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As my community battles another large Shigella outbreak, I wanted to point out a few aspects of the infection that are often overlooked.
An estimated 450,000 cases of shigellosis occur every year in the United States, the majority among children who are not yet toilet trained. Here in the Kansas City area, we've had an ongoing Shigella sonnei outbreak since November 2009, with more than 250 cases diagnosed to date.
While the diarrhea is usually mild and self-limited, it is highly contagious through the fecal-oral route. Treatment is recommended for confirmed cases, both to stem transmission and to shorten disease duration. Of concern, resistance to trimethoprim-sulfamethoxazole has risen dramatically, from 47% in 1999–2003 to 89% in 2006. Ampicillin resistance also jumped, from 80% to 86%, while strains resistant to both drugs rose from 38% to 89% (MMWR 2006;55:1068–71).
However, azithromycin remains a good choice for treatment and is recommended in the Red Book as a potential treatment option for shigellosis. Dosing is 10 mg/kg one time on day 1 and then 5 mg/kg once a day for 4 more days (maximum 500 mg on day 1 and 250 mg thereafter). Microbiology labs do not routinely report azithromycin-susceptibility data, but randomly selected isolates have been tested during our current outbreak and thus far all are susceptible.
Most isolates are also susceptible to both ceftriaxone and ciprofloxacin, but both of those drugs are approximately five times more expensive than azithromycin is, and fluoroquinolones aren't approved for treating shigellosis in children younger than 18 years of age unless there are no other choices.
Some data also support the use of oral cephalosporins, but eradication rates are lower than with other drugs, so they currently are not recommended.
The last Shigella outbreak in Kansas City, in 2005, involved more than 400 cases over a period of 6 months and also featured a multidrug-resistant strain. Most children had mild disease, but we encountered an obstacle in that Missouri state law requires two negative stool cultures after treatment before the child can return to school or day care, which typically took 2–3 weeks to achieve. Appropriate treatment was often delayed because of empiric therapy with drugs to which strains were resistant and/or preauthorization requirements for using alternative drugs. Getting the families to come back for the repeat culture also was often a challenge.
There are few data to support exclusion policies that mandate two negative cultures. In contrast, some data suggest that such policies prolong the outbreak, in part because some parents will simply move their child to another day care center without mentioning the infection or drop them off at the local water park.
In some states, children with a single negative stool culture may attend child care but are excluded from interacting with other children. Such “cohorting” of convalescing children is better than excluding them entirely. This makes sense because data suggest that if the first convalescent stool culture is negative, the second one almost always is as well (Pediatr. Infect. Dis. J. 2010 May [doi:10.1097/INF.0b013e3181e4ee6e]). I would like to see a change in the regulations that would allow children to re-enter day care sooner.
Of course, it isn't surprising that day care attendance could facilitate transmission of Shigella. Ingestion of as few as 10 organisms is sufficient to produce infection. In a study a few years back, Dr. Andi Shane, a pediatric infectious disease specialist at Emory University, Atlanta, identified several risk factors for prolonged transmission in such settings, many of which are modifiable: soiled diapers accessible to children, water activities involving kiddie pools, volunteers who diapered infants, employed staff who had not received formal hand-washing education, hand-washing supplies that were kept out of the reach of children (and presumably the adults too!), and no adult supervision provided for hand washing in young children (Arch. Pediatr. Adolesc. Med. 2003;157:601–3).
The key to minimizing the transmission of shigellosis in day care centers is clear. Appropriate hand washing and diapering practices must be adhered to. This should include scheduled hand washing for everyone on arrival at the day care center, before meals, or after playing outdoors, along with supervised hand washing for young children. Banning kiddie pools could go a long way too but may not be a good idea on these hot summer days
Just to note: Shigellosis isn't exclusive to children. After our last day care outbreak, I alerted our community to the history related to the Rainbow Family Gathering, a national event orchestrated by a group promoting world peace. Poor sanitation coupled with common sources for food and water facilitated person-to-person spread and one of the largest outbreaks ever reported (J. Infect. Dis. 1990;162:1324–8).
As my community battles another large Shigella outbreak, I wanted to point out a few aspects of the infection that are often overlooked.
An estimated 450,000 cases of shigellosis occur every year in the United States, the majority among children who are not yet toilet trained. Here in the Kansas City area, we've had an ongoing Shigella sonnei outbreak since November 2009, with more than 250 cases diagnosed to date.
While the diarrhea is usually mild and self-limited, it is highly contagious through the fecal-oral route. Treatment is recommended for confirmed cases, both to stem transmission and to shorten disease duration. Of concern, resistance to trimethoprim-sulfamethoxazole has risen dramatically, from 47% in 1999–2003 to 89% in 2006. Ampicillin resistance also jumped, from 80% to 86%, while strains resistant to both drugs rose from 38% to 89% (MMWR 2006;55:1068–71).
However, azithromycin remains a good choice for treatment and is recommended in the Red Book as a potential treatment option for shigellosis. Dosing is 10 mg/kg one time on day 1 and then 5 mg/kg once a day for 4 more days (maximum 500 mg on day 1 and 250 mg thereafter). Microbiology labs do not routinely report azithromycin-susceptibility data, but randomly selected isolates have been tested during our current outbreak and thus far all are susceptible.
Most isolates are also susceptible to both ceftriaxone and ciprofloxacin, but both of those drugs are approximately five times more expensive than azithromycin is, and fluoroquinolones aren't approved for treating shigellosis in children younger than 18 years of age unless there are no other choices.
Some data also support the use of oral cephalosporins, but eradication rates are lower than with other drugs, so they currently are not recommended.
The last Shigella outbreak in Kansas City, in 2005, involved more than 400 cases over a period of 6 months and also featured a multidrug-resistant strain. Most children had mild disease, but we encountered an obstacle in that Missouri state law requires two negative stool cultures after treatment before the child can return to school or day care, which typically took 2–3 weeks to achieve. Appropriate treatment was often delayed because of empiric therapy with drugs to which strains were resistant and/or preauthorization requirements for using alternative drugs. Getting the families to come back for the repeat culture also was often a challenge.
There are few data to support exclusion policies that mandate two negative cultures. In contrast, some data suggest that such policies prolong the outbreak, in part because some parents will simply move their child to another day care center without mentioning the infection or drop them off at the local water park.
In some states, children with a single negative stool culture may attend child care but are excluded from interacting with other children. Such “cohorting” of convalescing children is better than excluding them entirely. This makes sense because data suggest that if the first convalescent stool culture is negative, the second one almost always is as well (Pediatr. Infect. Dis. J. 2010 May [doi:10.1097/INF.0b013e3181e4ee6e]). I would like to see a change in the regulations that would allow children to re-enter day care sooner.
Of course, it isn't surprising that day care attendance could facilitate transmission of Shigella. Ingestion of as few as 10 organisms is sufficient to produce infection. In a study a few years back, Dr. Andi Shane, a pediatric infectious disease specialist at Emory University, Atlanta, identified several risk factors for prolonged transmission in such settings, many of which are modifiable: soiled diapers accessible to children, water activities involving kiddie pools, volunteers who diapered infants, employed staff who had not received formal hand-washing education, hand-washing supplies that were kept out of the reach of children (and presumably the adults too!), and no adult supervision provided for hand washing in young children (Arch. Pediatr. Adolesc. Med. 2003;157:601–3).
The key to minimizing the transmission of shigellosis in day care centers is clear. Appropriate hand washing and diapering practices must be adhered to. This should include scheduled hand washing for everyone on arrival at the day care center, before meals, or after playing outdoors, along with supervised hand washing for young children. Banning kiddie pools could go a long way too but may not be a good idea on these hot summer days
Just to note: Shigellosis isn't exclusive to children. After our last day care outbreak, I alerted our community to the history related to the Rainbow Family Gathering, a national event orchestrated by a group promoting world peace. Poor sanitation coupled with common sources for food and water facilitated person-to-person spread and one of the largest outbreaks ever reported (J. Infect. Dis. 1990;162:1324–8).
As my community battles another large Shigella outbreak, I wanted to point out a few aspects of the infection that are often overlooked.
An estimated 450,000 cases of shigellosis occur every year in the United States, the majority among children who are not yet toilet trained. Here in the Kansas City area, we've had an ongoing Shigella sonnei outbreak since November 2009, with more than 250 cases diagnosed to date.
While the diarrhea is usually mild and self-limited, it is highly contagious through the fecal-oral route. Treatment is recommended for confirmed cases, both to stem transmission and to shorten disease duration. Of concern, resistance to trimethoprim-sulfamethoxazole has risen dramatically, from 47% in 1999–2003 to 89% in 2006. Ampicillin resistance also jumped, from 80% to 86%, while strains resistant to both drugs rose from 38% to 89% (MMWR 2006;55:1068–71).
However, azithromycin remains a good choice for treatment and is recommended in the Red Book as a potential treatment option for shigellosis. Dosing is 10 mg/kg one time on day 1 and then 5 mg/kg once a day for 4 more days (maximum 500 mg on day 1 and 250 mg thereafter). Microbiology labs do not routinely report azithromycin-susceptibility data, but randomly selected isolates have been tested during our current outbreak and thus far all are susceptible.
Most isolates are also susceptible to both ceftriaxone and ciprofloxacin, but both of those drugs are approximately five times more expensive than azithromycin is, and fluoroquinolones aren't approved for treating shigellosis in children younger than 18 years of age unless there are no other choices.
Some data also support the use of oral cephalosporins, but eradication rates are lower than with other drugs, so they currently are not recommended.
The last Shigella outbreak in Kansas City, in 2005, involved more than 400 cases over a period of 6 months and also featured a multidrug-resistant strain. Most children had mild disease, but we encountered an obstacle in that Missouri state law requires two negative stool cultures after treatment before the child can return to school or day care, which typically took 2–3 weeks to achieve. Appropriate treatment was often delayed because of empiric therapy with drugs to which strains were resistant and/or preauthorization requirements for using alternative drugs. Getting the families to come back for the repeat culture also was often a challenge.
There are few data to support exclusion policies that mandate two negative cultures. In contrast, some data suggest that such policies prolong the outbreak, in part because some parents will simply move their child to another day care center without mentioning the infection or drop them off at the local water park.
In some states, children with a single negative stool culture may attend child care but are excluded from interacting with other children. Such “cohorting” of convalescing children is better than excluding them entirely. This makes sense because data suggest that if the first convalescent stool culture is negative, the second one almost always is as well (Pediatr. Infect. Dis. J. 2010 May [doi:10.1097/INF.0b013e3181e4ee6e]). I would like to see a change in the regulations that would allow children to re-enter day care sooner.
Of course, it isn't surprising that day care attendance could facilitate transmission of Shigella. Ingestion of as few as 10 organisms is sufficient to produce infection. In a study a few years back, Dr. Andi Shane, a pediatric infectious disease specialist at Emory University, Atlanta, identified several risk factors for prolonged transmission in such settings, many of which are modifiable: soiled diapers accessible to children, water activities involving kiddie pools, volunteers who diapered infants, employed staff who had not received formal hand-washing education, hand-washing supplies that were kept out of the reach of children (and presumably the adults too!), and no adult supervision provided for hand washing in young children (Arch. Pediatr. Adolesc. Med. 2003;157:601–3).
The key to minimizing the transmission of shigellosis in day care centers is clear. Appropriate hand washing and diapering practices must be adhered to. This should include scheduled hand washing for everyone on arrival at the day care center, before meals, or after playing outdoors, along with supervised hand washing for young children. Banning kiddie pools could go a long way too but may not be a good idea on these hot summer days
Just to note: Shigellosis isn't exclusive to children. After our last day care outbreak, I alerted our community to the history related to the Rainbow Family Gathering, a national event orchestrated by a group promoting world peace. Poor sanitation coupled with common sources for food and water facilitated person-to-person spread and one of the largest outbreaks ever reported (J. Infect. Dis. 1990;162:1324–8).