Outbreak epidemiologically linked with a composite product of beef, mechanically separated chicken and textured vegetable protein contaminated with multiple serotypes of Salmonella enterica including multidrug-resistant Infantis, California 2016.

A salmonellosis outbreak occurred at a California prison in April and May 2016. In a cohort study of 371 inmates, persons who consumed dishes from the prison kitchen made from ground meat had a higher attack rate (15%) than those who did not (4%) (risk ratio 3.4, 95% CI 1.1-10.6). The ground meat product was composed exclusively of beef, mechanically separated chicken (MSC) and textured vegetable protein; eight of eight lots of the product collected from the prison and processing facility were contaminated with Salmonella enterica of eight serotypes and 17 distinct PFGE patterns, including multidrug-resistant S. Infantis. Either the MSC or the beef could have been the source of the particular strains of S. enterica isolated from patients or the product. The microbiological evidence is most consistent with MSC as the source of the high levels of S. enterica in the epidemiologically linked meat product. Our findings contribute to the growing body of evidence about the hazard posed by the use of products containing raw mechanically separated poultry in kitchens in institutions.

Outbreak of Legionnaires' disease associated with cooling towers at a California state prison, 2015.

A large outbreak of Legionnaires' disease occurred at a California state prison in August 2015. We conducted environmental and epidemiological investigations to identify the most likely source of exposure and characterise morbidity. Sixty-four inmates had probable Legionnaires' disease; 14 had laboratory-confirmed legionellosis. Thirteen (17%) inmates were hospitalised; there were no deaths. Ill inmates were more likely to be ⩾65 years old (P < 0.01), have the chronic obstructive pulmonary disease (P < 0.01), diabetes mellitus (P = 0.02), hepatitis C infection (P < 0.01), or end-stage liver disease (P < 0.01). The case-patients were in ten housing units throughout the prison grounds. All either resided in or were near the central clinical building (for appointments or yard time) during their incubation periods. Legionella pneumophila serogroup 1 was cultured from three cooling towers on top of the central medical clinic (range, 880-1200 cfu/ml). An inadequate water management program, dense biofilm within the cooling towers, and high ambient temperatures preceding the outbreak created an ideal environment for Legionella sp. proliferation. All state prisons were directed to develop local operating procedures for maintaining their cooling towers and the state health department added a review of the maintenance plans to their environmental inspection protocol.

Giardiasis outbreak at a camp after installation of a slow-sand filtration water-treatment system.

In July and August 2007, a giardiasis outbreak affected attendees of a private recreational camp in California. Twenty-six persons had laboratory-confirmed giardiasis; another 24 had giardiasis-like illness with no stool test. A retrospective cohort study determined that showering was associated with illness (adjusted odds ratio 3·1, 95% confidence interval 1·1-9·3). Two days before the outbreak began, the camp had installed a slow-sand water filtration system that included unsterilized sand. Review of historical water-quality data identified substantially elevated total coliform and turbidity levels in sand-filtered spring water used for showering during the suspected exposure period. Unfiltered spring water tested at the same time had acceptable coliform and turbidity levels, implicating the filtration system as the most likely contamination source. To prevent waterborne illness, slow-sand water filtration systems should use sterilized sand, and slow-sand-filtered water should not be used for any purpose where inadvertent ingestion could occur until testing confirms its potability.

Point-source outbreak of coccidioidomycosis in construction workers.

Coccidioidomycosis results from inhaling spores of the fungus Coccidioides spp. in soil or airborne dust in endemic areas. We investigated an outbreak of coccidioidomycosis in a 12-person civilian construction crew that excavated soil during an underground pipe installation on Camp Roberts Military Base, California in October 2007. Ten (83.3%) workers developed symptoms of coccidioidomycosis; eight (66.7%) had serologically confirmed disease, seven had abnormal chest radiographs, and one developed disseminated infection; none used respiratory protection. A diagnosis of coccidioidomycosis in an eleventh worker followed his exposure to the outbreak site in 2008. Although episodic clusters of infections have occurred at Camp Roberts, the general area is not associated with the high disease rates found in California's San Joaquin Valley. Measures to minimize exposure to airborne spores during soil-disrupting activities should be taken before work begins in any coccidioides-endemic area, including regions with only historic evidence of disease activity.

Epithelial ovarian cancer and the ability to conceive.

Relationships between ovarian cancer and ability to conceive were explored in a case-control study of 188 women with histologically confirmed epithelial ovarian cancer and 539 control women in the San Francisco Bay Area. Control women consisted of two groups: those hospitalized without cancer, matched to cases by age, race, and hospital of diagnosis (n = 280); and those selected from the general population by random digital dialing, matched to cases by age, race, and telephone prefix (n = 259). Ovarian cancer risk among nulliparous (but not parous) women was positively associated with a history of unsuccessful attempts to conceive, of physician-diagnosed infertility, and of doubts about ability to conceive. Among all women, risk increased with increasing years of unprotected intercourse (P value for trend = 0.02). Risk among women having 10 or more yr of unprotected intercourse was 1.8 relative to that among women having less than 2 such yr (P = 0.01). This association was independent of parity, oral contraceptive use, and estimated years of ovulation, each associated with ovarian cancer. Further, duration of unprotected intercourse combined multiplicatively with each of these latter characteristics in increasing ovarian cancer risk. For example, while cancer risk exhibited a 2-fold range from lowest to highest years of unprotected intercourse and a 4-fold range from lowest to highest years of ovulation, risk among women in the highest joint category of these characteristics was 8 times that of women in the lowest category. We believe that some abnormality of ovulation that reduces the likelihood of conception plays a role in epithelial ovarian cancer.

Group B streptococcal bacteremia in adults. Five years' experience and a review of the literature.

The importance of group B streptococcus (GBS) as a cause of serious infectious disease among adults is not widely appreciated. In adults, the modes of acquisition and transmission are unknown. Since most hospital-based studies of GBS bacteremia in adults consist of small numbers of patients, the clinical spectrum of disease is not well described. Our retrospective study reviews the clinical features, antimicrobial therapy, and risk factors for mortality of 32 adult patients (18 women and 14 men) with GBS bacteremia and compares the proportion of isolates from the different beta-hemolytic streptococci sero-groups. We found that 39% of isolates from adult blood cultures were group B, a frequency nearly identical to that of group A streptococcal bacteremia. Most (66%) adult patients were more than 50 years old. Primary bacteremia was the most frequent clinical diagnosis, occurring in 7 (22%) of 32 patients. Nonhematologic cancer was the most frequently associated condition (25%). Nineteen percent of the patients had diabetes mellitus. The overall mortality rate was 31% and was significantly associated with increasing age. Our results are compared to those obtained by a review of all 5 previous comparable studies and demonstrate that GBS bacteremia is a serious infection in adults with increased mortality related to advancing age.

Development of a population-specific risk assessment to predict elevated blood lead levels in Santa Clara County, California.

OBJECTIVES: To determine: (1) the prevalence of a blood lead level (PbB) of 10 micrograms/dL or greater and 20 micrograms/dL or greater among children aged 6 to 72 months attending the Santa Clara County (SCC), California, public clinics, (2) risk factors for elevated PbB in this population, and (3) whether an SCC public clinic population-specific risk-assessment tool and a five-question lead poisoning questionnaire developed by the Centers for Disease Control and Prevention are useful for prospectively identifying children at higher risk for elevated PbB. METHODS: We tested for PbB 3630 children aged 6 to 72 months attending SCC public outpatient clinics between August 8, 1991, and September 1, 1992. We then conducted two matched case-control studies. Five local risk-factor questions were combined with the CDC's five-question lead poisoning questionnaire, and from May 1, 1993, to June 30, 1993, we conducted risk assessments on 247 children tested for PbB. RESULTS: Two hundred twenty-two of 3630 children (6.1%) had a PbB of 10 micrograms/dL or greater. Thirty-nine (1.1%) had a PbB at least 20 micrograms/dL. Seventy-nine percent of the children screened and 91.0% of the children with PbB at least 10 micrograms/dL were Hispanic. Twenty percent of Mexican-born Hispanic children had a PbB of 10 micrograms/dL or greater, versus 7% of U.S.-born Hispanic children. Several factors were associated with elevated PbB among Hispanic children. For identifying children with a PbB of at least 10 micrograms/dL, the sensitivity and predictive value negative for the CDC's "high risk" definition were 30% and 93%, respectively, whereas for the SCC population-specific high-risk definition, the sensitivity was 90% and the predictive value negative was 98%. CONCLUSIONS: Hispanic children attending SCC public clinics have risk factors for elevated PbB that were not included in the CDC's lead poisoning questionnaire. Methods for prioritizing the frequency of lead screening may be improved by combining the CDC's questions with a population-specific risk assessment.

Preventing neonatal group B streptococcal disease: cost-effectiveness in a health maintenance organization and the impact of delayed hospital discharge for newborns who received intrapartum antibiotics.

OBJECTIVES: To estimate the cost and health benefits of implementing a risk factor-based prevention strategy for early-onset neonatal group B streptococcal (GBS) disease, using baseline assumptions and costs from a health maintenance organization. With the risk factor-based strategy, intrapartum antibiotics (IPAs) would be provided to women with fever, prolonged rupture of membranes, or preterm labor. A second objective was to determine the impact of an increased length of stay for well term infants with mothers who received IPAs. METHODS: We used decision analysis to compare the costs and benefits of the prevention strategy with usual obstetric practice for a cohort of 100 000 women and their newborn infants. We derived baseline values from a previous study based on chart review and automated cost data from a health maintenance organization in Northern California. In sensitivity analyses, we varied baseline assumptions, including additional costs for observing well term infants who received IPAs. RESULTS: If adherence to guidelines were 100%, 17% of mothers would receive IPAs at a cost of $490,000; $1.6 million would be saved by preventing 66 GBS cases (64% reduction). The net savings would be $1.1 million and 61 life-years. The net cost is sensitive to the cost of caring for well infants who received IPAs. If each term infant of a mother who received IPAs had 1 more day of observation than other term infants, there would be a net cost of $8.1 million; the cost per GBS case prevented would be $120,000 and the cost per life-year saved would be $130,000. CONCLUSIONS: Implementation in a health maintenance organization of a risk factor-based strategy to prevent neonatal GBS disease can prevent substantial disease and be cost saving. However, if the length of hospital stay were extended among well term infants whose mothers received IPAs, the strategy would be relatively costly compared with other medical interventions.

Multistate case-control study of maternal risk factors for neonatal group B streptococcal disease. The Active Surveillance Study Group.

Risk factors for early onset disease (EOD) caused by Group B streptococci (GBS) that are the foundation of prevention guidelines were identified in studies conducted in a few hospital centers. We investigated cases of EOD identified through laboratory-based active surveillance during 1991 and 1992 in a multistate population of 17 million. Ninety-nine cases were compared with 253 controls matched for hospital, date of birth and birth weight. Prematurity (< 37 weeks of gestation) was present in 28% of cases; 53% of case mothers had rupture of membranes > 12 hours; and 48% reported intrapartum fever. The incidence of EOD in each surveillance area was higher among blacks. By multivariate analysis, case mothers were more likely than controls to have rupture of membranes before labor onset (adjusted odds ratio 8.7, P < 0.001), intrapartum fever (adjusted odds ratio 11.9, P < 0.001), and history of urinary infection during pregnancy (adjusted odds ratio 4.3, P < 0.05). Young maternal age was also associated with risk of disease. Three-fourths of case mothers had intrapartum fever, < 37 weeks of gestation and/or prolonged rupture of membranes, indicators previously used to select high risk women for intrapartum chemoprophylaxis. Our findings extend data from single hospitals and suggest prenatal screening and selective intrapartum chemoprophylaxis of high-risk mothers could potentially prevent the majority of EOD in the United States.

Carriage of Haemophilus influenzae type b in children after widespread vaccination with conjugate Haemophilus influenzae type b vaccines.

Rates of invasive Haemophilus influenzae type b (Hib) disease in children decreased very rapidly after licensure of Hib conjugate vaccines. A role for a vaccine-related reduction in nasopharyngeal carriage of Hib has been suggested. We studied oropharyngeal carriage of Hib and vaccination rates in a population of 2- to 5-year-old children in metropolitan Atlanta. Among 584 children 75% were vaccinated with an Hib conjugate vaccine, 17% had not been vaccinated and 8% had no vaccination records available. Forty-one percent of the children were colonized with H. influenzae. One child was colonized with Hib. Hib carriage (0.17%; upper 95% confidence interval boundary, 0.97%) was substantially lower than the estimates of Hib carriage from prior studies of children who had not received Hib conjugate vaccines. Our data are consistent with a decline in Hib carriage induced by widespread use of conjugate Hib vaccines, which may have contributed to the decline of Hib disease in United States children.

Neonatal group B streptococcal infection in a managed care population. Perinatal Group B Streptococcal Infection Study Group.

OBJECTIVE: In a health maintenance organization population, we determined the incidence of early-onset (at less than or equal to 7 days) neonatal group B streptococcal (GBS) disease, the sensitivity and prevalence of labor risk factors, the adherence to a protocol for intrapartum antibiotics, and the costs for care of and outcomes of affected infants. METHODS: Mothers and infants at four health maintenance organization hospitals in northern California in 1989 to 1995 were studied retrospectively using computerized databases and chart review. In 1994, two of the four hospitals had adopted protocols similar to the ACOG recommendations for intrapartum antibiotics for women with labor risk factors (preterm, temperature 100.4F or higher, or rupture of membranes (ROM) 18 hours or more). RESULTS: Among the 79,940 live births, the incidence of early-onset neonatal GBS infection was higher among preterm than among term infants (3.1 compared with 0.9 per 1000). Before protocol adoption, 68% of 65 infants with GBS had mothers with labor risk factors. Approximately 18% of all mothers had labor risk factors: 7.7% had preterm delivery, and 10.6% had term delivery with fever and/or ROM 18 hours or more. At the two hospitals that adopted GBS protocols, GBS incidence was reduced from 1.3 per 1000 in the preprotocol period to 0.8 per 1000 in the postprotocol period (P=.08). Six cases of neonatal GBS occurred after protocol adoption. Of these, four were not preventable under the protocol and two might have been preventable if protocol had been followed. Three of the 19 preterm infants with group B streptococcal disease died. CONCLUSION: Risk factor-based protocols hold some promise to reduce GBS disease, but clinical strategies to promote protocol adherence are needed.

Yield of source-case and contact investigations in identifying previously undiagnosed childhood tuberculosis.

OBJECTIVE: To determine the extent to which source-case investigations, in which a child was the index tuberculosis (TB) case, and contact investigations of adult pulmonary cases, identified children and adults with previously undiagnosed TB or latent tuberculosis infection (LTBI). METHODS: We reviewed records of 111 source-case investigations and 38 contact investigations involving 164 TB cases among children <5 years of age from eight California health jurisdictions with a case rate greater than the state average for this age group (9.6/100000). RESULTS: In source-case investigations, 141 children <5 years and 113 children 5-14 years of age were evaluated for TB disease and LTBI. Fourteen previously undiagnosed TB cases were found, including seven children <5 years of age. Source-case investigations also identified persons who might benefit from treatment for LTBI (45% had a positive tuberculin reaction). In contact investigations of adult TB cases, 202 children <5 years and 122 children 5-14 years of age were evaluated. In addition to 46 children with TB <5 years of age, the basis on which these contact investigations were selected for study, four children 5-14 years of age and 10 adults were found to have TB disease. A high percentage (41%) of contacts with a positive tuberculin reaction was found, especially among household contacts. CONCLUSIONS: Source-case investigations and contact investigations are effective for finding previously undiagnosed cases of TB. They are also useful for identifying children and adults who would possibly benefit from treatment for LTBI. Earlier detection and treatment of adults with TB could interrupt transmission and be a step toward eliminating childhood TB.

B notifications and the detection of tuberculosis among foreign-born recent arrivals in California.

OBJECTIVE: To evaluate the effectiveness and limitations of the B notification program for detecting tuberculosis among recent foreign-born arrivals in California. DESIGN: Retrospective cohort study. All foreign-born visa holders with a B notification who arrived in California from January 1992 through September 1995 (n = 27 412) were matched with a listing of foreign-born persons who arrived in the US during the same time period and who were reported to have active tuberculosis in California within one year of their arrival from January 1992 through September 1996 (n = 2547). RESULTS: Overall, 3.5% (95% confidence interval 3.3%, 3.8%) of all persons with a B notification were reported to have active tuberculosis within a year of arrival. Recent arrivals with a B notification and tuberculosis accounted for 38% of all foreign-born cases of tuberculosis reported within one year of arrival. Compared to recent arrivals without a B notification, those with a B notification were more likely to have pulmonary tuberculosis, less likely to have smear-positive pulmonary disease and reported with tuberculosis sooner after their arrival in the US. The B notification program was not able to identify 87% of the smear-positive pulmonary tuberculosis cases in adults, and did not identify 99% of these highly infectious cases among Latin Americans. CONCLUSIONS: Although the evaluation of persons who enter the US with B notifications has a high yield for identifying active tuberculosis cases, it was not able to identify the majority of recent arrivals with the most infectious form of tuberculosis.

High incidence of extra-intestinal infections in a Salmonella Havana outbreak associated with alfalfa sprouts.

OBJECTIVE: To determine a vehicle and point source for an outbreak of Salmonella Havana. METHODS: The authors conducted a case-control study and traceback investigation of 14 residents of California and four from Arizona with onsets of illness from Apr 15, 1998, to June 15, 1998, and Salmonella Havana infections with identical PFGE patterns. RESULTS: Seventeen of 18 patients were women. Seventeen were adults 20-89 years of age. Nine (50%) had diarrheal illness, 6 (33%) had urinary tract infections, 2 (11%) had sepsis, and one had an infected surgical wound after appendectomy. Four patients were hospitalized, and one died. Eating alfalfa sprouts was associated with S. Havana infection (OR = 10.0; 95% confidence interval 1.2, 83.1; P = 0.01). CONCLUSIONS: This outbreak resulted in a high incidence of extra-intestinal infections, especially urinary tract infections, and high morbidity. Raw alfalfa sprouts, often considered a safe "heath food," can be a source of serious foodborne disease outbreaks.

Viral meningitis in child care center staff and parents: an outbreak of echovirus 30 infections.

OBJECTIVE: A report of five cases of viral meningitis among adults with children enrolled in a child care center prompted an investigation of risk factors for viral transmission from children to adult household members. METHODS: To determine recent echovirus 30 (E30) infections, the authors conducted a serologic survey. To determine risk factors for infection among adult household members, they conducted a retrospective cohort study using written questionnaires. RESULTS: Recent E30 infections were found in 84% of children tested, 57% of adult household members tested, and 47% of staff members tested. Infected adults were more likely than infected children to have clinical meningitis. Among adult household members, changing diapers was a risk factor for recent infection. Women who changed > or = 90 diapers per month had a higher infection rate than women who changed fewer diapers; in contrast, men who changed > or = 90 diapers per month had a lower infection rate than men who changed fewer diapers. Handwashing was protective: there was a negative correlation between handwashing after diaper changes and E30 infection among adults with infected children in diapers. CONCLUSIONS: Because child care centers can be a source of enteroviral infections among adult household members, adults with viral meningitis should be questioned about their children's day care or preschool attendance. The importance of handwashing should be stressed to adults with children in day care.

Alfalfa sprouts and Salmonella Kottbus infection: a multistate outbreak following inadequate seed disinfection with heat and chlorine.

Raw sprouts have been implicated in a number of foodborne disease outbreaks. Because contaminated seeds are usually responsible, many sprout producers attempt to disinfect seeds before germination and detect sprout contamination during production. In March 2001, we detected an increased number of Salmonella serotype Kottbus isolates in California. Overall, we identified 31 cases from three western states. To identify the cause, we conducted a case-control study with the first 10 identified case-patients matched to 20 controls by age, sex, and residential area. Our case-control study found illness to be statistically associated with alfalfa sprout consumption. The traceback investigation implicated a single sprouter, where environmental studies yielded Salmonella Kottbus from ungerminated seeds and floor drains within the production facility. Pulsed-field gel electrophoresis patterns of all patient, seed, and floor drain Salmonella Kottbus isolates were indistinguishable. Most implicated sprouts were from seeds that underwent heat treatment and soaking with a 2,000-ppm sodium hypochlorite solution rather than the Food and Drug Administration (FDA)-recommended 20,000-ppm calcium hypochlorite soak. Other implicated seeds had been soaked in a calcium hypochlorite solution that, when tested, measured only 11,000 ppm. The outbreak might have been averted when screening tests of sprout irrigation water detected Salmonella in January; however, confirmatory testing of these samples was negative (but testing improperly utilized refrigerated irrigation water). Producers should use the enrichment broth of positive screening samples, not refrigerated irrigation water, for confirmatory testing. Until other effective disinfection technologies are developed, producers should adhere to FDA recommendations for sprout seed disinfection.

Multistate outbreak of multidrug-resistant Salmonella newport infections associated with ground beef, October to December 2007.

In late October 2007, an outbreak of multidrug-resistant Salmonella Newport infections affected 42 case patients in California, Arizona, Idaho, and Nevada. A case-control study implicated ground beef from one chain store. Despite detailed ground beef purchase histories--including shopper card information for several case patients--traceback efforts by both the U.S. Department of Agriculture, Food Safety and Inspection Service and the California Department of Public Health were unable to identify the source of contamination. Case patients consumed multiple types of ground beef products purchased at numerous chain store A retail locations. These stores had received beef products for grinding from multiple beef slaughter-processing establishments. Detailed retail grinding logs and grinding policies that prevent cross-contamination between batches of ground beef products are crucial in the identification of contaminated beef products associated with foodborne illness.

Salmonella infections associated with mung bean sprouts: epidemiological and environmental investigations.

We investigated an outbreak of Salmonella Enteritidis (SE) infections linked to raw mung bean sprouts in 2000 with two case-control studies and reviewed six similar outbreaks that occurred in 2000-2002. All outbreaks were due to unusual phage types (PT) of SE and occurred in the United States (PT 33, 1, and 913), Canada (PT 11b and 913), and The Netherlands (PT 4b). PT 33 was in the spent irrigation water and a drain from one sprout grower. None of the growers disinfected seeds at recommended concentrations. Only two growers tested spent irrigation water; neither discarded the implicated seed lots after receiving a report of Salmonella contamination. We found no difference in the growth of SE and Salmonella Newport on mung beans. Mung bean sprout growers should disinfect seeds, test spent irrigation water, and discontinue the use of implicated seed lots when pathogens are found. Laboratories should report confirmed positive Salmonella results from sprout growers to public health authorities.

Risk factors for sporadic Shiga toxin-producing Escherichia coli O157 infections in FoodNet sites, 1999-2000.

To monitor risk factors for illness, we conducted a case-control study of sporadic Shiga toxin-producing Escherichia coli O157 (STEC O157) infections in 1999-2000. Laboratory-confirmed cases of STEC O157 infection were identified through active laboratory surveillance in all or part of seven states. Patients and age-matched controls were interviewed by telephone using a standard questionnaire. Information was collected on demographics, clinical illness, and exposures to food, water, and animals in the 7 days before the patient's illness onset. During the 12-month study, 283 patients and 534 controls were enrolled. STEC O157 infection was associated with eating pink hamburgers, drinking untreated surface water, and contact with cattle. Eating produce was inversely associated with infection. Direct or indirect contact with cattle waste continues to be a leading identified source of sporadic STEC O157 infections.

The impact of health communication and enhanced laboratory-based surveillance on detection of cyclosporiasis outbreaks in California.

We investigated the timing of diagnosis, influence of media information on testing for Cyclospora, and the method used to identify cases during eight cyclosporiasis outbreaks in California in spring of 1997. We found that Internet information, media reports, and enhanced laboratory surveillance improved detection of these outbreaks.