According to a World Health Organization report published on Tuesday, the number of new antibiotics under development to combat the threat of multidrug-resistant infections is alarmingly low. Adding to the fear is the fact that it is likely that the speed of increasing resistance will outpace the slow drug development process.According to a news report, as of May, a total of 51 antibiotics and 11 biologicals–medical products often made from natural sources–are being developed."The idea is that biologicals could replace use of antibiotics, which could help in overcoming the resistance problem," Peter Beyer, an author of the report and senior adviser to the WHO's Department of Essential Medicines and Health Products, wrote in an email.Apparently, this number of potential new drugs should be sufficient yet it is not nearly enough.First, just 33 of the antibiotics in the pipeline target priority pathogens. This year, the WHO published a list of a dozen ‘priority pathogens,’ 12 separate families of antibiotic-resistant bacteria that pose the greatest threat to human health.Among the priority pathogens is drug-resistant tuberculosis, which kills about 250,000 people around the world each year, and a variety of multidrug-resistant strains -- Acinetobacter, Pseudomonas, and various Enterobacteriaceae -- which are responsible for infections in hospitals and nursing homes and among patients whose care requires ventilators and catheters."It is difficult to speculate why companies develop specific new medicines," Beyer noted. "But in general many new treatments do not necessarily constitute advances over existing treatments."