15.23A: Prostatitis - Biology

Prostatitis is an inflammation of the prostate which can be caused by bacteria.

Learning Objectives

  • Define the symptoms, diagnostic tests and treatments used for prostatitis

Key Points

  • Bacteria can cause acute and chronic prostatitis.
  • Acute prostatitis is a serious condition that needs immediate treatment with antibiotics. If treated promptly complications are rare.
  • Chronic prostatitis is a rare disease that is harder to treat and has high recurrence rate. In the case of remission, combinations of antibiotics may be a better therapy than a single antibiotic.

Key Terms

  • bactericidal: An agent that kills bacteria.
  • bacteriostatic: A drug that prevents bacterial growth and reproduction but does not necessarily kill them. When it is removed from the environment the bacteria start growing again.
  • cystitis: An inflammation of the urinary bladder.

Prostatitis is an inflammation of the prostate which can be caused by bacteria. Bacterial infections can cause both acute and chronic prostatitis.

Symptoms and diagnosis

Acute prostatitis is relatively easy to diagnose because it presents the general infection symptoms which may include: fever, chills, groin and lower back pain, issues during urination, and general body aches. The prostate is usually enlarged. Testing of urine samples reveals the presence of bacteria and white blood cells. Blood samples can contain bacteria. White blood cells counts are elevated in the complete blood count.

Chronic prostatitis is a rare condition. It usually causes intermittent urinary tract infections (UTIs) which can lead to cystitis. Sometimes there are no symptoms. The diagnosis is made after culturing urine or prostate liquid. Semen analysis can also be used for diagnosis it. PSA (prostate specific antigen) levels may be elevated.


Common bacteria that cause acute prostatitis include gram negative bacteria such as Escherichia coli, Klebsiella, Proteus, Enterobacter, Pseudomonas, as well as gram positive bacteria such as Staphylococcus aureus. E. coli is the major infectious agent that causes chronic prostatitis.


Acute prostatitis is a serious condition that requires immediate treatment to prevent complications such as sepsis. The antibiotics of choice should be bactericidal (e.g., quinolone) not bacteriostatic (e.g., tetracycline) if the infection is life-threatening. Other commonly used antibiotics are doxycycline and ciprofloxacin. Severe infections may require hospitalization, while milder cases (no sepsis) can be treated with antibiotic administration combined with bed rest at home. The infection is usually cured successfully with antibiotics and the recovery is complete without further complications. Treatment of chronic prostatitis requires courses of antibiotic administration for one to two months or a longer course with low doses. The recurrence of the disease is high. In these cases higher success rates of treatment are achieved when a combination of antibiotics is used. Animal studies have shown that E. coli extract with cranberry can prevent chronic prostatitis. The choice of antibiotic for chronic prostatitis also depends on its ability to penetrate the prostatic capsule. Good penetrators of the barrier are quinolones, doxycycline, macrolides and sulfas (Bactrim). In the case of acute prostatitis, the prostate-blood barrier is damaged by the infection so the penetrating ability of the antibiotic is not as important.

As you age, your prostate can become larger. It’s a normal part of aging for most men.

By the time you reach age 40, your prostate might have gone from the size of a walnut to the size of an apricot. By the time you reach 60, it might be the size of a lemon.

Because it surrounds part of the urethra, the enlarged prostate can squeeze that tube. This causes problems when you try to pee. Typically, you won’t see these problems until you’re 50 or older, but they can start earlier.

You might hear a doctor or nurse call this condition benign prostatic hyperplasia, or BPH for short. It is not cancerous.

What is the prostate gland?

The prostate is an organ in male reproductive anatomy. This small gland sits directly below the bladder and plays a role in producing and fine-tuning semen.

The prostate has various functions. The most important is producing seminal fluid, a fluid that is a component of semen. It also plays a role in hormone production and helps regulate urine flow.

Prostate problems are common, especially in older men. The most common include an inflamed prostate, an enlarged prostate, and prostate cancer.

Symptoms of prostate trouble often appear as difficulty urinating, which might include poor bladder control or weak urine flow.

This article provides an overview of the prostate, including its function and structure, where it is, and what medical conditions can affect it.

The prostate is a small, soft organ. On average, it is roughly the size of a walnut or a ping-pong ball. It weighs around 1 ounce (30 grams) and is usually soft and smooth to the touch.

The prostate sits deep in the pelvis, between the penis and the bladder. It is possible to feel the prostate gland by placing a finger into the rectum and pressing toward the front of the body.

The urethra, a tube that carries urine and semen out of the body, passes through the prostate. Because the prostate surrounds this tube, prostate problems can affect urine flow.

This organ is one part of male sexual, or reproductive, anatomy. The other parts include the penis, scrotum, and testes.

The prostate is not essential for life, but it is important for fertility. The following sections discuss the functions of the prostate.

Helping to produce semen

The primary function of the prostate is to contribute prostatic fluid to semen. According to one article , the prostate contributes between 20–30% of fluid to the total semen volume. The remainder comes from the seminal vesicles (50–65%) and the testicles (5%)

Prostatic fluid contains components that make semen an ideal substance for sperm cells to live in, including enzymes, zinc, and citric acid. One important enzyme is prostate-specific antigen (PSA), which helps make the semen thinner and more fluid.

The fluid in semen helps the sperm travel down the urethra and survive the journey towards an egg, which is essential for reproduction.

Prostatic fluid is slightly acidic, but other components of semen make it alkaline overall. This is to counteract the acidity of the vagina and protect the sperm from damage.

Closing the urethra during ejaculation

During ejaculation, the prostate contracts and squirts prostatic fluid into the urethra. Here, it mixes with sperm cells and fluid from the seminal vesicles to create semen, which the body then expels.

When the prostate contracts during ejaculation, it closes off the opening between the bladder and urethra, pushing semen through at speed. This is why, in normal anatomic situations, it is impossible to urinate and ejaculate simultaneously.

Hormone metabolism

The prostate needs androgens, which are male sex hormones, such as testosterone to function correctly.

The prostate contains an enzyme called 5-alpha-reductase, which converts testosterone into a biologically active form called dihydrotestosterone (DHT).

This hormone is important for normal prostate development and function. In the developing male, it is crucial for the development of secondary sex characteristics, such as facial hair.

A capsule of connective tissue that contains muscle fibers surrounds the prostate. This capsule makes the prostate feel elastic to the touch.

Scientists often categorize the prostate into four zones that surround the urethra like layers of an onion.

The following layers make up the prostate, beginning with the outer capsule and ending inside the prostate:

  • Anterior zone. Made of muscle and fibrous tissues, this zone is also called the anterior fibromuscular zone.
  • Peripheral zone. Mostly situated toward the back of the gland, this is where most of the glandular tissue sits.
  • Central zone. This surrounds the ejaculatory ducts and makes up around 25% of the prostate’s total mass.
  • Transition zone. This is the part of the prostate that surrounds the urethra. It is the only portion of the prostate that continues to grow throughout life.

Prostate conditions often cause problems with urination or bladder control. These may include the following:

  • poor bladder control, including frequent bathroom visits
  • urinary urgency, sometimes with only a small amount of urine
  • difficulty starting the urine stream, or stopping and starting the stream while urinating
  • a weak or thin urine stream

Prostate problems can also cause problems with sexual function, urinary tract infections, bladder stones, or in extreme cases, kidney failure.

If a person is unable to urinate at all, they should seek medical attention immediately.

A person should see their doctor if they notice any of the following symptoms:

  • pain while urinating or after ejaculation
  • pain in the penis, scrotum, or the area between the scrotum and anus
  • blood in the urine
  • severe discomfort in the abdomen
  • a weak urine stream or dribbling at the end of urinating
  • fever, chills, or body aches
  • trouble controlling the bladder, such as stopping or delaying urination
  • unable to empty your bladder completely
  • urine with an unusual odor or color

Several medical problems can affect the prostate, including the following:


Prostatitis is a common swelling or inflammation of the prostate. This is the most common prostate problem in males under 50.

Acute prostatitis is a sudden inflammation of the prostate. This can occur due to a bacterial infection. It appears suddenly and clears up quickly with appropriate antibiotic treatment.

When prostate inflammation lasts for longer than 3 months, it is known as chronic prostatitis, or chronic pelvic pain syndrome. This affects 10–15% of males in the U.S.

Enlarged prostate

An enlarged prostate, also known as benign prostatic hypertrophy (BPH), is the most common prostate problem in males over 50.

Most commonly, the enlargement occurs in the transition zone.

When the prostate enlarges, it presses and pinches the urethra, narrowing the urethra tube. The narrowing of the urethra and a reduced ability to empty the bladder cause many of the problems linked with this condition. As this condition persists, the bladder may become weaker and be unable to empty properly.

An enlarged prostate makes it difficult to urinate and, in rare, serious cases, can prevent urination entirely. This is a condition called urinary retention, which requires urgent medical evaluation.

Prostate cancer

According to the American Cancer Society, prostate cancer is the most common form of cancer in males after skin cancer. It affects around 1 in 9 males during their lifetime.

On average, people receive a prostate cancer diagnosis at age 66.

The American Cancer Society state that people can choose whether to get a prostate cancer screening based on their age and risk factors, but that they should be aware of the potential risks of testing beforehand.

Inhibition of tumor growth and sensitization to chemotherapy by RNA interference targeting interleukin-6 in the androgen-independent human prostate cancer PC3 model

The objective of the present study was to investigate the inhibitory effects of interleukin-6 (IL-6) secretion by androgen-independent human prostate cancer PC3 cells on their growth and chemosensitivity. In this study, we established PC3 in which the expression vector containing short hairpin RNA (shRNA) targeting IL-6 was introduced (PC3/sh-IL6). Changes in the growth and sensitivity to docetaxel in PC3/sh-IL6 were compared with those in PC3 transfected with control vector alone (PC3/Co). Concentration of IL-6 in the culture supernatant from PC3/sh-IL6 was approximately 20% of that from PC3/Co. Both in vitro and in vivo, the growth of PC3/sh-IL-6 was significantly inferior to that of PC3/Co, accompanying downregulation of Bcl-2, Bcl-xL, phosphorylated Akt, p44/42 mitogen-activated protein kinase, and signal transducers and activation of transcription 3 in PC3/sh-IL-6 compared with that in PC3/Co. Despite the higher sensitivity of PC3/sh-IL6 to docetaxel than that of PC3/Co, the secretion of IL-6 by both cell lines was increased after treatment with docetaxel due to the formation of positive autocrine loops between these cell lines and NFκB signaling pathways. Furthermore, combined treatment with the proteasome inhibitor bortezomib, which completely inhibited the docetaxel-induced IL-6 secretion via the inactivation of NFκB signaling, resulted in the marked sensitization of these cell lines to docetaxel both in vitro and in vivo. These findings suggest that suppressed IL-6 secretion using shRNA, either alone or in combination with docetaxel and bortezomib, could be a useful therapeutic strategy against androgen-independent prostate cancer. (Cancer Sci 2011 102: 769–775)

Dietary fatty acid quality affects systemic parameters and promotes prostatitis and pre-neoplastic lesions

Environmental and nutritional factors, including fatty acids (FA), are associated with prostatitis, benign prostate hyperplasia and prostate cancer. We hypothesized that different FA in normolipidic diets (7%) affect prostate physiology, increasing the susceptibility to prostate disorders. Thus, we fed male C57/BL6 mice with normolipidic diets based on linseed oil, soybean oil or lard (varying saturated and unsaturated FA contents and ω-3/ω-6 ratios) for 12 or 32 weeks after weaning and examined structural and functional parameters of the ventral prostate (VP) in the systemic metabolic context. Mongolian gerbils were included because they present a metabolic detour for low water consumption (i.e., oxidize FA to produce metabolic water). A linseed oil-based diet (LO, 67.4% PUFAs, ω-3/ω-6 = 3.70) resulted in a thermogenic profile, while a soybean oil-based diet (SO, 52.7% PUFAs, ω-3/ω-6 = 0.11) increased body growth and adiposity. Mice fed lard (PF, 13.1% PUFA, ω-3/ω-6 = 0.07) depicted a biphasic growth, resulting in decreased adiposity in adulthood. SO and PF resulted in hepatic steatosis and steatohepatitis, respectively. PF and SO increased prostate epithelial volume, and lard resulted in epithelial hyperplasia. Animals in the LO group had smaller prostates with predominant atrophic epithelia and inflammatory loci. Inflammatory cells were frequent in the VP of PF mice (predominantly stromal) and LO mice (predominantly luminal). RNAseq after 12 weeks revealed good predictors of a later-onset inflammation. The transcriptome unveiled ontologies related to ER stress after 32 weeks on PF diets. In conclusion, different FA qualities result in different metabolic phenotypes and differentially impact prostate size, epithelial volume, inflammation and gene expression.

Conflict of interest statement

The authors declare no competing interests.


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Several researches have investigated the role of the urinary microbiota in CP/CPPS ( Table 3 ) [65-67].

Table 3.

Studies investigating the microbiota of CP/CPPS [45]

StudySample size (n)Sample typeAnalysis methodRelevant microbiotaPrimary finding
Nickel et al. (2015) [65]110 CP/CPPS, 115 controlsFirst-void urine (VB1), MSU (VB2), postprostatic massage urine (VB3)T-5000 Universal Biosensor Mass SpectrometryBurkholderia, Propionibacterium, StaphylococcusBacterial composition differed significantly between participants with CP/CPPS and controls in initial stream urine (VB1).
No significant differences were observed in midstream (VB2) or postprostatic massage urine (VB3).
Mandar et al. (2017) [66]21 CP/CPPS, 46 controlsSemen16S rRNA gene sequencing (V6 region)Lactobacillus, Gillisia, Prevotella, Corynebacterium, GardnerellaThe semen of CP/CPPS patients have higher species diversity and lower relative abundance of Lactobacillus compared to healthy men.
Shoskes et al. (2016) [67]25 CP/CPPS, 25 controlsMSU16S rRNA gene sequencing (V3 and V4 regions)Bacteroides, Blautia, Faecalibacterium, Ruminococcus, CoprococcusUrinary microbiomes from patients with CP/CPPS have significantly higher phylogenetic alpha diversity compared to controls.
Several clinical measures of severity and clinical phenotype were also associated with the difference.

CP/CPPS, chronic prostatitis/chronic pelvic pain syndrome MSU, midstream urine.

Nickel et al. examined first-void (VB1), midstream void (VB2), and postprostatic massage void (VB3) urines from 110 CP/CPPS patients and 115 controls [68] in the multidisciplinary [65]. Overall species and genus composition differed significantly for first-void urine only (VB1). The bacterial species Burkholderia cenocepacia was confirmed to be overexpressed in the CP/CPPS population [65]. They did not find any putative organisms for CP/CPPS, but the specific microbiome differences observed for B. cenocepacia may indicate a change in overall species balance. Other researchers described B. cenocepacia as a pathogen, presuming that it was involved in the pathogenesis of CP/CPPS [69-71].

Shoskes et al. [67] compared 25 patients with CP/CPPS and 25 controls using 16S rRNA gene sequencing. In the CP/CPPS patients, the phylogenetic diversity was confirmed by the overexpression of 17 bacterial taxa, and they also had more Clostridia and Bacterodia bacterial species. It is unclear why the phylogenetic diversity of the urine microbiota is greater in CP/CPPS patients who are more frequently used antibiotics. Patients have a high prevalence of anaerobic bacteria, which indicates pathogens that are not usually cultured or treated in clinical practice

Shoskes et al. [72] recently investigated the role of intestinal microbiomes in CP/CPPS. It is believed that intestinal microbiomes can affect the symptoms or clinical phenotype of CP/CPPS patients. In this study, Prevotella was found to be dominant in the intestines of the control group, which can be assumed to optimize energy intake and prevent inflammation. Therefore, having less Prevotella in the CP/CPPS patient’s intestine could be considered as one of the etiologies. The well-balanced microbiota is in a state of 𠇎ubiosis” that functions smoothly for the whole organism. Meanwhile, qualitative and quantitative changes of microbiota are called 𠇍ysbiosis.” Thus, treatment approaches could aim to restore the microbiota by removing bacteria and growth and inflammation-causing toxins produced by the microorganism [73].

Mandar et al. [66] studied the semen of 21 men with CP/CPPS and 46 controls using 16S rRNA gene sequencing. They showed that the difference between these 2 groups is relative depletion in the genus Lactobacillus. In patients with prostatitis, the relative abundance of the species Lactobacillus iners was significantly lower. In addition, they noted greater microbial diversity in patients with prostatitis.

Murphy et al. [74,75] isolated certain Staphylococcus epidermal strains from expressed prostate secretions from healthy human males and performed intraurethral instillation using murine experimental prostatitis. They reported that the instillation reduced the pelvic tactile allodynia responses and the increased T-cell numbers associated with prostatitis. Their results showed new possibilities for commensal Staphylococcus epidermis and its cellular components in the treatment of prostatitis-related pain.

Because the pathophysiology of CP/CPPS is not well understood, the research of the urogenital microbiota could be used not only to understand the pathology of the disease but also to explore treatments that can restore eubiosis and prevent the vicious cycle of dysbiosis-urogenital infections.

Prostatitis/Chronic Pelvic Pain Syndrome

We review the diagnosis, categorization, and treatment of prostatitis/chronic pelvic pain syndrome based on the National Institutes of Health (NIH) classification. Prostatitis is an extremely common syndrome that afflicts 2%–10% of men. Formerly a purely clinical diagnosis, prostatitis is now classified within a complex series of syndromes (NIH category I–IV prostatitis) that vary widely in clinical presentation and response to treatment. Acute bacterial prostatitis (category I) and chronic bacterial prostatitis (category II) are characterized by uropathogenic infections of the prostate gland that respond well to antimicrobial treatment. In contrast, chronic prostatitis/chronic pelvic pain syndrome (category III), which accounts for 90%–95% of prostatitis cases, is of unknown etiology and is marked by a mixture of pain, urinary, and ejaculatory symptoms with no uniformly effective therapy. Asymptomatic inflammatory prostatitis (category IV) is an incidental finding of unknown clinical significance. This review describes the current status of prostatitis syndromes and explores the future prospects of new diagnostic tools and therapies.

This article has been retracted: please see Elsevier Policy on Article Withdrawal (

This article has been retracted at the request of the authors. They believe that the article contains findings that may be unreliable. As the authors re-reviewed the data points presented in the article, they identified differences between some of the plate reader values and those that were reported in the article. For some of the duplicates run, one of the values was indeed from the plate reader data, whereas the source of the counterpart value is not easily apparent. Therefore, because the authors could not replicate some of the counterpoint values, they cannot state if the data points represent the actual data generated in the experiments described. Furthermore, the duplicate values may not have been handled in the manner described within the Materials and Methods section of the paper and the values were not blanked. Taken together, the inconsistencies in validating the data collection and recordation warrant retraction of the article. The authors sincerely apologize for any inconvenience this might cause.

None of the other authors declare a conflict of interest.

This study was supported by a grant from the National Institutes of Health, National Cancer Institute (CA65463) and a research grant from Onconome Incorporated.

R. Getzenberg holds a patent for the technology described in this study. This patent is owned by the University of Pittsburgh and Johns Hopkins University and has been licensed to Onconome Inc. He has also received a research grant from Onconome Inc. and is a consultant to the company. The terms of this arrangement are managed by the Johns Hopkins University in accordance with its conflict of interest policies.

Chronic Prostatitis Patients Require Psychological Therapy

With the increase of the age, many males are more vulnerable to prostatitis, while massive sufferers will encounter fear and anxiety which will affect their work and life.

As time goes by, the severe psychological problem will invite a vicious circle, and even affect the progress of therapy. What you need to known is that attaching importance to psychological relaxation and positive attitude towards disease are also very important for therapy.

Causes of psychological disorders in chronic prostatitis

Fear is the biggest cause of anxiety and tension in sufferers with chronic prostatitis, sufferers are full of fear when it comes to chronic prostatitis due to a lack of correct knowledge of chronic prostatitis, it will cause sexual dysfunction, prostate cancer, renal failure, infertility, and sexually transmitted diseases.

2. Negative information about chronic prostatitis

Adverse and unethical advertisement always exaggerates the damage of chronic prostatitis and how difficult it is to be cured. And mistakenly connect all the other male diseases with chronic prostatitis to achieve some commercial purposes and cheating on the sufferers.

3. Well-constructed resources

There is a lack of correct communication channels for sufferers. For instance, at present, many media release some incorrect knowledge in the form of columns, lectures or advertisements without strict censorship, resulting in an illusion that there are many famous experts who specialize in male diseases. When sufferers need to learn about some information related to chronic prostatitis, it is hard for them to judge if the source can be reliable.

Psychological problems occur when patients are not properly guided. Since patients lack correct knowledge, they will often mistake some normal physiological reactions as abnormal pathological signs, long-term excessive worry will cause fixed symptoms. Besides, Focus on one or more symptoms and amplify your senses so that you can't pull yourself out of the vicious circle.

Therapy of psychological disorders when it comes to chronic rostatitis.

First of all, sufferers should insist on the clinical therapy for a long period. Combined with necessary chemical and physical therapy, antibiotics and anti-inflammatory drugs, such as Diuretic and Anti-inflammatory Pill, which is very helpful to the sufferer's condition.

What&rsquos more, it is needed to develop a good doctor-sufferer relationship. Doctors should listen to sufferers' detailed medical history and catharsis, give them understanding, comfort, guidance, and build trust and friendship.

Health education is likewise needed. Doctors should also Introduce the biology and anatomy of the prostate and the knowledge of chronic prostatitis to the sufferers so that they can understand that chronic prostatitis is merely a common trouble, which has no business with occurrence of prostate cancer, does not directly spark off sexual dysfunction, and it does not belong to sexually transmitted diseases as well.

Additionally, always encourage sufferers to establish a harmonious family and social relations, to accept prostatitis with a positive attitude, and to work and live with symptoms. As a consequence, it can be seen that while sufferers with prostatitis receive drug therapy, it is also extremely important to actively participate in psychological therapy.

Prostate Disease

There are three distinct types of disease of the prostate gland. These diseases share many symptoms, but have different causes. This makes it very important to include prostate cancer screenings as a component of the annual physical examination and to be referred to a urologist if symptoms indicative of possible prostate disease are identified. In addition to the information and resources provided within this website, we encourage you to review the information included in the NIH publication What I Need to Know About Prostate Problems.

Benign Prostatic Hyperplasia (BPH) is a non-cancerous enlargement of the prostate gland that affects approximately 50% of all men before the age of 50 and greater than 75% percent of men over the age of 60. Symptoms include difficulties associated with urinating, an urge to urinate even when the bladder is empty (urgency), frequent urination, especially at night, and a weak or intermittent stream or a feeling of incomplete emptying of the bladder and/or dribbling of urine. Additional information on BPH is accessible through the Benign Prostatic Hyperplasia link.

Prostatitis is an inflammation of the prostate that may be caused by a bacterial infection. This disease may affect men of any age and can occur in any prostate whether small or enlarged. Symptoms of prostatitis are similar to those caused by an enlarged prostate and include urge frequency with difficulty in emptying the bladder. Prostatitis may be indicated by chills, fever and by pain or burning during urination.

Prostate cancer is the second leading cause of cancer deaths among men. However early detection often leads to the effective treatment of prostate cancer. In the majority of cases, prostate cancer will be detected while it is still localized, rather than metastasized (spread). When prostate cancer is detected early and treated, the five-year outcome is generally very successful. The prostate cancer screening process is critical in early detection.

Prostate cancer symptoms include difficulty with beginning urination, a frequent need to urinate , primarily at night the inability to urinate weak or sporadic urine flow painful or a burning sensation during urination painful ejaculation blood in the urine or semen and pain in the back, hips or located in the extremities.

It is recommended that males age 50 and greater be screened annually. Those with a family history of prostate cancer or those identified as African American, should begin annual screenings at age 40, as research data indicates race and genetics are factors in the development of this cancer.