Fosfomycin Several antimicrobial drugs have been tested for the effective treatment of<unk> . Fosfomycin is an antimicrobial agent that acts to inhibit UDP-N-acetylglucosamine enolpyruvyl transferase (MurA) which catalyzes one of the early steps of bacterial cell wall synthesis, and is effective against Gram-negative and -positive aerobic bacteria, such as<unk> . A meta-analysis of 17 studies investigating the clinical effectiveness of fosfomycin in four multidrug-resistant strains of<unk>  found 11 which reported that over 90% of bacterial isolates were susceptible to fosfomycin. The elevated level of antimicrobial activity by fosfomycin can be attributed to the fact that resistance to this antibiotic in<unk>  is chromosomally encoded and not plasmid-mediated. This causes a decreased capacity for survival in the bacteria. Bacteria that are naturally resistant to fosfomycin are less robust and less pathogenic. Tigecycline Tigecycline, a member of the glycylcyclines antibiotics, has proven to be an effective therapy against<unk>  that typically display tetracycline resistance, because tigecycline has a higher binding affinity with ribosomal sites than tetracycline has. Tigecycline is capable of killing almost all of the ESBLs and multidrug-resistant (MDR) E. coli isolates and the large majority of ESBL and MDR isolates of Klebsiella species. A 2008 review of 42 studies of in vitro susceptibility of bacteria to tigecycline showed that MDR K. pneumoniae and E. coli, including those that were<unk>  resistant, were susceptible more than 90% of the time. A limited number of patients have been treated with tigecycline, but the FDA has approved it in certain cases with synergies of other drugs. The limited number of patients indicates that more trials are needed to determine the overall clinical effectiveness. Although tigecycline is one of the first lines of defense against<unk> ase-producing isolates, negative clinical outcomes with tigecycline have occurred. Both urinary tract and primary blood infections can make tigecycline ineffective, because it has limited penetration and rapid tissue diffusion after being intravenously infused, respectively. Other antibiotics Alternatives to fosfomycin include nitrofurantoin, pivmecillinam, and co-amoxiclav in oral treatment of urinary-tract infections associated with extended-spectrum beta-lactamase. In a separate study,<unk>  were treated with colistin, amikacin, and tigecycline, and emphasizes the importance of using gentamicin in patients undergoing chemotherapy or stem-cell therapy procedures. While colistin had shown promising activity against<unk> ase-producing isolates, more recent data suggest a resistance to it is already emerging and it will soon become ineffective. Using another antibiotic concomitantly with<unk>  can help prevent the development of<unk>  resistance. One specific study showed a higher rate of<unk>  resistance when using meropenem alone compared with combination therapy with moxifloxacin. In addition, several drugs were tested to gauge their effectiveness against<unk>  infections. In vitro studies have shown that rifampin has synergistic activity against<unk> -resistant E. coli and K. pneumoniae. However, more data are needed to determine if rifampin is effective in a clinical setting. Several new agents are in development. The main areas where scientists are focusing is new β-lactamase inhibitors with activity against<unk> ases. Some of these include MK-7655, NXL104, and 6-alkylidenepenam sulfones. The exact way they affect the<unk> ases is unknown. Another experimental agent with activity against<unk>  is eravacycline.
Carbapenem-resistant enterobacteriaceae
Vancomycin-resistant Enterococcus
Shigatoxigenic and verotoxigenic Escherichia coli
Vancomycin-resistant Staphylococcus aureus
Methicillin-resistant Staphylococcus aureus
Rapid growing mycobacterium
Isolated levocardia
Enteroinvasive Escherichia coli