BACKGROUND: Moraxella osloensis rarely causes infection in humans, and most of the reported cases are not fatal. It is often difficult to identify M. osloensis using conventional biochemical methods.
METHODS: Here, we report a bacteremia case caused by M. osloensis in a patient with advanced lung cancer who initially presented symptoms of fever.
RESULTS: Blood culture revealed growth of a gram-negative bacterium, which was identified as M. osloensis through 16S rRNA gene sequencing and MALDI-TOF analyses. The patient could not recover from sepsis with empirical treatment.
CONCLUSIONS: As M. osloensis can cause serious infections in immunocompromised patients, its prompt identification is important.

Acute bacterial meningitis in infants and newborns represents a medical emergency and a significant cause of mortality and morbidity worldwide. Moraxella catarrhalis has been considered a microorganism with low pathogenic potential, and only in exceptional cases has it been found to cause meningitis in infants and immunocompetent people. We will now document an unusual case of an unexpected and sudden death of a 40-day-old infant due to acute meningitis from M. catarrhalis, apparently asymptomatic and subsequently diagnosed by an autopsy. According to our knowledge this is the first case of unexpected infant death due to undiagnosed M. catarrhalis meningitis.The suggested case, as well as for the rarity of such a fatal event, should be considered a caution to pediatrics and neonatologists for M. catarrhalis can cause paucisymptomatic meningoencephalitis in infants which can be potentially fatal.From a forensic point of view, an autopsy accompanied by a multidisciplinary assessment is always necessary in cases of unexpected infant deaths to identify the causes.

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BACKGROUND: Community acquired pneumonia (CAP), an acute infection of the pulmonary parenchyma acquired in the community, is generally treated in an outpatient setting and involves different etiological agents. In the adult community, the most common pathogen in the disease is Streptococcus pneumonia, though other multiple etiological agents (atypical) have been involved, including Mycoplasma pneumoniae, Chlamydophila pneumoniae, and Legionella pneumophila. The genus Moraxella consists of aerobic, oxidase-positive gram-negative coccobacilli. Moraxella catarrhalis is known to be a common inhabitant of the upper respiratory tract and has been implicated as an etiologic agent in multiple diseases of the respiratory tract (but not limited to), such as bronchitis, pneumonia, otitis media, and sinusitis. The species Moraxella osloensis is a gram-negative opportunistic human pathogen, which has been found to cause several human diseases and infections such as meningitis, vaginitis, sinusitis, bacteremia, endocarditis, and septic arthritis. However, due to the subject\'s rarity, there is a paucity of information in the medical literature regarding its clinical significance, epidemiological data and appropriate therapy. We present the first case reported in Israel of Moraxella osloensis bacteremia in a patient with multiple co-morbidities including C. difficile infection (CDI) carrier state which presented with clinical symptoms (supported by radiological features) of community-acquired pneumonia. The patient was initially treated with empiric antibiotics including a 3rd generation cephalosporin and a macrolide that were substituted with IV Augmentin (Amoxicillin-Clavulanic acid) according to the organism\'s sensitivity tests. Our patient showed remarkable clinical and laboratory improvement with the therapy mentioned above.

A-26-year-old man was admitted to our hospital with diffuse abdominal pain, nausea, and vomiting. He had a history of malignant nephrosclerosis, for which he had been receiving peritoneal dialysis (PD) for the past 14 months. His PD effluent was cloudy and turbid (white blood cell count, 10,528/μL; neutrophils 95.2%). A Gram-negative coccobacillus was isolated from peritoneal fluid culture. However, the organism could not be identified by matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) (Vitek MS, bioMérieux), but was identified as Moraxella osloensis by the 16S rRNA gene sequencing. He was successfully treated with intraperitoneal cefazolin therapy for 3 weeks without removing the intra-abdominal catheter. A literature review revealed three previous case reports all of which were diagnosed by MALDI Biotyper (Bruker Daltonics), suggesting that the identification of M. osloensis may vary depending on the type of MALDI-TOF MS system. In conclusion, we experienced a case of M. osloensis infection in a PD patient, which was successfully treated by antibiotic treatment, without removing the PD catheter.

BACKGROUND: Septic arthritis is a common rheumatologic condition with myriad microbiological causative agents. Moraxella is one of the very rare causes of septic arthritis. We hereby present the third case of Moraxella nonliquefaciens septic arthritis and the first case in a hematopoietic stem cell transplant patient (HSCT) along with a brief review of the literature.
METHODS: We used PubMed with google search engine to search the literature for reported cases of moraxella septic arthritis.
RESULTS: Information on 19 other cases of moraxella infectious arthritis was found. M. catarrhalis was the most common species isolated. Only 2 reports on M. nonliquefaciens were found; the first one in a multiple myeloma patient and the second one in a diabetic patient on hemodialysis. Predisposing conditions included inflammatory arthritis, prosthetic joints, diabetes, Human Immunodeficiency Virus (HIV) infection, Hepatitis C, hemodialysis, esophageal cancer, valve replacements, alcoholism and Intravenous (IV) drug use. The age group of the reported cases ranged from 3 months to 78 years.
CONCLUSIONS: Infectious arthritis with Moraxella spp. is a very rare entity which can occur in any age group and in the setting of various underlying medical conditions.

BACKGROUND: Respiratory syncytial virus is the most common cause of lower respiratory tract infections in infants and young children. While the majority of infants display only mild upper respiratory tract infection or occasionally otitis media, around one-third will develop an infection of the lower respiratory tract, usually bronchiolitis. There is now convincing evidence from a number of cohorts that respiratory syncytial virus is a significant, independent risk factor for later wheezing, at least within the first decade of life. The wide variation in response to respiratory syncytial virus infection suggests that susceptibility and disease are influenced by multiple host-intrinsic factors.
METHODS: A 2-year-old white girl presented to our Pediatric Allergy Clinic with recurrent crackles in addition to cough, fevers, and labored breathing since her first respiratory syncytial virus infection at the age of 7 months. She had been under the care of pulmonologists, who suspected childhood interstitial lung disease. She was hospitalized eight times due to exacerbation of symptoms and prescribed systemic and inhaled steroids, short-acting β2-mimetics, and antileukotriene. There was no short-term clinical improvement at that time between hospitalizations. During her hospital stay at the Pneumonology and Cystic Fibrosis Department in Rabka a bronchoscopy with bronchoalveolar lavage was performed. Laboratory bacteriological tests found high colony count of Moraxella catarrhalis (β-lactamase positive), sensitive to amoxicillin-clavulanate, in bronchial secretions and swabs from her nose. After this, infections were treated with antibiotics; she remained in good condition without symptoms. Crackles and wheezing recurred only during symptoms of infections. Therefore, we hypothesize that respiratory syncytial virus infection at an early age might cause severe damage of the lung epithelium and prolonged clinical symptoms, mainly crackles and wheezing, each time the child has a respiratory infection.
CONCLUSIONS: This case illustrates the importance of respiratory syncytial virus infection in an immunocompetent child. Pediatricians need to have a high index of suspicion and knowledge of recurrent symptoms associated with severe damage of the lung epithelium to establish the correct diagnosis.

Herein we report the case of a 10-year-old boy with an autosomal mosaic mutation who developed bacteremia. The causative agent was identified as Moraxella osloensis by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and 16S rRNA gene sequencing. In the pediatric population, there have been 13 case reports of infection attributed to M. osloensis and this is the fifth reported case of pediatric bacteremia due to M. osloensis. After Moraxella species infection was confirmed, the patient recovered with appropriate antimicrobial therapy. It is important to consider that M. osloensis can cause serious infections, such as bacteremia, in otherwise healthy children.

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BACKGROUND: Invasive diseases due to Moraxella catarrhalis are rare in children, even in immunocompromised hosts. Therefore, data regarding clinical characteristics and risk factors of such patients are limited. The aim of this study is to compare the clinical characteristics of patients with bacteremia due to Moraxella catarrhalis against those with bacteremia due to Streptococcus pneumoniae and Haemophilus influenzae.
METHODS: We performed a retrospective case-control study to compare patients younger than 18 years of age with positive blood cultures for the three pathogens between June 2008 and May 2014 at our institution. Data regarding patients\' demographics and clinical course were collected from their medical records. Three group comparisons, with M. catarrhalis as reference, were made by the Fisher\'s exact test and Wilcoxon rank sum test for discrete and continuous variables, respectively.
RESULTS: There were eight cases of M. catarrhalis, 110 cases of S. pneumoniae (105 patients) and 22 cases of H. influenzae. The M. catarrhalis group consisted of six females (75 %) with a mean age of 16 months. The majority of patients (7/8, 88 %) had underlying diseases; however, only one was immunocompromised. Characteristically, six patients (75 %) had medical devices including trans-nasal devices (5/8, 63 %). Univariate analysis revealed that underlying conditions (P = 0.005), trans-nasal devices (P < 0.001), and lower body weight (P = 0.016) and low white blood cell count (P = 0.011) at the onset of illness were associated with the M. catarrhalis group compared to the S. pneumoniae group. Meanwhile, the higher rates of the patients with underlying conditions and trans-nasal devices were associated with the M. catarrhalis group compared to the H. influenzae group (P = 0.039, P < 0.001, respectively).
CONCLUSIONS: The presence of underlying conditions, particularly in those with trans-nasal devices, were characteristic features of patients with bacteremia due to M. catarrhalis.