Henry P. Godfrey

Piscirickettsia salmonis is a globally distributed aquatic bacterium and a component of the normal salmon microbiome. It has significant biological and economic impact on Chilean salmon aquaculture due to the highly fatal disease, piscirickettsiosis. Unsuccessful attempts to prevent and treat this disease have resulted in heavy use of antimicrobials with adverse effects on the aquatic environment and piscine and human health. Evidence suggests P. salmonis could be a bacterium with relative pathogenic potential on farmed salmonids and other fishes that triggers piscirickettsiosis under particular conditions in the salmon and its environment. Application of a damage-response framework analysis could define the steps from asymptomatic P. salmonis infection to symptomatic disease, help tailor improved approaches to disease prevention and management, and, in turn, help avoid heavy use of antimicrobials which have global effects on animal health, human health, and environmental biodiversity (the One Health concept).

Diego Rivera, an acclaimed Mexican painter active during the first half of the 20th century, painted multiple frescoes in Mexico and the United States. Some include depictions of bacteria, their interactions with human hosts, and processes related to microbiology and public health, including the microbial origin of life, diagnosis of infection, vaccine production, and immunization. Microbiological subjects in Rivera's murals at the Mexican Ministry of Health in Mexico City; the Detroit Institute of Art, Detroit; Rockefeller Center, New York/Palacio de Bellas Artes, Mexico City; Chapultepec Park, Mexico City; and the Institute of Social Security, Mexico City, span almost 25 years, from 1929 to 1953. Illustrating the successes of the application of microbiological discoveries and methods to public health and the prevention and treatment of infectious diseases, they benefited from Rivera's creativity in melding microbiology's unique technological and scientific aspects and public health elements with industrial and political components.

The exponential growth of aquaculture over the past 30 years has been accompanied by a parallel increase in the use of antimicrobials. This widespread use has had negative effects on animal, human and environmental health and affected the biodiversity of the environments where aquaculture takes place. Results showing these harmful effects have been resisted and made light of by the aquaculture industry and their scientific supporters through introduction of misunderstandings and misinterpretations of concepts developed in the evolution, genetics, and molecular epidemiology of antimicrobial resistance. We focus on a few of the most obvious scientific shortcomings and biases of two recent attempts to minimise the negative impacts of excessive antimicrobial use in Chilean salmon aquaculture on human and piscine health and on the environment. Such open debate is critical to timely implementation of effective regulation of antimicrobial usage in salmon aquaculture in Chile, if the negative local and worldwide impacts of this usage are to be avoided.

The annual incidence of Lyme disease, caused by tick-transmittedBorreliella burgdorferi, is estimated to be at least 476,000 cases in the United States and many more worldwide. Ten to 20% of antimicrobial-treated Lyme disease patients display posttreatment Lyme disease syndrome (PTLDS), a clinical complication whose etiology and pathogenesis remain uncertain.

Summary: Large amounts of antimicrobials are used in salmonid aquaculture in Chile. Most are used in marine aquaculture, but appreciable amounts are also employed in freshwater aquaculture. Much research and many publications have examined transferable antimicrobial resistance in bacteria isolated from marine salmon farms, but much less attention has been paid to this area in freshwater salmon farming. A recent paper by Domínguez et al . (2019) has as least in part remedied this situation. We now comment on some of its interpretations and have attempted to point out its areas of strength and weakness in light of the published scientific literature. Seen in this setting, the important results presented by Domínguez et al . (2019) underline the need for increased awareness of the challenge to animal and human health posed by excessive use of antimicrobials in aquaculture.

Ed. Note: The authors of the published article did not feel that a response was necessary. The interesting work by Shen et al. ([1][1]) discusses the pathogenicity of Aeromonas for freshwater fish in passing but does not mention that Aeromonas are not only pathogenic for freshwater fish but also

Summary: Infections with tick‐transmitted Borreliella ( Borrelia ) burgdorferi , the cause of Lyme disease, represent an increasingly large public health problem in North America and Europe. The ability of these spirochetes to maintain themselves for extended periods of time in their tick vectors and vertebrate reservoirs is crucial for continuance of the enzootic cycle as well as for the increasing exposure of humans to them. The stringent response mediated by the alarmone (p)ppGpp has been determined to be a master regulator in B . burgdorferi . It modulates the expression of identified and unidentified open reading frames needed to deal with and overcome the many nutritional stresses and other challenges faced by the spirochete in ticks and animal reservoirs. The metabolic and morphologic changes resulting from activation of the stringent response in B . burgdorferi may also be involved in the recently described non‐genetic phenotypic phenomenon of tolerance to otherwise lethal doses of antimicrobials and to other antimicrobial activities. It may thus constitute a linchpin in multiple aspects of infections with Lyme disease borrelia, providing a link between the micro‐ecological challenges of its enzootic life‐cycle and long‐term residence in the tissues of its animal reservoirs, with the evolutionary side effect of potential persistence in incidental human hosts.