either.â 5
Neil Fishman, president of the Society for Healthcare Epidemiology of America, is more blunt: âWe have lost our drug of last resort.â 6
Pan-resistant
Pseudomonas
and
Acinetobacter
are similarly dangerous.
Pseudomonas
has also begun to develop resistance to carbapenem antibiotics; the bacteria are now reliably treatable only by polymyxin.
Acinetobacter
,
E. coli
, and
Klebsiella
have also been promiscuously sharing a new plasmid, NDM-1, that confers resistance along a wide range of antibiotics, including carbapenem. âIn many ways, this is it,â says Timothy Walsh, a microbiologist and resistant bacteria specialist at Cardiff University in the UK. âThere are no antibiotics in the pipeline that have activity against NDM-1-producing Enterobacteriaceae. We have a bleak window of maybe ten years.â 7
Enterococcal organisms, once readily treatable, are so no longer. George Eliopoulos in the Division of Infectious Diseases at Beth Israel Deaconess Medical Center in Boston, Massachusetts, observes:
Ominously, in recent years, enterococci resistant to multiple antimicrobial agents have become increasingly prevalent in the hospital environmentâ¦. More than half of these enterococcal isolates were resistant to tetracycline, levofloxacin, and quinupristin-dalfopristin; 28 percent were resistantto ampicillin; and approximately 20 percent were nonsusceptible to vancomycin. From ICUs in the United States, even higher rates of vancomycin resistance have been reportedâ¦. Vancomycin resistance genes originating in enterococci have now been found in several clinical isolates of
S. aureus
. This validates concerns expressed more than a decade ago that VRE may serve as a reservoir of genes that could confer upon staphylococci resistance to glycopeptides, the principal antibiotics [remaining] for treatment of infections caused by methicillin-resistant strains [MRSA]. 8
There are
no
new antibiotics being developed to treat these resistant strains. The most recent, tigecycline, entered the market in 2005. It is active against resistant forms of
Acinetobacter
but not resistant
Pseudomonas
. Only tigecycline and that rather dangerous older antibiotic, polymyxin, can now treat
Acinetobacter
, and polymyxin itself has begun to encounter resistant forms of the bacteria. But then, so has tigecycline.
As Spellberg comments, âIf we did not have tigecycline, these infections would be essentially untreatable.â But as he continues, âtigecycline resistance spread within two years of the drugâs availability. Indeed, on a recent trip to visit a hospital on the East Coast, I was told that nearly all the hospitalâs
Acinetobacter
is already fully resistant to tigecycline.â 9
People who now enter hospitals, even for very minor treatments, are at serious risk of contracting untreatable infections. Over 70 percent of all pathogenic bacteria in hospitals are at least minimally resistant; the ones discussed herein are considerably more so, being resistant to most major groups of antimicrobials. As oncology nurse Sue Fischer says, âThese kids come in for a short treatment and the next day they complain about a pain in their side and the next day theyâre gone. We open them up and find their whole body shot through with resistant bacteria that have attacked nearly every organ. Nothing works to stop it and it happens as quick as that.â 10
Resistant Microorganisms: The Specifics
The first edition of this book covered 12 resistant pathogens that researchers were concerned about. There are 21 on this new list and that doesnât count the various subspecies in each genus that are now resistant (at least 40, not including variants) or several others that are lurking out there on the horizon. The problem, as many epidemiologists have warned, is increasing exponentially and there is no end in sight.
Some of these organisms, such as methicillin-resistant
Staphylococcus