Universitą degli studi di Pavia
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Caltagirone research activity
Study of pathogenicity, resistance mechanisms and clinical impact of emergent Gram-negative pathogens: Klebsiella pneumonia and Acinetobacter baumannii
The current emergence of carbapenemase-producing Gram-negatives is of concern because it is often associated to the occurrence of multidrug-resistant isolates for which very few (if any) antibiotic options remain available. This is the reason why detection and early recognition of carbapenemase producers are important. This is not always easy taking into account that those resistance determinants may sometimes confer only a slight increase of MIC values for carbapenems, and this is the reason why using molecular approaches and not only phenotypic tests are sometimes very helpful.
Among the current threats related to carbapenemase spread, metallo-β-lactamases (MBLs) of the IMP and VIM types and serine-β-lactamases of the OXA- and KPC-types relevant also in Italy because of the presence among both many different enterobacterial species and Pseudomonas aeruginosa and Acinetobacter baumannii.
The increase in multidrug-resistance of Gram-negative bacteria is mainly due to the presence/exchange of mobile genes on plasmids and integrons that may rapidly spread inter- and intra species.
Furthermore the rapid spread of multi-drug-resistant strains (clones) with virulence, ability to survive and to form biofilms enhanced features are often cause of nosocomial outbreaks and increases mortality rates within high risk wards.
Aim of the research:
− Identify using phenotypic and molecular methods the incidence of MDR isolates (National prevalence).
− Characterize plasmids/trasposons/clones responsible for the circulation of the resistance determinants.
− Correctly verify the susceptibility to antibiotics useful as therapeutic options(ex. colistin, tigicycline, fosfomycin and gentamicin) and determine the possible synergistic effects.
− Investigate bacterial virulence/host predisposing factors promoting the emergence of infections by MDR strains, with serious consequences on patient’s outcome.
The current emergence of carbapenemase-producing Gram-negatives is of concern because it is often associated to the occurrence of multidrug-resistant isolates for which very few (if any) antibiotic options remain available. This is the reason why detection and early recognition of carbapenemase producers are important. This is not always easy taking into account that those resistance determinants may sometimes confer only a slight increase of MIC values for carbapenems, and this is the reason why using molecular approaches and not only phenotypic tests are sometimes very helpful.
Among the current threats related to carbapenemase spread, metallo-β-lactamases (MBLs) of the IMP and VIM types and serine-β-lactamases of the OXA- and KPC-types relevant also in Italy because of the presence among both many different enterobacterial species and Pseudomonas aeruginosa and Acinetobacter baumannii.
The increase in multidrug-resistance of Gram-negative bacteria is mainly due to the presence/exchange of mobile genes on plasmids and integrons that may rapidly spread inter- and intra species.
Furthermore the rapid spread of multi-drug-resistant strains (clones) with virulence, ability to survive and to form biofilms enhanced features are often cause of nosocomial outbreaks and increases mortality rates within high risk wards.
Aim of the research:
− Identify using phenotypic and molecular methods the incidence of MDR isolates (National prevalence).
− Characterize plasmids/trasposons/clones responsible for the circulation of the resistance determinants.
− Correctly verify the susceptibility to antibiotics useful as therapeutic options(ex. colistin, tigicycline, fosfomycin and gentamicin) and determine the possible synergistic effects.
− Investigate bacterial virulence/host predisposing factors promoting the emergence of infections by MDR strains, with serious consequences on patient’s outcome.
