Extensively Drug Resistant Salmonella Outbreak in Pakistan

4 Dec 2019

Extensive drug resistant typhoid outbreak in Pakistan

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Pakistan is experiencing a continuous surge of extensively drug-resistant (XDR) typhoid fever that began in city of Hyderabad in November 2016. This outbreak is not limited to the Hyderabad but cases are being reported from all over the country.

The XDR S. Typhi strain acquired a plasmid which confers resistance to multiple antibiotics including first-line antibiotics (i.e. chloramphenicol, ampicillin, and trimethoprim-sulfamethoxazole), fluoroquinolones and third-generation cephalosporins, luckily it is still susceptible to Azithromycin and Carbapenems

Clinical Manifestations: Salmonellosis ranges clinically from the common Salmonella gastroenteritis (diarrhea, abdominal cramps, and fever) to enteric fevers (including typhoid fever) which are life-threatening febrile systemic illness requiring prompt antibiotic therapy. Focal infections and an asymptomatic carrier state occur. The most common form of salmonellosis is a self-limited, uncomplicated gastroenteritis.

Mode of transmission: Typhoid infection occurs through feco oral route and spreads through consumption of contaminated water, beverages, fruits and vegetables or through close contact with infected persons, food and water becomes contaminated mainly due to poor sanitation/hygiene  and mixing of sewage with drinking water

Diagnosis: Accurate and timely diagnosis is very important to ensure proper treatment and preventing antimicrobial resistance. salmonella typhi can successfully be cultured from the blood specimen during first week of illness, or from stool and urine in later stages of the disease.

Limitations in diagnosis: Patient’s prior use of antibiotics as well as the volume of blood collected for the sample affects the accuracy of blood culture, culture of blood and bone marrow is expensive and requires trained staff to perform the test. 40 to 60 percent of typhoid cases are correctly identified due to the low levels of bacteria in the blood during illness

Prevention: Water should be treated/ boiled before use, vaccines are also available which doesn’t provide 100% protection but limits the severity of the disease process typhoid conjugate vaccine provides longer immunity

Treatment: Azithromycin and Carbapenems should be used ONLY to treat XDR/MDR cases


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