Shiga Toxin 1-Producing Shigella sonnei Infections, California, United States, 2014-2015.

Shiga toxins (Stx) are primarily associated with Shiga toxin-producing Escherichia coli and Shigella dysenteriae serotype 1. Stx production by other shigellae is uncommon, but in 2014, Stx1-producing S. sonnei infections were detected in California. Surveillance was enhanced to test S. sonnei isolates for the presence and expression of stx genes, perform DNA subtyping, describe clinical and epidemiologic characteristics of case-patients, and investigate for sources of infection. During June 2014-April 2015, we identified 56 cases of Stx1-producing S. sonnei, in 2 clusters. All isolates encoded stx1 and produced active Stx1. Multiple pulsed-field gel electrophoresis patterns were identified. Bloody diarrhea was reported by 71% of case-patients; none had hemolytic uremic syndrome. Some initial cases were epidemiologically linked to travel to Mexico, but subsequent infections were transmitted domestically. Continued surveillance of Stx1-producing S. sonnei in California is necessary to characterize its features and plan for reduction of its spread in the United States.

Two Listeria monocytogenes Pseudo-outbreaks Caused by Contaminated Laboratory Culture Media.

Listeriosis is a serious foodborne infection that disproportionately affects elderly adults, pregnant women, newborns, and immunocompromised individuals. Diagnosis is made by culturing Listeria monocytogenes from sterile body fluids or from products of conception. This report describes the investigations of two listeriosis pseudo-outbreaks caused by contaminated laboratory media made from sheep blood.

Transmission of 2009 pandemic influenza A (H1N1) virus among healthcare personnel-Southern California, 2009.

OBJECTIVE: In April 2009, 2009 pandemic influenza A (H1N1) (hereafter, pH1N1) virus was identified in California, which caused widespread illness throughout the United States. We evaluated pH1N1 transmission among exposed healthcare personnel (HCP) and assessed the use and effectiveness of personal protective equipment (PPE) early in the outbreak. DESIGN: Cohort study. SETTING: Two hospitals and 1 outpatient clinic in Southern California during March 28-April 24, 2009. PARTICIPANTS: Sixty-three HCP exposed to 6 of the first 8 cases of laboratory-confirmed pH1N1 in the United States. METHODS: Baseline and follow-up questionnaires were used to collect demographic, epidemiologic, and clinical data. Paired serum samples were obtained to test for pH1N1-specific antibodies by microneutralization and hemagglutination-inhibition assays. Serology results were compared with HCP work setting, role, and self-reported PPE use. RESULTS: Possible healthcare-associated pH1N1 transmission was identified in 9 (14%) of 63 exposed HCP; 6 (67%) of 9 seropositive HCP had asymptomatic infection. The highest attack rates occurred among outpatient HCP (6/19 [32%]) and among allied health staff (eg, technicians; 8/33 [24%]). Use of mask or N95 respirator was associated with remaining seronegative (P = .047). Adherence to PPE recommendations for preventing transmission of influenza virus and other respiratory pathogens was inadequate, particularly in outpatient settings. CONCLUSIONS: pH1N1 transmission likely occurred in healthcare settings early in the pandemic associated with inadequate PPE use. Organizational support for a comprehensive approach to infectious hazards, including infection prevention training for inpatient- and outpatient-based HCP, is essential to improve HCP and patient safety.

Spatial and temporal clustering of Kawasaki syndrome cases.

BACKGROUND: The etiology of Kawasaki syndrome (KS) remains unknown despite 30 years of intensive search for an agent. Epidemiologic clues to a possible infectious etiology include the seasonal distribution of cases, the previous occurrence of epidemics, the clinical features of the syndrome that mimic other infectious rash/fever illnesses in children, the self-limited nature of the illness, and the peak age incidence in the toddler years. METHODS: We examined the epidemiology and spatial and temporal distribution of KS cases in San Diego County, California during the 6-year period from 1998 to 2003. Clustering in space and time was analyzed using geo-referenced data with the K-function, the local G-statistic, and Knox statistic. RESULTS: A total of 318 patients were identified through active surveillance. The overall annual incidence was 21.7/100,000 in children <5 years, with rates in whites, white Hispanics, and Asian/Pacific Islanders of 15.3, 20.2, and 45.9/100,000, respectively. The Knox test showed significant clustering of cases within the space-time interval of 3 km and 3-5 days. CONCLUSIONS: This is the first study of KS cases to use geo-referenced point pattern analysis to detect spatial and temporal clustering of KS cases. These data suggest that an infectious agent triggers the immunologic cascade of KS.

Delayed diagnosis by physicians contributes to the development of coronary artery aneurysms in children with Kawasaki syndrome.

BACKGROUND: A diagnosis of Kawasaki syndrome is based on clinical criteria with nonspecific laboratory findings, and there is a substantial risk of coronary artery aneurysms if treatment with intravenous immunoglobulin is delayed. In this study, we examined the contributions of sociodemographic factors and parent and physician behavior to the development of coronary artery aneurysms in children with Kawasaki syndrome. METHODS: We performed a retrospective, case-control chart review of Kawasaki syndrome patients treated at our institution during an 11-year period (1991-2002). Of 324 patients, 21 patients had coronary artery aneurysms and were matched with 81 Kawasaki syndrome control patients without coronary artery aneurysms. RESULTS: Patients who developed coronary artery aneurysms were more likely to have had their diagnosis established after 10 days of fever as a result of a delay in physician recognition of Kawasaki syndrome. In addition, these patients were also more likely to have been hospitalized at an outside facility with an erroneous diagnosis, to have had a greater number of healthcare visits before diagnosis, to have sought medical care in Mexico, to lack medical insurance and to speak Spanish as a primary language. Independent predictors of delayed diagnosis included incomplete clinical signs of Kawasaki syndrome, seeking health care in Mexico, and being hospitalized at an outside facility with a different diagnosis. CONCLUSIONS: Increased risk of coronary artery aneurysms is associated with a delay in diagnosis by physicians and not with a delay in seeking medical consultation by parents. Sociodemographic factors influence the likelihood that patients will have a delayed diagnosis.

Acute disseminated encephalomyelitis in childhood: epidemiologic, clinical and laboratory features.

BACKGROUND: Acute disseminated encephalomyelitis (ADEM) is a central nervous system demyelinating disease that usually follows an apparently benign infection in otherwise healthy young persons. The epidemiology, infectious antecedents and pathogenesis of ADEM are poorly characterized, and some ADEM patients are subsequently diagnosed with multiple sclerosis (MS). METHODS: We retrospectively (1991-1998) and prospectively (1998-2000) studied all persons aged < 20 years diagnosed with ADEM from the 3 principal pediatric hospitals in San Diego County, CA, during 1991-2000. Acute neurologic abnormalities and imaging evidence of demyelination were required for study inclusion. Epidemiologic variables, risk factors, clinical course, laboratory and radiographic findings, neuropathology and treatment data were analyzed. Interleukin (IL)-12, interferon-gamma (IFN-gamma) and IL-10 were assayed in blinded manner on cerebrospinal fluid (CSF) obtained prospectively from a subset of ADEM cases and compared with CSF from patients with enteroviral (EV) meningoencephalitis confirmed by polymerase chain reaction (PCR) and controls without pleocytosis. RESULTS: Data were analyzed on 42 children and adolescents diagnosed with ADEM during 1991-2000, and CSF IL-12, IFN-gamma and IL-10 levels were compared among ADEM (n = 14), EV meningoencephalitis (n = 14) and controls without pleocytosis (n = 28). Overall incidence of ADEM was 0.4/100,000/year; incidence quadrupled during 1998-2000 compared with earlier years. No gender, age stratum, ethnic group or geographic area was disproportionately affected. A total of 4 (9.5%) patients initially diagnosed with ADEM were subsequently diagnosed with MS after multiple episodes of demyelination. Although most children eventually recovered, 2 died, including 1 of the 3 ultimately diagnosed with MS. Magnetic resonance imaging was required for diagnosis among 74% of patients; computerized tomography findings were usually normal. Patients with EV had significantly higher mean CSF IFN-gamma (P = 0.005) and IL-10 (P = 0.05) than patients with ADEM and controls without CSF pleocytosis. CSF from ADEM patients had CSF cytokine values statistically similar to those of 3 patients subsequently diagnosed with MS. CONCLUSIONS: ADEM is a potentially severe demyelinating disorder likely to be increasingly diagnosed as more magnetic resonance imaging studies are performed on patients with acute encephalopathy. Further characterization of the central nervous system inflammatory response will be needed to understand ADEM pathogenesis, to improve diagnostic and treatment strategies and to distinguish ADEM from MS.