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Foreign Invaders: Antibiotics in EMS

By: Austin Brook

When faced with life-threatening infections or acute bacterial illnesses, healthcare providers in the emergency care setting wield a powerful tool - antibiotics. These medications, designed to combat bacterial pathogens, are pivotal in saving lives and mitigating the severity of infections. From sepsis and pneumonia to urinary tract infections and skin abscesses, antibiotics are often the first line of defense, providing a crucial bridge until a definitive diagnosis can be established. However, only some prehospital programs nationwide leverage these essential medications because their use requires a nuanced and judicious approach. 

Striking the right balance between swift intervention and judicious stewardship is paramount, especially in an era marked by the looming threat of antibiotic resistance. In this blog post, we will delve into the intricate world of antibiotics in prehospital emergency care. We will explore their indispensable role, their challenges, and the strategies employed to ensure their effective and responsible utilization. When it is all said and done, I was hoping you could decide whether or not the future of EMS care includes frontline protocols aimed at the devastation of life's most dangerous pathogens. 

A brief history

The story of antibiotics is a testament to human ingenuity and the remarkable strides made in medical science. It began in the early 20th century when infectious diseases wielded devastating power over populations worldwide. The discovery of antibiotics marked a turning point in medicine, heralding a new era of therapeutic possibilities and fundamentally altering the course of healthcare.

In 1928, Sir Alexander Fleming, a Scottish bacteriologist, stumbled upon a curious phenomenon in his laboratory at St. Mary's Hospital in London. A petri dish containing Staphylococcus bacteria, inadvertently contaminated with mold, revealed a zone of inhibition - a clear ring devoid of bacterial growth surrounding the mold. This accidental encounter led to the identification of penicillin, the world's first antibiotic, and the birth of a medical revolution.

Since Fleming's groundbreaking discovery, a myriad of antibiotics have been developed, each with its unique properties and applications. From penicillin to cephalosporins, macrolides to fluoroquinolones, these drugs have become indispensable tools in the fight against bacterial infections. Nevertheless, with their proliferation, new challenges have emerged - chief among them the growing threat of antibiotic resistance and life-threatening allergies.

The role of antibiotics in prehospital care

Regarding life-threatening bacterial infections, the adage "time is tissue" remains true. Emergency departments across the world understand this foundational concept with the implementation of code sepsis protocols aimed at screening and intervening for patients at high risk for these infections. Well, if "time is tissue," wouldn't the prehospital environment be the best place to initiate these therapies? Of course! Unfortunately, nothing in medicine is so black and white. Astute clinicians must weigh the risks of resistance, microbial sensitivity and patient allergies. Having worked in the ED setting, I can attest that these skills can be extrapolated to a knowledgeable and experienced prehospital provider. 

While there may be limited antibiotics use in the prehospital setting, there are three cases where their use should be explored:

  1. Sepsis, a systemic response to severe infection that requires immediate and aggressive intervention from competent healthcare providers. Antibiotics serve as a potent weapon against the invading pathogens, halting their spread and preventing further organ dysfunction (Baghdadi et al., 2020).

  2. In cases of bacterial pneumonia, early antibiotic treatment is imperative. By targeting the specific bacteria responsible, antibiotics can slow the progression of the infection and improve patient outcomes (Khan et al., 2015).

  3. 3. For patients with necrotizing soft tissue infections, prompt administration of antibiotics is critical. These aggressive infections can rapidly escalate, and antibiotics are pivotal in saving life and limb until healthcare providers can provide definitive surgical intervention (Urbina et al., 2021).

In these scenarios, the judicious and timely use of antibiotics acts as a life-saving therapy for critically ill patients. 

Challenges and considerations

If you have ever taken a microbiology course, you likely learned about Gram staining. You may have even done it yourself! In short, Gram staining is a microbiological technique developed by Danish bacteriologist Hans Christian Gram in the late 19th century. It is used to differentiate and categorize bacterial cells into two groups: Gram-positive and Gram-negative. This process is a fundamental concept in microbiology and is often one of the first steps in identifying and classifying bacterial species. It provides valuable information about the cell wall structure of bacteria, which can be critical in selecting appropriate antibiotics for treatment. Well, that is simple enough! Suppose we add bacterial smearing, iodine staining and microscopic evaluation to the national registry scope of practice and advocate for high-powered microscopes on every ambulance. In that case, clinicians can safely identify and treat these infections in a jiff! 

Naturally, that is an impractical solution to the problem, which leads us to the discussion of empiric vs targeted therapy. In short, empiric antibiotic therapy can be initiated based on clinical judgment and knowledge of common pathogens without waiting for specific culture results. It provides broad-spectrum coverage. Targeted antibiotic therapy, on the other hand, is based on culture and sensitivity results, allowing for a more precise and tailored treatment approach with narrower-spectrum antibiotics. Antibiotic administration in the emergency department setting is based on an empiric approach to treatment. Conveniently, the most common pathogens to cause the illnesses above fall into our "gram-positive" basket of microbes. These bugs are staphylococcus, streptococcus, enterococci and C. difficile. These four bugs are susceptible to the oldest form of antibiotics available, Sir Alexander Fleming's miracle elixir, penicillin. 

Penicillin is a member of a large group of antibiotics called beta-lactam antibiotics. What sets these antibiotics apart is their distinctive chemical structure, characterized by a four-membered cyclic amide ring, known as the beta-lactam ring. Beta-lactam antibiotics interfere with the synthesis of bacterial cell walls, a vital process for bacterial survival and reproduction. Specifically, they inhibit the action of enzymes called transpeptidases or penicillin-binding proteins (PBPs) involved in the cross-linking of peptidoglycan strands, a key component of bacterial cell walls. By mimicking a portion of the peptidoglycan structure, the beta-lactam antibiotics effectively 'trick' these enzymes, leading to the disruption of cell wall formation. 

This disruption weakens the bacterial cell, rendering it susceptible to osmotic lysis, ultimately causing cell death. That should be the end of the discussion, right? Unfortunately, these crafty organisms looked at these beta-lactam antibiotics and said, "Some bacteriologist will not outsmart me." Over time, these bacteria crafted a defense to this class of antibiotics. Many now wield a powerful enzyme designed to destroy the beta-lactam ring, rendering these antibiotics completely useless. As you may have guessed, this enzyme is called beta-lactamase. Now, surely that is the end of the discussion? Well, not exactly. After an embarrassing defeat, bacteriologists returned to the drawing board and decided, "Some single-celled organism will not outsmart me." They created a way to fortify this beta-lactam ring, making it impenetrable to beta-lactamase. Having exhausted their creativity on the consecration of these new antibiotics, they named this new compound... the beta-lactamase inhibitor. 

So, which penicillin antibiotics contain this fancy defense? You might recognize them. The typical combinations include amoxicillin with clavulanic acid (Augmentin) and piperacillin with tazobactam (Zosyn). These antibiotics represent the "big guns," with Zosyn being an intravenous formulary commonly given in the emergency department setting. There is one more common group of antibiotics that share a similar structure to penicillins. Cephalosporins share a typical beta-lactam ring structure with penicillin antibiotics (pictured below in yellow), but they possess a distinct six-membered dihydrothiazine ring in addition to the beta-lactam ring. 

This structural modification contributes to their unique spectrum of activity. Some common first-generation cephalosporins are cephalexin (Keflex) and cefazolin (Ancef), with third and fourth-generation cephalosporins boasting that beta-lactamase inhibitor. These are ceftriaxone (Rocephin) and cefepime (Maxipime). It is important to note that patients with true IgE-mediated allergies to penicillin (anaphylaxis) should never receive cephalosporins due to their similar chemical structure.

Administration and monitoring

So, what is the best course of action when treating our three prehospital infections? 

  1. Identify an antibiotic with wide use against gram-positive bacteria.

  2. Consider resistance in the form of beta-lactamase-producing bacteria.

  3. Consider patient allergies 

Cephalosporins are versatile antibiotics used in emergency care due to their effectiveness against a broad spectrum of pathogens. When targeting Gram-positive bacteria, such as Staphylococcus and Streptococcus species, a third-generation cephalosporin like ceftriaxone, is an excellent choice as it addresses all three of our key points above! Rocephin is available as a reconstituted IV and is commonly dosed at 40mg/kg to a max of 2g. 


  • Early administration of antibiotics in emergency care is paramount in effectively treating bacterial infections and can significantly impact patient outcomes. 

  • The concept of "time is tissue" underscores the urgency in initiating appropriate antibiotic therapy. In many cases, the severity of an infection and its potential complications are directly correlated with the time it takes to begin antibiotic treatment. 

  • Delayed administration can allow bacteria to proliferate and spread, leading to more severe infections, increased tissue damage, and even systemic complications like sepsis, where every hour of delay in administering appropriate antibiotics is associated with a measurable increase in mortality risk. 

  • This proactive approach in prehospital care not only helps to save lives but also reduces the overall burden of illness on patients and the healthcare system as a whole.


Baghdadi, J. D., Brook, R. H., Uslan, D. Z., Needleman, J., Bell, D. S., Cunningham, W. E., & Wong, M. D. (2020). Association of a care bundle for early sepsis management with mortality among patients with hospital-onset or community-onset sepsis. JAMA Internal Medicine, 180(5), 707. 

Khan, R. A., Bakry, M. M., & Islahudin, F. (2015). Appropriate Antibiotic Administration in Critically Ill Patients with Pneumonia. Indian journal of pharmaceutical sciences, 77(3), 299–305.

Urbina, T., Razazi, K., Ourghanlian, C., Woerther, P. L., Chosidow, O., Lepeule, R., & de Prost, N. (2021). Antibiotics in Necrotizing Soft Tissue Infections. Antibiotics (Basel, Switzerland), 10(9), 1104.

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