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Vancomycin-resistant Enterococcus faecium (VRE) is spreading globally. Tytgat et al. (p. 5756–5762) shed light on the molecular mechanism underlying the successful clinical application of the probiotic Lactobacillus rhamnosus GG in sustained eradication of VRE. E. faecium and L. rhamnosus GG express mucus-binding pili that are remarkably similar sequentially, functionally, and immunologically. Exploration of the ability of L. rhamnosus GG and its pilins to compete with VRE in mucus attachment underpins their potential use as prophylactic and curative agents. These results provide molecular evidence for a novel probiotic mechanism involving interference with host binding of a potential pathogen.
Staphylococcal bacteriophages belonging to the genus Twortlikevirus are regarded as ideal candidates for clinical application to Staphylococcus aureus due to the emergence of antibiotic-resistant bacteria in that species. Takeuchi et al. (p. 5763–5774) isolated the virulent staphylococcal phage ΦSA012, which exerts lytic effects on a wide range of S. aureus isolates from bovine mastitis. The details of the host recognition mechanism of ΦSA012 will allow the analysis of the mechanisms of infection and expansion of the utility of staphylococcal Twort-like phages in the control of S. aureus.
Bacterial spores are notorious for their contamination of medical and food settings. Cold atmospheric plasma (CAP) shows great promise in the inactivation of spores. However, knowledge about spore properties after plasma treatment is limited. Using a single-cell technique, Wang et al. (p. 5775–5784) analyzed the physiological changes of multiple individual bacterial spores that were treated by a planar CAP device with different parameters. The work sheds light on the mechanism(s) of spore inactivation by CAP and will aid in developing more-effective and more-efficient plasma sterilization techniques for various applications.
Clostridium difficile, a main cause of healthcare-associated diarrhea in adults, is commonly found in asymptomatic infants. Kubota and colleagues (p. 5806–5814) examined stool specimens periodically collected from 111 healthy infants in Belgium to better understand the mode of carriage of toxigenic C. difficile. They revealed that considerable numbers of toxigenic C. difficile bacteria colonized infants' intestines and that the genotypes of these isolates were the same as those of isolates frequently identified in adult C. difficile diarrhea patients. Effective control of potentially pathogenic strains in infants may lead to the prevention of C. difficile diarrhea in adults.
Although humans have caught many deadly infections from animals, sometimes it happens the other way around. Using bacterial whole-genome sequencing, Senghore et al. (p. 5910–5917) showed that green monkeys in The Gambia have acquired Staphylococcus aureus from humans on more than one occasion. One bacterial lineage appears to have spread from humans to monkeys over 2,000 years ago, while two additional transfers have occurred in recent decades. As humans encroach on natural ecosystems, there is an increased risk of pathogens being transmitted from humans to animals or vice versa.
An understanding of the bacterial ecology of periodontal disease is important for diagnosis and treatment. Using almost 1,000 gum line swab specimens from Malawian women, Shaw et al. (p. 6057–6067) have quantitatively modeled associations between bacterial taxa and periodontal disease, separating signals associated with periodontitis (deepened dental pockets) from those associated with gingivitis (bleeding gums). This work supports a more complex disease model for periodontitis than a simple linear progression from gingivitis. Species involved in biofilm coaggregation were determined to be central members of a network of periodontitis-associated bacteria, showing that supragingival sampling can reveal important ecological relationships in periodontal disease.