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10 pages, 504 KiB

Open AccessCommunication

Phenotypic and Genotypic Assays to Evaluate Coagulase-Negative Staphylococci Biofilm Production in Bloodstream Infections

by Giulia Grassia, Jessica Bagnarino, Mariangela Siciliano, Daniela Barbarini, Marta Corbella, Patrizia Cambieri, Fausto Baldanti and Vincenzina Monzillo

Microorganisms 2024, 12(1), 126; https://doi.org/10.3390/microorganisms12010126 - 08 Jan 2024

Viewed by 703

Abstract

Coagulase-negative staphylococci (CoNS) are commensal on human body surfaces and, for years, they were not considered a cause of bloodstream infection and were often regarded as contamination. However, the involvement of CoNS in nosocomial infection is increasingly being recognized. The insertion of cannulas [...] Read more.

Coagulase-negative staphylococci (CoNS) are commensal on human body surfaces and, for years, they were not considered a cause of bloodstream infection and were often regarded as contamination. However, the involvement of CoNS in nosocomial infection is increasingly being recognized. The insertion of cannulas and intravascular catheters represents the primary source of CoNS entry into the bloodstream, causing bacteremia and sepsis. They owe their pathogenic role to their ability to produce biofilms on surfaces, such as medical devices. In this study, we evaluate the adhesive capacity of CoNS isolated from blood cultures by comparing a spectrophotometric phenotypic assay with genotypic analysis based on the evidence of the ica operon. We retrospectively reviewed the database of CoNS isolated from blood cultures from January to December 2021 that were considered responsible for 361 bloodstream infections. Eighty-nine CoNS were selected among these. Our data show that Staphylococcus epidermidis was the predominant species isolated, expressing greater adhesive capacities, especially those with the complete operon. Knowledge of the adhesive capabilities of a microorganism responsible for sepsis can be useful in implementing appropriate corrective and preventive measures, since conventional antibiotic therapy cannot effectively eradicate biofilms. Full article

(This article belongs to the Special Issue Characterisation and Molecular Analysis of Staphylococcal Species: Their Impact on Colonization and Infection)

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16 pages, 5461 KiB

Open AccessArticle

Roles of the Crp/Fnr Family Regulator ArcR in the Hemolysis and Biofilm of Staphylococcus aureus

by Tongtong Fu, Zheng Fan, Yujie Li, Zhoufei Li, Hanqing Zhao, Yanling Feng, Guanhua Xue, Jinghua Cui, Chao Yan, Lin Gan, Junxia Feng, Jing Yuan and Fuping You

Microorganisms 2023, 11(7), 1656; https://doi.org/10.3390/microorganisms11071656 - 25 Jun 2023

Cited by 1 | Viewed by 1372

Abstract

Staphylococcus aureus is an opportunistic human pathogen that is often involved in severe infections such as pneumonia and sepsis in which bacterial virulence factors play a key role. Infections caused by S. aureus are often difficult to eradicate, particularly when they are associated [...] Read more.

Staphylococcus aureus is an opportunistic human pathogen that is often involved in severe infections such as pneumonia and sepsis in which bacterial virulence factors play a key role. Infections caused by S. aureus are often difficult to eradicate, particularly when they are associated with biofilm. The physiological roles of the Crp/Fnr family regulator ArcR are elusive in S. aureus. In this study, it was found that the deletion of arcR increased the hemolytic ability and biofilm formation in S. aureus. Differential gene expression analysis by RNA-seq and real-time quantitative reverse transcription PCR showed that genes associated with hemolytic ability (hla and hlb) and biofilm formation (icaA, icaB, icaC and icaD) were significantly upregulated compared with those in the wild-type strain. The results revealed that ArcR regulated the expression of the hla and ica operon by binding to their promoter regions, respectively. This study provided new insights into the functional importance of ArcR in regulating the virulence and biofilm of S. aureus. Full article

(This article belongs to the Special Issue Characterisation and Molecular Analysis of Staphylococcal Species: Their Impact on Colonization and Infection)

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16 pages, 1518 KiB

Open AccessArticle

Molecular Characterization of Staphylococcus aureus Isolated from Raw Milk and Humans in Eastern Tanzania: Genetic Diversity and Inter-Host Transmission

by Tutu Mzee, Happiness Kumburu, Theckla Kazimoto, Pimlapas Leekitcharoenphon, Marco van Zwetselaar, Rose Masalu, Tarsis Mlaganile, Tolbert Sonda, Boaz Wadugu, Ignass Mushi, Frank M. Aarestrup and Mecky Matee

Microorganisms 2023, 11(6), 1505; https://doi.org/10.3390/microorganisms11061505 - 05 Jun 2023

Cited by 3 | Viewed by 1862

Abstract

Staphylococcus aureus is a common cause of infection in humans and animals, including bovine mastitis, globally. The objective of this study was to genetically characterize a collection of S. aureus isolates recovered from milk and nasal swabs from humans with and without animal [...] Read more.

Staphylococcus aureus is a common cause of infection in humans and animals, including bovine mastitis, globally. The objective of this study was to genetically characterize a collection of S. aureus isolates recovered from milk and nasal swabs from humans with and without animal contact (bovine = 43, human = 12). Using whole genome sequencing (NextSeq550), isolates were sequence typed, screened for antimicrobial resistance and virulence genes and examined for possible inter-species host transmission. Multi locus sequence typing (MLST) and single nucleotide polymorphism (SNP)-based phylogeny revealed 14 different sequence types, including the following six novel sequence types: ST7840, 7841, 7845, 7846, 7847, and 7848. The SNP tree confirmed that MLST clustering occurred most commonly within CC97, CC5477, and CC152. ResFinder analysis revealed five common antibiotic resistance genes, namely tet(K), blaZ, dfrG, erm©, and str, encoding for different antibiotics. mecA was discovered in one human isolate only. Multidrug resistance was observed in 25% of the isolates, predominantly in CC152 (7/8) and CC121 (3/4). Known bovine S. aureus (CC97) were collected in humans and known human S. aureus lineages (CC152) were collected in cattle; additionally, when these were compared to bovine-isolated CC97 and human-isolated CC152, respectively, no genetic distinction could be observed. This is suggestive of inter-host transmission and supports the need for surveillance of the human–animal interface. Full article

(This article belongs to the Special Issue Characterisation and Molecular Analysis of Staphylococcal Species: Their Impact on Colonization and Infection)

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12 pages, 504 KiB

Open AccessArticle

Mandatory Notification of Panton–Valentine Leukocidin-Positive Methicillin-Resistant Staphylococcus aureus in Saxony, Germany: Analysis of Cases from the City of Leipzig in 2019

by Utta Helbig, Constance Riemschneider, Guido Werner, Nancy Kriebel and Franziska Layer-Nicolaou

Microorganisms 2023, 11(6), 1437; https://doi.org/10.3390/microorganisms11061437 - 29 May 2023

Viewed by 1268

Abstract

In Germany, Saxony is the only federal state where the detection of a Panton–Valentine Leukocidin (PVL)-positive Methicillin-resistant Staphylococcus aureus (MRSA) has to be notified to the local health authority (LHA). The LHA reports the case to the state health authority and introduces concrete [...] Read more.

In Germany, Saxony is the only federal state where the detection of a Panton–Valentine Leukocidin (PVL)-positive Methicillin-resistant Staphylococcus aureus (MRSA) has to be notified to the local health authority (LHA). The LHA reports the case to the state health authority and introduces concrete infection control measures. We analyzed isolates from the respective cases in 2019, which were collected in local microbiological laboratories and sent to the National Reference Centre (NRC) for Staphylococci and Enterococci for strain characterization and typing. Antibiotic resistance testing was done by broth microdilution. Molecular characterization was performed using spa and SCCmec typing, MLST, and the PCR detection of marker genes associated with distinct MRSA lineages. Demographic and clinical data of the individual cases were assessed and the LHA performed epidemiological investigations. Thirty-nine (index) persons, diagnosed with a PVL-positive MRSA, were initially reported to the LHA. Most patients suffered from skin and soft-tissue infections (SSTI). For 21 of the index cases, household contacts were screened for MRSA. Seventeen out of 62 contacts were also colonized with a PVL-positive MRSA. The median age of altogether 58 individuals was 23.5 years. In over half of the cases, the home country was not Germany and/or a history of travel or migration was reported. Molecular characterization revealed the presence of various epidemic community-associated MRSA lineages, with “USA300”, including the North American Epidemic (ST8-MRSA-IVa) and the South American Epidemic Clone (ST8-MRSA-IVc), the “Sri Lankan Clone” (ST5-MRSA-IVc), and the “Bengal Bay Clone” (ST772-MRSA-V) being more prevalent. In eight out of nine households, the contact persons were colonized with the same clone as the respective index case, suggesting a close epidemic and microbiological link. The obligation to report PVL-positive MRSA enables us to detect the occurrence of PVL-producing MRSA and its spread in the population as early as possible. Timely detection allows the targeted deployment of reliable anti-infective measures. Full article

(This article belongs to the Special Issue Characterisation and Molecular Analysis of Staphylococcal Species: Their Impact on Colonization and Infection)

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16 pages, 2616 KiB

Open AccessArticle

Extraction of High-Quality RNA from S. aureus Internalized by Endothelial Cells

by Michelle Maurer, Tilman E. Klassert, Bettina Löffler, Hortense Slevogt and Lorena Tuchscherr

Microorganisms 2023, 11(4), 1020; https://doi.org/10.3390/microorganisms11041020 - 13 Apr 2023

Viewed by 2369

Abstract

Staphylococcus aureus evades antibiotic therapy and antimicrobial defenses by entering human host cells. Bacterial transcriptomic analysis represents an invaluable tool to unravel the complex interplay between host and pathogen. Therefore, the extraction of high-quality RNA from intracellular S. aureus lays the foundation to [...] Read more.

Staphylococcus aureus evades antibiotic therapy and antimicrobial defenses by entering human host cells. Bacterial transcriptomic analysis represents an invaluable tool to unravel the complex interplay between host and pathogen. Therefore, the extraction of high-quality RNA from intracellular S. aureus lays the foundation to acquire meaningful gene expression data. In this study, we present a novel and straightforward strategy to isolate RNA from internalized S. aureus after 90 min, 24 h, and 48 h postinfection. Real-time PCR data were obtained for the target genes agrA and fnba, which play major roles during infection. The commonly used reference genes gyrB, aroE, tmRNA, gmk, and hu were analyzed under different conditions: bacteria from culture (condition I), intracellular bacteria (condition II), and across both conditions I and II. The most stable reference genes were used for the normalization of agrA and fnbA. Delta C_q (quantification cycle) values had a relatively low variability and thus demonstrated the high quality of the extracted RNA from intracellular S. aureus during the early phase of infection. The established protocol allows the extraction and purification of intracellular staphylococcal RNA while minimizing the amount of host RNA in the sample. This approach can leverage reproducible gene expression data to study host–pathogen interactions. Full article

(This article belongs to the Special Issue Characterisation and Molecular Analysis of Staphylococcal Species: Their Impact on Colonization and Infection)

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12 pages, 435 KiB

Open AccessArticle

Virulence Potential and Antibiotic Susceptibility of S. aureus Strains Isolated from Food Handlers

by Adriana Fernandes, Carla Ramos, Victor Monteiro, Joana Santos and Paulo Fernandes

Microorganisms 2022, 10(11), 2155; https://doi.org/10.3390/microorganisms10112155 - 30 Oct 2022

Cited by 6 | Viewed by 1933

Abstract

Staphylococcus spp. are common members of the normal human flora. However, some Staphylococcus species are recognised as human pathogens due to the production of several virulence factors and enterotoxins that are particularly worrisome in food poisoning. Since many of Staphylococcal food poisoning outbreaks [...] Read more.

Staphylococcus spp. are common members of the normal human flora. However, some Staphylococcus species are recognised as human pathogens due to the production of several virulence factors and enterotoxins that are particularly worrisome in food poisoning. Since many of Staphylococcal food poisoning outbreaks are typically associated with cross-contamination, the detection of S. aureus on food handlers was performed. Hand swabs from 167 food handlers were analysed for the presence of S. aureus. More than 11% of the samples were positive for S. aureus. All S. aureus strains were isolated and analysed for the presence of virulence and enterotoxin genes, namely, sea, seb, sec, sed, seg, sei, tsst-1 and pvl. The same strains were phenotypically characterised in terms of antibiotic susceptibility using the disc diffusion method and antimicrobial agents from 12 different classes. A low prevalence of antibiotic-resistant strains was found, with 55.6% of the strains being sensitive to all of the antimicrobial agents tested. However, a high prevalence of resistance to macrolides was found, with 44.4% of the strains showing resistance to erythromycin. At least one of the virulence or toxin genes was detected in 61.1% of the strains, and seg was the most prevalent toxin gene, being detected in 44.4% of the strains. Full article

(This article belongs to the Special Issue Characterisation and Molecular Analysis of Staphylococcal Species: Their Impact on Colonization and Infection)

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19 pages, 2991 KiB

Open AccessArticle

Impact of Environmental Conditions on the Protein Content of Staphylococcus aureus and Its Derived Extracellular Vesicles

by Brenda Silva Rosa da Luz, Vinícius de Rezende Rodovalho, Aurélie Nicolas, Svetlana Chabelskaya, Julien Jardin, Valérie Briard-Bion, Yves Le Loir, Vasco Ariston de Carvalho Azevedo and Éric Guédon

Microorganisms 2022, 10(9), 1808; https://doi.org/10.3390/microorganisms10091808 - 09 Sep 2022

Cited by 2 | Viewed by 2016

Abstract

Staphylococcus aureus, a major opportunistic pathogen in humans, produces extracellular vesicles (EVs) that are involved in cellular communication, the delivery of virulence factors, and modulation of the host immune system response. However, to date, the impact of culture conditions on the physicochemical [...] Read more.

Staphylococcus aureus, a major opportunistic pathogen in humans, produces extracellular vesicles (EVs) that are involved in cellular communication, the delivery of virulence factors, and modulation of the host immune system response. However, to date, the impact of culture conditions on the physicochemical and functional properties of S. aureus EVs is still largely unexplored. Here, we use a proteomic approach to provide a complete protein characterization of S. aureus HG003, a NCTC8325 derivative strain and its derived EVs under four growth conditions: early- and late-stationary growth phases, and in the absence and presence of a sub-inhibitory concentration of vancomycin. The HG003 EV protein composition in terms of subcellular localization, COG and KEGG categories, as well as their relative abundance are modulated by the environment and differs from that of whole-cell (WC). Moreover, the environmental conditions that were tested had a more pronounced impact on the EV protein composition when compared to the WC, supporting the existence of mechanisms for the selective packing of EV cargo. This study provides the first general picture of the impact of different growth conditions in the proteome of S. aureus EVs and its producing-cells and paves the way for future studies to understand better S. aureus EV production, composition, and roles. Full article

(This article belongs to the Special Issue Characterisation and Molecular Analysis of Staphylococcal Species: Their Impact on Colonization and Infection)

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18 pages, 1140 KiB

Open AccessArticle

Trends in Occurrence and Phenotypic Resistance of Coagulase-Negative Staphylococci (CoNS) Found in Human Blood in the Northern Netherlands between 2013 and 2019

by Matthijs S. Berends, Christian F. Luz, Alewijn Ott, Gunnar I. Andriesse, Karsten Becker, Corinna Glasner and Alex W. Friedrich

Microorganisms 2022, 10(9), 1801; https://doi.org/10.3390/microorganisms10091801 - 07 Sep 2022

Cited by 3 | Viewed by 1663

Abstract

Background: For years, coagulase-negative staphylococci (CoNS) were not considered a cause of bloodstream infections (BSIs) and were often regarded as contamination. However, the association of CoNS with nosocomial infections is increasingly recognized. The identification of more than 40 different CoNS species has been [...] Read more.

Background: For years, coagulase-negative staphylococci (CoNS) were not considered a cause of bloodstream infections (BSIs) and were often regarded as contamination. However, the association of CoNS with nosocomial infections is increasingly recognized. The identification of more than 40 different CoNS species has been driven by the introduction of matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. Yet, treatment guidelines consider CoNS as a whole group, despite increasing antibiotic resistance (ABR) in CoNS. This retrospective study provides an in-depth data analysis of CoNS isolates found in human blood culture isolates between 2013 and 2019 in the entire region of the Northern Netherlands. Methods: In total, 10,796 patients were included that were hospitalized in one of the 15 hospitals in the region, leading to 14,992 CoNS isolates for (ABR) data analysis. CoNS accounted for 27.6% of all available 71,632 blood culture isolates. EUCAST Expert rules were applied to correct for errors in antibiotic test results. Results: A total of 27 different CoNS species were found. Major differences were observed in occurrence and ABR profiles. The top five species covered 97.1% of all included isolates: S. epidermidis, S. hominis, S. capitis, S. haemolyticus, and S. warneri. Regarding ABR, methicillin resistance was most frequently detected in S. haemolyticus (72%), S. cohnii (65%), and S. epidermidis (62%). S. epidermidis and S. haemolyticus showed 50–80% resistance to teicoplanin and macrolides while resistance to these agents remained lower than 10% in most other CoNS species. Conclusion: These differences are often neglected in national guideline development, prompting a focus on ‘ABR-safe’ agents such as glycopeptides. In conclusion, this multi-year, full-region approach to extensively assess the trends in both the occurrence and phenotypic resistance of CoNS species could be used for evaluating treatment policies and understanding more about these important but still too often neglected pathogens. Full article

(This article belongs to the Special Issue Characterisation and Molecular Analysis of Staphylococcal Species: Their Impact on Colonization and Infection)

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10 pages, 1416 KiB

Open AccessArticle

Changes in Amino Acid Metabolism of Staphylococcus aureus following Growth to the Stationary Phase under Adjusted Growth Conditions

by Mousa Alreshidi, Hugh Dunstan, Tim Roberts, Fevzi Bardakci, Riadh Badraoui, Mohd Adnan, Mohd Saeed, Fayez Alreshidi, Yazeed Albulaihed and Mejdi Snoussi

Microorganisms 2022, 10(8), 1503; https://doi.org/10.3390/microorganisms10081503 - 25 Jul 2022

Cited by 4 | Viewed by 1749

Abstract

The sharp increase in infections due to Staphylococcus aureus is associated with its ability to adapt to changes in its habitat. This study aimed to investigate the differences in the cytoplasmic amino acid profiles of a clinical strain of S. aureus under five [...] Read more.

The sharp increase in infections due to Staphylococcus aureus is associated with its ability to adapt to changes in its habitat. This study aimed to investigate the differences in the cytoplasmic amino acid profiles of a clinical strain of S. aureus under five combinations of stress-induced conditions representative of a wound site by varying temperature 35–37 °C, adding 0–5% NaCl and adjusting pH 6–8. The results indicated that aspartic acid, lysine, glutamic acid and histidine were the most abundant cytoplasmic amino acids in the control samples grown under optimal growth conditions. However, the magnitudes and levels of these amino acids were altered under the various wound site conditions, which led to differential cytoplasmic amino acid profiles as characterized by multivariate analyses (PLS-DA). The total cytoplasmic amino acid content was significantly reduced in the cells grown with 2.5% NaCl added at pH 7 and 37 °C relative to the control samples and other growth regimes. However, all combinations of enhanced stress conditions showed unique and characteristic changes in the concentration profiles of the cytoplasmic amino acids. These outcomes supported the hypothesis that bacterial cells of S. aureus maintain different metabolic homeostasis under various stress-induced conditions. The potent capability of S. aureus to constantly and rapidly acclimatize to variations within the environment may reflect the crucial feature supporting its virulence as an opportunistic pathogenic bacterium to invade the wound site. Understanding the control systems governing these marked changes in amino acids during the adaptation to the potential wound site conditions of this dangerous bacterium may offer new clinical controls to combat infection. Full article

(This article belongs to the Special Issue Characterisation and Molecular Analysis of Staphylococcal Species: Their Impact on Colonization and Infection)

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Review

Jump to: Research

20 pages, 2142 KiB

Open AccessReview

Bidirectional Functional Effects of Staphylococcus on Carcinogenesis

by Yuannan Wei, Esha Sandhu, Xi Yang, Jie Yang, Yuanyuan Ren and Xingjie Gao

Microorganisms 2022, 10(12), 2353; https://doi.org/10.3390/microorganisms10122353 - 28 Nov 2022

Cited by 6 | Viewed by 4611

Abstract

As a Gram-positive cocci existing in nature, Staphylococcus has a variety of species, such as Staphylococcus aureus and Staphylococcus epidermidis, etc. Growing evidence reveals that Staphylococcus is closely related to the occurrence and development of various cancers. On the one hand, cancer [...] Read more.

As a Gram-positive cocci existing in nature, Staphylococcus has a variety of species, such as Staphylococcus aureus and Staphylococcus epidermidis, etc. Growing evidence reveals that Staphylococcus is closely related to the occurrence and development of various cancers. On the one hand, cancer patients are more likely to suffer from bacterial infection and antibiotic-resistant strain infection compared to healthy controls. On the other hand, there exists an association between staphylococcal infection and carcinogenesis. Staphylococcus often plays a pathogenic role and evades the host immune system through surface adhesion molecules, α-hemolysin, PVL (Panton-Valentine leukocidin), SEs (staphylococcal enterotoxins), SpA (staphylococcal protein A), TSST-1 (Toxic shock syndrom toxin-1) and other factors. Staphylococcal nucleases (SNases) are extracellular nucleases that serve as genomic markers for Staphylococcus aureus. Interestingly, a human homologue of SNases, SND1 (staphylococcal nuclease and Tudor domain-containing 1), has been recognized as an oncoprotein. This review is the first to summarize the reported basic and clinical evidence on staphylococci and neoplasms. Investigations on the correlation between Staphylococcus and the occurrence, development, diagnosis and treatment of breast, skin, oral, colon and other cancers, are made from the perspectives of various virulence factors and SND1. Full article

(This article belongs to the Special Issue Characterisation and Molecular Analysis of Staphylococcal Species: Their Impact on Colonization and Infection)

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