Active Laboratory-based Surveillance Research Articles

The 2022 West Nile Virus Season in Greece; A Quite Intense Season.

Since 2010, the West Nile virus (WNV) has been established in Greece. We describe the epidemiology of diagnosed human WNV infections in Greece with a focus on the 2022 season. During the transmission period, clinicians were sending samples from suspected cases for testing. Active laboratory-based surveillance was performed with immediate notification of diagnosed cases. We collected clinical information and interviewed patients on a timely basis to identify their place of exposure. Besides serological and molecular diagnostic methods, next-generation sequencing was also performed. In 2022, 286 cases of WNV infection were diagnosed, including 278 symptomatic cases and 184 (64%) cases with neuroinvasive disease (WNND); 33 patients died. This was the third most intense season concerning the number of WNND cases, following 2018 and 2010. Most (96%) cases were recorded in two regions, in northern and central Greece. The virus strain was a variant of previous years, clustering into the Central European subclade of WNV lineage 2. The 2022 WNV season was quite intense in Greece. The prompt diagnosis and investigation of cases are considered pivotal for the timely response, while the availability of whole genome sequences enables studies on the molecular epidemiology of the disease.

Carbapenemase genes and mortality in patients with carbapenem-resistant Enterobacterales, Atlanta, Georgia, 2011–2020

Background: Carbapenemase genes in carbapenem-resistant Enterobacterales (CP-CRE) may be transmitted between patients and bacteria. Reported rates of carbapenemase genes vary widely, and it is unclear whether having a carbapenemase gene portends worse outcomes given that all patients with CRE infections have limited treatment options. Methods: Using active population- and laboratory-based active surveillance data collected by the US CDC-funded Georgia Emerging Infections Program from 2011 to 2020, we assessed the frequency of carbapenemase genes in a convenience sample of CRE isolates using whole-genome sequencing (WGS), and we investigated risk factors for carbapenemase positivity. Only the first isolate per patient in a 30-day period was included. We compared characteristics of patients with CP-CRE and non–CP-CRE. Using multivariable log binomial regression, we assessed the association of carbapenemase gene positivity and 90-day mortality. Results: Of 284 CRE isolates, 171 isolates (60.2%) possessed a carbapenemase gene (Table 1), and KPC-3 was the most common carbapenemase gene (80.7%), with only 7 isolates possessing NDM (Table 2). No isolates possessed >1 carbapenemase gene, and most isolates were from urine (82.4%) (Table 1). Carbapenemase gene positivity was associated with lower age, male sex, black race, infection with Klebsiella pneumoniae, polymicrobial infection, having an indwelling medical device, receiving chronic dialysis, and prior stay in a long-term acute-care hospital, long-term care facility, and/or prior hospitalization in the last year. The 90-day mortality rates were similar in patients with non–CP-CRE and CP-CRE: 24.8% versus 25.7% (P = .86). In multivariable analysis, carbapenemase gene presence was not associated with 90-day mortality (adjusted risk ratio, 0.82; 95% CI, 0.50–1.35) when adjusting for CCI, infection with Klebsiella pneumoniae, and chronic dialysis use. Conclusions: The frequency of CP-CRE among CRE was high in this study, but unlike prior studies, the 90-day mortality rates wer similar in patients with CP-CRE compared to non–CP-CRE. Our results provide novel associations (eg, lower age, male sex, infection with Klebsiella pneumoniae, and indwelling medical devices) that infection preventionists could use to target high-risk patients for screening or isolation prior to CP-CRE detection.Disclosure: None

Epidemiological Trends of Racial Differences in Early- and Late-onset Group B Streptococcus Disease in Tennessee.

The rates of early-onset group B Streptococcus (GBS) disease (EOGBS) have declined since the implementation of universal screening and intrapartum antibiotic prophylaxis guidelines but late-onset (LOGBS) rates remain unchanged. Racial differences in GBS disease rates have been previously documented, with Black infants having higher rates of EOGBS and LOGBS, but it is not known if these have persisted. Therefore, we sought to determine the differences in EOGBS and LOGBS disease by race over the past decade in Tennessee. This study used active population-based and laboratory-based surveillance data for invasive GBS disease conducted through Active Bacterial Core surveillance in selected counties across Tennessee. We included infants younger than 90 days and who had invasive GBS disease between 2009 and 2018. A total of 356 GBS cases were included, with 60% having LOGBS. EOGBS and LOGBS had decreasing temporal trends over the study period. Overall, there were no changes in temporal trend noted in the rates of EOGBS and LOGBS among White infants. However, Black infants had significantly decreasing EOGBS and LOGBS temporal trends (relative risk [95% confidence interval], .87 [.79, .96] [P = .007] and .90 [.84-.97] [P = .003], respectively). Years after the successful implementation of the universal screening guidelines, our data revealed an overall decrease in LOGBS rates, primarily driven by changes among Black infants. More studies are needed to characterize the racial disparities in GBS rates, and factors driving them. Prevention measures such as vaccination are needed to have a further impact on disease rates.

Estimation of prevalence of dengue viral infection among clinically suspected patients attending a tertiary care centre in Uttar Pradesh, India

Background: Dengue virus infection is fastest spreading, mosquito borne viral disease in the world with an estimated 3.9 billion people at risk of infection. Dengue is notifiable disease in India, but real number of cases could not be identified many times due to the under-reporting or misdiagnosis of cases. The purpose of the present study was to estimate prevalence of dengue viral Infection among suspected patients attending a tertiary care centre.Methods: Blood samples from suspected patients were collected over a period of 1 year and were analysed for dengue virus specific IgM antibodies and NS1 antigen by immuno-chromatographic method.Results: Total 196 samples were tested out of which 43 (21.43%) showed laboratory evidence of dengue. Maximum samples were received during monsoon and post-monsoon period. Dengue sero-positivity was found to be highest in post monsoon period i.e., October-November. Maximum dengue positivity rate was found in the age group of 16-45 years.Conclusions: For estimation of true burden of dengue in India and its geographical mapping to control further disease transmission; laboratory-based active surveillance systems are required along with passive surveillance and control programs.

Meningococcal serogroups and surveillance: a systematic review and survey.

BackgroundMeningococcal disease continues to be a global public health concern due to its epidemic potential, severity, and sequelae. The global epidemiological data on circulating meningococcal serogroups have never been reviewed concurrently with the laboratory capacity for meningococcal surveillance at the national level. We, therefore, aimed to conduct a country-level review of meningococcal surveillance, serogroup distribution, and vaccine use.MethodsWe conducted a systematic literature review across six databases to identify studies (published January 1, 2010 to October 16, 2017) and grey literature reporting meningococcal serogroup data for the years 2010-2016. We performed independent random effects meta-analyses for serogroups A, B, C, W, X, Y, and other. We developed and circulated a questionnaire-based survey to surveillance focal points in countries (N = 95) with known regional bacterial meningitis surveillance programs to assess their surveillance capacity and summarized using descriptive methods.ResultsWe included 173 studies from 59 countries in the final analysis. The distribution of meningococcal serogroups differed markedly between countries and regions. Meningococcal serogroups C and W accounted for substantial proportions of meningococcal disease in most of Africa and Latin America. Serogroup B was the predominant cause of meningococcal disease in many locations in Europe, the Americas, and the Western Pacific. Serogroup Y also caused many cases of meningococcal disease in these regions, particularly in Nordic countries. Survey responses were received from 51 countries. All countries reported the ability to confirm the pathogen in-country, while approximately 30% either relied on reference laboratories for serogrouping (N = 10) or did not serogroup specimens (N = 5). Approximately half of countries did not utilize active laboratory-based surveillance system (N = 22). Nationwide use of a meningococcal vaccine varied, but most countries (N = 36) utilized a meningococcal vaccine at least for certain high-risk population groups, in private care, or during outbreaks.ConclusionsDue to the large geographical variations in circulating meningococcal serogroups, each country should continue to be monitored for changes in major disease-causing serogroups in order to inform vaccine and control policies. Similarly, laboratory capacity should be appropriately scaled up to more accurately understand local epidemiology and disease burden, as well as the impact of vaccination programs.

Epidemiology of Invasive Early-Onset and Late-Onset Group B Streptococcal Disease in the United States, 2006 to 2015

Invasive disease owing to group B Streptococcus (GBS) remains an important cause of illness and death among infants younger than 90 days in the United States, despite declines in early-onset disease (EOD; with onset at 0-6 days of life) that are attributed to intrapartum antibiotic prophylaxis (IAP). Maternal vaccines to prevent infant GBS disease are currently under development. To describe incidence rates, case characteristics, antimicrobial resistance, and serotype distribution of EOD and late-onset disease (LOD; with onset at 7-89 days of life) in the United States from 2006 to 2015 to inform IAP guidelines and vaccine development. This study used active population-based and laboratory-based surveillance for invasive GBS disease conducted through Active Bacterial Core surveillance in selected counties of 10 states across the United States. Residents of Active Bacterial Core surveillance areas who were younger than 90 days and had invasive GBS disease in 2006 to 2015 were included. Data were analyzed from December 2017 to April 2018. Group B Streptococcus isolated from a normally sterile site. Early-onset disease and LOD incidence rates and associated GBS serotypes and antimicrobial resistance. The Active Bacterial Core surveillance program identified 1277 cases of EOD and 1387 cases of LOD. From 2006 to 2015, EOD incidence declined significantly from 0.37 to 0.23 per 1000 live births (P < .001), and LOD rates remained stable (mean, 0.31 per 1000 live births). Among the mothers of 1277 infants with EOD, 617 (48.3%) had no indications for IAP and did not receive it, and 278 (21.8%) failed to receive IAP despite having indications. Serotype data were available for 1743 of 1897 patients (91.3%) from 7 sites that collect GBS isolates. Among patients with EOD, serotypes Ia (242 [27.3%]) and III (242 [27.3%]) were most common. Among patients with LOD, serotype III was most common (481 [56.2%]), and this increased from 2006 to 2015 from 0.12 to 0.20 cases per 1000 live births (P < .001). Serotype IV caused 53 cases (6.2%) of EOD and LOD combined. The 6 most common serotypes (Ia, Ib, II, III, IV, and V) caused 881 EOD cases (99.3%) and 853 LOD cases (99.7%). No β-lactam resistance was identified; 359 isolates (20.8%) tested showed constitutive clindamycin resistance. In 2015, an estimated 840 EOD cases and 1265 LOD cases occurred nationally. The rates of LOD among US infants are now higher than EOD rates. Combined with addressing IAP implementation gaps, an effective vaccine covering the most common serotypes might further reduce EOD rates and help prevent LOD, for which there is no current public health intervention.

1759. High Proportion of Discordant Results in Culture-Independent Diagnostic Tests (CIDT) for Shiga Toxin, Foodborne Disease Active Surveillance Network (FoodNet), 2012−2017

BackgroundFoodNet conducts active laboratory-based surveillance for 9 pathogens transmitted commonly through food, including Shiga toxin-producing E. coli (STEC). Adoption of CIDTs has allowed for rapid identification of Shiga toxin or Shiga toxin genes, but incorporating multiple test results with differing sensitivity and specificity complicates treatment decisions and public health surveillance. Between 2007 and 2017, FoodNet reported increases in the use of CIDTs and decreases in rates of confirmation by culture.MethodsWe examined STEC cases reported to FoodNet during 2012−2017 with a positive immunoassay (IA) or polymerase chain reaction (PCR) test performed at a clinical laboratory, followed by positive or negative test at a state public health laboratory. Three test type combinations were assessed (IA/IA, PCR/PCR, and IA/PCR) by state, symptoms, test discordance, and culture (cx) result.ResultsDuring 2012−2017, 8,298 (76% of all STEC reported) specimens were tested by IA or PCR at both a clinical and a public health laboratory, 58% by IA/PCR, 27% by IA/IA, and 25% by PCR/PCR; some specimens had more than one test at each laboratory. Among these, 8,132 (98%) were also tested by cx. Among the IA/PCR test results, 20% were discordant and 75% of these were cx-negative. Even more of IA/IA (27%) and PCR/PCR (24%) results were discordant, and 75% of these were cx-negative. A median of 24% of test results were discordant (range by state, 13%–44%). Persons with discordant test results were less likely to have diarrhea (91% vs. 97%) and bloody diarrhea (33% vs. 57%). During 2012–2017, discordant results increased for IA/PCR (14% to 22%), IA/IA (17% to 34%), and PCR/PCR (6% to 25%). Most (85%) specimens with discordant results were cx-negative and 8% did not have a cx.ConclusionAlmost a quarter of results were discordant, with marked variation by state, and most of these infections could not be confirmed by culture at the public health laboratory. Discordant results can pose problems for patient management. Including or excluding patients with discordant results also affects our ability to measure trends. Sensitivity and specificity of test types, test targets, and specimen transport must be considered when interpreting test results.Disclosures All authors: No reported disclosures.

Outbreak investigation of ceftriaxone-resistant Salmonella enterica serotype Typhi and its risk factors among the general population in Hyderabad, Pakistan: a matched case-control study

Pakistan is currently facing the largest outbreak of ceftriaxone-resistant Salmonella enterica serotype Typhi described to date. Here we aimed to report the outbreak investigation done in Hyderabad, Pakistan, and identify disease risk factors. We did an age-matched case-control (1:4) study, in which cases of ceftriaxone-resistant S Typhi were identified from active sentinal sites (three hospitals in Hyderabad, Pakistan), community, and laboratory-based surveillance. Ceftriaxone-resistant S Typhi infection (ie, resistance to ampicillin, chloramphenicol, co-trimoxazole, fluoroquinole, and ceftriaxone) was confirmed using blood culture. Healthy participants (controls) were enrolled for the first 200 people (cases) with ceftriaxone-resistant S Typhi. A structured questionnaire was administered to identify exposures 4 weeks before the illness (cases) or enrolment (controls). Cases were included if written informed consent was provided. Four controls were selected from the same community as the corresponding case, matched on age, being healthy at the time of enrolment, and with no febrile illness in the 4 weeks before enrolment. Samples of drinking water from households and community water sources (ie, hand pumps or taps in common areas outside households) were collected for testing. Conditional logistic regression analysis was used to assess the risk factors for ceftriaxone-resistant S Typhi outbreak in Hyderabad. Between Nov 30, 2016, and Dec 30, 2017, 486 people with ceftriaxone-resistant S Typhi were identified from Hyderabad. Of the 486 cases, 296 (61%) were male and 447 (92%) were aged 15 years or younger. Several factors were significantly associated with acquisition of ceftriaxone-resistant S Typhi, including male sex (adjusted odds ratio [aOR] 1·53, 95% CI 1·06-2·21), eating outside of the house (aOR 1·48, 1·01-2·19), exposure to a patient with S Typhi infection (aOR 3·81, 2·21-6·83), and a history of antimicrobial use (aOR 4·25, 2·53-7·13). Nine (69%) of 13 water samples taken from the households of people with ceftriaxone-resistant S Typhi infection were positive for Escherichia coli, indicating faecal contamination. S Typhi DNA was detected in 12 (22%) of 55 water samples from community water sources. Geospatial mapping showed clustering of cases around sewerage lines. Hyderabad faces the largest reported outbreak of ceftriaxone-resistant S Typhi. The outbreak is suspected to be attributed to the contaminated drinking water, especially the mixing of sewage with drinking water. The risk of ceftriaxone-resistant S Typhi infection is increased among children aged 15 years and younger, male individuals, and those eating outside the house. Vaccination and chlorination of water are recommended for the containment of the outbreak. None.

Comparison of 30- and 90-Day Mortality Rates in Patients with Cultures Positive for Carbapenem-resistant Enterobacteriaceae and Acinetobacter in Atlanta, 2011–2015

BackgroundCarbapenem-resistant Enterobacteriaceae (CRE) and Acinetobacter baumannii (CRAB) pose a threat to public health, but comparisons of disease burden are limited. We compared survival in patients following cultures positive for CRE or CRAB.MethodsThe Georgia Emerging Infections Program performs active population-based and laboratory-based surveillance for CRE and CRAB in metropolitan Atlanta, GA. Using standard CDC definitions, we included patients who had incident carbapenem-nonsusceptible E. coli, Klebsiella spp., Enterobacter spp., or Acinetobacter baumannii isolated from urine only (noninvasive infection) or a sterile site (invasive infection) between 8/2011 and 12/2015. Death dates, verified by Georgia Vital Statistics records, were used to calculate 30- and 90-day mortality rates. We used the chi-square test for mortality rates and the log-rank test for survival analysis to 90 days to compare patients with invasive CRAB, noninvasive CRAB, invasive CRE, and noninvasive CRE.ResultsThere were 535 patients with CRE (87 invasive, 448 noninvasive) and 279 (78 invasive, 201 noninvasive) with CRAB. Nearly all patients with CRE and CRAB had healthcare exposures (97.2% vs. 100%) and most were immunosuppressed (62.6% vs. 56.3%). Both 30-day (24.4% vs. 18.3%, p = 0.04) and 90-day (37.6% vs. 30.5%, p = 0.04) mortality were higher in patients with CRAB than CRE. Patients with invasive infections were more likely to die at 90 days than those with noninvasive infections (53.3% vs. 38.4%, p < 0.0001). Overall mortality rates for invasive infection were similar between CRAB and CRE at 30 (44.9% vs. 34.5% p = 0.2) and 90 days (59.0% vs. 48.3%, p = 0.2). Using survival analysis at 90 days, invasive CRAB had the worst outcomes, followed by invasive CRE, noninvasive CRAB and noninvasive CRE (p < 0.0001, see Figure).Conclusion Ninety-day mortality for invasive infections with CRE and CRAB was ~50%, and patients with CRAB had lower survival than those with CRE, suggesting that prevention efforts may need to prioritize CRAB as highly as CRE in facilities with endemic CRAB. With the high proportion of healthcare exposures and immunosuppression, these infections may signify poor prognosis or directly contribute to mortality.Disclosures All authors: No reported disclosures.

Changing epidemiology of candidaemia in Australia.

Knowledge of contemporary epidemiology of candidaemia is essential. We aimed to identify changes since 2004 in incidence, species epidemiology and antifungal susceptibilities of Candida spp. causing candidaemia in Australia. These data were collected from nationwide active laboratory-based surveillance for candidaemia over 1 year (within 2014-2015). Isolate identification was by MALDI-TOF MS supplemented by DNA sequencing. Antifungal susceptibility testing was performed using Sensititre YeastOne™. A total of 527 candidaemia episodes (yielding 548 isolates) were evaluable. The mean annual incidence was 2.41/105 population. The median patient age was 63 years (56% of cases occurred in males). Of 498 isolates with confirmed species identity, Candida albicans was the most common (44.4%) followed by Candida glabrata complex (26.7%) and Candida parapsilosis complex (16.5%). Uncommon Candida species comprised 25 (5%) isolates. Overall, C. albicans (>99%) and C. parapsilosis (98.8%) were fluconazole susceptible. However, 16.7% (4 of 24) of Candida tropicalis were fluconazole- and voriconazole-resistant and were non-WT to posaconazole. Of C. glabrata isolates, 6.8% were resistant/non-WT to azoles; only one isolate was classed as resistant to caspofungin (MIC of 0.5 mg/L) by CLSI criteria, but was micafungin and anidulafungin susceptible. There was no azole/echinocandin co-resistance. We report an almost 1.7-fold proportional increase in C. glabrata candidaemia (26.7% versus 16% in 2004) in Australia. Antifungal resistance was generally uncommon, but azole resistance (16.7% of isolates) amongst C. tropicalis may be emerging.

Persistent Sex Disparities in Invasive Pneumococcal Diseases in the Conjugate Vaccine Era.

Few studies have characterized the role of sex on the incidence of invasive pneumococcal disease (IPD). We examined sex differences in rates of IPD, and trends after the introduction of pneumococcal conjugate vaccines (PCVs). We used active population and laboratory-based IPD surveillance data from the Centers for Disease Control and Prevention Active Bacterial Core surveillance program (1998-2013) in Tennessee. Population-based rates of IPD by sex, race, age group, and PCV era were calculated. Rates were compared using incidence rate ratios. Throughout the study years, rates of IPD were higher in male than in female subjects, particularly in children <2 years and adults 40-64 years of age, with male subjects having IPD rates 1.5-2 times higher than female subjects. The proportions of comorbid conditions were similar in male and female subjects . Sex rate differences persisted after stratification by race. Although the introductions of 7-valent PCV (PCV7) and 13-valent PCV (PCV13) were associated with declines in IPD rates in both sexes, rates of IPD after PCV13 were still significantly higher in male than in female subjects among children and adults 40-64 and >74 years of age. Rates of IPD were generally higher in male than in female subjects. These sex differences were observed in different race groups and persisted after introduction of both PCVs.

Epidemiology of Carbapenem-Resistant Enterobacteriaceae in 7 US Communities, 2012-2013.

Carbapenem-resistant Enterobacteriaceae (CRE) are increasingly reported worldwide as a cause of infections with high-mortality rates. Assessment of the US epidemiology of CRE is needed to inform national prevention efforts. To determine the population-based CRE incidence and describe the characteristics and resistance mechanism associated with isolates from 7 US geographical areas. Population- and laboratory-based active surveillance of CRE conducted among individuals living in 1 of 7 US metropolitan areas in Colorado, Georgia, Maryland, Minnesota, New Mexico, New York, and Oregon. Cases of CRE were defined as carbapenem-nonsusceptible (excluding ertapenem) and extended-spectrum cephalosporin-resistant Escherichia coli, Enterobacter aerogenes, Enterobacter cloacae complex, Klebsiella pneumoniae, or Klebsiella oxytoca that were recovered from sterile-site or urine cultures during 2012-2013. Case records were reviewed and molecular typing for common carbapenemases was performed. Demographics, comorbidities, health care exposures, and culture source and location. Population-based CRE incidence, site-specific standardized incidence ratios (adjusted for age and race), and clinical and microbiological characteristics. Among 599 CRE cases in 481 individuals, 520 (86.8%; 95% CI, 84.1%-89.5%) were isolated from urine and 68 (11.4%; 95% CI, 8.8%-13.9%) from blood. The median age was 66 years (95% CI, 62.1-65.4 years) and 284 (59.0%; 95% CI, 54.6%-63.5%) were female. The overall annual CRE incidence rate per 100<000 population was 2.93 (95% CI, 2.65-3.23). The CRE standardized incidence ratio was significantly higher than predicted for the sites in Georgia (1.65 [95% CI, 1.20-2.25]; P < .001), Maryland (1.44 [95% CI, 1.06-1.96]; P = .001), and New York (1.42 [95% CI, 1.05-1.92]; P = .048), and significantly lower than predicted for the sites in Colorado (0.53 [95% CI, 0.39-0.71]; P < .001), New Mexico (0.41 [95% CI, 0.30-0.55]; P = .01), and Oregon (0.28 [95% CI, 0.21-0.38]; P < .001). Most cases occurred in individuals with prior hospitalizations (399/531 [75.1%; 95% CI, 71.4%-78.8%]) or indwelling devices (382/525 [72.8%; 95% CI, 68.9%-76.6%]); 180 of 322 (55.9%; 95% CI, 50.0%-60.8%) admitted cases resulted in a discharge to a long-term care setting. Death occurred in 51 (9.0%; 95% CI, 6.6%-11.4%) cases, including in 25 of 91 cases (27.5%; 95% CI, 18.1%-36.8%) with CRE isolated from normally sterile sites. Of 188 isolates tested, 90 (47.9%; 95% CI, 40.6%-55.1%) produced a carbapenemase. In this population- and laboratory-based active surveillance system in 7 states, the incidence of CRE was 2.93 per 100<000 population. Most CRE cases were isolated from a urine source, and were associated with high prevalence of prior hospitalizations or indwelling devices, and discharge to long-term care settings.

Pseudo-outbreak of rotavirus infection in a neonatal intensive care unit.

A rotavirus outbreak in a neonatal intensive care unit (NICU) may have catastrophic consequences for young infants receiving critical care. From May 13, 2011 to July 11, 2011, a significant increase in stool samples testing positive for rotavirus antigens in the NICU of a university affiliated hospital was observed. Due to lack of clinical presentations suggestive of rotavirus infection in the patients and the rarity of rotavirus infection in the NICU in the past, a pseudo-outbreak was suspected. Infection control measures were reinforced initially. To investigate the outbreak, a prospective laboratory-based active surveillance of all infants in the NICU was conducted right after the cluster was identified. Repeated testing using a modified enzyme immunoassay (EIA) kit, rotavirus RNA polyacrylamide gel electrophoresis (PAGE), reverse transcription polymerase chain reaction (RT-PCR), and retrospective chart review methods were used to confirm the pseudo-outbreak. Seven infants in the NICU, with or without gastrointestinal symptoms, tested positive for the rotavirus antigen using the old version of an EIA kit, which indicated a possible outbreak. Active surveillance with repeated tests for recollected stool samples using a modified EIA kit showed negative results in all 24 infants in the NICU. Seven stored stool samples from four infants, which previously tested positive for the rotavirus antigen, tested negative for rotavirus using the modified EIA kit, PAGE, and RT-PCR. Chart reviews showed no clinical difference between index cases and controls. False positivity might arise from unsatisfactory specificity of the old EIA kit. After the introduction of the modified EIA kit, no rotavirus was detected in the NICU for at least 7 months. This cluster of patients who tested positive for the rotavirus antigen in stools was confirmed to be a pseudo-outbreak. Interpretation of the old EIA for rotavirus in an NICU setting should be done with caution until the mechanism of the false-positive reaction is elucidated.

Thirty-Day Laboratory-Based Surveillance for Carbapenem-Resistant Enterobacteriaceae in the Minneapolis-St. Paul Metropolitan Area

Carbapenem-resistant Enterobacteriaceae (CRE) are a growing problem in the United States. We explored the feasibility of active laboratory-based surveillance of CRE in a metropolitan area not previously considered to be an area of CRE endemicity. We provide a framework to address CRE surveillance and to monitor changes in the incidence of CRE infection over time.

Population-based Surveillance for Bacterial Meningitis in China, September 2006–December 2009

During September 2006-December 2009, we conducted active population and sentinel laboratory-based surveillance for bacterial meningitis pathogens, including Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae type b, in 4 China prefectures. We identified 7,876 acute meningitis and encephalitis syndrome cases, including 6,388 among prefecture residents. A total of 833 resident cases from sentinel hospitals met the World Health Organization case definition for probable bacterial meningitis; 339 of these cases were among children <5 years of age. Laboratory testing confirmed bacterial meningitis in 74 of 3,391 tested cases. The estimated annual incidence (per 100,000 population) of probable bacterial meningitis ranged from 1.84 to 2.93 for the entire population and from 6.95 to 22.30 for children <5 years old. Active surveillance with laboratory confirmation has provided a population-based estimate of the number of probable bacterial meningitis cases in China, but more complete laboratory testing is needed to better define the epidemiology of the disease in this country.

Seasonality of acute otitis media and the role of respiratory viral activity in children.

Acute otitis media (AOM) occurs as a complication of viral upper respiratory tract infections in young children. AOM and respiratory viruses both display seasonal variation. Our objective was to examine the temporal association between circulating respiratory viruses and the occurrence of pediatric ambulatory care visits for AOM. This retrospective study included 9 seasons of respiratory viral activity (2002 to 2010) in Utah. We used Intermountain Healthcare electronic medical records to assess community respiratory viral activity via laboratory-based active surveillance and to identify children <18 years with outpatient visits and International Classification of Diseases, Ninth Revision codes for AOM. We assessed the strength of the association between AOM and individual respiratory viruses using interrupted time series analyses. During the study period, 96,418 respiratory viral tests were performed; 46,460 (48%) were positive. The most commonly identified viruses were respiratory syncytial virus (22%), rhinovirus (8%), influenza (8%), parainfluenza (4%), human metapneumovirus (3%) and adenovirus (3%). AOM was diagnosed during 271,268 ambulatory visits. There were significant associations between peak activity of respiratory syncytial virus, human metapneumovirus, influenza A and office visits for AOM. Adenovirus, parainfluenza and rhinovirus were not associated with visits for AOM. Seasonal respiratory syncytial virus, human metapneumovirus and influenza activity were temporally associated with increased diagnoses of AOM among children. These findings support the role of individual respiratory viruses in the development AOM. These data also underscore the potential for respiratory viral vaccines to reduce the burden of AOM.

Current status of measles in the Republic of Korea: an overview of case-based and seroepidemiological surveillance scheme

Following the Five Year Measles Elimination Program, measles has been declared eliminated from the Republic of Korea since 2006. However, there remain challenges related to the surveillance of measles in the postelimination phase. Even though the routine surveillance system has revealed a gradual decrease in the number of reported cases since 2002, 4 resurgences have occurred, notably due to outbreaks. Because vaccine-modified measles is becoming widespread due to high vaccination coverage, conducting laboratory confirmation in each case becomes important. Moreover, susceptible individuals with measles have been identified through seroprevalence studies. Lastly, the efforts to improve the timeliness of measles reporting have led to the establishment of an active laboratory-based surveillance network, which has shortened the interval between diagnosis and notification. In these circumstances, searching for more sensitive and effective surveillance measures is important for maintaining the elimination status and preventing future outbreaks of measles in Korea.

Estimating the burden of acute gastroenteritis and foodborne illness caused by Campylobacter, Salmonella, and Vibrio parahaemolyticus by using population-based telephone survey data, Miyagi Prefecture, Japan, 2005 to 2006.

Most cases of acute gastroenteritis and foodborne disease are not ascertained by public health surveillance because the ill person does not always seek medical care and submit a stool sample for testing, and the laboratory does not always test for or identify the causative organism. We estimated the total burden of acute gastroenteritis in Miyagi Prefecture, Japan, using data from two 2-week cross-sectional, population-based telephone surveys conducted in 2006 and 2007. To estimate the number of acute gastroenteritis illnesses caused by Campylobacter, Salmonella, and Vibrio parahaemolyticus in Miyagi Prefecture, we determined the number of cases for each pathogen from active laboratory-based surveillance during 2005 to 2006 and adjusted for seeking of medical care and submission of stool specimens by using data from the population-based telephone surveys. Monte Carlo simulation was used to incorporate uncertainty. The prevalence of acute gastroenteritis in the preceding 4 weeks was 3.3% (70 of 2,126) and 3.5% (74 of 2,121) in the winter and summer months, yielding an estimated 44,200 episodes of acute gastroenteritis each year in this region. Among people with acute gastroenteritis, the physician consultation rate was 32.0%, and 10.9% of persons who sought care submitted a stool sample. The estimated numbers of Campylobacter-, Salmonella-, and V. parahaemolyticus -associated episodes of acute gastroenteritis were 1,512, 209, and 100 per 100,000 population per year, respectively, in this region. These estimates are significantly higher than the number of reported cases in surveillance in this region. Cases ascertained from active surveillance were also underrepresented in the present passive surveillance, suggesting that complementary surveillance systems, such as laboratory-based active surveillance in sentinel sites, are needed to monitor food safety in Japan.

Geographic Variation in Invasive Pneumococcal Disease Following Pneumococcal Conjugate Vaccine Introduction in the United States

Rates of invasive pneumococcal disease (IPD) varied among the United States before pneumococcal conjugate vaccine (PCV7) introduction. We compared trends in IPD rates among diverse US sites over 10 years since PCV7 introduction. Patients with IPD of all ages were identified through active population and laboratory-based surveillance in 8 geographic areas under continuous surveillance during 1998-2009. Isolates were serotyped. IPD incidence rates and percent changes were calculated by site, serotype group, age, and year. Reductions in rates of IPD ranged, by site, from 19 to 29.9 cases per 100,000 population during 1998-1999 to 11.2-18.0 cases per 100,000 population during 2009 (rate reduction, 5.1-15.3 cases per 100,000 population). Reductions in IPD rates among children aged <5 years ranged from 35.7 to 117.2 cases per 100,000 population across the sites. Reductions in rates of IPD due to PCV7 serotypes were seen in all age groups at all sites, ranging from 12 to 21.4 cases per 100,000 population during 1998-1999 to <2 cases per 100,000 population during 2009 (92%-98% reductions). Serotype 19A rates ranged from 0.4 to 1.5 cases per 100,000 population during 1998-1999 to 1.3 to 3.4 cases per 100,000 population during 2009 (rate difference, 0.9-2.8 cases per 100,000 population); modest increases were observed for most age groups across the sites. Rates of IPD due to all other serotypes ranged from 6.3 to 10.3 cases per 100,000 population during 1998-1999 to 8.3-13.6 cases per 100,000 population during 2009 (rate difference, -0.4 to 5.7 cases per 100,000 population). Across the sites, the greatest rate increases were seen in the 50-64 and >65 year age groups. Reductions in IPD due to vaccine serotypes were consistent across sites. Changes in serotype 19A and all other serotypes were variable. Although relative increases in non-vaccine type serotypes were large in some sites, absolute rate increases were small.

Impact of rotavirus vaccination on laboratory confirmed cases in Belgium

Rotavirus vaccines were introduced in Belgium in 2006 and recommended in the universal schedule in January 2007. We measured the impact of rotavirus vaccination through an active laboratory-based surveillance system. In 2008, the number of laboratory confirmed rotavirus cases declined by 61.4% (95% CI 60.2–62.6%) compared to the 2005–2006 pre-vaccination period, with the highest decline in children <1 year (80.1%; 95% CI 78.7–81.4%). The rotavirus season was delayed compared to pre-vaccination seasons. Laboratory data provide a crude estimation of vaccination impact, but analysis of in-patient data will be needed to assess the impact on severe disease.