Resistome of a carbapenemase-producing novel ST232 Klebsiella michiganensis isolate from urban hospital effluent in South Africa

Objectives: Klebsiella michiganensis is an emerging pathogen implicated in nosocomial infections. Here we report on the resistome, virulome and mobilome of a carbapenemase-producing K. michiganensis isolate from urban hospital effluent in Pietermaritzburg, KwaZulu-Natal, South Africa. Klebsiella sp. isolate KP124 was originally isolated from the final effluent of an urban tertiary hospital in Pietermaritzburg, KwaZulu-Natal. Methods: Following phenotypic characterisation and antibiotic susceptibility testing, the genome of carbapenemase-producing isolate KP124 was sequenced using an Illumina MiSeq platform, de novo assembled and analysed using established bioinformatics tools. Results: The draft genome of strain KP124 was 6 544 586 bp in length, comprising 203 contigs >200 bp. Following confirmation of isolate KP124 as K. michiganensis using reference genomes, the blaOXA-181 carbapenemase gene as well as 11 additional genes encoding resistance against β-lactams, aminoglycosides, fluoroquinolones and sulfonamides were detected. Virulence factors enabling iron acquisition and cell adherence, capsule locus type and plasmid replicon types were identified. Conclusion: This study represents the first report of an OXA-181 carbapenemase-producing K. michiganensis isolate from hospital effluent in South Africa. The presence of such a strain in the environment owing to the absence of hospital effluent treatment presents a potential risk to informal communities that may use contaminated surface water domestically

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Not AvailableShiga toxigenic Escherichia coli (STEC) O157 and several other serogroups of non-O157 STEC strains present as commensalism bacteria in small ruminants that possess a high potential of attaining pathogenic virulent genetic elements. The pathogenicity of non-O157 strains is emerging progressively in animals as well as in humans especially in the rural areas as they get transmitted through unsanitary practices of living, consumption of uncooked meat and milk, human-livestock close proximity as well as within livestock pathogenic bacterial transmission. The present study was carried out to determine the prevalence of non-O157 E.coli isolates and characterize based on clinical history, antibiotic sensitivity testing, multiplex PCR (mPCR) detection of virulence genes, genotype identification using pulse field gel electrophoresis (PFGE) and polyacrylamide gel electrophoretic separation of antigenic proteins to determine their prevalence, virulence and genetic comparison between host and environment for epidemiological significance. A total of 300 E.coli isolates were recovered from rectal swabs of goats and their surrounding environment over a period of one year (2016–2017) by selective isolation. Among which 50 isolates were confirmed to be from the non-O157 E.coli family. The mPCR analysis of these 50 isolates revealed the presence of two or more virulent genes, viz., hylA (90%), fliC (74%), eaeA (56%), stx1 (48%) and stx2 (22%).Four isolates exhibited multidrug-resistance to amoxiclav, doxycycline, ciprofloxacin and ceftriazone. The PFGE fingerprint profile showed six major clusters at 100% similarity from the 50 isolates. The major antigenic proteins identified from the isolates were stx1A, stx2B and fliC. This study has significant implications for understanding the molecular diversity of emerging pathotypes of non-O157 in young goats in terms of virulence and epidemiological aspects.Not Availabl

Exopolymeric substances (EPS) from Salmonella enterica: polymers, proteins and their interactions with plants and abiotic surfaces

When Salmonella enterica is not in a planktonic state, it persists in organised communities encased in extracellular polymeric substances (EPS), defined as biofilms. Environmental conditions ultimately dictate the key properties of the biofilms such as porosity, density, water content, charge, sorption and ion exchange properties, hydrophobicity and mechanical stability. S. enterica has been extensively studied due to its ability to infect the gastrointestinal environment. However, only during the last decades studies on its persistence and replication in soil, plant and abiotic surfaces have been proposed. S. enterica is an environmental bacterium able to effectively persist outside the human host. It does so by using EPS as tools to cope with environmental fluctuations. We therefore address this mini-review to classify those EPS that are produced by Salmonella with focus on the environment (plant, soil, and abiotic surfaces) by using a classification of EPS proposed by Flemming and collaborators in 2007. The EPS are therefore classified as structural, sorptive, surface-active, active, and informative