Actinomycetes are known to be major producers of antibiotics and other metabolites. Watve et. al. (2001) estimated that more than 105 antibiotics are produced by Streptomyces and only a small portion (3%) of these antibiotics have been discovered thus far. Antibiotics are the third largest pharmaceutical drug market segment with more than US$25.7 billion global sales in 2004 (vom Nussbaum, 2006).

The search for new antibiotics from microbes continue due to a) development of resistant pathogens, b) evolution of new diseases, c) the existence of naturally resistant bacteria, and d) the toxicity of some of the current compounds.

Antibiotic resistance is a major problem in the management of infections caused by pathogens that are resistant to multiple classes of antibiotics. Resistance could spread at interspecies and intergeneric levels when gene encoding resistance mechanism are transferred between pathogens.

The occurrence of various antibiotic-resistant strains of Staphylococcus aureus, historically known as MRSA is a global problem because of its virulence and high transmissibility, and because of limited treatment options for infected patients. Local investigators have reported the presence of MRSA in the Philippines. Ontengco et. al., (2004) showed that of 373 S. aureus isolated from in-patients of three tertiary hospitals from years 1999-2003, 18.2% (68) were comfirmed MRSA by oxacillin agar test, cefoxitin disk breakpoints, and the heterogenous expression with oxacillin disk. On the other hand, nosocomial gram-negative pathogens like Pseudomonas and members of the family Enterobacteriaceae are causing epidemics and outbreaks. They are also resistant to multiple antibiotics. When recovered from patients of the neonatal intensive care unit (NICU), they are associated with increase mortality rates, prolonged hospital stay of survivors and increased healthcare cost.