Tatsuo Yamamoto

We report the transposition of a 9,045-bp transposon (Tn 552-II ) carrying the tnpABC /target-gene-like( tgl )/ blaZ-R1-I array to a conjugative plasmid (pCtra) in pediatric multidrug-resistant community-associated methicillin-resistant Staphylococcus aureus . Tn 552-II contained a 7-bp target site ( att ) on the left; an internal i-att on the right, apparently “brought-in” through a circular intermediate; and i-att2 and i-att3 in the tgl gene and its neighboring gene, respectively. This transposition enhanced ampicillin resistance and facilitated Tn 552-II spread at a frequency of 10 ⁻³ .

One of the formidable complications of SARS-COV-2 infection leading to death is coagulopathy. The mechanisms of the development of this pathology at the present stage have not been studied, and clinical blood tests indicate that against the background of normal blood clotting indices, only the Ddi-D-dimer protein exceeds the norm many times over. The aim of the study was to study and analyze biochemical parameters in patients of Primorsky Region (Russia) infected with SARS-COV-2 against the background of concomitant vascular pathology and the development of DIC syndrome. The authors came to the conclusion about the existence of two mechanisms of circulatory disorders in the vessels of the microvasculature, associated with the violation of the integrity of the vascular wall and destruction of erythrocytes. Further research is needed to study the mechanisms of SARS-CoV-2 aggression, leading to thrombotic complications.

Methicillin-resistant Staphylococcus aureus (MRSA) is a major multidrug-resistant bacterial pathogen. The evolution of MRSA is dynamic posing an ongoing threat to humans. The evolution of MRSA includes horizontal gene transfer, which is mediated by mobile genetic elements, plasmids, and bacteriophages, and also mutations. In this review, we clarify the recent trends in MRSA from the perspectives of drug-resistance transfer and uncontrollable infections, particularly those occurring in community settings. We first address the role of MRSA as a disseminator of multidrug resistance. We have studied the cell-to-cell transfer of drug resistance, in which transfer frequencies range from 10-3 to 10-8. The mechanisms of drug-resistance transfers include the self-transmission of large plasmids, the mobilization of small nonconjugative plasmids, the generalized transduction of phages, and the transfer of transposons with circular intermediates. We then discuss uncontrollable infections. Although several anti-MRSA agents have been developed, uncontrollable cases of MRSA infections are still reported. Examples include a case of uncontrollable sepsis arising from a community-associated MRSA (CA-MRSA) with the ST8/SCCmecIVl genotype, and a relapsing severe invasive infection of ST30/SCCmecIVc CA-MRSA in a student athlete. Some of these cases may be attributable to unique adhesins, superantigens, or cytolytic activities. The delayed diagnosis of highly adhesive and toxic infections in community settings may result in CA-MRSA diseases that are difficult to treat. Repeated relapse, persistent bacteremia, and infections of small-colony variants may occur. To treat MRSA infections in community settings, these unique features of MRSA must be considered to ensure that diagnostic delay is avoided.

The cell wall‐anchored protein‐encoding spj gene on staphylococcal cassette chromosome mec IVl (SCCmecIVl) was found to vary in size because of its 22‐ and 86‐aa repeat domains. The 22‐aa repeats are the more flexible of the two repeats, comprising three 11‐aa units, and were classified into three groups with eleven types. The 11/22‐aa repeats are longer in individuals with bullous impetigo, shorter in those with invasive disease and were absent in a fatal case, this last one having been rapidly diagnosed by PCR. IS431‐flanking pUB110 (bleO, aadD) is present on SCCmecIVl at 90%. The bacterial surface has the spj product and a unique surface layer.