Antimicrobial resistance (AMR) directly kills about 1,600 people each year in Australia. [1] This is a currently serious threat to both humans and animals in the country. [2] Antimicrobial resistance occurs when a microorganism (i.e. fungi, bacteria, viruses) evolves and gains the ability to become more resistant or completely resistant to the medicine that was previously used to treat it. [3] Drug-resistant bacteria are increasingly difficult to treat, requiring replacement or higher-dose drugs that may be more expensive or more toxic. [4] Resistance can develop through one of the three mechanisms: natural resistant ability in some types of microorganisms, a mutation in genes or receiving the resistance from another species. [5] Antibodies appear naturally due to random mutations, or more often after gradual accumulation over time, and because of abuse of antibiotics. [6] Multidrug-resistance, or MDR, are the microorganisms that are resistant to many types of antimicrobials. [3] "Superbugs" is the term also used for multidrug-resistant microbes, or totally drug-resistant (TDR). [4] [3]
In October 2017, the Australian Government reported that the Australians were over-using antibiotic. [7] In 2015, Australian doctors dispensed over 30 million antimicrobial prescriptions via the Pharmaceutical Benefits Scheme (PBS) or Repatriation PBS. [7] When antimicrobials are used to kill microbes, a small group of microbes survive. [8] Some, gaining the resistance gene, may still survive and are only weakened. As more antimicrobials of the same type taken, the surviving microorganisms start to gain resistance to it. The misuse of antimicrobials creates a natural selection condition under which those surviving ones have a chance to reproduce and the drug-resistant bacteria are more common. [6] When the recent dose does not affect anymore, it will have to require a higher dose to kill microbes. Over time, the bacteria will become resistant with that particular antimicrobial medication. [6] [8]
Genetic Mutation is known as one of the natural causes of Antimicrobial Resistance. [8] Microorganisms can reproduce rapidly by replicating itself every period of time, which allowing them the ability to evolve and adapt to the changes in the environment. Every time a microbe goes into the reproduction process, there is a risk to have random errors in its genetic replication process, called mutation. [10] These mutations can either positively or negatively affect the microbe itself. The genetic mutation could give the microorganism the ability to adapt, become resistant to the antimicrobials which are being used to kill treat the disease. [8] [10] The drug-resistant bacteria reproduced and the gene of resistance become dominant and the population becomes resistance to the antimicrobials. [10]
Horizontal Gene Transfer is a process in which the microorganisms are able to share their gene with each other. [8] [11] The known result for gene transfer is genetic variation and it could be a serious problem when they are also able to transfer the drug-resistance genes to each other. [8] Bacteria are able to share genetic information with each other via three mechanisms: conjugation, transduction and transformation. [12]
The effect of antimicrobials on microbes is disrupting the internal structures of the bacteria to stops them from reproducing or to kill them. [12] [13] The microbes can gain resistance to the drugs by changing the structures to prevent their actions. [12]
Microorganisms can resist antimicrobials by preventing the drug from reaching its target. [12] Microbes can push away the antimicrobials out of the cell's body by creating pumps placed in the membrane, called efflux pumps. [12] These efflux pumps transport nutrient molecules in and out the cell and can be used to pump the antimicrobials out of the microbe. [13] Another mechanism to withstand the action of antimicrobials is reducing the cell membrane's permeability, preventing the drug get through the cell membrane. [12] The enzyme, β-lactamase, in some drug-resistant bacteria, has the ability to break down the active component in the penicillins. [12] [13] Bacteria can sometimes complicatedly modify the structure and components of the antimicrobials by producing enzymes so the antimicrobials can no longer interact with the microbe cell. [12]
A microbe can modify its target by changing the composition or the structure, adding different chemical components to prevent the drug from reaching its target. [12] Some bacteria can produce an alternative protein which can replace the original proteins inhibited by the antibiotic. [12] Some bacteria can also reprogram its target by forming a different variant of a needed structure so the antibiotics cannot have action on it. [12]
The Australian Department of Health and Department of Agriculture and Water Resources had worked together and released the first National Antimicrobial Resistance Strategy 2015-2019 (the Strategy) in June 2015. [14] The Australian Government proposed the main strategies to respond to the threat of antimicrobial resistance, minimise its rapid development and control its spread. [15] The strategy of the Australian Government on AMR aligned with the World Health Organisation (WHO) Global Action Plan and provided the objectives for Australia's nation across the human health, animal health, agriculture and food sectors:
An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention of such infections. They may either kill or inhibit the growth of bacteria. A limited number of antibiotics also possess antiprotozoal activity. Antibiotics are not effective against viruses such as the ones which cause the common cold or influenza. Drugs which inhibit growth of viruses are termed antiviral drugs or antivirals. Antibiotics are also not effective against fungi. Drugs which inhibit growth of fungi are called antifungal drugs.
Antimicrobial resistance occurs when microbes evolve mechanisms that protect them from the effects of antimicrobials. All classes of microbes can evolve resistance to the point that one or more drugs used to fight them are no longer effective. Fungi evolve antifungal resistance, viruses evolve antiviral resistance, protozoa evolve antiprotozoal resistance, and bacteria evolve antibiotic resistance. Together all of these come under the umbrella of antimicrobial resistance.
Drug resistance is the reduction in effectiveness of a medication such as an antimicrobial or an antineoplastic in treating a disease or condition. The term is used in the context of resistance that pathogens or cancers have "acquired", that is, resistance has evolved. Antimicrobial resistance and antineoplastic resistance challenge clinical care and drive research. When an organism is resistant to more than one drug, it is said to be multidrug-resistant.
Klebsiella pneumoniae is a Gram-negative, non-motile, encapsulated, lactose-fermenting, facultative anaerobic, rod-shaped bacterium. It appears as a mucoid lactose fermenter on MacConkey agar.
Colistin, also known as polymyxin E, is an antibiotic medication used as a last-resort treatment for multidrug-resistant Gram-negative infections including pneumonia. These may involve bacteria such as Pseudomonas aeruginosa, Klebsiella pneumoniae, or Acinetobacter. It comes in two forms: colistimethate sodium can be injected into a vein, injected into a muscle, or inhaled, and colistin sulfate is mainly applied to the skin or taken by mouth. Colistimethate sodium is a prodrug; it is produced by the reaction of colistin with formaldehyde and sodium bisulfite, which leads to the addition of a sulfomethyl group to the primary amines of colistin. Colistimethate sodium is less toxic than colistin when administered parenterally. In aqueous solutions, it undergoes hydrolysis to form a complex mixture of partially sulfomethylated derivatives, as well as colistin. Resistance to colistin began to appear as of 2015.
An antimicrobial is an agent that kills microorganisms (microbicide) or stops their growth. Antimicrobial medicines can be grouped according to the microorganisms they act primarily against. For example, antibiotics are used against bacteria, and antifungals are used against fungi. They can also be classified according to their function. The use of antimicrobial medicines to treat infection is known as antimicrobial chemotherapy, while the use of antimicrobial medicines to prevent infection is known as antimicrobial prophylaxis.
Vancomycin-resistant Staphylococcus aureus (VRSA) are strains of Staphylococcus aureus that have acquired resistance to the glycopeptide antibiotic vancomycin. Bacteria can acquire resistant genes either by random mutation or through the transfer of DNA from one bacterium to another. Resistance genes interfere with the normal antibiotic function and allow bacteria to grow in the presence of the antibiotic. Resistance in VRSA is conferred by the plasmid-mediated vanA gene and operon. Although VRSA infections are uncommon, VRSA is often resistant to other types of antibiotics and a potential threat to public health because treatment options are limited. VRSA is resistant to many of the standard drugs used to treat S. aureus infections. Furthermore, resistance can be transferred from one bacterium to another.
Multiple drug resistance (MDR), multidrug resistance or multiresistance is antimicrobial resistance shown by a species of microorganism to at least one antimicrobial drug in three or more antimicrobial categories. Antimicrobial categories are classifications of antimicrobial agents based on their mode of action and specific to target organisms. The MDR types most threatening to public health are MDR bacteria that resist multiple antibiotics; other types include MDR viruses, parasites.
Tetracyclines are a group of broad-spectrum antibiotic compounds that have a common basic structure and are either isolated directly from several species of Streptomyces bacteria or produced semi-synthetically from those isolated compounds. Tetracycline molecules comprise a linear fused tetracyclic nucleus to which a variety of functional groups are attached. Tetracyclines are named after their four ("tetra-") hydrocarbon rings ("-cycl-") derivation ("-ine"). They are defined as a subclass of polyketides, having an octahydrotetracene-2-carboxamide skeleton and are known as derivatives of polycyclic naphthacene carboxamide. While all tetracyclines have a common structure, they differ from each other by the presence of chloro, methyl, and hydroxyl groups. These modifications do not change their broad antibacterial activity, but do affect pharmacological properties such as half-life and binding to proteins in serum.
Medical microbiology, the large subset of microbiology that is applied to medicine, is a branch of medical science concerned with the prevention, diagnosis and treatment of infectious diseases. In addition, this field of science studies various clinical applications of microbes for the improvement of health. There are four kinds of microorganisms that cause infectious disease: bacteria, fungi, parasites and viruses, and one type of infectious protein called prion.
Enterococcus faecium is a Gram-positive, gamma-hemolytic or non-hemolytic bacterium in the genus Enterococcus. It can be commensal in the gastrointestinal tract of humans and animals, but it may also be pathogenic, causing diseases such as neonatal meningitis or endocarditis.
Antibiotic misuse, sometimes called antibiotic abuse or antibiotic overuse, refers to the misuse or overuse of antibiotics, with potentially serious effects on health. It is a contributing factor to the development of antibiotic resistance, including the creation of multidrug-resistant bacteria, informally called "super bugs": relatively harmless bacteria can develop resistance to multiple antibiotics and cause life-threatening infections.
The host-pathogen interaction is defined as how microbes or viruses sustain themselves within host organisms on a molecular, cellular, organismal or population level. This term is most commonly used to refer to disease-causing microorganisms although they may not cause illness in all hosts. Because of this, the definition has been expanded to how known pathogens survive within their host, whether they cause disease or not.
Antibiotic use in livestock is the use of antibiotics for any purpose in the husbandry of livestock, which includes treatment when ill (therapeutic), treatment of a group of animals when at least one is diagnosed with clinical infection (metaphylaxis), and preventative treatment (prophylaxis). Antibiotics are an important tool to treat animal as well as human disease, safeguard animal health and welfare, and support food safety. However, used irresponsibly, this may lead to antibiotic resistance which may impact human, animal and environmental health.
ESKAPE is an acronym comprising the scientific names of six highly virulent and antibiotic resistant bacterial pathogens including: Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp. The acronym is sometimes extended to ESKAPEE to include Escherichia coli. This group of Gram-positive and Gram-negative bacteria can evade or 'escape' commonly used antibiotics due to their increasing multi-drug resistance (MDR). As a result, throughout the world, they are the major cause of life-threatening nosocomial or hospital-acquired infections in immunocompromised and critically ill patients who are most at risk. P. aeruginosa and S. aureus are some of the most ubiquitous pathogens in biofilms found in healthcare. P. aeruginosa is a Gram-negative, rod-shaped bacterium, commonly found in the gut flora, soil, and water that can be spread directly or indirectly to patients in healthcare settings. The pathogen can also be spread in other locations through contamination, including surfaces, equipment, and hands. The opportunistic pathogen can cause hospitalized patients to have infections in the lungs, blood, urinary tract, and in other body regions after surgery. S. aureus is a Gram-positive, cocci-shaped bacterium, residing in the environment and on the skin and nose of many healthy individuals. The bacterium can cause skin and bone infections, pneumonia, and other types of potentially serious infections if it enters the body. S. aureus has also gained resistance to many antibiotic treatments, making healing difficult. Because of natural and unnatural selective pressures and factors, antibiotic resistance in bacteria usually emerges through genetic mutation or acquires antibiotic-resistant genes (ARGs) through horizontal gene transfer - a genetic exchange process by which antibiotic resistance can spread.
Corynebacterium striatum is a bacterium that is a member of the Corynebacterium genus. It is classified as non-diphtheritic. The bacterium is a gram-positive prokaryote that assumes a 'club-like' morphology, more formally known as a corynebacteria structure. It is non-lipophilic and undergoes aerobic respiration and is also a facultative anaerobe it is catalase negative and oxidase positive glucose and sucrose fermenter.
The antimicrobial spectrum of an antibiotic means the range of microorganisms it can kill or inhibit. Antibiotics can be divided into broad-spectrum antibiotics, extended-spectrum antibiotics and narrow-spectrum antibiotics based on their spectrum of activity. Detailedly, broad-spectrum antibiotics can kill or inhibit a wide range of microorganisms; extended-spectrum antibiotic can kill or inhibit Gram positive bacteria and some Gram negative bacteria; narrow-spectrum antibiotic can only kill or inhibit limited species of bacteria.
The Society of Infectious Diseases Pharmacists (SIDP) is a non-profit organization comprising pharmacists and other allied health professionals specializing in infectious diseases and antimicrobial stewardship. According to the Board of Pharmaceutical Specialties, clinical pharmacists specializing in infectious diseases are trained in microbiology and pharmacology to develop, implement, and monitor drug regimens. These regimens incorporate the pharmacodynamics and pharmacokinetics of antimicrobials for patients.
Multidrug-resistant bacteria are bacteria that are resistant to three or more classes of antimicrobial drugs. MDR bacteria have seen an increase in prevalence in recent years and pose serious risks to public health. MDR bacteria can be broken into 3 main categories: Gram-positive, Gram-negative, and other (acid-stain). These bacteria employ various adaptations to avoid or mitigate the damage done by antimicrobials. With increased access to modern medicine there has been a sharp increase in the amount of antibiotics consumed. Given the abundant use of antibiotics there has been a considerable increase in the evolution of antimicrobial resistance factors, now outpacing the development of new antibiotics.