Investigation on the Effectiveness of Antibiotics in the Modern World

Rationale

The claim, ‘Antibiotics have had their day’, encompasses numerous elements that require further investigation to obtain a logical conclusion to the accuracy of the claim. Antibiotics represent the drugs used in medicinal practice to treat bacterial infections. As such, they perform to attack bacteria through the inhibition of bacterial microorganism’s growth in an attempt to destroy the bacterial cells (Shiel, 2018). There are several groups of antibacterial drugs which aim to destroy bacterial infections through different methods, one of which, includes penicillin. Penicillin is the most commonly used group of antibacterial drugs, which is derived from a common mould grown on bread and fruit (Newman, 2019).

Many argue that the commonality and accessibility of antibiotics in modern-day society has resulted in the misuse of the drug, where patients are often incorrectly prescribed antibiotics for illnesses where the presence of these drugs are inefficient to treatment, such as viral infections. As antibiotics perform to destroy bacterium in the body, each time these drugs are unnecessarily consumed, residual bacterium mutates to modify genetic material to develop antibiotic resistance (World Health Organisation, 2018). As a result of this, an antibiotic-resistant bacterium such as the common methicillin-resistant Staphylococcus aureus (MRSA) is difficult to treat.

Furthermore, the research question to be investigated is as follows:

Does the antibiotic, methicillin prove ineffective in treating Staphylococcus aureus infections in current times compared to its first introduction in 1960?

Background

Methicillin is a common antibiotic, formerly used in the treatment of infections within the bacterial genus, Staphylococcus. The antibiotic is a semi-synthetic derivative of penicillin. As such, it belongs to the β-lactam class, which contains a beta-lactam ring in its molecular structure and is vital to the antimicrobial activity of the drug (Ophardt, 2019). Much like other penicillins, the beta-lactam ring present in methicillin performs its bactericidal effects through the inhibition of synthesis of the peptidoglycan layer in the cell wall.

Thus, bacteria are attacked when the methicillin binds to specific penicillin-binding proteins which prevent the cross-linkage of peptidoglycans (U.S National Library of Medicine, 2019). Consequently, bacterial lysis occurs, where the methicillin is successful in destroying the bacteria. Methicillin was first introduced as a medicinal drug in 1959 for the treatment of penicillin-resistant S. aureus (National Institute of Allergy and Infectious Diseases, 2016). As such, the introduction of the antibiotic proved to be a successful discovery, however, due to its overuse and misuse, bacteria soon grew resistant to this drug too.

Staphylococcus aureus signifies the colonised bacteria which is found in normal human flora, located on the skin and mucous membranes and is generally harmless to humans. However, occasionally, the bacteria can enter the body through open wounds and when contacted with the bloodstream or internal tissues, bacterial infections can be caused. These infections most commonly occur as boils and impetigo, however, can be more severe such as septicaemia and pneumonia (Queensland Government, 2017). Within the numerous strains of S. aureus, lies a specific strain of bacteria which is resistant to the antibiotic, methicillin.

This is called methicillin-resistant Staphylococcus aureus (MRSA). S. aureus infections are commonly treated with antibiotics; however, the process of natural bacterial evolution has enabled some strains (like MRSA) to become resistant to medicinal drugs designed to fight these infections. Methicillin-resistant strains were first discovered in 1961 and are now resistant to the entire penicillin class, including amoxicillin, penicillin and oxacillin (Nichols, 2017). Consequently, strains of the bacteria that are resistant to antibiotics are difficult to treat and easily spread through direct contact, hence, the treatment of S. aureus with methicillin is now considered aimless. Penicillin resistance to S. aureus is reliant on the synthesis of β-lactamase, whilst methicillin resistance occurs due to the development of the mecA gene, which encodes a methicillin-resistant penicillin-binding protein (Enright, 2002). This gene is transported on a mobile genetic element called the staphylococcal cassette chromosome (SCC).

Evidence

Due to the increasing accessibility and overuse of common antibiotics, MRSA cases have increased over the years. As such, a study by the Healthcare Cost and Utilization Project (HCUP) in 2007 investigated the trend in MRSA infections from 1993 to 2005. Figure 1 is representative of the growth of MRSA infections over these 13 years. From this, it was found that about 368 600 cases of MRSA in U.S hospitals were reported in 2005, that is a 30% increase from 2004’s cases and therefore, more than tripled the figures from 2000. As such, when compared to 1995, this figure had increased by almost ten times, with the average number of cases coming to less than 2 000 in 1993 (Elixhauser, 2007).

MRSA infections are classified into two originator groups; community-acquired (CA-MRSA) and healthcare-associated (HA-MRSA). As such, CA-MRSA infections generally evolve from endemic methicillin-susceptible S. aureus strains, whilst HA-MSRA is classed as nosocomial infections (LabCE, 2019). Furthermore, the Infectious Disease Society of America (IDSA) conducted an investigation in 2006, on the evolution of antimicrobial-resistant S. aureus as a cause of healthcare-associated and community-acquired.

When, in the 1940s, S. aureus was susceptible to penicillin, the bacteria quickly acquisition to produce a β-lactamase (penicillinase) which was able to deactivate the natural penicillins and the aminopenicillins (McDonald, 2006). As such, the healthcare-associated strain developed resistance much earlier than that of the community-acquired strain. A similar origination pattern is evident in the MRSA, where the development of HA-MRSA is significantly earlier than CA-MRSA. Research suggests that this is due to the differences in strain genotypes, where “HA-MRSA strains mostly contain SCCmec types I, II and III; associated with resistance to both β-lactam antibiotics and multiple other drug classes. CA-MRSA, however, contains SCCmec types IV and V, which function as resistant to only β-lactam antibiotics” (Bell, 2007).

Even in 2000, Figure 2 displays Penicillinase-producing S. aureus to have a higher resistance percentage than that of MRSA. This is likely to occur due to the longer prevalence of penicillin in the medicinal industry; hence, giving bacteria a longer time to manipulate DNA into developing resistance to the antibiotic. As such, the introduction of another antibiotic to fight S. aureus would predictably have higher effectiveness in its function before bacteria can recognise and manipulate itself into developing resistance.

Due to the increasing resistance to S. aureus infections worldwide, treatment is difficult to execute. However, preventative measures have proven highly effective in the control of MRSA. Figure 3, therefore, illustrates the high prevalence of MRSA globally; highlighting areas of highest prevalence (USA) and areas of least prevalence (the Netherlands and Canada). Upon further research on the Netherlands and Canada’s preventative measures, it was found both countries enforce two major policies that control the spread of MRSA. As such, a presence of a strict ‘search and destroy’ policy is enforced, where patients with MRSA symptoms are immediately isolated until screening cultures for MRSA suggest the patient does not carry an S. aureus infection (Amin, 2019). Perhaps the more effective policy, however, is the restrictive nature of prescribing medicinal drugs.

Furthermore, in the Netherlands, the defined daily dosage (DDD) used per 1000 people per day is on average, 10 (Patented Medicine Prices Review Board, 2010). Comparably, this figure exists as 36.6 for France, a country where MRSA prevalence is much higher. In the ‘Canadian Antimicrobial Resistance Surveillance System’ (CARSS) 2018 executive summary, it was evident that the through Canada’s antimicrobial restrictions, the rate of HA-MRSA infections decreased by 6% in 2017 from 2012. Furthermore, for the first time since 2013, a slight decrease in HA-MRSA bloodstream infections were evident in paediatric hospitals. It is believed that these preventative measures have aided in the decrease of overall MRSA mortality rates from 22% (in 2012) to 16% (in 2017) (Government of Canada, 2019). Moreover, figure 3 supports and links these preventative measures in its representation of MRSA prevalence globally.

Quality of Evidence

The statement, “HA-MRSA strains mostly contain SCCmec types I, II and III; associated with resistance to both β-lactam antibiotics and multiple other drug classes. CA-MRSA, however, contain SCCmec types IV and V, which function as resistant to only β-lactam antibiotics” was asserted by Edward A. Bell, a professor of clinical sciences at Drake University College of Pharmacy, Bland Children’s Hospital, in Iowa. Additionally, he is recognised as a member of the Infectious ‘Diseases in Children’ editorial board. The source being derived from this author is indicative of credibility, whilst also being supported and corroborated with by various other sources.

In collating information on the numerous aspects of the research question to assist in developing a conclusion on MRSA growth over time, a range of different sources were collaborated. Each source was carefully understood to ensure all information corroborated with each other to assess the credibility of the information being provided. Whilst, most information corroborated with each other, retracting more information on more recent data would increase the validity of this investigation further.

Figures 1 and 2 were both derived from credible medicinal journals, however, provided data from 2007. Whilst this information proved useful in this investigation, the collation of data from more recent studies would further consolidate the status of MRSA growth now; thus, increasing the validity of this investigation further.

Evaluation of the Claim

The research question, ‘Does the antibiotic, methicillin prove ineffective in treating Staphylococcus aureus infections in current times compared to its first introduction in 1960?’ has been addressed by collating evidence on the numerous aspects of the question. Evidence authenticates the current ineffectiveness of methicillin in the treatment of S. aureus infections compared to its successful use in 1960. Therefore, the findings of this investigation, if applied to the claim, suggest the claim is true. In this case, methicillin has ‘had its day’ in treating S. aureus infections due to the overuse of antibiotic. Due to the increasing rate of overuse of medication, more bacteria would likely have developed resistance to bacteria and hence, resulted in an ineffective treatment to illnesses.

Improvements and Extensions to the Investigation

To address the limitations of the evidence identified above, improvements to the investigation could be conducted. This claim could be supported through the comparison between MRSA and another antimicrobial-resistant infection and investigating the prevalence and growth of each overtime. It may be appropriate to investigate vancomycin-resistant Enterococcus (VRE), another very common antibiotic-resistant bacteria, similar to that of MRSA. Whilst figure 3 represents some preventative measures of MRSA, further investigation into the treatment progress of MRSA may provide further insights on alternative antibiotics to penicillins. Additionally, investigating the effectiveness of the antibiotic, methicillin on other diseases may draw clearer relationships towards its overall efficiency in today’s society.

In extending this investigation, it may be appropriate to further explore the define daily dosage present in Canada and the Netherlands and consider applying it to other countries. Additionally, the creation of man-made antibiotics may be relevant, where the antibiotic would have characteristics that the bacteria would not be able to adapt to. Furthermore, investigating the cost of this application into society would aid in the response to the research question from a more economic viewpoint.

Conclusion

It is evident that through research conducted, this investigation validates the growth of inefficiency of methicillin in treating S. aureus over time. Factors such as overuse and misuse of antibiotics and natural bacterial evolution pave the way for bacteria to develop antimicrobial resistance to medicinal drugs.

Evidence attained, displays that over time, antibiotics such as methicillin have decreased effectiveness in its function, however, new research presents preventative measures which should be considered in controlling antimicrobial resistance. Thus, the claim, ‘Antibiotics have had their day’, can be considered true as all elements of the claim have been asserted correctly with the example of MRSA.