Via The New York Times: ‘We’re Out of Options’: Doctors Battle Drug-Resistant Typhoid Outbreak. Excerpt:
The first known epidemic of extensively drug-resistant typhoid is spreading through Pakistan, infecting at least 850 people in 14 districts since 2016, according to the National Institute of Health Islamabad.
The typhoid strain, resistant to five types of antibiotics, is expected to disseminate globally, replacing weaker strains where they are endemic. Experts have identified only one remaining oral antibiotic — azithromycin — to combat it; one more genetic mutation could make typhoid untreatable in some areas.
Researchers consider the epidemic an international clarion call for comprehensive prevention efforts. If vaccination campaigns and modern sanitation systems don’t outpace the pathogen, they anticipate a return to the pre-antibiotic era when mortality rates soared.
“This isn’t just about typhoid,” said Dr. Rumina Hasan, a pathology professor at the Aga Khan University in Pakistan. “Antibiotic resistance is a threat to all of modern medicine — and the scary part is, we’re out of options.”
Typhoid fever, caused by the Salmonella typhi bacteria, is a highly infectious disease transmitted by contaminated food or water. It causes high fevers, headaches and vomiting. About 21 million people suffer from typhoid each year, and about 161,000 die, according to the World Health Organization.
Typhoid is endemic to Pakistan, where poor infrastructure, low vaccination rates and overpopulated city dwellings persist. Doctors in the Sindh province were not surprised by an outbreak in November 2016 — until cases proved unresponsive to ceftriaxone, used to treat multidrug-resistant, or MDR, strains of typhoid.
Only four isolated cases of extensively drug-resistant, or XDR, typhoid had previously been reported worldwide, according to Dr. Elizabeth Klemm, an infectious disease geneticist at the Wellcome Sanger Institute in England.
The outbreak’s origins were clear: Early case mapping revealed large clusters of victims around sewage lines in the city of Hyderabad. Dr. Hasan’s colleagues visited the region and found water sources that could be contaminated by leaking sewage pipes.
Four deaths have been reported so far, according to the National Institute of Health Islamabad. At least one travel-related case has been detected in the United Kingdom.
Genetic sequencing revealed that a common, aggressive MDR typhoid strain called H58 interacted with another bacteria, likely E. coli, and acquired from it an additional DNA molecule, called a plasmid, that coded for resistance to ceftriaxone.
The findings were disturbingly simple: XDR strains can materialize in one single step, virtually anywhere where the H58 strain and the added plasmid are both present — whether a sewer system or even a single human gut.
“There are multiple worst-case scenarios,” said Dr. Klemm. “One is that this strain spreads to other regions through migration. But the other is that it pops up elsewhere on its own — plasmids with drug resistance are everywhere.”
