Minnesota Department of Health (MDH) Bug Bytes
March 23, 2009
Vol. 10: No.2
Three weeks ago we announced the first time a Klebsiella pneumoniae carbapenemase producer (more broadly referred to as carbapenem-resistant Enterobacteriaceae) was identified in Minnesota.
With the emergence of extended-spectrum beta-lactamase (ESBL) producing bacteria, clinicians have relied on carbapenems as the mainstay for treating infections due to these resistant Gram-negative organisms. With few treatment options available, infections from carbapenem-resistant Enterobacteriaceae (CRE) result in a mortality rate that is 4-times higher compared to infections with the same bacteria without this resistance. Additionally, treatment failures have been documented, since CRE expressing very low levels of resistance (MIC to carpabenems of 2 or 4µg/ml considered "susceptible" by current CLSI standards) make identification of these strains more difficult.
The most common type of genes coding for CRE resistance is the Klebseilla pneumoniae carbapenemase or KPC. These genes are carried on plasmids, allowing resistance to be readily disseminated within and between species of Enterobacteriaceae, including E. coli, S. marcescens, K. oxytoca, and Enterobacter spp. CRE and in particular KPC-containing K. pneumoniae are responsible for several outbreaks in the eastern United States and other countries since 2001.
Laboratory detection challenges and lack of implementation of or compliance with infection prevention and control measures contribute to the rapid transmission of CRE reported within hospital units, particularly intensive care units.
March 20, CDC and the Healthcare Infection Control Practices Advisory Committee (HICPAC) published recommendations for the prevention and control of CRE in acute care (inpatient) facilities. This document outlines recommendations for infection prevention and control as well as laboratory detection and reporting. Additionally this guidance recommends that acute care facilities should take the following actions:
- Review microbiology records for the preceding 6-12 months to identify CRE;
- If previously unrecognized CRE are found, perform a point prevalence culture survey of patients in the identified high-risk unit(s);
- Perform active surveillance cultures of patients with epidemiologic links to CRE-positive patients.
Detailed information for laboratories and instructions for isolate submission to MDH is at: www.health.state.mn.us/mls/LabAlerts/090224kpc.pdf.
We are available for consultation regarding laboratory testing and patient management, including surveillance and infection prevention and control measures.
Learn more about: Infection Control>>
2. GBS Disappointment
As reported in the February 13 MMWR,group B Streptococcus (GBS) continues to be a leading infectious cause of neonatal morbidity and mortality in the United States. In 2002, revised guidelines for prevention of early-onset GBS disease (EOD)(i.e., in infants <7 days of age) were issued and they recommended universal screening of all pregnant women for rectovaginal GBS colonization at 35-37 weeks' gestation and administration of intrapartum antibiotic prophylaxis (IAP) to carriers.
The article sadly notes that data from the EIP Active Bacterial Core surveillance (ABCs) system (including our data) reveal an increase in the overall rate of EOD from 2003 to 2006. The ABCs study area represents approximately 450,000 live births (11% of U.S. live births; 70% of infants were white, 20% black, and 10% of other race). The overall EOD incidence rate showed an initial downward trend from 2000 to 2003 (0.52 to 0.31 cases per 1,000 live births), followed by an increase from 2003 to 2006 (0.31 to 0.40 cases per 1,000 live births). When stratified by race, incidence from 2003 to 2006 among black infants increased significantly (0.53 to 0.86 cases per 1,000 live births), whereas incidence among white infants did not change significantly (0.26 to 0.29 cases per 1,000 live births).
In Minnesota we have seen a similar initial drop after 2002 with a leveling off since with 28 EOD cases in 1998 (0.43 per 1,000 live births), 25 (0.38 per 1,000 live births) in 1999, 33 (0.49) in 2000, 22 (0.33) in 2001, 27 (0.40) in 2002, 20 (0.29) in 2003, 26 (0.38) in 2004, 15 (0.21) in 2005, 25 (0.34) in 2006, 23 (0.31) in 2007, and 23 (0.31) in 2008.
This increase across all EIP sites was not anticipated and cannot yet be explained. The overall proportion receiving IAP (20%) was low, suggesting that missed opportunities for prevention might contribute more than prophylaxis failures to this remaining EOD burden. Other factors might influence the effectiveness of prevention and thus rates of disease, including higher GBS carriage rates among black women, the timing of screening, adequacy of specimen collection, appropriate laboratory processing, and implementation of adequate IAP. EIP sites are beginning to strategize on how best to answer the question of why this is happening.
Learn more about: GBS>>
March 24 is World TB Day in honor of Dr. Robert Koch who discovered the tubercle bacillus and gave his famous lecture on "The Etiology of Tuberculosis" on March 24, 1882. When he was 5 years old, he announced to his parents that he taught himself to read from viewing newspapers. He also is famous for identifying the cause of cholera, and he established rules for determining the cause of a disease (Koch's postulates). He won the Nobel Prize for Physiology or Medicine in 1905 for his TB work.
Nationwide, the rate of TB disease has decreased more than 10-fold since 1953. However, TB continues to be one of the deadliest diseases in the world; it still kills approximately 2 million people every year including more than 600 in the United States. Despite the fact that TB is preventable and curable, 211 cases of active TB disease were reported Minnesota in 2008. In 2007, the rate of TB disease in Minnesota (4.6/100,000) exceeded that of the nation (4.4/100,000) for the first time since national surveillance for TB began in 1953. Along with partner local public health agencies, we continue to investigate three large TB outbreaks in the state that began in 2008. More information on World TB Day is at http://www.health.state.mn.us/divs/idepc/diseases/tb/worldtbday.html.
Learn more about: World TB Day>>
Last week we noticed two Minnesota Salmonella Oranienburg cases that matched by PFGE. As usual, we immediately contacted and interviewed both cases, one being still hospitalized. Both cases had a history of recent travel on the same cruise ship that left a Florida port on February 15 to the Caribbean.
One of the cases is an adult female from the Twin Cities who flew to Florida and boarded the cruise the same day. Her onset of illness began the second day of the cruise. She had called the cruise line to report her illness and she was told she was there were other illnesses reported. The second case is an adult male from outstate Minnesota. He had bacteremia. He traveled to Minneapolis on February 13, stayed at a hotel near the airport, flew to Florida the next day, stayed at a hotel, and then on the next day boarded the same cruise as the first case. He had onset of illness 5 days into the cruise. He had three travel companions, and two also became ill but were no specimens were taken for bacterial culture.
We notified other states and late last Friday night received word from a New England state that they had a PFGE-matched S. Oranienburg case which had been interviewed and had also been on the same cruise; that person also had an ill travel companion.
CDC has a Vessel Sanitation Program and will be do further investigation including a likely on-board assessment of the cruise ship (but without any MDH volunteers, of which there are many).
Learn more about: Salmonella>>
5. Hib Update
We have not seen any other cases of Haemophilus influenzae type B(Hib) since the last issue of Bug Bytes when we discussed the 5 cases seen in 2008. However, other states are now beginning to see similar "break-out" Hib cases. Last week, the Pennsylvania Department of Health announced that 4 Hib cases in unvaccinated or incompletely vaccinated children <5 years of age were seen in the last 6 months. Isolates from 3 additional cases of H. influenzae invasive disease, also in unvaccinated children <5 years old from southeastern Pennsylvania have not yet been serotyped. Three of these seven children died.
In response to our report and other nationwide reports, the CDC issued a nationwide Health Advisory this week. Health care providers must be vigilant about ensuring that all young children are appropriately vaccinated with the 3 dose primary series of Hib vaccine.
Temporary deferral of the booster dose at 12 through 15 months of age for non-high risk children may have resulted in increased Hib carriage and transmission in non-symptomatic children, although our ongoing Hib survey in which we have obtained and tested nearly 1,600 oropharyngeal swabs has not supported this. There is enough Hib-containing vaccine for all U.S. children to receive the primary series. All children should complete the primary series by 7 months of age; high risk children should continue to receive the full primary series and the booster dose. In addition, using available Hib-containing vaccines has presented challenges associated with switching from the Merck to sanofi products for some providers. There are indications that these challenges have led to lower completion of the primary series. Preliminary information from sentinel immunization information systems (registries) in select states have indicated up to 10% lower coverage with the third Hib dose in the primary series compared to other vaccines (DTaP, PCV7) commonly administered at the same visit. In the scenario of booster dose deferral, it is even more important that all infants receive the complete primary series.
Learn more about: Hib>>
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