What are the implications of bacteria in semen (ejaculate)?

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From the Guidelines

Bacteria in ejaculate can be a normal finding, but excessive bacteria may indicate an infection that requires treatment, and prophylactic treatment for chlamydia and gonorrhea should be recommended to individuals who have been vaginally or anally penetrated or orally penetrated with ejaculation. The presence of some bacteria in semen is natural, as the male reproductive tract is not sterile 1. Common bacteria found include Staphylococcus, Streptococcus, and Lactobacillus species. However, excessive bacteria (bacteriospermia) may indicate an infection that requires treatment. According to the Centers for Disease Control and Prevention, current recommendations for prophylactic treatment include 125 mg of ceftriaxone intramuscularly, 2 g of metronidazole once orally, and either 1 g of azithromycin once orally or 100 mg of doxycycline twice daily for 1 week 1. Some key points to consider include:

  • The risk of infection and the need for prophylactic treatment depend on the type of sexual contact and whether ejaculation occurred 1
  • Prophylactic treatment should be recommended to individuals who have been vaginally or anally penetrated or orally penetrated with ejaculation 1
  • Good hygiene practices, including regular washing of the genital area and urinating after sexual activity, can help prevent bacterial infections in the reproductive tract. Infections can affect fertility by reducing sperm quality and quantity, so prompt treatment is important if trying to conceive.

From the Research

Bacteria in Ejaculate

  • Bacteria can be associated with male infertility, and antibacterial substances in ejaculates might impair the growth of bacteria in culture 2
  • A study found that washing ejaculate samples before microbiological culture did not improve the detection of bacteria and led to a reduction in colony counts 2
  • The presence of blood in ejaculate, known as hematospermia, can be caused by various factors, including bladder-prostate or systemic malignant pathology, and requires laboratory and instrumental tests for diagnosis and treatment 3

Treatment of Bacterial Infections

  • Azithromycin and ceftriaxone are effective in treating uncomplicated gonorrhea, with azithromycin being associated with a relatively high frequency of gastrointestinal side effects 4
  • A higher dose of ceftriaxone is now recommended for gonorrhea, and doxycycline is the first-line therapy for chlamydia 5
  • The choice of treatment regimen for gonorrhea does not seem to affect retreatment rates, but expedited partner therapy can reduce the likelihood of retreatment 6

Diagnosis and Detection

  • Patient history, physical examination, laboratory tests, and instrumental exams such as transrectal ultrasound and MRI are important for diagnosing and treating hematospermia 3
  • The detection of bacteria in ejaculate can be affected by the presence of antibacterial substances, and washing the sample may not improve detection 2

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Hematospermia: diagnosis and treatment.

Archivio italiano di urologia, andrologia : organo ufficiale [di] Societa italiana di ecografia urologica e nefrologica, 2006

Research

2021 CDC guidelines on sexually transmitted infections.

The Journal of family practice, 2021

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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