In Vitro and In Vivo Evaluation of 99mTc-Polymyxin B for Specific Targeting of Gram-Bacteria.

BACKGROUND: Infectious diseases are one of the main causes of morbidity and mortality worldwide. Nuclear molecular imaging would be of great help to non-invasively discriminate between septic and sterile inflammation through available radiopharmaceuticals, as none is currently available for clinical practice. Here, we describe the radiolabeling procedure and in vitro and in vivo studies of 99mTc-polymyxin B sulfate (PMB) as a new single photon emission imaging agent for the characterization of infections due to Gram-negative bacteria. RESULTS: Labeling efficiency was 97 ± 2% with an average molar activity of 29.5 ± 0.6 MBq/nmol. The product was highly stable in saline and serum up to 6 h. In vitro binding assay showed significant displaceable binding to Gram-negative bacteria but not to Gram-positive controls. In mice, 99mTc-HYNIC-PMB was mainly taken up by liver and kidneys. Targeting studies confirmed the specificity of 99mTc-HYNIC-PMB obtained in vitro, showing significantly higher T/B ratios for Gram-negative bacteria than Gram-positive controls. CONCLUSIONS: In vitro and in vivo results suggest that 99mTc-HYNIC-PMB has a potential for in vivo identification of Gram-negative bacteria in patients with infections of unknown etiology. However, further investigations are needed to deeply understand the mechanism of action and behavior of 99mTc-HYNIC-PMB in other animal models and in humans.

An unusual skin infection with Achromobacter xylosoxidans.

Achromobacter xylosoxidans is an emerging, multidrug-resistant pathogen capable of forming biofilms on medical products that primarily infects immunocompromised patients. We present the case of a 50-year-old immunocompetent woman who developed an A xylosoxidans granulomatous abscess at the attachment site of her insulin pump. She was successfully treated with surgical excision and oral trimethoprim-sulfamethoxazole (TMP-SMX). This case demonstrates further emergence of A xylosoxidans as a potential pathogen, not only in immunocompromised individuals but in any patient with an indwelling catheter.

Eikenella corrodens causing deep-seated infections. Six-year experience in a University Hospital in Madrid / Infecciones por Eikenella corrodens en localizaciones profundas. Experiencia de 6 años en un hospital universitario de Madrid

INTRODUCTION: Eikenella corrodens (EC) is part of the normal microbiota of the oropharynx and a recognised opportunistic pathogen. It is mainly involved in head and neck infections, but it has also been identified as a cause of pleuropulmonary and intraabdominal infections. Its identification could be difficult due to its fastidious growth requirements, especially in the context of polymicrobial infection and is probably underreported. METHODS: We carried out a retrospective 5-year review of clinical charts and laboratory database. RESULTS: We describe the clinical and microbiological characteristics of 9 deep-seated infections caused by EC, diagnosed in locations different from the head and neck. CONCLUSION: EC deep-seated infections are often found in patients with comorbid conditions and a history of interventional procedures. Due to the characteristic torpid evolution of EC abscesses, imaging to assess the necessity of debridement and avoid early cessation of antibiotics is necessary

INTRODUCCIÓN: Eikenella corrodens (EC) es parte de la microbiota habitual orofaríngea y un conocido patógeno oportunista. Está involucrado principalmente en infecciones de cabeza y cuello, pero también causa de infecciones pleuropulmonares e intraabdominales. Su identificación podría ser difícil debido a sus exigentes requisitos de crecimiento, especialmente en el contexto de la infección polimicrobiana y probablemente sea un microorganismo infradiagnosticado. MÉTODOS: Realizamos una revisión retrospectiva de 5 años de las historias clínicas y la base de datos del laboratorio. RESULTADOS: Describimos las características clínicas y microbiológicas de 9 casos de infecciones en localizaciones profundas causadas por EC, diagnosticadas en localizaciones diferentes de la cabeza y el cuello. CONCLUSIONES: Las infecciones profundas por EC aparecen con frecuencia en pacientes con comorbilidades y antecedentes de procedimientos invasivos. Dada la evolución tórpida característica de los abscesos causados por EC, emplear técnicas de imagen para valorar la necesidad de desbridamiento y evitar la retirada prematura de los antimicrobianos

Imaging findings of Stenotrophomonas maltophilia pneumonia: emphasis on CT findings between immunocompromised and immunocompetent patients.

BACKGROUND: Stenotrophomonas maltophilia (S. maltophilia) is a globally emerging, rare, waterborne, aerobic, gram-negative, multiple-drug-resistant organism, most commonly associated with respiratory tract infection in humans. Computed tomography (CT) findings in patients with S. maltophilia pneumonia are rarely reported. PURPOSE: To compare CT findings between immunocompromised and immunocompetent patients, and to determine characteristic imaging findings of S. maltophilia pneumonia. MATERIAL AND METHODS: CT findings of eight immunocompromised and 29 immunocompetent patients with proven S. maltophilia pneumonia were reviewed retrospectively. Different patterns of CT abnormalities between immunocompromised and immunocompetent patients were compared by Fisher's exact test. RESULTS: Patchy ground-glass opacities (GGOs) were the most common CT findings, present in 36 (97.3%) of the 37 patients. Among the patients with patchy GGOs, consolidation was seen in 29 (78.4%) patients, and centrilobular nodules were noted in 15 (40.5%) patients. The transaxial distribution of the parenchymal abnormalities was predominantly randomly distributed in 30 (81.1%) cases. Regarding longitudinal plane involvement, the predominant zonal distributions were the diffuse distribution (n=23, 62.2%) and the lower lung zone (n=14, 37.8%). None of the patients showed upper lung zone predominance. The proportion of patients with parenchymal CT findings or associated findings in the immunocompromised patients was not significantly different from that of the immunocompetent patients. However, lower lung zone predominance on the longitudinal plane was significantly more common in immunocompetent patients than in immunocompromised patients (14/29 vs. 0/8, P=0.015). And diffuse distribution of parenchymal abnormalities on a longitudinal plane was significantly more frequent in immunocompromised patients than in immunocompetent patients (8/8 vs. 15/29, P=0.015). CONCLUSION: The most common CT patterns of S. maltophilia pneumonia in immunocompromised and immunocompetent patients were patchy GGOs and consolidation. However, in immunocompetent patients, parenchymal abnormalities were more predominately distributed in lower lung zone than in immunocompromised patients; and in immunocompromised patients, parenchymal abnormalities were more diffusely distributed than in immunocompetent patients.

Pneumonia due to Pandoraea Apista after evacuation of traumatic intracranial hematomas:a case report and literature review.

BACKGROUND: Pandoraea species is a newly described genus, which is multidrug resistant and difficult to identify. Clinical isolates are mostly cultured from cystic fibrosis (CF) patients. CF is a rare disease in China, which makes Pandoraea a total stranger to Chinese physicians. Pandoraea genus is reported as an emerging pathogen in CF patients in most cases. However, there are few pieces of evidence that confirm Pandoraea can be more virulent in non-CF patients. The pathogenicity of Pandoraea genus is poorly understood, as well as its treatment. The incidence of Pandoraea induced infection in non-CF patients may be underestimated and it's important to identify and understand these organisms. CASE PRESENTATION: We report a 44-years-old man who suffered from pneumonia and died eventually. Before his condition deteriorated, a Gram-negative bacilli was cultured from his sputum and identified as Pandoraea Apista by matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS). CONCLUSION: Pandoraea spp. is an emerging opportunistic pathogen. The incidences of Pandoraea related infection in non-CF patients may be underestimated due to the difficulty of identification. All strains of Pandoraea show multi-drug resistance and highly variable susceptibility. To better treatment, species-level identification and antibiotic susceptibility test are necessary.

Severe purulent pericarditis caused by invasive Eikenella corrodens: case report and literature review.

BACKGROUND: Eikenella corrodens is a slowly growing gram-negative bacillus that can cause severe invasive disease in human. Although E. corrodens infections in various sites of human body have been well described, pericarditis caused by invasive E. corrodens has rarely been reported. CASE PRESENTATION: Here we report the case of a 63-year old male with a complaint of left shoulder pain. The patient was diagnosed as purulent pericarditis by chest computed tomography scan and ultrasound-guided pericardiocentesis, and the pathogen of E. corrodens was identified in the pericardial fluid culture. The clinical condition of the patient deteriorated quickly, and he died right after the drainage surgery even though the pathogen was sensitive to antibiotics treatment. CONCLUSION: E. corrodens is a rare pericarditis associated pathogen. Purulent pericarditis caused by E. corrodens presents atypical manifestations and rapid progression of infection in immunosuppressed individuals such as neutropenic patients. Earlier diagnosis and proper drainage surgery with effective antibiotics treatment may improve the prognosis.

Capnocytophaga canimorsus peritonitis diagnosed by mass spectrometry in a diabetic patient undergoing peritoneal dialysis: a case report.

BACKGROUND: Bacterial peritonitis is a serious complication of patients undergoing peritoneal dialysis (PD). Although the identification of causative organisms and use of appropriate antibiotics are essential for treatment, rare and fastidious bacteria are sometimes difficult to detect by conventional biochemical assays. Capnocytophaga canimorsus is a fastidious and slow-growing bacterium that forms a part of the normal oral flora of dogs and cats and is extremely rare as a peritonitis-causing organism. This report demonstrates the usefulness of a mass spectrometry-based technique in identifying such a rare organism in PD-related peritonitis and discusses the diagnosis and treatment of C. canimorsus peritonitis. CASE PRESENTATION: A 49-year-old woman with type 2 diabetes mellitus underwent PD for two years. Repeated exit-site infections led to subcutaneous pathway diversion two months ago. She was hospitalized with fever and abdominal pain as well as cloudy dialysis effluent. Laboratory data revealed increased serum C-reactive protein level and white blood cell (WBC) count in the effluent. Her exit site had no sign of infection, leading to the diagnosis of PD-related peritonitis. Initial therapy with intraperitoneal ceftazidime immediately ameliorated her symptoms, and the WBC count in the effluent normalized in five days. Culture test results of the dialysis effluent on admission were negative with no information regarding the infection route. However, mass spectrometry (MALDI Biotyper, Bruker Daltonics) successfully obtained the specific spectral pattern for C. canimorsus. She had four cats in her house and was advised not to allow the cats in the room where the bag exchange took place. CONCLUSIONS: C. canimorsus is a rare cause of peritonitis in PD patients and is usually susceptible to intraperitoneal third-generation cephalosporins. This mass spectrometry-based bacterial identification method could provide more opportunities to identify uncommon causes and promote appropriate antibiotics therapy in PD-related peritonitis.

Stenotrophomonas maltophilia brain abscesses after implantation of motor cortex stimulator.

We describe the first case of a patient with brain abscesses caused by Stenotrophomonas maltophilia as a complication after motor cortex stimulator implantation. Brain abscesses pose a challenge in diagnosis and treatment, because microbiological diagnosis is not always achieved, antibiotic drugs may not penetrate well into the CNS and some bacteria have resistances to typical empirical antibiotic drugs. In this case diagnosis was only made after removal of the stimulator and a long term treatment with antibiotic drugs was necessary. As neurostimulation devices become more common, formerly rare bacteria may become a more common complication. Bacteria with biofilm properties and a problematic resistance spectrum like Stenotrophomonas maltophilia should be included in the differential diagnosis, because they will not respond to the typical empirical treatment.

5-ALA Fluorescence in Case of Brain Abscess by Aggregatibacter Mimicking Glioblastoma.

BACKGROUND: At present, the differential diagnosis of magnetic resonance imaging enhancing lesions can still be challenging. Preoperative imaging is a valuable tool characterized by high informative value, even if false-positive and false-negative results are possible. In this context, 5-aminolevulenic acid (5-ALA) represents a significant adjunct in glioblastoma (GBM) surgery displaying an assumed specific accumulation only in tumor cells. However, it was anecdotally reported that in some cases it can also be detected in nonneoplastic lesions mimicking GBM, thus potentially leading to misdiagnosis. Moreover, precise identification of involved pathogens from intraoperative brain samples may remain difficult. We report the case of an abscess from Aggregatibacter mimicking a GBM both during preoperative imaging and intraoperatively, since showing 5-ALA fluorescence. CASE DESCRIPTION: A 54-year-old man presented with intense cephalalgia, vomiting, and scotomas in his left eye. Brain magnetic resonance imaging demonstrated a right temporo-occipital rim-enhancing mass, highly suggestive of a GBM, and for this reason the patient underwent 5-ALA-guided complete removal. Histopathologic analysis proved the lesion to be a bacterial abscess from Aggregatibacter as confirmed by polymerase chain reaction on bacterial deoxyribonucleic acid. CONCLUSIONS: 5-ALA fluorescence may not be specifically involved only in malignant tumor cells, thus raising the suspect for alternative diagnoses to GBM and inviting caution into fluorescence-guided surgery.

Thyroid abscess due to Eikenella corrodens in a pediatric patient.

Eikenella corrodens is one of the HACEK bacteria that is commensal microorganism of the oropharngeal flora. E. corrodens has been increasingly reported to cause pyogenic abscesses, especially in diabetic or immunocompromised adults. It is less frequently reported in immunocompotent children. Here, we report a deep neck infection, including the thyroid gland, in a previously healthy girl. E. corrodens was the only microorganism isolated in two different cultures. Antibiotic susceptibility is variable, in contrast to other oropharyngeal pathogens. Thus, to avoid delayed treatment, E. corrodens should always be considered in infections of the head and neck area.

Nasal septal abscess caused by anaerobic bacteria of oral flora.

Although nasal septal abscess (NSA) was formerly common, it has become rare since the development of antibiotics. NSA, if left untreated, can lead to intracranial complications such as meningitis and eventually result in saddle-nose deformity. NSA often occurs after injury, and indigenous skin bacteria such as Staphylococcus aureus are frequently detected. We treated a patient who had injured the upper alveolus in a fall on the stairs and developed NSA two weeks later. Anaerobic bacteria, including Veillonella parvula and Peptostreptococcus sp., were detected. Symptoms were relieved by needle and incisional drainage. Our patient represents a very rare case of NSA in terms of the cause of onset and the detected bacteria. Early drainage can result in good outcomes.

A 39-Year-Old Man With Diabetes, Pleuritic Chest Pain, and Multiple Cavitary Lung Nodules.

CASE PRESENTATION: A 39-year-old male presented to the ED with a 2-day history of fever (Temperature-Maximum 39°C), nonbloody productive cough, and worsening right-sided pleuritic chest pain. The patient denied shortness of breath, nausea, vomiting, sinus symptoms, and abdominal pain. His medical history included type 2 diabetes mellitus (glycated hemoglobin, 11.1), hyperlipidemia, and depression. He smoked marijuana but denied tobacco or illicit drug use. He reported no recent travels. He reported a 1-week history of left molar pain that began after he siphoned stagnant water with a straw from a refrigerator drip pan. He lived in Ohio all of his life. He denied any sick contacts. His medications include Lantus insulin at night, metformin, glimepiride, pravastatin, and Remeron.

Eikenella corrodens perirenal abscess resulting from a pancreatic fistula in a patient with chronic pancreatitis. Case report and literature review.

We present a case of a right perirenal Eikenella corrodens abscess in a patient with chronic pancreatitis and poor dental hygiene. Endoscopic Retrograde CholangioPancreaticography (ERCP) revealed a pancreatic fistula draining to the right perirenal loge. The patient was treated with broad-spectrum antibiotics, percutaneous drainage and endoscopic stenting of the duct of Wirsung, stopping the supply of the fistula. A full recovery in our patient was observed. Considering the uncommon location of the abscess, a review of the different aetiologies of perirenal abscesses and their distrubution patterns, and the endoscopic treatment of symptomatic pancreatic fistulas seemed worthwhile.

T2Bacteria magnetic resonance assay for the rapid detection of ESKAPEc pathogens directly in whole blood.

Objectives: To evaluate the magnetic resonance-based T2Bacteria Panel assay for direct detection of ESKAPEc (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Escherichia coli) pathogens in blood samples of patients with suspected bloodstream infection (BSI). Patients and methods: Adult patients admitted to the Emergency Medicine Department, Infectious Diseases Unit and ICU of a large tertiary-care hospital were included if they had a blood culture (BC) ordered concomitantly with a whole-blood sample for T2Bacteria testing. Results were compared with those of BC and other clinically relevant information. Results: A total of 140 samples from 129 BSI patients were studied. Single bacteria were detected in 15.7% (22/140) and 12.1% (17/140), and multiple bacteria in 2.9% (4/140) and 1.4% (2/140), of samples tested by T2Bacteria and BC, respectively. With respect to the six target (ESKAPEc) species, overall sensitivity and specificity of T2Bacteria across all detection channels in comparison with BC were 83.3% and 97.6%, respectively; these values increased to 89.5% and 98.4%, respectively, when a true-infection criterion (i.e. the same microorganism detected only by T2Bacteria was cultured from another sample type reflecting the source of infection) was used as the comparator. There were 808 T2Bacteria detection results across 112 samples, with concordant negative results, yielding a negative predictive value of 99.8%. The mean time to negative result was 6.1 ±âŸ1.5 h, whereas the mean time to detection/species identification was 5.5 ±âŸ1.4 h. Conclusions: The T2Bacteria Panel assay has the potential to provide accurate and timely diagnosis of ESKAPEc bacteraemia, which might support the direct therapeutic management of BSI patients.

Necrotizing Pneumonia Caused by Chromobacterium violaceum: Report of a Rare Human Pathogen Causing Disease in an Immunodeficient Child.

Chromobacterium violaceum is a rare, potentially serious pathogen. Most clinicians have no experience with its clinical appearance or treatment. We describe a case of a child presenting with necrotizing pneumonia caused by C. violaceum. We describe case complexities, including the need for a multidisciplinary approach to diagnosis and treatment.

Stereotactic Drainage of Brainstem Abscess With the BrainLab Varioguide™ System and the Airo™ Intraoperative CT Scanner: Technical Case Report.

BACKGROUND AND IMPORTANCE: Stereotactic biopsies or needle aspirations of posterior fossa lesions are technically challenging. Here we report a novel technique for performing these procedures employing the Airo™ intraoperative computed tomographic (CT) scanner and the VarioGuide™ articulated arm (BrainLab, Munich, Germany). CLINICAL PRESENTATION: A 62-yr-old woman presented with an irregularly shaped, enhancing lesion of the left pons/middle cerebellar peduncle. Slowed diffusion on magnetic resonance imaging suggested an abscess, but no definitive infectious agent/source could be identified. When the patient deteriorated despite broad-spectrum antibiotic therapy, she was taken to the operating room for stereotactic drainage of the abscess employing the described technique. A specific infectious agent (Eikenella corrodens) was identified from the aspirate, allowing for tailored antibiotic therapy. The procedure was well tolerated and the patient made a full recovery with minimal neurological sequelae. CONCLUSION: The combination of the Airo™ intraoperative CT and the Varioguide™ articulated arm allows for safe, accurate, and efficient targeting of posterior fossa lesions.