[Clinical and molecular characterization of ESBL-producing enterobacteria isolated from bacteremia in a university hospital].

Introduction: Extended-spectrum-β-lactamases (ESBL) are plasmid-encoded enzymes that confer resistance to multiple antimicrobials. ESBL-producing enterobacteria that cause bacteremia limit therapeutic options and increase mortality.

Objective: To perform a clinical and molecular description of bacteremia caused by ESBL-producing enterobacteria.

[Antimicrobial susceptibility, capsular serotypes and clonal relationship of invasive streptococcus pneumoniae isolates in adult population of the Bio-Bio region, Chile. 2005-2006].

Streptococcus pneumoniae infections constitute a public health problem. In our country there is scarce information regarding isolates from bacteraemic episodes in adult population. The antibiotic susceptibility, serotypes and clonal relationship of 56 isolates of S.

[Presence of metallo beta-lactamases in imipenem-resistant Pseudomonas aeruginosa].

Background: Metallo-beta-lactamases (MBL) confer high resistance to carbapenems in Pseudomonas aeruginosa (Psae). They are encoded in mobile elements of different genes (VIM, IMP, SMP, GIM), along with other resistance genes.

Aim: To detect the presence of MBL in imipenem resistant Psae strains.

[Mutations in gyrA and gyrB genes among strains of Gram-negative bacilli isolated from Chilean hospitals and their relation with resistance to fluoroquinolones].

Background: A progressive frequency of resistance to fluoroquinolones is observed among Gram-negative bacilli.

Aim: To investigate the mechanism of resistance to fluoroquinolones mediated by mutations affecting gyrA and gyrB genes in strains of Gram negative bacüli isolated from CMean hospitals.

Material And Method: Minimal inhibitory concentration of fluoroquinolones was determined in 91 randomly selected nalidixic acid-resistant strains of Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii and Pseudomonas aeruginosa, isolated from hospitals of 12 Chilean cities.

[Extended spectrum beta lactamases (ESBL) production in Acinetobacter baumannii strains isolated from Chilean hospitals belonging to VIII Region].

The resistance of Acinetobacter baumannii to ss-lactam antibiotics is mainly due to the synthesis of ss-lactamases. From a clinical point of view, this bacteria and others, grouped under the acronym SPACE (S: Serratia, P: Pseudomonas, A: Acinetobacter, C: Citrobacter, E: Enterobacter) are essentially Amp-C ss-lactamases producers. There is no local information about ESBL presence in Acinetobacter.

[Transference of extended-spectrum beta-lactamases from nosocomial strains of Klebsiella pneumoniae to other species of Enterobacteriaceae].

Background: Klebsiella pneumoniae is an important pathogenic bacterium, frequently isolated from nosocomial samples, that exhibits wide antimicrobial resistance profiles, including third generation cephalosporins (3GC), aminoglycosides and quinolones. The resistance to 3GC is mainly due to the synthesis of extended spectrum beta lactamases (ESBL), encoded by conjugative plasmids.

Aim: To investigate the potential transference of resistance to 3GC from nosocomial strains of K.