Critical by Robin Cook Page B

avoiding the back elevator. She'd started the day with a selfish desire to talk Jack out of his imminent surgery. Now she was worried about his well-being, maybe even his life. Among herself, Besserman, and Southgate, there were seven cases of fatal MRSA necrotizing pneumonia within three months at three hospitals, one of which Jack was scheduled to enter, and all run by the same company. And worse yet, these cases were occurring despite what Besserman had described as aggressive infection-control measures. Although Laurie was the first to admit that she didn't know too much about epidemiology, she knew enough to wonder if there might be a lethal, unknowing MRSA carrier, like a kind of Typhoid Mary in the Angels Healthcare organization who was inadvertently spreading MRSA as he or she went from hospital to hospital in the course of his or her job. Laurie wanted a lot of information, and as stubborn as Jack was, she wanted it fast if she hoped to influence his mind-set.
    The next stop was microbiology, which was part of the laboratory complex on the fourth floor. Laurie found the taciturn, sinewy microbiologist Agnes Finn in her small, windowless office. Of all the employees of the OCME, Agnes's appearance was the most stereotypic for working in a morgue from central casting's point of view. Her grayish-yellow coloring contributed; it was as if she never saw the light of day. Yet, of all the supervisors, Laurie found Agnes to be the most helpful by far, always willing to go out of her way. It was as if she had no life outside the OCME.
    Laurie sat down and explained the situation, which elicited from Agnes a mini-lecture on MRSA, including everything Besserman had to say and then some. She explained in detail how staphylococcus was such a pluripotent microbe, and perhaps the most adaptive and successful human pathogen.
    "When you think about it from the bacteria's point of view," Agnes said, "it is truly a superbug, capable of killing someone in a frightfully short time while the same strain is able to merely colonize an individual, usually just within the nares. This is a convenient location for the bacteria, because every time the carrier puts his or her finger in their nose, their fingers are contaminated from where it can be spread to the next person."
    "Is there an estimate as to how many people are so colonized?"
    "Absolutely. At any given time, a third of the world's population carries staph; that's about two billion people."
    "Good Lord," Laurie said. "Are there many strains of MRSA besides the hospital-acquired and the community-acquired?"
    "Very many," Agnes said. "And they are evolving all the time in people's noses and elsewhere, like moist skin surfaces, where they exchange genetic material."
    "How are the strains differentiated in the laboratory?"
    "Many ways," Agnes said. "Antibiotic resistance is one."
    "But that's not particularly sensitive, considering everything you've said."
    "That's correct. The more sensitive methods are all genetics-based: the simplest and most commonly employed being pulse-field gel electrophoresis, and the most complete being full genotyping. In between, there are a number of other sequence typing techniques all based on PCR."
    "What can you do here in microbiology?"
    "Only the simplest: antibiotic resistance."
    "If needed, where can the more complicated be done?"
    "The state reference lab can do the pulse-field gel electrophoresis. As for more specific typing, the CDC is the best bet. They are actually building a national library of MRSA strains, so they can give you a lot of information. They encourage submissions of isolates, and they can do it all. Of course Dr. Lynch in our DNA lab over in the new high-rise can do the various genetic typing, but we won't be able to tell you much about the specific strain."
    "Which of the genetic tests is the fastest? I'm up against a time constraint."
    "Truthfully, I don't know. What I do know is that our standard culture and antibiotic sensitives