Publications (39)362.45 Total impact
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Article: Salmonella infections associated with mung bean sprouts: epidemiological and environmental investigations.
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ABSTRACT: 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.Epidemiology and Infection 03/2008; 137(3):357-66. · 2.84 Impact Factor -
Article: Outbreak of cryptosporidiosis at a California waterpark: employee and patron roles and the long road towards prevention.
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ABSTRACT: In August-September 2004, a cryptosporidiosis outbreak affected >250 persons who visited a California waterpark. Employees and patrons of the waterpark were affected, and three employees and 16 patrons admitted to going into recreational water while ill with diarrhoea. The median illness onset date for waterpark employees was 8 days earlier than that for patrons. A case-control study determined that getting water in one's mouth on the waterpark's waterslides was associated with illness (adjusted odds ratio 7.4, 95% confidence interval 1.7-32.2). Laboratory studies identified Cryptosporidium oocysts in sand and backwash from the waterslides' filter, and environmental investigations uncovered inadequate water-quality record keeping and a design flaw in one of the filtration systems. Occurring more than a decade after the first reported outbreaks of cryptosporidiosis in swimming pools, this outbreak demonstrates that messages about healthy swimming practices have not been adopted by pool operators and the public.Epidemiology and Infection 03/2007; 135(2):302-10. · 2.84 Impact Factor -
Article: Outbreak of Serratia marcescens infections following injection of betamethasone compounded at a community pharmacy.
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ABSTRACT: In June 2001, following the report of 4 patients with Serratia marcescens meningitis who received epidural injections of betamethasone compounded at a community pharmacy, we initiated an outbreak investigation. All patients who received injections of betamethasone from the production lot common to the 4 patients were evaluated. A case patient was defined as a patient who received compounded betamethasone and had S. marcescens isolated from a sterile site or clinical and laboratory evidence of infection. We cultured all recovered betamethasone, environmental specimens from the pharmacy, and medications recovered from an ambulatory surgery center. The California Board of Pharmacy reviewed the procedures used to prepare the betamethasone. We identified 11 patients with culture-confirmed S. marcescens (8 patients) or clinical infection (3 patients) following injection of compounded betamethasone from 25 May through 31 May 2001. Case patients had meningitis (5 patients, with 3 deaths), epidural abscesses (5 patients), or an infected hip (1 patient). S. marcescens was isolated from 35 (69%) of 51 betamethasone vials recovered, from pharmacy specimens of 1% carboxymethylcellulose stock solution, from pharmacy surfaces, and from multiple parenteral materials used at the ambulatory surgery center. Pulsed-field gel electrophoresis patterns of S. marcescens isolates of representative specimens from patients, the betamethasone, the pharmacy, and the ambulatory surgery center were identical. Deficient practices in compounding of betamethasone included inadequate autoclaving temperatures and failure to perform terminal sterilization. This outbreak of serious S. marcescens infection followed improper compounding of betamethasone in a community pharmacy. Enforceable national standards for pharmaceutical compounding are needed to reduce the risk of such outbreaks.Clinical Infectious Diseases 11/2006; 43(7):831-7. · 9.15 Impact Factor -
Article: A multi-state outbreak of Salmonella serotype Thompson infection from commercially distributed bread contaminated by an ill food handler.
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ABSTRACT: Foodborne transmission is estimated to account for 95% of non-typhoidal Salmonella infections reported in the United States; however, outbreaks of salmonellosis are rarely traced to food handlers. In August 2000, an increase in Salmonella serotype Thompson infection was noted in Southern California; most of the cases reported eating at a restaurant chain (Chain A) before illness onset. A case-control study implicated the consumption of burgers at Chain A restaurants. The earliest onset of illness was in a burger bun packer at Bakery B who had not eaten at Chain A but had worked while ill. Bakery B supplied burger buns to some Chain A restaurants in Southern California and Arizona. This outbreak is notable for implicating a food handler as the source of food contamination and for involving bread, a very unusual outbreak vehicle for Salmonella . Inadequate food-handler training as well as delayed reporting to the health department contributed to this outbreak.Epidemiology and Infection 11/2005; 133(5):823-8. · 2.84 Impact Factor -
Article: A large outbreak of scombroid fish poisoning associated with eating escolar fish (Lepidocybium flavobrunneum).
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ABSTRACT: In August 2003, an outbreak of scombroid fish poisoning occurred at a retreat centre in California, USA. In a retrospective cohort study, 42 (75%) of the 56 dinner attendees who ate escolar fish (Lepidocybium flavobrunneum) met the case definition. Individuals who ate at least 2 oz of fish were 1.5 times more likely to develop symptoms than those who ate less (relative risk 1.5, 95% confidence interval 0.9-2.6), and to develop more symptoms (median 7 vs. 3 symptoms, P = 0.03). Patients who took medicine had a longer duration of symptoms than those who did not (median 4 vs. 1.5 h, P = 0.05), and experienced a greater number of symptoms (median 8 vs. 3 symptoms, P = 0.0002). Samples of fish contained markedly elevated histamine levels (from 2000 to 3800 ppm). This is one of the largest reported outbreaks of scombroid fish poisoning in the United States and was associated with a rare vehicle for scombroid fish poisoning, escolar.Epidemiology and Infection 03/2005; 133(1):29-33. · 2.84 Impact Factor -
Article: Epidemic and sporadic cases of nontuberculous mycobacterial keratitis associated with laser in situ keratomileusis.
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ABSTRACT: To report national case-finding results for nontuberculous mycobacterial keratitis and describe its association with laser in situ keratomileusis (LASIK). Enhanced passive disease reporting. In April 2001, we investigated a California cluster of Mycobacterium chelonae keratitis associated with hyperopic LASIK using a contact lens mask. To identify other possibly related cases, the American Academy of Ophthalmology e-mailed its members asking them to report recent cases of nontuberculous mycobacterial keratitis to the Centers for Disease Control and Prevention. Forty-three additional cases of keratitis were reported (onsets between August 2000 and June 2001). Of these, 31 occurred as part of two unrelated LASIK-associated outbreaks. The 12 other reported cases occurred in sporadic fashion. Of the latter cases, 4 were associated with LASIK surgery. None of the reported cases were related to the M. chelonae cluster in California. Laser in situ keratomileusis-associated keratitis with nontuberculous mycobacteria may be more common than previously known.American Journal of Ophthalmology 03/2003; 135(2):223-4. · 4.22 Impact Factor -
Article: Alfalfa sprouts and Salmonella Kottbus infection: a multistate outbreak following inadequate seed disinfection with heat and chlorine.
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ABSTRACT: 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.Journal of food protection 02/2003; 66(1):13-7. · 1.94 Impact Factor -
Article: Escherichia coli O157 and Salmonella infections associated with sprouts in California, 1996-1998.
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ABSTRACT: In California, from 1996 through 1998, more than 50% of multicounty outbreaks with confirmed food vehicles were related to alfalfa or clover sprouts. To summarize investigations of sprout-associated outbreaks. Matched case-control studies. California. Outbreak-associated patients and matched population controls. Matched odds ratios and 95% CIs; traceback and environmental investigations of sprout and seed growers; and pulsed-field gel electrophoresis of isolates from patients, sprouts, and seeds. Five sprout-associated outbreaks of salmonellosis and one outbreak of infection with nonmotile Shiga toxin-producing Escherichia coli O157 occurred. Six hundred patients had culture-confirmed disease, and two died. It is estimated that these outbreaks caused 22 800 cases of gastrointestinal illness or urinary tract infection. In the case-control studies, odds ratios for the association between illness and alfalfa sprout consumption ranged from 5.0 to infinity (all were statistically significant). Three sprout growers were implicated, and each was associated with two outbreaks. Outbreak strains of Salmonella were isolated from sprouts supplied by two sprout growers and from seeds used by the third sprout grower. As currently produced, sprouts can be a hazardous food. Seeds can be contaminated before sprouting, and no method can eliminate all pathogens from seeds. Seed and sprout growers should implement measures to decrease contamination. The general public should recognize the risks of eating sprouts, and populations at high risk for complications from salmonellosis or E. coli O157 infection should avoid sprout consumption.Annals of internal medicine 09/2001; 135(4):239-47. · 16.73 Impact Factor -
Article: An outbreak of Salmonella serotype Thompson associated with fresh cilantro.
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ABSTRACT: An outbreak of Salmonella serotype Thompson in California was identified through laboratory-based surveillance and investigated with case-control, traceback, and laboratory studies. There were 35 "sporadic" cases and a restaurant-associated outbreak of 41 cases with onset between 6 March and 31 March 1999. Three case patients were hospitalized. A case-control study found a significant association between illness and eating cilantro at a restaurant (63% of case patients vs. 34% of control subjects; odds ratio, 3.5; 95% confidence interval, 1.1-11.4). Although common distributors of cilantro were identified, inadequate records prohibited the identification of a single farm supplying cilantro. At room temperature, Salmonella Thompson grew more rapidly and to a higher concentration on chopped cilantro, compared with whole-leaf cilantro. Freshly made salsa (pH 3.4) supported growth of Salmonella Thompson. Cilantro should be served promptly after chopping. Accurate records of the distribution of produce should be available, and bacterial contamination of produce should be prevented in retail and wholesale establishments, in packing sheds, and on farms.The Journal of Infectious Diseases 04/2001; 183(6):984-7. · 6.41 Impact Factor -
Article: Risk factors for severe pulmonary and disseminated coccidioidomycosis: Kern County, California, 1995-1996.
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ABSTRACT: Surveillance for coccidioidomycosis (CM) and a case-control study for risk factors among adults were conducted in Kern County, California. From January 1995 through December 1996, 905 cases of CM were identified, for an annual incidence of 86 cases per 100,000 population. A total of 380 adults were enrolled in the case-control study: 77 had severe pulmonary disease, 33 had disseminated disease, and 270 control patients had mild disease. Independent risk factors for severe pulmonary disease included diabetes, recent history of cigarette smoking, income of < $15,000 per year, and older age. Oral antifungal therapy before hospitalization was associated with a reduced risk of CM pneumonia. Risk factors for disseminated disease were black race, income of < $15,000 per year, and pregnancy. Early treatment of CM with oral antifungal agents may prevent severe pulmonary disease in groups considered to be at high risk, such as elderly individuals, persons with diabetes, and smokers. Persons at risk for severe CM may benefit from vaccination once an effective CM vaccine is available.Clinical Infectious Diseases 04/2001; 32(5):708-15. · 9.15 Impact Factor -
Article: Wound botulism in California, 1951-1998: recent epidemic in heroin injectors.
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ABSTRACT: California has reported most of the world's wound botulism (WB) cases and nearly three-fourths of the cases reported in the United States. We reviewed the clinical, epidemiologic, and laboratory features of WB. From the first case in 1951, through 1998, a total of 127 cases were identified-93 in the last 5 years. The dramatic increase has been due to an epidemic (of WB) in people who inject black tar heroin. Whereas early cases of WB occurred after gross trauma, all but 1 of the last 102 cases occurred in drug users, primarily those who inject drugs subcutaneously ("skin poppers"). Cases are occurring disproportionately in Hispanics and women. Misdiagnosis and diagnostic delays of up to 64 days have occurred. This unprecedented, ongoing epidemic is now being reported in other states. We discuss the clinical and laboratory features that distinguish botulism from conditions that can mimic it, the relative yield of various diagnostic laboratory tests for botulism, and its treatment.Clinical Infectious Diseases 11/2000; 31(4):1018-24. · 9.15 Impact Factor -
Article: Using towels and soap in steam baths could reduce infection.
Western Journal of Medicine 05/2000; 172(4):239. -
Article: An outbreak of Salmonella serogroup Saphra due to cantaloupes from Mexico.
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ABSTRACT: An outbreak of Salmonella serogroup Saphra (S. saphra) infections was studied by laboratory-based surveillance, case-control and trace-back studies, and a survey of cantaloupe preparation practices. Twenty-four patients with S. saphra infections had illness onsets between 23 February and 15 May 1997; 75% were </=6 years old; 23% were hospitalized. Case patients were more likely than controls to have consumed cantaloupe (88% vs. 45%; matched odds ratio [MOR], 15. 5; 95% confidence interval [CI], 1.7-139) and precut cantaloupe (59% vs. 19%; MOR, 14.5; 95% CI, 1.6-128). The trace-back study identified 1 growing region in Mexico as the source of cantaloupes for 95% of the patients who ate cantaloupes. Only 17% of case patients washed cantaloupes before cutting them. This outbreak is another example of gastrointestinal disease in the United States associated with imported contaminated produce. Consumers and retailers should wash cantaloupes before cutting them; there should be international efforts to ensure food safety.The Journal of Infectious Diseases 10/1999; 180(4):1361-4. · 6.41 Impact Factor -
Article: Mushroom poisoning due to amatoxin. Northern California, Winter 1996-1997.
Western Journal of Medicine 01/1999; 169(6):380-4. -
Article: Salmonella enteritidis infections from shell eggs: outbreaks in California.
Western Journal of Medicine 12/1998; 169(5):299-303. -
Article: Wound botulism associated with black tar heroin among injecting drug users.
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ABSTRACT: Wound botulism (WB) is a potentially lethal, descending, flaccid, paralysis that results when spores of Clostridium botulinum germinate in a wound and elaborate neurotoxin. Since 1988, California has experienced a dramatic increase in WB associated with injecting "black tar" heroin (BTH), a dark, tarry form of the drug. To identify risk factors for WB among injecting drug users (IDUs). Case-control study based on data from in-person and telephone interviews. Case patients (n=26) were IDUs who developed WB from January 1994 through February 1996. Controls (n=110) were IDUs newly enrolled in methadone detoxification programs in 4 counties. Factors associated with the development of WB. Among the 26 patients, the median age was 41.5 years, 15 (58%) were women, 14 (54%) were non-Hispanic white, 11 (42%) were Hispanic, and none were positive for the human immunodeficiency virus. Nearly all participants (96% of patients and 97% of controls) injected BTH, and the mean cumulative dose of BTH used per month was similar for patients and controls (27 g and 31 g, respectively; P=.6). Patients were more likely than controls to inject drugs subcutaneously or intramuscularly (92% vs 44%, P<.001) and used this route of drug administration more times per month (mean, 67 vs 24, P<.001), with a greater cumulative monthly dose of BTH (22.3 g vs 6.3 g, P<.001). A dose-response relationship was observed between the monthly cumulative dose of BTH injected subcutaneously or intramuscularly and the development of WB (chi2 for linear trend, 26.5; P<.001). In the final regression model, subcutaneous or intramuscular injection of BTH was the only behavior associated with WB among IDUs (odds ratio, 13.7; 95% confidence interval, 3.0-63.0). The risk for development of WB was not affected by cleaning the skin, cleaning injection paraphernalia, or sharing needles. Injection of BTH intramuscularly or subcutaneously is the primary risk factor for the development of WB. Physicians in the western United States, where BTH is widely used, should be aware of the potential for WB to occur among IDUs.JAMA The Journal of the American Medical Association 03/1998; 279(11):859-63. · 30.03 Impact Factor -
Article: Enhanced control of an outbreak of Mycoplasma pneumoniae pneumonia with azithromycin prophylaxis.
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ABSTRACT: There are currently no recommended epidemic-control measures for Mycoplasma pneumoniae pneumonia outbreaks in closed communities. Previous studies have suggested the usefulness of chemoprophylaxis administered to close contacts of case-patients. To evaluate the effectiveness of various epidemic-control measures during an institutional outbreak, an observational study was undertaken during a very large outbreak of M. pneumoniae pneumonia at a facility for developmentally disabled residents (n = 142 cases). Control measures evaluated included no control, standard epidemic-control measures, and targeted azithromycin prophylaxis (500 mg on day 1, 250 mg/day on days 2-5) plus standard epidemic-control measures. The combined use of azithromycin prophylaxis and standard epidemic-control measures was associated with a significant reduction in the secondary attack rate. This study suggests that the addition of antibiotic prophylaxis to standard epidemic-control measures can be useful during institutional outbreaks of M. pneumoniae pneumonia.The Journal of Infectious Diseases 02/1998; 177(1):161-6. · 6.41 Impact Factor -
Article: Postoperative Serratia marcescens wound infections traced to an out-of-hospital source.
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ABSTRACT: From 25 August to 28 September 1994, 7 cardiovascular surgery (CVS) patients at a California hospital acquired postoperative Serratia marcescens infections, and 1 died. To identify the outbreak source, a cohort study was done of all 55 adults who underwent CVS at the hospital during the outbreak. Specimens from the hospital environment and from hands of selected staff were cultured. S. marcescens isolates were compared using restriction-endonuclease analysis and pulsed-field gel electrophoresis. Several risk factors for S. marcescens infection were identified, but hospital and hand cultures were negative. In October, a patient exposed to scrub nurse A (who wore artificial fingernails) and to another nurse-but not to other identified risk factors-became infected with the outbreak strain. Subsequent cultures from nurse A's home identified the strain in a jar of exfoliant cream. Removal of the cream ended the outbreak. S. marcescens does not normally colonize human skin, but artificial nails may have facilitated transmission via nurse A's hands.The Journal of Infectious Diseases 05/1997; 175(4):992-5. · 6.41 Impact Factor -
Article: A coccidioidomycosis outbreak following the Northridge, Calif, earthquake.
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ABSTRACT: To describe a coccidioidomycosis outbreak in Ventura County following the January 1994 earthquake, centered in Northridge, Calif, and to identify factors that increased the risk for acquiring acute coccidioidomycosis infection. Epidemic investigation, population-based skin test survey, and case-control study. Ventura County, California. In Ventura County, between January 24 and March 15, 1994, 203 outbreak-associated coccidioidomycosis cases, including 3 fatalities, were identified (attack rate [AR], 30 cases per 100,000 population). The majority of cases (56%) and the highest AR (114 per 100,000 population) occurred in the town of Simi Valley, a community located at the base of a mountain range that experienced numerous landslides associated with the earthquake. Disease onset for cases peaked 2 weeks after the earthquake. The AR was 2.8 times greater for persons 40 years of age and older than for younger persons (relative risk, 2.8; 95% confidence interval [CI], 2.1-3.7; P<.001). Environmental data indicated that large dust clouds, generated by landslides following the earthquake and strong aftershocks in the Santa Susana Mountains north of Simi Valley, were dispersed into nearby valleys by northeast winds. Simi Valley case-control study data indicated that physically being in a dust cloud (odds ratio, 3.0; 95% CI, 1.6-5.4; P<.001) and time spent in a dust cloud (P<.001) significantly increased the risk for being diagnosed with acute coccidioidomycosis. Both the location and timing of cases strongly suggest that the coccidioidomycosis outbreak in Ventura County was caused when arthrospores were spread in dust clouds generated by the earthquake. This is the first report of a coccidioidomycosis outbreak following an earthquake. Public and physician awareness, especially in endemic areas following similar dust cloud-generating events, may result in prevention and early recognition of acute coccidioidomycosis.JAMA The Journal of the American Medical Association 04/1997; 277(11):904-8. · 30.03 Impact Factor -
Article: Cholera from raw seaweed transported from the Philippines to California.
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ABSTRACT: In March 1994, a California woman without any recent travel developed acute, profuse, watery diarrhea. Her astute physician diagnosed cholera after ordering the appropriate stool culture, and the patient improved on an oral antibiotic. Epidemiologic investigation implicated seaweed from the Philippines that was transported by a friend to California and subsequently eaten raw as the vehicle of infection.Journal of Clinical Microbiology 02/1997; 35(1):284-5. · 4.15 Impact Factor
Top co-authors
Top Journals
Institutions
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2008
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California Department of Public Health
California City, CA, USA
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1997–2007
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Centers for Disease Control and Prevention
- National Center for Emerging and Zoonotic Infectious Diseases
Atlanta, MI, USA -
University of California, Berkeley
- School of Public Health
Berkeley, MO, USA
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2005
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University of Maryland, College Park
College Park, MD, USA
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1999–2005
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State of California
California City, CA, USA -
California Department of Health Care Services
Sacramento, CA, USA
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