Are Deadly Bacterial Infections Linked to Heavy Drinking?

Just in time for St. Patrick’s Day, a recent case study may link heavy drinking and associated medical treatments for this behavior with bacterial blood infections. Commonly referred to as bacteremia, these infections can cause symptoms ranging from mild fever and chills to gastrointestinal distress, mental confusion, or even death.

Research published this month in the Journal of Clinical Microbiology, demonstrates the need for promptly identifying bacteria involved in bacteremia infections, particularly in those with alcohol use disorder. A team of researchers headed by David J. Epstein, MD, from the Stanford Healthcare Medicine Department’s Division of Infectious Diseases & Geographic Medicine, presented the case of a 39-year-old homeless man who was a documented heavy drinker, but did not use drugs, who acquired an antibiotic-resistant strain of bacterial infection, called Anaerobiospirillum succiniciproducens, which can be fatal. Heavy drinkers receiving injections for their alcohol use disorder may be more susceptible to acquiring this type of infection.

“The patient in this case had an alcohol use disorder, a frequently-cited risk factor for A. succiniciproducens,” Dr. Epstein and colleagues explained in the report. The bacterium, while relatively rare, tends to affect patients with existing diseases or conditions and is often resistant to the antibiotics metronidazole and clindamycin, which are commonly used to treat abscesses, vaginal infections, and intestinal issues. In this case, the patient was admitted to the hospital with fever and a cough. The patient was also assaulted the previous day and was experiencing pain in his buttocks and thigh. The admitting physicians noted that the patient had a medical history of “alcohol use disorder treated with naltrexone,” which was “injected into the gluteal region monthly.” (Naltrexone was approved by the FDA in 1994 to treat alcoholism, because it tends to reduce cravings for alcohol by blocking its effects on the brain.) The patient himself reported that he drank “up to two dozen beer cans daily and smoked cigarettes.”

After blood cultures were collected, the patient received treatment for pneumonia with ceftriaxone and azithromycin, but fever continued, “and hypotension and altered mentation developed.” The physicians changed the treatment to vancomycin and cefepime on the second day. They opted to treat the persistent fever with metronidazole on day six, and on the following day, a CT scan revealed several infected areas in the gluteal region that may have been related to the naltrexone injections, the assault, or both. On day 11, blood cultures revealed the presence of A. succiniciproducens in the blood. Once the A. succiniciproducens was identified, the patient received intravenous ampicillin-sulbactam for six days, followed by two weeks of oral amoxicillin-clavulanic acid; the patient improved from that point on, with “repeat pelvis CT show[ing] resolution of abscesses.”

“Early diagnosis and appropriate antimicrobial therapy are crucial to the outcomes of bacteremic patients,” the authors observed, noting that “infrequently encountered anaerobic organisms,” such as A. succiniciproducens, may be difficult to identify because they are not necessarily included on biochemical panels and do not always show up reliably even when they are. These organisms also “may require long incubation times” that may slow the administration of the correct treatment. The authors added that most cases of this specific infection “consist of individuals mostly over 40 years of age with chronic medical conditions, including malignancy, diabetes mellitus, liver disease, alcoholism, and cardiovascular disease.”

In this case, the researchers speculated that the bacteremia could have originally infected the patient when he received a naltrexone injection, but since he had received so many antibiotics prior to the bacterium’s identification, its presence in those infected areas could not be confirmed.

Although patients have a responsibility to report chronic, heavy alcohol use to their medical practitioners, heavy alcohol use alone is not necessarily a red flag for this type of infection, and so patients and doctors have a responsibility to be aware of this potential problem when a patient presents with alcoholism. “[C]linicians should consider pyogenic complications of A. succiniciproducens bacteremia when patients with bacteremia have localizing signs or symptoms,” Dr. Epstein and his team concluded. “[A]s more bacterial species are added to… databases, the utility of this method of identification… will likely expand.”