Quinolone-and fluoroquinolone-resistant Escherichia coli strains harbor fewer virulence factors than susceptible strains. The reasons underlying this correlation are incompletely understood. We investigated the phylogenetic background, the presence of the papC, hlyA, and cnf1 (pathogenicity island II J96 -associated), fimA, iss, and iutA genes, and the presence of type 1 fimbriae, P fimbriae, and hemolysin in 243 urinary E. coli isolates resistant only to quinolones (8%), resistant to both quinolones and fluoroquinolones (51%), or susceptible to both drugs (41%). Group B2 accounted for 56% of the isolates, showing a significantly higher prevalence among fluoroquinolone-susceptible strains than among resistant strains (65% versus 50% [P ‫؍‬ 0.03]). hly and cnf1 were significantly more associated with susceptibility (P < 0.001) and with group B2 (P < 0.001 for group B2 versus groups A and D). However, within group B2, fluoroquinolone-resistant strains showed lower prevalences of papC, hlyA, and cnf1 than their susceptible counterparts (P < 0.001). In contrast, the incidence of iutA appeared higher for refractory isolates, including group B2, than for susceptible isolates (P < 0.001). Only in group B2 did fluoroquinolone-resistant strains reveal a lesser ability to agglutinate Saccharomyces cerevisiae (7%) than quinolone-resistant (87%) and susceptible (80%) isolates, despite uniform possession of fimA genes. No similar contrast emerged for expression of hemolysin and P fimbriae. Mutations conferring quinolone and fluoroquinolone resistance may thus require a particular genetic background, not strictly correlated with phylogenetic groups. More interestingly, the mutational event itself can affect the expression of type 1 fimbriae, at least in the prevalent and complex B2 strains.Urinary tract infections (UTIs) in humans are the most frequent bacterial disease, affecting both inpatients and outpatients. Especially the uncomplicated cases are mainly due to extraintestinal pathogenic Escherichia coli (ExPEC) (39). In recent years, management of UTIs has become increasingly problematic due to the emergence of resistance to first-line antibiotics among the causative bacteria, particularly among uropathogenic E. coli (UPEC) strains. This phenomenon involves quinolones (Q) and fluoroquinolones (FQ) (25), drugs of paramount importance in the treatment of several other infectious diseases. Indeed, the renal excretion of these molecules and the availability of oral and parenteral formulations have allowed them to compete with aminoglycosides and betalactams in the therapy of complicated UTIs, especially in the hospital setting. Their appropriate spectrum and good tolerability have also led to increased empirical adoption in uncomplicated infections, although their usage for these conditions in outpatients is still under debate.In E. coli, as in other gram-negative bacteria, DNA gyrase, which codifies type II DNA topoisomerases, is the main target of Q and FQ, and mutation in gyrA is the most common way to acquire resistance....

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Recently developed automated discontinuous flow centrifuge (DFC) separators can produce leuko- and erythrocyte-poor platelet concentrates (PC). According to general experience with these machines it is difficult to obtain more than 4 X 10(11) platelets, though a second program set up by Coffe et al. appears to produce PC containing approximately 5 X 10(11) platelets suspended in a plasma volume of 390 ml. At our center we employed a new Dideco cell separator equipped with the surge pump and a technique developed for the production of small volume, RBC and WBC-very poor PC. In 60 routine procedures we obtained the following results: mean processing time 87 +/- 11 minutes; final volume of PC 136 +/- 19 ml, with a mean platelet yield of 5.21 X 10(11) platelets. WBC contamination was 1.8 X 10(8) (93% lymphocytes) and RBC were 3.1 X 10(8). Plasma volume as well as WBC and RBC contamination were reduced by recirculating PC after the 6th pass. The demand for single donor platelet concentrates (PC) is increasing progressively. Recently developed automated cell separators can produce leukocyte (WBC) and erythrocyte (RBC) poor PC. With these machines it may be difficult to obtain PC containing at least 4 X 10(11) platelets and less than 1 X 10(9) leukocytes (1, 2, 3) since donor variables such as hematocrit, precounts, buffy coat formation and initial plasma light transmission are of paramount importance for the efficiency of the program. At our center a prototype discontinuous flow centrifuge (DFC) cell separator equipped with the surge pump was studied.(ABSTRACT TRUNCATED AT 250 WORDS)