Broad Spectrum Antibiotic
A broad-spectrum antibiotic is a type of medication that is effective against a wide range of bacteria, including both Gram-positive and Gram-negative bacteria. These antibiotics are often used when the specific bacteria causing an infection are unknown, or when multiple types of bacteria are suspected. While broad-spectrum antibiotics can be effective in treating a variety of infections, they may also lead to antibiotic resistance and disruption of the body's natural microbiota.
6 Key excerpts on "Broad Spectrum Antibiotic"
eBook - ePubAntibiotics and Antimicrobial Resistance Genes in the Environment
Volume 1 in the Advances in Environmental Pollution Research series
- Muhammad Zaffar Hashmi, Muhammad Zaffar Hashmi(Authors)
- 2019(Publication Date)
- Elsevier(Publisher)
...Others influence protein building sites and DNA replication ingredients that are specific to bacteria (Vannuffel and Cocito, 1996). 19.1.3. Broad-spectrum antibiotics Antibiotics are divided into two subcategories. Narrow-spectrum antibiotics (NSAs) are those that perform active working in opposition to a selected group of bacterial and microbe types. NSAs are used for the exact infection when the contributory organism is acknowledged and will not affect a lot of microorganisms in the body as broad-spectrum antibiotics (BSAs) do. So, NSAs have less capability to root out a super infection. Examples of BSAs include Azithromycin as well as Clarithromycin, etc. (Ferretti et al., 2016). The phrase “broad-spectrum antibiotics or BSA” was initially used to delegate antibiotics that were efficient against both gram-positive as well as gram-negative bacteria, in contrast to penicillin, for example, which is helpful mainly against gram-positive bacteria, or streptomycin, which is vigorous chiefly against gram-negative organisms. The BSAs have an antimicrobial range that comprises some gram-positive and gram-negative organisms as well as larger viruses, certain rickettsiae, pleuropneumonia-like organisms, and protozoa (Almulhim and Alotaibi, 2018). The list of antibiotics, with use and abuse, is given in Table 19.1. 19.1.4. Vaccines block diseases Vaccination against diverse form of viral as well as bacterial diseases is an integral component of the communicable disease control worldwide. The purpose of vaccination is to decrease socioeconomic burden along with incidence of a particular disease. High-quality immunization results in inhibition of transmission of several vaccine preventable diseases. Immunization plays an integral role in controlling diseases, proven, for example, by the complete elimination of smallpox globally. Polio also has nearly been eradicated, although there are still some countries suffering from this disease...
eBook - ePub- Kristian Stromgaard, Povl Krogsgaard-Larsen, Ulf Madsen, Kristian Stromgaard, Povl Krogsgaard-Larsen, Ulf Madsen(Authors)
- 2016(Publication Date)
- CRC Press(Publisher)
...They are not effective against viral infections like common cold, most sore throats, and the flu. (FDA, 2015). Bactericidal antibiotics cause bacterial cell death. Bacteriostatic antibiotics inhibit bacterial growth without any loss in viability. Broad-spectrum antibiotics are active on a large number of bacterial species. Narrow-spectrum antibiotics are active against a small number of bacterial species. Antibiotic resistance is the acquired ability of bacteria to survive and multiply despite the presence of therapeutic levels of one or more antibiotics. Multidrug-resistant (MDR) is defined as acquired nonsusceptibility to at least one agent in three or more antimicrobial categories. Extensively drug-resistant (XDR) is defined as nonsusceptibility to at least one agent in all but two or fewer antimicrobial categories (i.e., bacterial isolates remain susceptible to only one or two categories). Pandrug-resistant (PDR) is defined as nonsusceptibility to all agents in all antimicrobial categories. Antimicrobial resistance mechanisms : Given the limited number of targets on which the known classes of antibiotics act, resistance mechanism are also well developed. The major types of clinically relevant resistance mechanisms are (1) modification of target structures/overproduction of target (2) enzymatic modification/inactivation of the antibiotic/elimination through the efflux pumps/decreased penetration of the antibiotic (3) bypassing a particular step in a pathway. Combination therapy involves the use of two or more agents that (1) inhibit different targets in different pathways (e.g., the cocktail of antituberculosis drugs [see Table 23.3 ]), (2) inhibit different steps in the same pathway (e.g., sulfamethoxazole/trimethoprim), and (3) inhibit the same target in different ways (e.g., streptogramins). 23.1.3 B ACTERIA AND THE N EED FOR N EW D RUGS Antibiotic resistance crept along ever since the wide and successful use of antibiotics...
eBook - ePubBacterial Pathogenesis
A Molecular Approach
- Brenda A. Wilson, Malcolm Winkler, Brian T. Ho(Authors)
- 2019(Publication Date)
- ASM Press(Publisher)
...First, the antibiotic must have few or no side effects. That is, it must be far more toxic to bacteria than to the human or animal body. This is known as the principle of differential toxicity. A second desirable characteristic, especially from the physician’s perspective, is a broad spectrum of activity against many different types of bacteria. This is important because it is usually not possible to determine the identity of the bacterium causing an infection from the symptoms alone and clinical testing is often not convenient or expeditious. In addition, clinical testing is costly. Bacterial infections often have nonspecific symptoms, such as fever, malaise, and pus formation. Since it takes time to isolate and identify the bacterium responsible for an infection, it is useful to have antibiotics that are effective against the entire range of bacteria capable of producing a particular set of symptoms. Especially in the case of serious, rapidly progressing diseases such as bacterial pneumonia and septic shock, there is only a narrow window of efficacy and not much margin for error in the selection of an effective antibiotic. Several other properties in addition to minimal side effects and maximum spectrum are required to make a good antibiotic. Antibiotics must have the appropriate bioavailability and pharmacokinetics to get to sites of infections. Bioavailability is a measurement of the rate or fraction of the drug that enters the systemic circulation and reaches the desired site of action. Pharmacokinetics is the tracking of the drug over time within the body, including its movement, distribution, metabolism, and excretion. For the same reasons that a broad-spectrum antibiotic is desirable, having excellent pharmacokinetics (uptake, distribution, and half-life properties) in humans or animals adds to the usefulness of the antibiotic...
eBook - ePub- José-Luis Capelo-Martínez, Gilberto Igrejas, José-Luis Capelo-Martínez, Gilberto Igrejas(Authors)
- 2019(Publication Date)
- Wiley(Publisher)
...These Gram‐negative pathogens are also frequently multidrug resistant (MDR) (resistant to ≱3 different antibiotic classes) and have become resistant to all or almost all of our antibiotic armamentarium including carbapenems and third/fourth‐generation cephalosporins – the most widely used drugs to fight these infections (Peleg and Hooper2010). Despite significant investments into antibiotic discovery in the past, no new antibiotic class with novel mode(s) of action against Gram‐negative bacteria (GNB) has been approved in half a century (Brown et al.2014). As a result there is an urgent demand to explore new approaches to combat antimicrobial resistance with the goal to preserve or revive existing antibiotics. In recent years several approaches including anti‐virulence strategies and antibiotic combination approaches as well as antibiotic–adjuvant combination approaches have been put forward with the goal to restore efficacy in antibiotics against antibiotic‐resistant pathogens (Li et al.2015; Tommasi et al.2015; Zygurskaya et al.2015; Brown and Wright2016; Silver2016; The Pew Charitable Trusts2016; Domalaon et al.2018c).18.2 Anti‐Virulence StrategyThe development of agents that are not bactericidal but indirectly inhibit the molecular pathway responsible for bacterial communication is a viable strategy to address the problem of antibiotic resistance (Williams2014; Brannon and Hadjifrangiskou2016; Dickey et al.2017). Compounds of this type are perceived to exert reduced evolutionary selective pressure and lower rates of resistance development (Rampioni et al.2014). One such example involves the blocking of bacterial quorum sensing (QS). QS is characterized by bacterial production release and group‐wide detection of autoinducer molecules as a mode of bacterial communication with their neighbors (Asfahl and Schuster2017)...
eBook - ePub- David B. Wilson, Hermann Sahm, Klaus-Peter Stahmann, Mattheos Koffas, David B. Wilson, Hermann Sahm, Klaus-Peter Stahmann, Mattheos Koffas(Authors)
- 2019(Publication Date)
- Wiley-VCH(Publisher)
...Macrolide antibiotics possess a similar activity profile to β‐lactam compounds and are commonly prescribed as substitutes for patients allergic to penicillin. Aminoglycosides offer an alternative activity profile relative to most β‐lactam and macrolide compounds and are, thus, used to treat a different spectrum of infectious diseases. Tetracycline compounds have shown activity across a broader array of microbial hosts and, as such, this and similar compounds are referred to as “broad spectrum” antibiotics. Table 8.2 Antibiotics discovered across decades and natural product classifications. Decade Antibiotic Classification 1920s Penicillin β‐Lactam 1940s Tetracycline Tetracycline 1940s Cephalexin β‐Lactam (cephalosporins) 1950s Erythromycin Macrolide 1960s Tobramycin Aminoglycoside 1970s Imipenem β‐Lactam (carbapenems) 1980s Daptomycin Cyclic lipopeptide 1980s Azithromycin Macrolide As will be described in more detail below, the microbes responsible for infectious disease possess either native or mutation‐based properties that render antibiotic compounds more or less effective. As such, antibiotic compound activity (as surveyed within Figure 8.2) is directed at appropriate microbial infectious disease targets. As additional examples, streptomycin is commonly used to treat tuberculosis, whereas daptomycin has shown activity toward the same types of bacteria susceptible to penicillins (termed Gram‐positive bacteria) with activity against an antibiotic resistant form of Staphylococcus aureus (termed methicillin‐resistant Staphylococcus aureus [ MRSA ]). The following sections will now go into more detail regarding the classifications of natural products that have emerged around biosynthetic mechanisms, compound structure, and therapeutic function. 8.2 β‐Lactams 8.2.1 History, Effect, and Application β‐Lactams represent a historic contributor to antibiotic natural product utility...
- Frank M. Aarestrup, Stefan Schwarz, Lina Maria Cavaco, Jianzhong Shen, Stefan Schwarz, Lina Maria Cavaco, Jianzhong Shen(Authors)
- 2018(Publication Date)
- ASM Press(Publisher)
...In contrast, this time span was extended to ≥15 years for narrow-spectrum agents, such as glycopeptides, which were used at distinctly lower quantities and only for specific applications. Multiple studies have also revealed that resistance to completely synthetic antimicrobial agents, such as sulfonamides, trimethoprim, fluoroquinolones, and oxazolidinones, can develop quickly (4 – 7). These observations underline the enormous flexibility of the bacteria to cope with less favorable environmental conditions by constantly exploring new ways to survive in the presence of antimicrobial agents. This chapter summarizes the latest information on resistance mechanisms and the mobile elements involved. It is a completely revised and updated version of the chapter that was published in 2006 (8). RESISTANCE TO ANTIMICROBIAL AGENTS Resistance to antimicrobial agents can be divided into two basic types, intrinsic resistance and acquired resistance (1, 3, 8, 9). Intrinsic resistance, also known as primary or innate resistance, describes a status of general insensitivity of bacteria to a specific antimicrobial agent or class of agents. This is commonly due to the lack or the inaccessibility of target structures for certain antimicrobial agents, e.g., resistance to β-lactam antibiotics and glycopeptides in cell wall-free bacteria, such as Mycoplasma spp., or vancomycin resistance in Gram-negative bacteria due to the inability of vancomycin to penetrate the outer membrane. It can also be due to the presence of export systems or the production of species-specific inactivating enzymes in certain bacteria, e.g., the AcrAB-TolC system or the production of AmpC β-lactamase in certain Enterobacteriaceae. In addition, some bacteria, such as enterococci, can use exogenous folates and are thus not dependent on a functional folate synthesis pathway. As a consequence, they are intrinsically resistant to folate pathway inhibitors, such as trimethoprim and sulfonamides (9)...
