Antimicrobial agents are products used in fighting diseases and infections caused by pathogens. There are different types of antimicrobial agents. Some of these include penicillin, combinations of beta-lactam with beta-lactamase inhibitor, cephalosporin, monobactams, fluoroquinolones, macrolides and ketolides, aminoglycosides among others. Bacteria causes bacterial infections whereas viruses are associated with viral infections. Continuous use of antimicrobial agents results to drug resistance of the disease causing microbes and this can be overcame by proper identification of viral and bacterial infections when selecting the antimicrobial agents. The paper discusses some of the antimicrobial agents, including the differences of bacterial and viral infections and factors to consider when selecting the treatment regime.Categories of Anti-microbial AgentsPenicillinPenicillin were first developed in 19th century and were used in fighting against staphylococcal and streptococcal disorders. Since 1928, numerous scientific studies have led to the development of synthetic penicillin with an objective of addressing the problem of resistance. Penicillin are an important class of antimicrobials and are classified basing on their spectra of activity.Beta-Lactam/Beta-Lactamase Inhibitor CombinationsBeta-lactamase inhibitor performs a crucial role of preventing the synthesis of the beta-lactam by microbes which produces the enzyme, and this improves the antibacterial activity. The combination of beta lactam with beta-lactamase inhibitor produces a medicinal product suitable for treating beta-lactamase disease causing micro-organisms like Bacteroides fragilis, S.aureus and Haemophilis influenzae. CephalosporinThese belong to the beta-lactam group and are similar to penicillin. Substitutions which occur on the parent group, 7-aminocephalosporanic acid lead to production of compounds with varying spectra activities and pharmacokinetic properties. The cephalosporin are classified into different “generation” and the classification is done basing on the spectrum of activity of the antimicrobials. The progression from the first generation to the fourth one generally portrays a rise in gram-negative coverage and a reduction in gram-positive activity.MonobactamsThese are a special category of beta-lactams containing four rings but deficient in the fifth and sixth members which is similar to other beta-lactams. Most of the information and available literature relates to Azactam (Aztreonam) because it is the only agent of monobactams class which is commercially available. Azactam primarily acts against gram-negative organisms including but not limited to Pseudomonas.FluoroquinolonesThe fluoroquinolones have grown to be a popular and dominant category of antimicrobial agents since 1990. The available evidence shows that it has grown rapidly than any other antimicrobial agent and thus it is of much interest to the pharmaceutical companies. The most commonly prescribed drugs of fluoroquinolone class include ciprofloxacin, moxifloxacin and levofloxacin.Macrolides and KetolidesA prototypical macrolide by the name E-Mycin (Erythromycin) has been applied in treating multiple diseases over the years. However, currently there is a diminishing use of the drug due to its GI side effects. The toxicity has been applied in treating people suffering from diabetic gastroparesis. Azithromycin and clarithromycin are newer macrolide agents invented which contain improved GI tolerance and longer half-lives. The ketolides class contains only one agent, telithromycin. The antibacterial coverage and the mechanism of action of telithromycin is similar to that of macrolides, although the two products are entirely different.AminoglycosidesThese class of drugs remain important in therapeutic interventions despite the fact that there has been development of many new antibiotics. The aminoglycosides are toxic and this accounts for one of the major drawbacks towards the use of the products. However, a modified dosing regimen has been introduced which requires the use the products in once-daily dosing or even extended-interval dosing for several disorders. The process has provided an approach of making maximum use of the therapeutic effects of the drug while reducing the risks of toxicity at the same time.Differences between Bacterial and Viral InfectionsAs the name suggests, bacterial infections are caused by bacteria whereas viral infections are caused by viruses. Therapeutic interventions for different diseases differ and thus it is important to know the infections caused by viruses and bacteria. For instance, whooping cough, ear infections, urinary tract infection (UTI), and strep throat are bacterial infections. On the other hand, common cold, bronchitis, HIV/AIDS, flu and chickenpox are viral diseases. Bacterial infections are more severe and can cause detrimental effects in the body if not treated. However, the good news is that there are antibiotics available for treating bacterial infections. On the other hand, viral infections such as HIV/AIDS have no cure, the only medications available limit the multiplication of the virus.Why proper identification of viral and bacterial infections is key to selecting the proper antimicrobial agentProper identification of bacterial and viral diseases is essential to the selection of a proper antimicrobial agent because it assists in avoiding drug resistance of disease-causing micro-organisms. Resistance shows that continuous use of antimicrobial agents has led to development of resistance among most of the microbes which cause bacterial and viral infections. Therefore, poor identification of bacterial and viral diseases can lead to failure in therapeutic interventions for such disorders. Appropriate identification ensures proper selection of the most suitable vaccine which prevents the microorganisms from causing diseases.ConclusionThere are various categories of antimicrobial agents. Some of these include penicillin, cephalosporin, monobactams, fluoroquinolones, aminoglycosides, macrolides and ketolides among others. The list is long and only a few have been discussed. Bacteria cause bacterial infections whereas viruses cause viral diseases. Whooping cough, UTI, strep throat and ear infections are some examples of bacterial infections while chickenpox, HIV/AIDS, flu and bronchitis are examples of viral disorders. It is essential to ensure proper identification of bacterial and viral infections when selecting the antimicrobial agent because it helps in countering the problem of drug resistance among disease causing microbes.