Over the last decade, methicillin-resistant Staphylococcus aureus (MRSA) strains have emerged as serious pathogens in the nosocomial and community setting. Hospitalization costs associated with MRSA infections are substantially greater than those associated with methicillin-sensitive S. aureus (MSSA) infections, and MRSA has wider economic effects that involve indirect costs to the patient and to society. In addition, there is some evidence suggesting that MRSA infections increase morbidity and the risk of mortality. Glycopeptides are the backbone antibiotics for the treatment of MRSA infections. However, several recent reports have highlighted the limitations of vancomycin, and its role in the management of serious infections is now being reconsidered. Several new antimicrobials demonstrate in vitro activity against MRSA and other Gram-positive bacteria. Data from large surveys indicate that linezolid, daptomycin, and tigecycline are almost universally active against MRSA. This review will briefly discuss the epidemiology, costs, outcome, and therapeutic options for the management of MRSA infections.

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No information is currently available on the influence of injectable second-line drugs on treatment outcomes of multidrug-resistant (MDR) and extensively drug-resistant (XDR) tuberculosis (TB) patients.To investigate this issue, a large series of MDR-and XDR-TB cases diagnosed in Estonia, Germany, Italy and the Russian Federation (Archangels Oblast) between 1999 and 2006 were analysed. All study sites performed drug susceptibility testing for first-and second-line anti-TB drugs, laboratory quality assurance and treatment delivery according to World Health Organization recommendations.Out of 4,583 culture-confirmed cases, 240 MDR-and 48 XDR-TB cases had a definitive outcome recorded (treatment success, death, failure). Among MDR-and XDR-TB cases, capreomycin resistance yielded a higher proportion of failure and death than capreomycin-susceptible cases. Resistance to capreomycin was independently associated with unfavourable outcome (logistic regression analysis: odds ratio 3.51).In the treatment of patients with multidrug-resistant and extensively drug-resistant tuberculosis, resistance to the injectable drug capreomycin was an independent predictor for therapy failure in this cohort. As Mycobacterium tuberculosis drug resistance is increasing worldwide, there is an urgent need for novel interventions in the fight against tuberculosis.

Interferon-c release assays based on region of difference 1 antigens have improved diagnosis of latent tuberculosis infection (LTBI). However, these tests cannot discriminate between recently acquired infection (higher risk of progression to active tuberculosis) and remote LTBI. The objective of the present study was to evaluate the T-cell interferon-c responses to Mycobacterium tuberculosis DosR-regulon-encoded antigens (latency antigens) compared with QuantiFERON TB-Gold In-Tube (QFT-GIT) in subjects at different stages of tuberculosis.A total of 16 individuals with remote LTBI and 23 with recent infection were studied; 15 controls unexposed to M. tuberculosis and 50 patients with active tuberculosis and 45 with cured tuberculosis were also analysed.The results indicated that subjects with remote LTBI showed significantly higher whole-blood interferon-c responses to M. tuberculosis latency antigen Rv2628 than did individuals with recent infection, active tuberculosis and controls (p,0.003), whereas no significant differences between these groups were found for other latency antigens tested (Rv2626c, Rv2627c, Rv2031c and Rv2032). The proportion of responders to Rv2628 was five-fold higher among QFT-GIT-positiveindividuals with remote infection than among those with recently acquired infection.These data suggest that responses to M. tuberculosis latency antigen Rv2628 may associate with immune-mediated protection against tuberculosis. In contact-tracing investigations, these preliminary data may differentiate recent (positive QFT-GIT results without responses to Rv2628) from remote infection (positive to both tests).

Tuberculosis (TB) is still the principal cause of death caused by a single infectious agent, and the balance between the bacillus and host defense mechanisms reflects the different manifestations of the pathology. The aim of this work was to study the role of myeloid-derived suppressor cells (MDSCs) during active pulmonary tuberculosis at the site of infection. We observed an expansion of MDSCs in the lung and blood of patients with active TB, which are correlated with an enhanced amount of nitric oxide in the plasma. We also found that these cells have the remarkable ability to suppress T-cell response, suggesting an important role in the modulation of the immune response against TB. Interestingly, a trend in the diminution of MDSCs was found after an efficacious anti-TB therapy, suggesting that these cells may be used as a potential biomarker for monitoring anti-TB therapy efficacy.