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Frequency of Salmonella typhimurium the year after a massive outbreak.

In 1985, Illinois experienced a large milkborne outbreak of Salmonella typhimurium with over 16,000 cases. During this year, 49.4% of United States and 86.4% of Illinois salmonellae were S. typhimurium. In 1986, 1133 microbiologically confirmed and serotyped cases of salmonellosis were reported in the City of Chicago, comprising 37% of the 3034 cases reported for the State of Illinois. The most frequent serotypes were S. typhimurium (21.3%), Salmonella heidelberg (18.2%), Salmonella enteritidis (10.7%), and Salmonella braenderup (7.7%), similar to the state as a whole. Nationally, excluding Illinois, the most frequent serotypes in 1986 were S. typhimurium (26.1%), S. enteritidis (14.7%), and S. heidelberg (13.0%). S. braenderup comprised 0.9% of the non-Illinois total. Regional variations in the epidemiology of salmonellae are probable and may reflect detected or undetected outbreaks. Within a year of the nation's largest Salmonella outbreak, there was no trace of any effect on the frequency of isolation of Salmonella spp.

Chicago↗

The utility of restriction endonuclease analysis and phage typing in the epidemiologic investigation of a Staphylococcus aureus outbreak in a neonatal nursery.

Outbreaks of Staphylococcus aureus infections in neonatal units require prompt investigation and implementation of control measures. From January to March 1990, a marked increase in the number of S. aureus infections was observed in a neonatal nursery. Twenty-seven S. aureus isolates from 23 patients were analyzed by phage typing and restriction endonuclease analysis (REA). Only nine strains were differentiated by phage type. However, REA with HindIII, CfoI, and ClaI differentiated 20 strains. The REA results indicated that the outbreak was due to several different S. aureus strains and did not represent transmission of a single epidemic strain. REA may enable more accurate determination of the presence or absence of an epidemic strain during an outbreak than would traditional methods such as phage typing.

Bacteriophage Typing↗

A large Q fever outbreak in the West Midlands: clinical aspects.

In the spring of 1989 the largest outbreak of acute Q fever recorded in the United Kingdom occurred in Solihull and surrounding areas of the West Midlands. The diagnosis was confirmed in 147 people, mainly males of working age. Windborne spread from farmland to the south of the urban area was the most likely route of infection. Fever was the commonest symptom, seen in 101/102 (99%) cases, followed by weight loss reported by 83/101 (82%). Headache, often severe, was experienced by 69/101 (68%). The commonest respiratory symptom was breathlessness, 65/102 (64%), followed by cough, 52/102 (51%), and chest pain, 46/102 (45%). Neurological features, seen in 23% of cases, were more prominent in this outbreak than is commonly recognized. Persisting ill health 6 months following the acute episode not due to chronic Q fever was also a prominent feature of this largely urban outbreak.

Adolescent↗

Outbreak of Burkholderia cepacia bacteremia in immunocompetent children caused by contaminated nebulized sulbutamol in Saudi Arabia.

BACKGROUND: An outbreak of 5 inpatient and otherwise healthy children admitted for respiratory problems developed dry fever and cough after a few days of hospitalization. Burkhuldaria cepacia was isolated from their blood culture. The Infection Control Department (ICD) in the King Fahad Medical City (KFMC) detected and investigated the outbreak to identify the source of the organism and mode of transmission. METHODS: After the initial review of all the existing records in the KFMC, log book of the laboratory, and direct questioning of all physicians and revising the method of B cepacia identification in our laboratory, an observational study to identify any violation of infection control policy and a case-control study were designed to identify possible risk factors associated with the occurrence and transmission of the disease. RESULTS: A total of 7 healthy patients were reported to have B cepacia-positive blood culture, with 5 patients infected in the KFMC and 2 patients in their referring hospitals. We could isolate the same organism from sulbutamol solution 0.5% manufactured locally (Vintec). Among the risk factors studied, concomitant use of nebulized budesonide with sulbutamol (OR, 26; 95% CI: 1.31-1,187) was found to be 26 times more likely to be associated with infection and to be statistically significant; concomitant use of systemic hydrocortisone increased the risk of infection 4 times but, statistically, was not significant. No significant association was found with concomitant syncitial respiratory virus (RSV) infections or having chronic diseases. None of the affected patients were found to be immunocompromised. CONCLUSION: B cepacia can affect healthy children. Contaminated nebulized sulbutamol with B cepacia was the source of infection, and inhalation was the mode of transmission. Concomitant use of nebulized budesonide solution is a significant risk factor. The KFMC was the first health institution to diagnose this national outbreak.

Albuterol↗

Endemically acquired foodborne outbreak of enterotoxin-producing Escherichia coli serotype O169:H41.

PURPOSE: Enterotoxigenic Escherichia coli (ETEC) is traditionally recognized as a common cause of traveler's diarrhea, but is becoming a more frequent cause of foodborne disease outbreaks in the United States. It is important for public health practitioners and clinicians to be aware of ETEC as a domestic cause of gastroenteritis. We investigated a foodborne disease outbreak to understand the epidemiology of ETEC in this setting. METHODS: We conducted a cohort study of 63 employees of Company A. A case was defined as an employee who experienced diarrhea or vomiting or fever and cramps after eating a catered meal at Company A from August 14th-15th. A standardized questionnaire was administered to cases and controls. RESULTS: Of 63 employees, 36 met the case definition (Attack Rate = 57.1%). Diarrhea (94%) and cramps (74%) were common, whereas vomiting was not (3%). Mean duration of illness was 2.7 days. Coleslaw at the August 15th lunch was significantly associated with illness (Odds ratio = 4.4, 95% CI = 1.1-17). Stool specimens were positive for heat-stable enterotoxin-producing E. coli O169:H41. Contamination likely occurred at the point of service. CONCLUSIONS: This outbreak illustrates the changing epidemiology of enterotoxigenic E. coli and the importance for healthcare practitioners to consider ETEC as a potential cause of domestically acquired gastroenteritis.

Adult↗

Modeling a syphilis outbreak through space and time using the Bayesian maximum entropy approach.

PURPOSE: The aim of the study is to describe changes in the spatial distribution of syphilis before, during, and after an outbreak in Baltimore, MD, by using Bayesian maximum entropy (BME), a modern geostatistical technique for space-time analysis and mapping. METHODS: BME was used to conduct simple and composite space-time analyses of the density of syphilis infection based on primary, secondary and early latent syphilis cases reported to the Baltimore City Health Department between January 1, 1994, and December 31, 2002. RESULTS: Spatiotemporal covariance plots indicated that the distribution of the density of syphilis cases showed both spatial and temporal dependence. Temporally dependent disease maps suggested that syphilis increased within two geographic core areas of infection and spread outward. A new core area of infection was established to the northwest. As the outbreak waned, density diminished and receded in all core areas. Morbidity remained elevated in the two original central and new northwestern core areas after the outbreak. CONCLUSIONS: Density of syphilis infection was a simple informative measure easily compared across years. The BME approach was useful for quantitatively and qualitatively describing the spatial development and spread of syphilis. Our results are specific to Baltimore; however, the BME approach is generalizable to other settings and diseases.

Baltimore↗

[Pediatric features of an influenza A seasonal outbreak and its burden in pediatric emergency rooms and pediatric departments].

AIM OF THE STUDY: To describe epidemiological features of an outbreak of flu A in hospitalized children and to evaluate the flu's burden in pediatric and pediatric emergencies departments. POPULATION AND METHODS: Multicenter prospective study in 2 pediatric university hospitals, in Marseille, France. Nasal swabs for flu A were performed in all the febrile children admitted during winter 2003-2004. Pre and postoutbreak admissions in pediatric and pediatric emergencies departments were compared too. RESULTS: During the outbreak, 941 children were admitted and 605 were tested for flu A. Nasal swabs were positive in 111. Attack's rate was 11.8%. In these children, infants under 2 years were 66%. Respiratory forms were uncommon, although febrile seizures and digestive troubles were much frequent. The mean hospitalization duration was almost 4 days. Flu A outbreak finally increased the pediatric and pediatric emergencies departments rates of admission, of 48% and 37% respectively. CONCLUSION: Flu is frequently underestimated in children, especially in infants. Clinical forms are various. Child's vaccination is questionable in France.

Child, Preschool↗

Morphotypic and genotypic characterization of sequential Candida parapsilosis isolates from an outbreak in a pediatric intensive care unit.

Candidemia outbreaks that due to cross-infection are an emerging problem in hospitals. Typing of microorganisms is an essential tool for understanding the epidemiologic aspects of the infection. Techniques based on phenotypic characteristics are inexpensive and easy to perform but are limited by their lack of reproducibility. This study assessed the value of several phenotypic and genotypic techniques that are used in epidemiologic investigations of Candida parapsilosis in clinical practice and used a combination of these methods to analyze outbreak of C. parapsilosis candidemia. Random amplification of polymorphic DNA polymerase chain reaction with several primers was unsatisfactory because it lacked discriminatory power. By simplifying the reading of the morphotypes, we increased their reproducibility for each malt agar and 2,3,5-triphenyltetrazolium media (97% and 90%) and thus their suitability for its use. The combination of electrophoretic karyotype and the simplified morphotypes was rapid and practical to characterize the different clusters involved in the intensive care unit outbreak.

Base Sequence↗

Role of environmental cleaning in controlling an outbreak of Acinetobacter baumannii on a neurosurgical intensive care unit.

An outbreak of Acinetobacter baumannii colonization and infection occurred in 19 patients over a 14-month period during 1998-1999 on a neurosurgical intensive care unit. During efforts to control the outbreak a significant correlation was observed between the number of environmental isolates of A. baumannii obtained during each monthly screening and the number of patients with A. baumannii colonization/infection in the same calendar month (P=0.004). Use of 1000 ppm hypochlorite solution and the introduction of new cleaning protocols reduced the number of environmental isolates. Failure to maintain low levels of environmental contamination with A. baumannii resulted in increases in patient colonization. This study showed that high standards of cleaning play an integral role in controlling outbreaks of A. baumannii in the intensive care unit setting.

Acinetobacter Infections↗

Molecular investigation of an outbreak of multidrug-resistant Acinetobacter baumannii, with characterisation of class 1 integrons.

We investigated a multidrug-resistant Acinetobacter baumannii outbreak in the Intensive Care Unit (ICU) of a tertiary care hospital in Greece over a 3-month period. Molecular typing of the outbreak isolates from 31 patients revealed that two distinct genotypes were involved. Nine isolates, belonging to both genotypes, were resistant to carbapenems. Samples from the ICU environment and from the hands of personnel were collected to identify possible contamination. Class 1 integrons of 3.1, 2.5 and 2.2 kb were amplified from the clinical and environmental isolates. The 3.1 kb integron carrying five gene cassettes was found for the first time in A. baumannii. The outbreak ceased after implementation of hygienic measures in the ICU, including complete cleaning and disinfection.

Acinetobacter Infections↗

Dose response modelling of Escherichia coli O157 incorporating data from foodborne and environmental outbreaks.

A human dose response model for Escherichia coli O157 would enable prediction of risk of infection to humans following exposure from either foodborne or environmental pathways. However, due to the severe nature of the disease, volunteer human dose response studies cannot be carried out. Surrogate models from Shigella fed to humans and E. coli O157 to rabbits have been utilised but are significantly different to one another. In addition data obtained by animal exposure may not be representative for human beings. An alternative approach to generating and validating a dose response model is to use quantitative data obtained from actual human outbreaks. This work collates outbreak data obtained from global sources and these are fitted using exponential and beta-Poisson models. The best fitting model was found to be the beta-Poisson model using a beta-binomial likelihood and the authors favour the exact version of this model. The confidence levels in this model encompass a previously published Shigella dose response model. The potential incorporation of this model into QMRAs is discussed together with applications of the model to help explain foodborne outbreaks.

Animals↗

Comparison of genotyping methods by application to Salmonella livingstone strains associated with an outbreak of human salmonellosis.

During 2000 and 2001, an outbreak of human salmonellosis occurred in Sweden and Norway, caused by Salmonella livingstone. In this study, the genotypic differences between three strains obtained from food sources during the outbreak, two human strains and 27 more or less unrelated strains were analysed, using the three methods; automated ribotyping, pulsed field gel electrophoresis (PFGE) and randomly amplified polymorphic DNA (RAPD). Each method was evaluated regarding its discriminatory ability, reproducibility and typeability. Simpson's discriminatory index calculated for each method was 0.556 for automated ribotyping, 0.766 for PFGE and 0.236 for RAPD. The reproducibility, defined as the minimum similarity between individual replicates in a cluster analysis, was 96% for automated ribotyping and PFGE, and 90% for RAPD. All the strains were typeable with each method. When combining results for the three genotyping methods, it was found that RAPD did not increase the discriminatory index and was therefore excluded from further analysis. Using a combination of the results obtained from ribotyping and PFGE (D=0.855), two strains that had been isolated from feed factories during 1998 were shown to be identical to the outbreak strain, indicating a possible route of contamination due to a clone of Salmonella livingstone persisting in feed producing facilities. No connection to poultry was established.

Animal Feed↗

An outbreak of food-borne listeriosis due to cheese in Japan, during 2001.

Food-borne outbreaks caused by Listeria monocytogenes have been recognized in US and European countries. Only sporadic cases, of neonatal listeriosis, have been reported in Japan. Since L. monocytogenes has been often isolated from foods in Japan, food-borne outbreaks potentially could have occurred. In February 2001, L. monocytogenes serotype 1/2b was isolated from a washed-type cheese during routine Listeria monitoring of 123 domestic cheeses. Further samples from products and the environments at the plant that produced the contaminated cheese were examined for L. monocytogenes. L. monocytogenes serotype 1/2b was detected in 15 cheese samples, at most probable number that ranged from <30 to 4.6 x 10(9)/100 g, and in environmental samples. Studies with people who had consumed cheese from the plant revealed 86 persons who had been infected with L. monocytogenes. Thirty-eight of those people had developed clinical symptoms of gastroenteritis or the common cold type after the consumption of cheese. Isolates from those patients exhibited the same serotype, pathogenicity for mice and HeLa cells, DNA fingerprinting patterns and PCR amplification patterns. From the epidemiological and genetic evidence, it appeared that the outbreak was caused by cheese. This is the first documented incidence of food-borne listeriosis in Japan.

Cheese↗

PCR identification of the plasmid-borne enterotoxin gene (cpe) in Clostridium perfringens strains isolated from food poisoning outbreaks.

It is generally accepted that Clostridium perfringens strains associated with food poisoning carry their enterotoxin gene, cpe, on the chromosome, while C. perfringens strains isolated from non-food-borne diseases, such as antibiotic-associated diarrhea and sporadic diarrhea, carry cpe on the plasmid. However, we recently encountered a food poisoning outbreak caused by C. perfringens bearing a plasmid cpe. We therefore investigated a total of 31 clinical and non-clinical C. perfringens strains to locate the cpe gene by PCR. The cpe of nine heat-sensitive (100 degrees C for 10min) strains isolated from three outbreaks of food poisoning were located on the plasmid, while those of six heat-resistant strains from other food poisoning outbreaks were located on the chromosome. Moreover, the cpe of 5 heat-sensitive strains isolated from healthy human feces and those of 11 heat-sensitive soil strains were also located on the plasmid. These findings indicate that heat-sensitive, cpe-plasmid-borne C. perfringens strains should not be disregarded as causative agents of food poisoning.

Chromosomes, Bacterial↗

Implementation of the Hospital Emergency Incident Command System during an outbreak of severe acute respiratory syndrome (SARS) at a hospital in Taiwan, ROC.

We sought to describe the implementation of the Hospital Emergency Incident Command System (HEICS) at National Cheng Kung University Hospital (NCKUH) in Taiwan, ROC during the outbreak of severe acute respiratory syndrome (SARS) in early 2003. We administered a 14-question survey via structured interviews to individuals occupying activated HEICS leadership positions at NCKUH to identify the organization, structure, and function of the HEICS units and subunits they led and the job actions they performed from 25 March to 16 June 2003 Thirty-three of 38 persons (87%) occupying 39 of 44 (89%) activated HEICS leadership positions directly participated in the survey. The participants collectively reported: 1) the creation of four new HEICS unit leader positions and corresponding units during the outbreak, including the infection control officer (administrative section) and SARS assessment, isolation, and critical care unit leaders (operations section); 2) the creation of six new HEICS subunits, including functional areas for fever screening, SARS assessment, and resuscitation outside the hospital, and SARS patient care, SARS critical care, and employee isolation inside the hospital; and 3) the performance of new job actions related to infection control by all HEICS unit leaders. HEICS provides a flexible framework that seems to have assisted NCKUH in the organization of its emergency response to the SARS outbreak in Taiwan, ROC.

Cross-Sectional Studies↗

An outbreak of hepatitis A virus infection with a high case-fatality rate among injecting drug users.

BACKGROUND/AIMS: In 2002, the first reported outbreak of hepatitis A virus (HAV) infection involving mostly intravenous drug users (IDU) occurred in Italy. We attempted a thorough evaluation of the outbreak, including epidemiological, clinical and virological analyses. METHODS: We conducted an epidemiological investigation, including a case-control study, to identify the source and the modes of HAV transmission. Hepatitis B and C (HCV) viruses and human immunodeficiency virus (HIV) coinfections were clinically analysed. Sequence analysis of the VP1/2A junction of the HAV isolates was also performed. RESULTS: Of the 47 symptomatic cases, 35 were IDUs. The only associated risk factor was contact (not related to injecting practices) with a jaundiced person (odds ratio: 5.8; 95% confidence interval: 1.3-29.9). Of the cases, 58% were anti-HCV positive and 4.7% anti-HIV positive. Three individuals died of acute liver failure: 2 were HCV-coinfected alcohol abusers, with underlying liver cirrhosis; 1 was HCV/HIV-coinfected. HAV-RNA was found in 15 of the 24 tested patients: genotype IB (8 cases) and IIIA (7 cases) were detected. CONCLUSIONS: HAV was probably transmitted through the fecal-oral route, although parenteral transmission cannot be excluded. The high fatality rate was probably due to severe underlying liver damage. The occurrence of this outbreak highlights the need for routine HAV vaccination for IDUs.

Adolescent↗

Role of environmental cleaning in controlling an outbreak of Acinetobacter baumannii on a neurosurgical intensive care unit.

An outbreak of Acinetobacter baumannii colonization and infection occurred in 19 patients over a 14-month period during 1998-1999 on a neurosurgical intensive care unit. During efforts to control the outbreak a significant correlation was observed between the number of environmental isolates of A. baumannii obtained during each monthly screening and the number of patients with A. baumannii colonization/infection in the same calendar month (P < 0.004). Use of 1000 ppm hypochlorite solution and the introduction of new cleaning protocols reduced the number of environmental isolates. Failure to maintain low levels of environmental contamination with A. baumannii resulted in increases in patient colonization. This study showed that high standards of cleaning play an integral role in controlling outbreaks of A. baumannii in the intensive care unit setting.

Acinetobacter Infections↗

Investigation of a pyoderma outbreak caused by methicillin-susceptible Staphylococcus aureus in a nursery for newborns.

An outbreak of pyoderma caused by methicillin-susceptible Staphylococcus aureus occurred in a nursery for newborns over 26 days. During this period, six neonates were involved. The mother of the first case had trunk pyoderma before delivery, which was regarded as the source of the outbreak. Contamination of the environment and equipment were implicated as the reservoirs of further pathogen spread, as supported by pulsed-field gel electrophoresis (PFGE) results, which showed that some screening isolates were indistinguishable from the epidemic strain. Termination of the outbreak was achieved by the reinforcement of infection control practices and disinfection of environmental surfaces.

Cross Infection↗