WHAT ARE BACTERIA?
Bacteria, the oldest forms of life on earth, are remarkably diverse and exist in astounding numbers. It is estimated that one gram of soil can contain approximately 40 million bacterial cells whereas one milliliter of freshwater can contain 1 million bacterial cells. The total number of bacterial cells on earth is approximately 5×10^30.
Humans' relationship with bacteria is complex. Sometimes bacteria lend us a helping hand, such as helping with our digestion. In other cases, bacteria are destructive, causing diseases like pneumonia and methicillin-resistant Staphylococcus aureus (MRSA).
They can vary in shape, size, structure, and even the environments they are built for. Because bacteria come in so many types, they are found in all sorts of places from the deepest underwater caves to the food in your lunchbox.
Humans generally have anywhere from 2-5 lbs. of bacteria in their bodies.
Different types of bacteria are grouped into two categories and further classified into groups based on shape and cell wall structure.
Aerobic bacteria are species of bacteria that require oxygen for their basic survival, growth, and process of reproduction.
Anaerobic bacteria also referred to as anaerobes, are the species of bacteria which do not require oxygen for growth. There are different types of anaerobic species, including the aerotolerant anaerobes, which can survive in the presence of oxygen, and obligate anaerobes, which cannot survive in the presence of oxygen.
Bacteria are classified into five groups based on their shape such as:
Spherical (cocci): These are spherical or round. Example: streptococcus group, responsible for “strep throat.”
Comma (vibrios): These are curved-rod shaped. Example: cholera
Rod (Bacillus): These appear as rod shapes. Example: Bacillus anthracis (B. anthracis), or anthrax.
Corkscrew (spirochaetes) - Helically-coiled shaped or spiral-shaped bacteria that have a flexible cell wall and possess axial filaments for its motility. Example: leptospirosis, yaws
Spiral (spirilla): These are curved or spiral-shaped bacteria that have a rigid cell wall and utilize polar flagella for their movement. Example: Leptospirosis, Lyme disease, and syphilis are caused by bacteria of this shape.
Bacterial cells can also be classified based on their cell wall nature:
Gram-Positive bacteria contain thick cell walls. Examples: mycobacterium, corynebacterium, nocardia, rhodococcus, listeria, clostridia.
Gram-negative bacteria contain thin cell walls as compared to gram-positives. Examples: Ecoli, pseudomonas, Acetobacter.
The major difference between gram-positive and gram-negative bacteria is that gram-positive bacteria have a thick peptidoglycan layer in their cell wall while gram-negative bacteria have a thin peptidoglycan layer in their cell wall. Apart from the peptidoglycan layer, gram-negative bacteria possess an outer membrane that makes them more virulent and resistant to antibiotics. This membrane is absent in gram-positive bacteria making them comparatively less virulent and more susceptible to antibiotics. Hence, this is also a difference between gram positive and gram-negative bacteria. Furthermore, gram negative bacteria have a periplasmic space and two layers in the cell wall while gram-positive bacteria lack a periplasmic space, and they have a single layered rigid and even cell wall.
CHARACTERISTICS OF BACTERIA
Bacteria can cause different symptoms depending on the type of bacteria involved. Furthermore, bacteria can survive in any environment from extreme heat to extreme cold and even radioactive waste.
Diseases caused by bacteria include some of the most common infections in the world, as well as some of the most important human scourges, past, present, and probably future. At the same time, each of us is colonized by more bacterial cells than we have human cells in our bodies. In general, this is a peaceful and even productive (symbiotic) relationship, nonetheless, even-these well tolerated inhabitants of the human biosphere, cause disease.
Bacteria are always on you and within you. The bad bacteria cause diseases while good bacteria destroy bad bacteria and prevent diseases. In fact, your intestine has a permanent infection. However, these gut bacteria are actually immensely helpful for digestion. Many people take probiotic supplements to encourage the growth of this group of healthy bacteria. If a pro-biotic is meant to be pro-bacteria, then what do you think an anti-biotic does? Yes, an antibiotic is harmful to bacteria. Doctors prescribe antibiotics to help your immune system out when you have a bacterial infection. However, some bacteria become antibiotic-resistant and cannot be treated.
Antibiotics are usually not effective for sore throats and common colds as they are caused by viruses rather than bacteria. Taking antibiotics for such illnesses is considered more harmful than beneficial.
The study of infectious diseases is a dynamic field, in part due to the evolving nature of pathogens. A critical aspect of bacterial evolution is the acquisition of resistance to antimicrobial agents.
The discoverer of penicillin Alexander Fleming warned even as early as the 1920s about the possibility of antibiotic-resistant bacteria due to antibiotics misuse.
As the prescribing of antimicrobial therapies grows, whether they address important, controversial, or trivial indications of disease, antimicrobial resistance by pathogens and indigenous organisms continues to grow in tandem. Equally important, is an understanding of the biology, epidemiology, and mechanisms for resistance in populations of microbes that infect and colonize humans, which often provide reservoirs for resistance. Apex Physicians are at the forefront of the efforts to reduce the development of resistance.