Study finds 'alarming' levels of drug-resistant Salmonella in Pakistan

News brief

Pakistani kids getting clean water — USAID / Flickr cc

A systematic review and meta-analysis has found alarming levels of antibiotic-resistant Salmonella in Pakistan, researchers reported yesterday in Open Forum Infectious Diseases.

The review, led by researchers at the University of Peshawar, analyzed 31 studies with data on antibiotic susceptibility in human isolates of Salmonella Typhi and Salmonella Paratyphi, both of which enter the body through contaminated food and water and are the leading causes of typhoid and paratyphoid fever. While drug-resistant Salmonella is considered a global public health priority by the World Health Organization, Pakistan has emerged in recent years as a hot spot for multidrug and extensively drug-resistant (MDR and XDR) S Typhi.

Significant resistance to commonly used antibiotics

The data from the 31 studies revealed significant resistance rates to commonly used antibiotics for S Typhi, including nalidixic acid (92%; 95% confidence interval [CI], 88% to 95%), ampicillin (80%; 95% CI, 66% to 89%), ciprofloxacin (64%; 95% CI, 48% to 77%), azithromycin (7%; 95% CI, 3% to 16%), and meropenem (2%; 95% CI, 1% to 3%), with notable variations across different cities. Resistance rates were similarly high for S paratyphi: Nalidixic acid (91%; 95% CI, 82% to 96%), ampicillin (34%; 95% CI, 21% to 50%), ciprofloxacin (51%; 95% CI, 25% to 77%), azithromycin (4%; 95% CI, 1% to 12%), and meropenem (2%; 95% CI, 1% to 5%).

In S typhi, 29% and 25% of patients were found to have MDR and XDR isolates, respectively, while 9% of patients had MDR S paratyphi infections and 2% had XDR.

The study authors say the findings underscore the urgent need for updated treatment guidelines and public health strategies in Pakistan, which has the third-highest typhoid fever rate in the world.

"Vaccination, improved access to clean water and sanitation, and the rational use of antibiotics are critical components of the public health response to this increasing threat," they wrote. "Continued studies, policy interventions, and national and international cooperation are essential to safeguard public health and ensure the effective management of enteric fever in Pakistan and beyond."

Washtenaw becomes Michigan's 15th county with CWD-positive wild deer

News brief

Mary Van Beusekom, MS

Washtenaw County white-tailed buck — Tidewater Teddy / Flickr cc

Today, the Michigan Department of Natural Resources (DNR) reported a case of chronic wasting disease (CWD) in Washtenaw County, making it the state's 15th county in which the fatal neurologic disease has been found in free-ranging deer.

The buck had been seen acting ill in Salem Township. Washtenaw County is in the southeastern part of Michigan's Lower Peninsula and is home to Ann Arbor.

"Prior to focused CWD surveillance in Washtenaw County, voluntary sampling between 2016 and 2019 resulted in 824 deer tested," the DNR said in a news release. "In 2021 and 2022, focused CWD surveillance efforts were conducted to gather additional samples, and 875 more deer were tested."

Thirty-nine deer in neighboring Jackson County have tested positive for CWD through combined DNR collections and hunter submissions to the Michigan State University Veterinary Diagnostic Laboratory, the DNR said.

The expansion of chronic wasting disease to Washtenaw County is consistent with the slow spread we've seen throughout Michigan.

Chad Fedewa, MS

CWD has also been detected in free-ranging deer in Clinton, Dickinson, Eaton, Gratiot, Hillsdale, Ingham, Ionia, Isabella, Jackson, Kent, Mecosta, Midland, Montcalm. and Ogemaw counties.

"The expansion of chronic wasting disease to Washtenaw County is consistent with the slow spread we've seen throughout Michigan," said Chad Fedewa, MS, acting DNR deer, elk and moose management specialist. "This case was identified thanks to a resident who saw a deer that appeared ill and reported it to us. Every piece of data is valuable in helping us make science-based decisions to support Michigan's wildlife."

Michigan's testing strategy

Michigan's CWD surveillance program tests deer in a group of counties each year and then rotates to another group. In 2021 and 2022, the DNR focused on the southwestern and southeastern Lower Peninsula, shifting to the northern Lower Peninsula in 2023 and parts of both the northern Lower Peninsula and the Upper Peninsula in 2024. Once all 2024 samples are processed, the DNR will identify counties in need of additional CWD testing in 2025.

CWD, which affects cervids such as deer, moose, and elk, is caused by infectious misfolded proteins called prions. The disease can spread through direct contact or contamination of the environment, where prions can persist for years.