Common prescription drugs may increase risk of antibiotic resistance, study warns

TEL AVIV, Israel — Common prescription drugs that are not antibiotics can increase the risk of patients developing antibiotic resistance, new research shows.  Such medications, including those used in cancer chemotherapy and to treat digestive and heart problems, may put patients at risk of certain types of infection from drug-resistant bacteria.

The new study finds this resistance was mainly from infection caused by bacteria in the Enterobacteriaceae family that includes salmonella. These antibiotic resistant infections are in turn linked to longer hospital stays and potentially greater risk of death, scientists say.

Bacteria are thought to develop antibiotic resistance largely due to repeated exposure through over-prescribing, making recent antibiotic use a key risk factor for drug resistance. But in up to half of patients harboring drug resistant bacteria when they are admitted to hospital, there is no identifiable risk factor, scientists said.

Commonly used non-antimicrobial drugs (NAMDs) help to treat diseases and manage symptoms of chronic conditions, but they can cause unwanted side effects. A few commonly used NAMDs have recently been found to have a significant impact on the bacterial composition of the gut microbiome. However the role of NAMD use as a risk factor for infection with antibiotic-resistant bacteria has not been systematically studied, researchers add.

This new study highlights the importance of commonly used NAMDs as a risk factor for antibiotic resistance. Analyses show that the use of seven common drug categories is linked with increased resistance to antimicrobial drugs-SSRIs which help people manage symptoms of depression as well as typical antipsychotics used to treat mental health conditions such as schizophrenia.

Blood thinning drugs for stroke prevention in patients with irregular heartbeats, proton pump inhibitors (PPIs) which reduce the production of stomach acid, beta-blockers which help treat heart problems and chemotherapy drugs called antimetabolites commonly used to treat cancers and inflammatory diseases have also been linked to increasing antibiotic resistance.

The researchers also found that three drug classes – PPIs, beta-blockers and antimetabolites – were significantly linked with resistance to third-generation cephalosporins, trimethoprim-sulfamethoxazole and fluoroquinolones.

Antimetabolites appeared to have the strongest impact on antibiotic resistance, the study shows.

“Our findings highlight the importance of non-antimicrobial drug exposure as a risk factor for antibiotic resistance,” says lead author Dr. Meital Elbaz of the Tel Aviv Medical Center in a statement. “We urgently need larger studies with more drug classes to confirm the discovery and to clarify the biological link between common prescription drugs and antibiotic resistance.”

Researchers examined data from 1,807 adults admitted to a tertiary-level academic hospital in Tel Aviv between January 1, 2017, and April 18, 2019, with a diagnosis of upper urinary tract infection, and a positive urine or blood culture growing Enterobacteriaceae. Use of 19 non-antimicrobial drug classes prior to hospital admission was retrieved from electronic medical records.

Antimicrobial drug-resistant organisms were found in over half of patient samples (944/1,807). And multidrug-resistant organisms – resistant to three or more classes of antibiotics – were identified in around a quarter of episodes (431/1,807).

The research was presented at this year’s European Congress of Clinical Microbiology & Infectious Diseases (ECCMID).

SWNS writer Chris Dyer contributed to this report.