Mycotic aneurysms: uncommon pathogens and treatment conundrums

Introduction. Mycotic aneurysms, characterized by vessel wall dilation resulting from infections including bacteria, fungi, and viruses, are a rare but severe consequence of systemic infections. The term 'mycotic' was coined by William Osler to describe the first instance of a fungal-induced infected aneurysm. These aneurysms, accounting for 0.6% of aneurysms in Western countries, carry a higher risk of rupture compared to uninfected aneurysms. While the femoral artery, aorta, and intracranial arteries are commonly affected, pathogens causing mycotic aneurysms vary across regions. Diagnostic challenges arise from nonspecific symptoms such as fever, and discomfort. To prevent the substantial morbidity and mortality associated with mycotic aneurysms, timely identification and treatment are paramount. We present a case series highlighting mycotic aneurysms caused by some rare pathogens - Salmonella Paratyphi A, Streptococcus pneumoniae, and Pseudomonas aeruginosa. Methods. This case series involves three patients diagnosed with mycotic aneurysms due to unusual pathogens. We describe each patient's clinical presentation, medical history, physical examination findings, laboratory results, imaging studies, and the diagnostic process leading to the identification of the causative pathogens. Results. The first patient is a 70-year-old gentleman who presented with a ruptured infra-renal abdominal aortic pseudoaneurysm caused by Salmonella Paratyphi A. The second patient is a 66-year-old gentleman with a Streptococcus pneumoniae-associated descending thoracic aortic pseudoaneurysm. The third patient is a 70-year-old gentleman with a ruptured descending thoracic aortic aneurysm with an occult aorto-oesophageal fistula due to Pseudomonas aeruginosa infection. The description highlights unique clinical features, laboratory findings, imaging results, and the management approaches undertaken in each patient. Conclusion. Mycotic aneurysms, pose diagnostic challenges due to their nonspecific symptoms. Early identification and intervention are essential to mitigate the severe complications associated with these aneurysms. The presented cases underscore the need for a comprehensive approach to diagnosis and management, ensuring optimal outcomes for patients affected by mycotic aneurysms.

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.

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.

Acute Salmonella typhimurium Aneurysmal Aortitis With Bacteremia, Pneumonia, and Thoracic Aortic Dissection in an Elderly Male

Nontyphoidal Salmonellae (NTS) often cause self-limiting gastroenteritis in adults, known as salmonellosis. Salmonellosis has remained controlled in the United States due to intensive measures. Infrequently, these patients develop bacteremia and local or disseminated infections after salmonellosis. NTS endovascular infections are frequent in patients with immunosuppression, indwelling prosthetic vascular grafts, atherosclerotic vascular disease, or aortic aneurysms. NTS endovascular infections are uncommon in immunocompetent adults. Similarly, other focal extraintestinal infections such as pneumonia are also rare. A PubMed review of the medical literature reveals few cases in healthy adults with bacteremia, pneumonia, and acute infectious thoracic aortitis with dissection due to Salmonella typhimurium. We present an elderly White male with salmonellosis followed by S. typhimurium bacteremia with pneumonia and an acute thoracic aortic dissection three weeks later. He was treated successfully with endovascular repair and antibiotics.

Simple scoring algorithm to identify community-dwelling older adults with limited health literacy: a cross-sectional study in Taiwan

OBJECTIVE

Health literacy (HL) is the degree of individuals' capacity to access, understand, appraise and apply health information and services required to make appropriate health decisions. This study aimed to establish a predictive algorithm for identifying community-dwelling older adults with a high risk of limited HL.

DESIGN

A cross-sectional study.

SETTING

Four communities in northern, central and southern Taiwan.

PARTICIPANTS

A total of 648 older adults were included. Moreover, 85% of the core data set was used to generate the prediction model for the scoring algorithm, and 15% was used to test the fitness of the model.

PRIMARY AND SECONDARY OUTCOME MEASURES

Pearson's χ² test and multiple logistic regression were used to identify the significant factors associated with the HL level. An optimal cut-off point for the scoring algorithm was identified on the basis of the maximum sensitivity and specificity.

RESULTS

A total of 350 (54.6%) patients were classified as having limited HL. We identified 24 variables that could significantly differentiate between sufficient and limited HL. Eight factors that could significantly predict limited HL were identified as follows: a socioenvironmental determinant (ie, dominant spoken dialect), a health service use factor (ie, having family doctors), a health cost factor (ie, self-paid vaccination), a heath behaviour factor (ie, searching online health information), two health outcomes (ie, difficulty in performing activities of daily living and requiring assistance while visiting doctors), a participation factor (ie, attending health classes) and an empowerment factor (ie, self-management during illness). The scoring algorithm yielded an area under the curve of 0.71, and an optimal cut-off value of 5 represented moderate sensitivity (62.0%) and satisfactory specificity (76.2%).

CONCLUSION

This simple scoring algorithm can efficiently and effectively identify community-dwelling older adults with a high risk of limited HL.

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.

Evaluation of the clinical diagnostic value of traditional inflammatory markers and novel biomarkers in intracellular bacterial bloodstream infections

OBJECTIVES

The clinical symptoms of the patients with intracellular bacterial bloodstream infections (Intra-bac BSIs) are atypical, and no early and accurate diagnostic biomarkers exist, which can easily lead to misdiagnosis, inappropriate and delayed treatment. Therefore, it is imperative to find novel biomarkers to help clinical diagnosis of Intra-bac BSIs. The present study was initiated to evaluate the diagnostic values of traditional inflammatory biomarkers (PCT, WBC and NEU% in identifying the patients with Intra-bac BSIs, and to further explore into the possibility of using suPAR and sCD14-ST as novel biomarkers for Intra-bac BSIs.

METHODS

A multi-center retrospective study was conducted in three teaching hospitals in Chongqing. A total of 146 cases with BSIs, including 73 cases with Intra-bac BSIs and 73 cases with extracellular bacterial BSIs (Extra-bac BSIs) were enrolled in the retrospective study. We then prospectively enrolled 34 patients with Intra-bac BSIs, 34 patients with Extra-bac BSIs, 34 patients with viral infection and with normal medical examination results as a control group for further detection of sCD14-ST and suPAR by ELISA.

RESULTS

PCT levels, WBC counts and NEU% in patients with Intra-bac BSIs were not increased or minimally increased, they were significantly lower than that with Extra-bac BSIs (P < 0.05), especially those with the Brucella bacterial BSIs, demonstrated a respective negative rate of 84% and 92% for PCT and WBC counts. In the prospective study, the levels of suPAR and sCD14-ST in both the Intra-bac BSIs and the Extra-bac BSIs groups were significantly higher than those in the viral infection group and normal control group (P < 0.05). The areas under the curve (AUC) of Intra-bac BSIs were 0.830 for suPAR, and 0.855 for sCD14-ST. The sensitivity, specificity, Youden's index for suPAR and sCD14-ST were respectively 76.5%, 88.2%, 0.647 and 94.1%, 64.7%, 0.588.

CONCLUSIONS

Our multi-center study demonstrated that while the traditional inflammatory markers such as PCT, WBC counts, NEU% could not be served as promising diagnostic markers for Intra-bac BSIs; CRP can help guide the diagnosis of Intra-bac BSIs; Both suPAR and sCD14-ST could be considered as novel diagnostic biomarkers for Intra-bac BSIs as they showed good diagnostic accuracies in Intra-bac BSIs, especially suPAR.

Ceftiofur-resistant Salmonella enterica serovar Heidelberg of poultry origin - a risk profile using the Codex framework

Codex published the 'Guidelines for Risk Analysis of Foodborne Antimicrobial Resistance' to standardise the approach for evaluating risk posed by foodborne antimicrobial-resistant bacteria. One of the first steps in the guidelines is to compile a risk profile, which provides the current state of knowledge regarding a food safety issue, describes risk management options and recommends next steps. In Canada, ceftiofur/ceftriaxone-resistant Salmonella enterica subsp. enterica serovar Heidelberg from poultry was identified as an antimicrobial resistance (AMR) food safety issue. The first objective of this article was to contextualise this food safety issue, using the risk profile format of the Codex Guidelines. A second objective was to evaluate the applicability of the Codex Guidelines. This risk profile indicated that ceftiofur/ceftriaxone-resistant S. Heidelberg (CSH) was commonly isolated from poultry and was associated with severe disease in humans. Ceftiofur use in poultry hatcheries temporally mirrored the prevalence of CSH from poultry meat at retail and from people with salmonellosis. The evidence was sufficient to indicate the need for risk management options, such as restricting the use of ceftiofur in poultry. The Codex Guidelines provided a useful approach to summarise data for decision-makers to evaluate an AMR food safety issue.

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.

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.

Clinical characteristics in adult patients with Salmonella bacteremia and analysis of ciprofloxacin-nonsusceptible isolates

BACKGROUND/PURPOSE

The purpose of this study is to describe clinical characteristics of Salmonella bacteremia in adult patients and analyze ciprofloxacin-nonsusceptible isolates.

METHODS

A total of 101 Salmonella blood isolates from adult patients were collected from January 2011 to December 2013 in MacKay Memorial Hospital. Eight ciprofloxacin-nonsusceptible Salmonella blood isolates were screened for carbapenemase and other β lactamase genes. Isolates were examined by PCR for the quinolone resistance-determining region (QRDR) of all subunits for DNA gyrase (gyrA and gyrB) genes and topoisomerase IV (parC and parE) genes.

RESULTS

There were 22 (21.78%) S. enterica serovar B, 5 (4.95%) S. enterica serovar C1, 7 (6.93%) S. enterica serovar C2, 65 (64.36%) S. enterica serovar D, and 2 (1.98%) S. enterica serovar Typhi (S. typhi) isolates. β-lactamase gene screening and sequencing yielded only one blaCMY-2-positive isolate. In multivariate risk factor analysis, renal insufficiency [odds ratio (OR) 3.774; p = 0.020] and heart disease (OR 2.922; p = 0.027) were more common among elderly patients (≥65 years). Independent risk factors for ciprofloxacin-nonsusceptible strains included S. enterica serovar C2 (OR 28.430; p = 0.032), renal insufficiency (OR 13.927; p = 0.032), and immunosuppression agent usage (OR 60.082; p = 0.006). 87.50% (7/8) of isolates had gyrA mutation, 62.50% (5/8) had parC mutation, and none had gyrB and parE mutations. Isolates with both Ser83Phe/Asp87Asn gyrA and Thr57Ser/Ser80Ile parC mutation genes were highly ciprofloxacin-resistant (minimum inhibitory concentration ≥4 mg/L).

CONCLUSIONS

Elderly patients with renal insufficiency and heart disease were at risk for Salmonella bacteremia. Those for ciprofloxacin-nonsusceptible strains included S. enterica serovar C2, renal insufficiency, and immunosuppression agent usage. The 8 ciprofloxacin-nonsusceptible isolates carried gyrA and parC mutations, which cause resistance that poses a major concern.

Endovascular infection with Salmonella group C - a case report

INTRODUCTION

The risk of secondary endovascular infections after bacteremia with Salmonella spp. is augmented by preexisting atherosclerotic arterial lesions. Over the age of 50, the incidence varies between 25 and 35%.

CASE REPORT

A 57-year-old male, smoker, alcohol user, in poor social condition, was hospitalized for fever, malaise, left leg persistent thrombophlebitis, coxofemoral and back pain. His medical history was significant for recent sepsis with Salmonella group C, and a recent diagnosis of hepatitis C. During the antibiotic treatment, he complained of a left inguinal tumor, corresponding to a paravertebral image along the left psoas muscle identified by abdominal computed tomography. A paravertebral hematoma and an aneurysm of the left aortoiliac junction were repaired by surgery. The culture of the aneurysm was positive for Salmonella group C.

CONCLUSION

The differential diagnosis of lower limb persistent thrombophlebitis should consider the compression by abdominal aneurysm, consequent to a vascular complication from bacteremia with Salmonella spp.

Antimicrobial activity of ceftaroline and other anti-infective agents against microbial pathogens recovered from the surgical intensive care patient population: a prevalence analysis

BACKGROUND

Ceftaroline is a new parenteral cephalosporin agent with excellent activity against methicillin-sensitive (MSSA) and resistant strains of Staphylococcus aureus (MRSA). Critically ill surgical patients are susceptible to infection, often by multi-drug-resistant pathogens. The activity of ceftaroline against such pathogens has not been described.

METHODS

Three hundred thirty-five consecutive microbial isolates were collected from surgical wounds or abscesses, respiratory, urine, and blood cultures from patients in the surgical intensive care unit (SICU) of a major tertiary medical center. Using Clinical and Laboratory Standards Institute (CLSI) standard methodology and published breakpoints, all aerobic, facultative anaerobic isolates were tested against ceftaroline and selected comparative antimicrobial agents.

RESULTS

All staphylococcal isolates were susceptible to ceftaroline at a breakpoint of ≤1.0 mcg/mL. In addition, ceftaroline exhibited excellent activity against all streptococcal clinical isolates and non-ESBL-producing strains of Enterobacteriaceae (93.5%) recovered from SICU patients. Ceftaroline was inactive against ESBL-producing Enterobacteriaceae, Pseudomonas aeruginosa, vancomycin-resistant enterococci, and selective gram-negative anaerobic bacteria.

CONCLUSIONS

At present, ceftaroline is the only cephalosporin agent that is active against community and healthcare-associated MRSA. Further studies are needed to validate the benefit of this novel broad-spectrum anti-infective agent for the treatment of susceptible serious infections in the SICU patient population.

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.

Successful treatment of Salmonella aortitis with endovascular aortic repair and antibiotic therapy

We report a case of a 77-year-old Asian man with a history significant for type II diabetes mellitus and chronic kidney disease who presented with abdominal pain, nausea, vomiting and a 20-pound weight loss of 3 weeks' duration. Further evaluation revealed an infected mycotic aneurysm and distal abdominal aortitis as a result of Salmonella. This case demonstrates an interesting case of aortitis and a successful therapeutic approach.