Minnesota Department of Health (MDH) Bug Bytes

July 24, 2001
Vol. 2: No. 14


Topics in this Issue:

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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Updated Friday, November 19, 2010 at 02:16PM