A nosocomial outbreak of Salmonella enteritidis associated with lyophilized enteral nutrition

An isolated case of nosocomial acquisition of invasive non-typhoidal Salmonella

Non-typhoidal Salmonella spreads to humans via contact with animals or consumption of contaminated animal products, often causing outbreaks of a self-resolving gastroenteritis. Less commonly, it can lead to bacteremia and invasive disease. Nosocomial, person-to-person, and asymptomatic carrier transmission are uncommon in the United States. Reactivation of latent Salmonella in immunocompromised patients is also a known phenomenon. Here, we report a case of an isolated Salmonella bacteremia that developed in an intubated patient with a prolonged hospital course and no clear outbreak or focus of infection. Non-traditional means of transmission and reactivation of latent Salmonella should be considered in the absence of an outbreak phenomenon, especially in patients with multiple comorbidities and immunocompromise.

Epidemiological and Molecular Investigations on Salmonella Responsible for Gastrointestinal Infections in the Southwest of Shanghai From 1998 to 2017

Purpose

To investigate the characteristics of gastrointestinal infections in Southwest Shanghai.

Methods

Clinical and epidemiological characteristics of patients with Salmonella infections between 1998 and 2017 admitted to the Jinshan Hospital in the Southwest of Shanghai were retrospectively analyzed. A total of 565 isolated Salmonella strains were classified by serotyping and pulsed field gel electrophoresis (PFGE).

Results

From 1998 to 2006, diarrhea was mainly caused by Vibrio parahaemolyticus followed by Shigella and Salmonella. From 2007 to 2010, Vibrio parahaemolyticus infection was the major cause of diarrhea followed by Salmonella and Shigella. From 2011 to 2017, Salmonella infections became the main cause of diarrhea after Vibrio parahaemolyticus. Salmonella infections increased from 2006 on and peaked between May and October, accounting for 82.48% of yearly infections. Patients with Salmonella infections (90.5%) had a history of eating unclean food, abdominal pain (58.05%), diarrhea ≥5 times a day (50.44%), moderate fever (24.96%) and increased fecal leukocytes (41.42%). From 1998 to 2017, infected specimens from clinical cases were dominated by Salmonella enterica serovar Typhimurium (S. Typhimurium) (21.59%) followed by Salmonella enterica serovar Enteritis (S. Enteritidis) (16.81%), Salmonella enterica serotype London (6.55%) and Salmonella group B (13.10%). Other species included Salmonella enterica serovar Thompson, Salmonella enterica serovar Saintpaul, Salmonella group D, Salmonella group C, Salmonella enterica serovar Choleraesuis and Salmonella enterica serovar Aberdeen. The PFGE classification of Salmonella serovars in 2008–2017 demonstrated that S. Enteritidis had 9 PFGE banding patterns and S. Typhimurium 16 with varying degrees of similarity among S. Enteritidis and S. Typhimurium. The results of antibiotic susceptibility tests for the 330 Salmonella strains revealed that fosfomycin had the highest sensitivity rate (97.5%) followed by levofloxacin and ceftriaxone (81%), and ampicillin/sulbactam (78.2%). The resistance to piperacillin and ciprofloxacin was 60.9 and 50.61%, respectively.

Conclusion

The features of onset, epidemiological characteristics and molecular subtyping of Salmonella were conducive to clinical diagnosis, rational use of antibiotics and improved therapeutic efficacy.

The Role of Patient Care Items as a Fomite in Healthcare-Associated Outbreaks and Infection Prevention

Patient-care items can serve as a source or reservoir for healthcare-associated pathogens in hospitals. We reviewed healthcare- associated outbreaks from medical equipment and provide infection prevention recommendations. Multiple healthcare-associated outbreaks via a contaminated patient-care item were identified, including infections with multidrug-resistant organisms. The type of patient care items implicated as a fomite causing healthcare-associated infections (HAIs) has changed over time. Patient populations at risk were most commonly critically ill patients in adult and neonatal intensive care units. Most fomite related healthcare-associated outbreaks were due to inappropriate disinfection practices. Repeated healthcare-associated outbreaks via medical equipment highlight the need for infectious disease professionals to understand that fomites/medical devices may be a source of HAIs. The introduction of new and more complex medical devices will likely increase the risk that such devices serve as a source of HAIs. Assuring appropriate cleaning and disinfection or sterilization of medical equipment is necessary to prevent future fomite-associated outbreaks.

Evaluating the quality of outbreak reports on health care-associated infections in São Paulo, Brazil, during 2000-2010 using the ORION statement findings and recommendations

BACKGROUND

The standard of outbreak reports must be improved to a level where they are robust enough to properly influence preventive strategies. We aimed to verify compliance with mandatory outbreak notification, describing epidemiologic characteristics and management, and evaluating the quality of outbreak reports on health care-associated infections in São Paulo State, Brazil.

METHODS

A systematic search was carried out on PubMed, the Latin American and Caribbean Health Sciences Literature database, Embase, Outbreak Database, the Annals of Brazilian Conferences on Healthcare-Associated Infection Prevention and Infectious Diseases, and reports from the São Paulo State Hospital Infection Division. The quality of reports was evaluated according to the Outbreak Reports and Intervention studies of Nosocomial Infection (ORION) statement guidelines.

RESULTS

A total of 87 outbreak reports were identified; however, only 15 outbreaks (17.2%) were reported to the São Paulo State Hospital Infection Division. Bloodstream infection and neonatal intensive care units were mostly implicated (23% and 19.5%, respectively). Quality, evaluated according to ORION statement recommendations, was generally poor. The ORION categories of Background, Objectives, Participants, Setting, Infection-Related Outcomes, and Generality were properly described in 32.2%, 74.7%, 2.3%, 46%, 2.3%, and 12.6% of reports, respectively. Interventions and Culture-Typing were described with details in 51.9% and 55.2% of outbreak reports, respectively.

CONCLUSIONS

Our findings pointed out the need for strategies to improve competence in outbreak reports, and the ORION statement guidelines may help in this matter. Efforts to promote confidence and consequent compliance with mandatory notification of outbreak reports are essential.

Dehydrated egg white: an allergen source for improving efficacy and safety in the diagnosis and treatment for egg allergy

BACKGROUND

Raw and cooked eggs are used as allergens in oral food challenge (OFC). Raw egg is the best option, as it keeps proteins intact and retains their allergenicity, albeit microbiologically safe manipulation is difficult. Therefore, the use of dehydrated egg white (DEW) could improve the efficacy and safety profile of OFC. The aim of the study was to compare the allergenicity of DEW, a product that undergoes a double heat treatment (pasteurization and drying), with that of raw egg white (REW) and determine the efficacy of DEW in the diagnosis of egg allergy.

METHODS

We conducted a prospective study of 40 egg-allergic patients who visited our outpatient clinic. Each patient underwent OFC with DEW and REW to determine the correlation between the tests. DEW and REW extracts were analyzed using SDS-PAGE. We compared the allergenicity of both extracts using IgE immunoblotting with a serum pool from patients with positive OFC results.

RESULTS

Ten patients (25%) had positive OFC results with both DEW and REW, and the doses that triggered an allergic reaction in each patient were similar (p > 0.05). All 30 patients (75%) with a negative OFC result with DEW also had negative OFC results with REW. SDS-PAGE and IgE immunoblotting revealed that the protein composition and IgE-binding capacity of both extracts were virtually identical.

CONCLUSIONS

This is the first time that it is shown that the allergenicity of commercially available DEW is equivalent to raw egg whites. In vivo and in vitro tests showed that processing of DEW does not affect the allergenicity of egg proteins. DEW is an effective and microbiologically safer source of allergen for the diagnosis of egg allergy. Furthermore, DEW can be used in egg oral immunotherapy.

Genetic diversity, virulence genes and antimicrobial resistance of Salmonella Enteritidis isolated from food and humans over a 24-year period in Brazil

Salmonellosis is a major health problem worldwide. Serovar Enteritidis has been a primary cause of Salmonella outbreaks in many countries. In Brazil, few molecular typing studies have been performed. The aims of this study were to molecularly type Salmonella Enteritidis strains isolated in Brazil in order to determine the genetic relationship between strains of food and human origin, as well as, to assess their pathogenic potential and antimicrobial resistance. A total of 128 S. Enteritidis strains isolated from human feces (67) and food (61) between 1986 and 2010 were studied. The genotypic diversity was assessed by ERIC-PCR and PFGE using XbaI, the antimicrobial resistance by the disc-diffusion assay and the presence of the SPI-1, SPI-2 and pSTV virulence genes assessed by PCR. The ERIC-PCR results revealed that 112 strains exhibited a similarity of >85.4% and the PFGE that 96 strains exhibited a similarity of >80.0%. Almost all strains (97.6%) harbored all 13 virulence genes investigated. Thirty-six strains (28.12%) were resistant to nalidixic acid. In conclusion, the nalidixic acid resistance observed after 1996 is indicative of an increase in the use of this drug. It may be suggested that these 128 strains might have descended from a common ancestor that differed little over 24 years and has been both contaminating food and humans and causing disease for more than two decades in Brazil.

An outbreak ofSalmonellaInfantis gastroenteritis in a residential aged care facility associated with thickened fluids

Twenty-two confirmed cases ofSalmonellaInfantis were identified in 70 residents of high-level care areas of a residential aged care facility in Sydney in April 2010 during an outbreak of gastroenteritis. A retrospective cohort study was conducted to identify a possible cause. Consuming a soft diet, puréed diet, or thickened fluid were each independently associated with illness. A logistic regression showed consumption of thickened fluid to be the only significant exposure associated with illness (adjusted odds ratio 11·8, 95% confidence interval 1·9–75·9). It was postulated that the thickened fluid had been contaminated by chicken mince, a sample of which also culturedS. Infantis. This finding reinforces the need to educate food-handlers on the risk of potential cross-contamination; it also highlights the need to consider all dietary components, such as thickened fluids, as potential vehicles for transmission in an outbreak.

Analysis of an outbreak of Salmonella enteritidis by repetitive-sequence-based PCR and pulsed-field gel electrophoresis

OBJECTIVE

The aim of this study was to investigate a large food-borne outbreak associated with eggs contaminated by Salmonella Enteritidis in a military unit using pulse field gel electrophoresis (PFGE) and the Repetitive-sequence-based PCR (rep-PCR) employing the DiversiLab system.

MATERIALS AND METHODS

In mid-January 2008, a food-borne outbreak associated with S. Enteritidis occurred in a military unit located in the city centre of Isparta. A total of 2,469 patients were registered to six hospitals with gastrointestinal disease symptoms such as diarrhea and abdominal pain. Of those registered, 445 were hospitalized. S. Enteritidis was isolated from 276 stool samples and a blood sample of the hospitalized patients and from a food item. The PFGE patterns after XbaI digestion and rep-PCR profiles produced by the DiversiLab system were determined for eight randomly selected stool isolates, one blood isolate and one food isolate.

RESULTS

The PFGE patterns of all isolates were identical. The Rep-PCR profiles produced by using the DiversiLab system showed that all isolates were indistinguishable. The PFGE and rep-PCR interpretations were concordant for the S. Enteritidis isolates. All stool isolates, one blood isolate and one food isolate were susceptible to all antibiotics tested.

CONCLUSION

This data suggest that the DiversiLab system may be a reasonable alternative to PFGE for investigation and control of S. Enteritidis outbreaks, since it is easy to use, rapid and does not require highly skilled operators.

Diagnosis and treatment of acute or persistent diarrhea

Studies of microbial pathogens and the toxins they produce are important for determining the mechanisms by which they cause disease and spread throughout a population. Some bacteria produce secretory enterotoxins (such as cholera toxin or the heat-labile or stable enterotoxins produced by Escherichia coli) that invade cells directly. Others invade cells or produce cytotoxins (such as those produced by Shigella, enteroinvasive E coli, or Clostridium difficile) that damage cells or trigger host responses that cause small or large bowel diseases (such as enteroaggregative or enteropathogenic E coli or Salmonella). Viruses (such as noroviruses and rotaviruses) and protozoa (such as Cryptosporidium, Giardia, or Entamoeba histolytica) disrupt cell functions and cause short- or long-term disease. Much epidemiologic data about these pathogens have been collected from community- and hospital-acquired settings, as well as from patients with traveler's or persistent diarrhea. These studies have led to practical approaches for prevention, diagnosis, and treatment.

Validation of a predictive model describing growth of Salmonella in enteral feeds

Cellulase is a complex enzyme system, commercially produced by filamentous fungi under solid-state and submerged cultivation. It has wide applicability in textile, food and beverage industry for effective saccharification process. In this study, cellulolytic enzyme activity, particularly endoglucanase of 26 Streptomyces strains isolated from garden soil was examined, including two isolates selected on the basis of potential cellulolytic activity on Bennett’s agar medium. To enhance the endoglucanase formation in broth culture, different conditions including carbon and nitrogen sources, and growth conditions were tested. The maximum endoglucanase activity (11.25-11.90 U/mL) was achieved within 72-88 h in fermentation medium containing Tween-80, followed by phosphate sources. Both cellulolytic Streptomyces isolates gave almost equal quantity of enzyme in all trials. However the effect of medium ingredients on endoglucanase induction diverged with strains in some extent.

Outbreak of extended spectrum beta-lactamase-producing Klebsiella pneumoniae infection in a neonatal intensive care unit related to onychomycosis in a health care worker

Four cases of infection by extended spectrum beta-lactamase-producing Klebsiella pneumoniae occurred in the neonatal intensive care unit. Isolation, empiric therapy change and education produced no effect. Newborn weekly colonization rates were 0-18.7%. One health care worker with onychomycosis was positive for extended spectrum beta-lactamase-producing K. pneumoniae. Isolates were identical by molecular typing. Outbreak was controlled when the health care worker was excluded from the neonatal intensive care unit.