Minnesota Department of Health (MDH) Bug Bytes
July 24, 2001
Vol. 2: No. 14
1. Nursing Home Respiratory Disease Outbreak -- In the Summer?
2. Salmonella Enteritidis Outbreak
3. Group B Streptococcus Awareness Month
4. Malaria Fatality Update and Other Mosquito-Borne Diseases
5. Dog Days of Summer
1. Nursing Home Respiratory Disease Outbreak -- In the
Summer?
Respiratory disease outbreaks in nursing homes in summer months are unusual.
In the first week of July an ICP at a 60-bed nursing home called us for
advice (kudos to her; we are from the government and we are here to help).
In late June and early July six residents developed severe respiratory
disease or pneumonia. One resident who had pneumonia died; the cause of
his pneumonia was not determined and cultures were negative. Two other
residents had Streptococcus pneumoniae isolated by blood culture.
Both isolates were received at MDH where antimicrobial sensitivity testing,
serotyping, and PFGE were performed. Both were identically multiple drug-resistant,
serotype 14 (a strain found in the adult pneumococcal vaccine), and had
the same PFGE subtype. Thus, this gave further evidence to our suspicion
that this was an outbreak of pneumococcal disease, itself an uncommon
event. To prevent additional cases, isolation precautions were initiated
at the home, and all residents meeting ACIP criteria for pneumococcal
vaccination (i.e. 65 years of age and older or with underlying chronic
conditions; guidelines at http://www.cdc.gov/mmwr/PDF/RR/
RR4608.pdf Attention: Non-MDH link) were
vaccinated. S. pneumoniae is the most common cause of nursing home-acquired
pneumonia. The emergence of S. pneumoniae antimicrobial resistance
underscores the need for vaccination, particularly among the elderly in
nursing homes.
2. Salmonella Enteritidis Outbreak
Timely interventions in outbreak situations are dependent on a well
functioning surveillance system. Once again, thanks to ICPs and
microbiology laboratory directors, we were alerted to an outbreak
of Salmonella Enteritidis (SE) associated with a busy restaurant.
On July 13 (these events always occur on a Friday afternoon), we
became aware of nine isolates of SE, three with the same PFGE subtype,
which had been submitted to our laboratory. Working over the weekend,
we determined that seven of these cases had eaten a meal at a specific
restaurant located off I-90 in southern Minnesota prior to their
illness. All of the cases lived in Faribault or Martin County. Since
then there have been an additional five cases including two from
South Dakota. Most cases reported eating an egg dish. Illness onsets
ranged from June 25 to July 9. All had diarrhea and fever; four
were hospitalized. The restaurant was inspected and all workers
were interviewed on July 16. Stool samples were collected from all
employees; to date, 1/53 is positive for SE. Ill workers and those
positive for SE are excluded from food handling until they have
two stools submitted at least 24 hours apart, both of which test
negative for Salmonella. The restaurant temporarily closed
and was thoroughly cleaned. Due to the location and high volume
nature of the restaurant, it's likely there are ill patrons dispersed
throughout the U.S. It's the timely reporting and submission of
isolates that allowed us to intervene and prevent ongoing disease
transmission. We suspect eggs to be the original source of SE with
ongoing transmission possibly sustained from infected foodhandlers.
3. Group B Streptococcus Awareness Month
July is Group B Streptococcus (GBS) Awareness Month! We tend to get excited
by these events. GBS is the leading cause of invasive bacterial infection
in newborns. In May 1996, the CDC, the American College of Obstetricians
and Gynecologists, and the American Academy of Pediatrics published guidelines
which urged providers to take either a screening-based or risk-based approach
to determine use of intrapartum antibiotic prophylaxis (IAP) for the prevention
of perinatal GBS disease (at http://wonder.cdc.gov/wonder/prevguid/
m0043277/m0043277.asp Attention: Non-MDH link).
If a screening-based approach is used, vaginal/rectal cultures should
be obtained at 35-37 weeks gestation and cultured using a selective broth
medium. In Minnesota there were 1,082 cases of invasive GBS disease reported
from 1997-2000; 825 (76%) were non-maternal adults, 120 (11%) early-onset
[EO; 0-6 days of age], 79 (7%) late-onset [7-89 days of age], 54 (5%)
maternal, and 4 (<1%) cases were among children 90 days to 14 years of
age. We reviewed charts of the 120 women who had infants with EO GBS disease
during 1997-2000 (34 in 1997, 28 in 1998, 25 in 1999, and 33 in 2000).
Four (3%) infants died. Bacteremia without focus (80%) was the most common
type of infection reported, followed by pneumonia (14%), and meningitis
(5%). Thirty-three (28%) of these 120 women were prenatally screened for
GBS; 12 were positive (and 7 of these women received IAP), 19 were GBS
negative, and 2 had unknown results. Among women who were GBS negative,
up to 89% may have been screened inappropriately with either documentation
of the wrong site or wrong time in gestation, or no documentation of site
and time. Twenty-seven (23%) of these 120 women had at least one documented
GBS risk factor (gestation < 37 weeks - 20; intrapartum fever - 7; rupture
of membranes at >18 hours - 7; GBS bacteriuria - 5). Overall,
18 (15%) of the 120 women received IAP. Only 15 (48%) of 31 women who
had a positive screen or were screened and had at least one GBS risk factor
received IAP (50% in 1997, 33% in 1998, 50% in 1999, and 55% in 2000).
Providers are urged to review the prevention guidelines and ensure that
the mechanisms are in place to ensure access to results of GBS screens
and timely delivery of IAP. Laboratories should ensure that the appropriate
procedures are done on GBS screens. A laboratory protocol on the isolation
of GBS from screening cultures can be found on the MDH Group
B Strep website. The IAP guidelines will be reviewed this fall in
a working group at CDC; we will keep you informed.
4. Malaria Fatality Update and Other Mosquito-Borne Diseases
In the April 3, 2001 edition of Bug Bytes (archived on the MDH website
[see below]), we discussed a malaria fatality in a Minnesota resident.
This case and others are reported in last week's MMWR (at http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5028a1.htm).
Due to an adverse reaction to mefloquine (the recommended malaria prophylaxis
for chloroquine-resistant malaria areas in Africa) during a prior trip,
the patient used a combination of chloroquine and Paludrine (proguanil;
not available in the U.S.) as prophylaxis. While these drugs are commonly
used by Europeans visiting Africa, the efficacy of the combination is
thought to be declining. It also appears that the patient discontinued
prophylaxis shortly after returning from Africa. The cases described in
the MMWR article underscore the importance of including malaria
in the differential diagnosis for febrile patients with a history of travel
to malaria-endemic parts of the world. In addition, people traveling to
these areas should use the recommended prophylaxis, and be reminded to
be compliant with the dosing schedule. Since November 2000, the CDC has
recommended mefloquine, doxycycline, or Malarone for chemoprophylaxis in
areas with chloroquine-resistant malaria. Speaking of mosquito-borne disease,
we are currently entering the high-risk period for LaCrosse encephalitis
and other arboviruses in Minnesota. If you suspect you have a case of
arboviral encephalitis in a patient, please call us at (612) 676-5414
and submit serum and CSF (if available) to our laboratory.
5. Dog Days of Summer
These are the Dog Days of Summer (mid-July to September). Be careful.
According to the "Husbandman's Practice (1729), " …the heat of the
sun is so fervent and violent that men's bodies at midnight sweat
as at midday; and if they be hurt, they be more sick than at any
other time - yea very near dead."
Bug Bytes is a combined effort of the Infectious Disease Epidemiology, Prevention and Control Division and the Public Health Laboratory Division of MDH. We provide Bug Bytes as a way to say THANK YOU to the infection control professionals, laboratorians, local public health professionals, and health care providers who assist us.
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