Most doctors fail to address the collateral damage of broad-spectrum antibiotics.
HEALTH When was the last time a physician mentioned probiotics to you after prescribing antibiotics? Many patients are aware that powerful antibiotics kill sickening bacteria. Few understand that beneficial bacteria are sacrificed in the process. Even less realize that nearly 70 percent of the immune system involves the intestinal tract where roughly 500 species of flora reside in a population of about 100 trillion microorganisms.  To maintain a beneficial symbiotic relationship, the "bad" bacteria must not multiply to a point where they significantly outnumber and disrupt effectiveness of the heterotrophic "good," which feeds on the former.
How is "bad bacteria" formed?
Healthy gastrointestinal flora help fight off infection during the putrefaction of wastes, which multiply so-called "bad" bacteria or dysbiosis. A diet high in fat, animal flesh and sodium chloride and low in insoluble fiber "produces an increased concentration of Bacteroides sp. and a decreased concentration of Bifidobacteria sp. in stool."  Excessive sugar, processed foods and even beer can disturb healthy flora. "Good" bacteria have a major role in metabolizing dietary carcinogens. So a diet that lacks a proper variety of fruits, vegetables and fibers or the use of antibiotics can contribute to the proliferation of "bad" bacteria.
Most raw foods, especially those with chlorophyll, feed the friendly intestinal bacteria. Excessive meat consumption has a byproduct of Bacteroides sp. that produces the enzyme urease, which hydrolyzes urea to ammonia, raising stool pH. The risk of colon cancer increases when stool pH is relatively high. Bifidobacteria sp., the "good" bacteria that decreases during putrefaction dysbiosis, ferments soluble fiber, thereby making short-chain fatty acids like butyrate. Butyrate counteracts many of the negative effects caused by harmful bacteria like Bacteroides sp. It lowers stool pH, causes neoplastic cells to differentiate, decreases inflammation in ulcerative colitis, and decreases absorption of ammonia from the intestine. 
Gut flora can also be upset by intestinal cleanses designed to eliminate accumulated wastes and parasites. Some "good" bacteria is lost in the process which may then require probiotics to restore proper balance.
What are the effects of bacteria imbalance?
Commonly, women develop yeast infections following ingestion of antibiotics. It is often misunderstood that the yeast proliferation, Candida albicans can also affect the epithelial cells of men and lead to fungal infections. Broad-spectrum antibiotics may affect the host's health and ability to digest food, ferment carbohydrates and metabolize bile acids. Use of antibiotics, particularly in children, can predispose ones to Inflammatory Bowel Disease (IBD). Probiotics can help treat IBD. 
Signs and symptoms of a male yeast infection include a reddish rash, along with itching or burning at the tip of the penis. Fortunately, most male yeast infections are easily treated with an over-the-counter antifungal treatment, such as Monistat. (Yes, men can use it too.)  However, yeast infection from a sexual partner can travel through the urethra and travel to the prostrate or become systemic.
The more common symptoms of male yeast infection are constipation, malodorous breath, bloating, indigestion, frequent intestinal gas, frequent diarrhea, very loose stools, sexual dysfunction, irratibility and mood swings, fatigue or lack of energy, memory loss, jock itch, dry itchy flaky skin, athletes feet, and prostate problems. One may also develop a craving for sweets, pastas, breads, chips, (carbohydrates) etc. — any of the foods that feed the male yeast infection since the parasite demands to be fed. 
What are probiotics and prebiotics?
"Probiotics" were defined by a group of scientists convened by the Food and Agriculture Organization of the United Nations (New York) as "live microbes which when administered in adequate amounts confer a health benefit on the host." Generally formed from refrigerated dairy products but also available in non-dairy vegan formulations, they make certain B-group vitamins (B2, B12, folic acid and biotin) and vitamin K in the gut. They also regulate the immune system. 
"Prebiotics," which do not need to be live, are non-digestible substances that, when consumed, provide a beneficial physiological effect on the host by selectively stimulating the favorable growth or activity of a limited number of indigenous bacteria.  Common sources of Prebiotics include: asparagus, garlic, leeks, onions, Jerusalem artichokes, berries, bananas, tomatoes, chicory, spinach, kale, chard, mustard greens, lentils, navy beans, garbanzo beans, black beans, whole grains, oats, barley, and wheat. 
How can "good bacteria" be maintained?
To maintain or restore the proper level of good bacteria, people may consume properly labeled yogurt with live cultures, prebiotic or probiotic supplements. Prebiotics stimulate creation of good flora while probiotics should include necessary organisms. It is important to recognize that the acid pH level varies throughout the intestinal tract. Similarly, "good bacteria" present in the stomach differs from that which is active in the small intestine. [1,6]
Yogurts that carry the Live Active Culture seal deliver an adequate quantity of yogurt starter bacteria, but the level of any additional bacteria cannot be presumed. One exception is DanActive®, a fermented milk product by Dannon (The Groupe Danone, Tarrytown, N.Y.) that discloses it contains 10 billion CFUs of its own branded Lactobacillus casei immunitas® (or L. casei DN-114 001) with L. bulgaricus, S. thermophyilus, and milk as the main ingredient per 93 ml serving. [1,8] (While admitting no wrong, Dannon settled a false or misleading advertising lawsuit in September 2009 that focused on claims of positive "immunity" benefits. Advertising will be reworded to say that DanActive® and Activa™ yogurt will "interact with your digestive tract's immune system.") 
Probiotics can be taken at least three hours following antibiotic injestion to prevent destabilization (killing the "good bacteria"). It may also be administered to rebuild flora following completion of a prescribed course of antibiotic treatement. As part of its nosocomial infection prevention program, Pacific Hospital of Long Beach follows up antibiotic treatments with yogurt. Probiotics can also be taken as part of a daily dietary supplement to combat the effects of processed foods and maintain healthy gut flora.
Probiotics are available in liquid, powder and capsule form. In some cases the bacteria is preserved with freeze-dried processing. The number of colony forming units (CFU) required varies with the type of bacteria ingested. A New Zealand product that contains Lactobacillus rhamnosus GG and Bifidobaterium animalis BB12 might be administered as follows: To increase immunity, doses have varied between 4-40 billion CFUs per day. For skin conditions, good results have been demonstrated at 20 billion CFUs per day (which is 3 capsules). Twenty billion CFUs is also a suitable dose following antibiotic therapy. 
Are probiotics for everyone?
Probiotics are generally considered safe but certain strains may cause flatulence or much more serious problems such as bacterial translocation across the gut wall in some individuals. It is wise to consult a physician before undertaking any significant dietary changes, particularly if one has digestive issues or any of the following conditions. Immunosuppressed individuals or those recently undergoing oral or gastrointestinal surgery or radiation therapy may contraindicate probiotics. 
Everything you wanted to know about probiotics
but were afraid to ask
Visit any of the links below for additional information. Over a dozen expert authors contribute to Probiotics.org. They attempt to cover everything related to prebiotics, probiotic supplements, yogurt and other probiotic foods, as well as specific product reviews. 
- Why you need to take the best Probiotic Supplement!, Corene Humphrey, zimbio.com
- Intestinal dysbiosis, Jule Klotter, BNET, FindArticles.com
- Gut flora, Wikipedia
- Male yeast infection: Can I get it from my girlfriend?, MayoClinic.com
- Male Yeast Infection, Yeast Infection Advisor
- 10 myths about probiotics, Mary Ellen Sanders, BNET, FindArticles.com
- Prebiotics vs. Probiotics, HealthCentral, MyIBDCentral.com
- Lactobacillus casei, Wiki, citizendium.org
- Dannon settles false advertising lawsuit over Activia, DanActive yogurt, LATimes.com
- The Leading Source Guide To Probiotics, Prebiotics, Yogurt, Acidophilus, Lactobacillus, Kefir and Other Sources of Friendly Bacteria and Yeast Organisms, Probiotic.org