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....
SUMMARY: The application of statistical models on a time series of data arising from the MEDITS International Trawl Survey, an experimental demersal resources survey carried out during six years (1994)(1995)(1996)(1997)(1998)(1999) in the same season of the year (late spring -early summer) using the same fishing gear in a large part of the Mediterranean, has allowed for a study to compare, for the first time, the space-time distribution, abundance, and size structure of the two Aristeids Aristaeomorpha foliacea and Aristeus antennatus throughout most of the Mediterranean Sea. This research has shown a large variability among the six reference areas, that were arbitrarily defined within the basin. In particular the two shrimps do not seem to present any correlation or yield continuity in the years. The same lack of homogeneity was also observed in the time trend of the abundances and frequencies of each of the two species. These data seem to confirm the intrinsic variability of the species, the cause of which is still unknown and undocumented. Nevertheless, a longitudinal gradient of catches has been observed where A. antennatus is more abundant in the west and A. foliacea in the east of the basin.
Summary 1. The development of ecosystem approaches to environmental management implies the need to account for multiple pressures on ecosystems. Trends in multiple metrics that respond differently to changes in major environmental pressures need to be combined to evaluate the impacts of fishing and environmental changes on fish communities. 2. An exploited fish community is viewed as a three‐level food chain in which the two upper levels, or functional groups, are targeted by fishing fleets, while the lowest level is subject to environmental variation. Qualitative modelling is used to predict changes at the two upper levels, that is, top‐down vs. bottom‐up perturbations. Abundance and length metrics are calculated from survey data for 14 Mediterranean and East‐Atlantic groundfish shelf communities at both population and functional group levels. The joint likelihood of time trends in metrics is used to evaluate the evidence for different causes of changes. 3. A wide diversity of impacts is found to have equal evidence at the population level within each community. Consistency between the impacts identified and changes in pressures known from independent information is found at the functional group and community level. The results suggest that there is some compensation between species within functional groups. 4. Synthesis and applications. The method can be used to conduct an integrated assessment of community dynamics subject to multiple pressures. Joint trends in metrics provide evidence of which known pressures are having an impact on the community, and thus, which management actions should be taken to mitigate these changes.
Since the early 1990s, Loligo forbesi has apparently disappeared from much of the southern part of its former range, with catches off the Iberian Peninsula, for example, declining dramatically during the 1990s. The present paper assembles data from fishery and research cruise databases to examine the evidence for a shift in distribution, examine the relationship between abundance of this species and that of the partially sympatric Loligo vulgaris, and identify possible environmental correlates. Time-series of abundance of L. forbesi and L. vulgaris were assembled using fishery and survey data from Scotland, France, and Portugal. Based on availability of data and timing of the main fishery, data for autumn (October-December) were selected. Nine squid series and two explanatory variables (October sea surface temperature and the winter NAO index) were analysed using dynamic factor analysis (DFA). The optimal DFA model contained two common trends and both of the explanatory variables. The first common trend shows an increase from 1987 to 1999, and a slight decrease after 2000 onwards, and is positively related to L. forbesi abundance in the north of its range (Scotland), while negatively related to squid abundance (both species) in the south of their ranges (France and Portugal). The second trend identifies an increase from 1990 to 1995, followed by a decrease until 2002, and is positively related to the squid (L. forbesi and L. vulgaris) abundance series from French surveys and fisheries. The SST series was significantly related to three squid abundance series: positively with abundance of small L. forbesi in French surveys and negatively with the abundance of small L. forbesi from Scottish surveys and abundance of L. vulgaris in Portuguese surveys. The winter NAO series was significantly related to the abundance of small L. forbesi from Scottish surveys. The increase in SST after 1993 and subsequent high level may thus be associated with the decrease of Loligo abundance in the south area (France and Portugal) and the increase in Loligo abundance in the north area (Scotland).
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