A total of 148 E. coli strains displaying reduced susceptibility to ciprofloxacin (MIC > 2 g/ml) and causing uncomplicated urinary tract infections in eight European countries during 2003 to 2006 were studied. Their phylogenetic groups, biochemical profiles, and antibiotic susceptibilities were determined. Determination of the O:H serotype, pulsed-field gel electrophoresis (PFGE), randomly amplified polymorphic DNA (RAPD) PCR, and multilocus sequence typing provided additional discrimination. The majority (82.4%) of the microorganisms (122/148) carried resistance to two or more additional drugs, with the pattern ciprofloxacin-trimethoprim-sufamethoxazole-tetracycline-ampicillin being the most represented (73 strains out of 148; 49.3%). Extended-spectrum beta-lactamase production was detected in 12/148 strains (8.1%), with CTX-M-15 being the most-common enzyme. Six strains out of the whole collection studied (4.0%) contained a qnrB-like gene. Overall, 55 different PFGE or RAPD PCR profiles could be distinguished, indicating a substantial heterogeneity. However, about one-third (51/148) of the strains belonged to two clonal groups: O15:K52:H1 (phylogenetic group B2, lactose-nonfermenting variant, ciprofloxacin MIC of 16 g/ml) and O25:H4 sequence type 131 (ST-131) (phylogenetic group D, ciprofloxacin MIC of >32 g/ml). With the exception of Poland, strains of these two groups were isolated in samples from all participating countries but more frequently in samples from Spain and Italy. In some representative strains of the two main clonal groups, alterations in GyrA and ParC were the basic mechanism of fluoroquinolone resistance. In some members of the O25:H4 ST-131 group, displaying a ciprofloxacin MIC of >32 g/ml, additional OmpF loss or pump efflux overexpression was found. In the Mediterranean area, strains belonging to these two clonal groups played a major role in determining the high rate of fluoroquinolone-resistant E. coli strains observed in the community.Uncomplicated urinary tract infections (UTIs) are among the most prevalent infectious diseases mainly affecting women. Between one-quarter and one-half of all women experience a UTI at some time (27).The overall etiology has not changed in recent years, and Escherichia coli remains by far the most-common uropathogen, accounting for Ͼ80% of all positive cultures (19). However, the management of these infections is becoming complicated due to the emergence of resistance to several first-line antimicrobial agents in this primary pathogen (13).In fact, in E. coli bacteria, ampicillin and sulfamethoxazoletrimethoprim resistance rates have reached 20% to 50% worldwide. In Europe, increasing percentages of ciprofloxacinresistant mutants have been observed in the community in Spain, Portugal, and Italy (10,18).The results of a recent surveillance survey, the ARESC (Antimicrobial Resistance Epidemiological Survey on Cystitis) study, have shown high rates (Ͼ10%) of ciprofloxacin-resistant E. coli in Spain, Italy, and Russia and the emergence of this problem in all c...

Objectives: To investigate the first Italian outbreak of bloodstream infections caused by multidrugresistant (MDR) Klebsiella pneumoniae producing metallo-b-lactamase (MBL), which occurred in three wards of one large tertiary-care hospital in Genoa, Italy, from September 2004 to March 2005.Methods: MBL production was screened by an imipenem-EDTA disc synergy test and confirmed by a conventional hydrolysis test. Antibiotic susceptibility was determined by broth microdilution or disc diffusion. PFGE was used to study the genetic relatedness of isolates. PCR and sequencing were carried out to identify the b-lactamase genes and to analyse the genetic context of the MBL gene. Outer membrane protein (OMP) profiles were analysed by SDS-PAGE.Results: Nine cases of bloodstream infections caused by an MDR strain of K. pneumoniae producing the VIM-1 MBL and the SHV-5 extended-spectrum b-lactamase (ESBL) were identified. The isolates exhibited various carbapenem resistance levels (imipenem MICs ranged from 4 to 64 mg/L) and were resistant to other b-lactams, fluoroquinolones, trimethoprim/sulfamethoxazole and chloramphenicol. The isolate with the highest imipenem MIC also lacked the k36 OMP. The bla VIM-1 gene cassette was part of the variable region of a class 1 integron that also included an aac(6 0 )-IIc cassette. The ESBL and MBL genes were transferable by conjugation.Conclusions: This is the first report on the emergence of an MDR strain of K. pneumoniae producing the VIM-1 MBL, causing an outbreak of bloodstream infections in an Italian hospital. The strain evolved through OMP alterations generating a mutant with increased carbapenem resistance.

Aims:Endox ® Endodontic System (Endox) is used for endodontic treatment by a high frequency alternating current (HFAC). This device damaged the envelopes of spores and vegetative organisms. If the integrity of the envelope is compromised, the transit of compounds in the two directions is possible. This latter aspect was investigated here. Methods:The instrument delivered a 60ms pulse at a frequency 300 kHz, and power 800 KV/m. DNA transfer was verified using Escherichia coli K-12 strain carrying a non conjugative plasmid pBP517 (gyrA + ) as donor and a rifampicin and nalidixic acid resistant recipient. 0.2 ml of mixture of donor and recipient strains in saline was exposed to HFAC and plated on selective media. Uptake of antimicrobials and a delay in re-growth was assessed exposing the strains to HFAC.Results: Plasmid transfer was detected under different experimental conditions. From 9 to 27 recombinants were found. Representative recombinants cured from plasmid showed the original phenotype. HFAC promoted the uptake of ineffective antibiotics, and induces a 1 h of delay in re-growth on the strains. Conclusion:Endox exhibited an effect on microrganisms which is reminiscent with that occuring in electroporation, but with a mode of action that saved materials and time.

Some new features of the in vitro activity of ceftibuten, an oral third generation cephalosporin, have been studied in reference to respiratory and urinary tract pathogens included in its antibacterial spectrum. At 0.25XMIC (minimum inhibitory concentration) and 0.5XMIC levels, ceftibuten was able to affect the biofilm production in 2/3 of both Escherichia coli and Proteus mirabilis strains, and reduced the number of strains capable of adhering to epithelial cells by about 35% in comparison to the control. Surface hydrophobicity was also influenced by ceftibuten and the other drugs at 0.25-0.5XMIC. In general, no marked variation in the virulence traits of the pathogens studied were found by exposing bacteria to sub-MICs of ceftibuten. Plasmid loss (from 1.8 to 37.2%), and Flac transfer inhibition (about 30-50% reduction in the number of recombinants) were detected under the experimental conditions used. This study confirms the excellent antibacterial properties of ceftibuten by adding new information about the effects of this antibiotic against pathogens often involved in respiratory and urinary tract infections that may be treated with this compound, supporting the appropriate use of this cephalosporin.

Abstract:The virulence of C. albicans is associated with the transitional evolution from yeast to filamentous forms. We were interested in the effects amphotericin B (AMB), ketoconazole (KTC) and -radiations might have on these broadly defined phenotypes as determined by the CFU procedure. By using collagen gel as the 3-dimensional support of cell culture, diverse experimental conditions were contemplated in order to modulate the differentiation of Candida during sessile and planktonic growth. These conditions included the co-culture with human epithelial and endothelial cells and treatment with farnesol, tyrosol and conditioned medium from P. aeruginosa. The overall results were as follows: 1) The survival of Candida was inhibited by the exposure to -radiations, but only after the organism was induced to progress into excess filamentation, while in normal growth conditions it proved to be radioresistant; 2) AMB inhibited the growth of yeast forms, while KTC was specifically toxic to filamentous forms and 3) the combined treatment of filamentous Candida with KTC and -radiations resulted in the synergistic inhibition of the organism. These findings indicate that both the radiosensitivity of C. albicans and its response to the synergistic effects of -radiations and KTC are filamentation-dependent pharmacological processes.