By Dr.Abdul Razzak Shaikh,
A silent killer disease is on the rise in Sindh, including Hyderabad and Karachi. The spread of the disease, ‘superbug’ typhoid fever, has rung alarm bells.
The superbug typhoid fever is characterized by a Salmonella Typhi that does not respond to most antibiotics.
The disease is caused by the excessive consumption of antibiotics.
Drinking contaminated water is the prime cause of this disease and cases are being reported in a lot of numbers in Sindh.
Medical practitioners advise precaution in this connection. Doctors should give a second thought before finalizing a prescription as antibiotics are triggering the disease, experts said. The superbug typhoid may turn out to be fatal.
An outbreak of typhoid fever in Pakistan is being caused by an extensively drug-resistant “superbug” strain, a sign that treatment options for the bacterial disease are running out. Researchers from Britain’s Welcome Sanger Institute who analyzed the genetics of the typhoid strain found it had mutated and acquired an extra piece of DNA to become resistant to multiple antibiotics.
An outbreak of drug-resistant typhoid that began in Hyderabad in Pakistan in November 2016 is still spreading, according to experts from Aga Khan University who worked with the Sanger team.
The researcher found the bacterial strain causing the outbreak is now resistant to five antibiotics in total, more than seen in an outbreak before.
Typhoid is a highly contagious infection caused by the Salmonella enteric serovar Typhi bacteria. It is contracted by consuming contaminated foods or drinks and symptoms include nausea, fever, abdominal pain and pink spots on the chest. Untreated, it can be fatal.
The team found it was being caused by a strain known as H58, which is already known to be linked to drug-resistant cases. Looking further, they found this H58 strain had gained an extra strand of bacterial DNA, a plasmid – that encoded for additional antibiotic resistance genes. The study’s results were published in the scientific journal mBio.
Charlie Weller, head of vaccines at Britain’s Welcome Trust global health charity, said the findings were a clear warning that “treatment options for typhoid are running out” and focusing on prevention now vital.
A new vaccine against typhoid was approved by the World Health Organization and the GAVI global vaccine alliance said it had earmarked $85 million to help support the introduction of typhoid vaccines in poor countries.
After antibiotics were first introduced to treat typhoid in the 1940s, typhoid’s mortality rate plummeted from around 26 percent to just 1 percent.
But within 20 years, the first cases of typhoid resistant to chloramphenicol, one of the three first-line treatments for typhoid appeared, signaling a battle between antibiotics and bacteria.
Typhoid strains resistant to all three first-line treatments, known as multidrug-resistant (MDR) typhoid strains, were quick to follow those resistant to only one antibiotic. And when doctors began using second-line antibiotics, more modern but expensive drugs such as fluoroquinolones, typhoid followed with resistance against those drugs too.
A particularly aggressive strain of MDR typhoid, H58, first emerged in the 1990s. H58 has grabbed our attention because, while other MDR typhoid strains have mostly remained in the local area where they first appeared, H58 has quickly spread across the globe. It’s a fast learner that is able to not only evolve quickly but also multiply and spread rapidly.
Recently, the world saw yet another evolution of the H58 strain. In November 2016, doctors in Sindh, Pakistan, observed cases of a novel H58, S.Typhi strain that was resistant to not only the three first-line antibiotics and fluoroquinolones but also a third-generation cephalosporin called ceftriaxone. This new strain is classified as extensively drug-resistant (XDR) typhoid. It is only susceptible to a limited number of antibiotics, which can be expensive and difficult to access, especially for low- and middle-income countries.
In an effort to learn more about this new XDR typhoid, at Aga Khan University in Pakistan to sequence its DNA, research that was published in mBio. They found three concerning issues. First, found that S.Typhi transformed from MDR to XDR in a single step by acquiring just one highly mobile DNA molecule (what we call a “promiscuous” plasmid) from another bacteria such as E. coli. MDR H58 typhoid in any location, therefore, has the potential to become XDR typhoid in a similar manner.
Second, they found that the new XDR strain is an end product of a global chain of antibiotic-resistant bacteria. The plasmid that created XDR typhoid is present in a variety of diverse geographic settings across the globe, and once created, XDR typhoid rapidly reproduces itself. This is a troubling development because previous reports of XDR typhoid have been sporadic and isolated, while this particular strain has already caused a large-scale outbreak and is spreading within and outside Pakistan. It has already been carried as far as the United Kingdom.
Finally, findings confirm the fact that the antibiotic arsenal for typhoid treatment is fading. We can no longer rely solely on antibiotics to treat typhoid fever. We need to shift our paradigm away from treatment and toward prevention.
Fortunately, we now have a promising new preventative tool. Typhoid conjugate vaccines are a newly WHO-prequalified class of typhoid vaccines that, compared to older typhoid vaccines, are longer-lasting, require fewer doses, and can be given to children as young as 6 months of age. Because they can be given to young children, countries can include typhoid conjugate vaccines in routine immunization programs, developing widespread immunity to typhoid and stopping dangerous strains like H58 from spreading and evolving.
On 6th February 2019, Director General Health Sindh issued the letter to all health facility centers that they must use the AZITHROMYCIN and CARBAPENEMASE are a sensitive antibiotic for the treatment of XDR- typhoid fever and make ensure the availability of this medicine.
I think the only intervention that will work is improving access to clean drinking water, hygiene, sanitation and accelerating vaccination campaigns.