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.

LEFAMULIN is a pleuromutilin antibiotic under development for the treatment of community-acquired bacterial pneumonia, as well as acute bacterial skin and skin structure infections. It inhibits bacterial protein synthesis by binding to the peptidyl transferase center of the 50S ribosome, resulting in the cessation of bacterial growth.

Omadacycline is a tetracyclin-derivative antibiotic, originated in Tufts University, and later co-developed by Merck and Paratek Pharmaceuticals. The drug was approved for treatment of community-acquired pneumonia, and for treatment of acute bacterial skin and skin structure infections. Omadacycline tosylate is available as tablets and in injectable form.

Rifamycin SV is a derivative of antibiotic rifamycin B (the natural fermentation product of S. mediterranei broths). The primary target of rifampicin on whole bacteria is the synthesis of RNA. Rifamycin belongs to the ansamycin class of antibacterial drugs and acts by inhibiting the beta subunit of the bacterial DNA-dependent RNA polymerase, blocking one of the steps in DNA transcription. This results in inhibition of bacterial synthesis and consequently growth of bacteria. Rifampicin exhibits bactericidal activity on Gram-positive and Gram-negative bacteria and on mycobacteria. Rifamycin SV MMX® (AEMCOLO), a non-absorbable rifamycin antibiotic formulated using the multi-matrix system, was designed to exhibit its pharmacological action on the distal small intestine and colon. AEMCOLO is indicated for the treatment of travelers’ diarrhea (TD) caused by non-invasive strains of Escherichia coli in adults.

Delafloxacin (CAS registry number 189279-58-1) was described as WQ-3034 by Wakunaga Pharmaceutical Co., Ltd., Osaka & Hiroshima, Japan. It was first licensed in 1999 to Abbott Park, IL, and further developed as ABT-492. Delafloxacin (Baxdela), a fluoroquinolone antibiotic, is currently being developed by Melinta Therapeutics. It is a novel investigational fluoroquinolone in development for the treatment of uncomplicated gonorrhea, and acute bacterial skin and skin structure infections. Delafloxacin shows MICs remarkably low against Gram-positive organisms and anaerobes and similar to those of ciprofloxacin against Gram-negative bacteria. It remains active against most fluoroquinolone-resistant strains, except enterococci. Its potency is further increased in acidic environments (found in many infection sites). Delafloxacin is active on staphylococci growing intracellularly or in biofilms. Delafloxacin is a dual-targeting fluoroquinolone, capable of forming cleavable complexes with DNA and topoisomerase IV or DNA gyrase and of inhibiting the activity of these enzymes in both Gram-positive and Gram-negative bacteria. On Oct 24, 2016, Melinta Therapeutics Submitted Baxdela New Drug Application for hospital-treated skin infections.

Tedizolid (also known as TR-700, DA-7157) as is an active compound, which is produced by plasma or intestinal phosphatases, after administration of the drug, tedizolid phosphate either orally or intravenously. The mechanism of action of tedizolid occurs through inhibition of bacterial protein synthesis by binding to the 23S ribosomal RNA of the 50S subunit, thereby preventing the formation of the 70S initiation complex and inhibiting protein synthesis.

Oritavancin is an glycopeptide antibiotic with bactericidal activity effective in treating infections caused by Gram-positive organisms. It treats complicated skin and skin structure infections. This drug demonstrates similar activity to vancomycin, but it has stronger activity against Staphylococcus and Enterococcus. The pharmacokinetics and pharmacodynamics of oritavancin appear to be favourable and once-daily dosing is likely. The incidence of multi-drug resistant bacteria is increasing and explorations into additional treatment options are essential. Oritavancin is marketed under the brand name Orbactiv. Orbactiv is indicated for the treatment of adult patients with acute bacterial skin and skin structure infections caused or suspected to be caused by susceptible isolates of designated Gram-positive microorganisms. Oritavancin has the following mechanism of action: 1) Inhibition of the transglycosylation (polymerisation) step of cell wall biosynthesis by binding to the stem peptide of peptidoglycan precursors 2) Inhibition of the transpeptidation (crosslinking) step of cell wall biosynthesis by binding to the peptide bridging segments of the cell wall 3) Disruption of bacterial membrane integrity, leading to depolarisation, increased permeability and rapid cell death.

Ceftaroline fosamil is a 5th generation cephalosporin with an in vitro spectrum of activity including Streptococcus agalactiae, penicillin- and cephalosporin-resistant S. pneumoniae, S. pyogenes, methicillin-susceptible S. aureus and methicillin-resistant S. aureus, Haemophilus influenzae, Klebsiella oxytoca, K. pneumoniae and Moraxella catarrhalis. Ceftaroline fosamil (TAK-599 or PPI-0903), the prodrug of the active metabolite, ceftaroline, was synthesized by Takeda Pharmaceutical Co., Ltd and developed by Cerexa, Inc. and Forest Laboratories, Inc. It is currently approved by the FDA for the treatment of acute bacterial skin and skin structure infections (ABSSSI) and community-acquired bacterial pneumonia (CABP) in adults. Ceftaroline fosamil is marketed under the brand name TEFLARO®, indicated in adult and pediatric patients 2 months of age and older for the treatment of acute bacterial skin and skin structure infections (ABSSSI) caused by susceptible isolates of the following Gram-positive and Gram-negative microorganisms: Staphylococcus aureus (including methicillin-susceptible and ‑resistant isolates), Streptococcus pyogenes, Streptococcus agalactiae, Escherichia coli, Klebsiella pneumoniae, and Klebsiella oxytoca. TEFLARO is also indicated in adult and pediatric patients 2 months of age and older for the treatment of community-acquired bacterial pneumonia (CABP) caused by susceptible isolates of the following Gram-positive and Gram-negative microorganisms: Streptococcus pneumoniae (including cases with concurrent bacteremia), Staphylococcus aureus (methicillin-susceptible isolates only), Haemophilus influenzae, Klebsiella pneumoniae, Klebsiella oxytoca, and Escherichia coli. Ceftaroline provides in vitro bactericidal activity against methicillin-, vancomycin-, daptomycin-, and linezolid-resistant Gram-positive organisms and select Gram-negative pathogens. The pharmacodynamics of ceftaroline is similar to other β-lactam agents. Ceftaroline exhibits a favorable adverse effect profile and is generally well tolerated. The bactericidal action of ceftaroline is mediated through binding to essential penicillin-binding proteins (PBPs). Ceftaroline is bactericidal against S. aureus due to its affinity for PBP2a and against Streptococcus pneumoniae due to its affinity for PBP2x.

TELAVANCIN (VIBATIV®) is a lipoglycopeptide antibacterial that is a synthetic derivative of vancomycin. It exerts concentration-dependent, bactericidal activity against Gram-positive organisms in vitro. TELAVANCIN (VIBATIV®) inhibits cell wall biosynthesis by binding to late-stage peptidoglycan precursors, including lipid II. It also binds to the bacterial membrane and disrupts membrane barrier function. TELAVANCIN (VIBATIV®) is indicated for the treatment of adult patients with complicated skin and skin structure infections caused by susceptible isolates of the following Gram-positive microorganisms: Staphylococcus aureus (including methicillin-susceptible and -resistant isolates), Streptococcus pyogenes, Streptococcus agalactiae, Streptococcus anginosus group (includes S. anginosus, S. intermedius, and S. constellatus), or Enterococcus faecalis (vancomycin-susceptible isolates only). It is also indicated for the treatment of adult patients with hospital-acquired and ventilator-associated bacterial pneumonia (HABP/VABP), caused by susceptible isolates of Staphylococcus aureus (both methicillin-susceptible and -resistant isolates). It should be reserved for use when alternative treatments are not suitable.

Tigecycline (INN) is an antibiotic used to treat a number of bacterial infections. It is a first in class glycylcycline that is administered intravenously. For the treatment of infections caused by susceptible strains of the designated microorganisms in the following conditions: Complicated skin and skin structure infections caused by Escherichia coli, Enterococcus faecalis (vancomycin-susceptible isolates only), Staphylococcus aureus (methicillin-susceptible and -resistant isolates), Streptococcus agalactiae, Streptococcus anginosus grp. (includes S. anginosus, S. intermedius, and S. constellatus), Streptococcus pyogenes and Bacteroides fragilis. Complicated intra-abdominal infections caused by Citrobacter freundii, Enterobacter cloacae, Escherichia coli, Klebsiella oxytoca, Klebsiella pneumoniae, Enterococcus faecalis (vancomycin-susceptible isolates only), Staphylococcus aureus (methicillin-susceptible isolates only), Streptococcus anginosus grp. (includes S. anginosus, S. intermedius, and S. constellatus), Bacteroides fragilis, Bacteroides thetaiotaomicron, Bacteroides uniformis, Bacteroides vulgatus, Clostridium perfringens, and Peptostreptococcus micros. Tigecycline, a glycylcycline, inhibits protein translation in bacteria by binding to the 30S ribosomal subunit and blocking entry of amino-acyl tRNA molecules into the A site of the ribosome. This prevents incorporation of amino acid residues into elongating peptide chains. Tigecycline carries a glycylamido moiety attached to the 9-position of minocycline. The substitution pattern is not present in any naturally occurring or semisynthetic tetracycline and imparts certain microbiologic properties to tigecycline. In general, tigecycline is considered bacteriostatic; however, TYGACIL has demonstrated bactericidal activity against isolates of S. pneumoniae and L. pneumophila. In vitro studies have not demonstrated antagonism between tigecycline and other commonly used antibacterials.