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This study investigated the molecular characteristics of urinary carbapenemase-producing Klebsiella pneumoniae isolates (n = 194) in Gauteng, South Africa, using simple, cost-effective PCR methodologies. Extensively drug resistant (XDR) ST307 with blaOXA-181 on IncX3 plasmids was endemic in Gauteng community hospitals leaving limited options for treating in- and outpatient urinary tract infections. High-level ceftazidime/avibactam resistance was detected among isolates harbouring blaOXA-48-like including blaOXA-181. These findings highlighted the need for genomic methodologies suitable for lower- and middle-income countries to track XDR clones and plasmids in community hospitals. Such results will aid with treatment and stewardship strategies. [ABSTRACT FROM AUTHOR]

Plastitar has recently been reported in marine environments worldwide. Plastitar is plastic embedded in crude oil residues. This plastic form, i.e., geochemically or - physically altered plastic, has been proposed to derive from water motion driven plastic-crude oil-interactions in pelagic and benthic habitats. In this study, we introduce bitumen-based plastitar: a novel plastic form variant that we detected in supra-intertidal marina walls, riverbank cobblestone pavements, and roads. Fourier-transform infrared (FTIR) spectroscopy identified plastic fragments, bottle cap plastic liners, and paint chips, that we had found firmly embedded in black joint sealant, as polypropylene, polyethylene, polyester epoxide, and alkyd varnish. Field observations, pyrolysis-gas chromatography/mass spectroscopy (PY-GC/MS) and FTIR indicated that the black joint sealant consisted of a bitumen-mineral-mixture that is commonly used as adhesive and filler in hydraulic engineering and road construction. Brittle plastic fragments showed signs of melting such as bubbles, holes, and melt inclusions and, therefore, constituted pyroplastics, i.e., incompletely combusted and melted plastics with rock-like appearances. Bottle caps and paint chips were deeply pressed into the joint sealant. These findings indicate that bitumen-based plastitar is formed by plastic being (un)intentionally included into heated liquid bitumen or pressed into hardened bitumen. Our field inspections detected that bitumen-based plastitar degraded by up to 66% over 608 days releasing microplastics (plastics < 0.5 cm) into the environment. Overall, our study shows, for the first time, that plastitar variants can form from materials other than crude oil residues and in terrestrial environments. We hope that our study will increase the awareness for these novel plastic fixation processes, i.e., plastic agglomeration with bitumen through heat and pressure, which could help to prevent plastitar formation during future construction works. [ABSTRACT FROM AUTHOR]

Purpose: The emergence of carbapenem-resistant P. aeruginosa (CRPA) harbouring acquired carbapenemase genes (blaVIM, blaIMP and blaNDM) has become a global public health threat. Three CRPA isolates included in the study had an extensively drug-resistant phenotype with susceptibility to colistin only and were positive for the blaNDM-1 gene. The current study aimed to investigate the genomic epidemiology and molecular characteristics of the blaNDM-1-positive CRPA isolates collected from the Gauteng region, South Africa. Methods: Short read whole genome sequencing (WGS) was performed to determine sequence types (STs), genetic relatedness, resistome, virulome and the genetic environment of the blaNDM-1 gene. Results: The WGS and phylogenetic analyses revealed that the study isolates belonged to an international high-risk clone ST773 and belonged to the same clade with eight blaNDM-1-positive ST773 isolates from Hungary, India, Nigeria, South Korea and USA. The study isolates harboured a wide repertoire of intrinsic and acquired antibiotic resistance genes (ARGs) related with mobile genetic elements, porins and efflux pumps, as well as virulence factor genes. The clade-specific ARGs (blaNDM-1, floR2/cmlA9, rmtB4, tetG) were found in a putative integrative and conjugative element (ICE) region similar to ICE6660-like. Conclusion: As ICE carrying the blaNDM-1 gene can easily spread to other P. aeruginosa isolates and other Gram-negative bacteria, the findings in this study highlight the need for appropriate management strategies and active surveillance of CRPA isolates in the Gauteng region, South Africa. [ABSTRACT FROM AUTHOR]

In a note at the 1928 International Congress of Mathematicians Cartan outlined how his “method of equivalence” can provide the invariants of nonholonomic systems on a manifold 𝑄 with kinetic lagrangians [29]. Cartan indicated which changes of the metric outside the constraint distribution 𝐸 ⊂ 𝑇𝑄 preserve the nonholonomic connection 𝐷𝑋𝑌 = Proj𝐸 ∇𝑋𝑌, 𝑋,𝑌 ∈ 𝐸, where ∇𝑋𝑌 is the Levi-Civita connection on 𝑄 and Proj𝐸 is the orthogonal projection over 𝐸. Here we discuss this equivalence problem of nonholonomic connections for Chaplygin systems [30,31,62]. We also discuss an example-a mathematical gem!-found by Oliva and Terra [76]. It implies that there is more freedom (thus more opportunities) using a weaker equivalence, just to preserve the straightest paths: 𝐷𝑋𝑋 = 0. However, finding examples that are weakly but not strongly equivalent leads to an over-determined system of equations indicating that such systems should be rare. We show that the two notions coincide in the following cases: i) Rank two distributions. This implies for instance that in Cartan’s example of a sphere rolling on a plane without slipping or twisting, a (2,3,5) distribution, the two notions of equivalence coincide; ii) For a rank 3 or higher distribution, the corank of D in D+[D,D] must be at least 3 in order to find examples where the two notions of equivalence do not coincide. This rules out the possibility of finding examples on (3,5) distributions such as Chaplygin’s marble sphere. Therefore the beautiful (3,6) example by Oliva and Terra is minimal. 1.

The World Health Organization recently identified global spread of antimicrobial resistance (AMR) as one of the most serious recent threats to human health (1). The emergence and spread of carbapenem [...]