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Medicina 2024Brain abscess is a focal suppurative process produced in most cases by bacterial agents. Aggregatibacter aphrophilus is a gram-negative bacteria belonging to the HACEK...
Brain abscess is a focal suppurative process produced in most cases by bacterial agents. Aggregatibacter aphrophilus is a gram-negative bacteria belonging to the HACEK group, which causes infective endocarditis, liver abscesses, among others. Brain abscesses secondary to this germ are rare and, in most cases, it is associated with contact with pets, poor dental hygiene or dental procedures. Treatment consists of drainage of the abscess (greater than 2.5 cm) combined with antibiotic therapy, ideally beta-lactams. The case of a 64-year-old male patient with no relevant history is here presented. He was admitted to the emergency service due to headache, hemianopsia of a week's duration and later tonic-clonic seizures, in whom imaging studies and culture of a brain lesion subsequently revealed a brain abscess due to A. aphrophilus. This case aims to illustrate about the rarity of this infection, because A. aphrophilus is a normal part of the oropharyngeal flora and respiratory tract, in which it rarely causes invasive bacteremia.
Topics: Brain Abscess; Humans; Male; Aggregatibacter aphrophilus; Middle Aged; Pasteurellaceae Infections; Anti-Bacterial Agents; Drainage
PubMed: 38683524
DOI: No ID Found -
Nature Communications Sep 2023Soluble HMW1C-like N-glycosyltransferases (NGTs) catalyze the glycosylation of Asn residues in proteins, a process fundamental for bacterial autoaggregation, adhesion...
Soluble HMW1C-like N-glycosyltransferases (NGTs) catalyze the glycosylation of Asn residues in proteins, a process fundamental for bacterial autoaggregation, adhesion and pathogenicity. However, our understanding of their molecular mechanisms is hindered by the lack of structures of enzymatic complexes. Here, we report structures of binary and ternary NGT complexes of Aggregatibacter aphrophilus NGT (AaNGT), revealing an essential dyad of basic/acidic residues located in the N-terminal all α-domain (AAD) that intimately recognizes the Thr residue within the conserved motif Asn-X-Ser/Thr. Poor substrates and inhibitors such as UDP-galactose and UDP-glucose mimetics adopt non-productive conformations, decreasing or impeding catalysis. QM/MM simulations rationalize these results, showing that AaNGT follows a S2 reaction mechanism in which the acceptor asparagine uses its imidic form for catalysis and the UDP-glucose phosphate group acts as a general base. These findings provide key insights into the mechanism of NGTs and will facilitate the design of structure-based inhibitors to treat diseases caused by non-typeable H. influenzae or other Gram-negative bacteria.
Topics: Glycosylation; Bacterial Proteins; Asparagine; Haemophilus influenzae; Glucose; Uridine Diphosphate
PubMed: 37723184
DOI: 10.1038/s41467-023-41238-1 -
Microbiology Spectrum Dec 2022Growing evidence suggests that oral infections can modify the course of systemic diseases. To date, epidemiological data on microbial oral infections are scarce. Here,...
Growing evidence suggests that oral infections can modify the course of systemic diseases. To date, epidemiological data on microbial oral infections are scarce. Here, we performed a comprehensive analysis of the trend and microbial diversity in oral infection specimens referred for clinical microbiology analysis from 2010 to 2020. The microbes were isolated by culture and were identified via matrix-assisted laser desorption ionization-time of flight mass spectrometry technology (MALDI-TOF MS) throughout the study period. A total of 1,014 referred samples from dental clinics in Stockholm County with dentoalveolar abscesses and jaw osteomyelitis being the main reason were identified. Overall, the microbial composition was dominated by (51%), followed by (19%), (12%), and (5%). At the genus level, Streptococcus spp. (36%), spp. (18%), and Staphylococcus spp. (11%) were among the most frequently reported. Interestingly, a strong increase in trend was noted for Streptococcus anginosus, Streptococcus mitis, Streptococcus sanguinis, Eikenella corrodens, spp., Aggregatibacter aphrophilus, Staphylococcus epidermidis, and Granulicatella adiacens during the study time ( = 0.66 to 0.89, < 0.05), and a minor increase was noted for Enterococcus faecalis and Klebsiella spp., whereas steady levels were noted for most of the others. The present study shows the diversity of bacteria that have been involved in dental infections during the last decade in the capital of Sweden, as well as the emerging oral microbiota trend, with clear clinical implications on the oral-systemic link. Oral diseases and associated microbes are a risk factor for systemic diseases and can change the courses of these diseases. To date, epidemiological data on microbial oral infections are scarce, and longitudinal reports are lacking. We present for the first time the microbial composition of severe oral bacterial infections determined via the MALDI-TOF mass spectrometry technique in a comprehensive study between 2010 and 2020 (11 years) in Stockholm County. The trend and microbial diversity of oral infections were analyzed on referred clinical microbiological samples and were processed by standardized protocols. Trend increase was noted for Streptococcus anginosus, Streptococcus mitis, Streptococcus sanguinis, Eikenella corrodens, spp., Aggregatibacter aphrophilus, Staphylococcus epidermidis, Granulicatella adiacens, Enterococcus faecalis, and Klebsiella spp. Our results provide new insights into the diversity and trend of oral microbiota that were involved in serious oral infections over the past decade in the capital of Sweden and may influence the oral-systemic link.
Topics: Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Bacteria; Carnobacteriaceae; Streptococcus; Streptococcus anginosus
PubMed: 36420577
DOI: 10.1128/spectrum.02487-22 -
Cureus Mar 2022, formerly known as , is one member of a group of bacteria referred to as HACEK (, , , , ) organisms. Infections from any of the HACEK organisms typically lead to very...
, formerly known as , is one member of a group of bacteria referred to as HACEK (, , , , ) organisms. Infections from any of the HACEK organisms typically lead to very poor outcomes and can be difficult to manage, especially when complicated by intracranial hemorrhage (ICH). HACEK organisms can also be difficult to grow on blood cultures, and is rarely seen, if at all. Traditionally, most laboratories follow an extended incubation protocol of 14 to 21 days to aid the growth of HACEK bacteria. Herein we report a case of infective endocarditis where resulted on blood culture in three days, in a patient with a right shoulder abscess, complicated by septic embolization leading to ICH. We explore a potential link between the prompt growth of on blood culture and the presence of the right shoulder abscess.
PubMed: 35464520
DOI: 10.7759/cureus.23107 -
European Heart Journal. Case Reports Feb 2021The prevalence of culture negative infective endocarditis (IEC) is reported as 2-7% though this figure may be as high as 70% in developing countries. This higher rate...
BACKGROUND
The prevalence of culture negative infective endocarditis (IEC) is reported as 2-7% though this figure may be as high as 70% in developing countries. This higher rate will, at least in part, be due to reduced diagnostic facilities though some data suggests higher rates even when appropriate cultures were taken. The frequency is significantly elevated in patients who have already been exposed to antibiotics prior to blood cultures. A rare cause of culture negative IEC is the HACEK group of organisms that are normal habitants of the oropharyngeal flora and account for 1-3% of native valve endocarditis. (A. aphrophilus) is a member of the HACEK group of organisms.
CASE SUMMARY
A 32-year-old gentleman with a previous bioprosthetic aortic valve presented with a 1-week history of diarrhoea, vomiting, malaise, and weight loss. He was awaiting redo surgery for stenosis of the bioprosthesis, which had been inserted aged 17 for aortic stenosis secondary to a bicuspid valve. The initial blood tests revealed liver and renal impairment with anaemia. A transoesophageal echocardiogram demonstrated a complex cavitating aortic root abscess, complicated by perforation into the right ventricle. He underwent emergency redo surgery requiring debridement of the aortic abscess, insertion of a mechanical aortic prosthesis (St Jude Medical, USA), annular reconstruction and graft replacement of the ascending aorta. Despite antibiotic therapy, he remained septic with negative blood and tissue cultures. Bacterial 16S rRNA gene sequencing confirmed infection, for which intravenous ceftriaxone was initiated. This was subsequently changed to ciprofloxacin due to neutropenia. The patient self-discharged from the hospital during the third week of antibiotic therapy. One week later, he was re-admitted with fever, night sweats, and dyspnoea. Transthoracic echocardiogram revealed a large recurrent aortic abscess cavity around the aortic annulus fistulating into the right heart chambers; this was confirmed by a computed tomography scan. There was dehiscence of the patch repair. Emergency redo aortic root replacement (25 mm mechanical valve conduit, ATS Medical, USA) and annular reconstruction was performed with venoarterial extracorporeal membrane oxygenation (VA-ECMO) support. VA-ECMO was weaned after 3 days. The patient completed a full course of intravenous meropenem and ciprofloxacin and made a good recovery.
DISCUSSION
IEC with oropharyngeal HACEK organisms is rare and difficult to diagnose, due to negative blood culture results. The broad-range polymerase chain reaction and gene sequencing with comparison to the DNA database is useful in these circumstances. This case demonstrates the importance of the 16S rRNA gene sequencing for HACEK infection diagnosis and appropriate antibiotic treatment.
PubMed: 33644660
DOI: 10.1093/ehjcr/ytab003 -
Blood Transfusion = Trasfusione Del... Sep 2021The aim of the study was to determine if periodontitis, which often causes transient bacteraemia, associates with viable bacteria in standard blood donations.
BACKGROUND
The aim of the study was to determine if periodontitis, which often causes transient bacteraemia, associates with viable bacteria in standard blood donations.
MATERIALS AND METHODS
This was a cross-sectional study of 60 self-reported medically healthy blood donors aged over 50 years. According to standard procedures, whole blood was separated by fractionation into plasma, buffy-coat, and red blood cell (RBC)-fractions. The buffy-coat was screened for bacterial contamination using BacT/ALERT. Samples from plasma and RBC-fractions were incubated anaerobically and aerobically at 37°C for 7 days on trypticase soy blood agar (TSA). For identification, colony polymerase chain reaction was performed using primers targeting 16S rDNA.
RESULTS
From 62% of the donors with periodontitis, bacterial growth was observed on at least 1 out of 4 plates inoculated with plasma or RBCs, whereas only 13% of plates inoculated with plasma or RBCs from periodontally healthy controls yielded bacterial growth (relative risk 6.4, 95% CI: 2.1; 19.5; p=0.0011). None of the donors tested positive for bacterial contamination using BacT/ALERT. Cutibacterium acnes was found in 31% of the donations from donors with periodontitis and in 10% of the donations from periodontally healthy donors. In addition, Staphylococcus species, Bacillus mycoides, Aggregatibacter aphrophilus, and Corynebacterium kroppenstedtii were detected.
DISCUSSION
Periodontitis increased the risk of bacterial contamination of blood products. Contaminating bacteria are often associated with the RBC-fraction. As the BacT/ALERT test is generally performed on platelet products, routine screening fails to detect many occurrences of viable bacteria in the RBC-fraction.
Topics: Aged; Bacteria; Blood Donors; Blood Platelets; Cross-Sectional Studies; Erythrocytes; Humans; Periodontitis
PubMed: 33539285
DOI: 10.2450/2021.0336-20 -
Oxford Medical Case Reports Jun 2021We present the case of a 25-year-old with a history of bicuspid aortic valve and ascending aortopathy who was successfully treated for infective endocarditis (IE) due to...
We present the case of a 25-year-old with a history of bicuspid aortic valve and ascending aortopathy who was successfully treated for infective endocarditis (IE) due to . His clinical course was complicated by a large aortic root abscess not initially visualised on transthoracic echocardiography or computerised tomography. The cardinal feature of progressive prolongation of the PR interval on serial electrocardiograms was the only sign associated with clinical deterioration and was the trigger for rapid investigation and urgent management. Our case emphasises the importance of simple bedside tests to identify dynamic clinical scenarios and the requirement for early further imaging in the management of IE.
PubMed: 34158957
DOI: 10.1093/omcr/omab043 -
BMC Infectious Diseases May 2022The bacterial genus Aggregatibacter was categorized in 2006 to accommodate the former Actinobacillus actinomycetemcomitans, Haemophilus aphrophilus, and H. segnis...
BACKGROUND
The bacterial genus Aggregatibacter was categorized in 2006 to accommodate the former Actinobacillus actinomycetemcomitans, Haemophilus aphrophilus, and H. segnis species. Aggregatibacter kilianii is a normal resident of the human upper respiratory tract but can also cause serious infections. A. kilianii is relatively newly identified and has been isolated from conjunctivitis, wounds, abdominal abscesses, and blood.
CASE PRESENTATION
An 80-year-old female patient with distal common bile duct cancer was admitted to our hospital with sudden loss of consciousness and general weakness, fever, and abdominal pain for 3 days. Two colonial morphologies were isolated from both the blood and bile cultures; one was identified as Streptococcus constellatus subsp. pharyngis, but the other was not recognized by Vitek2 and MALDI-TOF. The 16 S rRNA sequences showed 99.73% similarity with the sequence of A. kilianii strains.
CONCLUSION AND DISCUSSION
This article presents the first case of a clinical isolate of A. kilianii outside Europe. This case is also the first of the antimicrobial profile of this strain. This report highlights the importance of proper molecular identification for timely diagnosis and treatment of disease.
Topics: Aged, 80 and over; Aggregatibacter; Aggregatibacter aphrophilus; Female; Humans; Streptococcus
PubMed: 35619055
DOI: 10.1186/s12879-022-07471-7 -
Infection and Drug Resistance 2024The HACEK group comprises spp., , , , and , are Gram-negative bacteria that are slow-growing and fastidious. These organisms are common causes of...
BACKGROUND
The HACEK group comprises spp., , , , and , are Gram-negative bacteria that are slow-growing and fastidious. These organisms are common causes of culture-negative endocarditis. However, brain abscesses caused by and have been rarely reported. The case we describe, which was promptly identified and successfully treated, will be meaningful for the diagnosis and treatment of such infectious diseases.
CASE PRESENTATION
Herein, we report a case of brain abscess in a young man who was infected with and . The patient was admitted to the hospital with sudden onset of vomiting, coma, and fever. Magnetic resonance imaging (MRI) of the brain and cerebrospinal fluid cell counts suggested cerebral abscess, he underwent drainage of the abscess and empirical antimicrobial therapy of meropenem (2 g every 8 hours) and linezolid (0.6 g every 12 hours) for more than 10 days without significant improvement. Metagenomic next-generation sequencing (mNGS) of drainage fluid and matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) detection for isolated bacteria from samples suggested the presence of and . After 7 weeks of ceftriaxone (2 g every 12 hours) and meropenem (2 g every 8 hours) intravenously, the patient was discharged with a normal temperature and brain MRI showed improvement of the lesion.
CONCLUSION
Similar cases reported in previous studies were always associated with bacterial blood dissemination after dental surgery or myocarditis; however, the patient in our case had no any associated risk factors. As far as we know, this is the only case of central nervous system infection caused by and that has utilized combined mNGS and MALDI-TOF MS in the diagnosis.
PubMed: 38628241
DOI: 10.2147/IDR.S458020 -
Scientific Reports Jan 2020Asymptomatic oropharyngeal carriage of Neisseria meningitidis peaks in adolescence and young adulthood. Following a meningococcal disease outbreak at a U.S. college, we...
Asymptomatic oropharyngeal carriage of Neisseria meningitidis peaks in adolescence and young adulthood. Following a meningococcal disease outbreak at a U.S. college, we profiled the oropharyngeal microbiomes of 158 students to identify associations between bacterial community composition and meningococcal carriage or risk factors for carriage, including male gender, smoking, and frequent social mixing. Metagenomic shotgun sequencing identified 268 bacterial taxa at the genus or species level, with Streptococcus, Veillonella, and Rothia species being most abundant. Microbiome composition showed weak associations with meningococcal carriage and risk factors for carriage. N. meningitidis abundance was positively correlated with that of Fusobacterium nucleatum, consistent with hypothesized propionic acid cross-feeding. Additional species had positive abundance correlations with N. meningitidis, including Aggregatibacter aphrophilus, Campylobacter rectus, Catonella morbi, Haemophilus haemolyticus, and Parvimonas micra. N. meningitidis abundance was negatively correlated with unidentified Veillonella species. Several of these species are commonly found in dental plaque, while N. meningitidis is primarily found in the pharynx, suggesting that ecological interactions extend throughout the oral cavity. Although risk factors for meningococcal carriage do not strongly impact most bacterial species in the oropharynx, variation in the upper respiratory tract microbiome may create conditions that are more or less favorable for N. meningitidis carriage.
Topics: Adolescent; Carrier State; Disease Outbreaks; Female; Humans; Male; Meningitis, Meningococcal; Microbial Interactions; Microbiota; Neisseria meningitidis; Oropharynx; Risk Factors; Sex Factors; Smoking; Social Behavior; Streptococcus; Students; Universities; Veillonella; Young Adult
PubMed: 31959912
DOI: 10.1038/s41598-020-57450-8