Yesterday, the Centers for Disease Control and Prevention (CDC) issued an update on the E. coli O145 outbreak linked to Freshway Foods romaine lettuce.

As of May 11, 2010, there are 23 confirmed and 7 probable cases related to this outbreak from Michigan, New York, Ohio, and Tennessee. The number of ill persons identified in each state with this strain is: Michigan (10 confirmed and 3 probable), New York (4 confirmed and 3 probable), Ohio (8 confirmed and 1 probable), and Tennessee (1 confirmed).  

To diagram the outbreak trend, the CDC has created an epidemic curve, or a chart that describes the number of persons that became ill each day.

Among the confirmed and probable cases with reported dates available, illnesses began between April 10, 2010 and April 26, 2010. Infected individuals range in age from 13 years old to 31 years old and the median age is 19 years. Sixty-six percent of patients are male.

Health investigators in New York recently obtained an E. coli O145 isolate from an unopened bag of romaine lettuce that matches the outbreak strain.
 
A separate case-control study in Michigan supported this, finding a significant association between illness and consumption of romaine lettuce from the same processing facility, which is believed to be located in Yuma, AZ.

The CDC said that investigators are using pulsed-field gel electrophoresis (PFGE), a type of DNA fingerprint analysis of E. coli bacteria obtained through diagnostic testing to identify cases of illness that might be part of this outbreak. This testing is done in public health laboratories as part of the PulseNet network. Investigators have established a common definition of confirmed and probable cases related to this outbreak.

An Ohio resident filed an E. coli lawsuit against Freshway Foods on Tuesday.