Antimicrobial Resistance

Infectious microorganisms like bacteria, viruses, and fungi can cause diseases in human beings, plants, and animals. To fight these infections, many classes of therapeutic drugs have been developed, such as antibiotics (against bacteria), antifungal, and antiviral drugs. However, since microorganisms are constantly evolving, they can change and develop ways to circumvent and defeat the effect of these drugs and medications. This is termed antimicrobial resistance. This happens, especially, when there is heavy use of antimicrobial drugs, forcing the organism to evolve a defense mechanism. Without effective medication against these resistant organisms, it will be difficult to stop them from multiplying in a patient which can lead to the infection becoming worse.

Antimicrobial resistance has been declared “one of the top 10 global public health threats facing humanity” by the World Health Organization. In particular, multidrug resistance bacteria, that is, bacteria resistant to multiple medications or commonly called superbugs, cause 4.95 million people to die each year. To address this major health issue, antimicrobial stewardship programs have been developed, which are guidelines on how to optimize the use of medication to prevent these microorganisms from developing resistance.

The main goals of the antimicrobial stewardship programs are to choose the antibiotics appropriately, lower the duration of antibiotic usage, decrease hospital stay and treatment costs, and reduce the chances of new resistant microorganisms from developing. The programs have shown to be effective to a certain extent while dealing with pneumonia, bloodstream infections, and urinary tract infections. The effectiveness of these programs on post-surgery outcomes has not been well studied.

Why Is Antimicrobial Stewardship Important for Abdominal Surgery?

After any surgery, there is a chance of acquiring different kinds of infections. Specifically, with abdominal surgery, the chance of getting an infection after surgery is reported to be between 8 and 20%. This demands developing and testing the effectiveness of an antimicrobial stewardship program in these settings.

The two most common types of infections after abdominal surgery are intra-abdominal infection and surgical site infection:

• Intra-abdominal infection after surgery, which is termed post-operative peritonitis, is the infection of cells in the abdominal lining by bacteria that can, for example, leak through a perforation in the gut and affect the abdominal area.
• Surgical site infection refers to infection of the wound at the site of the surgery.

Since infection possibility is high in post-operative abdominal surgery, to help with antimicrobial stewardship, a first step to consider is infection control measures before an operation.

Which Preventive Infection Control Measures Can Be Taken before the Operation?

Patients undergoing surgery need to be examined for their risk of developing infections. A patient can be at high risk for developing infections due to patient-related conditions like diabetes, immunosuppression, or chronic kidney disease, or surgery-related conditions such as existing infected wounds, use of invasive devices, etc.

Based on the risk factor, appropriate pre-surgery antibiotics treatment, termed perioperative antibiotic prophylaxis, needs to be administered. With the right treatment, the rate of post-operative wounds can be reduced by up to 80%.

Some of the guidelines of the pre-surgery treatment procedure for administering antibiotics appropriately are:

• a yearly review of the antibiotic treatment based on local pathogen data must be done,
• antibiotics must be administered 30–60 mins prior to the incision procedure,
• a single dose of antibiotics is preferred, and
• antibiotics must not be administered over multiple days.

Patients should also be screened for multidrug-resistant bacteria, especially under certain conditions where the patient might have come in contact with another patient with these bacteria or been in contact with a person from a country with a high prevalence of them, or have themselves been an in-patient in the hospital in the previous 12 months.

Antimicrobial Stewardship in Post-Operative Intra-Abdominal Infections

Intra-abdominal infections can occur due to many reasons related to abdominal health. However, when it occurs due to a post-operative issue, it is especially harmful because there is an increased rate of multidrug-resistant bacteria and is associated with a higher mortality rate. There are various types of bacteria that affect the different parts of the digestive tract. Fungal infections are also possible. Early detection of the infecting organisms, especially if they are multidrug-resistant bacteria is critical. The detection will particularly help with improving the choice of antibiotic administered and in preventing spreading of the multidrug-resistant bacteria in the hospital.

Treating this intra-abdominal infection requires an interdisciplinary approach involving surgeons, intensive care specialists, and an antimicrobial stewardship team. One of the main treatment procedures involves conducting surgery to remove the source of the infection. This has been shown to reduce mortality significantly. After this surgery, antibiotic therapy must still be given but the duration can be reduced, which is helpful to avoid bacteria developing resistance to antibiotics.

Along with surgery to avoid progression to sepsis (where the infection spreads and affects the whole body), a broad antibiotic treatment needs to be started immediately when infection is diagnosed. The current antimicrobial stewardship guidelines must be followed, and the patient’s risk factors and local multidrug-resistant bacteria information have to be taken into account when administering antibiotic treatment. When more detailed information about the microbial infection is available, it is important to use narrow-spectrum antibiotics to treat the specific infection. This can help avoid the further development of resistant bacteria.

Antimicrobial Stewardship in Surgical Site Infection

Surgery site infection or wound infection has been shown to occur with a high rate of 10.1 cases in 100 operations for colorectal surgery, which is one of the abdominal surgeries. Deep infection where body cavities and organs also get infected occur in 61% of the cases. While there are many advances in treating these infections, morbidity can occur due to surgical site infection. Most wound infections are caused by mixed bacteria and not as many viruses or fungi.

A main preventive treatment currently recommended is an antiseptic treatment after surgery which, for example, involves flushing the wound with 0.04% polyhexanide solution instead of 0.9% saline.

Treatment of surgical site infections involves surgery and treating the source of infection, for example, by removing the infectious tissue. With uncomplicated infections, surgery with antiseptic treatment may be enough, without the need for antibiotics to clear the infection. With infections that are more severe and with certain bacteria, however, an immediate antibiotic treatment needs to be administered similarly to that discussed for intra-abdominal infections.

In Conclusion

It has been realized that with regular monitoring and discussion by the antimicrobial stewardship teams with surgeons and doctors in the intensive care units and surgical wards, it is possible to reduce the use of broad-spectrum antibiotics, increase the use of narrow-spectrum antibiotics, decrease the duration of antibiotic therapy and lower the cost of treatment. All these eventually help in reducing the number of antimicrobial-resistant organisms which is the aim of antimicrobial stewardship programs.