Semen Culture and Sensitivity: When You Need the Test, and When You Don’t

A semen culture and sensitivity test grows the bacteria or fungi in your semen and tells you which antibiotics kill them. You need it if you have symptoms — burning urine, painful ejaculation, pelvic pain, blood in semen — or if your report shows pus cells above the cut-off. You do not need it as a reflex add-on to every male infertility assessment.

One thing before anything else. If your worry is a recent exposure or a partner with an STI, this is the wrong test. Chlamydia and gonorrhoea need specific PCR testing. A standard culture misses both and hands you a falsely reassuring result.

I order this test most weeks. I also talk men out of it most weeks. Both are the same job.

Red flags: get seen the same day

Do not wait for a culture if you have any of these.

• Fever with a painful, swollen or red scrotum
• Sudden severe testicular pain
• Inability to pass urine
• Pain with rigors or shaking chills

Acute epididymitis treated late carries a real cost. Around 10% of men are left with persistent azoospermia afterwards, and 30% with oligozoospermia (Schuppe, 2017). Everything else on this page is about the non-urgent situation.

In a nutshell

1. The test has two halves. The culture grows the organism. The sensitivity tells you which antibiotic works on it.
2. Routine testing is contested, not settled. A set of international guidelines does recommend semen culture and PCR testing; the role of routine culture is controversial (Rivero, 2023).
3. Symptoms change everything. Burning urine, painful ejaculation, pelvic pain or blood in semen make this test the right call.
4. Growth is common. In 1,689 infertile men, 21% had a positive semen culture with no symptoms at all (Boeri, 2020).
5. Growth is not proof of harm — but it is not nothing. Bacteriospermia is associated with lower concentration, lower progressive motility and higher DNA fragmentation (Farahani, 2021).
6. Treat infection, not colonisation. Antibiotics should not be used in the absence of symptoms or microbiological infection (Rivero, 2023). Note the “or.”

What a semen culture and sensitivity test actually is

It is two tests sold as one. Most men only ever hear about the first.

The culture half

Your semen goes into a nutrient medium and sits in an incubator, usually 24 to 72 hours. Anything that can grow, grows. The lab then identifies it.

Gram staining and semen culture are still the gold standard for detecting bacteria in semen, though PCR and next-generation sequencing now detect a wider range of pathogens than culture can (Henkel, 2024).

The sensitivity half

Once an organism is isolated, the lab tests it against a panel of antibiotics. The report tells you which drugs killed it and which it shrugged off.

Without the sensitivity half, a positive culture is just a name.

Semen culture, sperm culture, semen C/S — all the same test

Labs write it as semen culture, semen C/S, seminal fluid culture, or sperm culture test. If your form says “culture and sensitivity,” you are getting both halves.

The test at a glance

Everything a lab requisition should tell you, in one place.

Sample	Semen, by masturbation into a sterile container
Method	Aerobic culture + antibiotic sensitivity panel
Abstinence	2 to 5 days
Fasting	Not required
Reporting time	24 to 72 hours
Detects	Bacteria and fungi that grow on culture
Does not detect	Chlamydia, gonorrhoea, Mycoplasma, Ureaplasma — these need PCR

That last row is the one nobody tells you, and it is the reason a “negative” report can still be wrong for your situation.

5 steps: how the semen culture test is done

The handling details below are standard laboratory practice, not findings from the studies cited on this page. Your own lab’s protocol takes precedence.

1. Abstain 2 to 5 days. The same window used for a standard semen analysis, so the accompanying parameters stay interpretable.
2. Pass urine, then wash. Wash your hands and genitals properly and dry them. This step is what keeps skin commensals out of your result (Henkel, 2024).
3. Collect into the sterile pot. By masturbation, directly into the container the lab gives you. No lubricant, no condom, no random jar from the kitchen.
4. Get it to the lab fast. Keep it near body temperature and hand it over quickly.
5. Wait 24 to 72 hours. The sample is incubated in a nutrient medium. If something grows, it is identified and tested against a panel of antibiotics.

How to read your semen culture report

Four phrases cover almost every report I am handed.

A negative report means no significant disease-causing organism grew. A positive report means a specific bacterium or fungus was isolated. That is the plain definition — and then the caveats start.

What the report says	What it means	What I usually do
No growth / sterile (negative)	Nothing cultivable grew	Nothing — but see the caution below
Scanty growth	Very low counts, often below the significance threshold	Correlate with symptoms and pus cells; usually no antibiotic
Significant growth + organism named (positive)	A specific organism above the lab’s threshold	Treat if symptoms or leukocytospermia fit
Sensitivity panel: S / I / R	Sensitive, intermediate, resistant to each drug tested	Choose from the S column, guided by the clinical picture

What the colony count means

Ask for it. Most reports never mention one, and without it “positive” tells you very little.

There is no agreed semen threshold. Several studies use more than 10³ CFU/mL to define bacteriospermia (Henkel, 2024). One sperm bank, noting there is no established reference value for semen at all, borrowed the urinary tract criteria — under 10⁴ CFU/mL possible contamination, 10⁴ to 10⁵ suspected infection, over 10⁵ infection — and set ≥10⁴ as its cut-off for an unqualified sample (Huang, 2021).

The decision rule I actually use

“Positive” is not a diagnosis, so here is what replaces it.

• Growth + symptoms → treat, guided by the sensitivity panel.
• Growth + leukocytospermia above 1 × 10⁶/mL → evaluate properly, and usually treat.
• Growth + no symptoms + no leukocytospermia + a low colony count → observe. Repeat if worried. Do not treat.
• Any recognised sexually transmitted pathogen — chlamydia, gonorrhoea, M. genitalium → treat regardless of symptoms, and treat the partner.

Semen culture vs semen analysis: not the same test

These get confused constantly, including by doctors ordering them.

	Semen analysis	Semen culture and sensitivity
What it measures	Count, motility, morphology, volume, pH, round cells	Which organisms grow, and what kills them
Main purpose	Fertility assessment	Infection assessment
Who needs it	Every man in a fertility work-up	Men with symptoms or leukocytospermia
Turnaround	Same day	24 to 72 hours

A semen analysis is the gold-standard first test in any fertility work-up. If you want to know what each line on that report means, I have gone through it in semen analysis interpretation.

What a semen culture test costs in India

Indicative market pricing, not a clinical finding — ring two local labs and confirm, because it varies widely by city and lab.

Test	Typical price range
Semen culture and sensitivity (aerobic)	₹400 – ₹1,200
Anaerobic culture added	Often ₹300 – ₹800 more
Chlamydia / Ureaplasma / Mycoplasma PCR	Billed separately, usually higher than the culture

Ask specifically whether the lab runs anaerobic culture and PCR. Many smaller labs do neither, which matters because this page is about to tell you to ask for both.

The cheaper question is whether you need the test at all.

7 signs you DO need a semen culture test

When any of these is present, I order it without hesitation.

Sign	Why it matters
Burning or pain passing urine	Classic lower urinary tract symptom — moves this from screening to diagnostic
Pain during or after ejaculation	Points at the prostate or seminal vesicles
Pelvic, perineal or scrotal ache	Especially alongside urinary symptoms
Blood in the semen	Usually benign, but it earns a proper work-up
Frankly green or discoloured semen	Not the faint yellowish tinge, which is common and harmless
Suspected prostatitis, epididymitis, orchitis or seminal vesiculitis	Gland inflammation is a direct indication for culture
Unexplained infertility with an abnormal semen analysis	See the honest caveat below

Blood in the semen deserves its own work-up, which I have set out in hematospermia explained. For colour changes, I go through the causes in why is my semen green.

The honest weakness of a symptom-led approach

Most male genital tract infections are asymptomatic (Schuppe, 2017). A symptom-gated policy will therefore miss silent infections. I would rather state that than hide it.

The trade-off is deliberate: testing every man finds mostly commensals. But if you have unexplained infertility, a genuinely abnormal semen analysis, or leukocytospermia, the absence of symptoms is not a reason to skip investigation.

Do you need a semen culture before IVF or IUI?

Many units screen before assisted reproduction. The evidence for doing it routinely in men with no symptoms is weak — fertilisation and pregnancy rates after assisted reproduction were not significantly different between men with and without leukocytospermia (Castellini, 2020). If you are symptomatic or leukocytospermic, culture first. If you are neither, ask your unit what the result would change.

If your worry is a sexual exposure

Do not rely on a semen culture. Get specific chlamydia and gonorrhoea testing at an STD clinic — chlamydia and gonorrhea need their own PCR-based tests and their own treatment.

6 reasons it should not be routine

First, in fairness to the other side. A set of international guidelines does recommend semen culture and PCR testing in the infertility work-up. Rivero’s point is not that the test is worthless, but that “the significance of positive results remains unclear” and that the role of routine culture is controversial (Rivero, 2023). What follows is my reading of an unsettled question, not a guideline.

1. Bacteria in semen are near-universal. Semen is fluid from the testis, epididymis, seminal vesicles and prostate, and it exits through the urethra — the same pipe urine uses. Anaerobes are found in almost all ejaculates, about 71% of them potentially pathogenic, which is exactly why Solomon argues culture should cover anaerobes and be done wherever there is any indication of infection (Solomon, 2017).
2. Fertile men grow bacteria too. The semen microbiome is rich and diverse in both fertile and infertile men, and Lactobacillus was associated with better semen parameters (Farahani, 2021). A positive culture alone cannot explain your infertility.
3. Skin contamination is easy. In 3,160 sperm donor samples, 85.57% grew bacteria — overwhelmingly skin flora: Staphylococcus epidermidis 26.95%, haemolytic staphylococci 16.40%, Corynebacterium 13.28% (Huang, 2021).
4. There is no agreed cut-off. The WHO manual specifies no bacterial threshold for semen (Henkel, 2024). The same sample can read “positive” in one lab and “insignificant” in another.
5. Resistance argues for targeting, not blind courses. Antibiotic resistance is worsening in these pathogens, which is why Solomon argues for proper diagnosis before therapy rather than empirical courses (Solomon, 2017). In Chennai I see men who self-medicate with leftover pharmacy strips before they ever reach me — it muddies the culture and breeds resistance. Bring the strip, do not take it.
6. Chronic prostatitis barely moves your semen numbers. Men come to me certain their prostatitis is destroying their count. Chronic prostatitis has no more than a limited influence on ejaculate variables (Schuppe, 2017).

Pus cells in semen: the number that decides it

If one line on your report should drive this decision, it is this one.

The WHO 2010 manual defines leukocytospermia as more than 1 × 10⁶ peroxidase-positive leukocytes per millilitre of semen (Sharma, 2022) — a threshold carried forward, and the one your lab uses.

Is 8-10 pus cells in sperm normal?

No. 8-10 pus cells in sperm is above the usual range, and it is worth acting on. Most Indian labs report pus cells per high-power field rather than per millilitre. Roughly 1 to 4 round cells per HPF corresponds to the WHO cut-off, so a report of 8 to 10 pus cells per HPF sits above it and warrants evaluation for a genital tract infection alongside your symptoms. The per-field count is an approximation — a peroxidase stain reported per millilitre is the test that settles it. I have written the full explanation in pus cells in semen.

Why the white cells matter

Activated leukocytes generate reactive oxygen species, and that oxidative stress correlates with poor sperm quality, higher DNA fragmentation and lower fertility potential (Sharma, 2022). Men with leukocytospermia show significantly lower progressive and total motility than controls (Moubasher, 2018).

There is a pregnancy signal too, not just a parameter one. In that same study, 23 of 25 men with leukocytospermia were followed after antibiotic treatment, and those whose leukocytospermia cleared had significantly higher pregnancy rates than those in whom it persisted (Moubasher, 2018). Small and uncontrolled, but it points away from my instinct.

The link to infection is weaker than you think

Leukocytospermia is found in about 30% of infertile men — and up to 20% of fertile men (Henkel, 2024). The relationship between leukocytospermia and infection is unclear (Sharma, 2022). White cells tell you there is inflammation, not that a bacterium caused it.

A meta-analysis of 28 case-control studies found fertilisation and pregnancy rates after assisted reproduction were not significantly different between men with and without leukocytospermia. Leukocytospermic samples did show slightly lower concentration and progressive motility (SMD −0.14 and −0.18). Those differences disappeared when analysis was restricted to men with no clinical evidence of seminal tract infection, which is why the authors argued the definition of leukocytospermia should be re-assessed in subfertile couples (Castellini, 2020).

That is the strongest evidence on this page for my position. It comes with a caveat: leukocytospermia with clinical evidence of infection is a different animal.

What bacteria a sperm culture test looks for

From 1,689 men presenting with primary infertility, 21% had an asymptomatic positive semen culture (Boeri, 2020). What grew — these five categories account for 89.5% of isolates:

1. Ureaplasma urealyticum — 37.6%, the most frequent single pathogen
2. Enterobacteriaceae (any type) — 24.8%
3. Other pathogens — 20.3%
4. Chlamydia trachomatis — 3.4%
5. Mycoplasma species — 3.4%

Note how those last two were found: by real-time PCR, on a separate platform, not by culture (Boeri, 2020). That is the practical reason a plain culture cannot clear you of an STI.

Common uropathogens including Chlamydia trachomatis, Ureaplasma urealyticum, Neisseria gonorrhoeae, Mycoplasma hominis and Escherichia coli cause epididymitis, epididymo-orchitis or prostatitis (Sharma, 2022). If you have been told there is no sperm in the semen, an old untreated infection belongs on the list of causes.

How common is chlamydia, really?

The reported figures disagree violently, and you should see the spread rather than one number. One meta-analysis of 56 studies puts prevalence in infertile men at 20.6% with an odds ratio for infertility of 2.28, though with extreme between-study heterogeneity and evidence of publication bias (Keikha, 2023). Boeri found it in 3.4% of positive cultures (Boeri, 2020). Farahani found no difference in prevalence between fertile and infertile men and no significant impact on semen parameters (Farahani, 2021).

Take the high figure with caution. Test properly anyway if you have had an exposure.

Do not guess at a growth report

Find out whether your semen culture actually needs treating

A private consultation with Dr Shah tells you what grew, whether it matters, and what to do next.

Book a Consultationor call +91 97907 83856

Does bacteria in semen damage sperm?

I have changed my position on this since I first wrote this page in 2020, and I would rather say so than quietly edit it.

The evidence that it does

Bacteriospermia was associated with lower sperm concentration, lower progressive motility and higher DNA fragmentation in a meta-analysis of 55 studies covering 51,299 subjects (Farahani, 2021).

A separate meta-analysis of 18 studies comparing 5,797 controls with 3,986 men with bacteriospermia found significantly lower concentration, total count, progressive motility, total motility, normal morphology and viability. Only semen volume was unaffected. Its authors concluded bacteriospermia “should be taken in mind even when asymptomatic” (Pergialiotis, 2018). That is a stronger position than mine.

So the flat claim that no organism is ever associated with worse sperm parameters is no longer defensible. That is what this page used to say. It was wrong.

Three of my own sources disagree with me

It would be dishonest to bury them.

• Boeri concludes his findings show “the importance of an accurate investigation of semen infection” in the routine work-up of infertile men (Boeri, 2020). I read the same data as one in five men growing something harmlessly; he reads it as a reason to look.
• Pergialiotis says bacteriospermia matters even when asymptomatic (Pergialiotis, 2018).
• Henkel goes furthest: bacterial infections, including “silent” ones, are treatable, and antibiotics are the treatment of choice, with anti-inflammatories or antioxidants as adjuncts where oxidative stress is high (Henkel, 2024).

My disagreement with Henkel is about what counts as an infection. It is not about whether infection should be treated.

Three studies say treat the asymptomatic men. Here they are.

Ahmadi’s group ran this three times and got the same answer: asymptomatic Mycoplasma hominis, Mycoplasma genitalium and Chlamydia trachomatis were commoner in infertile men, and semen parameters improved after antibiotics.

They also reported pregnancies. Partners conceived within four months in 58.3%, 43.8% and 42.9% of treated men respectively (Ahmadi, 2017; Ahmadi, 2018a; Ahmadi, 2018b). Uncontrolled, single-group follow-ups with no randomised comparison — but they are pregnancy data, and the claim that conception data are simply lacking is not the whole story.

Note what those men had: PCR-identified Mycoplasma and Chlamydia. Not incidental growth on a routine aerobic culture.

The same distinction applies to prostatitis. Vicari’s 110 patients had diagnosed chronic bacterial prostatitis with an entry requirement of a semen culture of at least 10⁵ CFU/mL — a high-count, clinically defined infection. Those who cleared the organism on levofloxacin showed increased progressive motility and reduced seminal leukocytes and reactive oxygen species (Vicari, 2016).

Where I land

Association is not causation, and a semen parameter is not a pregnancy. But “bacteria never matter” was too strong. The defensible position is narrower: treat infection, not colonisation.

What I will not do is put a man on two months of antibiotics because a routine culture grew a skin commensal. A drug that cannot help you can still cost you a resistant organism and a wrecked gut — and it is one route to low sperm motility you did not start with.

Dr Shahs notes (from my clinical observation)

Reviewing the prescription is usually the most useful thing I do. The commonest consultation here is a man referred for infertility, cultured routinely, grew Staphylococcus, and on doxycycline ever since. No symptoms, ever. Nobody has revisited whether the indication still exists.

To be explicit: do not stop an antibiotic your own doctor prescribed on the strength of a web page. Take the report and the prescription to a doctor and have the indication reviewed. Stopping part-way through a genuine infection is worse than either finishing it or never starting — and partial courses breed exactly the resistance I complained about above.

Hands beat reports. I have found epididymal thickening in men who arrived with three culture reports and no examination. A scan of a report is not an examination.

And the man the test exists for. Burning urine for months, leukocytospermia confirmed on peroxidase staining above 1 × 10⁶/mL, E. coli on culture. Treated on the sensitivity report, symptoms gone, count up on repeat testing. That is why I never say never.

4 myths worth killing

1. “A positive culture means I am infected.” It may mean colonisation or contamination. Without a colony count, symptoms or raised pus cells, positive is not a diagnosis.
2. “Every infertile man should be cultured.” Contested. The role of routine semen culture is controversial and international guidance is not unanimous (Rivero, 2023).
3. “Antibiotics will improve my sperm count.” Only if there is a real infection to clear. Otherwise you are treating a report.
4. “No growth means nothing is wrong.” A sterile culture rules out one cause among many, and it specifically does not rule out chlamydia, gonorrhoea, mycoplasma or ureaplasma — none of which grow on standard aerobic culture (Boeri, 2020). No growth with ongoing symptoms means you need a different test, not no test.

Frequently asked questions

Does a semen culture test for chlamydia and gonorrhea?

Not reliably. Standard aerobic culture misses them. Chlamydia, Mycoplasma and Ureaplasma are detected on a real-time PCR platform, separately from culture (Boeri, 2020). Ask for those specifically if exposure is your concern.

My report says scanty growth. Do I take the antibiotic?

Usually not. Scanty growth generally sits below the significance threshold, and without symptoms or leukocytospermia above 1 × 10⁶/mL there is nothing to treat. Ask for the colony count and take it, with your symptoms, to a doctor.

Can a sperm infection be cured?

Usually, when a genuine pathogen is identified and treatment follows the sensitivity report. In chronic bacterial prostatitis, antibiotics eradicated the organism in about 71% of men, and those men showed improved progressive motility and lower seminal leukocytes and oxidative stress; in the roughly 29% who did not clear it, parameters got worse (Vicari, 2016). Cure depends on clearing the organism, not on taking the drug.

Is “semen sensitivity” the same thing?

Usually it means the sensitivity half of this test — which antibiotics the organism responds to. Occasionally people use it for semen allergy, a separate condition where a partner reacts to seminal fluid. If you meant the second, this is the wrong page.

Can bacteria in semen cause infertility?

Sometimes. Bacteriospermia is associated with lower concentration, lower progressive motility and higher DNA fragmentation (Farahani, 2021), and one meta-analysis found it affects nearly every semen parameter (Pergialiotis, 2018). But fertile men grow the same organisms, so a positive culture alone does not explain a low sperm count.

Get examined, not cultured

If you have burning urine, painful ejaculation, pelvic pain or blood in the semen, get examined. Do not get cultured blindly.

If your semen analysis is normal and you have no symptoms, you do not need this test — and whoever is selling it to you should be able to say what the result would change.

If you have unexplained infertility and an abnormal semen analysis, do not let the absence of symptoms close the question.

And if you are two months into antibiotics for a culture nobody explained, bring the reports and bring the strip. Most men leave my room with one fewer prescription than they walked in with.

You can book a consultation, or read what a sexologist and andrologist assesses at a first visit.

References

1. Rivero MJ, et al. Evaluation and management of male genital tract infections in the setting of male infertility: an updated review. Current Opinion in Urology. 2023. PMID 36861760
2. Boeri L, et al. Semen infections in men with primary infertility in the real-life setting. Fertility and Sterility. 2020. PMID 32299615
3. Farahani L, et al. The semen microbiome and its impact on sperm function and male fertility: a systematic review and meta-analysis. Andrology. 2021. PMID 32794312
4. Henkel R. Leukocytospermia and/or bacteriospermia: impact on male infertility. Journal of Clinical Medicine. 2024. PMID 38792382
5. Solomon M, et al. Semen culture and the assessment of genitourinary tract infections. Indian Journal of Urology. 2017. PMID 28717267
6. Sharma R, et al. Relevance of leukocytospermia and semen culture and its true place in diagnosing and treating male infertility. The World Journal of Men’s Health. 2022. PMID 34169683
7. Castellini C, et al. Relationship between leukocytospermia, reproductive potential after assisted reproductive technology, and sperm parameters: a systematic review and meta-analysis. Andrology. 2020. PMID 31250986
8. Pergialiotis V, et al. The impact of bacteriospermia on semen parameters: a meta-analysis. Journal of Family & Reproductive Health. 2018. PMID 30820210
9. Schuppe HC, et al. Urogenital infection as a risk factor for male infertility. Deutsches Ärzteblatt International. 2017. PMID 28597829
10. Keikha M, et al. Association between Chlamydia trachomatis infection and male infertility: a systematic review and meta-analysis. Mini Reviews in Medicinal Chemistry. 2023. PMID 36043714
11. Moubasher A, et al. Impact of leukocytospermia on sperm dynamic motility parameters, DNA and chromosomal integrity. Central European Journal of Urology. 2018. PMID 30680244
12. Huang C, et al. Bacteriological analysis of semen samples from sperm donors. National Journal of Andrology. 2021. PMID 34914242
13. Ahmadi MH, et al. Asymptomatic infection with Mycoplasma hominis negatively affects semen parameters and leads to male infertility as confirmed by improved semen parameters after antibiotic treatment. Urology. 2017. PMID 27871827
14. Ahmadi MH, et al. Improvement of semen parameters after antibiotic therapy in asymptomatic infertile men infected with Mycoplasma genitalium. Infection. 2018a. PMID 29124647
15. Ahmadi MH, et al. Association of asymptomatic Chlamydia trachomatis infection with male infertility and the effect of antibiotic therapy in improvement of semen quality in infected infertile men. Andrologia. 2018b. PMID 29292525
16. Vicari E, et al. Effect of levofloxacin treatment on semen hyperviscosity in chronic bacterial prostatitis patients. Andrologia. 2016. PMID 26259725