Superbug in infections showed mutation
The superbug that infected nearly a dozen Americans who recently underwent weight-loss surgery at a Tijuana hospital had a particularly nasty genetic mutation that set off alarm bells after patients began showing up in hospitals and doctors officers with painful wounds.
The U.S. Centers for Disease Control and Prevention issued a travel warning this week, notifying the public that 11 Americans who traveled to Tijuana hospitals for weight-loss surgery had become infected with drug-resistant pseudomonus aeruginosa infections during their stays.
Dr. David “Cal” Ham, a CDC medical officer, said Friday that the particular strain of pseudomonus bacteria involved in 11 confirmed cases had metallo-beta lactamase genes. Often called “VIM” by the epidemiological community, Ham explained that these genes cause the microbes that carry them to excrete enzymes that destroy carbapenems, a workhorse class of antibiotics with some of the broadest efficacy in medicine.
The pseudomonus strains that caused the Tijuana outbreak were already drug resistant, Ham said. Picking up carbapenem-fighting chops made an already serious threat more deadly.
“VIM makes this more concerning than your run-of-the-mill, drugresistant pseudomonus,” Ham said.
One patient with an outbreak-linked infection has died, the physician said, though it’s impossible to say that it was just pseudomonus that caused that outcome.
“The patient who died did have a number of other underlying medical conditions, so we can’t say for sure if this infection was the primary cause of death,” Ham said.
Though six of the cases underwent bariatric surgeries at Grand View Hospital just south of the U.S. Mexico border, Ham said that so far not a single sickened patient was a California resident. Infected medical tourists came from seven states: Arkansas, Arizona, Oregon, Utah, Texas, Washington and West Virginia.
Some of the patients, Ham said, have received treatment with other antibiotics and have seen their infections subside while others are still in hospitals suffering as doctors work down a dwindling list of available options.
“There are still active infections, unfortunately,” Ham said. “Several of the isolates involved are susceptible only to a couple of, I would say, less-thanoptimal antibiotics that have significant side effect profiles.”
Patients involved in the outbreak underwent surgeries from August through November with one case subsequently identified in 2015. Two additional suspected cases, Ham said, remain under investigation.
The CDC is urging doctors across the United States to report any cases of pseudomonus so that specialized testing can determine whether VIM or a handful of other problematic mutations that confer carbapenem resistance are present.