Aerococcus kribbianus sp. nov., a facultatively anaerobic bacterium isolated from pig faeces.

Two cocci-shaped, facultatively anaerobic, Gram-positive bacteria isolated from the faeces of a pig were designated as strains YH-aer221T and YH-aer222. Analysis of the 16S rRNA gene sequences revealed that the isolates were most closely related to Aerococcus suis JCM 18035T with 96.6 % similarity. The multi-locus sequence tree revealed that the isolates formed a sub-cluster adjacent to A. suis JCM 18035T. The average nucleotide identity values for the isolates and their most closely related strains were 71.8 and 71.7 %, respectively; and the digital DNA-DNA hybridization values for the isolates and their most closely related strains were 25.6 and 25.5 %, respectively. The main fatty acids were C18 : 1ω9c, C16 : 0 and C18 : 0. The cell wall contained the meso-diaminopimelic acid-based peptidoglycan. The two isolates shared the same metabolic pathways. Isolates YH-aer221T and YH-aer222 harboured the same CRISPR array with 33 and 46 spacers, respectively. Single-genome vs. metagenome analysis showed that the genomes of the isolates were not found in the available metagenome database. Given their chemotaxonomic, phenotypic and phylogenetic properties, YH-aer221T (= KCTC 25571T=JCM 35699T) and YH-aer222 (=KCTC 25573=JCM 35700) represent a novel taxon. The name Aerococcus kribbianus sp. nov. is proposed.

Carrier-based immobilization of Aerococcus viridansl-lactate oxidase.

l-Lactate oxidase has important applications in biosensing and finds increased use in biocatalysis. The enzyme has been characterized well, yet its immobilization has not been explored in depth. Here, we studied immobilization of Aerococcus viridansl-lactate oxidase on porous carriers of variable matrix material (polymethacrylate, polyurethane, agarose) and surface functional group (amine, Ni2+-loaded nitrilotriacetic acid (NiNTA), epoxide). Carrier activity (Ac) and immobilized enzyme effectiveness (ɳ) were evaluated in dependence of protein loading. Results show that efficient immobilization (Ac: up to 1450 U/g carrier; ɳ: up to 65%) requires a hydrophilic carrier (agarose) equipped with amine groups. The value of ɳ declines sharply as Ac increases, probably due to transition into diffusional regime. Untagged l-lactate oxidase binds to NiNTA carrier similarly as N-terminally His-tagged enzyme. Lixiviation studies reveal quasi-irreversible enzyme adsorption on NiNTA carrier while partial release of activity (≤ 25%) is shown from amine carrier. The desorbed enzyme exhibits the same specific activity as the original l-lactate oxidase. Collectively, our study identifies basic requirements of l-lactate oxidase immobilization on solid carrier and highlights the role of ionic interactions in enzyme-surface adsorption.

Aerococcus viridans Phage Lysin AVPL Had Lytic Activity against Streptococcus suis in a Mouse Bacteremia Model.

Streptococcus suis (S. suis) is a swine pathogen that can cause sepsis, meningitis, endocarditis, and other infectious diseases; it is also a zoonotic pathogen that has caused a global surge in fatal human infections. The widespread prevalence of multidrug-resistant S. suis strains and the decline in novel antibiotic candidates have necessitated the development of alternative antimicrobial agents. In this study, AVPL, the Aerococcus viridans (A. viridans) phage lysin, was found to exhibit efficient bactericidal activity and broad lytic activity against multiple serotypes of S. suis. A final concentration of 300 µg/mL AVPL reduced S. suis counts by 4-4.5 log10 within 1 h in vitro. Importantly, AVPL effectively inhibited 48 h S. suis biofilm formation and disrupted preformed biofilms. In a mouse model, 300 µg/mouse AVPL protected 100% of mice from infection following the administration of lethal doses of multidrug-resistant S. suis type 2 (SS2) strain SC19, reduced the bacterial load in different organs, and effectively alleviated inflammation and histopathological damage in infected mice. These data suggest that AVPL is a valuable candidate antimicrobial agent for treating S. suis infections.

Aerococcus agrisoli sp. nov., isolated from paddy soil.

A non-spore-forming, Gram-stain-positive, short rod-shaped strain, designated SJQ22T, was isolated from a paddy soil sample collected in Shanghai, PR China. A comparative analysis of 16S rRNA gene sequences showed that strain SJQ22T fell within the genus Aerococcus, forming a clear cluster with the type strains of Aerococcus viridans (98.6 % sequence similarity) and Aerococcus urinaeequi (98.5 % sequence similarity). Strain SJQ22T grew at 30-45 °C (optimum, 30 °C), pH 6.0-8.0 (optimum, pH 7.0) and with a NaCl concentration of 0-4 % (optimum, 1 %). Cells were negative for oxidase and catalase activity. Chemotaxonomic analysis showed that strain SJQ22T possessed C16:0 and C18:1 ω9c as the predominant fatty acids. The DNA G + C content was 39.0 mol%. Strain SJQ22T exhibited DNA-DNA relatedness levels of 13±2 % with A. viridans ATCC 11563T and 9±2 % with A. urinaeequi IFO 12173T. Based on the data obtained, strain SJQ22T represents a novel species of the genus Aerococcus, for which the name Aerococcus agrisoli sp. nov. is proposed. The type strain is SJQ22T (=JCM 33111T=CCTCC AB 2018283T).

Aerococcus viridans and Public Health: Oral Carriage and Antimicrobial Resistance in Stray Dogs and Cats in Algeria.

The current study aimed to determine the occurrence and antimicrobial resistance of oral Aerococcus viridans in stray dogs and cats in Algeria. Oral swabs from 200 stray animals (100 dogs and 100 cats) were collected and cultured on Columbia agar medium supplemented with 5% defibrinated sheep blood. Isolates were identified using analytical profile index Rapid 20 Strep commercial kits, and antibiotic susceptibility was determined using the disk diffusion method. Of the 200 animals sampled, 34 carried A. viridans in their oral cavities, with 26 isolates (76.47%) resistant to at least 2 drugs. Multidrug resistance profiles (to more than three different antimicrobials) were observed only in cats (26.08% of isolates). More isolates were resistant to erythromycin and tetracycline (71% and 65%, respectively) than to other antimicrobials. This is the first research study in Algeria detecting antimicrobial resistance in oral A. viridans isolated from dogs and cats and highlights potential public health concerns. Clinical trials registration number: 01/2018.

Aerococcus urinae urinary tract infection in a hospitalised patient: an increasingly common infection.

An elderly male with an extensive medical history was admitted for sepsis of unspecified origin; the source was later found to be an Aerococcus urinae urinary tract infection. Urinalysis and conventional urine culture were used in diagnosing this infection, and it was successfully treated with a 7-day course of intravenous ceftriaxone. The patient had no recurrence of urinary symptoms or development of complications at his follow-up. While A. urinae has traditionally been described as an uncommon and relatively avirulent source of urinary tract infections, increasing reports of positive isolation suggest its incidence may be higher than previously believed. Cases have been more frequently reported among elderly males with multimorbidity and repeat hospitalisation. A lower threshold of suspicion for A. urinae urinary tract infections in this population may better guide empiric therapy and help avoid potentially life-threatening complications.

Taxonomic considerations on Aerococcus urinae with proposal of subdivision into Aerococcus urinae, Aerococcus tenax sp. nov., Aerococcus mictus sp. nov., and Aerococcus loyolae sp. nov.

Average nucleotide identity analysis, based on whole genome sequences of 115 strains previously identified as Aerococcus urinae, an emerging uropathogen, discriminates at least six unique genomic taxa. The whole genome analysis affords clearer species boundaries over 16S rRNA gene sequencing and traditional phenotypic approaches for the identification and phylogenetic organization of Aerococcus species. The newly described species can be differentiated by matrix-assisted laser desorption ionization time-of-flight analysis of protein signatures. We propose the emendation of the description of A. urinae (type strain ATCC 51268T = CCUG 34223T=NCFB 2893) and the names of Aerococcus tenax sp. nov. (ATCC TSD-302T = DSM 115700T = CCUG 76531T=NR-58630T), Aerococcus mictus sp. nov. (ATCC TSD-301T = DSM 115699T = CCUG 76532T=NR-58629T), and Aerococcus loyolae sp. nov. (ATCC TSD-300T = DSM 115698T = CCUG 76533T=NR-58628T) for three of the newly identified genomic taxa.

Epidemiology and urological pathogenic potential of Aerococcus species in greater Glasgow and Clyde (Descriptive study of Aerococcus urinae in blood culture and urinary samples: clinical importance and potential marker of urinary tract pathology).

Introduction. Aerococcus species in particular A. urinae are increasingly reported as causative agents of bacteraemia, urinary tract infection, sepsis, and endocarditis. We sought to establish the epidemiology of A. urinae in Glasgow hospitals and whether the presence of the organism in clinical isolates could be an indicator of undiagnosed urinary tract pathology.Hypothesis/Gap statement. The knowledge gap among clinical staffs on Aerococcus species as emerging pathogens can be filled by understanding its epidemiology and clinical importance.Aim. Describe the epidemiology and clinical importance of Aerococcus urinae.Methodology. We reviewed positive blood cultures with Aerococcus species (2017-2021) and urinary isolates (2021) in Glasgow hospitals. Data were collected from clinical and laboratory database systems.Results. All 22 positive blood cultures were A. urinae and sensitive to amoxicillin, vancomycin, and ciprofloxacin. The median age was 80.5; the majority was male (18). In total, 15/22 (68 %) were diagnosed with urinary tract infection. Thirteen were treated with amoxicillin. No cases of infective endocarditis were noted. One patient was subsequently diagnosed with bladder carcinoma. All 83 positive urinary isolates in 72 patients were A. urinae. One was resistant to amoxicillin; two to ciprofloxacin; all sensitive to nitrofurantoin and vancomycin. The majority was female (43/83), the median age was 80. The commonest risk factors were underlying malignancy including bladder cancer (5/18), chronic kidney disease (17) and diabetes (16). Clinical data was unavailable in 24 episodes. Of these, 41/59 (69.5 %) were diagnosed with urinary tract infection. One patient was subsequently diagnosed with metastatic renal cancer while bladder wall lesions were identified in three patients, two of whom were waiting for an urology review at the time of study. Thirteen patients (18 %) had 1 year recurrent bacteriuria and three were not treated on initial episode.Conclusion. A. urinae are emerging pathogens and are likely to become more common due to advances in laboratory technologies and an ageing population. Clinical teams should be aware of their urological pathogenic potential and not dismiss them as contaminants. Whether Aerococcus infection is a potential indicator for undiagnosed urinary tract malignancy warrants further studies.

[A rare case of arterial thrombosis secondary to Aerococcus viridans aortic endocarditis]. / Un cas rare de thrombose artérielle secondaire à une endocardite aortique à Aerococcus viridans.

Infective endocarditis is an uncommon, yet serious disease responsible for high morbidity and mortality, its incidence is estimated at 3-10 cases per 100,000 person-years. Most infective endocarditis cases emanate from streptococcus and staphylococcus. The incrimination of Aeroccocus viridans is rarely described in the literature and it has a high rate of embolic complication. We report the case of a 31-year-old male patient, with no prior medical history, who was admitted to the cardiology department of Ibn Rochd university center due to a prolonged fever for over 6 months. At admission, his general condition was preserved, he was febrile at 38.7 °C, claudication in the right lower limb with a decrease in the peroneal artery pulse, a graded 4/6 diastolic aortic murmur on auscultation, and no signs of heart failure. The transthoracic echocardiography revealed a type I bicuspid aortic valve disease, severe aortic regurgitation, moderate aortic stenosis, and vegetation implanted on the ventricular side of the right coronary cusp. CT angiography of the lower limbs revealed a bilateral total occlusion of the tibioperoneal trunks extended to the proximal portions of the posterior tibial arteries and peroneal arteries with collateral circulation, endovascular collection, and occlusive calcified plaque of the proximal part of the right anterior tibial artery and the collateral circle. Blood tests showed an inflammatory syndrome. Blood cultures detected Aerococcus viridans. The patient was first put on ceftriaxone, gentamycin, unfractionated heparin, and analgesic-antipyretic when necessary, he was then transferred to the cardiovascular surgery department for replacement of the aortic valve and permeabilization of the lower limbs by the FOGARTY technique. Post-surgical results were satisfying. In conclusion, infective endocarditis secondary to Aerococcus viridans is rare but appears to be virulent because most often discovered at the stage of complications. Therefore, good antibiotic therapy adapted to the antibiogram results in a good prognosis.

Aerococcus urinae - significance of detection in the paediatric urinary tract: a case series.

Aerococcus urinae (A. urinae) is primarily recognized as a common pathogen in the geriatric population, causing urinary tract infection (UTI), sepsis, and endocarditis, predominantly in female patients. In the paediatric population, only a few case reports exist suggesting A. urinae causes malodorous urine in otherwise healthy boys. In this study, we investigated the spectrum of clinical and laboratory presentations of A. urinae detection in children. A retrospective, single-centre, case series including all patients with the detection of A. urinae during a 7-year study period. Patients with detection of A. urinae only in non-urogenital skin swabs were excluded. A total of 40 samples from 33 patients were identified of which 20 patients were included in the final analysis. The median (IQR) age was 6.8 (2.9-9.5) years; 18 (90%) patients were boys. Four patients were diagnosed with a UTI, six had malodorous urine without UTI, three were diagnosed with balanitis and seven showed A. urinae colonization in the urine culture. Urogenital disorders were present in 12 patients. Additional pathogens were detected in 13 patients. Recurrence of detection during our study period was observed in four (20%) patients.  Conclusion: Beyond malodorous urine, A. urinae detection is associated with more severe presentations including UTI in the paediatric population. Pre-existing urogenital disorders were frequent, and therefore, a nephro-urological investigation should be considered in all cases of A. urinae detection in the paediatric population. What is Known: • Aerococcus urinae (A. urinae) is known to be a common pathogen in the geriatric population, causing urinary tract infection (UTI), sepsis, and endocarditis, predominantly in female patients. • In the paediatric population, A. urinae is mainly described as a low-grade pathogen. Some case reports describe A. urinae as the cause of extraordinary malodorous urine in otherwise healthy boys. What is New: • Beyond malodorous urine, A. urinae detection is associated with more severe presentations including UTI in the paediatric population. • A. urinae was mainly detected in boys with pre-existing urogenital disorders; therefore, a nephro-urological investigation should be considered in cases of A. urinae detection in the paediatric population.

Aerococcus urinae, a rare cause of aortic root abscess: a case report.

BACKGROUND: Aerococcus urinae is a bacterium of emerging clinical interest that most commonly causes urinary tract infections (UTI) but can also result in invasive infections. It is a catalase-negative, alpha-haemolytic gram-positive coccus that grows in clusters or tetrads and usually causes urinary tract infections. While rare, infective endocarditis must be considered when A. urinae is isolated in blood culture. The mortality rate of A. urinae infective endocarditis is similar to overall endocarditis mortality. We report a rare case of aortic root abscess caused by A. urinae. CASE PRESENTATION: An 82-year-old Caucasian man presented to hospital with behavioural change and severe malnutrition and was managed for psychotic depression. On day 34 of his inpatient stay, a febrile episode prompted blood cultures, which grew Aerococcus. urinae. Investigations revealed a bicuspid aortic valve, aortic valve endocarditis and aortic root abscess. He also had prostatomegaly. He underwent aortic valve replacement, received 6 weeks of intravenous ceftriaxone and recovered. CONCLUSION: Infective endocarditis should be considered in patients with persistent Aerococcus urinae bacteraemia. Accurate identification with mass spectrometry is recommended to avoid misidentification as staphylococcus, streptococcus or enterococcus, which is a possibility with conventional laboratory methods.

Fatal Aerococcus urinae Aortic Valve Endocarditis with Severe Regurgitation.

BACKGROUND Aerococcus species are a rare cause of endocarditis. Micro-organism identification and antibiotic choice can pose significant management challenges to clinicians who care for patients with this infection. Aerococcus is a gram-positive micro-organism which is commonly misidentified because it shares many similarities with streptococcus and enterococcus species. Aerococcus urinae is usually found to cause urinary tract infections and occurs more frequently in patients with structural urinary tract abnormalities associated with urethral and ureteral obstruction such as kidney stones, phimosis, and prostate hyperplasia. However, it is reported to rarely cause endocarditis. CASE REPORT A 48-year-old man with a history of cocaine abuse and right hip replacement presented to our emergency department with acute encephalopathy. Through a complicated hospital course, he was found to be septic and the bacteria were initially misidentified as an alpha-hemolytic strep before being correctly identified as Aerococcus urinae. He was found to have multiple cerebral, likely septic, embolic infarcts and aortic valve endocarditis. Identification of the micro-organism on blood cultures was challenging, as were decisions about antibiotic choice. He died despite efforts of a multidisciplinary care team. CONCLUSIONS Our case highlights a unique case of Aerococcus endocarditis and shows the difficulty in initially identifying the bacteria. To our knowledge this is the first case reported in the setting of substance abuse. It also highlights the lack of appropriate guideline-directed therapy with regards to antibiotic choices in this group of patients, emphasizing the importance of further research in this regard.

Identification of an Aerococcus urinaeequi isolate by whole genome sequencing and average nucleotide identity analysis.

OBJECTIVES: Identification and classification of microorganisms is one of the most important but difficult and challenging issues in microbiology. Whole genome sequencing (WGS), which can give a thorough understanding for the genome of bacteria strain, has been universally used for studying bacterial classification, evolution, and drug-related resistant genes. We in this study aimed to identify a Gram-positive, microaerophilic, catalase-negative cocci strain named AV208, which has shown resistance to vancomycin, by whole genome's average nucleotide identity (ANI) and high-throughput sequencing technology. METHODS: The AV208 strain was identified by following commercially available identification systems, including API 20 Strep system and Vitek 2 Compact Gram-positive identification system for biochemical phenotypic test. Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF-MS) and 16S rRNA gene sequencing were used for confirmation identification. The whole genome of AV208 was sequenced by using high throughput sequencing technology and ANI between AV208, and its phylogenetic neighbours were analysed by the Orthologous Average Nucleotide Identity Tool (OAT) software. Polymerase chain reaction (PCR) and DNA sequencing were used to investigate the potential molecular mechanism for vancomycin resistance. RESULTS: The AV208 strain was isolated from an ascites sample from a patient with chronic kidney disease who showed extensive resistance to the drugs detected, such as vancomycin with MIC >256 µg/mL. With combination of biochemical phenotypic test, MALDI-TOF-MS and 16S rRNA gene sequencing, the AV208 strain was tentatively identified as an Aercoccus viridans. By using complete genome sequence, we found a 96.24% ANI between strain AV208 and Aerococcus urinaeequi CCUG 28094T, which was higher than that with A. viridans CCUG4311T (94.9%). The consistency of 16S rRNA sequence of strain AV208 was 100% with A. urinaeequi CCUG 28094T and 99.9% with A. viridans CCUG4311T, with only one base difference between them. PCR and sequencing for van genes revealed that AV208 was positive for the vanA gene. A Tn1546 transposon-like structure with vanA gene was found in the genome, which was predicted locating in plasmid, causing vancomycin resistance phenotypes. CONCLUSION: Average nucleotide identity analysis based on whole genome sequence is an accurate and effective method for identification of bacteria, especially for strains that are not discernible by existing methods such as Aerococcus.

Clinical and microbiological characterization of Aerococcus urinae bacteraemias at Helsinki metropolitan area, Finland.

Our objective was to assess the incidence of bacteraemic Aerococcus urinae cases at Helsinki metropolitan area, Finland, from a 6-year study period (2013 to 2018) and to further characterize available cases. The study evaluates the outcome of commonly used cefuroxime treatment and determinate a set of A. urinae in vitro antimicrobial susceptibilities for benzylpenicillin, cefuroxime, and ceftriaxone. Clinical records of A. urinae bacteraemic patients were reviewed retrospectively. Antimicrobial susceptibility testing was performed by disk diffusion, gradient test, and broth microdilution for 139-141 clinical A. urinae isolates. Clinical data of 72/77 patients were combined with the in vitro susceptibilities. We found an increasing number of bacteraemic A. urinae cases within 6-year study period (p = 0.01). The patients were mainly elderly males, and all suffered from underlying conditions. A total of 27.3% of cases (21/77) showed polymicrobial blood cultures. Thirty-day mortality was 22.1%. Cefuroxime was the initial empiric antimicrobial agent given for 66/76 of the patients and treatment outcome was favorable for 20/22 patients who received cefuroxime at least up to day 5. All isolates were susceptible to benzylpenicillin and cefuroxime interpreted by EUCAST breakpoints for Aerococci and PK-PD breakpoints, respectively. MIC determinations gave variable results for ceftriaxone, 2.1-2.9% of the isolates were resistant. To conclude, it seems that the number of bacteraemic Aerococcus urinae cases is increasing at Helsinki metropolitan area, Finland, reflecting the growing blood culture sampling. Clinical A. urinae isolates were susceptible to cefuroxime in vitro. Treatment data indicate that empirical cefuroxime started for possibly urinary tract -derived community-acquired bacteraemia covers A. urinae.

Comparison of Methods for Determining the Antibiotic Susceptibility of Aerococcus Species in a Clinical Setting.

OBJECTIVES: Aerococcus spp are Gram-positive cocci increasingly recognized as uropathogens. The Clinical and Laboratory Standards Institute recently published specific breakpoints for Aerococcus spp (M45, third edition); however, the standardized method used for antimicrobial susceptibility testing (AST) requires media not often maintained in clinical laboratories. The purpose of this study was to evaluate and compare alternative methods of AST for Aerococcus isolates. METHODS: AST was performed on 134 clinical isolates using the Etest on three different types of agar, Vitek 2, and BD Phoenix. These results were compared with broth microdilution using the Sensititre STP6F. RESULTS: Aerococcus exhibited low minimum inhibitory concentrations to benzylpenicillin, meropenem, linezolid, and vancomycin. Variable resistance was seen to levofloxacin, ceftriaxone, and tetracycline. Meropenem and vancomycin met all acceptance criteria with every alternative method tested. Benzylpenicillin and linezolid did not meet essential agreement on any AST method. Tetracycline met the majority of acceptance criteria with the exception of more than 3% very major error when using the Etest on chocolate agar, the Vitek 2, and BD Phoenix. CONCLUSIONS: Overall, the alternate AST method with the highest agreement with broth microdilution was the Etest on Mueller-Hinton agar with 5% sheep blood and may be an optimal alternative to broth microdilution.