrast, 9 of the 12 mcr -positive animal isolates were Escherichia coli , of which only 2 had a colistin MIC of >64 μg/mL. This study is the first to report mcr-1 in Alcaligenes faecalis and the emergence of mcr-5 and mcr-8 in Nigeria. WGS determined that mcr-1 was localised on an IncX4 plasmid and that 95.2% of mcr-1 harbouring isolates (20/21) transferred colistin resistance successfully by conjugation. These findings highlight the global spread of colistin resistance and emphasise the urgent need for co-ordinated global action to combat resistant bacteria. [ABSTRACT FROM AUTHOR]