Suspected Nosocomial Influenza Cases in an Intensive Care Unit
Georgia. During November 1987, CDC received reports of three
patients and one nurse with suspected influenza infections in a
15-bed
medical-surgical intensive care unit (MSICU). The index case
occurred
in a 71-year-old female with diabetes mellitus who was admitted to
the
MSICU on October 29 and subsequently required mechanical
ventilation.
Influenza A was identified by fluorescent antibody (FA) staining of
tissue culture cells inoculated with an endotracheal aspirate
collected on November 11. The patient died on November 14, and
influenza virus was identified in lung tissue collected postmortem.
The second patient, an intubated 60-year-old woman with chronic
obstructive lung disease, had been hospitalized since October 26.
Influenza A was identified by FA staining of cell culture
inoculation
of a lung biopsy specimen obtained on November 23. The same
procedure
was used to identify influenza A in an endotracheal aspirate
specimen
collected on November 26 from an intubated 76-year-old man who had
been hospitalized since September 28. Further investigation
revealed
that a nurse who had cared for all three patients was absent from
work
during the last week of November because of an influenza-like
illness.
Neither the three patients nor the nurse had received the 1987-88
influenza vaccine. Isolates were not available for confirmation and
subtype identification.
Other reports. For the report week ending January 2, four
states*
reported regional outbreaks of influenza-like illness. Fifteen
states** have reported isolates of influenza A(H3N2), which is the
predominant subtype so far this season. Influenza A, subtype
pending,
has been reported from Hawaii, Louisiana, Utah, and Washington.
Reported by: P Patterson, D Smith, RK Sikes, DVM, MPH, State
Epidemiologist, Georgia Dept of Human Resources. Univ Hygienic
Laboratory, Univ of Iowa. Participating State and Territorial
Epidemiologists and State Laboratory Directors. WHO Collaborating
Center for Influenza, Influenza Br, Div of Viral Diseases, Center
for
Infectious Diseases, CDC.
Editorial Note
Editorial Note: In the past, hospital laboratories have had to
send
specimens to reference laboratories for virus isolation and
identification. Now, many hospital laboratories are able to rapidly
identify influenza A or B viruses by using monoclonal antibodies
for
typing virus antigens produced in cell culture. Results can usually
be
obtained within 24 to 72 hours after inoculation of the specimen.
Rapid diagnosis may be particularly useful in preventing
nosocomial outbreaks of influenza A since patients exposed to the
virus can be given amantadine, an antiviral drug effective against
influenza type A. Rapid diagnostic capabilities may also help
hospitals encourage their staffs to use antiviral prophylaxis or to
be
vaccinated, as recommended by the Immunization Practices Advisory
Committee (ACIP) (1). Rapid diagnosis, coupled with prompt
reporting
to public health officials, will also help detect possible
epidemics.
However, confirmation by a second laboratory is important during
nonepidemic periods because it will help avoid reports of
false-positive results, which could set control measures into
motion
unnecessarily.
The cases reported here were identified by laboratory testing.
Ideally, suspect isolates should be saved, and a sample should be
forwarded to the appropriate state health department for
confirmation.
Isolates confirmed by state health departments are then forwarded
to
the WHO Collaborating Center for Influenza at CDC for detailed
antigenic analysis, including strain identification. Early in the
influenza season, these antigenic analyses need to be performed on
as
many isolates as possible because the findings are used to identify
vaccine strains for the coming year.
Reference
Immunization Practices Advisory Committee. Prevention and
control
of influenza. MMWR 1987;36:373-80,385-7.
*Alabama, South Dakota, Utah, and Wisconsin.
**California, Colorado, Florida, Iowa, Kansas, Minnesota, Missouri,
Montana, North Dakota, South Carolina, South Dakota, Tennessee,
Texas,
Wisconsin, and Wyoming.
Disclaimer
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