LAC DPH Health Alert: Cluster of Shigella flexneri Infections among Men in Los Angeles

LAC DPH Health Alert [pdf]

 Cluster of Shigella flexneri Infections among Men in Los Angeles

shig

Key Messages

  • Between May and August 2016, a cluster of Shigella flexneri cases occurred among adult men, predominantly men who have sex with men (MSM), in Los Angeles and other Southern California counties.
  • Health care providers should obtain cultures from persons with fever and bloody diarrhea for diagnosis, particularly from persons at increased risk.

Health care providers should educate patients to reduce risk of transmission of Shigella to others. For MSM, changing sexual behaviors can be important.

 

Situation

On August 8, 2016, the California Department of Public Health (CDPH) notified the Los Angeles County Department of Public Health (LAC DPH) of a cluster of nine Shigella flexneri cases, with an uncommon strain, serotype 7 (also known as 1c or provisional 88-893), from LAC, Pasadena, Long Beach and nearby counties.  Three were known to require hospitalization and one patient, an LAC resident, died.  All patients were men.  Ages ranged between 28 and 57 years old (median, 32 years old).  Four self-identified as gay or bisexual and four are immunocompromised. Common symptoms include fever, diarrhea, and abdominal pain; four of six patients for whom data were available indicated that the diarrhea was bloody. No patients provided a history of recent domestic or international travel.  Three strains tested for antimicrobial susceptibility showed resistance to ampicillin and trimethoprim/sulfamethoxazole (Bactrim, Septra).  Since August 19, an additional four cases were reported with infection caused by the same S. flexneri serotype; further demographic and clinical data are pending.  No other S. flexneri, serotype 7 isolate has been identified from LAC since 2014.

A total of 49 and 48 cases of S. flexneri were reported to LAC DPH through August 2015 and 2016, respectively.  Eighty-eight percent of the cases in both years were men. Shigella is most often spread person-to-person or by eating food contaminated by someone who is infected. Transmission is fecal-oral; MSM are known to be at increased risk

 

Actions Requested of Providers

√ Obtain a stool culture from MSM who present with fever and diarrhea, particularly if the diarrhea is bloody.

√ Consider obtaining a PCR test, if available for Shigella, in addition to culture as results may be available sooner facilitating therapy; PCR does not replace culture as an isolate is needed for serotyping and antimicrobial susceptibility testing.

√ Treat Shigella infection among MSM to shorten the duration of illness and to reduce shedding and the risk of transmission.  Empiric therapy may be warranted among MSM with bloody diarrhea and more severe illness, or those who are immunocompromised, pending culture and susceptibility results.  Isolates from this cluster and most Shigella are susceptible to ciprofloxacin.

√ Advise MSM to avoid sex for at least two weeks after recovery from illness.  When having sex again, MSM should refrain from oral-anal contact or use barriers such as condoms or dental dams.  Washing genitals, anus and hands before and after sexual activity also may reduce risk.

 

Reporting for Clinically Suspect Cases

Los Angeles County DPH Acute Communicable Disease Control Program:

Long Beach Health and Human Services:

  • Weekdays 8:00 am to 5:00 pm call the Epidemiology Program at 562-570-4302, or fax CMR to 562-570-4374.

Pasadena Public Health Department:

Communicable Disease Control Program 626-744-6089

 

For Questions about Shigella among MSM

Los Angeles County DPH Acute Communicable Disease Control Program:

  • Weekdays 8:30 am to 5:00 pm call 213-240-7941

Long Beach Health and Human Services:

  • Weekdays 8:00 am to 5:00 pm call 562-570-4302

Pasadena Public Health Department:

Communicable Disease Control Program 626-744-6089

 

Additional Resources on Shigella Infection

  • CDC webpages:

CDC, NIH, and Infectious Disease Society of America – guidance on management of Shigella among persons with HIV infection: https://aidsinfo.nih.gov/guidelines/html/4/adult-and-adolescent-oi-prevention-and-treatment-guidelines/328/bacterial-enteric

 

This Health Alert was sent by Dr. Benjamin Schwartz, Acting Chief, Acute Communicable Disease Control Program, Los Angeles County Department of Public Health.  

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