Metabolic requirements and antibiotic susceptibility of Clostridium botulinum and Staphylococcus aureus

Microbiology

Microbes

Microbial metabolism is referred to as the manner in which microbes find their nutrients and energy that makes them live and reproduce. The paper will describe metabolic requirement for Staphylococcus aureus and Clostridium botulinum that provide them with environment that support their growth. The paper also summarizes mechanism of action by which drug inhibits the growth of Pseudomonas aeruginosa.

Staphylococcus aureus

Staphylococcus aureus is as facultative anaerobic gram-positive cocci that is able to occur in irregular, in pairs or in single cluster. It tends to be catalase/coagulase positive, non-spore forming and nonmotile. The real colonies have a color that ranges from yellow to golden yellow, slightly raised, smooth as well as hemolytic on 5% sheep blood agar. Nevertheless, most of the strains may as well look non-hemolytic and dirty white.

Generally staphylococcus aureus is known to find their breading environment on the skin as well as mucous membranes that belongs to warm-blooded animals especially in humans being. A perfect habitat for staphylococcus aureus colonies tend to be in the nasal membrane simply because this place is usually warm and moist. It has been estimated that among healthy human adults 10-40% have been infected by staphylococcus aureus that grows in their noses. Not only does staphylococcus aureus live within humans, there are other habitats that they can be found such as in decaying matter, water and on any surface, (U.S. Department of Health & Human Services, 2013). Staphylococcus aureus breed well within a wide temperature range of about 15°C -- 45°C (60 -- 113 F). It is capable of existing in a dominant state for several years in case there is an unfavorable growth condition of nutrients or temperature supply. This bacterium waits until the conditions become more favorable. The reason that makes staphylococcus aureus resilient is the fact that it has an extremely thick cell wall than other bacteria cell wall. Such thickness gives the bacteria opportunity to have a higher internal pressure existence. Since it has thick walls as well as high internal pressure, it becomes not easy for antibacterial drugs to access them.

Clostridium botulinum

This is a bacterium causing botulism in form of Gram-positive organisms, they are characterized by their somehow anaerobic rods, motile, and curved nature which works by producing heat-resistant spores. Due to the fact that its spores are highly resistant to various environmental stresses like high acid and heat among others, they are possibly activated when they are in anaerobic, low acid (Ph higher than 4.6), an environment with high moisture having temperatures that ranges from 3°C to 43°C (38 F. 110 F). The existing spores form a base where bacteria can survive under adverse environmental conditions and later after the condition has become favorable then they germinate.

The nature of clostridium botulinum is ubiquitous and it usually bread in water or soil. Spores and the bacteria that are found in them never cause disease, however since it has botulinum toxic that is produced it causes botulism which is a dangerous paralytic condition that sometimes can cause death, (Keith R. Schneider, 2012). Clostridium botulinum exists in seven strains depending on the antigenicity differences of the toxins. All of them are characterized by their distinct capability of producing a protein haemotoxin, enterotoxin, or neurotoxin. The ones that causes botulism in human are type A, B, E, and F, while the ones that causes botulism in birds and animals are type C and D.

Clostridium botulinum has some of its main limiting growth factors such as pH < 4.6, extreme temperature, competing micro-organisms, food preservatives, and low water activity. Its strains may be psychotrophic and mesophilic at the same time, having a growth that ranges from 3°C to 43°C (38 F. To 110 F). Meaning that there is possibility of strains growing at room temperatures and also at normal refrigeration as well as temperatures that are high, (Centers for Disease Control and Prevention, 1998). Even though many of the bacteria finds a low pH unfavorable for them to survive, some of the proteins for example in beef and soy have developed a protective agents that makes them capable of growing at pH < 4.5. Growth of Clostridium botulinum is inhibited by low water activity, for instance food which has high sugar or salt and dehydrated foods cannot support its growth.

Pseudomonas aeruginosa