Non-Bacterial Prostatitis (CP/CPPS)
Chronic prostatitis · Non-bacterial prostatitis · CP/CPPS · NIH type III
Non-bacterial prostatitis (CP/CPPS): why the cultures come back negative, what we actually find, and how it is treated
Nine out of ten men with chronic prostatic symptoms are told their prostatitis is “non-bacterial” or “chronic pelvic pain syndrome”, that no infection is present, and that the aim is to manage the pain. In more than three decades of treating chronic prostatitis we have yet to see a case that remained non-microbial once it was investigated properly. “Non-bacterial” is a diagnosis of what was not found. This page explains why the label exists, why standard cultures are negative, what our own records show when the gland is opened and the laboratory looks, and how we treat it.
Non-bacterial prostatitis at a glance
What “CP/CPPS” means, and how a man ends up with the label
The classification in use worldwide comes from a 1999 US National Institutes of Health consensus [1]. It has four categories. Type I is acute bacterial prostatitis: fever, a tender gland, a positive culture. Type II is chronic bacterial prostatitis: the same organism recovered repeatedly from prostatic fluid or urine. Type IV is inflammation found by chance in a man with no symptoms.
Type III, chronic prostatitis / chronic pelvic pain syndrome or CP/CPPS, is everything else: pelvic, perineal or genital pain for at least three of the previous six months, with or without urinary and sexual symptoms, and a standard culture that is negative. It is subdivided into IIIa (white cells in the prostatic fluid or semen, “inflammatory”) and IIIb (“non-inflammatory”). “Non-bacterial prostatitis”, “abacterial prostatitis” and “prostatodynia” are older names for the same category.
Read the definition again. Type III is not defined by what the prostate contains. It is defined by what a particular test did not detect. That is the whole argument of this page.
What “standard culture” usually means
A mid-stream urine sample, sometimes a semen sample, and in the more careful clinics the Meares–Stamey four-glass test or its two-glass shortcut [7,8]: urine before and after a brief prostatic massage, cultured for the common urinary pathogens over two to three days.
The test was designed in 1968 to distinguish a prostatic infection from a urethral or bladder one. It was never designed to recover organisms sealed inside obstructed ducts, growing in biofilm, in a gland that has been fibrotic for years. Used for that purpose it fails predictably, and the failure is recorded as “no infection”.
How common is non-bacterial prostatitis?
Very: roughly 90% of men with chronic prostatitis symptoms are placed in type III, which makes “non-bacterial” the commonest prostatitis diagnosis in the world. Chronic prostatitis itself affects something like one man in ten at some point in life, so a large share of the men reading this page have the label. The number says nothing about how many of those glands are actually free of organisms. In the men who reach us with the diagnosis, in our experience, that fraction is close to zero once the gland is sampled properly, which is the subject of the next two sections.
In our opinion “non-bacterial prostatitis” is, in the great majority of cases, chronic bacterial prostatitis that the standard method could not demonstrate. This is a minority position among urologists, and the guidelines say otherwise; we hold it because of what we find, examination after examination, when the prostate is pressed, sampled and cultured properly, and because of what happens to the symptoms when those organisms are cleared.
Why the cultures are negative: you cannot culture what has not been released
A negative culture in an established chronic prostatitis is the expected result of the standard method, for four reasons. None of them is that the organisms are absent.
1. The sample comes from the open ducts
Chronic inflammation blocks glandular ducts and seals secretion, pus and organisms behind them. Urine and semen, and the fluid released by a gentle massage, come from the ducts that still drain, the healthiest part of the gland. The infection lives in the ducts that do not. A sample taken without first opening those ducts under targeted, firm pressure is a sample of the wrong compartment.
2. Biofilm does not shed on request
Organisms in a chronically infected prostate live attached to duct walls, debris and calcifications, in biofilm [5,12]. Biofilm bacteria shed into fluid intermittently and in small numbers, well below what a two-day plate will grow. This is why the same man can have five negative cultures and then, after the right pressure on the right region, grow an organism resistant to most of the antibiotics he has ever taken.
3. The laboratory stops too early and looks too narrowly
Routine urine culture is set up for the usual urinary pathogens and read at 48 hours. Many of the organisms we recover (enterococci, coagulase-negative staphylococci, Ureaplasma and Mycoplasma, slow growers and anaerobes) need semen and expressed prostatic secretion cultured on the right media for six to seven days, with PCR where indicated, and a microbiologist who does not dismiss a staphylococcus as skin contamination before asking whether it explains the patient’s ultrasound. Culture-independent sequencing has repeatedly found bacterial DNA in the prostatic fluid and urine of men labelled CP/CPPS [2,3,4,6]: the organisms are there; they are not being grown.
4. The patient has just taken antibiotics
Most men reaching a specialist have had several courses. Sampling within three weeks of an antibiotic, or without a few days of abstinence, suppresses growth without curing anything. A negative culture obtained that way is uninterpretable, and it is very often the one on which the “non-bacterial” label was based.
Organisms enter through the urethra and colonise the periurethral ducts first, then spread outward over years. Cultures release what is nearest the surface. So the first organism found is usually the most recent one, and the original, most resistant infection stays hidden in the periurethral zone until the ducts around it are opened. In our records a new organism, one that was not present in the first positive culture, appears in three out of four men with repeated cultures. These are not new infections. They are older ones reached for the first time.
What our records show: when the prostate is opened and the laboratory looks, the cultures are positive
In 2026 we audited the microbiology in our own archive: 1,306 laboratory reports on expressed prostatic secretion, semen and urethral samples from 568 men treated between 2020 and 2026, cultures and, where the laboratory runs them, molecular tests for Chlamydia, Ureaplasma and Mycoplasma. Most of these men had arrived with a diagnosis of “non-bacterial” or “chronic pelvic pain” prostatitis from elsewhere.
Of the 13 men whose first report was negative, six of them from outside laboratories, every one was positive on a later sample. Among the men with repeated reports, one in five grew five or more different organisms over the course of treatment, and in three out of four an organism turned up that was absent from the first positive report: the sequential release described above, seen in the archive rather than assumed. A single positive culture is, in a chronic gland, almost never the whole story.
The organisms
The list is led by Enterococcus faecalis (39% of men), Escherichia coli, Staphylococcus haemolyticus, Staphylococcus aureus and Staphylococcus hominis (each in roughly one man in four), followed by Klebsiella pneumoniae and Chlamydia (each in about one in seven), Staphylococcus warneri, Ureaplasma and Proteus mirabilis (about one in eleven), then Staphylococcus lugdunensis, Enterobacter cloacae, Staphylococcus epidermidis, Mycoplasma, Pseudomonas aeruginosa and Morganella morganii. Three of the top five are staphylococci that a routine laboratory report will often label “skin flora” and discard. In a man whose prostate is hard, enlarged and full of blocked ducts on ultrasound, and whose symptoms resolve when that organism is cleared, we do not discard it.
Chlamydia, Ureaplasma and Mycoplasma deserve a separate word: they do not grow on routine culture plates at all. Our laboratory identifies them by PCR and immunofluorescence on the same prostatic-fluid and semen samples, and together they were found in roughly one man in four. A standard urine culture never reports them, which is one more reason the “non-bacterial” label is handed out so freely.
How to read these numbers
They describe the men who reached this clinic, a population selected for long, treatment-resistant disease, and the reports that were filed in their records. They are not a prevalence estimate for all men with pelvic pain; an archive over-represents positive reports, because those are the ones that get filed; and a positive culture on its own does not prove that the organism causes the symptoms. The ultrasound, the leukocyte count and the response to treatment do that, case by case. The full audit is being prepared for peer-reviewed publication. The prostate-volume results are on the protocol page.
What the ultrasound shows: the inflammation is visible even when the culture is not
A man labelled CP/CPPS has, by definition, a negative culture. He very rarely has a normal transrectal ultrasound. What we see, examination after examination, is the anatomy of a chronic infection: an enlarged gland with hard, hypoechoic regions where inflamed tissue has been replaced by fibrosis; dilated, obstructed ducts; calcifications, which are calcium salts deposited into tissue that was already inflamed and are a marker of how long the disease has been present [13]; and, on Doppler, the increased blood flow of active inflammation next to the poorly perfused hard zones.
None of that needs a culture to be seen. It is why, for us, a negative culture at the start is the beginning of the investigation and never the end of it, and why the prostatic pressure that opens the ducts is the first step of treatment and the first step of diagnosis at the same time. Every region the ultrasound marks as diseased is pressed, sampled and cultured; every new organism changes the antibiotic; the ultrasound is repeated so that the trend is visible week by week. The full work-up is described on how we diagnose chronic prostatitis.
Is non-bacterial prostatitis dangerous? What years of “management” do
CP/CPPS is not cancer and it does not shorten life, which is the reassurance most men are given. But a gland that stays infected and inflamed for years does not stand still, and in our experience the cost of treating the label instead of the disease is paid in four places.
The gland itself
Fibrosis spreads, more ducts block, calcifications multiply and the prostate slowly enlarges. In our experience this is how a large share of what is later called “benign prostatic hyperplasia” begins; our records on this are on the enlarged prostate page.
Erections and ejaculation
The nerves and vessels of erection run through and beside the gland. A fibrotic, congested prostate compresses them; erectile dysfunction, premature ejaculation, pain on ejaculation and loss of libido follow, and are then treated as “psychological”. See the section below.
Fertility and semen
Infected prostatic fluid and seminal vesicles damage sperm motility and morphology, and blood in the semen (hematospermia) is common. Male infertility is, in our experience, very often a prostatitis that nobody looked for.
The man
Years of pain and frequency, broken sleep, lost confidence and the exhaustion of being told it is in his head. The men who reach us have, on average, been ill for years and have been through several urologists and several countries. The duration makes the treatment longer, not the disease incurable.
Non-bacterial prostatitis treatment: the conventional pathway, and how we treat it
What “managing” CP/CPPS looks like
Because type III is defined as non-infectious, guideline treatment is symptomatic: alpha-blockers, anti-inflammatories, pelvic-floor physiotherapy, neuropathic pain drugs, sometimes phytotherapy or acupuncture, usually assembled into a personalised combination according to the patient’s symptom “phenotype” [11]. Antibiotics are offered once, empirically, and withdrawn if the man does not improve within a few weeks, a decision taken without ever having opened the gland.
The evidence for this pathway is honest about its limits. Network meta-analyses and Cochrane reviews find modest, short-term improvements in symptom scores for several of these treatments and no cure for any of them [9,10]. Men are told, in good faith, that CP/CPPS is a chronic condition to be lived with.
How we treat it
The men who come to us have been through that pathway, often in more than one country. They arrive with a folder of negative cultures, a prostate that has never been properly pressed, and a diagnosis that was made by exclusion. We treat them for the disease the ultrasound shows, with the same protocol we use for every chronic prostatitis, the Georgiadis Protocol (GCPP): targeted prostatic pressure that opens the blocked ducts, full cultures of what is released, antibiotics chosen from those cultures and delivered where the organisms are (including intraprostatic injections where needed), repeated ultrasound and microbiology until the cultures are negative and stay negative, the white cells are down and the gland has settled. How the protocol works, week by week.
We do not accept “non-bacterial” as a diagnosis. We examine the gland by transrectal ultrasound with Doppler, we apply targeted prostatic pressure to the diseased regions before the sample is taken, we culture expressed prostatic secretion and semen fully (six to seven days, the right media, PCR where indicated) through a microbiology laboratory that specialises in the urogenital tract, and we repeat the cultures throughout treatment because opening a new region routinely releases an organism nobody had seen. Then we treat the organisms where they are. The symptoms are the same in “bacterial” and “non-bacterial” prostatitis because the disease is the same: pelvic, perineal, testicular or penile pain, pain after ejaculation, frequency, urgency, a weak stream, burning, erectile and ejaculatory problems. When the culture is finally positive, nothing about the patient has changed except the label. Symptoms of chronic prostatitis.
CPPS and erectile dysfunction: the erection problem is usually the prostate problem
Erectile dysfunction is one of the commonest reasons a man labelled CP/CPPS looks for a second opinion, and it is routinely treated as a separate, psychological consequence of chronic pain. In our experience it is a direct mechanical consequence of the inflamed gland. The nerves and vessels that supply erection run through and alongside the prostate; fibrotic, inflamed tissue compresses them, and a chronically congested gland disturbs the pelvic circulation on which a rigid erection depends. Premature ejaculation and loss of libido belong to the same mechanism.
When the gland is opened and the inflammation cleared, erectile function is very often one of the first things to recover. Where it does not, it is usually because the erectile tissue itself has been under-perfused for so long that it has developed fibrosis of its own, which needs its own treatment on top of curing the prostatitis and cannot be predicted before treatment starts. More on chronic prostatitis and sexual dysfunction.
Told your prostatitis is “non-bacterial”?
Send us your history, every culture report you have (positive or negative, with dates), your ultrasound or MRI reports and the antibiotics you have taken. We will tell you honestly whether what we see fits a chronic infection, and what a first visit would involve.
Questions patients ask about non-bacterial prostatitis
Is non-bacterial prostatitis real?
As a category of test results, yes: a great many men have chronic prostatic symptoms and negative standard cultures. As a disease without organisms, we have never seen it. Every case we have investigated with targeted pressure, proper culture and repeated sampling has eventually grown organisms, and has behaved like an infection when treated as one. The label describes the limits of the method, not the contents of the gland.
Why were all my cultures negative?
Most likely because the sample came from the open ducts of the gland rather than the blocked ones where the infection lives, because no firm targeted pressure was applied before sampling, because the laboratory read the plates at 48 hours and looked only for the usual urinary pathogens, or because you had recently taken antibiotics. Often all four. See also How come you find microbes that others don’t?
Can non-bacterial prostatitis be cured?
We treat it as chronic prostatitis, because in our experience that is what it is, and chronic prostatitis in our records is a treatable disease: on the protocol page you can see the audited prostate-volume results of 624 patients, documented cases and the microbiology of the organisms cleared. The men who complete the protocol, roughly eight in ten of those who start, are the men we see cured. What cannot be promised in advance is how many treatment stages a particular gland will need, because that depends on how long it has been infected and how many organisms it holds.
Is non-bacterial prostatitis dangerous?
It is not cancer and it does not threaten life. Left as a “managed” condition for years, though, the infected gland fibroses, calcifies and enlarges, erections and ejaculation suffer, semen quality falls and the symptoms become entrenched. The danger is in the years lost, not in the diagnosis.
My urologist says the staphylococcus in my semen is contamination. Is it?
Coagulase-negative staphylococci live on the skin, so a laboratory is right to ask the question. But Staphylococcus haemolyticus and S. hominis are among the five organisms we recover most often from prostatic secretion after pressure, they are frequently multi-resistant, and clearing them is followed by a measurable fall in prostate volume and resolution of symptoms. An organism that behaves like that is not a contaminant. The ultrasound, the leukocyte count and the response to treatment decide, not the name of the species.
Does chronic pelvic pain syndrome cause erectile dysfunction?
Yes, and mechanically rather than psychologically: the inflamed, fibrotic gland compresses the nerves and vessels that supply erection. Erectile function is often among the first things to improve once the gland is opened. Where fibrosis of the erectile tissue itself has developed after years of poor perfusion, it needs treatment of its own.
Does diet help non-bacterial prostatitis?
Diet does not clear an infection, and no food will open a blocked duct. Avoiding alcohol, caffeine and very spicy food reduces irritation of the bladder and urethra while the gland is inflamed, and a sensible diet supports recovery, but it is a comfort measure, not a treatment. Our notes on foods and the prostate.
I have had CPPS for ten years. Is it too late?
No. A gland that has been inflamed for a decade has more fibrosis, more calcification and more organisms to clear, so it needs more treatment, but it is the same disease and it responds to the same protocol. Patients who have had symptoms for many years are the majority of the men we treat, and calcifications are not a barrier: they are a marker of duration, not of incurability.
What should I bring to a first consultation?
Every culture report you have, positive or negative, with dates; every ultrasound or MRI report; a list of the antibiotics you have taken and when; and at least three weeks without antibiotics and three to four days without ejaculation before the first sample. The first visit includes a transrectal ultrasound with Doppler, targeted prostatic pressure and the first cultures of expressed secretion and semen.
Sources
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- Nickel JC, Stephens A, Landis JR, et al. Search for microorganisms in men with urologic chronic pelvic pain syndrome: a culture-independent analysis in the MAPP Research Network. J Urol. 2015;194(1):127–135.
- Krieger JN, Riley DE. Bacteria in the chronic prostatitis–chronic pelvic pain syndrome: molecular approaches to critical research questions. J Urol. 2002;167(6):2574–2583.
- Krieger JN, Riley DE, Roberts MC, Berger RE. Prokaryotic DNA sequences in patients with chronic idiopathic prostatitis. J Clin Microbiol. 1996;34(12):3120–3128.
- Nickel JC, Costerton JW. Bacterial localization in antibiotic-refractory chronic bacterial prostatitis. Prostate. 1993;23(2):107–114.
- Shoskes DA, Altemus J, Polackwich AS, Tucky B, Wang H, Eng C. The urinary microbiome differs significantly between patients with chronic prostatitis/chronic pelvic pain syndrome and controls as well as between patients with different clinical phenotypes. Urology. 2016;92:26–32.
- Meares EM, Stamey TA. Bacteriologic localization patterns in bacterial prostatitis and urethritis. Invest Urol. 1968;5(5):492–518.
- Nickel JC, Shoskes D, Wang Y, et al. How does the pre-massage and post-massage 2-glass test compare to the Meares–Stamey 4-glass test in men with chronic prostatitis/chronic pelvic pain syndrome? J Urol. 2006;176(1):119–124.
- Anothaisintawee T, Attia J, Nickel JC, et al. Management of chronic prostatitis/chronic pelvic pain syndrome: a systematic review and network meta-analysis. JAMA. 2011;305(1):78–86.
- Franco JVA, Turk T, Jung JH, et al. Pharmacological interventions for treating chronic prostatitis/chronic pelvic pain syndrome: a Cochrane systematic review. BJU Int. 2020;125(4):490–496.
- Shoskes DA, Nickel JC, Kattan MW. Phenotypically directed multimodal therapy for chronic prostatitis/chronic pelvic pain syndrome: a prospective study using UPOINT. Urology. 2010;75(6):1249–1253.
- Mazzoli S. Biofilms in chronic bacterial prostatitis (NIH-II) and in prostatic calcifications. FEMS Immunol Med Microbiol. 2010;59(3):337–344.
- Geramoutsos I, Gyftopoulos K, Perimenis P, et al. Clinical correlation of prostatic lithiasis with chronic pelvic pain syndromes in young adults. Eur Urol. 2004;45(3):333–338.
- Magri V, Wagenlehner FM, Montanari E, et al. Semen analysis in chronic bacterial prostatitis: diagnostic and therapeutic implications. Asian J Androl. 2009;11(4):461–477.
- European Association of Urology. EAU Guidelines on Chronic Pelvic Pain and on Urological Infections, 2026 edition. Arnhem: EAU Guidelines Office.
This page describes the clinical position and experience of Georgiadis Urology and is provided for information; it is not a substitute for individual medical advice. The classification of prostatitis and the guideline management of CP/CPPS are summarised from the sources cited. Our position that a microbial cause can be demonstrated in the great majority of these patients is our clinical experience, supported by our own records, and differs from current guidelines. Individual results vary and no outcome can be guaranteed.
