Which antibiotics are least likely to cause superinfection?

Which antibiotics are least likely to cause superinfection?

• A. Narrow-spectrum such as Penicillin G
• B. Augmentin
• C. Macrolides
• D. Broad-spectrum tetracycline

Answer: (A)

The amount of disruption to normal body flora drives the risk of a superinfection. Narrow-spectrum antibiotics target a limited group of organisms and spare much of the harmless resident bacteria in places like the gut and mucosal surfaces. Because they don’t wipe out a broad swath of flora, there’s less opportunity for opportunistic organisms (like yeast or toxin-producing bacteria) to overgrow. A narrow-spectrum penicillin fits this pattern: it mainly hits certain Gram-positive bacteria and doesn’t broadely disrupt anaerobes and other flora, so it’s least likely to lead to a superinfection. In contrast, treatments that cover a wider range of organisms (including many anaerobes) disturb the normal flora more extensively, increasing the chances of secondary infections. Macrolides have broader coverage than the penicillin class but aren’t as disruptive as the most broad-spectrum agents, so they carry some risk but not as high as the very broad-spectrum options. Broad-spectrum tetracyclines disrupt a wide array of flora and are more prone to cause superinfections.

The amount of disruption to normal body flora drives the risk of a superinfection. Narrow-spectrum antibiotics target a limited group of organisms and spare much of the harmless resident bacteria in places like the gut and mucosal surfaces. Because they don’t wipe out a broad swath of flora, there’s less opportunity for opportunistic organisms (like yeast or toxin-producing bacteria) to overgrow. A narrow-spectrum penicillin fits this pattern: it mainly hits certain Gram-positive bacteria and doesn’t broadely disrupt anaerobes and other flora, so it’s least likely to lead to a superinfection.

In contrast, treatments that cover a wider range of organisms (including many anaerobes) disturb the normal flora more extensively, increasing the chances of secondary infections. Macrolides have broader coverage than the penicillin class but aren’t as disruptive as the most broad-spectrum agents, so they carry some risk but not as high as the very broad-spectrum options. Broad-spectrum tetracyclines disrupt a wide array of flora and are more prone to cause superinfections.