International travelers are bringing a multidrug-resistant
intestinal illness to the United States and
spreading it to others who have not traveled,
according to a report released today by the Centers
for Disease Control and Prevention (CDC). Shigella
sonnei bacteria resistant to the antibiotic
ciprofloxacin sickened 243 people in 32 states and
Puerto Rico between May 2014 and February 2015.
Research by the CDC found that the drug-resistant
illness was being repeatedly introduced as ill
travelers returned and was then infecting other
people in a series of outbreaks around the country.
Drug-resistant Shigella - Centers for Disease
Control and Prevention
Shigellosis is an infectious disease caused by a
group of bacteria called Shigella. Most who are
infected with Shigella develop diarrhea, fever, and
stomach cramps starting a day or two after they are
exposed to the bacteria. Shigellosis usually
resolves in 5 to 7 days. Some people who are
infected may have no symptoms at all, but may still
pass the Shigella bacteria to others. The spread of
Shigella can be stopped by frequent and careful
handwashing with soap and taking other hygiene
measures.
CDC and public health partners investigated several
recent clusters of shigellosis in Massachusetts,
California and Pennsylvania and found that nearly 90
percent of the cases tested were resistant to
ciprofloxacin (Cipro), the first choice to treat
shigellosis among adults in the United States.
Shigellosis can spread very quickly in groups like
children in childcare facilities, homeless people
and gay and bisexual men, as occurred in these
outbreaks.
“These outbreaks show a troubling trend in Shigella
infections in the United States,” said CDC Director
Tom Frieden, M.D., M.P.H. “Drug-resistant infections
are harder to treat and because Shigella spreads so
easily between people, the potential for more – and
larger – outbreaks is a real concern. We’re moving
quickly to implement a national strategy to curb
antibiotic resistance because we can’t take for
granted that we’ll always have the drugs we need to
fight common infections.”
In the United States, most Shigella is already
resistant to the antibiotics ampicillin and
trimethoprim/sulfamethoxazole. Globally, Shigella
resistance to Cipro is increasing. Cipro is often
prescribed to people who travel internationally, in
case they develop diarrhea while out of the United
States. More study is needed to determine what role,
if any, the use of antibiotics during travel may
have in increasing the risk of antibiotic-resistant
diarrhea infections among returned travelers.
“The increase in drug-resistant Shigella makes it
even more critical to prevent shigellosis from
spreading,” said Anna Bowen, M.D., M.P.H., a medical
officer in CDC’s Waterborne Diseases Prevention
Branch and lead author of the study. “Washing your
hands with soap and water is important for everyone.
Also, international travelers can protect themselves
by choosing hot foods and drinking only from sealed
containers.”
CDC’s PulseNet lab network identified an increase in
Shigella sonnei infections with an uncommon genetic
fingerprint in December 2014. Further testing at
CDC’s National Antimicrobial Resistance Monitoring
System (NARMS) lab found that the bacteria were
resistant to Cipro. PulseNet detected several large
clusters: 45 cases in Massachusetts; 25 cases in
California; and 18 cases in Pennsylvania. About half
of the PulseNet cases with patient information were
associated with international travel, mostly to the
Dominican Republic and India. The San Francisco
Department of Public Health reported another 95
cases (nine of them among those identified by
PulseNet), with almost half occurring among the
homeless or people living in single-room occupancy
hotels.
Shigella causes an estimated 500,000 cases of
diarrhea in the United States every year. It spreads
easily and rapidly from person to person and through
contaminated food and recreational water. It can
cause watery or bloody diarrhea, abdominal pain,
fever, and malaise. Although diarrhea caused by
Shigella typically goes away without treatment,
people with mild illnesses are often treated with
antibiotics to stop the diarrhea faster. Until
recently, Cipro resistance has occurred in just 2
percent of Shigella infections tested in the United
States, but was found in 90 percent of samples
tested in the recent clusters.
Because Cipro-resistant Shigella is spreading, CDC
recommends doctors use lab tests to determine which
antibiotics will effectively treat shigellosis.
Doctors and patients should consider carefully
whether an infection requires antibiotics at all.
To prevent the spread of shigellosis, CDC recommends
that people wash their hands often with soap and
water, especially after using the toilet and before
preparing food or eating; keep children home from
childcare and other group activities while they are
sick with diarrhea; avoid preparing food for others
while ill with diarrhea; and avoid swimming for a
few weeks after recovering. Improving access to
toilets and soap and water for washing hands may
help prevent Shigella transmission among the
homeless.
Travelers to developing countries can take
additional precautions to avoid diarrhea and
minimize infection with resistant bacteria. Choose
safe foods and beverages, such as food that is
steaming hot and drinks from sealed containers
(download CDC’s app “Can I Eat This?” to help you
make safer food and beverage choices when you
travel). Wash hands frequently, particularly before
eating and after using the toilet. Take bismuth
subsalicylate to prevent travelers’ diarrhea and
treat it with over-the-counter drugs like bismuth
subsalicylate or loperamide. Try to reserve
antibiotics for severe cases of travelers’ diarrhea.
Health care providers should test stool samples from
patients with symptoms consistent with shigellosis,
re-test stool if patients do not improve after
taking antibiotics, and test bacteria for antibiotic
resistance.
For more information
http://www.cdc.gov/shigella/
Travelers can learn more about food and water
precautions to prevent Shigella at:
http://wwwnc.cdc.gov/travel/yellowbook/2014/chapter-2-the-pre-travel-consultation/food-and-water-precautions.
U.S. Department of Health & Human Services
FoodSafety.gov
WHO - World Helath Organisation
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