Yeast overgrowth in the throat and mouth can be detected by a yellowish or sometimes white growth on the tongue may cause sore throat. Prolonged antibiotic therapy may also stimulate the proliferation of yeast in the gastrointestinal tract. Fermentation of sugars in the gastrointestinal tract will inevitably lead to the production of acids and alcohol. Hence such individuals may experience episodes of lightheadedness, headaches and dizziness due to alcohol, while the acids are responsible for gas formation, pain or heart burn in the stomach region.
Yeasts also cause enzymatic digestion of the fats and proteins as a necessity for their attachment on the mucosal lining. So many studies have associated Clostridium difficile with diarrhea among patients undergoing a long term antibiotic therapy. Nearly all classes of antibiotics cause pseudomembranous colitis in a select minority of patients. Flouroquinolone antibiotic family (Gatifloxacin, Lomefloxacin, Levofloxacin, Ciprofloxacin, Trovafloxacin and Sparfloxacin) and Clindamycins have been linked to the recent outbreaks of virulent Clostridium difficile associated infections.
Even though the exact mechanisms through which antibiotics cause gastrointestinal symptoms in pediatric patients are not known, Clostridium difficile toxins have been widely incriminated in pseudomembranous colitis. In the absence of frank colitis, the bacteria remain the major culprit in antibiotic associated diarrhea. In the absence of C. difficile or its enterotoxin, other colonic bacterial flora may also be responsible for diarrhea. Apart from the altered flora hypothesis, the exact bio-chemical processes or physiological processes that produce diarrhea still remain obscure (Kramer et al 1985).
Other studies have also demonstrated that other than eliminating the gastrointestinal microbiota, antibiotics simplify intestinal microbiota. The extent of adverse effects caused varies and is dependent on the antibiotics included in the therapy, the extent of their inactivation in the gastrointestinal tract, their pharmacokinetics as well as a host of other in vitro activities. Antibiotics such as clindamycin and penicillin drastically reduce the Bacteriodes spp, bifidobacteria, anaerobic cocci and lactobacilli populations.
Other antibiotics like chloramphenicol, cefotaxime, and metronidazole have limited effect on intestinal microbiota populations (Wilson 2005). Currently, in excess of 70% of the world’s populace experience lactose indigestion owing to intestinal lactase inactivity. The result of maldigestion manifests as abdominal complaints and diarrhea. Patients under antibiotic therapies experience lactose intolerance. Several studies have postulated that lactose intolerance may be due to alteration of intestinal microflora which leads to the disruption of metabolic adaptation to the arrival of lactose.
Another cause of lactose intolerance may be irritable bowel syndrome (Briet et al 1997). However, the osmotic load that is caused by large quantities of undigested lactose is the main mechanism behind the symptoms of lactose intolerance. The colonic microbiota plays an integral role in processing of ingested lactose in the colon. Consequently, the capacity of the colonic microbiota to effectively process lactose is determined by their composition and metabolic activity. Thus, fermentation capacity has a direct relationship with lactose intolerance.
The fermentation of lactose begins by its hydrolysis to glucose and galactose. Fermentation o glucose and galactose produces a host of biochemical intermediates like formate, succinate and lactate, as well as the end product metabolites like propionate, acetate, butyrate, gases (carbon dioxide, oxygen and methane) and biomass. The balance between the capability of colonic microflora to effectively ferment lactose and the capability of the colon to effectively eliminate the metabolites influences fermentation of lactose, hence lactose intolerance.
The composition of microbiota is directly influenced by the presence of antibiotics leading to low fermentation (He et al 2006). Antibiotic resistance is emerging as a serious public health problem. Antibiotic resistance is mainly causes by two major categories of antibiotic misuse: widespread use of antibiotics in livestock production and over prescription of antibiotic therapies in clinical medicine. As opposed to animal production where a vast majority of antibiotics used serve no therapeutic purpose, a select minority are important in the prevention and treatment of a host of animal bacterial diseases.
Even though agricultural usage of antibiotics accounts is the main culprit in the worrying antibiotic resistance trend, legitimate use of antibiotics in human medicine has been constantly weighed down by over prescription and widespread misuse. Almost half, of the antibiotics used in animal husbandly are similar to the ones utilized in human medicine. This close similarity unquestionably accounts for the emergence of new bacterial strains which are resistant to antibiotic drugs. Apart from increasing the cost of medical and health care delivery, antibiotic resistance increasingly threatens the lives of millions worldwide.
Human overuse of antibiotics in inappropriate treatments, for instance against diseases of viral aetiology, that are unresponsive to bacterial therapies is a sore throat in medical practice. Long term inappropriate prescriptions of antibiotics in treating respiratory infections and colds and other self limiting illnesses is to blame for the dangerous effects on human medicine. In the United States alone, in excess of 97% of physicians prescribe antibiotics in ear infections even though such infections do not require antibiotic therapy.
Apart from directly contributing to antibiotic resistance, inappropriate use and overuse of antibiotics by humans is paving way for the emergence of new pathogens. Antibiotic resistance is basically an evolutionary process based on natural selection for certain species of organisms which enhances the ability of such microorganisms to survive in a physiological environment effectively dosed with antibiotics. Antibiotics like Erythromycin and Penicillin which were in the recent past very effective in one time cures have now been rendered less effective owing to the gradual development of antibiotic resistance in various bacterial species.
The mode of action of several antibiotics is an exertion of selective pressure on bacterial growth and consequently the limiting of bacterial proliferation. The main antibiotic resistance mechanism is derived from inherited genetic characteristics. Antibiotic resistance genes guarantee survival in non lethal concentrations of antibiotics. Additional mutations may further aid the survival of the bacteria in concentrations that had earlier on been lethal (Martinez 2008).
While the underlying molecular mechanisms conferring bacterial resistance vary from species to species, intrinsic antibiotic resistance is conferred by the bacterial genetic make-up. This results from the failure of the bacterial chromosome to encode the protein targeted by antibiotics. Bacteria can also result from mutations in the bacterial chromosome or when the bacteria acquire extra chromosomal DNA. This is what is known as acquired antibiotic resistance. These resistance mechanisms are transferable between select bacterial species.
Horizontal genetic exchange principally occurs through exchange of plasmids in which genes that encode antibiotic resistance are contained. Plasmids have the capacity to encode antibiotic resistance genes with the ability to confer co-resistance to multiple antibiotic drugs (Andersson 2005; Martinez 2008). Research has conclusively determined that antibiotic overuse and misuse directly exacerbates the problem of antibiotic resistance. Sub optimal antibiotic prescriptions, use of antibiotics in animal husbandry and non therapeutic usage of these drugs are key problems that need to be conclusively addressed.
Inappropriate usage of antibiotics through self prescriptions that completely disregards laid down prescription guidelines creates an advantageous environment for resistance and cross resistance to multiple antibiotics. The net result is an increase in antibiotic resistance and a decrease in the effectiveness of antibiotics in the treatment and management of diseases of bacterial aetiology. This is the main reason why several organizations have joined the advocacy for a more stringent regulatory climate. Research has established that antibiotic overuse predisposes individuals to the risk of cancer.
The frequency of antibiotic use has been linked to an increase in the risk of developing breast cancer. Several research studies have established that a link exists between the frequency of antibiotic use and the incidence of non-Hodgkin’s lymphoma. Even though such associations have not been conclusively proven, the indication that the frequency of antibiotic usage directly impacts on ones chances of contracting cancers, such as breast, ovary, prostrate, lung and colon cancer, over a period of time is a matter of grave concern (Kilkkinen 2008).
The unnecessary and gratuitous use of antibiotics in human medicine and animal husbandly should be urgently addressed owing to the potential such practices poses to public health. Antibiotics enhance health when they are properly used, but when they are improperly used, antibiotics can also cause serious health effects. Use of antibiotics has been incriminated in the development of allergies. In the United States of America, approximately 10% of the entire populace exhibit marked sensitivity to antibiotic drugs. Moreover prolonged use of antibiotics also causes Vitamin K deficiency (Esmiger 1994).
Conclusion Diarrhea, adverse gastrointestinal symptoms, lactose intolerance, antibiotic resistance and cancer risk are manifestations which typify the plethora of adverse side effects of antibiotics that are more often than not buried deep under the gloss of antibiotic efficacy. Generally, antibiotic therapy associated adverse symptoms usually disappear when treatment with antibiotics is discontinued. Even though, these symptoms are basically mild, the serious discomfort and the risk to more serious diseases like cancer is a grave concern for public health and health care delivery in general.
Strict antibiotic usage guidelines should be put in place together with stringent circumspection protocols not only to alleviate adverse effects but also to reduce the threat of antibiotic resistance. Better therapeutic decisions are an integral component of comprehensive measures taken to tackle all these public health risks.
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