Antimicrobial producing properties of microorganisms isolated from soil, sea and the Kakum river

The lives of both humans and animals are threatened by so many kinds of infectious diseases. An infectious disease is a disease that may be caused by a virus, bacteria, fungi, protozoa or helminth. Examples of infectious diseases include tuberculosis (TB; caused by Mycobacterium tuberculosis), cholera (caused by Vibrio cholerae), candidiasis (caused by species of Candida), malaria (caused by Plasmodium species), Trypanosomiasis (caused by Trypanosoma species), schistosomiasis (caused by Schistosoma species). Examples of viral infections also include Ebola, hepatitis and HIV/AIDS (Lerner and Lerner, 2008). For the past two decades, there has been emergence of new infections and also reemergence of old infections in both developed and developing countries (Madigan et al., 2015; Morse, 1995; Talaro and Talaro, 2001). It was hypothesized in 2003 that 8.8 million people worldwide were living with TB, and laboratory test(s) showed that 3.9 million of people were living with the disease when the hypothesis was tested (Godreuil et al., 2007). Again, in 2012, the World Health Organization pointed out that a total of 8.3 million people developed TB out of which 1.3 million infected individuals died (WHO, 2014). It was also estimated that there will be 450,000 new cases of multidrug – resistant TB infections worldwide (WHO, 2014). Fortunately, most of these microbial infections have been controlled immensely by the application of antimicrobial agents – a process known as chemotherapy. An antimicrobial 2 agent is defined as an agent which in small concentration can kill or inhibit the growth of microorganisms (Russell, 2004). Though, these agents are produced naturally by microorganisms (Singh et al., 2012), there are also synthetic forms. A good number of antimicrobial agents have been isolated from microorganisms belonging to the phylum Actinobacteria where species of Streptomycetes are the dominant antimicrobial producers (Hirsch et al., 1983; Nike et al., 2013; Kumari et al., 2013; Sarkar et al., 2014). About 70% of natural antimicrobial agents have been isolated from actinomycetes, and the remaining 30% are products of non – actinomycete bacteria such as Pseudomonas and Bacillus species, and filamentous fungi (Singh et al., 2012; Hays et al., 1945). Actinomycin, streptomycin, tetracycline, chloramphenicol, vancomycin and gentamycin are examples of antimicrobial agents obtained from Actinomycetes (Sharma, 2014; Abdulkadir and Waliyu, 2012). Some species of Bacillus also produce antimicrobial agents such as bacitracin, surfactins, inturinics, pumulin, bacilysin and gramicidin (Abdulkadir and Waliyu, 2012). Over 12,000 antimicrobial agents have been isolated from microorganisms but only few are being used today in the treatment and management of infections (Singh et al., 2012). The high cost of production of some antimicrobial agents have resulted in fewer numbers of such agents on the market (Naine et al., 2014; Brumfitt and Hamilton-Miller, 1988). Exposure and improper use of the available antimicrobial agents have resulted in different forms of antimicrobial resistance and this has contributed to the difficulty in the treatment of infectious diseases caused by these resistant strains of pathogenic organisms (Costelloe et al., 2010; Houben et al., 1999). One mechanism of antimicrobial resistance is biofilms formed by microorganisms (Drenkard, 2003). In microbial biofilm formation.

Source: KNUST