3.1.3 Fluoroquinolone resistance

Fluoroquinolone antimicrobials are available orally including for severe infections. They can be used for intracellular organisms – in particular, S. typhi against which many other antimicrobials are not effective as they are unable to enter the mammalian cell – and are a very useful class of antimicrobials. However, fluoroquinolone resistance among Gram-negative organisms is widespread and two pathogen-AMR combinations are listed in the WHO ‘high’ category for R&D priority: fluoroquinolone-resistant Salmonellae and Campylobacter species. Fluoroquinolone-resistant Shigella species are of ‘medium’ R&D priority. Resistance is mostly via modification of the antimicrobial target, as a result of one or more chromosomal mutations.

Figure 5 Healthy free-range pigs in Svaneti, Georgia

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Resistance to antimicrobials is less likely to occur in free-range animals like pigs and poultry than those reared in intensive and overcrowded environments where use of antibiotics is common.

Figure 5 Healthy free-range pigs in Svaneti, Georgia

Both fluoroquinolone-resistant Campylobacter and Salmonella infections are major zoonoses and there are few antimicrobial treatment options. The infections can easily be acquired from food of animal origin if food hygiene is not strictly applied. In contrast, fluoroquinolone-resistant Shigella infections are not acquired from food animals and in general, only affect humans and other primates. Reliance is on good hygiene and sanitation to prevent spread, so they are widespread in contexts where this is difficult to achieve.