The discovery of penicillin by Fleming in 1929 opened an entire new way bto control bacterial infections. The industrial production of penicillin in 1940 and the subsequent introduction of new antibiotics into medical application saved many lives and raised hopes for permanent control of pathogens. However, the continuous and increasing use of antibiotics led to the emergence of pathogenic bacteria resistant to many of these anti-infectiva. During antibiotic treatment, these resistances are probably generated by hypermutating strains. An elevated number of strains exhibiting high mutation frequencies have recently been reported in the population of many pathogenic bacteria, for example, Pseudomonas aeruginosa in the cystic lung. The majority of naturally occurring strong mutators possessing up to 1,000-fold higher than the normal mutation rates have an advantage against normal strains for the selection of some antibiotic-resistant mutations. Horizontal gene transfer is also enhanced in mismatch repair-defective mutators, facilitating the spread of drug resistance in bacteria. However, hypermutators have a price to pay for their fitness, which is not the case for weak mutators found in many clinical isolates. Furthermore, the sewage systems are loaded with antibacterial excreted by humans and animals treated for prophylactic and therapeutic reasons. Several classes of chemotherapeutics have been found in the outlets of sewage treatment plants and can be detected in rivers. It has been hypothesized that these pharmaceuticals as well contribute to the increasing number of resistant pathogens.

It can be inferred from the passage that the author agrees with which of the following about pathogens?

A. The hypermutation of pathogenic organisms supports the notion that many antibiotics do more harm than good.
B. Some of the measures that people take to preserve their health in fact threatens their health.
C. Pharmaceuticals contribute to the resistance of pathogenic bacteria.



It can be inferred that the author of the passage mentions “a price to pay” primarily in order to

A. help explain why hypermutators are usually the most harmful pathogens
B. identify one weakness in the argument that all pathogens create disease
C. indicate how hypermutators’ resistance to antibiotics has been steadily increasing
D. help account for how weak mutators generally outnumber hypermutators
E. suggest that hypermutators’ resistance to antibiotics does not always help them thrive