Enhanced growth of Staphylococcus aureus after nitric oxide supplementation during simulated extracorporeal circulation.

BACKGROUND: Several factors contribute to postoperative bacterial infections in cardiac surgery. Long operation times and the use of extracorporeal circulation increase the risk of infection. Nitric oxide has been shown to possess a broad spectrum antimicrobial effect. METHODS: In this study, we investigated the effect of nitric oxide on S. AUREUS growth in whole blood during simulated extracorporeal circulation. RESULTS: S. AUREUS growth increased 6.2-fold after 180 min SECC in the presence of nitric oxide. Leukocyte counts remained unchanged without any differences between the groups. We observed a steady increase in markers of oxidative stress and activity of the innate immune system. Myeloperoxidase levels increased 8-fold, and C3a and terminal complement complex by 2-fold after 180 min. CONCLUSION: S. AUREUS growth is not due to the effect of nitric oxide on the innate immune system but from its effect on the bacteria itself. It has been shown that nitric oxide stimulates the expression of inducible lactate dehydrogenase, specific to S. AUREUS, which improves its resistance to oxidative stress, and may give S. AUREUS a survival advantage resulting in increased growth.

Impact of prolonged storage of clinical samples at 4°C on the recovery of dermatophytes by culture or PCR analysis.

Dermatophytes are common pathogens in superficial mycoses that are routinely identified by culture or PCR analysis of freshly collected skin, nail or hair specimens. Although clinical samples are normally processed without delay, practical or research issues may necessitate sample storage until later analysis. However, the influence of extended sample storage on the ability to recover fungi by culture vs. PCR analysis has not been specifically studied. Here, a total of 172 dermatological samples collected from 2013-2015 were examined before and after refrigerated storage at 4°C for 10.2-32.3 (mean 25.6) months. By culture, 35% of the dermatophyte-containing fresh samples remained positive at re-examination. At species level, only 19% of initially Trichophyton rubrum-positive samples yielded a positive result after refrigeration, whereas few samples containing Trichophyton violaceum, Microsporum canis or Microsporum audouinii remained culture-positive. Using PCR, 76% of dermatophyte DNA-positive fresh samples were still positive at re-analysis. Notably, 92% of the samples targeted by the T. rubrum DNA primer remained positive after storage. Hence, PCR analysis is more favourable than cultivation with regard to the detectability of dermatophytes in long-term refrigerated clinical samples.

Effectiveness of automated ultraviolet-C light for decontamination of textiles inoculated with Enterococcus faecium.

Healthcare textiles are increasingly recognized as potential vehicles for transmission of hospital-acquired infections. This study tested the ability of an automated ultraviolet-C (UV-C) room disinfection device (Tru-D Smart UV-C) to decontaminate textiles inoculated with Enterococcus faecium in a clinical setting. Contaminated polycotton (50/50 polyester/cotton) swatches were distributed to predefined locations in a ward room and exposed to UV-C light. UV-C decontamination reduced E. faecium counts by a mean log10 reduction factor of 1.37 (all P = 0.005, Wilcoxon signed rank test). UV-C decontamination may be a feasible adjunctive measure to conventional laundering to preserve the cleanliness of healthcare textiles in ward rooms.

[Factors of compliance with the wearing of elastic compression stockings in a Sub-Saharan population]. / Facteurs de l'observance du port du bas de compression élastique dans une population noire africaine.

INTRODUCTION: Elastic venous compression is the basic treatment of chronic venous insufficiency (CVI) and deep vein thrombosis (DVT). Very little data exist in sub-Saharan Africa concerning the wearing of compression stockings. AIM: To determine the factors of compliance with wearing elastic compression stockings. MATERIALS AND METHODS: This retrospective cross-sectional descriptive and analytical study involved 200 consecutive patients (93 cases of DVT, 94 cases of CVI, 13 cases of DVT and CVI). Data on compliance with wearing compression stockings and the factors influencing this compliance were collected. RESULTS: The average age was 51±15 years old (range 17 and 91 years old). The sex ratio was 1. The majority of patients (78.5%) performed their occupation in a standing position, for more than 8hours per day for 80.5%. DVT were preferentially on the left side (52.9%) and proximal (44.4%). Concerning the CVI, the predominant symptoms were class C3 (52.3%), C4 and C5 (43.9%) of the CEAP classification. Bilateral involvement was dominant (53.3%) and the large saphenous vein was the most affected (66.9%) compared with 33.1% for the small saphenous vein exclusively. The most common type of stockings prescribed was the lower mid-thighs (57%), followed by the pantyhose (30%), in classes 3 (63%) and 2 (36.5%). The majority of patients (75%) agreed to wear their stockings after prescription with a good compliance rate of 58.5% at the beginning of the prescription. At the time of the study, this rate was 11%. The optimal duration of compliance with wearing compression stockings was 6 months (64%). Over 12 months this rate fell to 7.5%. The main causes were stocking-related compression discomfort (36.7%), patient neglect (21.5%), threading difficulties (16.9%), and an unfavorable working environment (8.7%). The determining factors of compliance with wearing of stockings were living in a couple (68.4% vs 54.2, P=0.04), CVI (53% vs 38.2%, P=0.04) and C3 (39% vs 80%), C4 (37.5% vs 17%), C5 (18% vs 3%) CVI (P=0.0005). CONCLUSION: Compliance with wearing elastic compression stockings is mediocre. The main factors of non-compliance are discomfort, threading difficulties and patient neglect.

Legionellosis acquired through a dental unit: a case study.

In 2012, an elderly immunocompromised man died from legionellosis at a hospital in Uppsala, Sweden. The patient had visited a dental ward at the hospital during the incubation period. Legionella spp. at a concentration of 2000 colony-forming units/L were isolated from the cupfiller outlet providing water for oral rinsing. Isolates from the patient and the dental unit were Legionella pneumophila serogroup 1, subgroup Knoxville and ST9. Pulsed-field gel electrophoresis and whole-genome sequencing strongly suggested that the isolates were of common origin. This report presents one of few documented cases of legionellosis acquired through a dental unit.

Propensity to release endotoxin after two repeated doses of cefuroxime in an in vitro kinetic model: higher release after the second dose.

OBJECTIVES: To study endotoxin release from two strains of Escherichia coli after exposure to two repeated doses of cefuroxime in an in vitro kinetic model. METHODS: Cefuroxime in concentrations simulating human pharmacokinetics was added to the bacterial solution with a repeated dose after 12 h. In another experiment, tobramycin was given concomitantly with the second dose of cefuroxime. Samples for viable counts and endotoxin analyses were drawn before the addition of antibiotics and at 2 and 4 h after each dose. RESULTS: The propensity to release endotoxin, expressed as log10 endotoxin release (EU)/log10 killed bacteria, was higher after the second than after the first dose, 0.80+/-0.04 and 0.65+/-0.01, respectively, in the ATCC strain and 0.80+/-0.04 and 0.65+/-0.02, respectively, in the clinical strain (P<0.001). Endotoxin was released earlier after the second dose (P<0.001). Addition of tobramycin at the second dose reduced the endotoxin release in comparison with that of cefuroxime alone (P<0.001). CONCLUSIONS: The propensity to liberate endotoxin is higher after the second dose of cefuroxime than after the first, resulting in a higher release of endotoxin than expected from bacterial count. The release after the second dose can be reduced by the addition of tobramycin.

Pharmacodynamic studies of moxifloxacin and erythromycin against intracellular Legionella pneumophila in an in vitro kinetic model.

BACKGROUND: Newer quinolones are highly active against Legionella pneumophila. Since this pathogen is intracellular, standard in vitro susceptibility tests may not accurately predict clinical efficacy. Few models for studies of intracellular Legionella have been described. In this study, we determined the pharmacodynamic activity of moxifloxacin against intracellular L. pneumophila in comparison with erythromycin. METHODS: A kinetic model for intracellular studies was constructed in which human pharmacokinetics could be simulated. The model consisted of a glass chamber with two exits and a metal rack fitting cell culture inserts. The inserts had a bottom membrane where cells could be cultured while nutrients and antibiotics passed through. The inserts were prepared with a monolayer of HEp-2 cells, which were exposed to a culture of L. pneumophila. At regular intervals cells were harvested and lysed, viable intracellular bacteria counted and compared with untreated controls. RESULTS: The MICs were 0.0156 mg/L for moxifloxacin and 0.5 mg/L for erythromycin. The human pharmacokinetics were simulated in the model with a mean initial antibiotic concentration of 2.4 mg/L for moxifloxacin and 8.4 mg/L for erythromycin. The mean half-life was 9 h for moxifloxacin and 3.4 h for erythromycin. At 12 h, a 2 log(10) reduction in bacterial counts was seen in cells treated with moxifloxacin and no regrowth was detected at 24 h. Cells treated with erythromycin showed no reduction in intracellular L. pneumophilia at 12 h or 24 h. In experiments using static concentrations of 9 mg/L of erythromycin, similar results were obtained. CONCLUSIONS: In this model, moxifloxacin exerts a significantly better antibacterial effect against intracellular L. pneumophila compared with erythromycin.