Nemonoxacin is a non-fluorinated quinolone antibiotic in clinical development in an oral and intravenous formulation. It exhibits potent antibacterial activities against Gram-positive, Gram-negative, and atypical pathogens, especially methicillin-resistant Staphylococcus aureus. The molecule inhibits bacterial DNA synthesis by forming a ternary complex with a DNA molecule and gyrase and topoisomerase IV enzymes, thus blocking bacterial DNA supercoiling. Nemonoxacin is developed by TaiGen Biotechnology Company and has reached worldwide approval in 2014 and is marketed under the name Taigexyn®.

Arbekacin is a broad-spectrum aminoglycoside used to treat methicillin-resistant Staphylococcus aureus (MRSA). Arbekacin has antibacterial activities against high-level gentamicin-resistant Enterococci, multidrug-resistant Pseudomonas aeruginosa, and Acinetobacter baumannii et al. In a cell-free system, habekacin (arbekacin) interfered with polypeptide synthesis, caused codon misreading, and inhibited translocation of N-acetylphenylalanyl-tRNA from the acceptor site to the donor site on ribosomes. Arbekacin bound to both 50S and 30S ribosomal subunits. Arbekacin has been approved as an injectable formulation in Japan since 1990, under the trade name Habekacin, for the treatment of patients with pneumonia and sepsis caused by MRSA. Meiji Seika Pharma is developing an inhaled aerosol formulation of arbekacin for the treatment of hospital-acquired bacterial pneumonia and ventilator-associated bacterial pneumonia. Nobelpharma is developing an intravenous formulation of arbekacin sulfate, known as nonsense readthrough compound or NPC 14, for the treatment of Duchenne muscular dystrophy.

Olanexidine [1-(3,4-dichlorobenzyl)-5-octylbiguanide] (formerly OPB-2045), an antimicrobial agent exhibited antimicrobial activity against a wide range of bacteria, especially Gram-positive bacteria, was synthesized in 1997. To optimize its use as a topical antiseptic, olanexidine was converted to the gluconate salt. The resulting formulation (OPB) had more potent bactericidal activity against methicillin-resistant S. aureus and vancomycin-resistant enterococci in both in vitro and in vivo animal models than chlorhexidine and PVP-I. The mechanism of action was considered to be follows: olanexidine binds to the cell membrane, disrupts membrane integrity, and exerts its bacteriostatic and bactericidal activities by causing the irreversible leakage of intracellular components. At relatively high concentrations, olanexidine aggregates the cells through a protein-denaturing effect.

Dalbavancin is a second-generation lipoglycopeptide antibiotic that was designed to improve on the natural glycopeptides currently available, such as vancomycin and teicoplanin. Modifications from these older glycoprotein classes allowed a similar mechanism of action with increased activity and once weekly dosing. Its use is indicated for the treatment of acute bacterial skin and skin structure infections (ABSSSI) caused by the following gram-positive microorganisms: Staphylococcus aureus (including methicillin-susceptible and methicillin-resistant strains), S. pyogenes, S. agalactiae, and S. anginosus group (including S. anginosus, S. intermedius, and S. constellatus). Under the brand name DALVANCE Dalbavancin is indicated for acute bacterial skin and skin structure infections (ABSSSI) caused by designated susceptible strains of Gram-positive microorganisms. The bactericidal action of dalbavancin results primarily from inhibition of cell-wall biosynthesis. Specifically, dalbavancin prevents incorporation of N-acetylmuramic acid (NAM)- and N-acetylglucosamine (NAG)-peptide subunits from being incorporated into the peptidoglycan matrix; which forms the major structural component of Gram-positive cell walls. The large hydrophilic molecule is able to form hydrogen bond interactions with the terminal D-alanyl-D-alanine moieties of the NAM/NAG-peptides, which is normally a five-point interaction. Binding of dalbavancin to the D-Ala-D-Ala prevents the incorporation of the NAM/NAG-peptide subunits into the peptidoglycan matrix. In addition, dalbavancin alters bacterial-cell-membrane permeability and RNA synthesis.

Ramoplanin is a glycolipodepsipeptide antibiotic obtained from the fermentation of Actinoplanes sp. ATCC 33076 that exhibits activity against clinically important multi-drug-resistant, Gram-positive pathogens including vancomycin-resistant Enterococcus (VRE), methicillin-resistant Staphylococcus aureus (MRSA), and vancomycin-intermediate resistant Clostridium difficile. Ramoplanin was first isolated as a complex of three closely related components A1, A2, and A3. Preclinical studies have also demonstrated that ramoplanin exerts a rapid bactericidal effect on S. aureus biofilms and that a clinical vancomycin-resistant S. aureus strain containing the vanA gene was susceptible to ramoplanin. Ramoplanin blocks bacterial cell wall biosynthesis by interfering with peptidoglycan production. Ramoplanin inhibits the N-acetylglucosaminyltransferase-catalysed conversion of lipid intermediate I to lipid intermediate II, a step that occurs before the transglycosylation and transpeptidation reactions. Ramoplanin’s mechanism of action is distinct from that of glycopeptides. Unlike glycopeptides, ramoplanin does not complex with the D-Ala–D-Ala sequence of cell wall precursors. Ramoplanin is being developed for the targeted prophylaxis of recently treated patients with C. difficile infection (CDI) at high risk for infection relapse. Twelve Phase I studies, two Phase II studies (one in CDI and one in VRE) as well as one Phase III study (in VRE) have been conducted

Doxycycline hyclate (Vibramycin, Periostat, Vibra-Tabs) is salt of tetracycline antibiotic Doxycycline, that used to treat many kinds of infections, like dental, skin, respiratory, and urinary tract infections. It also treats acne, Lyme disease, malaria, and certain sexually transmitted diseases. Doxycycline hyclate is a light-yellow crystalline powder which is soluble in water, while doxycycline monohydrate is very slightly soluble in water. Doxycycline is bacteriostatic, inhibiting bacterial protein synthesis due to disruption of transfer RNA and messenger RNA at ribosomal sites. Doxycycline hyclate is indicated for use in the treatment of chronic adult periodontitis for a gain in clinical attachment, reduction in probing depth, and reduction in bleeding on probing.

Vancomycin is a branched tricyclic glycosylated nonribosomal peptide produced by the fermentation of the Actinobacteria species Amycolatopsis orientalis (formerly Nocardia orientalis). Vancomycin became available for clinical use >50 years ago. It is often reserved as the "drug of last resort", used only after treatment with other antibiotics had failed. Vancomycin has been shown to be active against most strains of the following microorganisms, both in vitro and in clinical infections: Listeria monocytogenes, Streptococcus pyogenes, Streptococcus pneumoniae (including penicillin-resistant strains), Streptococcus agalactiae, Actinomyces species, and Lactobacillus species. The combination of vancomycin and an aminoglycoside acts synergistically in vitro against many strains of Staphylococcus aureus, Streptococcus bovis, enterococci, and the viridans group streptococci. The bactericidal action of vancomycin results primarily from inhibition of cell-wall biosynthesis. Specifically, vancomycin prevents the incorporation of N-acetylmuramic acid (NAM)- and N-acetylglucosamine (NAG)-peptide subunits from being incorporated into the peptidoglycan matrix; which forms the major structural component of Gram-positive cell walls. The large hydrophilic molecule is able to form hydrogen bond interactions with the terminal D-alanyl-D-alanine moieties of the NAM/NAG-peptides. Normally this is a five-point interaction. This binding of vancomycin to the D-Ala-D-Ala prevents the incorporation of the NAM/NAG-peptide subunits into the peptidoglycan matrix. In addition, vancomycin alters bacterial-cell-membrane permeability and RNA synthesis. There is no cross-resistance between vancomycin and other antibiotics. Vancomycin is not active in vitro against gram-negative bacilli, mycobacteria, or fungi.

Methicillin sodium anhydrous is a sodium salt of methicillin (methicillin). Methicillin is an antibiotic formerly used in the treatment of bacterial infections caused by organisms of the genus Staphylococcus. Methicillin is a semisynthetic derivative of penicillin. It was first produced in the late 1950s and was developed as a type of antibiotic called penicillinase-resistant penicillin—it contained a modification to the original penicillin structure that made it resistant to a bacterial enzyme called penicillinase (beta-lactamase). Compared to other penicillins that face antimicrobial resistance due to β-lactamase, it is less active, can be administered only parenterally, and has a higher frequency of interstitial nephritis, an otherwise-rare adverse effect of penicillins. However, the selection of meticillin depended on the outcome of susceptibility testing of the sampled infection, and since it is no longer produced, it is also not routinely tested for anymore.

Methicillin sodium anhydrous is a sodium salt of methicillin (methicillin). Methicillin is an antibiotic formerly used in the treatment of bacterial infections caused by organisms of the genus Staphylococcus. Methicillin is a semisynthetic derivative of penicillin. It was first produced in the late 1950s and was developed as a type of antibiotic called penicillinase-resistant penicillin—it contained a modification to the original penicillin structure that made it resistant to a bacterial enzyme called penicillinase (beta-lactamase). Compared to other penicillins that face antimicrobial resistance due to β-lactamase, it is less active, can be administered only parenterally, and has a higher frequency of interstitial nephritis, an otherwise-rare adverse effect of penicillins. However, the selection of meticillin depended on the outcome of susceptibility testing of the sampled infection, and since it is no longer produced, it is also not routinely tested for anymore.