State Health Commissioner Provides Update on State/County Investigation of Invasive Group A Streptococcus Cases in Rochester Region

Rochester, March 14 – State Health Commissioner Barbara A. DeBuono, M.D., announced today that an investigation of invasive Group A streptococcus infections in Monroe and surrounding counties has not identified any evidence of a community outbreak involving a common source of infection or a significantly higher than expected number of cases occurring in the region this year.

The investigation was initiated by the New York State and Monroe County Departments of Health following reports of three cases of Group A streptococcus in an obstetric unit at Strong Memorial Hospital.

"Based on our findings to date I can assure residents of this area that they are at no increased risk for invasive Group A streptococcus infection, and should not fear going to Strong Memorial Hospital or any other hospital in the region for needed medical care," Commissioner DeBuono said.

The joint State–County multi–county investigation involved identification of all confirmed cases of invasive Group A streptococcus occurring in Monroe and six surrounding counties (Orleans, Genesee, Livingston, Ontario, Wayne, Yates) since the beginning of 1997. Case reports were reviewed to determine if there was any apparent common exposure among the cases, and if the number of cases occurring in this time period was higher than expected for the population. Health Department disease control physicians and epidemiologists also conducted an on site investigation of three cases identified by Strong Memorial Hospital in their obstetrical unit in February. Streptococcal cultures from these cases have been tested at the State Health Department's Wadsworth Center.

Number of Cases in 1997 Not Higher Than Expected

"While the 22 cases reported so far in 1997 from Monroe County and surrounding counties is somewhat higher than in the same time period in 1996, the numbers are well within the expected rate for this disease," Dr. DeBuono said.

"We believe the increased number of cases reported so far this year may be a result of more complete reporting by hospitals and laboratories in the region. Invasive Group A streptococcus was made a reportable disease in New York State in May 1995, and we have seen increasing statewide compliance with this regulation over the past year."

Incidence rates of invasive Group A streptococcal infections in other parts of the United States vary, ranging from a low of 1.5 cases per 100,000 population to a high of 8 cases per 100,000 population. Using these rates, we would expect between 17 and 88 cases of invasive Group A strep each year in the Rochester Metropolitan Service Area. The estimated average incidence rate of invasive Group A streptococcal is approximately 5 cases per 100,000 population, which would translate into 55 cases a year in the region.

Since January 1997, a total of 17 cases of invasive Group A streptococcus infection have been confirmed in Monroe County, compared with 12 cases during the same period last year. Five cases have been confirmed in surrounding counties (Livingston – 1; Ontario –3; Orleans – 1) compared to one case in Orleans last year. One additional suspect case (in Livingston) is being investigated.

"Late winter and early Spring are the peak times for streptococcal infections," Dr. DeBuono pointed out. In 1996, 32 percent of cases statewide were reported during the months of January through March.

Five of the 22 patients (23 percent) diagnosed with invasive Group A streptococcus in 1997 in the Rochester area have died as a result of the infection. This death rate is comparable to rates from across the nation.

No Common Community Exposure Identified

Review of all 1997 case reports from Monroe and surrounding counties did not reveal any common link among the individuals, with the exception of the three cases that occurred among patients on the obstetrical unit at Strong Memorial Hospital. Virtually all other cases occurred in the community, in 15 different cities, and were not linked with the maternity cases at Strong Memorial.

Strong Memorial Obstetrical Unit Investigation

Three cases of Group A streptococcus occurred among patients who delivered babies at Strong Memorial between February 16 and 20. One of the patients developed necrotizing fasciitis and died despite treatment. The other two patients received treatment and have been discharged from the hospital.

Strong Memorial Hospital acted swiftly and appropriately as soon as cases of invasive Group A streptococcus infection were identified in the obstetrical unit. The hospital immediately reported the cases to the State Health Department as required by State regulation.

Visitors to the obstetrical services were restricted, and all staff who provided any care to the infected patients were identified and tested for Group A streptococcus. Any workers who had positive throat cultures were excluded from work in the hospital until they were treated.

One health care worker who cared for two of the three infected patients at Strong Memorial had a positive throat culture for Group A streptococcus infection, but showed no symptoms of strep throat while caring for the patients. Another worker, who cared for the third infected patient and also had no symptoms at the time of providing patient care, was subsequently diagnosed with Group A streptococcus on February 22.

Streptococcal cultures from the infected maternity patients and health care workers in the maternity unit at Strong Memorial have been tested at the State Health Department's Wadsworth Center using a type of DNA–fingerprinting called pulsed–field gel electrophoresis. Results showed that the Group A streptococcus strains from the three patients and two maternity unit health care workers are indistinguishable by this testing method, and they are different from strains tested from patients admitted to other parts of the hospital. Based on previous testing of streptococcal cultures statewide and from the Rochester area, the identified strain appears to be an uncommon one. Control measures have been taken by the hospital and there have been no new cases identified at the hospital in the past two weeks.

"It is recognized that patients undergoing surgery or hospitalized with a serious medical problem can be at increased risk for all types of infections," the Commissioner said. "For this reason hospitals are required to have very stringent infection control procedures to minimize potential infections. But, even when infection control practices are scrupulously followed, occasional in–hospital infections occur."

Public Health Recommendations

"Although infection with invasive Group A streptococcus is a serious health problem, the public should not be unnecessarily alarmed," Dr. DeBuono said. "There are steps the public and physicians can take to minimize the risk and to diagnose and successfully treat the infection when it occurs."

  • Prompt identification and treatment of Group A strep infections is the most important strategy to decrease the risk of serious complications from infection and to reduce the spread of disease to other persons.
  • Persons with symptoms of strep throat ( sore throat, fever, swollen lymph nodes) should see their doctor.
  • A throat culture is the test of choice for persons with strep throat. There are concerns that "rapid streptococcal tests" may not detect Group A streptococcal pharyngitis as well as throat cultures. Therefore, when a person suspected of having Group A strep has a negative rapid streptococcal test, a throat culture should be obtained to completely rule out the disease.
  • Penicillin for at least 10 days is the drug of choice to treat strep throat. Erythromycin can be used for patients who are allergic to penicillin.
  • A follow–up throat culture after treatment is usually indicated only in patients who are at high risk of rheumatic fever or who still have symptoms.
  • Children should not return to school or child care until they have completed at least 24 hours of antibiotic treatment and do not have a fever.

3/14/97–28 OPA