Carbapenem-resistant and carbapenem-susceptible isogenic isolates of Klebsiella pneumoniae ST101 causing infection in a tertiary hospital

Background: In this study we describe the clinical and molecular characteristics of an outbreak due to carbapenem-resistant Klebsiella pneumoniae (CR-KP) producing CTX-M-15 and OXA-48 carbapenemase. Isogenic strains, carbapenem-susceptible K. pneumoniae (CS-KP) producing CTX-M-15, were also involved in the outbreak. Results: From October 2010 to December 2012 a total of 62 CR-KP and 23 CS-KP were isolated from clinical samples of 42 patients (22 had resistant isolates, 14 had susceptible isolates, and 6 had both CR and CS isolates). All patients had underlying diseases and 17 of them (14 patients with CR-KP and 3 with CS-KP) had received carbapenems previously. The range of carbapenem MICs for total isolates were: imipenem: 2 to >32 mu g/ml vs. <2 mu g/ml; meropenem: 4 to >32 mu g/ml vs. <2 mu g/ml; and ertapenem: 8 to >32 mu g/ml vs. <2 mu g/ml. All the isolates were also resistant to gentamicin, ciprofloxacin, and cotrimoxazole. Both types of isolates shared a common PFGE pattern associated with the multilocus sequence type 101 (ST101). The bla(CTX-M-15) gene was detected in all the isolates, whereas the bla(OXA-48) gene was only detected in CR-KP isolates on a 70 kb plasmid. Conclusions: The clonal spread of K. pneumoniae ST101 expressing the OXA-48 and CTX-M-15 beta-lactamases was the cause of an outbreak of CR-KP infections. CTX-M-15-producing isolates lacking the blaOXA-48 gene coexisted during the outbreak.This study was supported by CIBER de Enfermedades Respiratorias (CIBERES - CB06/06/0037), ISCIII - Instituto de Salud Carlos III, Madrid, Spain

First identification of NDM-5 associated with OXA-181 in Escherichia coli

Emerging Microbes and Infections (2016) 5, e30; doi:10.1038/emi.2016.24; published online 6 April 201

Influence of Empiric Therapy with a β-Lactam Alone or Combined with an Aminoglycoside on Prognosis of Bacteremia Due to Gram-Negative Microorganisms▿

Evidence supporting the combination of aminoglycosides with β-lactams for Gram-negative bacteremia is inconclusive. We have explored the influence on survival of empirical therapy with a β-lactam alone versus that with a β-lactam-aminoglycoside combination by retrospectively analyzing a series of bacteremic episodes due to aerobic or facultative Gram-negative microorganisms treated with single or combination therapy. The outcome variable was a 30-day mortality. Prognostic factors were selected by regression logistic analysis. A total of 4,863 episodes were assessed, of which 678 (14%) received combination therapy and 467 (10%) were fatal. Factors independently associated with mortality included age greater than 65 (odds ratio [OR], 2; 95% confidence interval [CI], 1.6 to 2.6), hospital acquisition (OR, 1.5; 95% CI, 1.2 to 1.9), a rapidly or ultimately fatal underlying disease (OR, 2.5; 95% CI, 2 to 3.2), cirrhosis (OR, 1.9; 95% CI, 1.4 to 2.6), prior corticosteroids (OR, 1.5; 95% CI, 1.1 to 2), shock on presentation (OR, 8.8; 95% CI, 7 to 11), pneumonia (OR, 2.8; 95% CI, 1.9 to 4), and inappropriate empirical therapy (OR, 1.8; 95% CI, 1.3 to 2.5). Subgroup analysis revealed that combination therapy was an independent protective factor in episodes presenting shock (OR, 0.6; 95% CI, 0.4 to 0.9) or neutropenia (OR, 0.5; 95% CI, 0.3 to 0.9). Combination therapy improved the appropriateness of empirical therapy in episodes due to extended-spectrum β-lactamase (ESBL)- or AmpC-producing Enterobacteriaceae and Pseudomonas aeruginosa. In patients with Gram-negative bacteremia, we could not find an overall association between empirical β-lactam-aminoglycoside combination therapy and prognosis. However, a survival advantage cannot be discarded for episodes presenting shock or neutropenia, hence in these situations the use of combination therapy may still be justified. Combination therapy also should be considered for patients at risk of being infected with resistant organisms, if only to increase the appropriateness of empirical therapy

Gastrointestinal simulation model TWIN-SHIME shows differences between human urolithin-metabotypes in gut microbiota composition, pomegranate polyphenol metabolism, and transport along the intestinal tract

A TWIN-SHINE system was used to compare the metabolism of pomegranate polyphenols by the gut microbiota from two individuals with different urolithin metabotypes. Gut microbiota, ellagitannin metabolism, short-chain fatty acids (SCFA), transport of metabolites, and phase II metabolism using Caco-2 cells were explored. The simulation reproduced the in vivo metabolic profiles for each metabotype. The study shows for the first time that microbial composition, metabolism of ellagitannins, and SCFA differ between metabotypes and along the large intestine. The assay also showed that pomegranate phenolics preserved intestinal cell integrity. Pomegranate polyphenols enhanced urolithin and propionate production, as well as Akkermansia and Gordonibacter prevalence with the highest effect in the descending colon. The system provides an insight into the mechanisms of pomegranate polyphenol gut microbiota metabolism and absorption through intestinal cells. The results obtained by the combined SHIME/Caco-2 cell system are consistent with previous human and animal studies and show that although urolithin metabolites are present along the gastrointestinal tract due to enterohepatic circulation, they are predominantly produced in the distal colon region