strains resistant to antibiotics are on the rise – breaking latest news

Little is heard of Shigella, but it is one of the bacteria that the World Health Organization has included in the ranking of the most dangerous for humans. a Gram-negative and belongs to the family of Enterobacteriaceae (such as Escherichia coli): can cause an intestinal disorder called shigellosis or bacillary dysentery, characterized by diarrhoea, abdominal pain and severe dehydration. Sometimes treatment is needed, but the disease is rarely fatal; the risk for elevated in immunosuppressed or frail individuals (including infants and the elderly). The infection can be contracted from contaminated food and water and favored among other things by poor hand cleaning. It is important to pay attention to what you eat and drink, especially when traveling abroad. For the treatment of severe forms of shigellosis five antibiotics are availablebut in recent months strains resistant to all five are on the rise. The alert comes from the United States: superbugs have been found in 29 states, experts have declared Centers for disease control and prevention (Cdc) al New York Times, but they are probably even more widespread. The first case of resistant Shigella was discovered in the US in 2016; in 2022, these strains accounted for 5% of Shigella infections.

Characteristics of the infection it’s watery stools (sometimes with blood and mucus, due to inflammation affecting the intestines), nausea, stomach cramps and fever. Most shigellosis resolves within a few days with rest and plenty of hydration. If symptoms last more than a week or signs of severe dehydration, such as light-headedness or confusion, you should see a doctor. Five antibiotics are mainly used for the treatment of Shigella: azithromycin, ciprofloxacin, ceftriaxone, sulfamethoxazole + trimethoprim and ampicillin. It is not uncommon for some strains of the bacterium to fail to respond to one or two of these drugs, but resistance to all five is new. There are other drugs that could theoretically work, but they haven’t been tested yet. Consequentially there is currently no recommended treatment option for drug resistant strains. This is not “pan-resistance” (which occurs when a bacterial strain is resistant to everything, with no more therapeutic options), but we have gone beyond the boundaries of what has been studied for Shigella, said Louise Francois Watkins, a CDC physician.

According to the CDC Approximately 450,000 cases of shigellosis occur in the United States each yearof which approximately 6,400 require hospitalization. Most infections affect children under the age of 5but for still unclear reasons, the cases of resistance to drugs mainly concern adults, with a clear prevalence in some specific categories: men who have sex with other men, people who live without a fixed abode and subjects infected with Hiv. Shigella spreads very easily, because a minimum amount of bacteria is enough (which from feces come into contact with the nose or mouth) to trigger the disease. The most common routes of transmission are unwashed hands, sexual activity and contaminated food (Most often foodborne transmission is due to an infected person preparing or serving a meal, not the presence of Shigella in food). To limit the spread of the essential bacterium practice good hand hygienewashing with soap and warm water for at least 20 seconds after using the bathroom (or changing a baby’s diaper), before preparing food, and before and after sex. CDC experts advise anyone with diarrhea to avoid swimming pools and abstain from sexual intercourse for two weeks following illness.

The problem of bacteria resistant to antibiotics is dramatic, even in Italy. Microbes sensitive to drugs die, while those that evolved to evade them survive and spread. The more we use antibiotics, the more resistant the bacteria become: a sort of inevitable evolutionary process – explained al New York Times Stephen Baker, Professor of Molecular Microbiology at Cambridge University —. quite common that, once this path has been taken, resistant organisms are selected and therefore take over very quickly. Bacteria can acquire drug resistance through random mutations of their DNA or by swapping genes with other strains or species. Shigella is particularly good at picking up new genes, so antibiotic resistance in this bacterium often emerges. But gene sharing goes both ways. Resistance can spread to other organisms. So what we’re seeing now in Shigella is resistance, something we might see in other types of bacteria like E. coli or salmonella in the future, Watkins said. Shigella maybe an early warning sign of selective pressures that are also acting on other bacteria.

Not even Europe immune from the outbreak. Since September some European Union countries – as well as the United Kingdom and the United States – have reported an increase in cases of food poisoning caused by Shigella sonnei (there are several species of Shigella), between travelers returning from Cape Verde (Africa). The reports intensified in the months of November and December and in February, the European Center for Disease Prevention and Control (ECDC) published a Rapid risk assessment. As of February 16, ten European countries (Italy is not in the list), the United Kingdom and the United States had signaled 258 almost (221 confirmed and 37 classified as possible). Most of the strains of S. sonnei, responsible for the outbreak, appear resistant to the antibiotics trimethoprim and streptomycin, but single strains with resistance profiles to multiple antibiotics have been isolated. Many of the infected patients had stayed in the Santa Maria region, on the island of Sal, which is part of the Cape Verde archipelago.

There are four species of Shigella bacteria: S. sonnei, S. flexneri, S. boydii, and S. dysenteriae. Symptoms and possible complications depend on the species of bacteria causing the infection.
S. sonnei: The most common symptoms are diarrhea (sometimes bloody), abdominal pain and cramps, and fever. Nausea and/or vomiting, loss of appetite, headache or malaise may also occur.
S. flexneri: Causes diarrhea, pain, abdominal cramps, and fever, but is often more serious than S. sonnei infection. Inflammation and ulceration of the lower intestine is also common, and the disease can be prolonged and more severe.
S. boydii: can cause diarrheal diseases of varying severity, but mostly similar to those caused by S. sonnei.
St. dysentery: This species causes more severe disease than other forms of Shigella, with higher mortality rates. In most cases, inflammation and ulceration of the lower intestine occurs, which is manifested by bloody stools.
The complications of S. flexneri may include reactive arthritis and Reiter’s syndrome (inflammation of the urethra, conjunctivitis, and inflammation of the joints); S. dysenteriae can cause, in severe cases, an enlarged colon due to toxins, haemolytic uraemic syndrome, a type of kidney failure, blood clots, and sepsis.
Currently there is no vaccine to prevent Shigella infection.