A drug-resistant superbug outbreak in Tijuana prompted the U.S. Centers for Disease Control and Prevention to issue a second travel warning this week, after nearly a dozen U.S. patients who traveled to the region for selective surgeries between August and December returned with potentially deadly infections.
“Over half of those infected with these bacteria had surgery at Grand View Hospital, Tijuana,” the CDC stated. “The others became infected after surgery at other hospitals and clinics.”
The bacteria, Pseudomonas aeruginosa, can spread through poorly cleaned equipment, and from health-care workers to patients, CDC warned.
“It’s actually a ubiquitous microbe, meaning it’s everywhere in the environment — it’s in water supplies, it’s in the soil and we come in contact with it on a frequent basis," said Victor Nizet, M.D., a professor at UC San Diego’s School of Medicine. "Now for a person with a healthy immune system, Pseudomonas is very unlikely to cause an infection. So most of us are not at risk."
"Once it’s in the hospital, because Pseudomonas is so good at living in the environment, it can persist,” Nizet added.
The bacteria is one of a growing number of infections that has become hard to treat by first-line antibiotics.
“Classical antibiotics, which are chemicals that were discovered in a test tube to kill bacteria or to block their growth, have been one of the most important classes of medicine in all of modern medicine,” Nizet said. “Probably cured more patients than all the other drug classes combined, but in the last few years we’ve seen increasing resistance.”
Nizet said a rise in superbug outbreaks is fueled by an overuse of antibiotics, which are not just used in medicines, but also in food production.
“When we expose bacteria to antibiotics, there’s a life or death challenge,” Nizet said. “And if there’s any way they can genetically mutate to survive that antibiotic, than it’s those resistant strains that will spread.”
“One of the unfortunate consequences of over aggressive antibiotic prescription is that all your good citizen bacteria that make up your normal microbiota that are very important for our health... are being killed by the friendly fire of too many antibiotics,” Nizet added. “That puts us in a vicious cycle to have increased risk of infection.”
Superbugs often strike hospitalized patients and people with weakened immune systems or chronic medical conditions. Some of potentially deadly bacteria includes methicillin-resistant Staphylococcus aureus (MRSA), Clostridium difficile (C. diff), and carbapenem-resistant Enterobacteriaceae (CRE). The U.S. Centers for Disease Control and Prevention estimates that at least 2 million Americans become infected with antibiotic-resistant bacteria and at least 23,000 people die each year as a direct result of these infections.
The World Health Organization recently reported superbugs could lead to 10 million deaths worldwide per year by 2050.
“Really, any human is susceptible to being colonized on and off with antibiotic resistant strains because they circulate among the humans,” Nizet said. “So once antibiotic use is very common among the population, then antibiotic-resistant strains will circulate.”
The alarming projection is why Nizet is leading a collaborative effort among San Diego research institutions to find a treatment.
The new research program, Collaborative to Halt Antibiotic Resistant Microbes, or CHARM, launched in January and is headquartered in the UC San Diego School of Medicine. The project is funded by a $9.5 million grant from the National Institute of Allergy and Infectious Diseases at the National Institutes of Health (NIH).
"To come up with novel solutions," Nizet said. "They include nano therapies, immune boosting therapies, new vaccines against the pathogens. And (to) elevate San Diego as a leader nationally and internationally in addressing this crisis."
