Do Microbial Interactions and Cultivation Media Decrease the Accuracy of Salmonella Surveillance Systems and Outbreak Investigations?

2009 ◽  
Vol 72 (4) ◽  
pp. 707-713 ◽  
Author(s):  
RANDALL S. SINGER ◽  
ANNE E. MAYER ◽  
TIMOTHY E. HANSON ◽  
RICHARD E. ISAACSON

Cultivation methods are commonly used in Salmonella surveillance systems and outbreak investigations, and consequently, conclusions about Salmonella evolution and transmission are highly dependent on the performance characteristics of these methods. Past studies have shown that Salmonella serotypes can exhibit different growth characteristics in the same enrichment and selective media. This could lead not only to biased conclusions about the dominant strain present in a sample with mixed Salmonella populations, but also to a low sensitivity for detecting a Salmonella strain in a sample with only a single strain present. The objective of this study was to determine whether cultivation media select preferentially for specific strains of Salmonella in heterogeneous cultures. In this study, four different Salmonella strains (one Salmonella Newport, two Salmonella Typhimurium, and one Salmonella Enteritidis) were competed in a broth-based experiment and a bovine fecal experiment with varied combinations and concentrations of each strain. In all experiments, the strain of Salmonella Newport was the most competitive, regardless of the starting concentration and cultivation protocol. One strain of Salmonella Typhimurium was rarely detected in competition, even when it was the only strain present in bovine feces. Overall, the probability of detecting a specific Salmonella strain had little to do with its starting concentration in the sample. The bias introduced by culture could be dramatically biasing Salmonella surveillance systems and hindering traceback investigations during Salmonella outbreaks. Future studies should focus on the microbiological explanations for this Salmonella interstrain variability, approaches for minimizing the bias, and estimations of the public health significance of this bias.

2008 ◽  
Vol 71 (10) ◽  
pp. 2153-2160 ◽  
Author(s):  
KIRK E. SMITH ◽  
CARLOTA MEDUS ◽  
STEPHANIE D. MEYER ◽  
DAVID J. BOXRUD ◽  
FE LEANO ◽  
...  

From 1998 through 2006, four outbreaks of salmonellosis associated with raw, frozen, microwaveable, breaded, pre-browned, stuffed chicken products were identified in Minnesota. In 1998, 33 Salmonella Typhimurium cases were associated with a single brand of Chicken Kiev. In 2005, four Salmonella Heidelberg cases were associated with a different brand and variety (Chicken Broccoli and Cheese). From 2005 to 2006, 27 Salmonella Enteritidis cases were associated with multiple varieties of product, predominately of the same brand involved in the 1998 outbreak. In 2006, three Salmonella Typhimurium cases were associated with the same brand of product involved in the 2005 Salmonella Heidelberg outbreak. The outbreak serotype and pulsed-field gel electrophoresis subtype of Salmonella were isolated from product in each outbreak. In these outbreaks, most individuals affected thought that the product was precooked due to its breaded and prebrowned nature, most used a microwave oven, most did not follow package cooking instructions, and none took the internal temperature of the cooked product. Similar to previous salmonellosis outbreaks associated with raw, breaded chicken nuggets or strips in Canada and Australia, inadequate labeling, consumer responses to labeling, and microwave cooking were the key factors in the occurrence of these outbreaks. Modification of labels, verification of cooking instructions by the manufacturer, and notifications to alert the public that these products contain raw poultry, implemented because of the first two outbreaks, did not prevent the other outbreaks. Microwave cooking is not recommended as a preparation method for these types of products, unless they are precooked or irradiated prior to sale.


2010 ◽  
Vol 73 (11) ◽  
pp. 2053-2058 ◽  
Author(s):  
CARLOTA MEDUS ◽  
KIRK E. SMITH ◽  
JEFFREY B. BENDER ◽  
FE LEANO ◽  
CRAIG W. HEDBERG

The frequency of Salmonella-infected food workers identified through routine surveillance from 1997 to 2004 in Minnesota was determined in order to evaluate the impact of surveillance on the detection of outbreaks in restaurants and to quantify the duration of Salmonella shedding in stool. Of 4,976 culture-confirmed Salmonella cases reported to the Minnesota Department of Health, 110 (2.2%) were identified as food workers; this was less than one-half the number expected based on the incidence of Salmonella in the general population. Twenty food workers (18%) were associated with outbreaks. Twelve were involved in nine independent outbreaks at the restaurants where they worked. The identification of the index food worker in six of these outbreaks was critical to the initiation of outbreak investigations that revealed much larger problems. Among food workers who submitted specimens until at least one negative result was obtained (n = 69), the median duration of shedding was 22 days (range, 1 to 359 days). Among the four most common serotypes (Enteritidis, Typhimurium, Heidelberg, and Newport) the median duration of shedding was significantly longer for Salmonella Newport (80 days; P = 0.02) and for Salmonella Enteritidis (32 days; P = 0.04) than for Salmonella Heidelberg (8 days). Food workers should be considered an important source of Salmonella transmission, and those identified through surveillance should raise a high index of suspicion of a possible outbreak at their place of work. Food service managers need to be alert to Salmonella-like illnesses among food workers to facilitate prevention and control efforts, including exclusion of infected food workers or restriction of their duties.


2010 ◽  
Vol 30 (2) ◽  
pp. 155-160 ◽  
Author(s):  
Márcio G. Ribeiro ◽  
Marta C. Fernandes ◽  
Antonio C. Paes ◽  
Amanda K. Siqueira ◽  
José P.A.N. Pinto ◽  
...  

Foram caracterizados os sorotipos, o perfil de sensibilidade microbiana e os achados clínico-epidemiológicos em 53 linhagens do gênero Salmonella isoladas de 41 cães, nove equinos e três bovinos, acometidos por diferentes manifestações clínicas entre 1997 e 2007. Salmonella Typhimurium (45,3%), Salmonella enterica (22,6%), Salmonella Enteritidis (7,5%), Salmonella enterica subsp enterica 4,5,12i (5,7%), Salmonella Newport (5,7%), Salmonella Dublin (3,8%), Salmonella Agona (3,8%), Salmonella Glostrup (3,8%), Salmonella Saintpaul (1,8%) foram os sorotipos encontrados. Ciprofloxacina (100,0%), norfloxacina (100,0%) e gentamicina (100,0%) foram os antimicrobianos mais efetivos, enquanto a maior resistência das linhagens foi observada para ceftiofur (28,5%) e florfenicol (7,0%). As linhagens foram isoladas de animais com enterite, infecção do trato urinário, septicemia, piometra, pneumonia e conjuntivite. Ressalta-se para o predomínio do sorovar Typhimurium nas diferentes manifestações da salmonelose nos animais. Destaca-se, também, a identificação de sorotipos nos animais que também são observados em casos de salmonelose em humanos


2018 ◽  
Vol 51 (4) ◽  
pp. 288
Author(s):  
A. ZDRAGAS (Α. ΖΔΡΑΓΚΑΣ) ◽  
V. PETSAGA-TSIMPERI (Β. ΠΕΤΣΑΓΚΑ-ΤΣΙΜΠΕΡΗ) ◽  
P. TSAKOS (Π. ΤΣΑΚΟΣ)

The presence of Salmonella spp. in the diarrhoeic syndrome of 24 cases of calves, 36 cases of kids and 14 cases of lambs was investigated. Salmonella was isolated as the pathogenic agent from six herds of calves and four cases of kids. The identified species was Salmonella enteritidis in three herds of calves and two cases of kids. Salmonella typhimurium was identified in two herds of calves and one case of kids. Also, Salmonella abony and Salmonella cerro were identified in one case of calves and kids, respectively. Furthermore, Shigella hyodysenteriae was isolated from two cases of diarrhoeic syndrome in lambs. All the infected animals were characterized by persistent haemorrhagic diarrhoea and high mortality. The occurrence of Salmonella enteritidis in ruminants is probably an important point of the epidemiology of Salmonella spp. and may play a significant role in the public health.


Author(s):  
Pamela Keel

The epidemiology of eating disorders holds important clues for understanding factors that may contribute to their etiology. In addition, epidemiological findings speak to the public health significance of these deleterious syndromes. Information on course and outcome are important for clinicians to understand the prognosis associated with different disorders of eating and for treatment planning. This chapter reviews information on the epidemiology and course of anorexia nervosa, bulimia nervosa, and two forms of eating disorder not otherwise specified, binge eating disorder and purging disorder.


2009 ◽  
Vol 20 (3) ◽  
pp. 73-77 ◽  
Author(s):  
Mark J Kearns ◽  
Sabrina S Plitt ◽  
Bonita E Lee ◽  
Joan L Robinson

BACKGROUND: There are limited recent data on rubella immunity in women of childbearing age in Canada. In the present paper, the proportion of rubella seroreactivity and redundant testing (testing of women previously seropositive when tested by the same physician) in the Alberta prenatal rubella screening program were studied.METHODS: In the present retrospective observational study, data on all specimens submitted for prenatal screening in Alberta between August 2002 and December 2005 were extracted from the Provincial Laboratory for Public Health database. The proportion of rubella screening and immunoglobulin G (IgG) seroreactivity were determined. Demographic variables were compared between rubella seroreactors and nonseroreactors. The proportion of redundant testing was determined.RESULTS: Of 159,046 prenatal specimens, 88.3% (n=140,473) were screened for rubella immunity. In total, 8.8% of specimens tested negative for rubella IgG. Younger women (23.2% of women younger than 20 years of age versus 4.7% of women between 35 and 39 years of age; P<0.001) and women from northern Alberta (11.9% versus 8.1% [overall]; P<0.001) were significantly more likely to have seronegative specimens. Of the 20,044 women who had multiple rubella immunity screenings, 88.1% (n=17,651) had multiple positive test results. In total, 20.7% of the 42,274 specimens submitted from women with multiple screenings were deemed redundant.DISCUSSION: Younger women were most likely to be seronegative for rubella. The public health significance of women entering their childbearing years with low or undetectable rubella IgG levels remains to be determined. A large number of women with documented rubella immunity were unnecessarily retested.


2021 ◽  
Vol 9 (2) ◽  
pp. 398
Author(s):  
Dong Chan Moon ◽  
Su-Jeong Kim ◽  
Abraham Fikru Mechesso ◽  
Hee Young Kang ◽  
Hyun-Ju Song ◽  
...  

Colistin is considered the last resort for the treatment of multi-drug resistant Gram-negative bacterial infections. We studied colistin resistance and the mcr-1 gene carriage in Salmonella isolates recovered from food animals in South Korea between 2010 and 2018. Colistin resistance was found in 277 isolates, predominantly in Salmonella Enteritidis (57.1%) and Salmonella Gallinarum (41.9%). However, the mcr-1 gene was identified in only one colistin-resistant Salmonella Typhimurium (MIC = 16 µg/mL) isolated from a healthy pig. The mcr-1 carrying isolate presented additional resistance to multiple antimicrobials. The strain belonged to sequence type (ST)19 and carried various virulence factor genes that are associated with adhesion and invasion of Salmonella into intestinal epithelial cells, as well as its survival in macrophages. The mcr-1 gene was identified on an IncI2 plasmid and it was also transferred to the E. coli J53 recipient strain. The mcr-1-carrying plasmid (pK18JST013) in this study was closely related to that previously reported in S. Indiana (pCFSA664-3) from chicken in China. This is the first report of mcr-1 carrying S. Typhimurium in South Korea. The finding indicates the importance of regular screening for the presence of the mcr-1 gene in S. Typhimurium in food animals to prevent the spread to humans.


2021 ◽  
pp. 1-6
Author(s):  
Esra AlHamadani ◽  
Sania Zia ◽  
Ali AlRahma ◽  
Firas AlNajjar

<b><i>Objectives:</i></b> Several studies promoted anosmia as a possible isolated symptom for coronavirus disease 2019 (COVID-19). No studies used feasible methods of smell testing that the public would use to address the accuracy of these claims. <b><i>Methods:</i></b> This is a single-center study conducted between April 2020 and June 2020. The sense of smell was tested in vitally stable suspected COVID-19 patients with no/mild upper respiratory tract infection symptoms prior to nasopharyngeal swabbing for reverse-transcriptase polymerase chain reaction. Patients were instructed to close their eyes. Each nostril was tested separately while the other was blocked with the patient’s index finger. Patients inhaled from 2 concealed vials (coffee and strawberry essence) consecutively, kept within 30 cm of the nostril for 60 s. Patients who could not identify both odors with both nostrils were recorded as “anosmia.” <b><i>Results:</i></b> Out of 346 eligible subjects, 43 had anosmia of which 26 (60%) tested COVID-19 positive. χ<sup>2</sup> test showed a <i>p</i> value &#x3c;0.001. The test showed a sensitivity of 30% (95% confidence interval [CI] 21%, 41%) and specificity 94% (95% CI 90%, 96%). Logistic regression revealed an odds ratio of 5.9 (95% CI 3.0, 12) <i>p</i> value &#x3c;0.001. <b><i>Conclusion:</i></b> Given the low sensitivity (30%) of this method in detecting COVID-19 infection, we conclude that this method is not a useful screening tool for COVID-19 infection. The moderate negative predictive value (80%) is nongeneralizable.


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