[Question #14046] Syphilis w/ antibiotic interference

1 months ago

Potential exposure: July 12, 2024 (handjob with heavy saliva exposure; no oral sex). Abx were coincidental for sinus/congestion.

Timeline:

Aug 6: Amox-clav x7 days
Sept 4: Negative CIA
Sept 18-Oct 6: Painless oral sores
Oct 2: Negative RPR, slight elevated ast/alt
Oct 14: Azithromycin
Nov 19: Azithromycin
Nov 22: Wife (pregnant) negative CIA
Nov 24: Wife cefdinir
Dec 12: Wife amox-clav
Dec 18: My negative RPR, slightly enlarged liver with gallbladder sludge.
Jan 10, 2025: Wife negative RPR at delivery
Jan 2025: Doxycycline for me
May 19, 2026: My negative CIA

Other findings after exposure: white groin/ankle patches resembling leukoderma/vitiligo, slight patchy hair thinning, foot rash, and hand rash(top of hand) on me. My son dropped from ~44th percentile birth weight to ~3rd-5th percentile by 6 months and had a transient rash in infancy.

Main concern: Could antibiotic use have partially treated syphilis and delayed/prevented serologic positivity?

Questions:

How likely is antibiotic interference in this scenario?
How reliable is a negative CIA nearly 2 years later?
How realistic is congenital syphilis given my wife's negative CIA during pregnancy and negative RPR at delivery given antibiotic use?

1 months ago

I was hoping dr. Hook would take a look as i read about studies he did

H. Hunter Handsfield, MD

1 months ago

Welcome to the forum and thanks for your question. Users do not have the privilege of requesting the moderator who responds. However, I can assure you that Dr. Hook's and my STD knowledge in general, and in this case about syphilis, is essentially the same. I guarantee his responses would be the same as mine.

There is no such thing as antibiotic "interference" with syphilis diagnosis except by curing the infection. That is, no antibiotics suppress syphilis and result in negative blood tests with the infection persisting. In addition, there has never been a case of syphilis or of Treponema pallidum (the syphilis bacteria) that was resistant to amoxicillin (or amoxicillin/clav), to doxycycline, or (probably) cefdinir. Some strains are resistant to azithromycin, however. But most important, it is not possible to have syphilis of more than a few weeks duration and to have the negative blood test test results you report for you or your wife. What symptoms you or she have now or in the future do not matter at all: the ones you report don't sound like syphilis, but even if they were entirely typical, the test result prove syphilis isn't he cause.

Those comments cover your numbered questions, but to be explicit to assure no misunderstanding:

1. Zero likelihood. There is no such thing, as in my comment above.

2. 100% reliable regardless of these or any other antibiotics.

3. Completely unrealistic: no possibility at all.

I hope these comments are helpful. Let me know if anything isn't clear.

HHH, MD

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1 months ago

Thank you that is helpful. A few things below if you wouldnt mind.

1. I know that my exposure also was either no or extremely low risk even with an infected partner(handjob with heavy saliva) from what ive read but the symptoms really had me thinking twice. Is that true even with the studies i read about with saliva containing syphilis dna?

2. I read about partial treatment and it could potentially delay positive results due to antibody response blunting though so im still confused/curious about what that means exactly. Ive read that on this forum and in studies i thought.

3. For the antibiotics, i thought that amoxicillin would not cure in that doseage or without probenicd.

4. Also you said some azithromycin reistance exists but i thought it was universal in NA, please correct me if im wrong. Does reistance with this particular antibotic mean it would most certainley not affect it?

I appreciate your responses. Ive done alot of reading and its tough to push down anxiety with reading some of this ive mentioned without being knowledgable so im just trying to understand fully what i can.

H. Hunter Handsfield, MD

1 months ago

These questions and the overall context indicate you have read deeply about these issues, but likely including nonprofessional sources. I am aware of no legitimate scientific syphilis resource that believes there is significant risk of any antibiotic suppressing syphilis to a degree that infection persists but blood tests become negative. For sure avoid sites by and for people affected by or worried over syphilis or other STIs -- like Reddit, for example -- and try to limit your searching to professionally run sites (like academic center, scientific journals, public health agencies, etc -- or professional moderated resources like this one. In addition, your "really had me thinking twice" comment implies you are over-thinking and over-interpreting scientific issues you do not fully understand.

1. That TP DNA can be detected in saliva does not imply that saliva can transmit the infection, even with intimate contact and certainly not with superficial contact of the sort implied here.

2. See my comments above.

3. My reply refers to the total amounts of various antibiotics you received. Also, you must not confuse the amount of drug recommended for treatment versus the smaller amounts that would 100% prevent infection and probably cure it.

4. My azithro resistance comment was generalized to the world at large and too over-simple. Indeed resistance now is nearly universal in North America and Western Europe.

Aall is well. You have no syphilis problem. Trust me on this.

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