Hospital germs originated in North America

Resistant hospital germs originated in the USA: An international research team has analyzed the worldwide spread of the antibiotic-resistant hospital bacterium Clostridium difficile (C. difficile) and traced its origin back to North America. Infections with resistant Clostridium difficile hospital germs have become „Over the last decade, it has become the leading cause of antibiotic-associated diarrhea worldwide“ developed, the researchers report in the journal „Nature Genetics“.

10/12/2012

At an alarming rate, two antibiotic-resistant Clostridium difficile strains have spread to clinics around the world in recent years, the researchers around Miao He of „Wellcome Trust Sanger Institute“ in Cambridge, UK. Due to the resistance, the severe diarrheal diseases triggered by Clostridium difficile can hardly or only to a limited extent be treated. Thus, C. difficile in hospitals and nursing homes today is the main pathogen of sometimes life-threatening diarrheal diseases. In recent years, the bacteria have led to massive disease outbreaks in European and North American clinics. Where the pathogens come from and how they have spread, has remained unclear. The particularly severe waves of infection were often triggered by variants of the aggressive genotype 027 / BI / NAP1, the pathogens were resistant to the antibiotic class of fluoroquinolones, the scientists write in the journal „Nature Genetics“.

Two lines of antibiotic-resistant hospital germs emerged in parallel
The genome researchers now come to the conclusion that in North America almost simultaneously two resistant strains of the common hospital germ Clostridium difficile have developed. Subsequently, the germs spread rapidly in the global health system, so Miao He and colleagues on. The development of the resistances was presumably favored by the massive partial negligent use of antibiotics. Once formed, the two resistant C. difficile strains have spread to various routes in North America, the UK, continental Europe and Australia, the researchers report. In the individual states not infrequently massive nosocomial infections (hospital infections) and correspondingly severe disease waves were observed.

More than 300 samples of the hospital germ Clostridium difficile were analyzed
The genome researchers around Miao He came to the origin of the new resistant bacterial strains on the basis of 151 germ samples, which were isolated in clinics worldwide between the years 1985 and 2010, and another 188 samples from Great Britain on the track. The scientists created a pedigree of the pathogens based on the changes in the genome. Surprisingly, they found that two resistant C. difficile strains developed independently of each other in the US almost simultaneously. The two resistant lines of the genotype, which are immune to fluoroquinolones, thus emerged more or less in parallel. So far, the experts assumed that there is only one antibiotic-resistant line of the hospital germ.

Resistances due to excessive use of antibiotics
About ten years ago, according to the researchers, the first antibiotic-resistant C. difficile strain, FQR1, was produced in the USA. Within a few years, the hospital germ had triggered severe waves of infection in the clinics of several states and was subsequently introduced to South Korea and Switzerland. The second antibiotic-resistant line, FQR2, also developed, according to the findings of the genome researchers, probably in North America, but spread from here to Britain, Australia and at least four separate routes to continental Europe. As causes for the parallel emergence of the two antibiotic-resistant germ lines, the scientists suspect the excessive use of antibiotics. In the late 1990s and early 2000s, fluoroquinolones were the most commonly prescribed antibiotics in North America, increasing the selective pressure on the germs so that two resistant C. difficile variants could develop in parallel and then spread rapidly.

Symptoms of Clostridium difficile infection
Typical signs of infection with C. difficile are diarrhea, abdominal pain, intestinal inflammation and fever. At worst, the toxins of the pathogens lead to a life-threatening dissolution of the intestinal walls, after which the bacteria spread throughout the organism and can cause blood poisoning (sepsis). In this case, there is an acute danger to life for the patients. (Fp)

Read about:
Multi-resistant germs in the pigsty
Infections by germs in the Baltic Sea
With bacteria against hospital germs
Risk of infection in the hospital
Resistant bacteria in German hospitals

Picture: Dr. Karl Herrmann