Extraintestinal focal infections in adults with nontyphoid Salmonella bacteraemia: predisposing factors and clinical outcome

Curing of a field strain of Salmonella enterica serovar Infantis isolated from poultry from its highly stable pESI like plasmid

Salmonella enterica serovar Infantis (S. infantis) is an important emerging pathogen, associated with poultry and poultry products and related to an increasing number of human infections in many countries. A concerning trend among S. infantis isolates is the presence of plasmid-mediated multidrug resistance. In many instances, the genes responsible for this resistance are carried on a megaplasmid known as the plasmid of emerging S. infantis (pESI) or pESI like plasmids. Plasmids can be remarkably stable due to the presence of multiple replicons and post-segregational killing systems (PSKs), which contribute to their maintenance within bacterial populations. To enhance our understanding of S. infantis and its multidrug resistance determinants toward the development of new vaccination strategies, we have devised a new method for targeted plasmid curing. This approach effectively overcomes plasmid addiction by leveraging the temporal overproduction of specific antitoxins coupled with the deletion of the partition region. By employing this strategy, we successfully generated a plasmid-free strain from a field isolate derived from S. infantis 119,944. This method provides valuable tools for studying S. infantis and its plasmid-borne multidrug resistance mechanisms and can be easily adopted for plasmid curing from other related bacteria.

Non-typhoidal Salmonella enteritidis prosthetic valve endocarditis

In this case, we present a rare cause of prosthetic valve endocarditis. A man in his 80s presented to the emergency department with fever and diarrhoea. The patient underwent a transcatheter aortic valve replacement 17 years earlier. A negative PCR result in faeces for Salmonella and positive blood cultures with Salmonella gave rise to the suspicion of an intravascular Salmonella infection, which was confirmed with a positron emission tomography. Due to the low prevalence of Salmonella endocarditis, there is no consensus on the most effective treatment. Guidelines recommend early surgery and long-term antimicrobial treatment in endocarditis with Gram-negative bacteria. In this case, surgery was not deemed feasible given the patient his advanced age and multiple comorbidities. Despite treatment with intravenous antibiotics, the patient succumbed to progression of endocarditis 37 days after admission.

A Diagnostic Conundrum: Tuberculosis or Salmonella Neck Abscess?

Granulomatous neck abscesses are commonly associated with tuberculosis (TB). These chronic inflammatory reactions are rarely seen in Salmonella non-typhi (SN) infections. We report two cases of SN granuloma presenting as neck abscesses in poultry farmers. TB polymerase chain reactions (PCR) were negative. Histopathology reported necrotizing granulomatous inflammation. Salmonella species are known to cause true granulomas in bone marrow, liver, and spleen. To the best of our knowledge, true granulomas have not been described in cervical lymph nodes. The aim of this report was to highlight the importance of considering other causative microbiological agents in cases of granulomatous neck abscesses. The patients recovered after receiving treatment with surgical drainage and intravenous antibiotics.

Pyogenic sacroiliitis caused by Salmonella schwarzengrund in a young healthy woman: a case report and literature review

BACKGROUND

Salmonella species are a leading cause of diarrheal diseases worldwide. Recent epidemiological studies have shown that Salmonella schwarzengrund (S. schwarzengrund) is highly prevalent in various regions. Herein, we report that S. schwarzengrund caused sacroiliac joint (SIJ) infection with septic shock in a young woman, although she was immunocompetent.

CASE PRESENTATION

A 20-year-old woman presented with left hip pain, accompanied by vasopressor-requiring hypotension. Her imaging examinations showed fluid collection in her SIJ and a small abscess in the left iliac muscle. Later, the blood and aspiration fluid culture and genetic analysis revealed the presence of S. schwarzengrund. We diagnosed sacroiliac joint (SIJ) infection with septic shock caused by S. schwarzengrund. Her condition improved after performing several interventional radiology (IVR) procedures for SIJ abscesses and providing appropriate antibiotic treatment. Finally, she was discharged without any sequelae. Screening tests and genetic analysis about her immunodeficiency did not indicate a congenital disorder.

CONCLUSION

These clinical courses indicate that S. schwarzengrund could cause the fatal SIJ infection irrespective of the host immunocompetence. Considering the recent increase in the diagnostic rate of S. schwarzengrund, this case emphasized the need to be more cautious about Salmonella species infection.

Non-typhoidal Salmonella bacteremia: comparison of adults and children in a single medical center

Introduction. Non-typhoidal Salmonella (NTS) bacteremia can cause significant morbidity and mortality. There is high incidence of Salmonellosis in the Middle East, including Israel, but there is a paucity of data on the clinical and epidemiological features of children in comparison to adults.Hypothesis/Gap Statement. Previous studies describing the differences between paediatric and adult populations with Salmonella bacteremia are sparse.Aim. This study's aim was to describe the differences between adults and children with NTS bacteremia.Methodology. All records of patients with NTS bacteremia between 1 January 1998 and 31 July 2020 were reviewed. Data regarding clinical manifestations and laboratory results were extracted from the medical records; records of children (aged <18 years) were compared with those of adults.Results. Records for 137 cases of Salmonella bacteremia (69 adults and 68 children, aged 2 days to 98 years) were reviewed. Seventy nine (58 %) patients had concomitant gastrointestinal symptoms. Fifty-eight (84 %) adults and 13 (19 %) children had underlying conditions (P<0.001). Eighteen patients died, none of whom was a child. Over the study period, most of the children (n=46, 67 %) but only five adults were discharged from the emergency department on their first visit to the ED.Conclusions. The main characteristics of NTS bacteremia in children compared to adults, are higher rates of prior discharge from emergency department, higher rate of gastrointestinal symptoms and better prognosis.

Case report: post-salmonellosis abscess positive for Salmonella Oranienburg

Background

Salmonella gastroenteritis is a self-limited infection in immunocompetent adults. Salmonella Oranienburg is a serovar that has recently caused outbreaks of gastroenteritis traced to contact with a pet turtle. Extraintestinal focal infections (EFIs) with invasive Salmonella have been reported uncommonly, examples of which include mycotic aneurysm and spinal osteomyelitis.

Case presentation

The patient is an otherwise healthy 39-year-old male with sleep apnea presenting with pain and swelling in the left anterior chest wall several months after an episode of Salmonella gastroenteritis and bacteremia which was treated successfully with intravenous (IV) antibiotics. He was found to have a costochondral joint abscess with operative cultures positive for S. Oranienburg, a serovar reported to have been associated with pet turtles and onions in recent CDC and FDA news releases. Of note, the joint abscess began development 2–3 months after his episode of Salmonella bacteremia. At the time of surgical treatment, nearly 6 months had passed since the initial episode of gastroenteritis and bacteremia.

Conclusions

Delayed development of a sternocostal joint abscess after Salmonella bacteremia in an otherwise healthy adult male is an unusual presentation. The patient had two different exposures: a fast food chicken lunch and a pet turtle at home. Extraintestinal focal infections with invasive Salmonella are very uncommonly reported in healthy adult patients treated in developed countries. To our knowledge, we report this sequala for the first time.

Invasive non-typhoidal Salmonella infection complicated by metastatic infections: report of three cases

Non-typhoidal Salmonella (NTS) disease is usually a self-limiting infection presenting with digestive symptoms. However, disseminated presentation with involvement of secondary infectious sites is observed. We report diagnostic specificities and challenges related to the management of three patients with invasive NTS (iNTS) and secondary infectious locations. Among the seven patients (age range 46 – 83 years), four (two with extra-digestive infectious sites) had at least one immune debilitating condition. Two patients were incidentally discovered with iNTS and deceased after developing a septic shock despite antimicrobial treatment. Two individuals recovered under medical treatment without complications. Three other patients presented with secondary infectious sites. Case 1 suffered from urinary tract infection and dorsolumbar spondylodiscitis that responded well to antimicrobials and surgery. Abdominal prosthetic aortic aneurysm was diagnosed in case 2 and medical treatment only was applied. After four years of follow-up, he remains under antimicrobial treatment. Case 3 presented with conjoint thoracic aortic aneurysm and cutaneous abscesses managed with antimicrobials and surgery. Atherosclerosis and previous vascular intervention were the predisposing events for vascular involvement. iNTS is a serious disease carrying a high risk of mortality or secondary locations. Secondary locations can be managed by long duration antimicrobial therapy combined with surgery. Spine and aortitis are the most frequent secondary locations. Multi-drug resistant NTS represent an additional risk of mortality. Public health measures should be implemented to limit the spread of NTS to humans and the emergence of drug resistance.

Non-typhoidal Salmonella Bacteremia in COVID-19 with Recrudescence of Fever After Corticosteroid Discontinuation: A case report

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Secondary bacterial infections occur in COVID-19 patients treated with corticosteroid.

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Rebound phenomenon is observed after the cessation of steroid treatment.

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Non-typhoidal Salmonella bacteremia is associated with immunosuppressive conditions.

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Blood cultures distinguish between secondary infections and rebound phenomena.

It is challenging for clinicians to determine the cause of occurrence of fever in COVID-19 patients after corticosteroid discontinuation. Blood cultures help us distinguish between secondary infections and rebound phenomena. We report a case of non-typhoidal Salmonella bacteremia in a 34-year-old male COVID-19 patient who developed fever after discontinuing corticosteroids.

Epidemiology and Outcomes of Nontyphoidal Salmonella Bacteremias from England, 2004 to 2015

Nontyphoidal Salmonella (NTS) bacteremia causes hospitalization and high morbidity and mortality. We linked Gastrointestinal Bacteria Reference Unit (GBRU) data to the Hospital Episode Statistics (HES) data set to study the trends and outcomes of NTS bacteremias in England between 2004 and 2015. All confirmed NTS isolates from blood from England submitted to GBRU between 1 January 2004 and 31 December 2015 were deterministically linked to HES records. Adjusted odds ratios (AOR), proportions, and confidence intervals (CI) were calculated to describe differences in age, sex, antibiotic resistance patterns, and serotypes over time. Males, neonates, and adults above 65 years were more likely to have NTS bacteremia (AOR, 1.54 [95% CI, 1.46 to 1.67]; 2.57 [95% CI, 1.43 to 4.60]; and 3.56 [95% CI, 3.25 to 3.90], respectively). Proportions of bacteremia increased from 1.41% in 2004 to 2.67% in 2015. Thirty-four percent of all blood isolates were resistant to a first-line antibiotic, and 1,397 (56%) blood isolates were linked to an HES record. Of the patients with NTS bacteremia, 969 (69%) had a cardiovascular condition and 155 (12%) patients died, out of which 120 (77%) patients were age 65 years and above. NTS bacteremia mainly affects older people with comorbidities placing them at increased risk of prolonged hospital stay and death. Resistance of invasive NTS to first-line antimicrobial agents appeared to be stable in England, but the emergence of resistance to last-resort antibiotics, such as colistin, requires careful monitoring.

Infectious Aortitis: A Life-Threatening Endovascular Complication of Nontyphoidal Salmonella Bacteremia

A 65-year-old Japanese man living in the United States presented with pyrexia and chills associated with intermittent lower abdominal and back pain for 5 days. He denied recent travel, rash, diarrhea, or rectal bleeding. Physical examination revealed spiking pyrexia, and routine laboratory tests revealed mild leukocytosis and neutrophilia. Abdominal CT with contrast showed findings highly compatible with aortitis. Comprehensive autoimmune evaluation was negative. Salmonella enterica serotype Enteritidis was isolated from blood cultures. IV antibiotics were administered, but the patient continued to experience low-grade pyrexia and mild leukocytosis, and follow-up abdominal CT showed progressive aortic inflammation. The patient therefore underwent resection of the affected aortic segment with in-situ graft replacement and lifelong suppressive antibiotics. The patient is asymptomatic with no complications at 18 weeks of follow-up. This case report illustrates that patients with infectious aortitis from nontyphoidal Salmonella may (1) present with nonspecific and nonlocalizing symptoms and signs except for sepsis; (2) have diagnostic blood cultures and abdominal CT findings; and (3) typically require aggressive, prolonged IV antibiotic therapy and surgery for potential cure of this life-threatening infection.

An Unusual Case of Mycotic Popliteal Aneurysm Presenting as Recurrent Salmonella enteritidis Bacteraemia

We describe a patient with a Salmonella enteritidis mycotic aneurysm. A 91-year-old man presented with recurrent episodes of S. enteritidis bacteraemia 2 months apart. During the second presentation, he underwent magnetic resonance imaging of the left lower limb that revealed rupture of the popliteal artery with a popliteal fossa collection. This was aspirated and cultures grew S. enteritidis. He underwent endovascular stenting and received a prolonged course of antibiotics. Popliteal artery mycotic aneurysm should be considered as a differential in patients presenting with unilateral painful leg swelling and bacteraemia from microorganisms with a propensity for endovascular infections.

SalmoNet, an integrated network of ten Salmonella enterica strains reveals common and distinct pathways to host adaptation

Salmonella enterica is a prominent bacterial pathogen with implications on human and animal health. Salmonella serovars could be classified as gastro-intestinal or extra-intestinal. Genome-wide comparisons revealed that extra-intestinal strains are closer relatives of gastro-intestinal strains than to each other indicating a parallel evolution of this trait. Given the complexity of the differences, a systems-level comparison could reveal key mechanisms enabling extra-intestinal serovars to cause systemic infections. Accordingly, in this work, we introduce a unique resource, SalmoNet, which combines manual curation, high-throughput data and computational predictions to provide an integrated network for Salmonella at the metabolic, transcriptional regulatory and protein-protein interaction levels. SalmoNet provides the networks separately for five gastro-intestinal and five extra-intestinal strains. As a multi-layered, multi-strain database containing experimental data, SalmoNet is the first dedicated network resource for Salmonella. It comprehensively contains interactions between proteins encoded in Salmonella pathogenicity islands, as well as regulatory mechanisms of metabolic processes with the option to zoom-in and analyze the interactions at specific loci in more detail. Application of SalmoNet is not limited to strain comparisons as it also provides a Salmonella resource for biochemical network modeling, host-pathogen interaction studies, drug discovery, experimental validation of novel interactions, uncovering new pathological mechanisms from emergent properties and epidemiological studies. SalmoNet is available at http://salmonet.org.

Carbuncle due to Salmonella Enteritidis: a novel presentation

Background

Salmonella Enteritidis causes intestinal and extra-intestinal infections, but rarely cutaneous infections. It has never been reported to cause carbuncle (a collection of interconnected furuncles with multiple pustular openings). We report a case of carbuncle due to S. Enteritidis.

Case presentation

An adult Bangladeshi patient with type 2 diabetes presented with a carbuncle on the left-side of his neck. A pure culture of S. Enteritidis was grown from the pus of the carbuncle. The patient was successfully treated with ciprofloxacin to which the isolate was susceptible. Whole genome sequencing of the strain showed that it possessed three additional virulence genes—pef (for plasmid-encoded fimbriae), spv (for salmonella plasmid virulence), rck (for resistance to complement killing) -responsible for systemic infections that were absent in the genome of a reference S. Enteritidis strain. In phylogenetic analysis, the strain clustered with other S. Enteritidis strains from different parts of the world.

Conclusions

A weakened immune system of the patient due to diabetes mellitus and the additional virulence genes of the isolate may have contributed to the unusual presentation of carbuncle. The possibility of S. Enteritidis to cause carbuncle should be considered.

Electronic supplementary material

The online version of this article (doi:10.1186/s13099-017-0200-2) contains supplementary material, which is available to authorized users.

Urinary Tract Infections Due to Nontyphoidal Salmonella

BACKGROUND

We sought to establish the characteristics of symptomatic nontyphoidal Salmonella (NTS) urinary tract infection (UTI) without concomitant gastroenteritis (GE) as a separate clinical entity.

MATERIALS AND METHODS

We conducted a retrospective cohort single-center study and reviewed all cases of NTS bacteriuria between 1995 and 2016. Patients were assigned to a group according to their clinical presentation, namely, symptomatic NTS UTI without GE, GE with NTS bacteriuria or isolated asymptomatic NTS bacteriuria. We compared the characteristics of patients in the NTS UTI group to those of the latter 2 groups.

RESULTS

NTS bacteriuria was found in 77 patients, of which 61 had records available for review. Twenty-one patients (including 17 adults) presented with NTS UTI, 30 patients presented with features of GE with NTS bacteriuria and 10 patients had asymptomatic NTS bacteriuria. NTS UTI was not significantly associated with older age, male sex, diabetes, immunosuppressive states or urologic abnormalities. There was a significant difference in the proportion of patients with an underlying urologic malignancy in the NTS UTI group (4 of 17 patients [23.5%]) as compared to those in the other groups (0 of 24 patients), P = 0.023.

CONCLUSIONS

A unique group of patients with symptomatic NTS UTI without GE was identified. A significant association with urologic malignancies was demonstrated in patients with NTS UTI compared to those with GE and NTS bacteriuria or asymptomatic NTS bacteriuria.

An unusual case of Salmonella Enteritidis causing pneumonia, septic shock and multiple organ failure in an immunocompetent patient

Salmonella species are facultative intracellular pathogens that most frequently cause self-limiting gastrointestinal disease, often acquired through the ingestion of contaminated food. We report the case of a 33-year-old otherwise healthy, not overtly immunosuppressed, man who was transferred to our facility with the chief complaint of respiratory failure and septic shock. Computed tomography of the chest revealed multifocal pneumonia in both lungs. A bronchial alveolar lavage was performed in the right middle lobe and cultures predominantly grew Salmonella enterica serovar Enteritidis. The patient received a prolonged course of antimicrobials, ultimately changing to oral levofloxacin. The etiology of the salmonella infection likely occurred through an aspiration event. Salmonella species are not a typical respiratory pathogen in immunocompetent hosts; however, clinicians should be aware of the possibility that salmonella species may be a pathogenic source of infection in the lungs; a prolonged course of antimicrobials may be warranted.

First Case of Lung Abscess due to Salmonella enterica Serovar Abony in an Immunocompetent Adult Patient

In healthy individuals, nontyphoidal Salmonella species predominantly cause a self-limited form of gastroenteritis, while they infrequently invade or cause fatal disease. Extraintestinal manifestations of nontyphoidal Salmonella infections are not common and mainly occur among individuals with specific risk factors; among them, focal lung infection is a rare complication caused by nontyphoidal Salmonella strains typically occurring in immunocompromised patients with prior lung disease. We describe the first case of a localized lung abscess formation in an immunocompetent healthy female adult due to Salmonella enterica serovar Abony. The patient underwent lobectomy and was discharged after full clinical recovery. This case report highlights nontyphoidal Salmonellae infections as a potential causative agent of pleuropulmonary infections even in immunocompetent healthy adults.

Emergence of a Clonal Lineage of Multidrug-Resistant ESBL-Producing Salmonella Infantis Transmitted from Broilers and Broiler Meat to Humans in Italy between 2011 and 2014

We report the spread of a clone of multidrug-resistant (MDR), ESBL-producing (blaCTX-M-1) Salmonella enterica subsp. enterica serovar Infantis, in the Italian broiler chicken industry and along the food-chain. This was first detected in Italy in 2011 and led to human infection in Italy in 2013-2014.A set (n = 49) of extended-spectrum cephalosporin (ESC)-resistant (R) isolates of S. Infantis (2011-2014) from humans, food-producing animals and meat thereof, were studied along with a selected set of earlier and more recent ESC-susceptible (ESC-S) isolates (n = 42, 2001-2014). They were characterized by macrorestriction-PFGE analysis and genetic environment of ESC-resistance. Isolates representative of PFGE-patterns and origin were submitted to Whole Genome Sequencing. The emerging ESC-R clone, detected mainly from broiler chickens, broiler meat and humans, showed a minimum pattern of clinical resistance to cefotaxime, tetracycline, sulfonamides, and trimethoprim, beside ciprofloxacin microbiological resistance (MIC 0.25 mg/L). All isolates of this clone harbored a conjugative megaplasmid (~ 280-320 Kb), similar to that described in ESC-susceptible S. Infantis in Israel (pESI-like) in 2014. This megaplasmid carried the ESBL gene blaCTX-M-1, and additional genes [tet(A), sul1, dfrA1 and dfrA14] mediating cefotaxime, tetracycline, sulfonamide, and trimethoprim resistance. It also contained genes conferring enhanced colonization capability, virulence (fimbriae, yersiniabactin), resistance and fitness (qacE1, mer) in the intensive-farming environment. This emerging clone of S. Infantis has been causing infections in humans, most likely through the broiler industry. Since S. Infantis is among major serovars causing human infections in Europe and is an emerging non-typhoidal Salmonella globally, further spread of this lineage in primary productions deserves quick and thorough risk-management strategies.

The Stringent Response Regulator DksA Is Required for Salmonella enterica Serovar Typhimurium Growth in Minimal Medium, Motility, Biofilm Formation, and Intestinal Colonization

Salmonella enterica serovar Typhimurium is a facultative intracellular human and animal bacterial pathogen posing a major threat to public health worldwide. Salmonella pathogenicity requires complex coordination of multiple physiological and virulence pathways. DksA is a conserved Gram-negative regulator that belongs to a distinct group of transcription factors that bind directly to the RNA polymerase secondary channel, potentiating the effect of the signaling molecule ppGpp during a stringent response. Here, we established that in S. Typhimurium, dksA is induced during the logarithmic phase and DksA is essential for growth in minimal defined medium and plays an important role in motility and biofilm formation. Furthermore, we determined that DksA positively regulates the Salmonella pathogenicity island 1 and motility-chemotaxis genes and is necessary for S. Typhimurium invasion of human epithelial cells and uptake by macrophages. In contrast, DksA was found to be dispensable for S. Typhimurium host cell adhesion. Finally, using the colitis mouse model, we found that dksA is spatially induced at the midcecum during the early stage of the infection and required for gastrointestinal colonization and systemic infection in vivo. Taken together, these data indicate that the ancestral stringent response regulator DksA coordinates various physiological and virulence S. Typhimurium programs and therefore is a key virulence regulator of Salmonella.

Virulence diversity among bacteremic Aeromonas isolates: ex vivo, animal, and clinical evidences

Background

The objective of this study was to compare virulence among different Aeromonas species causing bloodstream infections.

Methodology/Principal Findings

Nine of four species of Aeromonas blood isolates, including A. dhakensis, A. hydrophila, A. veronii and A. caviae were randomly selected for analysis. The species was identified by the DNA sequence matching of rpoD. Clinically, the patients with A. dhakensis bacteremia had a higher sepsis-related mortality rate than those with other species (37.5% vs. 0%, P = 0.028). Virulence of different Aeromonas species were tested in C. elegans, mouse fibroblast C2C12 cell line and BALB/c mice models. C. elegans fed with A. dhakensis and A. caviae had the lowest and highest survival rates compared with other species, respectively (all P values <0.0001). A. dhakensis isolates also exhibited more cytotoxicity in C2C12 cell line (all P values <0.0001). Fourteen-day survival rate of mice intramuscularly inoculated with A. dhakensis was lower than that of other species (all P values <0.0001). Hemolytic activity and several virulence factor genes were rarely detected in the A. caviae isolates.

Conclusions/Significance

Clinical data, ex vivo experiments, and animal studies suggest there is virulence variation among clinically important Aeromonas species.

Time to positivity in blood cultures of adults with nontyphoidal Salmonella bacteremia

BACKGROUND

Nontyphoidal Salmonella (NTS) is an important bacterial etiology of diarrheal disease, and it causes invasive diseases in immunocompromised hosts. For bacteremia from some species, blood culture with a rapid time to positivity (TTP) is associated with greater mortality. This study investigated TTP of NTS bacteremia and its relationship to clinical parameters and prognosis.

METHODS

Adult patients with NTS bacteremia who were admitted to a tertiary care facility in northern Taiwan from January 2010 to December 2012 were enrolled. Demographics, clinical and microbiological characteristics, and treatment response were reviewed. The TTP for each patient was retrieved from the automated machine.

RESULTS

Sixty-six adult patients (mean age, 66.1 years; range, 27-96 years) with NTS bacteremia were identified by the following serogroup distributions: serogroup B (23.4%), serogroup C1 (1.6%), serogroup C2 (6.3%), and serogroup D (68.8%). The in-hospital mortality, 14-day mortality, and 30-day mortality were 15.2%, 7.6%, and 12.1%, respectively. The TTP ranged 6.5-41.7 hours (median: 11.5 hours). Patients with rapid TTP (less than 10 hours), compared to patients without rapid TTP, were more likely to have liver cirrhosis (31.6% vs. 6.4%, p = 0.013), endovascular lesions (21.1% vs. 4.3%, p = 0.05), higher bacteremia score, intensive care unit admission (57.9% vs. 25.5%, p = 0.021), and septic shock (63.2% vs. 12.8%, p < 0.001). There were no significant differences in the in-hospital mortality and 14-day mortality between patients with TTP <10 hours and patients with TTP ≥10 hours.

CONCLUSION

The TTP of blood cultures, interpreted with a cut-off point of <10 hours, in patients with NTS bacteremia may provide useful diagnostic and prognostic information.

Nontyphoidal salmonella urinary tract infection in a case of hyperparathyroidism and nephrocalcinosis

Nontyphoidal Salmonella infections often present with self-limited gastroenteritis. Extraintestinal focal infections are uncommon but have high mortality and morbidity. Urinary tract infection caused by nontyphoidal Salmonella is usually associated with structural abnormalities of the urinary tract. Nephrocalcinosis and nephrolithiasis are the major risk factors. Although primary hyperparathyroidism has been reported to increase the risk of nephrocalcinosis and nephrolithiasis, little is known about the association between hyperparathyroidism and Salmonella urinary tract infection. We report the case of a 37-year old man who had a history of primary hyperparathyroidism and bilateral nephrocalcinosis and who developed urinary tract infection. Salmonella Group D was isolated from his urine specimen. Salmonella should be considered as a possible causality organism in patients with primary hyperparathyroidism and nephrocalcinosis who develop urinary tract infection. These patients need to be aware of the potential risks associated with salmonellosis.

A unique megaplasmid contributes to stress tolerance and pathogenicity of an emergent Salmonella enterica serovar Infantis strain

Of all known Salmonella enterica serovars, S. Infantis is one of the most commonly isolated and has been recently emerging worldwide. To understand the recent emergence of S. Infantis in Israel, we performed extensive comparative analyses between pre-emergent and the clonal emergent S. Infantis populations. We demonstrate the fixation of adaptive mutations in the DNA gyrase (gyrA) and nitroreductase (nfsA) genes, conferring resistance to quinolones and nitrofurans, respectively, and the carriage of an emergent-specific plasmid, designated pESI. This self-transferred episome is a mosaic megaplasmid (∼280 kb), which increases bacterial tolerance to environmental mercury (mer operon) and oxidative stress, and provides further resistance to tetracycline, sulfamethoxazole and trimethoprim, most likely due to the presence of tetRA, sulI and dfrA genes respectively. Moreover, pESI carries the yersiniabactin siderophore system and two novel chaperone-usher fimbriae. In vitro studies established that pESI conjugation into a plasmidless S. Infantis strain results in superior biofilm formation, adhesion and invasion into avian and mammalian host cells. In vivo mouse infections demonstrated higher pathogenicity and increased intestinal inflammation caused by an S. Infantis strain harboring pESI compared with the plasmidless parental strain. Our results indicate that the presence of pESI that was found only in the emergent population of S. Infantis in Israel contributes significantly to antimicrobials tolerance and pathogenicity of its carrier. It is highly likely that pESI plays a key role in the successful spread of the emergent clone that replaced the local S. Infantis community in the short time of only 2-3 years.

Salmonella typhimurium abscess of the chest wall

Patient: Male, 73

Final Diagnosis: Salmonella typhimurium abscess of the chest wall

Symptoms: —

Medication: Ciprofloxacin

Clinical Procedure:—

Specialty: Infectious Diseases

Cervical Lymphadenitis Caused by Group D Non-typhoidal Salmonella Associated with Concomitant Lymphoma

Non-typhoidal Salmonella species are important foodborne pathogens that can cause gastroenteritis, bacteremia, and subsequent focal infections. Non-typhoidal salmonellosis is problematic, particularly in immunocompromised hosts. Any anatomical site can be affected by this pathogen via hematogenous seeding and may develop local infections. However, cervical lymphadenitis caused by non-typhoidal Salmonella species is rarely reported. Herein, we have reported a case of cervical lymphadenitis caused by group D non-typhoidal Salmonella associated with lymphoma.

Salmonella mycotic thoracoabdominal aortic aneurysm associated with chronic lymphocytic leukemia

Non-typhoidal Salmonella infections typically cause self-limiting gastroenteritis. However, extraintestinal focal infections, including mycotic aneurysms of the aorta, can also occur. We present the case of a 71-year-old man with chronic lymphocytic leukemia (CLL) and a large type V thoracoabdominal mycotic aneurysm infected with Salmonella enteritidis, complicated by thoracolumbar spondylodiscitis, paravertebral collections, and epidural abscess. This is the first report of Salmonella aortitis in the setting of CLL, and the unusual extent of local infective invasion seen here with Salmonella enteritidis infection raises a suspicion of CLL-related immunosuppression as a direct predisposing factor. This case illustrates the need to consider the possibility of an immune defect, even in CLL patients with normal leukocyte counts. The underlying mechanisms are unclear, but are likely to involve defects in cell-mediated immunity, thought to be of particular importance in invasive infections with intracellular pathogens such as Salmonella spp.

Antimicrobials for treating symptomatic non-typhoidal Salmonella infection

BACKGROUND

Non-typhoidal Salmonella (NTS) commonly causes diarrhoea, and is usually self-limiting, although sometimes people become ill with sepsis and dehydration. Routine antibiotic use for this infection could result in persistent colonization and the spread of resistant bacterial strains.

OBJECTIVES

To assess the efficacy and safety of giving antibiotics to people with NTS diarrhoea.

SEARCH METHODS

We searched the Cochrane Infectious Diseases Group trials register (up to August 2012), the Cochrane Controlled Trials Register (CENTRAL) published in The Cochrane Library (up to Issue 8 2012); and MEDLINE, African Index Medicus, CINAHL, EMBASE, LILACS, and the Science Citation Index, all up to 6 August 2012. We also searched the metaRegister of Controlled Trials (mRCT) for both completed and on going trials and reference lists of relevant articles.

SELECTION CRITERIA

Randomized controlled trials (RCTs) comparing any antibiotic treatment for diarrhoea caused by NTS species with placebo or no antibiotic treatment. We selected trials that included people of all ages who were symptomatic for NTS infection. Examples of symptoms included fever, abdominal pain, vomiting and diarrhoea. We excluded trials where the outcomes were not reported separately for the NTS subgroup of patients. Two review authors independently applied eligibility criteria prior to study inclusion.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data on pre-specified outcomes and independently assessed the risk of bias of included studies. The primary outcome was the presence of diarrhoea between two to four days after treatment. The quality of evidence was assessed using the GRADE methods.

MAIN RESULTS

Twelve trials involving 767 participants were included. No differences were detected between the antibiotic and placebo/no treatment arms for people with diarrhoea at two to four days after treatment (risk ratio (RR) 1.75, 95% confidence interval (CI) 0.42 to 7.21; one trial, 46 participants; very low quality evidence). No difference was detected for the presence of diarrhoea at five to seven days after treatment (RR 0.83, 95% CI 0.62 to 1.12; two trials, 192 participants; very low quality evidence), clinical failure (RR 0.88, 95% CI 0.62 to 1.25; seven trials, 440 participants; very low quality evidence). The mean difference for diarrhoea was 0 days (95% CI -0.54 to 0.54; 202 participants, four studies; low quality evidence);for fever was 0.27 days (95% CI -0.11 to 0.65; 107 participants, two studies; very low quality evidence); and for duration of illness was 0 days (95% CI -0.68 to 0.68; 116 participants, two studies; very low quality evidence). Quinolone antibiotic treatment resulted in a significantly higher number of negative stool cultures for NTS during the first week of treatment (microbiological failure: RR 0.33, 95% CI 0.20 to 0.56; 166 participants, four trials).Antibiotic treatment meant passage of the same Salmonella serovar one month after treatment was almost twice as likely (RR 1.96, 95% CI 1.29 to 2.98; 112 participants, three trials), which was statistically significant. Non-severe adverse drug reactions were more common among the patients who received antibiotic treatment.

AUTHORS' CONCLUSIONS

There is no evidence of benefit for antibiotics in NTS diarrhoea in otherwise healthy people. We are uncertain of the effects in very young people, very old people, and in people with severe and extraintestinal disease. A slightly higher number of adverse events were noted in people who received antibiotic treatment for NTS.

Live attenuated S. Typhimurium vaccine with improved safety in immuno-compromised mice

Live attenuated vaccines are of great value for preventing infectious diseases. They represent a delicate compromise between sufficient colonization-mediated adaptive immunity and minimizing the risk for infection by the vaccine strain itself. Immune defects can predispose to vaccine strain infections. It has remained unclear whether vaccine safety could be improved via mutations attenuating a vaccine in immune-deficient individuals without compromising the vaccine's performance in the normal host. We have addressed this hypothesis using a mouse model for Salmonella diarrhea and a live attenuated Salmonella Typhimurium strain (ssaV). Vaccination with this strain elicited protective immunity in wild type mice, but a fatal systemic infection in immune-deficient cybb^−/−nos2^−/− animals lacking NADPH oxidase and inducible NO synthase. In cybb^−/−nos2^−/− mice, we analyzed the attenuation of 35 ssaV strains carrying one additional mutation each. One strain, Z234 (ssaV SL1344_3093), was >1000-fold attenuated in cybb^−/−nos2^−/− mice and ≈100 fold attenuated in tnfr1^−/− animals. However, in wt mice, Z234 was as efficient as ssaV with respect to host colonization and the elicitation of a protective, O-antigen specific mucosal secretory IgA (sIgA) response. These data suggest that it is possible to engineer live attenuated vaccines which are specifically attenuated in immuno-compromised hosts. This might help to improve vaccine safety.

Non-typhoidal Salmonella bacteraemia in elderly patients: an increased risk for endovascular infections, osteomyelitis and mortality

Non-typhoidal Salmonella (NTS) is a common pathogen causing foodborne infections, bacteraemia, and extra-intestinal focal infections (EFIs) in humans. The study compares the clinical characteristics of elderly patients with NTS bacteraemia with those of young adults. Of 272 adults with NTS bacteraemia identified in this study, 162 (59·6%) were aged ⩾55 years. EFIs were observed in 36% of the 162 patients. The most common EFIs in the elderly patients (⩾55 years) was mycotic aneurysm, followed by pulmonary infections and bone/joint infections. Elderly patients more often had chronic heart, lung, renal and malignant diseases, had more EFIs, and a higher 30-day mortality rate. Independent factors of 30-day mortality in elderly patients were solid-organ tumour [adjusted odds ratio (aOR) 4·4, P=0·003], mycotic aneurysm (aOR 3·7, P=0·023) and shock (aOR 12·1, P<0·0001). HIV infection, autoimmune diseases, and receipt of immunosuppressive therapy were more often observed in young patients.

The occurrence and prevention of foodborne disease in vulnerable people

In developed countries, such as the United Kingdom and the United States, between 15% and 20% of the population show greater susceptibility than the general population to foodborne disease. This proportion includes people with primary immunodeficiency, patients treated with radiation or with immunosuppressive drugs for cancer and diseases of the immune system, those with acquired immune-deficiency syndrome and diabetics, people suffering from liver or kidney disease or with excessive iron in the blood, pregnant women, infants, and the elderly. Malnutrition and use of antacids, particularly proton-pump inhibitors, also increase susceptibility. We review the occurrence of infection by foodborne pathogens in these groups of people and measures to prevent infection. The nature and use of low microbial diets to reduce the risk of foodborne disease in immunocompromised patients are very variable. Diets for vulnerable people in care should exclude higher-risk foods, and vulnerable people in the community should receive clear advice about food safety, in particular avoidance of higher-risk foods and substitution of safer, nutritious foods.

Non-typhoidal Salmonella bacteraemia: epidemiology, clinical characteristics and its' association with severe immunosuppression

Background

Non-typhoidal Salmonella (NTS) is increasingly recognized as an important pathogen associated with bacteraemia especially in immunosuppressed patients. However, there is limited data specifically describing the clinical characteristics and outcome amongst the immunosuppressed patients.

Methods

A total of 56,707 blood culture samples and 5,450 stool samples were received by the microbiology laboratory at a tertiary referral hospital in Malaysia, during a 4-year study period. Out of these samples, 55 non-duplicate NTS isolates were identified from blood and 121 from stool. A retrospective analysis of the 55 patients with NTS bacteraemia was then conducted to determine the predominant NTS serovars causing bacteraemia and its' blood invasive potential, epidemiological data, clinical characteristics and antimicrobial susceptibility. Patients were then grouped as immunosuppressed and non-immunosuppressed to determine the association of severe immunosuppression on clinical features. Data was analyzed using the Statistical Package for Social Sciences (SPSS version 15.0) using the non-parametric Mann-Whitney test, Fisher's exact test or Chi-squared test. The odds ratio (OR) and its 95% confidence intervals (CI) were calculated. The P-value < 0.05 (two-tailed) was taken as the level of significance.

Results

Out of 55 NTS bacteraemia cases identified, 81.8% (45/55) were community-acquired. Salmonella enterica serovar Enteritidis had the highest blood invasiveness. An extra-intestinal focus of infection was noted in 30.9% (17/55) of the patients, most commonly involving the lungs and soft tissue. 90.9% (50/55) of the patients had an underlying disease and 65.5% (36/55) of the patients had severe clinical immunosuppressive condition with malignancy and HIV being the most common. Immunosuppressed patients had higher mortality (P = 0.04), presented more commonly with primary bacteraemia (P = 0.023), leukopenia (P = 0.001) and opportunistic infections (P = 0.01). In contrast, atherosclerotic conditions (P = 0.015), mycotic aneurysms (0.037) and gastroenteritis (P = 0.03), were significantly more common in the non-immunosuppressed patients. The non-immunosuppressed group also had a higher proportion of older patients (>50 years) with a significantly higher median age (64 versus 36.5 years; p = 0.005).

Conclusion

Patients with severe clinical immunosuppression had higher mortality, presented more commonly with primary bacteraemia, leukopenia and opportunistic infections and absence of gastroenteritis. Early identification and prompt medical treatment can be life saving because of the high mortality and morbidity associated with this disease especially in the immunosuppressed patients.

Salmonella infections in immunocompromised adults

Clinical syndromes caused by Salmonella infection in humans are divided into typhoid fever, caused by Salmonella typhi and Salmonella paratyphi, and a range of clinical syndromes, including diarrhoeal disease, caused by a large number of non-typhoidal salmonella serovars (NTS). Typhoid is a human-restricted and highly adapted invasive disease, but shows little association with immunocompromise. In contrast, NTS have a broad vertebrate host range, epidemiology that often involves food animals, and have a dramatically more severe and invasive presentation in immunocompromised adults, in particular in the context of HIV. Immunocompromise among adults, including underlying severe or progressive disease, chronic granulomatous disease, defects or blockade of specific cytokines (particularly IL-12/IL-23/IL-17 and TNF), and HIV, is associated with suppurative foci and with primary bacteraemic disease, which may be recurrent. These patients have markedly increased mortality. Worldwide, invasive recurrent NTS bacteraemia associated with advanced HIV disease is a huge problem, and the epidemiology in this context may be more human-restricted than in other settings. This review will describe the presentation and pathogenesis of NTS in different categories of immunocompromised adults, contrasted to typhoid fever.

Short- and long-term effects of bacterial gastrointestinal infections

Bacterial gastrointestinal infections are associated with short- and long-term complications from several organ systems.

During 1997–2004, microbiologically confirmed gastrointestinal infections were reported for 101,855 patients in Sweden. Among patients who had Salmonella infection (n = 34,664), we found an increased risk for aortic aneurysm (standardized incidence ratio [SIR] 6.4, 95% confidence interval [CI] 3.1–11.8) within 3 months after infection and an elevated risk for ulcerative colitis (SIR 3.2, 95% CI 2.2–4.6) within 1 year after infection. We also found this elevated risk for ulcerative colitis among Campylobacter infections (n = 57,425; SIR 2.8, 95% CI 2.0–3.8). Within 1 year, we found an increased risk for reactive arthritis among patients with Yersinia enteritis (n = 5,133; SIR 47.0, 95% CI 21.5–89.2), Salmonella infection (SIR 18.2, 95% CI 12.0–26.5), and Campylobacter infection (SIR 6.3, 95% CI 3.5–10.4). Acute gastroenteritis is sometimes associated with disease manifestations from several organ systems that may require hospitalization of patients.

Herpes simplex virus colitis complicating ulcerative colitis: A case report and brief review on superinfections

In patients with inflammatory bowel disease herpes simplex virus infection has been described as a major cause of morbidity and mortality, especially in immunocompromised individuals. Here we present the case of a 35-year old woman with an exacerbation of ulcerative colitis caused by herlpes simplex virus infection (HSV-2). The diagnosis was confirmed histologically following subtotal colectomy. After intravenous treatment with aciclovir for 2 weeks postoperative hematochezia stopped. Herpes simplex virus colitis is a rare but potentially fatal complication of immunosuppressive treatment in patients with inflammatory bowel disease. Prompt diagnosis and efficient antiviral therapy are mandatory to improve prognosis.