Comparative effects of ertapenem, imipenem, and meropenem on the colonization of the gastrointestinal tract of mice by Candida albicans

Risk factors for candidemia: a prospective matched case-control study

Background

Candidemia is an opportunistic infection associated with high morbidity and mortality in patients hospitalized both inside and outside intensive care units (ICUs). Identification of patients at risk is crucial to ensure prompt antifungal therapy. We sought to assess risk factors for candidemia and death, both outside and inside ICUs.

Methods

This prospective multicenter matched case-control study involved six teaching hospitals in Switzerland and France. Cases were defined by positive blood cultures for Candida sp. Controls were matched to cases using the following criteria: age, hospitalization ward, hospitalization duration, and, when applicable, type of surgery. One to three controls were enrolled by case. Risk factors were analyzed by univariate and multivariate conditional regression models, as a basis for a new scoring system to predict candidemia.

Results

One hundred ninety-two candidemic patients and 411 matched controls were included. Forty-four percent of included patients were hospitalized in ICUs, and 56% were hospitalized outside ICUs. Independent risk factors for candidemia in the ICU population included total parenteral nutrition, acute kidney injury, heart disease, prior septic shock, and exposure to aminoglycoside antibiotics. Independent risk factors for candidemia in the non-ICU population included central venous catheter, total parenteral nutrition, and exposure to glycopeptides and nitroimidazoles. The accuracy of the scores based on these risk factors is better in the ICU than in the non-ICU population. Independent risk factors for death in candidemic patients included septic shock, acute kidney injury, and the number of antibiotics to which patients were exposed before candidemia.

Discussion

While this study shows a role for known and novel risk factors for candidemia, it specifically highlights important differences in their distribution according to the hospital setting (ICU versus non-ICU).

Conclusion

This study provides novel risk scores for candidemia accounting for the hospital setting and recent progress in patients’ management strategies and fungal epidemiology.

Cefepime and Amoxicillin Increase Metabolism and Enhance Caspofungin Tolerance of Candida albicans Biofilms

It is well known that prolonged antibiotic therapy alters the mucosal microbiota composition, increasing the risk of invasive fungal infection (IFI) in immunocompromised patients. The present study investigated the direct effect of β-lactam antibiotics cefepime (CEF) and amoxicillin (AMOX) on biofilm production by Candida albicans ATCC 10231. Antibacterials at the peak plasmatic concentration of each drug were tested against biofilms grown on polystyrene surfaces. Biofilms were evaluated for biomass production, metabolic activity, carbohydrate and protein contents, proteolytic activity, ultrastructure, and tolerance to antifungals. CEF and AMOX enhanced biofilm production by C. albicans ATCC 10231, stimulating biomass production, metabolic activity, viable cell counts, and proteolytic activity, as well as increased biovolume and thickness of these structures. Nevertheless, AMOX induced more significant changes in C. albicans biofilms than CEF. In addition, it was shown that AMOX increased the amount of chitin in these biofilms, making them more tolerant to caspofungin. Finally, it was seen that, in response to AMOX, C. albicans biofilms produce Hsp70 - a protein with chaperone function related to stressful conditions. These results may have a direct impact on the pathophysiology of opportunistic IFIs in patients at risk.

Carbapenems and alternative β-lactams for the treatment of infections due to extended-spectrum β-lactamase-producing Enterobacteriaceae: What impact on intestinal colonisation resistance?

The ongoing pandemic of extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-E) is responsible for a global rise in carbapenem consumption that may hasten the dissemination of carbapenemase-producing Enterobacteriaceae (CPE). Hence, carbapenem sparing through the use of alternative β-lactams is increasingly considered as a potential option in patients with ESBL-E infections. However, at the individual level, this strategy implies an in-depth understanding of how carbapenems and their alternatives impair the gut microbiota, especially the anaerobic bacteria and the colonisation resistance (CR) that it confers. In this review, we sought to appraise the impact of carbapenems and their main alternatives for ESBL-E infections (namely β-lactam/β-lactamase inhibitor combinations, cephamycins and temocillin) on the gut ecosystem and the resulting hazard for acquisition of CPE. Although limited, the available evidence challenges our perception of the ecological side effects of these antimicrobials and highlights knowledge gaps regarding antibiotic-induced alterations in intestinal CR. These alterations may depend not only on anti-anaerobic properties but also on a panel of parameters with marked interindividual variability, such as baseline characteristics of the gut microbiota or the degree of biliary excretion for the considered drug. In the current context of ESBL-E dissemination and increasing opportunities for carbapenem-sparing initiatives, large, comparative, high-quality studies based on new-generation sequencing tools are more than ever warranted to better define the positioning of alternative β-lactams in antimicrobial stewardship programmes.

Factors Influencing Non-albicans Candidemia: A Case-Case-Control Study

The study identified factors predisposing to non-albicans candidemia with special interest to prior antimicrobial treatment. A retrospective, case-case-control study was performed at the University Hospital of Heraklion, Greece, from November 2007 through September 2011 including adult patients. The study had three groups. The first included 58 patients with non-albicans candidemia, the second 48 with C. albicans candidemia, while the third (control) 104 without candidemia. Each of the two candidemia groups was compared with the control using multivariate logistic regression model. The mean (SD) age of the non-albicans, the albicans and the control patients was 67 (12), 67 (18) and 59 (19) years, respectively. The most common non-albicans Candida spp. isolated were C. parapsilosis in 19 patients (33%), C. glabrata in 17 (29%) and C. tropicalis in 15 (26%). Independent risk factors for non-albicans candidemia were prior treatment with quinolones (p < 0.001), b-lactam-b-lactamase inhibitors (p = 0.011) and presence of central venous catheter (p = 0.05), while for C. albicans candidemia were prior treatment with quinolones (p < 0.001), carbapenems (p = 0.003) along with cardiac disease (p < 0.001). Neither duration of hospitalization nor in-hospital mortality [41% for the non-albicans vs 29% for C. albicans group (p = 0.192)] was significantly different between the two candidemia groups. The study reveals the role of antimicrobial exposure as a risk factor for candidemia caused by different species. Prior treatment with b-lactam-b-lactamase inhibitors was associated with non-albicans, while with carbapenems with C. albicans candidemia. Prior use of quinolones was associated with candidemia in general.

Effects of carbapenems and their combination with amikacin on murine gut colonisation by Candida albicans

Carbapenems are broad-spectrum antibiotics increasingly used for the treatment of severe infections. We evaluated the effects of four carbapenems given as monotherapies or in combination with amikacin on the level of gastrointestinal colonisation by Candida albicans in a previously established mouse model. Adult male Crl : CD1 (ICR) BR mice were fed chow containing C. albicans or regular chow. The mice fed with Candida chow had their gut colonised by the yeast. Both groups were subsequently given imipenem, meropenem, ertapenem, doripenem or their combination with amikacin or normal saline subcutaneously for 10 days. Stool cultures were performed immediately before, at the end and 1 week after discontinuation of treatment. Candida-colonised mice treated with the antibiotics had higher counts of the yeast in their stools than control C. albicans-colonised animals treated with saline. All four carbapenems and their combination with amikacin caused a significant increase in C. albicans concentration. Mice fed regular chow and treated with the study antibiotics or saline did not have any Candida in their stools. Dissemination of Candida was not detected in any animal. These data suggest that carbapenems and carbapenem plus amikacin induce substantial increases in the murine intestinal concentration of C. albicans.