A new animal product free defined medium for 2D and 3D culturing of normal and cancer cells to study cell proliferation and migration as well as dose response to chemical treatment.

Cell culturing methods are increasingly used to reduce and replace the use of live animals in biomedical research and chemical toxicity testing. Although live animals are avoided when using cell culturing methods, they often contain animal-derived components of which one of the most commonly used is foetal bovine serum (FBS). FBS is added to cell culture media among other supplements to support cell attachment/spreading and cell proliferation. The safety, batch-to-batch variation, and ethical problems with FBS are acknowledged and therefore world-wide efforts are ongoing to produce FBS free media. Here, we present the composition of a new defined medium with only human proteins either recombinant or derived from human tissues. This defined medium supports long-term culturing/routine culturing of normal cells and of cancer cells, and can be used for freezing and thawing of cells, i.e. for cell banking. Here, we show for our defined medium, growth curves and dose response curves of cells grown in two and three dimensions, and applications such as cell migration. Cell morphology was studied in real time by phase contrast and phase holographic microscopy time-lapse imaging. The cell lines used are human cancer-associated fibroblasts, keratinocytes, breast cancer JIMT-1 and MDA-MB-231 cells, colon cancer CaCo-2 cells, and pancreatic cancer MiaPaCa-2 cells as well as the mouse L929 cell line. In conclusion, we present the composition of a defined medium without animal-derived products which can be used for routine culturing and in experimental settings for normal cells and for cancer cells, i.e. our defined medium provides a leap towards a universal animal product free cell culture medium.

Rapid molecular detection of pathogenic microorganisms and antimicrobial resistance markers in blood cultures: evaluation and utility of the next-generation FilmArray Blood Culture Identification 2 panel.

Rapid detection of pathogens causing bloodstream infections (BSI) directly from positive blood cultures is of highest importance in order to enable an adequate and timely antimicrobial therapy. In this study, the utility and performance of a recently launched next-generation fully automated test system, the Biofire FilmArray® Blood Culture Identification 2 (BCID2) panel, was evaluated using a set of 103 well-characterized microbial isolates including 29 antimicrobial resistance genes and 80 signal-positive and 23 signal-negative clinical blood culture samples. The results were compared to culture-based reference methods, MALDI-TOF, and/or 16S rDNA sequencing. Of the clinical blood culture samples, 68 were monomicrobial (85.0%) and 12 polymicrobial (15.0%). Six samples contained ESBL (blaCTX-M), two MRSA (mecA), and three MRSE (mecA) isolates. In overall, the FilmArray BCID2 panel detected well on-panel targets and resistance markers from mono- and polymicrobial samples. However, one Klebsiella aerogenes and one Bacteroides ovatus were undetected, and the assay falsely reported one Shigella flexneri as Escherichia coli. Hence, the sensitivity and specificity for detecting microbial species were 98.8% (95%CI, 95.8-99.9%) and 99.9% (95%CI, 99.8-99.9%), respectively. The sensitivity and specificity for detecting of resistance gene markers were 100%. The results were available within 70 min from signal-positive blood cultures with minimal hands-on time. In conclusion, the BCID2 test allows reliable and simplified detection of a vast variety of clinically relevant microbes causing BSI and the most common antimicrobial resistance markers present among these isolates.

Clinical characteristics and evaluation of the incidence of cryptococcosis in Finland 2004-2018.

BACKGROUND: Cryptococcosis is one of the major causes of mortality among HIV patients worldwide. Though most often associated with late stage HIV infection/AIDS, a significant number of cases occur in other immunocompromised patients such as solid organ transplant recipients and patients with hematological malignancies. Immunocompromised patients are a heterogeneous group and their number increases constantly. Since little is known about the incidence and the clinical features of cryptococcosis in Northern Europe, our aim was to investigate the clinical characteristics of cryptococcosis patients in Finland. METHODS: We retrospectively reviewed the laboratory confirmed cryptococcosis cases in Finland during 2004-2018. Only those who were treated for cryptococcosis were included in the study. Initial laboratory findings and medical records were also collected. RESULTS: A total of 22 patients with cryptococcosis were included in our study. The annual incidence of cryptococcosis was 0.03 cases per 100,000 population. Ten patients were HIV-positive and 12 out of 22 were HIV-negative. Hematological malignancy was the most common underlying condition among HIV-negative patients. CONCLUSIONS: To our knowledge, this is the first study of the clinical presentation and incidence of cryptococcosis in Finland. We demonstrate that invasive cryptococcal infection occurs not only in HIV/AIDS patients or otherwise immunocompromised patients but also in immunocompetent individuals. Even though cryptococcosis is extremely rare in Finland, its recognition is important since the prognosis depends on rapid diagnostics and early antifungal therapy.

Clinical and microbiological factors associated with mortality in candidemia in adult patients 2007-2016.

Background: Candidemia is a life-threatening infection with high mortality. Our aim was to evaluate the Candida species distribution, antifungal susceptibilities and risk factors associated with 30-day mortality in candidemia in Southern Finland. Methods: We present a retrospective analysis of candidemia cases from the hospital district of Helsinki and Uusimaa during 2007-2016. Patients younger than 18 years old were excluded. A total of 386 candida isolates from 374 episodes of candidemia were identified in 350 adult patients. Results:Candida albicans was the leading cause of candidemia (60.4%), followed by C. glabrata (21.5%), C. parapsilosis (5.2%) and C. dubliniensis (5.2%). There was no statistically significant change in the distribution of C. albicans vs non-albicans species during the study period. Thirty-day overall mortality was 30.7%. When patients who received no antifungal treatment were excluded from the mortality analysis, 30-day mortality was 23.0%. Severity of underlying illnesses (OR 20.55, 95% CI 5.98-70.60), ICU stay at the onset of candidemia (OR 5.06, 95% CI 1.75-14.68) and age >65 years (OR 3.98, 95% CI 1.97-8.02) were independent risk factors of 30-day mortality in multivariable analysis. However, there was no statistically significant association between 30-day mortality and an early start of an effective antifungal. Conclusion: There was not a significant shift to non-albicans species as the cause of candidemia in Southern Finland during the 10-year study period. Furthermore, we did not find an association between 30-day mortality and the early start of an antifungal treatment. Comorbidity considerably increased the risk of fatal outcome.

Factor H binding as a complement evasion mechanism for an anaerobic pathogen, Fusobacterium necrophorum.

Fusobacterium necrophorum subspecies funduliforme is an obligate anaerobic Gram-negative rod causing invasive infections such as the life-threatening Lemierre's syndrome (sore throat, septicemia, jugular vein thrombosis, and disseminated infection). The aim of our study was to understand if and how F. necrophorum avoids C activation. We studied 12 F. necrophorum subsp. funduliforme strains isolated from patients with sepsis. All strains were resistant to serum killing after a 1-h incubation in 20% serum. The bacteria bound, at different levels, the C inhibitor factor H (fH). Binding was ionic and specific in nature and occurred via sites on both the N terminus and the C terminus of fH. Bound fH remained functionally active as a cofactor for factor I in the cleavage of C3b. Interestingly, patients with the most severe symptoms carried strains with the strongest ability to bind fH. An increased C3b deposition and membrane attack complex formation on the surface of a weakly fH-binding strain was observed and its survival in serum at 3.5 h was impaired. This strain had not caused a typical Lemierre's syndrome. These data, and the fact that fH-binding correlated with the severity of disease, suggest that the binding of fH contributes to virulence and survival of F. necrophorum subsp. funduliforme in the human host. Our data show, for the first time, that an anaerobic bacterium is able to bind the C inhibitor fH to evade C attack.