Medical Perspectives | Infectious Diseases, Others

May 11, 2021

Doctor Gwen Y. Reyes-Amurao, M.D.

Antibiotics are medications used to treat infections or diseases caused by bacteria. Since the discovery of Penicillin by Alexander Fleming, these anti-bacterials have saved millions of lives and continue to do so until this very day.


How They Work

Antibiotics work by killing or destroying bacteria, preventing them from spreading and causing further harm. Bacterial growth is prevented by these medications through various mechanisms that include disruption of bacterial membrane structure, inhibition or regulation of enzymes involved in bacterial cell wall biosynthesis, nucleic acid metabolism and protein synthesis.


Typically, a person is able to fight off infection through his or her natural defenses and complex immune system. However, once these are weakened, infection may ensue and producesigns and symptoms associated with infectious disease. Other factors that predispose a person to infection include the presence of an underlying medical condition, extremes of age, and malnutrition. Although some may be more likely to acquire an infection, anyone can catch it.


Principles in Antibiotic Treatment

Antibiotic treatment plays a major role in the maintenance of health and prevention of disease complications worldwide. To ensure their proper use, the Department of Health (DOH) through the efforts of the National Antibiotics Guidelines Committee (NAGCOM) has come up with a reference that optimizes antimicrobial use and help improve the quality of patient care and safety. Through these guidelines and asound clinical judgement, health practitioners should be able to address common infectious diseases seen among adults and children.Furthermore, they should address problems associated with antibiotic use and misuse leading to resistance.


In general, antibiotic use is determined mainly by the type of bacteria causing the infectious disease.It is affected by certain host or patient-related factors as well as microbiologic components. When choosing the type of anti-infective, the site and severity of infection are often the primary considerations.Localized signs of infection withpresence of pus or devitalized tissue require stronger antibiotics.


Bacterial load, virulence, regrowth and susceptibility patterns of the pathogen are also important determinants in choosing suitable anti-infectives for patients. At the other end of the spectrum, certain patient-related factors influence the efficacy and even the toxicity of the antimicrobial to be used. Age, genetic abnormalities, and liver or kidney problems all determine which type of antibiotic should or should notbe given to the patient. When a person is immunocompromised and in the presence of co-morbid illnesses, certain antibiotics may also be preferred over others.


Once these factors are carefully considered, antibiotics should then be prescribed and administered correctly. Proper dosage, interval, frequency, route of administration, and duration of treatment are prime considerations. According to the National Antibiotic Guidelines (NAG), health practitioners must first formulate a diagnosis which may require confirmation through laboratory tests and procedures. Once a bacterialdiagnosis is reached, antibiotic therapy should commence at the soonest possible timebeing supplemented by non-pharmacologic therapy.


Factors Leading to Resistance

With a correct diagnosis and prescription of antimicrobial medication, the individual suffering from the infection should be well on his way to recovery. Unfortunately, infections have still been documented to account for a large number of mortalities across the globe, according to a study published in the Journal of Anesthesiology and Clinical Pharmacology. Although this may be attributed to the emergence of new strains of infectious agents, the concept of antimicrobial resistance seems to play a significant role in the development of infections leading to mortalities worldwide.


Through time, bacteria have become more developed and more intelligentwhen it comes to recognition of antibiotics.Bacteria have produced different biochemical resistance mechanisms such as antibiotic inactivation, target modification, altered permeability to antibiotics, and bypassof certain metabolic pathways.


Aside from bacterial adaptability to certain antibiotics, most bacteria have become resistant to due to antibiotic misuse and abuse. With the advent of technology and the handy Doctor Google, more people have been self-prescribing antibiotics. This added further to misuse and abuse. Most of the time, these individuals take antibiotics even when it is not needed, like in the case of viral infections.


Patients believe that with the antibiotics, they achieve faster relief from the signs and symptoms of an illness, when in fact, viral illness often resolves after a few days due to its self-limiting ability. Once antibiotics are introduced into the body, bacteria exposed to ithave the ability to adapt and protect itself from it, thereby leading to resistance.


Besides self-medicating, other common reasons for misuse and abuse of antibiotics include empiric or experimental use on fever of unknown origin, inappropriate antibiotic combination, lack of knowledge on appropriate antibiotic information including its indications, dosage and cost, over-the-counter purchases of antibiotics, and the use of antimicrobials as growth promoters in farm animals and agriculture.Antimicrobial resistance in poultry and livestock affects consumers when these products are introduced in the body.


The Burden of Antimicrobial Resistance

Antimicrobial resistance is now a global concern, and affects millions all over the world. It threatens the effective prevention and treatment of a wide range of infections caused not only by bacteriabut by parasites and fungi as well.


The World Health Organization (WHO) has developed a global action plan on Antimicrobial Resistance (AMR) to set up a mechanism to test and evaluate the standard for surveillance of resistance to antibiotics. Results of such surveillance programs have revealed an alarming increase in incidence of multi-drug resistant and extensively drug-resistant tuberculosis (MDR-TB and XDR-TB) in 92 countries worldwide.


High incidence of antibiotic resistance in bacteria that causes urinary tract infections, pneumonia, and bloodstream infections have also been observed in various regions around the world, while MRSA or multi-drug resistant Staphylococcus aureus and multidrug-resistant gram-negative bacteria are now commonly found in hospital-acquired infections.


The WHO recognizes the evolution of resistant strains as a natural phenomenon wherein microorganisms replicate themselves mistakenly or when resistant traits are transferred from abacterium to another. This, together with poor infection control technique and sanitary conditions, all encourage the spread of antimicrobial resistance in one’s surroundings and have added to the global burden of resistance.


Effects of Antimicrobial Resistance

Infections caused by resistant microorganisms often fail to respond to the standard treatment, resulting to prolonged illness, increased cost of therapy, and increased length of hospital stay. In cases of prolonged illness, the patient naturally remains infectious for a longer period of time, increasing the likelihood of spreading resistant micro-organisms to the people around them.In addition, chances of recovery or recuperation can also be decreased.


 The cost of therapy lies not only on the longer use of antimicrobial agents, but also on the utilization of more complicated and more expensive forms of treatment. As the duration of illness lengthens, health care costs naturally increase leading to greater economic and financial burden on the patient and his family. Needless to say, antimicrobial resistance can no longer be classified as an individual concern since the entire community will always be affected.


Management and Prevention of Antimicrobial Resistance

Knowing the causes and effects of antimicrobial resistance is not enough to address it. With the following recommendations from the World Health Organization, the goal is to decrease incidence of antimicrobial resistance and completely eradicate it and improve health care situations worldwide.


Identifying the Frequency of Resistance

Because of antimicrobial resistance surveillance programs now present in over 30 countries all over the world, locating, facilitating, and giving appropriate treatment choices are now easier to conduct. Such programs allow the different health departments to identify new pathogens for which proper control and prevention can be achieved. The presence of the Alliance for the Prudent Use of Antibiotics or APUA has helped in the global surveillance of AMR. Through its programs, global defenses against infectious diseases are strengthened by providing access to effective treatment and promoting antibiotic use to contain drug resistance.


Isolating Hospitalized Individuals with Known Resistant Strains of Bacteria

By isolating individuals with resistant bacterial strains, the spread of infection is kept to a minimum. Moreover, areas confined specifically for these patients can be monitored more closely, with any other form of illness arising addressed immediately.


Introducing New Treatment Approaches

According to studies, the appropriate and prudent use of antibiotics not only helps reverse high resistance incidence, but also curbs the appearance of resistance to newer strains or microbial agents. Better compliance to antibiotic intake has proven to be effective not only in treating disease but also in preventing emergence of resistance.


Discontinuing Use of The Same Antibiotics in Areas Where Drug Resistance Is Endemic

The emergence or development of novel antibiotics can markedly reduce AMR because of its ability to evade current resistance mechanisms.


One cannot overemphasize the role of antibiotics in the treatment of infectious diseases. Despite the increasing frequency of antimicrobial resistance, the need for vigilance plays a much greater role now more than ever. The Philippines and the rest of the world should double its efforts in preserving the efficacy of the microbial agents available and expand the search for new lines of therapy that can help address the problem of antimicrobial resistance.



  • National Antibiotic Guidelines 2017
  • Kapoor G, Saigal S, Elongavan A. Action and Resistance Mechanisms of Antibiotics: A Guide for Clinicians.Journal of Anesthesiology and Clinical Pharmacology. 2017; 33(3):300-305. doi:10.4103/joacp.JOACP_349_15, PMCID: PMC5672523, PMID: 29109626
  • Lathers CM. Clinical Pharmacology of Antimicrobial Use in Humans and Animals.Journal of Clinical Pharmacology. 2002;42(6):587-600. Accessed through
  • Antimicrobial Resistance. Philippine Council for Health Research and Development.

National Antibiotic Guidelines Committee

Pharmaceutical Division, Department of Health

1100ISBN - 978-621-95675-1-0

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