MALDI-TOF mass spectrometry is a diagnostic tool of microbial identification and characterization based on the detection of the mass of molecules. In the majority of clinical laboratories, this technology is currently being used mainly for bacterial diagnosis, but several approaches in the field of virology have been investigated. The introduction of this technology in clinical virology will improve the diagnosis of infections produced by viruses but also the discovery of mutations and variants of these microorganisms as well as the detection of antiviral resistance. This review is focused on the main current applications of MALDI-TOF MS techniques in clinical virology showing the state of the art with respect to this exciting new technology.

Nucleic acid amplification techniques are commonly used currently to diagnose viral diseases and manage patients with this kind of illnesses. These techniques have had a rapid but unconventional route of development during the last 30 years, with the discovery and introduction of several assays in clinical diagnosis. The increase in the number of commercially available methods has facilitated the use of this technology in the majority of laboratories worldwide. This technology has reduced the use of some other techniques such as viral culture based methods and serological assays in the clinical virology laboratory. Moreover, nucleic acid amplification techniques are now the methods of reference and also the most useful assays for the diagnosis in several diseases. The introduction of these techniques and their automation provides new opportunities for the clinical laboratory to affect patient care. The main objectives in performing nucleic acid tests in this field are to provide timely results useful for high-quality patient care at a reasonable cost, because rapid results are associated with improvements in patients care. The use of amplification techniques such as polymerase chain reaction, real-time polymerase chain reaction or nucleic acid sequence-based amplification for virus detection, genotyping and quantification have some advantages like high sensitivity and reproducibility, as well as a broad dynamic range. This review is an up-to-date of the main nucleic acid techniques and their clinical applications, and special challenges and opportunities that these techniques currently provide for the clinical virology laboratory.

Fungal microorganisms are still a rare cause of bone and joint infections. We report a new case of knee prosthetic joint infection due to Candida albicans in a patient with a previous two-stage right knee arthroplasty for septic arthritis due to S. epidermidis occurred several months ago. Moreover, the treatment in 76 cases of Candida prosthetic joint infection has been discussed. Forty patients were female and mean age at diagnosis was 65.7 (± SD 18) yrs. No risk factors for candidal infection were found in 25 patients. Infection site was the knee in 38 patients and hip in 36; pain was present in 44 patients and swelling in 24. The most frequent species was C. albicans, followed by C. parapsilosis. Eleven patients were only treated with antifungal drugs being the outcome favourable in all of them. Two-stage exchange arthroplasty was performed in 30 patients, and resection arthroplasty in other 30; in three patients one-stage exchange arthroplasty was done. A favourable outcome was found in 58 patients after antifungal plus surgical treatment, in 11 after antifungal treatment alone and in one after surgery alone. The type of treatment is still not clearly defined and an algorithm for treatment in fungal PJI should be established, but various types of surgical procedures may be applied.

Background: The clinical and microbiological characteristics of prosthetic joint infection (PJI) caused by Candida species is described, including 72 cases in the literature and a case of Candida glabrata infection handled at the present centre. Methods: We describe one patient and using the key words ‘fungal prosthetic joint infection’ and ‘candida prosthetic joint infection’ we searched MEDLINE (National Library of Medicine, Bethesda, MD), Web of Science, CINAHL and Cochrane systematic review databases for case reports of this condition. Results: Out of the 73 patients, 38 were female; mean age at diagnosis was 65.7 (± SD 18) yrs; 50 had risk factors for candidal infection such as systemic disease (e.g. rheumatoid arthritis, Sjogren’s syndrome, systemic lupus erythematosus) and/or immunosuppressive therapy in 18 (24.6%) cases, diabetes mellitus in 14 (19.1%), immunosuppression due to malignant or chronic disease in 24 (32.8%) and long-term antibiotic use in four (5.4%) patients. Infection site was the knee in 36 patients and hip in 35; pain was present in 43 patients and swelling in 23 and the mean surgery-diagnosis interval was 32 months. The most frequent species was C. albicans, followed by C. parapsilosis. The diagnosis was obtained from joint fluid aspirate in 33 cases and intra-operative samples in 16. Susceptibility to antifungals was tested in only 21 isolates. The most frequently used antifungals were fluconazole and amphotericin B. Two-stage exchange arthroplasty was performed in 30 patients and resection arthroplasty in 31; 56 patients were cured with a combination of medical and surgical treatment; one patient died from the infection. Conclusion: PJI caused by Candida requires a high index of suspicion; surgery with long-term antifungal therapy is recommended.

Human embryonic stem cells (hESCs) are expected to open up new avenues in regenerative medicine by allowing the generation of transplantable cells to be used in future cell replacement therapies. Maintenance of hESCs in the presence of xenogenic compounds is likely to prevent their use in future therapeutic applications in humans. Recently, it has been claimed that human foreskin-derived human embryonic fibroblast (HEFs) and human adult marrow cells have the ability to support prolonged expansion of hESCs in culture similar to murine feeders. Here, to minimize the use of xenogenic components for hESC maintenance, we performed transmission electron microscopy-based microbiological studies in an attempt to implement a microbiological Quality Assurance Program in Stem Cell Banks by determining the potential presence of viral particles in MEFs compared with human HEFs and bone marrow-derived mesenchymal cells. We observed in three out of nine MEF samples (33.3%) viruses belonging to the Retroviridae family. Within the Retroviridae family, these viruses have a C morphology, which indicates they belong to the subfamily Orthoretroviridae. In contrast, no viral particles could be observed in either the HEF samples (n = 5) or the human BM-derived mesenchymal cells (n = 9) analyzed. Based on these experimental microbiological data, we recommend the implementation of microbiological Quality Assurance Programs by means of transmission electron microscopy as a routine technique to assess the potential presence of viral particles in any feeder cell used in stem cell banks and support the use of human cells rather than murine cells as feeders to maintain hESC cultures in an undifferentiated state.