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Coagulase-negative staphylococci (CoNS) colonize human skin and mucosal membranes, which is why they are considered harmless commensal bacteria. Two species, Staphylococcus epidermidis and Staphylococcus haemolyticus belong to the group of CoNS species and are most frequently isolated from nosocomial infections, including device-associated healthcare-associated infections (DA-HAIs) and local or systemic body-related infections (FBRIs). Methicillin resistance, initially described in Staphylococcus aureus , has also been reported in CoNS species. It is mediated by the mecA gene within the staphylococcal cassette chromosome (SCC mec ). SCC mec typing, primarily using PCR-based methods, has been employed as a molecular epidemiological tool. However, the introduction of whole genome sequencing (WGS) and next-generation sequencing (NGS) has enabled the identification and verification of new SCC mec types. This review describes the current distribution of SCC mec types, subtypes, and variants among CoNS species, including S. epidermidis , S. haemolyticus , and S. capitis . The literature review focuses on recent research articles from the past decade that discuss new combinations of SCC mec in coagulase-negative Staphylococcus . The high genetic diversity and gaps in CoNS SCC mec annotation rules underscore the need for an efficient typing system. Typing SCC mec cassettes in CoNS strains is crucial to continuously updating databases and developing a unified classification system.

Growing antibiotic resistance of bacteria is a burning problem of human and veterinary medicine. Expansion and introduction of novel microbicidal therapeutics is highly desirable. However, antibiotic treatment disturbs the balance of physiological microbiota by changing its qualitative and/or quantitative composition, resulting in a number of adverse effects that include secondary infections. Although such dysbiosis may be reversed by the treatment with probiotics, a more attractive alternative is the use of antibiotics that target only pathogens, while sparing the commensals. Here, we describe lysostaphin LSp222, an enzyme produced naturally by Staphylococcus pseudintermedius 222. LSp222 is highly effective against S. aureus, including its multi-drug resistant strains. Importantly, the inhibitory concentration for S. epidermidis, the predominant commensal in healthy human skin, is at least two orders of magnitude higher compared to S. aureus. Such significant therapeutic window makes LSp222 a microbiota-friendly antibacterial agent with a potential application in the treatment of S. aureus-driven skin infections., (Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.)

Staphylococci are among the most frequent human microbiota components associated with the high level of bloodstream infection (BSI) episodes. In predisposed patients, there is a high risk of transformation of BSI episodes to sepsis. Both bacterial and host factors are crucial for the outcomes of BSI and sepsis. The highest rates of BSI episodes were reported in Africa, where these infections were up to twice as high as the European rates. However, there remains a great need to analyze African data for comprehensive quantification of staphylococcal BSI prevalence. The lowest rates of BSI exist in Australia. Asian, European, and North American data showed similar frequency values. Worldwide analysis indicated that both Staphylococcus aureus and coagulase-negative staphylococci (CoNS) are the most frequent BSI agents. In the second group, the most prevalent species was Staphylococcus epidermidis , although CoNS were not identified at the species level in many studies. The lack of a significant worldwide decrease in BSI episodes indicates a great need to implement standardized diagnostic methods and research etiological factors using advanced genetic methods., Competing Interests: Conflict of interest The authors do not report any financial or personal connections with other persons or organizations, which might negatively affect the contents of this publication and/or claim authorship rights to this publication., (© 2021 Klaudia Lisowska-Łysiak et al.)

This review article shows that coagulase-negative staphylococci (CoNS) are widely responsible for laryngological diseases. General characteristics of CoNS infections are shown in the introduction, and the pathogenicity in terms of virulence determinants, biofilm formation and genetic regulation mechanisms of these bacteria is presented in the first part of the paper to better display the virulence potential of staphylococci. The PubMed search keywords were as follows: CoNS and: nares infections, nasal polyps, rhinosinusitis, necrosing sinusitis, periprosthetic joint infection, pharyngitis, osteomyelitis of skull and neck bones, tonsillitis and recurrent tonsillitis. A list of laryngological infections and those related to skull and neck bones was presented with descriptions of the following diseases: rhinosinusitis, necrotizing sinusitis, nasal polyps, nares and nasal skin infections, periprosthetic joint infections, osteomyelitis, pharyngitis, and tonsillitis. Species identification and diagnostic problems challenging for diagnosticians are presented. Concluding remarks regarding the presence of CoNS in humans and their distribution, particularly under the effect of facilitating factors, are mentioned.

Many members of the Staphylococcus genus are clinically relevant opportunistic pathogens that warrant accurate and rapid identification for targeted therapy. The aim of this study was to develop a careful assignment scheme for staphylococcal species based on next-generation sequencing (NGS) of the 16S-23S rRNA region. All reference staphylococcal strains were identified at the species level using Sanger sequencing of the 16S rRNA , sodA, tuf , and rpoB genes and NGS of the 16S-23S rRNA region. To broaden the database, an additional 100 staphylococcal strains, including 29 species, were identified by routine diagnostic methods, 16S rRNA Sanger sequencing and NGS of the 16S-23S rRNA region. The results enabled development of reference sequences encompassing the 16S-23S rRNA region for 50 species (including one newly proposed species) and 6 subspecies of the Staphylococcus genus. This study showed sodA and rpoB targets were the most discriminative but NGS of the 16S-23S rRNA region was more discriminative than tuf gene sequencing and much more discriminative than 16S rRNA gene sequencing. Almost all Staphylococcus species could be distinguished when the max score was 99.0% or higher and the sequence similarity between the best and second best species was equal to or >0.2% (min. 9 nucleotides). This study allowed development of reference sequences for 21 staphylococcal species and enrichment for 29 species for which sequences were publicly available. We confirmed the usefulness of NGS of the 16S-23S rRNA region by identifying the whole species content in 45 clinical samples and comparing the results to those obtained using routine diagnostic methods. Based on the developed reference database, all staphylococcal species can be reliably detected based on the 16S-23S rRNA sequences in samples composed of both single species and more complex polymicrobial communities. This study will be useful for introduction of a novel diagnostic tool, which undoubtedly is an improvement for reliable species identification in polymicrobial samples. The introduction of this new method is hindered by a lack of reference sequences for the 16S-23S rRNA region for many bacterial species. The results will allow identification of all Staphylococcus species, which are clinically relevant pathogens.

Staphylococci are very common human and animal pathogens. A variety of staphylococcal virulence determinates leads to vast range of infections. One of them is mastitis which is a common disease of the mammary glands. The incidence of this disease is widespread all over the world and depends on bacterial virulence and on prevention programs. The influence of mastitis on human health is not globally evaluated, however, in veterinary fields loses in milk production caused by bovine mastitis are a constant economic problem. One of the most important parts of the mastitis control programs is accurate diagnosis of the inflammation and characterization of the etiological factors which leads to reduction of mastitis spread. Recent reports show that staphylococci are common bacterial etiological factors of mastitis, and this paper is an overview of the diagnostic typing methods used for characterization of staphylococcal isolates. A number of different techniques available to applicate is described. Phenotypic methods to identify and to differentiate isolates or discriminate virulence factors are still in use, however, some advanced genetic methods offering higher discriminatory power are reported as more accurate. In fact, nowadays the most powerful tool on that field is next generation sequencing (NGS) of the whole genome, but its high cost and requirement of special laboratory equipment makes it hard to use for routine diagnostics. That is why standard PCR techniques-based methods, and the sequencing of particular genes, are mostly used for typing bacterial isolates. Most of these techniques are characterized by a high discriminatory power, big epidemiological concordance, and repeatable results. The presented report describes the techniques used most frequent in mastitis diagnostics related to staphylococci typing and shows their advantages and disadvantages., (Copyright© by the Polish Academy of Sciences.)