SUMMARY In the last 10 years, extended-spectrum β-lactamase-producing enterobacteria (ESBL-E) have become one of the main challenges for antibiotic treatment of enterobacterial infections, largely because of the current CTX-M enzyme pandemic. However, most studies have focused on hospitalized patients, though today it appears that the community is strongly affected as well. We therefore decided to devote our investigation to trends in ESBL-E fecal carriage rates and comprehensively reviewed data from studies conducted on healthy populations in various parts of the world. We show that (i) community ESBL-E fecal carriage, which was unknown before the turn of the millennium, has since increased significantly everywhere, with developing countries being the most affected; (ii) intercontinental travel may have emphasized and globalized the issue; and (iii) CTX-M enzymes, especially CTX-M-15, are the dominant type of ESBL. Altogether, these results suggest that CTX-M carriage is evolving toward a global pandemic but is still insufficiently described. Only a better knowledge of its dynamics and biology will lead to further development of appropriate control measures.

Programme Hospitalier Recherche Clinique, Institut Pasteur, Inserm, French Public Health Agency.

We performed a prospective, international, observational study of 844 hospitalized patients with blood cultures positive for Streptococcus pneumoniae. Fifteen percent of isolates had in vitro intermediate susceptibility to penicillin (minimum inhibitory concentration [MIC], 0.12-1 microg/mL), and 9.6% of isolates were resistant (MIC, >or=2 microg/mL). Age, severity of illness, and underlying disease with immunosuppression were significantly associated with mortality; penicillin resistance was not a risk factor for mortality. The impact of concordant antibiotic therapy (i.e., receipt of a single antibiotic with in vitro activity against S. pneumoniae) versus discordant therapy (inactive in vitro) on mortality was assessed at 14 days. Discordant therapy with penicillins, cefotaxime, and ceftriaxone (but not cefuroxime) did not result in a higher mortality rate. Similarly, time required for defervescence and frequency of suppurative complications were not associated with concordance of beta-lactam antibiotic therapy. beta-Lactam antibiotics should still be useful for treatment of pneumococcal infections that do not involve cerebrospinal fluid, regardless of in vitro susceptibility, as determined by current NCCLS breakpoints.

Pig farming is a risk factor for increased nasal Staphylococcus aureus colonization. Using sequence typing and phylogenetic comparisons, we showed that overcolonization of farmers was caused by a few bacterial strains that were not present in nonfarmers but often caused swine infections. This finding suggests a high rate of strain exchange between pigs and farmers.

Retrospective studies have suggested that combination antibiotic therapy for severe bacteremic pneumococcal pneumonia may reduce mortality. We assessed this issue in a prospective, multicenter, international observational study of 844 adult patients with bacteremia due to Streptococcus pneumoniae. The effect of combination antibiotic therapy versus monotherapy on mortality was examined by univariate analyses and by logistic regression models. The 14-day mortality was not significantly different for the two groups. However, among critically ill patients, combination antibiotic therapy was associated with lower 14-day mortality (23.4 versus 55.3%, p = 0.0015). This improvement in survival was independent of country of origin, intensive care unit support, class of antibiotics, or in vitro activity of the antibiotics prescribed. Combination antibiotic therapy improved survival among critically ill patients with bacteremic pneumococcal illness.

NCT01526187.

The study of several Escherichia coli intestinal commensal isolates per individual in 265 healthy human subjects belonging to seven populations distributed worldwide showed that the E. coli population is highly structured, with major differences between the tropical and temperate populations.Escherichia coli is a commensal inhabitant of the intestinal tracts of healthy humans and many animal species, but it can also cause a wide range of diseases, ranging from diarrhea to extraintestinal infections (8). As it has been proposed that pathogenic E. coli strains are derived from commensal strains by the acquisition of chromosomal or extrachromosomal virulence operons (19), identifying the factors that shape the genetic structure of commensal strains might help us understand the emergence of virulence. E. coli can be considered to have a clonal genetic structure with a low level of recombination (7, 10). Four main phylogenetic groups, A, B1, B2, and D, constitute the bulk of the species (15). A few authors have examined commensal strains from humans (3-5, 13) using population genetics molecular tools (for a pioneer review, see reference 14). A significant locale-specific distribution among groups A, B1, B2, and D has been observed in human commensal strains in three geographically distinct human populations (French, Croatian, and Malian) (9).To gain insight into the composition of the E. coli human commensal microbiota, we characterized the relative abundance of E. coli phylogenetic groups in a large collection of 1,740 isolates from 265 subjects belonging to seven populations spread over three continents and compared the results to those of previous studies using the same approach.Bacterial isolates. Isolates were collected between 1999 and 2001 from seven human populations composed of healthy adult subjects of both sexes from 15 to 65 years of age, except when otherwise stated. The populations were the following: (i) 27 subjects living in the Paris area (mainland France, Europe), (ii) 21 university students living in Brest (Brittany, mainland France), (iii) 25 bank and insurance workers (BIW) living in seven distinct areas of Brittany (mainland France), (iv) 25 pig farmers (PF) living in the same seven areas as the BIW, (v) 93 ethnically homogeneous Wayampi Amerindians living in three villages of southern French Guyana (South America) with no modern sanitary or hygienic facilities, (vi) 46 women living in Cotonou (Benin, Africa), and (vii) 28 subjects living in Bogotá (Colombia, South America). The individuals in the BIW and PF populations in Brittany were matched for county of residence, age (20 to 60 years), and sex (13 men and 12 women). A subset of 25 Amerindians was also matched for age and sex with the BIW and PF populations. These matched populations had neither been hospitalized nor had taken antibiotics for at least 1 month before stool sampling. In all, 1,740 E. coli isolates were obtained after plating fresh fecal samples on Drigalski agar, with 5 or 10 randomly chosen E. coli isolates per individual.The...

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