Shigella, Children, and Antibiotic Resistance

In the developed world, shigellosis, a diahrreal disease caused by the bacterial species Shigella, typically isn't considered dangerous, even though it makes about 450,000 ill in the U.S. To shorten the length of illness and to reduce potential infection of other people, antibiotics are typically prescribed, usually cotrmoxazole or ampicillin. However, recent shigellosis outbreaks are cause for concern (italics mine):

Surveillance data for antimicrobial resistance among all S. sonnei isolates received by NARMS during 1999--2003 indicated that 80% of the isolates were resistant to ampicillin and 47% to TMP/SMX [cotrimoxazole]; 38% were resistant to both drugs (6). In the two outbreaks described in this report, resistance to both ampicillin and TMP/SMX was 89%, complicating shigellosis treatment in these communities.

In other words, the 'empirical therapy'--the educated guess doctors make before they have a full laboratory workup (which takes 48-96 hours)--won't work. Unfortunately, other drugs are difficult to use in children (or simply not approved):

Although ampicillin and TMP/SMX have been the drugs of choice for treatment of shigellosis, current resistance patterns limit the use of these antibiotics. Fluoroquinolones are an effective alternative for adults but are not approved by the Food and Drug Administration for shigellosis treatment in children aged <18 years. Macrolides, particularly azithromycin, also are recommended by the American Academy of Pediatrics for treatment of shigellosis, although data about clinical effectiveness are limited, and no standardized guidelines for monitoring azithromycin resistance among shigellae are currently available (7). In addition, azithromycin is excreted in stool over an extended period. Follow-up stool cultures will not yield accurate results until azithromycin is no longer being excreted; therefore, the time required for follow-up testing might be prolonged (8).

And, as always, nineteenth century medicine still is quite useful:

The emergence of MDR [multidrug resistant] shigellosis highlights the importance of prevention and rapid control of outbreaks. Appropriate handwashing and diapering practices are critical in minimizing the transmission of shigellosis in day care centers (9). Scheduling handwashing sessions on arrival at the day care center, before meals, or after playing outdoors; supervising handwashing among young children; and eliminating water play areas have been used to reduce the spread of shigellosis within day care centers and to the community (10). Forming cohorts of convalescing children (e.g., asymptomatic children who are culture-positive), by allowing them to attend the day care center but excluding them from interacting with other well children, also has been used to control outbreaks associated with day care centers; however, state regulations in these three states do not allow such measures. Given the current rates of resistance to ampicillin and TMP/SMX, the uncertain safety of administering fluoroquinolones to children, the difficulties in monitoring azithromycin resistance, the absence of an appropriate vaccine, and the unclear benefits of exclusion policies in day care centers, public health measures should focus on prevention of shigellosis outbreaks through appropriate hygiene practices and, where possible and allowed by state regulations, forming cohorts of convalescing children in day care centers.

Whether it's norovirus or Shigella, shit (literally) is bad for you. Wash your damn hands! (and those of the wee'uns too).

One more point: a major weakness of the U.S. public health infrastructure has been that public health is primarily a state (and local) responsibility. But these resistant shigellosis outbreaks happened in three different states (Kansas, Kentucky, and Missouri) and require a coordinated, legislative response (i.e., isolating sick children). There is a role for federal policy intervention, because bacteria and viruses really don't care about state boundaries.