An Apple a Day
An Apple a Day
[Megan is facing straight out of a slim panel as she stands behind a lectern addressing the reader.] Megan: An apple a day keeps the doctor away. Megan: Or at least, it used to.
[The comic zooms out revealing that Megan and the lectern are standing on a podium. Megan is pointing behind her, with a stick, to at a poster prominently featuring Doctor Ponytail with three apples over her head.] Megan: Over time, some doctors have developed a resistance to apples. Keeping them away takes two or three apples instead of one. Megan: And there are worrying signs that a few doctors may have become completely immune.
[The comic zooms in again on Megan behind the lectern.] Megan: So we must stockpile our finest apples in reserve, using them to fend off only the very worst doctors. Megan: Honeycrisps still work on most of them, but we don't know for how long.

" An apple a day keeps the doctor away " is a common English proverb and rhyme . The suggestion is that eating one apple daily will keep you healthy, and therefore reduce your necessity to go to the doctor or, more literally, to have the doctor come to you as was likely the case when this proverb was first used.
Megan is giving a talk, starting with the common proverb, before continuing with "At least, it used to." In a normal scenario, this might have been to imply that eating apples is no longer enough to stay healthy. However, in this comic, this expression is reinterpreted to mean that an apple used to repel a doctor. It also suggests that keeping doctors away is of great importance, presumably because doctors in this scenario are undesirable. The method of action of apples is not specified; they could act as repellents, analogous to insect repellent , or possibly as lethal agents, as antibiotics are to bacteria , or fungicides are to fungi .
Megan continues with her reinterpretation, mentioning that doctors have become resistant to apples so two or even three may be needed. As control agents become more widely used, organisms which are less sensitive to the control may become more common, as is happening with mosquitoes becoming insensitive to repellents , or antimicrobial resistance , and pesticide resistance .  Such resistant organisms may require higher doses, or use of multiple control agents.
In the worst cases, doctors have become completely immune to apples (i.e., superbugs ). A poster behind Megan shows Doctor Ponytail with three apples above her. Megan advocates using the 'finest' apples only in these cases (a reference to multidrug-resistant pathogens , where some antibiotics are only used as a last-resort to reduce the development of resistance to them).
This comic is a clear reference to the overuse of antibiotics in modern society, leading to an increase in antimicrobial resistance ("Superbugs"), which has seen increasing awareness in the last few years. The World Health Organization had the first Antibiotic Awareness Week in 2015, where a talk similar to the one in the comic would seem appropriate.  Similar problems occur in growing plants, where various pests (whether insect, fungi, microbes, or plants) adapt to control measures, making control less effective.
In the title text, this is taken further: "Gran-negative" is a pun on Gram-negative , a category of bacteria. A well-known technique called Gram staining distinguishes two classes of bacteria (Gram positive versus Gram negative) on the basis of properties of their cell walls. In this case, Granny Smith apples are supposedly effective against Gran-positive doctors (since the name begins with "Gran"), making them ineffective against new Gran-negative doctors.
Honeycrisp and Granny Smith are two different cultivars of apples. Granny Smith apples are a refreshingly tart green apple, which have mixed reviews among apple eaters. Conversely, Honeycrisp are a very sweet apple, considered by some to be "an ideal apple for eating raw", and is the state fruit of Minnesota.
[Megan is facing straight out of a slim panel as she stands behind a lectern addressing the reader.] Megan: An apple a day keeps the doctor away. Megan: Or at least, it used to.
[The comic zooms out revealing that Megan and the lectern are standing on a podium. Megan is pointing behind her, with a stick, to at a poster prominently featuring Doctor Ponytail with three apples over her head.] Megan: Over time, some doctors have developed a resistance to apples. Keeping them away takes two or three apples instead of one. Megan: And there are worrying signs that a few doctors may have become completely immune.
[The comic zooms in again on Megan behind the lectern.] Megan: So we must stockpile our finest apples in reserve, using them to fend off only the very worst doctors. Megan: Honeycrisps still work on most of them, but we don't know for how long.
