Vitamin D and infectious diseases.

In the early 1920s the antirachitic effect of food irradiated with ultraviolet light and cod liver oil has been recognized. The antirachitic substance was identified and called "vitamin D". Since then the key role of vitamin D in calcium and bone homeostasis has been investigated. Moreover, it has been recognized that vitamin D is able to modulate a variety of processes and regulatory systems such as host defense, inflammation, immunity, and repair. According to recent studies, vitamin D deficiency is likely to be an important etiological factor in the pathogenesis of many chronic diseases, as well as it has been associated with higher mortality rate for respiratory disease. In this regard, either observational studies aimed to verify an association between low vitamin D level and the incidence of respiratory tract infections (RTIs) or clinical trials on the effect of vitamin D as a supplementary treatment in RTIs patients have been presented in the emerging clinical literature. Conflicting results have been demonstrated in several randomized, double-blind, placebo controlled trials concerning the vitamin D treatment in tuberculosis. Some studies suggest a beneficial effect by vitamin D but it could not be reproduced in larger studies so far. In conclusion, although basic science research suggests that vitamin D may play an important role in modulating immune functions, no strong evidence exists whether correction of vitamin D depletion may be useful in the prevention or treatment of infections. Further and larger studies may clarify the role of vitamin D in infection.

Rapid and sensitive detection of bla KPC gene in clinical isolates of Klebsiella pneumoniae by a molecular real-time assay.

BACKGROUND: The aim of this study was the rapid identification of bla KPC gene in 38 Klebsiella pneumoniae clinical isolates with reduced susceptibility to carbapenems. The modified Hodge Test (MHT) was carried out to phenotypically determine whether resistance to carbapenems was mediated by a carbapenemase. The detection of the bla KPC gene was performed by real-time acid nucleic sequence-based amplification (NASBA™™), specifically designed for the detection of KPC RNA target. RESULTS: Thirty-two/38 isolates evaluated by MHT showed the production of carbapenemases, while all the strains exhibited the production of KPC by inhibition test with phenylboronic acid (the combined disk test with IPM/IPM plus phenylboronic acid). The detection of bla KPC gene by Nuclisens EasyQ KPC yielded positive results in 38/38 (100%) strains. The presence of bla KPC gene was confirmed in all K. pneumoniae isolates when tested by the gold standard PCR assay. CONCLUSIONS: In consideration of the serious challenge represented by infections due to K. pneumoniae it appears necessary the rapid identification of carbapenemases in clinical settings as it is made possible by the use of NASBA™ assay.

Tuberculous otitis media with facial paralysis: a clinical and microbiological diagnosis-a case report.

The tuberculosis of the ear is rare, and in most cases the clinical picture resembles that of a chronic otitis media. The diagnosis is often delayed, and this can lead to irreversible complications such as hearing loss and/or facial paralysis. In view of its rare occurrence, we report a case of primary tuberculous otitis media in a 87-year-old female patient. The diagnosis was made on the basis of both histological and microbiological findings. In particular, gene amplification techniques such as real-time polymerase chain reaction are useful method for rapid diagnosis and detecting tuberculous bacilli usually present at very low number. Early diagnosis is essential for the prompt institution of antituberculous therapy.

The central region of the msp gene of Treponema denticola has sequence heterogeneity among clinical samples, obtained from patients with periodontitis.

BACKGROUND: Treponema denticola is an oral spirochete involved in the pathogenesis and progression of periodontal disease. Of its virulence factors, the major surface protein (MSP) plays a role in the interaction between the treponeme and host. To understand the possible evolution of this protein, we analyzed the sequence of the msp gene in 17 T. denticola positive clinical samples. METHODS: Nucleotide and amino acid sequence of MSP have been determined by PCR amplification and sequencing in seventeen T. denticola clinical specimens to evaluate the genetic variability and the philogenetic relationship of the T. denticola msp gene among the different amplified sequence of positive samples. In silico antigenic analysis was performed on each MSP sequences to determined possible antigenic variation. RESULTS: The msp sequences showed two highly conserved 5' and 3' ends and a central region that varies substantially. Phylogenetic analysis categorized the 17 specimens into 2 principal groups, suggesting a low rate of evolutionary variability and an elevated degree of conservation of msp in clinically derived genetic material. Analysis of the predicted antigenic variability between isolates, demonstrated that the major differences lay between amino acids 200 and 300. CONCLUSION: These findings showed for the first time, the nucleotide and amino acids variation of the msp gene in infecting T. denticola, in vivo. This data suggested that the antigenic variability found in to the MSP molecule, may be an important factor involved in immune evasion by T. denticola.

A carbapenem-resistant Klebsiella pneumoniae isolate harboring KPC-1 from Italy.

Carbapenem-resistant gram-negative pathogens represent an emerging threat to the management of hospital-acquired infections. Although the isolation of carbapenem-resistant enterobacteriaceae remains unusual, the frequency of carbapenemases producing Klebsiella pneumoniae is increasing in different geographic regions: the majority of isolates has been collected in the USA, but recently KPC-producing K. pneumoniae were reported from China, Israel, Greece, France, Norway and Sweden. We report a KPC 1-producing K. pneumoniae isolate from Italy. This datum enlarges the geographical area where the KPC-producing K. pneumoniae strains are diffuse.

Antimicrobial profiles of Prevotella spp. and Fusobacterium nucleatum isolated from periodontal infections in a selected area of southern Italy.

In view of the increasing antibiotic resistance of anaerobic Gram-negative bacteria, we determined the antimicrobial profile of 55 periodontal anaerobic Gram-negative bacteria correlated with human infections, comprising 16 strains of Fusobacterium nucleatum and 39 strains of Prevotella spp. isolated from periodontal pockets of 26 adults suffering from chronic periodontitis. All the strains of F. nucleatum were susceptible to amoxicillin/clavulanic acid, doxycycline, metronidazole, moxifloxacin and levofloxacin, whilst 2/16 strains were both resistant to amoxicillin and beta-lactamase-positive and 11/16 were resistant to clarithromycin. All of the Prevotella strains were susceptible to amoxicillin/clavulanic acid, doxycycline and metronidazole, whereas 7/39 strains were beta-lactamase-positive and resistant to amoxicillin, 5/39 were resistant to clarithromycin and 3/39 were resistant to both moxifloxacin and levofloxacin. Our findings confirm that there is an increasing need to encourage practitioners to use laboratory investigations to limit the risk of an incorrect therapeutic approach and to avoid the overuse of antimicrobial agents.

Utility of gas chromatography for rapid identification of mycobacterial species frequently encountered in clinical laboratory.

Over the last years, the clinical importance of mycobacteria has been raised. In this regard, it is important their identification in order to establish either the clinical significance or the appropriate therapy of the disease. Biochemical tests are usually time consuming until the report of results, that is why more rapid techniques are needed. As an alternative identification method, we have used a commercially available system for microbial identification based on whole cellular fatty acids analysis using gas-chromatography (GC). Sixty-eight strains of Mycobacterium tuberculosis, Mycobacterium gordonae, Mycobacterium xenopi, Mycobacterium kansasii, Mycobacterium fortuitum, and Mycobacterium avium-intracellulare were clearly identified by their unique fatty acid profile using the Sherlock Microbial Identification System (MIS). The results were in agreement with those obtained with traditional methods. This method is highly automated, rapid, easy to perform with a sample preparation for lipid analysis which is neither time consuming nor requiring a particular expertise. On this basis the MIS-GC method for the identification of some clinically important mycobacteria appears to be suitable for routine clinical use.