Drug-resistant Intestinal Bug Spreads in US, CDC Reports

Public health officials in the US have reported a series of outbreaks of disease caused by the introduction of a multi-drug-resistant strain of the bacteria Shigella by international travelers.

The bacteria that cause shigellosis (nicknamed "traveler's diarrhea," "Montezuma's revenge," "Delhi belly," or the "Turkey trots") are found in water used for drinking, washing food, or irrigating crops, which had been contaminated by human or animal stools.

Shigellosis is the culprit responsible for nearly half a million annually reported cases of diarrhea in the US. The Centers for Disease Control and Prevention (CDC) recently reported that Shigella sonnei, the most common species of Shigella, infected 243 people in 32 states and Puerto Rico between May 2014 and February 2015.

The CDC also noted that nearly 90 percent of cases examined in Massachusetts, California, and Pennsylvania were caused by bacteria that were resistant to the antibiotic ciprofloxacin (Cipro) -- the primary drug choice for treating shigellosis among US adults.

Until recently, Cipro resistance was only found in around 2% of Shigella infections tested in the US.

Although many Shigella-infected individuals exhibited mild symptoms, the bug was still able to easily spread. The report cited that in these outbreaks, the bacteria “spread easily in childcare facilities and among homeless people and gay and bisexual men.”

CDC Director Tom Frieden, MD, commented, "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." According to Frieden, the US is moving quickly to put in place a national plan to curb antibiotic resistance, because "we can't take for granted that we'll always have the drugs we need to fight common infections."

While in the US most strains of Shigella are already resistant to the antibiotics ampicillin and trimethoprim/sulfamethoxazole, internationally Shigella has increasingly become resistant to Cipro.

The report describes how through the CDC's PulseNet lab network, it was possible to identify an increase in shigellosis cases caused by a unique strain of Cipro-resistant Shigella. About half of the cases were people known to have returned from the Dominican Republic, India, and other places outside the US.

The CDC recommended practical hygiene habits to aid in preventing the spread of Shigella:

· Wash hands frequently with soap and water

· Always wash hands with soap and water after using the toilet, and before preparing food and eating

· If your child is sick with diarrhea, keep them home and away from childcare and group activities

· Don't prepare food for others if you have diarrhea

· Avoid swimming pools and other public water places for a few weeks as you recover from a diarrhea illness.

Anna Bowen, MD, CDC's Waterborne Diseases Prevention Branch medical officer, and lead author of the report, remarked,“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.”

Prior research had long revealed drugs only killed bacteria, while simultaneously blocking certain gut immune functions.

However, researchers have recently discovered that antibiotic use —especially overuse – is correlated withan array of problems affecting the immune system, glucose metabolism, food digestion, gut health and behavior.