Minnesota Department of Health (MDH) Bug Bytes
June 24, 2002
Vol. 3: No. 8
1. Group A Streptococcus Cluster
Last week a case of invasive group A Streptococcus (GAS) was reported in a nursing home resident. This was the third invasive case reported in residents from the home; two other cases had been seen in March and April. All 3 case-patients had positive blood cultures and all three survived. Isolates from all 3 matched by PFGE molecular subtyping, all having the most common subtype seen in Minnesota.
Clusters of invasive GAS in nursing homes have been reported before in the medical literature and we have experienced them twice before in Minnesota in the recent past. GAS may be introduced into a nursing home by symptomatic or asymptomatic residents, staff, or visitors. Prevention is important in this vulnerable elderly population. Strict adherence to good infection control techniques including handwashing and glove use have proven useful. Our investigation is in progress. We obtained throat cultures of all residents and staff. Those who have positive cultures will be treated with antibiotics (penicillin and rifampin, or clindamycin or azithromycin) to eliminate carriage.
Two weeks ago a 59 year-old female patient was seen in an ER for evaluation of diffuse myalgia, fever (101° F), nausea, vomiting, headache, and a swollen right ankle. The patient reported being bitten on the finger by her pet rat 10 days previously. The bite wound was small and resolved without treatment.
The patient's CBC showed an increase in immature neutrophils with a low normal total leukocyte count. Her hemoglobin and platelet count were in the low normal range. No other blood abnormalities were seen. A joint tap was performed on the swollen ankle and revealed leukocytosis. A bacterial culture of the joint fluid confirmed the presence of Streptobacillus moniliformis, the causative agent of rat-bite fever.
S. moniliformis is a facultative anaerobic, Gram-negative bacillus. The organism is carried in the nasopharynx of an estimated 50-100% of wild and laboratory rats. Rat-bite fever is a systemic bacterial infection with either S. moniliformis or rarely Spirillum minus. The bacteria are usually introduced via a bite wound, but transmission has occurred by ingestion of food and water contaminated with rodent feces (known as Haverhill fever, named after an outbreak in 1926 in Haverhill, Massachusetts associated with raw milk). Once infection occurs, the bacteria spread systemically and often settle in the joints. The most common clinical signs include chills, headache, relapsing fever, asymmetric polyarthritis, maculopapular rash on the soles and palms, progressive myalgia, nausea, and vomiting. Clinical signs typically occur 2-10 days after the exposure. Diagnosis is made by isolation of the organism from blood or joint fluid. Clinical signs may resolve without treatment, but relapses can occur. The recommended treatment is IV penicillin for 5-7 days followed by 7 days of oral penicillin. The case fatality rate for untreated cases is 5-15%. Mild cases can be treated with oral penicillin alone.
We are investigating an outbreak of Campylobacter infections among volunteer relief workers assisting with flood clean-up efforts in Roseau. Eight of 24 workers who were picking up dead turkeys (reported to number 10,000) and placing them in piles for insurance reimbursement purposes developed fever, chills, abdominal pain, and severe diarrhea 2-3 days after handling the turkey carcasses. Two case-patients had Campylobacter isolated from stool; identification to species is pending in our lab. Illness was associated with fetching fowl/touching turkeys/piling poultry and not washing hands or merely rinsing hands in a communal water bucket as compared to dead turkey exposure and kitchen sink soap-and-water handwashing.
Bat bites constitute a risk for rabies and necessitate rabies postexposure prophylaxis (PEP)(if the bat cannot be tested and shown to be negative for rabies). You might recall that we had a case of human rabies in 2000 due to a bat bite. Unfortunately, we received a not too uncommon call this week from a person who suffered a bat bite on her finger, and who was sent home and told by her clinician to "watch for swelling". Thankfully, she checked with us and is now undergoing PEP. PEP is also recommended in situations in which a bat bite cannot be ruled out, such as when a bat is found in a room with a previously unattended child, or a person wakes up to find a bat in the same room. Our telephone (651-201-5414 or 1-877-676-5414) is manned 24 hours a day to provide recommendations for rabies prophylaxis.
5. Erratum: Reporting Hepatitis
To clarify an article in the last Bug Bytes issue, while the hepatitis C database was established at MDH in 1998, data collection has been ongoing since the early 1990s. Both chronic and acute hepatitis C infections have been reportable in Minnesota since the early 1990s and continue to be.
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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