Does the adoption of EUCAST susceptibility breakpoints affect the selection of antimicrobials to treat acute community-acquired respiratory tract infections?

Background: In several European Countries, by the end of 2012, CLSI guidelines will be replaced by EUCAST. We compared antimicrobial susceptibility results of a large number of respiratory pathogens using both EUCAST and previously adopted CLSI criteria to evaluate the impact on susceptibility patterns and the possible consequences that could occur in clinical practice due to this replacement.For S. pyogenes and S. aureus, the interpretation of susceptibility data using the EUCAST criteria did not produce relevant changes in comparison to CLSI.Against S. pneumoniae, more restrictive EUCAST breakpoints could lead to increased benzylpenicillin and/or amoxicillin-clavulanate resistance rates, which in turn could translate in increased dosages of these antibiotics or usage of alternative agents for respiratory tract infections.Against S. pneumoniae, M. catarrhalis and H. influenzae, cefuroxime-axetil and cefaclor produced the most divergent results depending on the breakpoints adopted and these striking differences could lead to the revision of those guidelines suggesting these two cephalosporins as alternatives in the management of upper respiratory tract infections.Discussion: Many differences exist between CLSI and EUCAST breakpoints. However, only in a few cases do these differences translate in major interpretive category discrepancies. In countries adopting more restrictive EUCAST breakpoints, clinicians should be aware of these discrepancies and that they could be faced with antibiotic-resistant respiratory pathogens more frequently than before.Summary: The interpretive discrepancies between EUCAST and CLSI suggest that the discussion on the management of community-acquired respiratory tract infections is still open and further studies are desirable to better define the role of some antibiotic

Local survelance study on etiology of community-and hospital-acquired urinary tract infections (UTI) and antimicrobial susceptibility of uropathogens

This study was conduced during October 2010-March 2011 with the collaboration of the microbiology laboratory of International Evangelical Hospital (Voltri division) to identify the most frequent pathogens isolates from Urinary Tract Infections (UTI) and to evaluate their antibiotics susceptibility patterns. Overall, 780 consecutive, non duplicate strains were collected and sent to the coordinating laboratory. 143 strains were from Healthcare settings and 637 from comunity acqueired infections.The most rappresented pathogens was E. coli. In our region the epidemiological community landscape in terms of resistance, is getting closer to the nosocomial setting

In vitro antimicrobial activity of tigecycline against Gram negative and Gram positive pathogens collected in Northen Italy (T.E.S.T. program 2010)

Background. In this study (part of the global T.E.S.T. program) was evaluated the in vitro activity of tigecycline, member of a new class of antimicrobial agents, the glycylcyclines, against clinical isolates collected in Italy. Methods. A total of 194 clinical isolates were collected and identified in our Institution during 2010. Minimum inhibitory concentrations (MICs) of the antimicrobial agents were determined by the CLSI (2010) recommended broth microdilution method. Results. Globally 129 Gram negative and 65 Gram positive pathogens were evaluated.Tigecycline demonstrated excellent inhibitory activity against Escherichia coli, Haemophylus influenzae, Enterococcus spp., Staphylococcus aureus MetS, Streptococcus pneumoniae and Streptococcus agalactiae with MIC90 1mg/l. Conclusion. Tigecycline exhibited potent in vitro antibacterial activity (comparable to or greater than most commonly employed antimicrobials) against both Gram positive and negative clinical pathogens. These data suggest that tigecycline, with an expanded broad-spectrum antimicrobial activity, may be an effective empiric therapeutic option for the treatment of serious infections caused by clinically relevant pathogens

Epidemiology of skin and soft tissue pathogens circulating in Liguria in 2011

This study was conduced during March-May 2011 with the collaboration of 4 clinical microbiology laboratories evenly distibuited across the Ligurian area to identify the most frequent pahogens isolates from skin and soft tissue infections and to evaluate their antibiotic susceptibility patterns. Overall, 213 consecutive, non duplicate strains were collected and sent to the coordinating laboratory.The most rappresented pathogens were: S. aureus (35.7%), P. aeruginosa (14%), E. coli (12.7%), Staphylococcus coaugulase negative (6.6%) and Enterococcus spp. (4.7%). The data indicate an increase of Gram negative compared to previous years, S. aureus remains the most common pathogen.The methicillin resistance in S. aureus was 43.4% and no one Enterococcus spp. resistant to vancomicin was found

Epidemiological study of pathogens isolated from blood in Liguria during 2011

Objectives. An epidemiological study addressed to identify the most represented pathogens isolated from blood and to evaluate their antibiotic susceptibility patterns, was conducted. Methods. Five clinical microbiology laboratories, homogenously distributed in Liguria, were required to collected all consecutive non-duplicates strains isolated from blood cultures during March 2011 to May 2011. the strains were sent to the reference laboratory (Section of Microbiology, DISC, University of Genoa, Italy). Results. A total of 159 microorganisms were enrolled, including 81 Gram positive, 69 Gram negative and 9 fungi.The most represented pathogens were: Escherichia coli (35), Staphylococcus aureus (26), S. epidermidis (20), S. hominis (10). Samples were collected mainly from medicine (59 isolates).Among the staphylococci, the most active molecules were: vancomycin (100% of susceptible strains), teicoplanin (93.4%), trimethoprim-sulfamethoxazole (83.8%) and tobramycin (61.6%). Enterococci showed rates of resistance to vancomycin of 25%. Enterobacteriaceae exhibited resistance to ampicillin (76.9%), ceftriaxone (44.4%), ciprofloxacin (43.3%), trimethoprim-sulfamethoxazole (36.6%) and ceftazidime (32.2%). Conclusions. The data show a higher incidence of Gram positive (51%) in comparison to Gram negative (43.4%). Gram-positive strains showed a high resistance level to fluoroquinolones (92.3%) while Gram-negative resulted resistant to ceftriaxone (44.4%) and fluoroquinolone (43.3%)

Epidemiological study of pathogens isolated from blood in Liguria (January-April 2010)

Objectives. An epidemiological study to identify the most represented pathogens isolated from blood and to evaluate their antibiotic susceptibility patterns, was conducted. Methods. Seven clinical microbiology laboratories, homogeneously distributed in the Ligurian area,were required to collected all consecutive non-duplicates strains isolated froom blood cultures during January 2010 to April 2010. The strains were sent to the reference laboratory (Sezione di Microbiologia del DISC, University of Genoa, Italy). Results. A total of 277 microorganisms were enrolled, including 155 Gram positive and 122 Gram negative.The most represented pathogens were: Escherichia coli (68), Staphylococcus aureus (57), Staphylococcus epidermidis (32), Staphylococcus hominis (17), Pseudomonas aeruginosa (15), Klebsiella pneumoniae (15), Enterococcus faecalis (11). Samples were collected mainly from medicine (66, 33.3%, of this number was determined by E. coli), intensive care units (33, 18.2% of this number consisted of S. epidermidis), surgery (24, 33.3% consisted of E. coli) and infectious diseases (20, of which S. aureus, E. coli and S. epidermidis equally represented 20.0%).Among the Staphylococci the most active molecules were: vancomycin and teicoplanin (100% of susceptible strains), chloramphenicol (92.3%) and trimethoprim-sulfamethoxazole (89.8%). Among the OXA-R Staphylococci (81/123, 65.9%) the most active molecules were: vancomycin and teicoplanin (100% of susceptible strains), chloramphenicol (93.8%) and trimethoprim-sulfamethoxazole (84.8%). Enterococci showed rates of resistance to vancomycin of 5.9%. Enterobacteriaceae exhibited resistance to ampicillin (77.5%), trimethoprim-sulfamethoxazole (42.6%), ciprofloxacin (41.2%), ceftriaxone (37.5%), ceftazidime (28.2%), cefepime (26.7%), cefoxitin (22.1%), piperacillintazobactam (20.4%), imipenem (4.7%) and amikacin (2.9%). The Gram negative non-Enterobacteriaceae showed rates of resistance of 100% to ceftriaxone, 81.3% to trimethoprim-sulfamethoxazole, 42.1% to ciprofloxacin and piperacillin-tazobactam, 33.3% to ceftazidime, 31.6% to cefepime, 27.8% to imipenem, 26.3 % to amikacin. Conclusions. The data show a higher incidence of Gram positive (56%) in comparison to Gram negative (44%).This confirms the high incidence of oxacillino-resistance in Staphylococci in our geographic area.Against Enterobacteriaceae rates of resistance were observed in excess of 20% for all drugs tested except imipenem (4.7%) and amikacin (2.9%). The proportion of imipenem-resistant isolates was constituted of strains of K. pneumoniae carbapenemase producers

Modelling of finger-surface contact dynamics

The tactile perception of a surface texture originates from the scanning of a finger on the surface. This kind of sliding contact activates the mechanoreceptors located into the skin, allowing the brain to identify the object and to perceive information about the scanned surface. In this paper, a numerical model describing finger-surface scanning is introduced in order to investigate the relationship between contact induced vibrations and scanning conditions. The model takes into account finger and surface shapes, material properties, normal contact force, and scanning velocity. Model validation is provided by comparison with experimental tests. Afterwards, the model is applied to clarify the role played by contact/scanning parameters on the induced vibration. The proposed model is useful to develop a comprehensive parametrical analysis of the vibration induced in finger-surface scanning, and to investigate the influence of material and contact properties on tactile perception

A model for vibration-mediated tactile perception

Tactile perception originates from scanning the fingertip on object surfaces: in this condition, pressure and/or interaction between fingertip and surface ridges induce stresses and vibrations in the mechanoreceptors located in the skin, allowing the brain to identify objects and to perceive information about the surfaces [1-3]. In addition, many experimental investigations have shown that low wavelength surface patterns (with the respect to the fingerprint spatial period) are perceived by pressure, while high wavelength patterns are sensed by means of vibrations (duplex perception mechanism). In the present work, a numerical model describing finger-surface scanning is introduced. The model takes into account finger and surface shapes, material properties, normal contact force, and scanning velocity. The proposed model describes the vibration induced by a sliding contact between two sinusoidal surfaces, and it is capable to explain the duplex perception mechanism on a mathematical basis. Validation has been fulfilled by comparison with experimental results present in the literature; a parametrical investigation is performed in non-dimensional formulation in order to clarify the role played by contact/scanning parameters on the induced vibration, and to investigate the influence of material and contact properties on tactile perception