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"Super Bacteria" at the Rio Olympics: A Cause for Concern?


Marina da Glória- venue for the Olympics sailing competition.
Caleb Paine, a 25 year old sailor from San Diego, CA, will be competing at his first Olympics in Rio de Janeiro in the Finn sailing competition. He will face some stiff competition from sailors hailing from around the world, but he and his fellow competitors may not only be concerned about winning the gold medal next month when they hit the water at Marina da Glória- the venue for the sailing event.
They may also be concerned about super bacteria.
Amid concerns surrounding the Rio Olympics- namely issues related to public safety and the recent outbreak of the Zika virus in Brazil, now there’s widespread news in the media reporting “super bacteria” being detected in Rio waters, near where the open water events are scheduled to take place1.
Sanitation conditions of the waterways and beaches in Rio have previously raised concerns, as it is known to take in municipal sewage coming from the nearby communities. From his recent training visit to Rio, German Paralympic sailor Heiko Kröger explained, “It’s a nice sailing area but every time you get some water in your face, it feels like there's some alien enemy entering your face... I keep my nose and my lips closed.” One of his teammates also had a severe skin infection after the training trip, and he believes that this was caused by the super bugs.
So the waters in Rio de Janeiro sound pretty nasty. But what exactly did they find in the water?
These reports stem from a recent paper2 published in the journal Antimicrobial Agents and Chemotherapy this past May by a group of researchers based in Rio de Janeiro. For this study, this group took water samples from 9 different locations along the Carioca River (which flows into Marina da Glória) and the Rodrigo de Freitas Lagoon- where the Olympic canoe/kayak events are scheduled to take place. Of the 9 locations, researchers were able to isolate bacteria that were resistant to ceftazidime and ertapenem- two types of antibiotics, in 4 of them. All 4 of these locations were along the Carioca River, and not from the samples taken from the Rodrigo de Freitas lagoon (breathe easy now, canoers).
Carioca River- where it flows into Flamengo Beach. Photo: Ricardo Borges/Folhapress
Upon further genetic analysis for antibiotic resistant genes, the group identified several strains carrying exogenous genes that encode for carbapenemases. These are enzymes that are responsible for hydrolyzing β-lactams, which comprise the majority of effective antibiotics, including penicillins, cephalosporins, monobactams, and carbapenems that inhibit cell wall synthesis in bacteria. Because of this broad-spectrum activity against β-lactams, carbapenemases are also referred to as β-lactamases. These genes usually transfer from one bacteria to another via the transmission of plasmids encoding for these genes between microbes residing in the same environment. As carbapenems have been referred to as the “last resort” of anti-microbial treatments, infections involving carbapenemase-carrying bacteria is extremely difficult to treat in the clinic, with only minimal effects when treated by some other class of antimicrobials, such as tetracycline. Efforts have been raised to counteract the presence of these genes in bacteria by treating them with β-lactamase inhibitors, such as Tebipenem and Sulbactam, in attempts to re-sensitize microbes to β-lactams, but the rapid evolution of carbapenemase genes allowed the bacteria to become immune to these inhibitors and have rendered them virtually ineffective. As featured in one of our previous blog posts, the rise of multidrug-resistant bacteria resulted from repeated selection processes via the exposure to a variety of antibiotics in their environment. This is especially a problem in hospitals, where there is more widespread antibiotic use in a confined environment.
Of interest, there were two particular carbapenemase-carrying strains of bacteria identified in the study: Enterobacter cloacae (E. cloacae), and Klebsiella pneumoniae (K. pneumoniae). Both E. cloacae and K. pneumoniae are both found as natural flora in the gut, and K. pneumoniae is also a typical resident in the mouth and skin. Pathological infections involving these two classes of microbes are rare in healthy adults; most of these cases are nosocomial infections - those that occur at hospitals in patients with weakened immune systems. Infections involving Carbapenemase-Resistant Enterobacters (CRE) often occur in patients getting infected during organ transplants, and immunocompromised patients who experience extended stays at the hospital.
Carbapenemase-Resistant K. pneumoniae (CRKP) infections commonly infect hospital patients utilizing contaminated ventilators and respirators, which allows CRKP to enter patients’ lungs. Once inside, CRKPs adhere to lung epithelial cells using Capsular Polysaccharide (CPS) expressed on their surface. Epithelial cells in immune-proficient individuals would normally upregulate pro-inflammatory signals to recruit neutrophils to the adhesion site and clear out invading CRKPs. However, in patients with weakened immune systems, CRKPs won’t be cleared out normally and can colonize. Once colonized, they can cause bloody sputum and, in the worst cases, eventually invade the bloodstream to cause systemic infection.
Scanning electron micrograph of Klebsiella pneumoniae.
Photo: Janis Carr/CDC
This all sounds scary, but it must be noted that the actual number of CRE and CRKP microbes detected in the water samples in this study were extremely small (the experimental setup also selectively isolated microbes specifically carrying carbapenemases, too). Also, the risk of healthy adults getting infected by these bugs is very minimal, and no carbapenemase- carrying bacteria were detected directly in the areas where the Olympic events are scheduled to take place. Overall, hardy water sport athletes like Caleb, who are healthy adults amongst other Olympic competitors, probably won’t have to lose sleep at night worrying about getting infected by untreatable super bugs. For the athletes competing in the open Rio waters this August, Dr. William Schaffner, an infectious diseases specialist at Vanderbilt University, does have one line of expert advice:
“...as soon as they get out of the water, [they] should take a shower with soap and water.”
Are you an expert in antibiotic-resistant bacteria? Cheering for athletes like Caleb this summer at the Olympic games in Rio? Contact us at tech@biolegend.com!

Olympic US sailing team member Caleb Paine.
Photo: Jen Edney/US Sailing
References:
  1. ‘Super bacteria’ discovered in Rio’s waters as Olympics near
  2. Detection of carbapenemases genes on aquatic environment in Rio de Janeiro, Brazil
  3. Neutrophil Recruitment to the Lungs during Bacterial Pneumonia
  4. Carbapenem-Resistant Enterobacteriaceae: Epidemiology and Prevention
  5. ‘Superbug’ found in Rio bay not likely to cause infection
Contributed by Kenta Yamamoto, PhD.
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