Nitrogen laser irradiation (337 nm) causes temporary inactivation of clinical isolates of Mycobacterium tuberculosis

Low level nitrogen laser therapy in pulmonary tuberculosis

BACKGROUND AND AIMS

WHO estimated 9 million new Tuberculosis cases and 1.5 million TB deaths in 2013. Globally 480000 Multi drug resistant tuberculosis cases were noted and majority of them were in India, China and Russian federation. Multi drug resistant tuberculosis cases are difficult to treat and have high mortality. Presently, it was aimed to assess prevalence of drug resistance in M. tuberculosis isolates in Central India, to check the in-vitro effect of N2 Laser on M. tuberculosis and to study the therapeutic effect of intra cavitary N2 laser on pulmonary Tuberculosis cases not responding to chemotherapy.

MATERIALS AND METHODS

Drug sensitivity testing was carried out on 567 isolates of M. tuberculosis by proportion method. To check the effect of N2 laser on M. tuberculosis, suspension spread on LJ plate and part of the plate exposed to N2 laser for 10 min and plate incubated for 4 weeks to see the effect. For exposure to lung cavity a needle was introduced into the lung through which fiber was passed to the cavity for N2 laser irradiation for 10 min.

RESULTS

Only 12.8% isolates of M. tuberculosis were sensitive to all anti-Tubercular drugs and 21.5% were found to be resistant to Rifampicin qualifying definition of Multi drug resistant tuberculosis. Bactericidal effect for N2 laser was seen in-vitro on exposure to N2 laser. Clinical improvement occurred in 90% of the 96 patients; 60% of the patients showed improvement on their X-rays and 75% turned out to be Acid fast bacilli smear negative in 4 to 15 days.

CONCLUSIONS

Intra-cavitory N2 laser therapy was found to have remarkable success as an adjunct to chemotherapy.

Effects of HeNe laser irradiation on experimental paracoccidioidomycotic lesions

Paracoccidioidomycosis (PCM) is the most prevalent human mycosis in Latin America. The infection is thought to take place firstly in the lungs and then may disseminate to other organs and tissues. Treatment by currently available antifungals is lengthy, the drugs may have undesirable side effects, and some are costly. Occasional resistant strains of Paracoccidioides brasiliensis, the causative agent of PCM, have been reported. So, the search for more efficient treatments or adjuvant therapies has to be continued. In this work, we evaluated the effects of HeNe laser irradiation on cutaneous inflammatory lesions caused by the inoculation of 5 x 10(6)/0.1ml yeasts cells into the back footpad of Balb/c mice. HeNe irradiation (lambda=632.8nm, 3mW, incident energy of 3J/cm(2)) was applied at days 7, 8 and 9 post-infection and histological and immunohistochemical analysis were done. Unirradiated animals were used as controls. The results showed that laser-treated mice presented reduction of footpad edema, faster cutaneous wound healing, confluent granuloma, diffuse- and more loosely distributed immunolabeling for TNF-alpha, enhanced labeling of IFN-gamma and any P. brasiliensis form detected, whereas multiple viable fungi were seen in diffuse widespread granulomas obtained from non-treated mice foot-pad. Fungi that were harvested from laser-treated animals presented no capability of growth in vitro as compared to those obtained from non-treated mice. We conclude that HeNe laser irradiation was able to inhibit the progress of inflammatory local reaction produced by P. brasiliensis infection and influence local cytokines production. We suggest that this treatment modality can be a useful coadjuvant tool to be combined with antifungal agents in the treatment of PCM ulcerations. The mechanisms involved in laser therapy of PCM lesions need further investigation.