The COMBACTE Consortium at ECCMID

This year COMBACTE will be present at ECCMID with different oral sessions and poster presentations, sharing the results and science from the COMBACTE consortium. In total COMBACTE will be represented with 9 abstracts (5 COMBACTE-NET, 3 COMBACTE-MAGNET & 1 COMBACTE-CARE). We asked the presenters from our consortium what they are going to present and why their research is so important in combatting antimicrobial resistance.

On Monday 25 April from 12:00 to 13:00, Qiang Lin will present his poster P0368. This abstract reveals the work of elucidating the evolution and pathogenicity of Staphylococcus aureus (S. Aureus) ST398 from human- and animal-sources based on genome-level and secretome-level analyses. Significance differences in resistance genes, plasmid types and virulence genes were found between animal-source and human-source ST398.

Based on prophage content, ST398 were further classified into 4 clades, and secretomes differed clearly among the clades on global level of proteins including virulence factors. The results reveal both genomic and proteomic sights into ST398, which improves the understanding of evolution and pathogenicity development of ST398.

This research is important in the combat on AMR according to Qiang Lin: “Since the first detection of S. aureus sequence type (ST) 398 in the early 2000s, ST398 widely spreads and causes various diseases for human and livestock. Some ST398 isolates are methicillin-resistant and show resistance to other antimicrobials, which heightens the difficulties to treat ST398-caused infection and seriously threatens human health.”

On Tuesday 26 April between 08:30 – 10:30, Maria will present her abstract in a short oral presentation . The abstract shows results from EURECA trial regarding how attributable mortality estimation from carbapenem-resistant Enterobacterales (CRE) infections may change according to confounding control.

For the purpose, 235 CRE-CSE pairs of patients (matched according to syndrome, type of adquisition, hospital ward and lenght of previous stay) were evaluated. Results suggest that, after controlling for different confounders, including adequate treatment and source control, CRE infections did not show a higher mortality compared to susceptible ones.

“In our opinion this is a very important finding, as until the date information available suggested that CRE infections had higher mortality rates, but it was not clear wheter this was because CRE microorganism expressed a higher virulence theirselves, or, as we conclude according to EURECA results, mortality was higher because CRE infections usually affect more fragile patients who normally receive suboptimal treatment. Efforts should emphasize on the development of new active molecules.” answers Maria on the Question why this research is so important in the combat against AMR

On Sunday 24 April between 12:00 to 13:00, Reinaldo Espindola will presents the results of one of the objectives of ARTHR-IS project, 128 cases of S. aureus prosthetic joint infection (SA-PJI) were identified in 6 European hospitals and followed for 18 months after the surgical procedure performed to treat SA-PJI. The trial aimed to calculate the rate of treatment failure and to define the variables associated with treatment failure.

In this study, important results were observed despite improvement in the management of these infections in recent years:

a considerable proportion of SA-PJIs failed after initial surgical treatments (overall treatment failure rate of 32.8%);
significant functional loss must be considered in addition to clinical failure, mainly in patients in whom the prosthesis was removed, with no possibility of recovery;
in patients manage with debridement, antibiotic and prosthesis retention (DAIR), the loss of function was lower even if this procedure fails;
the importance of some risk factors for treatment failure were reinforced, including the protective role of rifampicin-based treatment in DAIR, and some risk factors not described in previous studies (as anaemia and obesity) were identify.

“Prosthetic joint infections are one of the most complex infections that the clinicians must deal with and those caused by S. aureus one of the most frequent and with the highest failure rates.” says Reinaldo “The identification of the risk factors associated with failure can help to select the best procedure, avoiding unnecessary or excessive consumption of antibiotics and improving the patient’s functionality.“

Crossing Borders and Generating an International Network, Reinaldo Espindola 1

On Tuesday 26 April between 13:30 – 15:30, Leen Timbermont presents the poster on the molecular epidemiological study on S. aureus colonizing human nares in the European population undergoing surgery. A selection of S. aureus isolates (n=250) collected as part of ASPIRE-SSI in 2018-2019, were whole genome sequenced after which the genomic data was used to characterise the isolates in combination with phenotypic MRSA screening. The results show that S. aureus isolates circulating in Europe are still highly diverse with many different genomic backgrounds. ST45, ST30 and ST398 were found to be the most prevalent backgrounds in this study population. Moreover, MRSA levels and the coupled presence of antimicrobial resistance genes in the mainly MSSA community remain low.

“Since S. aureus colonization is a predisposing factor for infection, it is important to understand which clones are circulating in Europe.” says Leen when she indicates the importance of the research “Furthermore, with the increase in AMR, there is a need for alternative therapeutics. Whole genome sequencing can identify new potential therapeutic targets to combat the many different mechanisms that make S. aureus a potent infectious pathogen. Our study demonstrated differential carrier rates for potential anticolonization targets, some of which have already been investigated in this context. The fact that some of these antigens were not uniformly present in all isolates of our study collection raises the question of whether addressing these factors would be beneficial in eradicating or reducing the bacterial burden in surgical patients prior to surgery. Multicomponent vaccines are a possible solution to circumvent this.”

Check all our presentations at ECCMID here