Minnesota Department of Health (MDH) Bug Bytes

March 19, 2002
Vol. 3: No. 5


Topics in this Issue:

1. Group B Streptococcus Trends
2. Community-onset Methicillin Resistant Staphylococcus aureus
3. Heavy Bather Load and Illness
4. Knee Surgery Update
5. Diphtheria Testing
6. Happy Birthday, John Snow

Several of us will be attending next week's International Conference on Emerging Infectious Diseases in Atlanta. We will highlight some of the work we have been doing with your help. Your efforts have tremendous public health implications. Thank you!

1. Group B Streptococcus Trends
While the incidence of perinatal early-onset group B Streptococcus has declined, it still is a major cause of neonatal morbidity and mortality (22 early-onset cases including 3 deaths in 2001 in Minnesota). Intrapartum antimicrobial prophylaxis (IAP) is recommended to prevent early-onset disease using either a screening or risk-based approach to determine which mothers need prophylaxis. Consensus guidelines issued in 1996 (at http://www.cdc.gov/mmwr/preview/
mmwrhtml/00043277.htm
) recommend that penicillin with ampicillin as an alternative be used for IAP; and clindamycin or erythromycin in cases of penicillin allergy. To determine trends in antimicrobial susceptibility, and identify serotype and serotype resistant trends to guide development of a vaccine, we analyzed data from Minnesota and three other Emerging Infection Program sites (NY, GA, and OR) for 1996-2000. These data will be presented at next week's conference.

No isolates were resistant to penicillin, ampicillin, cephalothin/cefazolin, or vancomycin. Clindamycin resistance was found in 11% and erythromycin resistance in 19% of isolates. Clindamycin resistance and erythromycin resistance were associated with serotype V, an emerging serotype. Other studies have also found clindamycin and erythromycin resistance in GBS. The 2000 Red Book does include cefazolin as an option for IAP for women with a penicillin allergy who are able to tolerate cephalosporins. The consensus guidelines are currently undergoing revision and will address this issue.

2. Community-onset Methicillin Resistant Staphylococcus aureus
Community-onset methicillin resistant Staphylococcus aureus (CO-MRSA) was recognized as an emerging pathogen in Minnesota and elsewhere a few years ago. To better understand its epidemiology, we instituted a sentinel surveillance system in 2000 in 12 hospital laboratories (thank you ICPs and labs!). We compared traditional healthcare-associated MRSA (HA-MRSA) to CO-MRSA in 2000.

CO-MRSA patients tended to be younger and more likely to have MRSA isolated from their skin than HA-MRSA patients. We conducted PFGE molecular subtyping on isolates and found that CO-MRSA isolates were more likely to be from one distinctly different clonal group than HA-MRSA isolates. CO-MRSA isolates were more likely than HA-MRSA to be susceptible to ciprofloxacin, clindamycin, trimethoprim/sulfamethoxazole, gentamicin, and erythromycin. However, only 44% of CO-MRSA isolates and 8% of HA-MRSA isolates were susceptible to erythromycin. Although CO-MRSA isolates are resistant to beta-lactam antimicrobials, these agents were commonly used as empiric therapy.

We will continue our surveillance for CO-MRSA and begin to examine risk factors for infections. These data will also be presented at next week's conference.

3. Heavy Bather Load and Illness
Two weeks ago we were notified of gastrointestinal illness and rash among players of three youth hockey teams that had attended an overnight tournament in north central Minnesota. The players and their families stayed at a local hotel and had used the pool and hot tub extensively. Potlucks were held by separate teams (and a hot dog eating contest at the hockey arena [the winning team ate >120!]); many had eaten a common breakfast at the hotel. Eighty persons were interviewed; 11 developed a rash. No one saw a physician and our information about the rash is not detailed, but most developed a rash more than 12 hours after bathing. Illness was associated with use of the pool. In addition, 36 (45%) reported vomiting and/or diarrhea. The majority of those ill were youth and illness was associated with use of the pool or hot tub. One stool sample was submitted to us; it was negative for bacterial pathogens and positive for calicivirus by PCR . We received anecdotal reports that the pool/hot tub were crowded and dirty.

Environmental health specialists inspected the pool facility and found several deficiencies. Although not laboratory-confirmed, Pseudomonas aeruginosa is suspected as the cause of the rash. Norwalk-like virus (i.e. calicivirus) was the cause of gastrointestinal illness and likely transmitted through the contaminated pool and hot tub.

4. Knee Surgery Update
In last week's MMWR (at http://www.cdc.gov/mmwr/mmwr_wk.html) was an article updating the national investigation of allograft-associated infections that followed our report of a death due to Clostridium sordellii in a 23-year old following knee surgery and receipt of a tissue allograft. Since our report, CDC received and investigated an additional 25 bacterial infections associated with musculoskeletal tissue allografts. Thirteen (including our case) were infected with Clostridium spp., 11 with gram-negative bacilli, and two had negative cultures (but evidence of infection). Fourteen infections were from tissue that was from the same tissue bank that was the source of infection for our patient.

Current regulations and industry guidelines for the procurement, processing, and testing of tissue allografts need revision in order to protect patients. Unless a sporicidal method is used, aseptically processed tissue should not be considered sterile, and health-care providers should be informed of the possible risk for bacterial infection. We continue to welcome reports of suspect post-allograft infections.

5. Diphtheria Testing
Diphtheria is an uncommon disease in the U.S.; the last reported case in Minnesota occurred in 1990. However, the disease is endemic in some developing countries, and epidemics have recently occurred in the former Soviet Union. Although there haven't been any cases recently in Minnesota, there are regular concerns about diphtheria due to the similar presentation of a number of less serious illnesses.

Suspect diphtheria cases, including all patients for whom diphtheria testing is performed as part of the differential diagnosis, should be reported to us immediately. If the case is strongly suspect, antitoxin should be administered without awaiting culture results. MDH staff can arrange for the authorized release of antitoxin from CDC. Antimicrobial therapy is not a substitute for antitoxin.

For laboratory diagnosis, a diphtheria kit is available from our laboratory, which consists of two Loeffler's slants labeled "Throat" and "Nose". Slants should be inoculated by streaking a swab of the respective sites onto the media (do not stab), leaving the swabs on the media. If slants cannot be delivered immediately to us, they should be incubated overnight at 37oC in ambient air and delivered the next day. When received by us, slants are observed at 18-24 hours, and 36-48 hours. If growth occurs, smears are made and stained using methylene blue stain. If the characteristic morphology for C. diphtheriae is demonstrated, the organism is further characterized by biochemical and molecular methods. If sending an inoculated kit, call the Special Microbiology Laboratory at 612-676-5253, so that we are aware a specimen is coming. If any laboratory needs to obtain diphtheria media kits to have on hand, please call 612-676-5396 to order them.

6. Happy Birthday, John Snow
On March 15, 1813 John Snow was the first of 9 children borne to a poor laborer in York, England. Despite his humble beginnings he became a physician and a researcher who published 82 articles. Not long after its discovery, he administered chloroform to Queen Victoria on two occasions for labor and delivery. Most importantly, he is considered one of the founders of modern epidemiology. In 1849, he published On the Mode of Communication of Cholera, in which he concluded that cholera was caused by an infectious microorganism, even though the causative agent had not yet been isolated. He is most beloved by public health professionals for his advice given on September 7, 1854 to remove the pump handle from the Broad Street pump, thereby ending the cholera outbreak in the area. Through meticulous epidemiological sleuthing, he determined the pump water was contaminated by sewage and was the source of illness.

 

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, 19-Nov-2010 14:16:50 CST