Publications by authors named "Lorenzo Mattia Lazzaro"

4 Publications

  • Page 1 of 1

Staphylococcus aureus ST228 and ST239 as models for expression studies of diverse markers during osteoblast infection and persistence.

Microbiologyopen 2021 Mar;10(2):e1178

Department of Biomedical and Biotechnological Sciences (BIOMETEC), Medical Molecular Microbiology and Antibiotic Resistance laboratory (MMARLab, University of Catania, Catania, Italy.

The ability of S. aureus to infect bone and osteoblasts is correlated with its incredible virulence armamentarium that can mediate the invasion/internalization process, cytotoxicity, membrane damage, and intracellular persistence. We comparatively analyzed the interaction, persistence, and modulation of expression of selected genes and cell viability in an ex vivo model using human MG-63 osteoblasts of two previously studied and well-characterized S. aureus clinical strains belonging to the ST239-SCCmecIII-t037 and ST228-SCCmecI-t041 clones at 3 h and 24 h post-infection (p.i). S. aureus ATCC12598 ST30-t076 was used as a control strain. Using imaging flow cytometry (IFC), we found that these strains invaded and persisted in MG-63 osteoblasts to different extents. The invasion was evaluated at 3 h p.i and persistence at 24 h p.i., in particular: ATCC12598 internalized in 70% and persisted in 50% of MG-63 cells; ST239-SCCmecIII internalized in 50% and persisted in 45% of MG-63 cells; and ST228-SCCmecI internalized in 30% and persisted in 20% of MG-63 cells. During the infection period, ST239-III exerted significant cytotoxic activity resulting from overexpression of hla and psmA and increased expression of the genes involved in adhesion, probably due to the release and re-entry of bacteria inside MG-63 cells at 24 h p.i. The lower invasiveness of ST228-I was also associated with non-cytotoxic activity inside osteoblasts. This clone was unable to activate sufficient cellular reaction and succumbed inside MG-63 cells. Our findings support the idea of considering new strategies, based on a translational approach-eukaryotic host-pathogen interaction (EHPI)-and to be applied on a large scale, to predict S. aureus /osteoblast interaction and treat bone infections. Such strategies rely on the study of the genetic and biochemical basis of both pathogen and host.
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http://dx.doi.org/10.1002/mbo3.1178DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8087985PMC
March 2021

Internalization in Osteoblast Cells: Mechanisms, Interactions and Biochemical Processes. What Did We Learn from Experimental Models?

Pathogens 2021 Feb 19;10(2). Epub 2021 Feb 19.

Medical Molecular Microbiology and Antibiotic Resistance Laboratory (MMARLab), Department of Biomedical and Biotechnological Sciences (BIOMETEC), University of Catania, 95125 Catania, Italy.

Bacterial internalization is a strategy that non-intracellular microorganisms use to escape the host immune system and survive inside the human body. Among bacterial species, showed the ability to interact with and infect osteoblasts, causing osteomyelitis as well as bone and joint infection, while also becoming increasingly resistant to antibiotic therapy and a reservoir of bacteria that can make the infection difficult to cure. Despite being a serious issue in orthopedic surgery, little is known about the mechanisms that allow bacteria to enter and survive inside the osteoblasts, due to the lack of consistent experimental models. In this review, we describe the current knowledge about internalization mechanisms and various aspects of the interaction between bacteria and osteoblasts (e.g., best experimental conditions, bacteria-induced damages and immune system response), focusing on studies performed using the MG-63 osteoblastic cell line, the best traditional (2D) model for the study of this phenomenon to date. At the same time, as it has been widely demonstrated that 2D culture systems are not completely indicative of the dynamic environment in vivo, and more recent 3D models-representative of bone infection-have also been investigated.
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http://dx.doi.org/10.3390/pathogens10020239DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7922271PMC
February 2021

In Vitro Activity of Dalbavancin against Refractory Multidrug-Resistant (MDR) Isolates.

Antibiotics (Basel) 2020 Dec 3;9(12). Epub 2020 Dec 3.

Department of Biomedical and Biotechnological Sciences (BIOMETEC)-Medical Molecular Microbiology and Antibiotic Resistance Laboratory (MMARLab), University of Catania, 95123 Catania, Italy.

The high prevalence of methicillin-resistant (MRSA) infections, always treated with vancomycin and daptomycin, has led to the emergence of vancomycin-intermediate (VISA), heteroresistant vancomycin-intermediate (hVISA) and daptomycin non-susceptible (DNS) . Even if glycopeptides and daptomycin remain the keystone for treatment of resistant , the need for alternative therapies that target MRSA has now become imperative. The in vitro antibacterial and bactericidal activity of dalbavancin was evaluated against clinically relevant showing raised antibiotic resistance levels, from methicillin-susceptible to Multidrug-Resistant (MDR) MRSA, including hVISA, DNS and rifampicin-resistant (RIF-R) strains. A total of 124 strains were tested for dalbavancin susceptibility, by the broth microdilution method. Two VISA and 2 hVISA reference strains, as well as a vancomycin-resistant (VRSA) reference strain and a methicillin-susceptible (MSSA) reference strain, were included as controls. Time-kill curves were assayed to assess bactericidal activity. Dalbavancin demonstrated excellent in vitro antibacterial and bactericidal activity against all resistance classes, including hVISA and DNS isolates. The RIF-R strains showed the highest percentage of isolates with non-susceptibility, reflecting the correlation between B mutations and VISA/hVISA emergence. Our observations suggest that dalbavancin can be considered as an effective alternative for the management of severe MRSA infections also sustained by refractory phenotypes.
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http://dx.doi.org/10.3390/antibiotics9120865DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7761838PMC
December 2020

Detection of methicillin-resistant Staphylococcus aureus persistence in osteoblasts using imaging flow cytometry.

Microbiologyopen 2020 05 1;9(5):e1017. Epub 2020 Apr 1.

Department of Biomedical and Biotechnological Sciences (BIOMETEC), Medical Molecular Microbiology and Antibiotic Resistance Laboratory (MMARLab), University of Catania, Catania, Italy.

Methicillin-resistant S. aureus has been reported as the main pathogen involved in chronic infections, osteomyelitis, and prosthetic joint infections. The host/pathogen interaction is dynamic and requires several changes to promote bacterial survival. Here, we focused on the internalization and persistence behavior of well-characterized Staphylococcus aureus invasive strains belonging to the main ST-MRSA-SCCmec clones. To overcome the limitations of the cell culture method, we comparatively analyzed the ability of internalization within human MG-63 osteoblasts with imaging flow cytometry (IFC). After evaluation by cell culture assay, the MRSA clones in the study were all able to readily internalize at 3h postinfection, the persistence of intracellular bacteria was evaluated at 24h both by routine cell culture and IFC assay, after vancomycin-BODIPY staining. A statistical difference of persistence was found in ST5-SCCmecII (26.59%), ST228-SCCmecI (20.25%), ST8-SCCmecIV (19.52%), ST239-SCCmecIII (47.82%), and ST22-SCCmecIVh (50.55%) showing the same ability to internalize as ATCC12598 (51%), the invasive isolate used as control strain for invasion and persistence assays. We demonstrated that the intracellular persistence process depends on the total number of infected cells. Comparing our data obtained by IFC with those of the cell culture assay, we obtained greater reproducibility rates and a number of intracellular bacteria, with the advantage of analyzing live host cells. Moreover, with some limitations related to the lack of whole-genome sequencing analysis, we validated the different proclivities to persist in the main Italian HA-MRSA invasive isolates and our results highlighted the heterogeneity of the different clones to persist during cell infection.
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http://dx.doi.org/10.1002/mbo3.1017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7221431PMC
May 2020