Stewardship / Resistance Scan for Jul 25, 2018

Antibiotic resistance in leeches
;
Candida auris uptick
;
MCR-1 on hospital surfaces

Study finds very low levels of antibiotics in leeches lead to resistance

Very low levels of antibiotics in the gut of leeches used in medicine are enough to promote antibiotic-resistant bacteria—and exposure to the leeches led to resistant infections in plastic surgery patients—an international group of researchers reported yesterday in mBio.

In 2011, plastic surgeons began reporting patients who had infections with Aeromonas bacteria resistant to the key antibiotic ciprofloxacin (Cipro). And at about the same time, University of Connecticut (UConn) microbiologist Joerg Graf, PhD, the senior author of the study, found that a strain of Aeromonas that usually thrives in leeches was not surviving well in their gut.

Graf and his team analyzed the medicinal leeches, which are used to reduce swelling in plastic surgery patients. They found, according to Graf, "Without ever having been in a hospital, without having seen a patient, these leeches contained Cipro-resistant bacteria." But the amount of antibiotic present in the leeches was extremely low, about 0.01 micrograms (mcg) per milliliter (mL), 400 times less than the concentration a bacteria must survive in order to be considered "resistant," according to a UConn news release.

The researchers traced the presence of the antibiotic to poultry blood on which the leeches had fed.

To determine whether such low levels of ciprofloxacin were truly causing antibiotic resistance, the scientists sequenced the genomes of Aeromonas from leeches contaminated with antibiotics. They found that they contained the three bits of DNA necessary for resistance to ciprofloxacin.

In addition, when the ciprofloxacin-resistant Aeromonas were grown alongside a test strain of Aeromonas in a clean lab medium or inside a leech, the test strain grew all over them. But if there was even a tiny bit of antibiotic added into the mix, as low as 0.01 mcg/mL, the ciprofloxacin-resistant strain dominated.
Jul 24 mBio study
Jul 24 UConn news release

 

CDC reports uptick in Candida auris cases

The United States now has 340 confirmed cases of Candida auris, according to an updated case count from the Centers for Disease Control and Prevention (CDC). While the total case count remains fairly low, it's risen by 29 since May and nearly doubled since November 2017.

As of Jun 30, infections by the multidrug-resistant fungus have been identified in healthcare facilities in 11 states, with most cases reported in New York (196), New Jersey (79), and Illinois (46). Cases have also been reported in Massachusetts (7), Florida (3), Maryland (3), Oklahoma (2), California (1), Connecticut (1), Indiana (1), and Texas (1). All cases represent laboratory-confirmed C auris infections, with an additional 29 cases are listed as probable, 22 of them in New Jersey.

The CDC also said that 643 patients have been found to be colonized with C auris, detected through targeted screening in four states reporting clinical cases. The screening is being conducted as part of an effort to control the spread of the pathogen, which can persist on surfaces in healthcare facilities and spread between patients.

In patients with compromised immune systems, C auris can cause serious invasive infections affecting the bloodstream, heart, brain, ear, and bones. More than 1 in 3 patients with invasive C auris infections die. The fungus, which was originally reported in Japan in 2009, has shown resistance to the three major classes of antifungal drugs used to treat Candida infections.

C auris cases have been reported in 30 countries.
Jul 23 CDC case count update

 

Study: Italian hospital surfaces harbor MCR-1 genes

A new study shows that 8.3% of tested surfaces in eight Italian hospitals harbor the MCR-1 gene, which confers resistance to colistin, an antibiotic of last resort. The research is published in Emerging Infectious Diseases.

Researchers conducted the study in an effort to establish the diffusion of the MCR-1 gene in healthcare settings. They collected 300 surface samples from the hospitals in 2016 and 2017, from the floor, bed footboard, and sink. A total of 25 (8.3%) of the samples had pathogens containing the MCR-1 gene.

"Identification results indicated that different species harbored the mcr-1 gene, including [Klebsiella] pneumoniae, K. oxytoca, [Escherichia] coli, Acinetobacter Iwoffii, Enterobacter cloacae, E. agglomerans, Citrobacter freundii, Pseudomonas aeruginosa, and P. putida. These results suggest that this gene is silently spreading to many gram-negative bacteria responsible for infections in the clinical settings," the authors said.

MCR-1-associated colistin resistance was first reported in Italy in 2015, in an Escherichia coli strain. The gene is found in approximately 10% of animal isolates and in 0.1% to 2% of human isolates globally, the authors wrote.

This study suggests hospital surfaces represent a possible reservoir of serious antibiotic-resistant nosocomial pathogens.
Jul 23 Emerg Infect Dis study  

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