Risk factors for primary bacteremia and endovascular infection in patients without acquired immunodeficiency syndrome who have nontyphoid salmonellosis

Phenotypic and Molecular Characterization of a Hospital Outbreak Clonal Lineage of Salmonella enterica Subspecies enterica serovar Mikawasima Containing blaTEM-1B and blaSHV-2 That Emerged on a Neonatal Ward, During the COVID-19 Pandemic

Nontyphoid salmonella can cause severe infections in newborns and is therefore declared a pathogen of major health significance at this age. The aim of the study was molecular and antimicrobial characterization of β-lactamase-producing Salmonella Mikawasima outbreak clone on a Neonatal ward, University Hospital of Split (UHS), Croatia during the COVID-19 pandemic. From April 2020, until April 2023, 75 nonrepetitive strains of Salmonella Mikawasima were isolated from stool specimens and tested for antimicrobial resistance. All 75 isolates were resistant to ampicillin and gentamicin, while 98% of isolates were resistant to amoxicillin/clavulanic acid. A high level of resistance was observed to third-generation cephalosporins (36% to ceftriaxone and 47% to ceftazidime). Extended-spectrum β-lactamase production was phenotypically detected by double-disk synergy test in 40% of isolates. Moderate resistance to quinolones was detected; 7% of isolates were resistant to pefloxacin and ciprofloxacin. All isolates were susceptible to carbapenems, chloramphenicol, and co-trimoxazole. Fourteen representative isolates, from 2020, 2021, 2022, and 2023, were analyzed with PFGE and all of them belong to the same clone. Whole-genome sequencing (WGS) analysis of three outbreak-related strains (SM1 and SM2 from 2020 and SM3 from 2023) confirmed that these strains share the same serotype (Mikawasima), multilocus sequence typing profile (ST2030), resistance genes [blaTEM-1B, aac(6')-Iaa, aac(6')-Im, and aph(2'')-Ib)] and carry incompatibility group C (IncC) plasmid. Furthermore, the gene blaSHV-2 was detected in SM1 and SM2. In summary, WGS analysis of three representative strains clearly demonstrates the persistence of β-lactamase-producing Salmonella Mikawasima in UHS during the 4-year period.

Gallbladder Empyema and Epidural Abscess Due to Salmonella Enteritidis After Treatment of Primary Infection: Case Report and Review of the Literature

Nontyphoidal Salmonella can cause gallbladder empyema and disseminated disease in patients with suppressed immune systems. We are reporting a unique case of concomitant gallbladder empyema and epidural abscess due to Salmonella enterica subsp enterica serovar Enteritidis in a patient who was appropriately treated for the primary Salmonella infection complicated by bacteremia. A high degree of suspicion is needed in high-risk patients as timely intervention can avoid life-threatening complications.

Increased non-typhoidal Salmonella hospitalizations in transfusion-naïve thalassemia children: a nationwide population-based cohort study

INTRODUCTION

Although non-typhoidal Salmonella (NTS) infection usually causes self-limited enterocolitis, several risk factors have been found to predispose individuals to more severe NTS infections. However, few studies have discussed the association between NTS infection and pediatric thalassemia populations.

MATERIAL AND METHODS

A nationwide population-based retrospective cohort study was conducted using medical records of the selected children from the Taiwan National Health Insurance Research Database. Immunocompromised individuals or patients with a history of transfusion or splenectomy were excluded. One thalassemia patient was matched with four non-thalassemia patients based on their year of birth, sex, and urbanization level.

RESULTS

In this cohort, 912 patients with thalassemia and 3648 comparison cohort were analyzed. The mean age of NTS hospitalization was 2.0 ± 1.4 in thalassemia cohort and 2.6 ± 2.4 in non-thalassemia cohort. Transfusion-naïve thalassemia children were proved to have a higher rate of NTS hospitalization (6.90 vs 4.11 per 1000 person-year; p = 0.0004) than the non-thalassemia cohort, with an adjusted hazard ratio (HR) of 1.68 (95% confidence interval [CI] = 1.26-2.24).

CONCLUSION

Our research shows that transfusion-naïve thalassemia is associated with an increased risk of NTS hospitalization. Further prospective study comparing the incidence and severity of NTS infection among children with and without thalassemia is needed.

IMPACT

Pediatric transfusion-naïve thalassemia patients have an 1.68-fold increased risk for hospitalization due to non-typhoidal Salmonella (NTS) infection. This is the first nationwide population-based cohort study based on an extremely large database that shows pediatric transfusion-naïve thalassemia patients have an increased risk for NTS hospitalizations. Besides the previously known risk factors such as extremes of age, sickle cell disease, or immunosuppressing conditions, clinicians must also take thalassemia as a possible risk factor for more severe NTS disease.

Clinical and epidemiological features in hospitalized young children with acute gastroenteritis in Taiwan: A multicentered surveillance through 2014-2017

BACKGROUND/PURPOSE

Acute gastroenteritis (AGE) remains a significant health issue in children. The worldwide evolution of pediatric AGE pathogens had been recorded since the introduction of rotavirus vaccine. Ten years after the rotavirus vaccine was introduced to the private sectors in Taiwan, a nationwide study was conducted to elucidate the epidemiological changes among major AGE pathogens.

METHODS

From January 2014 to December 2017, children younger than 5 years old, hospitalized with AGE at 10 hospitals across Taiwan were enrolled. Stool specimens were tested for Salmonella spp., Campylobacter spp., Clostridiodes difficile, norovirus, and rotavirus by polymerase chain reaction (PCR). The epidemiological and clinical information was collected.

RESULTS

Enteric pathogen were detected in 1983 (42.2%) of 4700 subjects, with Salmonella spp. (12.5%) being the leading cause of AGE, followed by norovirus (11.2%), rotavirus (8.7%), C. difficile (4.2%), Campylobacter spp. (1.0%), and a mixture of at least 2 of 5 above-mentioned pathogens (4.6%). The case distributions varied across different regions. In eastern Taiwan, rotavirus (21/131, 16.0%) remained the most common pathogen detected. The rotavirus vaccine uptake rate is significantly lower in patients with rotavirus AGE. Besides, rotavirus AGE frequently occurred in children with foreign parent(s), Taiwanese indigenous people, and those with the household monthly income < NT$ 60,000.

CONCLUSION

Salmonella spp. and norovirus were two major pathogens of pediatric AGE in Taiwan during 2014-17. Providing low-to middle-income households with free rotavirus vaccine nationwide and an industry-led act to reduce salmonellosis should be considered by the authorities.

Risk of non-typhoidal Salmonella vascular infections is increased with degree of atherosclerosis and inflammation: A multicenter study in southern Taiwan

BACKGROUND

Atherosclerosis and vascular inflammatory response have been considered as risk factors for non-typhoidal Salmonella (NTS) vascular infection. The study aims to assess the risk of vascular infection by measuring atherosclerosis severity, NTS vascular infection (NTSVI) score, and serum levels of inflammatory markers in people with NTS bacteremia.

METHODS

A prospective observational study was conducted in two medical centers and two regional hospitals. Adults aged ≥50 years with NTS bacteremia who underwent computed tomography (CT) scan for revealing vascular infections were enrolled. The degree of atherosclerosis was scaled by a calcium score determined by a CT scan. Serum concentrations of inflammatory biomarkers were determined in the patients enrolled in a medical center.

RESULTS

Fourteen (20.3%) of 69 patients with NTS bacteremia had vascular infections. Calcium scores over the thoracic (12,540 vs. 3,261, P = 0.0005) and abdominal (9755 vs. 3,461, P = 0.0006) aorta of those with vascular infections were higher than those without vascular infection. All vascular infections were present in the high-risk group (NTSVI score ≥1), yielding a sensitivity of 100% and specificity of 30.9%. Among 17 low-risk patients (NTSVI score <1), none had vascular infections, resulting in a negative predictive value of 100%. Higher plasma concentrations of IL-1β were detected in the cases of vascular infection than those in the control group (23.6 vs. 1.06 pg/mL, P = 0.001).

CONCLUSION

Atherosclerosis of the aorta which is associated with a positive NTSVI score can predict the occurrence of vascular infections and serum IL-1β could be a biomarker for vascular infection in patients with NTS bacteremia.

Salmonella enterica serovars associated with bacteremia in Canada, 2006-2019

Background

Members of the bacterial genus Salmonella cause salmonellosis, a disease with a spectrum of clinical presentations from a self-limiting gastroenteritis to more severe bacteremia, organ failure and sepsis. The genus consists of over 2,600 serological variants (serovars). Important differences in the pathogenesis of Salmonella serovars have been noted.

Objective

The purpose of this study was to determine which Salmonella serovars were more likely to be associated with bacteremia in Canada.

Methods

Information on the total number of Salmonella infections and blood isolations reported to the National Enteric Surveillance Program (NESP) from 2006 to 2019 was extracted for each serovar. The risk (proportion) and likelihood (odds) of bacteremia were calculated for all serovars.

Results

Of the 96,082 Salmonella cases reported to the NESP during the 14-year study period, 4.4% (95% CI: 4.3%-4.6%) were bacteremic. Twenty nontyphoidal Salmonella (NTS) serovars were associated with lower rates of bacteremia compared to all NTS serovars, and 19 NTS serovars were identified as having higher rates. Heidelberg, Oranienburg, Schwarzengrund, Virchow, Panama and Poona among the top 25 most commonly reported serovars in Canada during the study period.

Conclusion

The identification of serovars associated with Salmonella bacteremia in Canada is a first step towards understanding differences in pathogenesis and disease presentation.

An Unusual Case of Streptococcus pyogenes Causing Ruptured Aortic Mycotic Aneurysm

A 70-year-old male with a complex past medical history presents with confusion and slurred speech for 24 hours. His exam was unremarkable, and his CT head was negative. Both his C-reactive protein and white blood cell count were elevated. As part of the delirium workup, blood cultures were done which grew Streptococcus pyogenes with no obvious source. He was treated with appropriate antibiotics. To determine the source, a white blood cell scan was done, which showed increased localization within a left-sided upper mediastinum mass. Subsequently, chest CT scan with contrast showed an acute type B aortic dissection with mycotic aneurysm. Consequently, he was taken urgently for surgical management. He completed 6 weeks of penicillin G and was discharged to a rehabilitation center. This case illustrates both a rare entity, mycotic aneurysm secondary to Streptococcus pyogenes, and the importance of getting an Infectious Diseases consult in the setting of an unknown source of bacteremia.

Correlates of non-typhoidal Salmonella bacteraemia: A case-control study

OBJECTIVE

Limited up-to-date evidence exists on host-related characteristics of non-typhoidal Salmonella (NTS) bacteraemia in high-income countries. Correlates of NTS bacteraemia in Israel were examined in this study.

METHODS

A case-control study was conducted using the medical records of patients hospitalized with NTS bacteraemia in Jerusalem during 1997-2016 (n=106; 57 children, 49 adults). Two control groups were included: (1) randomly selected controls (n=101), who were patients hospitalized due to bacteraemia with other pathogens; (2) patients with salmonellosis without bacteraemia (n=112). Age-stratified logistic regression models were constructed.

RESULTS

In children, a recent emergency room visit was associated with an increased likelihood of NTS bacteraemia. In adults, the likelihood of NTS bacteraemia versus salmonellosis increased in relation to Charlson comorbidity score (adjusted odds ratio (aOR) 1.29, 95% confidence interval (CI) 1.00-1.66, for each 1-point increase in the score), while an inverse association was found with haemoglobin level (aOR 0.72, 95% CI 0.54-0.95). Steroid therapy increased the likelihood of NTS bacteraemia compared to patients with bacteraemia due to other pathogens (aOR 5.22, 95% CI 1.01-26.93).

CONCLUSIONS

In children, NTS bacteraemia was probably present at their prior emergency room visit. A high comorbidity burden increased the likelihood of bacteraemia in adults with Salmonella infection, while haemoglobin level might be protective.

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.

Invasive Nontyphoidal Salmonella Disease in Africa

Nontyphoidal salmonellae (NTS) are a major cause of invasive (iNTS) disease in sub-Saharan Africa, manifesting as bacteremia and meningitis. Available epidemiological data indicate that iNTS disease is endemic in much of the region. Antimicrobial resistance is common and case fatality rates are high. There are well-characterized clinical associations with iNTS disease, including young age, HIV infection, malaria, malnutrition, anemia, and sickle cell disease. However, the clinical presentation of iNTS disease is often with fever alone, so clinical diagnosis is impossible without blood culture confirmation. No vaccine is currently available, making this a priority area for global health research. Over the past ten years, it has emerged that iNTS disease in Africa is caused by distinct pathovars of Salmonella Typhimurium, belonging to sequence type ST313, and Salmonella Enteritidis. These are characterized by genome degradation and appear to be adapting to an invasive lifestyle. Investigation of rare patients with primary immunodeficiencies has suggested a key role for interferon gamma-mediated immunity in host defense against NTS. This concept has been supported by recent population-based host genetic studies in African children. In contrast, immunoepidemiological studies from Africa indicate an important role for antibody for protective immunity, supporting the development of antibody-inducing vaccines against iNTS disease. With candidate O-antigen-based vaccines due to enter clinical trials in the near future, research efforts should focus on understanding the relative contributions of antibody and cell-mediated immunity to protection against iNTS disease in humans.

An Uncommon Cause of Deep Vein Thrombosis: Mycotic Aneurysm Secondary to Salmonella Arteritis

Mycotic aneurysm is an uncommon surgical emergency with high mortality. Endovascular infection due to salmonella is the commonest cause of intra-abdominal mycotic aneurysm. We report a rare presentation of mycotic aneurysm in a 78-year-old man who presented to the accident and emergency department with deep vein thrombosis due to compression of the iliac vein by a mycotic aneurysm arising from the internal iliac artery and an adjacent abscess. A comprehensive review of the aetiology, clinical presentation and management of mycotic aneurysm secondary to salmonella arteritis is presented.

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.

Primary Infected Aortic Aneurysm: Clinical Presentation, Pathogen, and Outcome

PURPOSE

Infected aneurysm of the aorta and adjacent arteries is rarely occurring and can be fatal without surgical intervention. Within the medical community, the most efficacious treatment strategy to address infected aortic aneurysm remains controversial. In this study, we have reviewed our treatment experience with 109 patients.

METHODS

We included in our study all consecutive patients treated for primary infected aortic aneurysm at our facility between 1995 and 2011. Aneurysm-related mortality was defined as the presence of in-hospital and late mortality related to infection or postoperative complications.

RESULTS

The median patient age was 72 years (range, 35-88), and 87 (80%) were male. Pathogen was isolated in 101 patients, and the most common microorganism identified was non-typhoid Salmonella in 61 (60%), followed by Staphylococcus aureus in 16 (16%) and Streptococci species in 7 (7%). Eighty-five (78%) patients underwent surgical treatment. Surgery included open repair with in-situ graft replacement in 77 (71%) and endovascular repair in 8 (7%). The aneurysm-related mortality rate was 67% in medically treated and 21% in surgically treated patients, with a median follow-up duration of 31.5 months (range 1-189). Additionally, risk factors for aneurysm-related mortality included old age, chronic lung disease, psoas muscle abscess, short duration of preoperative antibiotics, no operation, and probably endovascular repair.

CONCLUSIONS

Non-typhoid Salmonella was the most common pathogen found in our study group patients with infected aortic aneurysm. It appears that prolonged preoperative antibiotic treatment followed by open in-situ graft replacement remains the preferred and most effective treatment strategy.

KEY WORDS

Infected aortic aneurysm; Outcome; Pathogen; Surgery.

Invasive Salmonellosis in Humans

Human salmonellosis is generally associated with Salmonella enterica from subspecies enterica (subspecies I). Acute infections can present in one of four ways: enteric fever, gastroenteritis, bacteremia, or extraintestinal focal infection. As with other infectious diseases, the course and outcome of the infection depend on a variety of factors, including the infecting organism, the inoculating dose, and the immune status and genetic background of the host. For serovarsTyphi and Paratyphi A there is a clear association between the genetic background of the serovar and systemic infection in humans. For serovars Paratyphi B and Paratyphi C, a good clinical description of the host and detailed population genetics of the pathogen are necessary before more detailed genetic studies of novel virulence factors,or host factors,can be initiated. For the nontyphoidalserovars (NTS) the situation is less clear. Serovars Typhimurium and Enteritidis are the most common within the food chain, and so the large number of invasive infections associated with these serovars is most likely due to exposure rather than to increased virulence of the pathogen. In Africa, however, a closely related group of strains of serovar Typhimurium, associated with HIV infection, may have become host adapted tohumans, suggesting that not all isolates called "Typhimurium" should be considered as a single group. Here we review current knowledge of the salmonellae for which invasive disease in humans is an important aspect of their population biology.

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 cardiac salmonellosis: two case reports and a review of the literature

Nontyphoidal Salmonella, especially Salmonella enterica, is a rare cause of endocarditis and pericarditis that carries a high mortality rate. Proposed predisposing conditions include immunodeficiency states, congenital heart defects, and cardiac valve diseases. We present 2 cases of cardiovascular salmonellosis. The first case is that of a 73-year-old woman with mechanical mitral and bioprosthetic aortic valves who died from sequelae of nontyphoidal Salmonella mitral valve vegetation, aortic valve abscess, and sepsis. The second case is that of a 62-year-old man with a recent systemic lupus erythematosus exacerbation treated with oral steroids, who presented with obstructive features of tamponade and sepsis secondary to a large S. enteritidis purulent pericardial cyst. He recovered after emergent pericardial drainage and antibiotic therapy. Identifying patients at risk of cardiovascular salmonellosis is important for early diagnosis and treatment to minimize sequelae and death. We reviewed the literature to identify the predisposing risk factors of nontyphoidal Salmonella cardiac infection.

A retrospective study of secondary bacteraemia in hospitalised adults with community acquired non-typhoidal Salmonella gastroenteritis

Background

The clinical significance of bacteraemia secondary to non-typhoidal Salmonella (NTS) gastroenteritis in hospitalised adults is uncertain.

Methods

Adults admitted to a hospital in Liverpool, UK, with NTS gastroenteritis were identified using hospital discharge data and laboratory records. Patients with known HIV infection were excluded. Risk factors for a complicated or fatal course were determined.

Results

Between 1982 and 2006 inclusive, 633 adults were identified. Serovars causing infection included Enteritidis (46.6%), Typhimurium (27.6%) and Virchow (4.9%). A blood culture was taken in 364 (57.5%) patients who were generally sicker than those who were not cultured. Bacteraemia was detected in 63 (17.3%) patients who had blood cultures taken (63/633 (10.0%) of all patients). Bacteraemia was more common in those aged ≥ 65 years (p < 0.001) and in those aged < 65 years who had an underlying chronic disease. A complicated course occurred in 91 (25.0%) patients who had had a blood culture taken (148/633 (23.4%) of all patients). Independent factors associated with a complicated or fatal course among the patients investigated with a blood culture were bacteraemia (Adjusted Odds Ratio 5.34, 95% CI 2.86–9.95); new onset confusion or coma (AOR 4.80, 95% CI 1.91–12.07); prolonged symptoms prior to admission (AOR 2.48, 95% CI 1.44–4.27); dehydration (AOR1.90, 95% CI 1.07–3.38); and absence of fever (AOR 0.56, 95% CI 0.32–0.95). The 30 day attributable case fatality for all patients was 1.5%.

Conclusions

In this study secondary bacteraemia, as well as other clinical factors, was independently associated with a complicated or fatal course in non-HIV infected adults admitted to hospital with NTS gastroenteritis.

Salmonella aortitis treated with endovascular aortic repair: a case report

INTRODUCTION

Salmonella is a typical cause of aortitis, which is associated with high morbidity and mortality. In infrarenal disease, besides open surgery, endovascular aortic repair as an alternative treatment has been reported. To the best of our knowledge, we report the first successful endovascular aortic repair documented by necropsy to date.

CASE PRESENTATION

A 67-year-old Caucasian man presented with low back pain, fever and positive blood cultures for Salmonella Enteritidis. A computed tomography scan showed an enlargement and intramural hematoma of the infrarenal aortic wall; a Salmonella aortitis was suspected and antimicrobial therapy initiated. Because of substantial comorbidities, endovascular aortic repair was favored over open surgery; postoperatively the antibiotic treatment was continued for 12 months. Post-mortem there were neither macroscopic nor microscopic signs of aortitis or graft infection.

CONCLUSIONS

We could demonstrate by necropsy that endovascular aortic repair of infrarenal aortitis with prolonged pre- and postinterventional antibiotic therapy for 12 months was a minimally invasive alternative and should be considered in selected clinically stable patients with substantial co-morbidities.

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.

Clinical and economic evaluation of BBL CHROMagar Salmonella (CHROMSal) versus subculture after selenite broth enrichment to CHROMSal and Hektoen enteric agars to detect enteric Salmonella in a large regional microbiology laboratory

Stool culture for enteric pathogens is one of the most labor-intensive clinical microbiology procedures. Direct plating of stool to BBL CHROMagar Salmonella (CHROMSal) (BD Diagnostics, Sparks, MD) versus subculture after selenite broth enrichment (Sel) to CHROMSal (Sel-CHROMSal) and Hektoen enteric agar (Sel-Hek) (PML Microbiologicals, Eugene, OR) to detect Salmonella were compared. The number of colony picks and biochemical/serotyping tests per plate was recorded. A cost comparison was done. Fifty-one of 2999 (1.7%) stools yielded Salmonella sp., and 80% of isolates grew on CHROMSal by 24 h. CHROMSal demonstrated much less false-positive growth compared to Sel-Hek (P < 0.0001), which reduced biochemical and serotyping tests by 85% and 20%, respectively. Sel-CHROMSal and CHROMSal versus Sel-Hek improved enteric Salmonella detection when compared to a true positive "gold standard" (i.e., recovery by any culture method) with a sensitivity, specificity, positive predictive value, and negative predictive value of 100% and 94.12%, 100% and 99.97%, 100% and 97.96%, and 100% and 99.90%, respectively. CHROMSal use would result in substantial cost and labor savings.

Prognostic factors and clinical features of non-typhoid Salmonella bacteremia in adults

BACKGROUND

Infections caused by non-typhoid Salmonella (NTS) have increased, and the increasing incidence of multidrug-resistant NTS bacteremia in adult patients has also been noted. This study aimed to investigate the clinical and microbiological characteristics of NTS bacteremia.

METHODS

A total of 71 episodes of NTS bacteremia among 65 patients were identified between 2004 and 2006. Clinical characteristics were collected from medical records. The agar dilution method described by the Clinical and Laboratory Standards Institute was used to determine the in vitro activities of each antibiotic. Multiple logistic regression analysis was used to evaluate the relationship between patient characteristics and all other covariates studied for prognosis.

RESULTS

Salmonella enteritidis was isolated in 30 cases (42.3%), Salmonella typhimurium in 22 (31.0%), and Salmonella choleraesuis in 19 (26.7%). Thirty-two (45.1%) isolates of 71 NTS bacteremias were susceptible to chloramphenicol, 37 (52.1%) to ampicillin, 47 (66.2%) to trimethoprim/sulfamethoxazole (TMP/SMX), 56 (78.9%) to moxifloxacin, 57 (80.3%) to ciprofloxacin and levofloxacin, and 71 (100%) to ceftriaxone. The crude 30-day mortality rate was 19.7%. In multiple logistic regression analysis, the following variables were independent and significant predictors of mortality: coma (odds ratio, 12.03) and inadequate antibiotic treatment (odds ratio, 6.63).

CONCLUSION

S. enteritidis was the most frequently isolated serotype. High resistance rates of NTS to some readily available antimicrobials (ampicillin, chloramphenicol, TMP/SMX, fluoroquinolones) were found. Patients with the factor of coma or inadequate antibiotic treatment had poor prognosis.

Non-typhoidal Salmonella septic arthritis in an immunocompetent child with a pharyngeal streptococcal infection

We report the case of an immunocompetent child who showed monoarticular arthritis and fever, preceded by pharyngitis and arthralgias. Because group A beta-hemolytic Streptococcus had been detected in the pharyngeal swab, erythromycin was given on admission. However, based on ultrasound examination, therapy with ceftriaxone and joint fluid drainage were promptly performed, and a rapid and full recovery followed. Meanwhile, Salmonella enterica infection was revealed in blood and joint fluid. Our case suggests that septic arthritis caused by a non-typhoidal Salmonella infection may occur without gastrointestinal manifestations and concomitantly with a pharyngeal streptococcal infection.

Long-term outcome and short-term survival of patients with systemic lupus erythematosus after bacteraemia episodes: 6-yr follow-up

OBJECTIVE

To describe the nature of bacteraemia in SLE patients and determine the short-term survival and long-term outcome of these patients.

METHODS

Analysis of the medical records of 1442 SLE patients who were regularly followed up in a tertiary teaching medical centre from 2000 to 2005.

RESULTS

Among 1442 SLE patients, 240 patients (17%) developed at least one episode of bacteraemia, corresponding to an incidence of 92.7 cases/1000 hospital admissions. Since SLE diagnosis, the overall survival of our patients was 92% at 5 yrs, 86% at 10 yrs and 79% at 15 yrs. However, after one episode of bacteraemia, the survival decreased to 76% at 30 days and 67% at 360 days. Of the 336 episodes of bacteraemia, 167 were community-acquired (49.7%) and 169 were nosocomial (50.3%). Staphylococcus aureus was the leading cause of Gram-positive bacteraemia. Among Gram-negative bacteria, non-typhoidal Salmonella and Escherichia coli were the most common species. Community-acquired Salmonella and Streptococcus bacteraemia were more common than nosocomial infections. Klebsiella and Acinetobacter spp. were significantly more responsible for nosocomial than community-acquired bacteraemia. Patients infected with Acinetobacter, Klebsiella or Pseudomonas had lower probabilities of 14-day survival (71.4, 55.6, 42.9%, respectively).

CONCLUSIONS

Among SLE patients, an episode of bacteraemia was associated with an unfavourable long-term outcome. The bacterial species significantly influenced short-term survival. Therefore, when empiric antibiotic therapy is initiated in SLE patients who are suspected of bacteraemia, we suggest use of antibiotics that are effective against Pseudomonas, Klebsiella, Acinetobacter, S. aureus, and E. coli.

Bacteraemia due to non-typhoidal Salmonella in Thailand: clinical and microbiological analysis

The prevalence of non-typhoidal Salmonella (NTS) bacteraemia has risen in many countries and is probably related to the increase in HIV infection. There is little information regarding NTS bacteraemia in Thailand, where the HIV infection rate increased 13.6-fold during the period 1992-2004. This study aimed at surveying the prevalence as well as analysing the clinical and microbiological features of NTS bacteraemia at a large university hospital in Thailand. Patients with positive blood cultures for NTS during 2005 were retrospectively reviewed for their demographics, underlying diseases and microbiological profiles. A total of 135 patients had NTS bacteraemia. Salmonella group C was predominant. The most common underlying disease was HIV infection. Up to 30% of NTS isolates were identified as multidrug resistant. This study should prompt an alert regarding the evolving pattern of NTS bacteraemia in Thailand.

Surgical Pathology of Infected Aortic Aneurysm and Its Clinical Correlation

Pathology of infected aortic aneurysm and its clinical correlation have rarely been reported. Between 1995 and 2005, 48 patients with infected aortic aneurysm underwent in situ graft replacement. Twenty-five patients had a suprarenal and 23 patients had an infrarenal infection. The most common responsible pathogen was nontyphoid Salmonella in 32 patients (67%). During operation, gross pus was present in 26 patients (54%). On pathological examination, aortic atherosclerosis was present in all cases, acute suppurative inflammation was present in 31 patients (65%), and bacterial clumps were present in five patients (10%). Positive culture of the aneurysm wall was present in 14 patients (29%). There were 10 patients with prosthetic graft infection (21%) and 12 patients with aneurysm-related death (25%). Although statistically insignificant, local purulent infection with positive culture of the aneurysm wall, gross pus during operation, or acute suppurative inflammation on pathology tended to be associated with high risk of prosthetic graft infection and aneurysm-related death. In conclusion, infected aortic aneurysm occurred in patients with aortic atherosclerosis. On pathology, acute suppurative inflammation was present in the majority of cases but bacterial clumps were not commonly present. Local purulent infection tended to be associated with high risk of prosthetic graft infection and aneurysm-related death.

Salmonella ovarian abscess following travel diarrhoea episode

The case of a 36-year-old woman with a non-typhoidal Salmonella ovarian abscess is reported. Remarkably, pathological findings of the oophorectomy piece did not demonstrate any pre-existing ovarian abnormalities.

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

BACKGROUND

Nontyphoid Salmonella (NTS) isolates lead to not only self-limited, acute gastrointestinal infections, but also bacteraemia with or without extraintestinal focal infections (EFIs). The risk factors associated with EFIs in adults with NTS bacteraemia were not clearly elucidated.

METHODS

In a medical center in southern Taiwan, patients aged > or = 18 years with NTS bacteraemia between January 1999 and June 2005 were included for analysis.

RESULTS

Of 129 patients, 51 (39.5%) were complicated with EFIs. The most common EFI was mycotic aneurysm, followed by pleuropulmonary infections and spinal osteomyelitis. Compared to patients with primary bacteraemia, those with EFIs had higher leucocyte counts (P = 0.004) and higher serum levels of C-reactive protein (P < 0.0001). The development of EFIs was associated with a higher mortality, more severe septic manifestations, longer hospital stays and duration of antimicrobial therapy. Univariate analysis revealed that diabetes mellitus (P = 0.02), hypertension (P = 0.02) and chronic lung disease (P = 0.006) were significantly associated with EFIs. However, patients with malignancy (P = 0.01) and immunosuppressive therapy (P = 0.03) were less likely to develop EFIs. On the basis of multivariate analysis, an independent factor for the occurrence of EFIs was age [adjusted odds ratio (aOR) 1.05; 95% confidence interval (CI) 1.02-1.07; P < 0.0001], whilst malignancy was negatively associated with EFIs (aOR 0.16; 95% CI 0.14-0.78; P = 0.01).

CONCLUSION

Amongst patients with NTS bacteraemia, EFIs often occurred in the aged, and were associated with a higher mortality and morbidity. Recognition of specific host factors is essential for identification of EFIs which often demand early surgical interventions and prolonged antimicrobial therapy.

High incidence of intravascular focus in nontyphoid Salmonella bacteremia in the age group above 50 years: a population-based study

Questions regarding the relative frequency of vascular complications in nontyphoid Salmonella bacteremia are pending, and the true population-based age-related incidence is not known. We reviewed all cases of nontyphoid Salmonella bacteremia during a 10-year period from 1994 through 2003 in a well-defined population of 492,843 residents in North Jutland County, Denmark. 77 of a total of 111 cases occurred in patients >50 years old. In this age group, five cases of mycotic aneurysm and two cases of endocarditis were documented, corresponding to a 9% occurrence. The annual incidence rate of endovascular nontyphoid Salmonella infection in this age group was 4.4 per 1,000,000 person years. The mortality was 43% in cases with endovascular infection, and surgical procedures were important for survival. We conclude that in patients older than 50 years, detection of nontyphoid Salmonella bloodstream infection should be followed by examinations for mycotic aneurysms and endocarditis.

Antimicrobial drug resistance in salmonella-infected aortic aneurysms

BACKGROUND

Salmonella infection of the aorta and adjacent arteries is rare, but life-threatening. There is an increasing number of infections caused by antimicrobial drug resistant Salmonella. This study sought to assess the association between antimicrobial drug resistance and clinical outcomes of patients with Salmonella-infected aortic aneurysm.

METHODS

Data were collected by retrospective chart review. Between October 1995 and October 2004, 34 patients with Salmonella-infected aortic aneurysm were included. Aneurysm-related deaths were defined as hospital deaths and late deaths due to prosthetic graft infection. Analysis was performed using the chi2 test, Fisher's exact test, and Mann-Whitney test.

RESULTS

Nineteen patients had a suprarenal and 15 patients had an infrarenal aortic infection. The most common responsible pathogen was group C Salmonella (47%). Ciprofloxacin-resistant Salmonella infection occurred since March 2001 and the rate increased from 0 per 15 in the years before March 2001 to 5 per 19 in the years after March 2001 (p = 0.005 by Fisher's exact test). Among the 26 patients who had combined medical and surgical therapy, 4 died in the hospital and 4 died of late prosthetic graft infection 3 to 6 months after operation, whereas 4 of the 8 who had medical therapy alone died of aneurysm rupture during hospitalization. The actuarial survival rates by the Kaplan-Meier method were 64% at 6 months, 61% at 1 year, and 56% at 5 years. The risk factors for aneurysm-related death were old age (78.5 +/- 9.7 years vs 63.5 +/- 11.4 years; p < 0.001) and ciprofloxacin-resistant Salmonella infection (4 of 5 vs 8 of 29; p = 0.042).

CONCLUSIONS

There was an increased mortality associated with ciprofloxacin resistance in infected aortic aneurysms with Salmonella. With an increasing incidence of ciprofloxacin resistant Salmonella, third generation cephalosporin is the antibiotic of choice for Salmonella-infected aneurysm.

[Thoracic infectious aortitis: microbiology, pathophysiology and treatment]

BACKGROUND

Thoracic infectious aortitis are currently rare. They are always lethal without any treatment. The microorganisms involved are numerous with particular pathophysiological characteristics for each bacterium. Treatment is difficult and must associate medical and surgical care.

RECENT FINDINGS

Bacterial epidemiology of infectious aortitis has been profoundly modified with the large use of antibiotics. Syphilitic aortitis were frequent in the beginning of the twentieth century but its incidence has dramatically fallen. It still exists and its clinical presentation must be known to begin an adequate treatment. Other bacterial aetiologies of these aortitis are more classical with high frequencies of Staphylococcus aureus and Streptococcus, which are often associated with infective endocarditis. Among Gram-negative bacteria, Salmonella spp are the most frequently met microorganisms. Atherosclerosis represents the principal risk factor of these infectious aortitis. It provokes arterial parietal damage useful for bacterial attach. A saccular aneurysm of infective origin can then appear. Treatment must consist on antibiotics before surgery; Tuberculous aortitis are also possible but are much more rare.

CONCLUSION

Thoracic infectious aortitis are very rare but must be known because of their poor prognosis. Treatment is difficult and prevention of atherosclerosis which is the most important risk factor of these diseases is therefore of greatest importance.

Salmonella enterica serotype Choleraesuis infections in pediatric patients

OBJECTIVE

Among >2500 nontyphoid Salmonella serotypes, Salmonella enterica serotype Choleraesuis shows a high predilection to cause systemic infections in humans. The objective of this study was to delineate the clinical and microbiologic features of pediatric patients with Salmonella Choleraesuis infections.

METHODS

Between May 1999 and February 2003, a total of 33 patients who were <18 years of age had culture-confirmed S Choleraesuis infections. Clinical features, laboratory values, treatment, outcome, and antimicrobial susceptibility patterns of the bacterial isolates were analyzed.

RESULTS

There were 24 males and 9 females with a mean age of 3 years. Fever (rectal temperature > or =38 degrees C; 94%) was the most common clinical presentation. Sixteen (52%) had fever lasting >5 days before admission. Only 18 (54%) patients had diarrhea. The most common mode of infection is occult bacteremia without focal infection. Compared with data obtained from adult patients, the gastrointestinal manifestations appeared more frequently seen in pediatric patients. However, among the 18 who presented with diarrhea, 14 had concomitant bloodstream infection. Only 1 patient, who was a case of acute leukemia, died of S Choleraesuis sepsis. Resistance to ceftriaxone, ciprofloxacin, ampicillin, trimethoprim-sulfamethoxazole, and chloramphenicol was found in 6%, 28%, 88%, 76%, and 83% of the isolates, respectively.

CONCLUSION

Children with S Choleraesuis infections usually presented with occult bacteremia with mild gastrointestinal involvement. The mortality of S Choleraesuis infections in previously healthy children is low. Ciprofloxacin resistance among S Choleraesuis isolates from pediatric patients was lower than that of isolates from adult patients. In view of the high rate of multidrug resistance, third-generation cephalosporins seem to be the drug of choice for treatment of invasive S Choleraesuis infections.

A Bayesian approach to acute infectious diarrhea in adults

Acute infectious diarrhea is a yearly occurrence for most Americans, and is associated with 1 million hospitalizations and about 6000 deaths in the United States annually. Up to 80% of acute infectious diarrhea is caused by noroviruses, which produce a clinically mild illness with a predictable short course and good outcome that make laboratory testing and antimicrobial treatment unnecessary. Most diarrhea-causing bacteria and protozoa can cause a clinical illness "like norovirus"; when they do so in healthy adults neither specialized testing nor antimicrobials is required. The presence or absence of epidemiologic evidence (such as travel, hospitalization, antibiotic use, other exposures)and clinical evidence (such as diarrhea frequency and duration, severity of abdominal pain and fever, character of stool, presence of chronic illness or immune deficiency) can change the probability of "not norovirus" from as low as 8% to as high as 100%. Such probabilities guide the use of laboratory testing and antimicrobial therapy in patients who have acute infectious diarrhea.

Bacteraemia due to ciprofloxacin-resistant Salmonella enterica serotype Choleraesuis in adult patients at a university hospital in Taiwan, 1996-2004

Eighty-one adult patients with Salmonella enterica serotype Choleraesuis (S. Choleraesuis) bacteraemia treated at a university hospital from 1996 to 2004 were evaluated. Multivariate analysis with a logistic regression model was used to characterize risk factors for primary bacteraemia and mycotic aneurysm and to determine the association of clinical characteristics of patients based on ciprofloxacin susceptibility of the causative organism. The incidence per 100,000 discharges was 0.76 in 1996 and 3.9 in 2004. The overall rate of ciprofloxacin resistance among these isolates was 59% (87 isolates) and the annual rate increased with time from 0% prior to 2000 to 80% in 2004. Among these patients, 48 (59%) had primary bacteraemia and 13 (16%) had secondary bacteraemia with mycotic aneurysm. Seventy (86%) patients had fever at presentation, 22 (27%) developed shock during hospitalization, and eight (10%) died of S. Choleraesuis bacteraemia. Patients with immunocompromised conditions had a higher risk of developing primary bacteraemia (OR 18.442, P < 0.001). Hypertension (OR 15.434, P = 0.002) and male gender (OR 7.422, P = 0.039) were associated with mycotic aneurysm. Patients with mycotic aneurysm were more frequently infected with ciprofloxacin-susceptible isolates (P = 0.028) and ciprofloxacin-susceptible isolates were also more frequently associated with recurrent infection than ciprofloxacin-resistant isolates (P = 0.038). The incidence of S. Choleraesuis bacteraemia has increased in the past 8 years, and this increase is associated with the upsurge of ciprofloxacin-resistant isolates.

Cutaneous leukocytoclastic vasculitis in a child with interleukin-12 receptor beta-1 deficiency

We report a patient with complete interleukin-12 receptor beta-1 deficiency associated with cutaneous leukocytoclastic vasculitis. The patient experienced Bacille Calmette Guérin, Mycobacterium chelonae, and Salmonella enteritidis infection. Vasculitis affecting both small arteries and postcapillary venules due to deposition of immune complexes was probably caused by S. enteritidis and/or M. chelonae infection.

Risk factors for nosocomial infective endocarditis in patients with methicillin-resistant Staphylococcus aureus bacteremia

BACKGROUND AND OBJECTIVE

Nosocomial infections caused by methicillin-resistant Staphylococcus aureus (MRSA) are increasing. Only a few studies of MRSA infective endocarditis have been conducted, and none have reported its risk factors. We sought to determine the host-related risk factors for infective endocarditis in patients with nosocomial MRSA bacteremia.

SETTING

A 2,000-bed, university-affiliated, tertiary-care hospital.

PATIENTS

Thirty-one patients with nosocomial MRSA infective endocarditis between October 1996 and May 2003.

DESIGN

A retrospective chart review was conducted. Data were compared with those from a control group of patients with nosocomial MRSA bacteremia. Logistic regression was used to identify independent risk factors for nosocomial infective endocarditis.

RESULTS

Compared with patients who had nosocomial MRSA bacteremia and no infective endocarditis, patients who had infective endocarditis had a higher incidence of chronic liver disease and a lower incidence of immunodeficiency. The risk of developing infective endocarditis was approximately 10% for patients with nosocomial MRSA bacteremia.

CONCLUSION

Patients with MRSA bacteremia and underlying chronic liver disease were prone to infective endocarditis.

Risk factors for bacteraemia and endovascular infection due to non-typhoid salmonella: a reappraisal

BACKGROUND

Endovascular infections are rare complications of non-typhoid salmonellosis. The diagnosis is frequently not established until the infection is advanced. It is important to identify high-risk patients and treat them as early as possible.

AIM

To identify risk factors for bacteraemia and endovascular infection in patients with non-typhoid salmonellosis.

DESIGN

Retrospective study.

SETTING

A single tertiary-care hospital in Taiwan.

METHODS

Data were collected by retrospective chart review. Log-logistic regression modelling was used to identify independent risk factors for bacteraemia and endovascular infection. We analysed the characteristics of patients with gastroenteritis vs. those with bacteraemia, and of bacteraemic patients with vs. without endovascular infection.

RESULTS

Between 1984 and 2004, there were 373 adult cases of non-typhoid salmonellosis. There were 76 intestinal Salmonella infections, 290 bloodstream infections (including 47 endovascular infections), and 7 extra-intestinal non-bacteraemic infections. The independent positive predictors of bacteraemia were systemic lupus erythematosus, liver cirrhosis, HIV infection, and solid organ cancers. The only independent positive predictor of endovascular infection was atherosclerosis. The independent negative predictors of endovascular infection were solid organ cancers and immunodeficiency.

DISCUSSION

Risk factors for atherosclerosis predisposed our patients with bacteraemia to endovascular infection. Although immunodeficiency predisposed patients to bacteraemia, it was associated with a low incidence of endovascular infection.