Wonderful World of Antibiotics

While the existence of bacteria has been known since 1676, when they were first observed under a Dutch microscope, but it wasn’t until the early 20th century that scientists really understood what was going on in this microscopic world. So what are these wonder drugs?

What’s their history?

Antibiotics have technically been around for as long as bacteria have, which is a while, give or take 3 billion years. While Ancient Egyptians, Chinese and Romans were known to use mouldy bread to treat wounds, here is a VERY brief history covering some of the more ‘exciting’ bits:

  • 1870 – Sir John Scott Burdon-Sanderson noted mould could inhibit bacterial growth (Gould, 2016)
  • 1882 – Paul Ehrlich discovered that certain bacterial cells could be dyed, while others weren’t (Schwartz, 2004)
  • 1909 – Ehrlich and his team used an arsenic based chemical to successfully treat syphilis (Gould, 2016)
  • 1928 -Alexander Fleming discovered penicillin (Fleming, 1929)
    1940 – Howard Florey and Ernst Chain created purification technique for penicillin (Chain et al., 1940)
  • 1952 – Christian Missionaries sent a soil sample from Borneo which contained Streptomyces orientalis, from which vancomycin was extracted (Geraci et al., 1956)
  • 1959 – antibiotic resistance identified. Methicillin developed to combat this (Knox, 1960; Harkins et al., 2017)
  • 1960’s – cephalosporins developed (Wick, 1967; Zaffiri, Gardner and Toledo-Pereyra, 2012)
  • 1978 – teicoplanin developed from Actinoplanes teichomyceticus (Parenti et al., 1978)
  • 1980’s – ciprofloxacin introduced (Andersson and MacGowan, 2003)
  • 1995 – meropenem licenced (Papp-Wallace et al., 2011)
  • 2010’s – newer antibiotics such as dalbavancin, oritavancin, ceftobiprole and ceftaroline become available (Gould, 2016)

Antibiotic Actions

Cell wall – inhibition of cell wall synthesis by preventing cross linking of certain peptidoglycans.

Growth factor analogue – growth factors are essential extras needed by certain bacteria to function, analogues of these are synthetic versions that disrupt the cells metabolism as the bacterium takes up the non-functioning analogue instead of the real one. An example of this is isoniazid, an antibiotic we came across in the TB post.

Protein synthesis – some antibiotics prevent bacterial proliferation by mucking up its ability to make new proteins. These target ribosome subunits 30S or 50S, preventing them from translating any bacterial RNA.

Nucleic acid synthesis – certain drugs can interfere with the enzymes responsible for packaging bacterial DNA (quinolones), preventing the elongation of RNA chains by binding with polymerases (rifampin) or binding to the base pairs themselves (actinomycin).

Folic acid metabolism – unlike in humans and other animals, bacteria make their own folic acid and use it as an essential part of bacterial DNA synthesis, by using synthetic analogues of folic acid components, this process can be broken down.

Antibiotics

Taken from Madigan et al. (2017)

This is just a few of the mechanisms used by the more commonly used antibiotics, all of which either kill or prevent the bacteria from growing (Madigan et al., 2017).

Antibiotic resistance

This topic really deserves a whole post on its own, but definitely needs an honourable mention in this one. Antibiotic resistance occurs when the bacteria being targeting by the antibiotic develops its own mechanisms for either making the drug ineffective or removing/killing it before it can do any of the jobs listed above. Bacteria are also extra sneaky because they can then pass on this resistance to all its neighbours through a process called horizontal gene transmission, on top of giving these new genes to its own daughter cells (video about this here)

Things to think about

Allergies – this goes without saying and checking a patient’s allergies is one of the first things any nurse should do before administering any medication, not just antibiotics. Making sure these are clearly documented and communicated to other relevant team members is also vital.

Know the basics – there is no expectation for nurses to know pharmacy level stuff about any drug, but there is a legal requirement to have a good general understanding of what the drug is for and its side-effects (Royal Pharmaceutical Society, 2019).

Also know any “quirks” – take gentamicin, one of a bunch of more hardcore antibiotics commonly given IV. However, this one must be given slowly as there is a risk of ototoxicity, where the drug causes irreversible damage to the inner ear, leading to problems with balance. This risk is still there when given slowly, but greatly reduced  (Ahmed et al., 2012; BNF, 2019).

Not just the bad guys – it’s important to bare in mine that antibiotics don’t just kill of the bacteria you want them too, but also have the potential to kill off any others living in or on the body. Patients can get all sorts of nasty and annoying side-effects as the antibiotics are viciously killing off all of their normal microbiota, giving them things like thrush or diarrhoea.

Completing the treatment – ensuring patients are encouraged to complete their full courses of treatment can help reduce the ever increasing prevalence of antibiotic resistance.

Drug interactions – all drugs have the capacity to interact with another drug, but antibiotics are particularly famous for their relationship not only with birth control, but also alcohol. Ensuring patients are aware that they either need to take extra care with contraception during their treatment, or that mixing certain antibiotics with alcohol is a bad idea can help reduce any untoward events.

So what?

Antibiotics are a both a wonder drug and a hindrance to patients; they can bring people back from the brink of death, but also give them any number of horrid side-effects. While its vital that nurses have a good understanding of the antibiotic basics, they also need to get to grips with the implications of taking these drugs and the effect this has on patients, both physically and emotionally. Nurses need to appreciate the reasons patients don’t always want to take their antibiotics and ensure that these individuals have all the necessary information so that they can make an informed decision. Increasing patient awareness of antibiotic resistance and the importance of completing the therapy in full can also help patients for the future along with discouraging antibiotic use for non-bacterial infections.

References

Ahmed, R. M. et al. (2012) ‘Gentamicin ototoxicity: a 23-year selected case series of 103 patients’, The Medical Journal of Australia, 196(11), pp. 701–704. doi: 10.5694/mja11.10850.

Andersson, M. I. and MacGowan, A. P. (2003) ‘Development of the quinolones’, Journal of Antimicrobial Chemotherapy, 51(90001), pp. 1–11. doi: 10.1093/jac/dkg212.

BNF (2019) Gentamicin. NICE. Available at: https://bnf.nice.org.uk/drug/gentamicin.html#sideEffects (Accessed: 3 March 2019).

Chain, E. et al. (1940) ‘Penicillin as a Chemotherapeutic Agent’, The Lancet, 236(6104), pp. 226–228. doi: 10.5555/URI:PII:S0140673601087281.

Fleming, A. (1929) ‘On the Antibacterial Action of Cultures of a Penicillium, with Special Reference to their Use in the Isolation of B. influenzæ’, British journal of experimental pathology, 10(3), p. 226. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2048009/ (Accessed: 25 February 2019).

Geraci, J. et al. (1956) ‘Some laboratory and clinical experiences with a new antibiotic, vancomycin.’, Mayo Clin Proc, 31(21), pp. 564–82. Available at: http://www.ncbi.nlm.nih.gov/pubmed/13425363 (Accessed: 2 March 2019).

Gould, K. (2016) ‘Antibiotics: from prehistory to the present day’, Journal of Antimicrobial Chemotherapy, 71(3), pp. 572–575. doi: 10.1093/jac/dkv484.

Haas, L. F. (1992) ‘Antoni van Leeuwenhoek 1632-1723.’, Journal of neurology, neurosurgery, and psychiatry, 55(4), p. 251. Available at: http://www.ncbi.nlm.nih.gov/pubmed/1583507 (Accessed: 25 February 2019).

Harkins, C. P. et al. (2017) ‘Methicillin-resistant Staphylococcus aureus emerged long before the introduction of methicillin into clinical practice’, Genome Biology, 18(1), p. 130. doi: 10.1186/s13059-017-1252-9.

Knox, R. (1960) ‘A new penicillin (BRL 1241) active against penicillin-resistant staphylococci.’, British medical journal, 2(5200), pp. 690–3. Available at: http://www.ncbi.nlm.nih.gov/pubmed/14410240 (Accessed: 2 March 2019).

Madigan, M. T. et al. (2017) Biology of Microorganisms. 15th edn. Harlow: Pearson.

Papp-Wallace, K. M. et al. (2011) ‘Carbapenems: past, present, and future.’, Antimicrobial agents and chemotherapy, 55(11), pp. 4943–60. doi: 10.1128/AAC.00296-11.

Parenti, F. et al. (1978) ‘Teichomycins, new antibiotics from Actinoplanes teichomyceticus Nov. Sp. I. Description of the producer strain, fermentation studies and biological properties.’, The Journal of antibiotics, 31(4), pp. 276–83. Available at: http://www.ncbi.nlm.nih.gov/pubmed/659325 (Accessed: 25 February 2019).

Royal Pharmaceutical Society (2019) Professional Guidance on the Administration of Medicines in Healthcare Settings. Available at: https://www.rpharms.com/Portals/0/RPS document library/Open access/Professional standards/SSHM and Admin/Admin of Meds prof guidance.pdf?ver=2019-01-23-145026-567 (Accessed: 3 March 2019).

Schwartz, R. S. (2004) ‘Paul Ehrlich’s Magic Bullets’, New England Journal of Medicine, 350(11), pp. 1079–1080. doi: 10.1056/NEJMp048021.

Wick, W. E. (1967) ‘Cephalexin, a new orally absorbed cephalosporin antibiotic.’, Applied microbiology, 15(4), pp. 765–9. Available at: http://www.ncbi.nlm.nih.gov/pubmed/4383049 (Accessed: 2 March 2019).

Zaffiri, L., Gardner, J. and Toledo-Pereyra, L. H. (2012) ‘History of Antibiotics. From Salvarsan to Cephalosporins’, Journal of Investigative Surgery, 25(2), pp. 67–77. doi: 10.3109/08941939.2012.664099.

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