Aerococci and aerococcal infections

Aerococcus urinae endocarditis - A case report

Aerococcus urinae is a gram-positive coccus bacterium with a previously underestimated prevalence due to morphological similarities to other gram-positive cocci. Development of newer diagnostic technologies (such as matrix-assisted laser desorption ionization time-of-flight mass spectrometry MALDI-TOF) led to increased recognition of Aerococcus urinae as causative organism mainly for urinary tract infections. Its antibiotic susceptibility poses some challenges, with resistance to some drugs of choice for urinary tract infection. We report a case of a 69-year-old male with infective endocarditis of the mitral valve, who initially presented with fever and shoulder pain to the emergency department. The patient reported an episode of obstructive renal infection two weeks earlier, which was treated with trimethoprim-sulfamethoxazole. The unusual presentation with shoulder pain and a new heart murmur led to suspicion of endocarditis. Urine and blood cultures were positive for Aerococcus urinae, echocardiography revealed vegetations on the mitral valve with severe mitral insufficiency. After two weeks of antibiotic treatment, mitral valve replacement was performed, from which the patient recovered. Reports of Aerococcus urinae endocarditis are still limited in number. On the other side, Aerococcus urinae is an emerging bacterial uropathogen with greater relevance than previously believed. We review the case reports of Aerococcus urinae endocarditis and newest literature about its presentation, course, and clinical management.

Dietary supplementation with a novel acidifier sodium diformate improves growth performance by increasing growth-related hormones levels and prevents Salmonella enterica serovar Pullorum infection in chickens

Since the use of antibiotics as growth promoters in animal feed has been restricted or banned in several countries, finding suitable alternatives is crucial for maintaining animal health. In this study, a novel formate acidifier named sodium diformate (NaDF) was synthesized, and the effects on growth performance and the prevention effects against Salmonella enterica serovar Pullorum infections in chickens were assessed. In broilers, NaDF supplementation improved growth performance, as evidenced by increased body weights and reduced feed conversion ratios. At 38 days of age, NaDF supplementation increased the levels of growth-hormone and ghrelin in the serum, lowered pH values in the gut, improved duodenal morphology, as shown by increased villus length/crypt depth ratios. NaDF also modulated the abundance of beneficial and harmful bacteria without changing the general microbiota diversity and short-chain fatty acids levels, which would be beneficial for maintaining gut homeostasis during its use. NaDF exhibited a broad spectrum of antibacterial activity in vitro. Supplementation with NaDF effectively decreased S. Pullorum colonization in the cecum, liver and spleen in chickens, and mitigated pathological changes in the tissues. Therefore, as a novel acidifier, NaDF can improve chicken growth performance by increasing growth-related hormones levels while maintaining the diversity of gut microbiota, and also resist intestinal bacterial infection. These results provided evidences for the application of NaDF as an effective and safe animal feed in poultry farming.

Therapies in preclinical and in early clinical development for the treatment of urinary tract infections: from pathogens to therapies

INTRODUCTION

Urinary tract infections (UTIs) are a prevalent health challenge characterized by the invasion and multiplication of microorganisms in the urinary system. The continuous exploration of novel therapeutic interventions is imperative. Advances in research offer hope for revolutionizing the management of UTIs and improving the overall health outcomes for individuals affected by these infections.

AREAS COVERED

This review aimed to provide an overview of existing treatments for UTIs, highlighting their strengths and limitations. Moreover, we explored and analyzed the latest therapeutic modalities under clinical development. Finally, the review offered a picture into the potential implications of these therapies on the future landscape of UTIs treatment, discussing possible advancements and challenges for further research.

EXPERT OPINION

Comprehensions into the pathogenesis of UTIs have been gleaned from foundational basic science studies, laying the groundwork for the exploration of novel therapeutic interventions. The primary source of evidence originates predominantly from animal studies conducted on murine models. Nevertheless, the lack of clinical trials interferes the acquisition of robust evidence in humans. The challenges presented by the heterogeneity and virulence of uropathogens add an additional layer of complexity, posing an obstacle that scientists and clinicians are actively grappling with in their pursuit of effective solutions.

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 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.

Culturable and inhalable airborne bacteria in a semiunderground municipal wastewater treatment plant: Distribution, transmission, and health risk assessment

Airborne pathogens constitute a growing threat to global public health. Wastewater treatment plants (WWTPs) are important sources of airborne bacteria, which pose great health risks to the employee and nearby residents. In this study, the distribution, transmission and health risk of the airborne culturable and inhalable bacteria carried by PM2.5 in a semiunderground WWTP were evaluated. The concentrations of culturable bacteria in the air were 21.2-1431.1 CFU/m3, with the main contributions of primary and biological treatments. The relative abundances of culturable and total inhalable bacterial taxa were positively correlated (p < 0.05). However, certain bacteria, including Bacillus, Acinetobacter and Enterococcus, exhibited high reproductive capacity despite their low concentration in the air, suggesting that they can survive and regrow in suitable environments. Transmission modeling revealed that the concentrations of airborne bacteria exponentially decreased with distance from 18.67 to 24.12 copies /m3 at the source to 0.06-0.14 copies /m3 at 1000 m downwind. The risks of 8-h exposure in this WWTP except the outlet exceeded the reference value recommended by WHO, which were primarily dependent on P. aeruginosa, Salmonella, and E. coli. Management practices should consider improved controls for bioaerosols in order to reduce the risk of disease transmission.

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.

Aero to the heart: A case of aortic valve endocarditis caused by Aerococcus Urinae in an elderly woman

Aerococcus urinae (A. urinae) is an infrequent cause of infective endocarditis (IE) and few cases have been reported especially in older women. As of this publication, there are 31 reported cases of IE caused by aerococcus urinae, and of these, 4 are of women, 3 of which are aged > 75 years. Here, we describe a case of A. urinae endocarditis in an 80-year-old woman presenting with worsening fatigue. A diagnosis of native aortic valve endocarditis was established based on characteristic findings of aortic valvular vegetation on transesophageal echocardiogram along with isolation of A. urinae on blood cultures.

Effects of Lactiplantibacillus plantarum and Lactiplantibacillus brevis on fermentation, aerobic stability, and the bacterial community of paper mulberry silage

The present study investigated the dynamic profiles of fermentation quality, aerobic stability, and the bacterial community of paper mulberry silage inoculants without (Control) or with Lactiplantibacillus plantarum (LP), Lactiplantibacillus brevis (LB), or their combination (LPLB), which was screened from naturally fermented paper mulberry. The results showed that the inoculated treatments had significantly reduced neutral detergent fiber, water-soluble carbohydrates, and ammoniacal nitrogen contents compared with the control after 60 days of ensiling (the decreased proportion of LP, LB, and LPLB treatments ranged from 7.33%-11.23%, 9.60%-21.44%, and 21.53%-29.23%, respectively, p < 0.05). The pH value of the LP and LB treatments was significantly lower than that of the control after 60 days of ensiling (4.42 and 4.56 vs. 4.71, p < 0.05). The LP treatment promoted lactic acid accumulation and LAB number compared with the control (66.59% vs. 54.12% and 8.71 log10 CFU/g vs. 8.52 log10 CFU/g, respectively, p < 0.05), and the LB and LPLB treatments inhibited the growth of yeast and mold after 14 days of fermentation. After 5 days of aerobic exposure, both the LB and LPLB treatments increased the aerobic stability time and acetic acid content (from 29 to 75 h and 16.14%-48.72%, respectively, p < 0.05), inhibited the growth of yeast and mold, and did not detect butyric acid. Additionally, the bacteria community of each treatment was dominated by Aerococcus on day 3 of ensilage (accounting for 54.36%-69.31%), while the inoculated treatments reduced the abundance of Aerococcus on day 60 (from 59.73% to 85.16%, p < 0.05), and Lactobacillus became the dominant genus (accounting for 54.57%-70.89%). Inoculation of L. plantarum effectively maintained the acidic environment at the end of the fermentation system by maintaining the abundance of Lactobacillus, maximizing the preservation of dry matter and protein, and reducing protein corruption. Inoculation of L. brevis alone or in combination with L. plantarum significantly inhibited the growth of mold and improved the aerobic stability of paper mulberry silage.

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.

Get the Species Right: Aerococcus viridans is Likely not Responsible

How to cite this article: Rasmussen M, Sunnerhagen T. Get the Species Right: Aerococcus viridans is Likely not Responsible. Indian J Crit Care Med 2022;26(10):1158.

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.

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 neighbors were analyzed 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 28094^T, which was higher than that with A. viridans CCUG4311^T (94.9%). The consistency of 16S rRNA sequence of strain AV208 was 100% with A. urinaeequi CCUG 28094^T and 99.9% with A. viridans CCUG4311^T, 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.

CONCLUSIONS

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.

Aerococcus urinae Infective Endocarditis

Aerococcus urinae is a gram-positive organism frequently found in the urinary tract. It is often mistaken for Streptococcus and Enterococcus based on its appearance. It commonly causes urinary tract infections but has rarely been associated with fatal infective endocarditis and sepsis. We present a case of Aerococcus urinae infective endocarditis and discuss echocardiographic imaging findings and management approach.

An Uncommon Cause of Urinary Tract Infections: A Case Report

Urinary tract infections (UTI) in the elderly are common. UTI ranges in severity from mild disease to severe sepsis. Many organisms can cause UTIs yet many UTIs are caused by the same few organisms. An organism that has been increasingly gaining notoriety for infections is Aerococcus urinae. Aerococcus infections are constantly misdiagnosed due to their difficulty to identify. Here we present a case of an elderly male who was found to have a urinary tract infection with Aerococcus urinaethat progressed into bacteremia, severe sepsis and ultimately death.

Emerging Presence of Culturable Microorganisms in Clinical Samples of the Genitourinary System: Systematic Review and Experience in Specialized Care of a Regional Hospital

The detection of emerging pathogens responsible for genitourinary infections has increased with technological advances. We conducted a systematic review of publications on the involvement of these microorganisms in genitourinary samples, and we also investigated their presence and antibiotic susceptibility in samples from patients at our regional hospital (Granada, Spain). The MEDLINE database was searched up to 31 December 2020, and a cross-sectional descriptive study was performed of results obtained in urine samples and genital exudates from January 2016 through December 2019. The review highlighted the frequent involvement of Neisseria meningitidis in genital infections, while the data on other microorganisms were consistent with findings in our patient series. The emerging microorganisms most often responsible for urinary tract infections were Streptococcus bovis (58.5%) and Gardnerella vaginalis (23.6%) in females, and S. bovis (32.3%), Aerococcus urinae (18.6%), and Corynebacterium spp. (16.9%) in males; those most frequently reported in genital infections were S. viridans (36.4%) in females and C. glucuronolyticum (32.2%) and G. vaginalis (35.6%) in males. In general, emerging pathogens are resistant to conventional antibiotics such as penicillin. However, there has also been an increase in beta-lactam resistance by the S. bovis group and Corynebacterium spp. The systematic review showed that emerging microorganisms are responsible for only a small percentage of genitourinary infections but are of major clinical interest, with a predominance of the S. bovis group, G. vaginalis, Lactobacillus spp., Aerococcus spp., and Corynebacterium spp. in urine samples and of G. vaginalis and C. glucuronolyticum in genital samples. Given the increasing resistance to antibiotics empirically prescribed in patients with genitourinary infections, it is recommended to create an antibiogram in all cases.

Aerococcus viridans Bacteremia: A Rare Case Report from India

Aerococci are fastidious, gram-positive Streptococcus-like organisms widely distributed in the hospital environment. Aerococcus viridans is primarily an opportunistic pathogen. Very few cases of A. viridans bacteremia have been reported so far probably because of its misidentification as streptococci. Here we report an interesting case of A. viridans bacteremia.

How to cite this article: Varshini K, Ganesan V, Charles J. Aerococcus viridans Bacteremia: A Rare Case Report from India. Indian J Crit Care Med 2022;26(1):127–128.

Adult Alphitobius diaperinus Microbial Community during Broiler Production and in Spent Litter after Stockpiling

The facilities used to raise broiler chickens are often infested with litter beetles (lesser mealworm, Alphitobius diaperinus). These beetles have been studied for their carriage of pathogenic microbes; however, a more comprehensive microbiome study on these arthropods is lacking. This study investigated their microbial community in a longitudinal study throughout 2.5 years of poultry production and after the spent litter, containing the mealworms, was piled in pastureland for use as fertilizer. The mean most abundant phyla harbored by the beetles in house were the Proteobacteria (39.8%), then Firmicutes (30.8%), Actinobacteria (21.1%), Tenericutes (5.1%), and Bacteroidetes (1.6%). The community showed a modest decrease in Firmicutes and increase in Proteobacteria over successive flock rotations. The beetles were relocated within the spent litter to pastureland, where they were found at least 19 weeks later. Over time in the pastureland, their microbial profile underwent a large decrease in the percent of Firmicutes (20.5%). The lesser mealworm showed an ability to survive long-term in the open environment within the spent litter, where their microbiome should be further assessed to both reduce the risk of transferring harmful bacteria, as well as to enhance their contribution when the litter is used as a fertilizer.

Multiresistant zoonotic pathogens isolated from goat milk in Northeastern Brazil

Dairy goats play a significant role in socio-economic, cultural, and nutritional development in many countries. This study aimed to identify multiresistant zoonotic pathogens causing mastitis in goats, in addition to characterizing them for the presence of resistance genes and phenotypic resistance. A total of 714 milk samples from 357 lactating goats in 12 farms in the Northeast region of Brazil were analyzed. The isolates were submitted to Matrix Associated Laser Desorption-Ionization - Time of Flight to identify bacterial species, Polymerase Chain Reaction (PCR) to search for resistance genes, and an antibiogram to evaluate the phenotypic profile of antimicrobial resistance. A total of 214 pathogens were identified and bacterial prevalence was 83.29 % (178/214) Staphylococcus spp.; 6.50 % (14/214) Micrococcus luteus; 3.73 % (8/214) Corynebacterium spp.; 2.80 % (6/214) Bacillus spp.; 1.38 % (3/214) Escherichia coli; 0.92 % (2/214) Enterobacter cloacae; 0.46 % (1/214) Aerococcus viridans; 0.46 % (1/214) Morganella morganii; and 0.46 % (1/214) Turicella otitidis. As for gene frequency, 64.60 % (115/178) of the isolates carried the blaZ gene; 37.07 % (66/178) norA; 22.47 % (40/178) tet(L); 16.85 % (30/178) tet(M); 14.04 % (25/178) norB; 8.42 % (15/178) vanA; 7.30 % (13/178) msrA; 6.41 % (5/178) tet-38; 4.49 % (8/178) norC; 2.25 % (4/178) mecA; and 0.56 % (1/178) vanB. Emerging multiresistant zoonotic pathogens are present in the goat milk production chain, especially the coagulase-negative Staphylococcus species that pose a risk to human and animal health.

Aerococcus urinae: A Rare Cause of Endocarditis Presenting With Acute Stroke

Aerococcus urinae is a rare organism infrequently isolated from cultures. Mostly known to cause urinary tract infection, it can cause bacteremia leading to severe urosepsis and infective endocarditis. Embolization is frequently reported with Aerococcus urinae endocarditis (AUE); hence, the presentation is highly variable. Sequelae such as various central nervous system manifestations, sepsis, valvular regurgitation with heart failure and even coronary artery involvement have been reported. We report a case of a 58-year-old man with AUE of the aortic valve, severe aortic regurgitation and embolic stroke as a result of embolization from AUE and ultimately required aortic valve replacement. Our case highlights this rare cause of endocarditis and offers insight into the variability of patient presentation and risk factors to consider.

A mouse model displays host and bacterial strain differences in Aerococcus urinae urinary tract infection

In recent years, the clinical significance of Aerococcus urinae has been increasingly recognized. A. urinae has been implicated in cases of urinary tract infection (UTI; acute cystitis and pyelonephritis) in both male and female patients, ranging from children to older adults. Aerococcus urinae can also be invasive, causing urosepsis, endocarditis, and musculoskeletal infections. Mechanisms of pathogenesis in A. urinae infections are poorly understood, largely due to the lack of an animal model system. In response to this gap, we developed a model of A. urinae urinary tract infection in mice. We compared A. urinae UTI in female C3H/HeN and C57BL/6 mice and compared four clinical isolates of A. urinae isolated from patients with UTI, urgency urinary incontinence, and overactive bladder. Our data demonstrate that host genetic background modulates A. urinae UTI. Female C57BL/6 female mice rapidly cleared the infection. Female C3H/HeN mice, which have inherent vesicoureteral reflux that flushes urine from the bladder up into the kidneys, were susceptible to prolonged bacteriuria. This result is consistent with the fact that A. urinae infections most frequently occur in patients with underlying urinary tract abnormalities or disorders that make them susceptible to bacterial infection. Unlike uropathogens such as E. coli, which cause infection and inflammation both of the bladder and kidneys in C3H/HeN mice, A. urinae displayed tropism for the kidney, persisting in kidney tissue even after clearance of bacteria from the bladder. Aerococcus urinae strains from different genetic clades displayed varying propensities to cause persistent kidney infection. Aerococcus urinae infected kidneys displayed histological inflammation, neutrophil recruitment and increased pro-inflammatory cytokines. These results set the stage for future research that interrogates host-pathogen interactions between A. urinae and the urinary tract.

Summary:Aerococcus urinae clinical isolates are genetically diverse and display differential capacity to cause UTI in a mouse model. Infection was rapidly cleared from the bladder, but persisted and caused inflammation in the kidney.

Background of patients with Aerococcus spp. detected in blood cultures, and drug sensitivity of Aerococcus spp

This study aimed to review the clinical characteristics of patients with Aerococcus spp. detected by blood culture, and drug susceptibility of Aerococcus spp. All cases of Aerococcus spp. determined using blood culture between June 2013 and May 2020 in a single institution were included; patient information (age, sex, comorbidities, outcome, diagnosis, antimicrobial agents) was analyzed. The cohort comprised 25 patients (18 [72%] men and 7 [28%] women; median age, 84.5 [range, 75-87] years). Thirteen (52%) patients had urinary tract infections(UTI) caused by Aerococcus spp. All patients had a favorable prognosis, except 1 who died owing to infective endocarditis. Drug susceptibility testing showed that most isolates were susceptible to β-lactams except 1. However, 24 (96%) cases were resistant to trimethoprim-sulfamethoxazole and 10 (40%) to quinolones. Aerococcus spp. are important causative agents of bacteremia and UTI. The increasing reports of Aerococcus spp. infections could lead to better treatment schemes and facilitate diagnosis.

Urine My Heart: A Case of Aerococcal Endocarditis

An elderly woman with previously known valvular disease presented to the emergency department due to altered mental status. In addition to obtaining an infectious work-up, a bedside echocardiogram was performed and revealed right heart strain prompting a formal echocardiogram evaluation and treatment for a possible pulmonary embolism. Initial laboratory work returned with blood and urine cultures positive for Aerococcus urinae. A transthoracic echocardiogram further revealed new aortic regurgitation. Given this, a transesophageal echocardiogram was completed, confirming new aortic insufficiency as well as findings of infective endocarditis. She did not undergo surgical intervention; however, she was discharged with a plan to continue intravenous antibiotics for six weeks. Although typically seen in genitourinary infections, A. urinae is a rare cause of infective endocarditis and is increasingly identified due to improved speciation techniques. We describe a unique presentation of invasive A. urinae infection to increase awareness and further research on a less commonly encountered bacteria that may present as a urinary tract infection and has the potential to cause invasive disease.

Aerococcus spp infective endocarditis following a prostate biopsy: a case report

We report a rare case of an infective endocarditis by Aerococcus spp in a bioprosthetic aortic valve following a prostate biopsy, in an asymptomatic adult with no additional risk factor for prostate cancer, excepting for age. The diagnosis was based on the presence of vegetations on the bioprosthesis seen on the echocardiogram, positive blood cultures and fever, and a favorable clinical outcome following the treatment with ceftriaxone and gentamicin.

Review of the speculative role of co-infections in Streptococcus suis-associated diseases in pigs

Streptococcus suis is one of the most important bacterial swine pathogens affecting post-weaned piglets, causing mainly meningitis, arthritis and sudden death. It not only results in severe economic losses but also raises concerns over animal welfare and antimicrobial resistance and remains an important zoonotic agent in some countries. The definition and diagnosis of S. suis-associated diseases can be complex. Should S. suis be considered a primary or secondary pathogen? The situation is further complicated when referring to respiratory disease, since the pathogen has historically been considered as a secondary pathogen within the porcine respiratory disease complex (PRDC). Is S. suis a respiratory or strictly systemic pathogen? S. suis is a normal inhabitant of the upper respiratory tract, and the presence of potentially virulent strains alone does not guarantee the appearance of clinical signs. Within this unclear context, it has been largely proposed that co-infection with some viral and bacterial pathogens can significantly influence the severity of S. suis-associated diseases and may be the key to understanding how the infection behaves in the field. In this review, we critically addressed studies reporting an epidemiological link (mixed infections or presence of more than one pathogen at the same time), as well as in vitro and in vivo studies of co-infection of S. suis with other pathogens and discussed their limitations and possibilities for improvement and proposed recommendations for future studies.

What Is fishy in asymptomatic patients?: Co-occurrence of Aerococcus urinae infection in pediatric patient with phimosis

Here we present the first case of Aerococcus urinae isolated from urine sample of a 5-year-old boy from Vojvodina province (Serbia). The patient had predisposing factors related to the susceptibility of genitourinary system to infection. Thus, he reported no complaints related to active urinary infections. Eradication of infection was achieved after 10-day treatment with meropenem. From this case, the question emerges: Is there a possibility that A. urinae infections are neglected in pediatric patients with susceptibility of genitourinary system to infection? Only after wide introduction of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) in competent laboratories, we will be able to give a precise answer.

Aerococcus-Related Infections and their Significance: A 9-Year Retrospective Study

Introduction:

Aerococcus spp. is a Gram-positive, catalase- and oxidase-negative, microaerophilic, nonmotile bacteria species rarely associated with human infections such as arthritis, bacteremia, endocarditis, and meningitis. The bacteria are also often confused with streptococci species or treated as a contaminant.

Patients and Methodology:

We conducted a retrospective, observational cohort study on all patients with Aerococcus spp. isolates in blood samples from July 2010 to June 2019. All categorical data were presented as counts and proportions, whereas continuous data were presented as median and interquartile ranges.

Results:

A total of 20 Aerococcus spp. isolates were identified over the study period of 9 years. Of these, Aerococcus urinae was isolated in 10 (50%), Aerococcus viridans in 6 (30%), and Aerococcus spp. (not speciated) in 4 (20%). The median age was 74.3 years (12 males and 8 females). The two most frequent presentations were fever (15 of 20) and altered mentation (6 of 15). Most of the patients (11 of 15) had at least one predisposing comorbidity related to the urinary tract system (8 with recurrent urinary tract infection, 7 with urinary incontinence, 3 with an indwelling catheter, 2 with renal stones, and 1 each with benign prostatic hyperplasia and a recent cystoscopy). The median white blood cell count was 18,426 cells/mL, median hemoglobin 10.96 g/dL, median platelet count 191,000 cells/μL, median blood urea nitrogen 28.6 mg/dL, and median creatinine 1.54 mg/dL. The urinary tract was the most likely source of bacteremia (10 of 20) based on either imaging findings (5 cases), positive urine culture for Aerococcus spp. (4 cases), or instrumentation history (1 case). In the rest, the cause of bacteremia could not be found. Endocarditis was suspected in 9 out of 20 patients. Transthoracic echocardiography/transesophageal echocardiography (TEE) confirmed 3 cases (2 aortic valves, 1 mitral valve and pacemaker). Interestingly, one case had septic emboli causing a right frontal stroke with a normal TEE and normal Doppler study for deep venous thrombosis. Blood cultures were positive in 35% (7 of 20) with polymicrobial growth, 3 with coagulase-negative staphylococci, 2 with Enterococcus faecalis, and the other 2 each with Diphtheroids spp. and Proteus mirabilis. Of the 20 cases, 9 and 10 required intensive care unit level care and vasopressor support, respectively. Most of the patients were treated for 5–14 days except the 3 cases with infective endocarditis (IE). The median hospital stay duration was 6.55 days with 2 fatalities (2 out of 20 patients).

Conclusion:

Old age and underlying urologic conditions are the best-known risk factors for Aerococcus spp. infection. Recent advances in diagnostic technology have led to an increase in detection of Aerococcus spp.-related infections. The rare occurrence of Aerococcus spp. in human infections and resultant lack of randomized control trials have resulted in a significant degree of clinical uncertainty in the management of Aerococcus spp. IE.

Prosthetic valve endocarditis caused by Aerococcus Urinae

Infective endocarditis (IE) caused by Aerococcus urinae is rare. The true incidence rate of this pathogen is likely underestimated as this is easily misidentified as Staphylococci or Streptococci. It is also associated with increased risk of complications such as systemic emboli. Aerococcus usually affects elderly males with underlying urological conditions. Here we present a case of IE with this rare Aerococcus urinae in a young man with a bioprosthetic aortic valve, despite negative urine cultures.

Usefulness of next-generation DNA sequencing for the diagnosis of urinary tract infection

Acute urinary tract infection (UTI) is a highly common clinical condition. Although bacterial culture is the gold standard diagnostic test, false negative results may be possible, leading to the pathogen being unidentified. In recent years, bacterial DNA sequencing analysis has garnered much attention, but clinical studies are rare in Japan. In this study, we assessed the usefulness of next-generation DNA sequencing (NGS) analysis for acute UTI patients. We thus performed an observational, retrospective case series study. Urine and blood samples were collected from ten acute UTI patients, of whom four had also been diagnosed with urosepsis. Seven variable regions of bacterial 16S rRNA genes were amplified by PCR and then sequenced by IonPGM. The identified bacterial species were compared with those identified using the culture tests and the clinical parameters were analyzed. As a result, the NGS method effectively identified predominant culture-positive bacteria in urine samples. The urine NGS also detected several culture-negative species, which have been reported to be potentially pathogenic. Out of four urosepsis cases, three were pathogen-positive in blood NGS results, while two were pathogen-negative in blood culture. In one sepsis case, although blood culture was negative for Escherichia coli, this species was detected by blood NGS. For non-sepsis cases, however, blood NGS, as well as blood culture, was less effective in detecting bacterial signals. In conclusion, NGS is potentially useful for identifying pathogenic bacteria in urine from acute UTI patients but is less applicable in patients who do not meet clinical criteria for sepsis.

Subacute Aerococcus urinae Infective Endocarditis With Mycotic Aneurysms in a Pediatric Patient: Case Report and Literature Review

Aerococcus urinae has been found to cause urinary tract infection in elderly patients and has been reported as a rare cause of infective endocarditis associated with significant morbidity and death in adults. However, information regarding its occurrence in children is lacking. We report here the case of a pediatric patient with subacute A urinae infective endocarditis with mycotic aneurysms.

Aerococcus urinae Aortitis: A Case Report

Background

Aerococcus urinae is a Gram-positive coccus that is increasingly recognized as a urinary pathogen since the introduction of mass spectrometry for identification of bacteria. We report a case of abdominal aortitis (with aneurysm) caused by A urinae in a male with recurrent urinary tract infections and recently treated A urinae bacteremia. A 63-year-old gentleman with a history of A urinae urosepsis 7 weeks prior, presented to the Emergency Department with thoracolumbar back pain radiating bilaterally into the groin. Radiological and surgical findings were consistent with infective infrarenal aortitis with aneurysm.

Methods

The patient successfully underwent open surgical debridement and reconstruction of the infrarenal aorta with autologous vein graft.

Results

Aerococcus urinae was isolated from excised tissue. The patient completed a 4-week course of intravenous antimicrobial therapy.

Conclusions

Aurinae is a urinary pathogen with the ability to cause severe invasive disease including endovascular infections.

Mitral Valve Endocarditis with Perforation from a Urinary Source: An Unusual Case and Literature Review

Aerococcus urinae (AU) is a rare pathogen, identified as gram-positive, catalase-negative coccus that grows in pairs and clusters which has been reported to mainly cause urinary tract infections (UTI), especially in elderly males. Treatment for this microorganism is usually with beta-lactams although cultures with antibiotic susceptibility testing are imperative. We present a case of AU endocarditis initially treated with IV antibiotics; nevertheless, the patient required emergent mitral valve replacement due to severe mitral insufficiency and perforation. We also present an analysis with high-yield points summarizing epidemiology, risk factors, microbiology, clinical features, diagnostic workup, and management of AU in general and AU endocarditis. Finally, we post a literature review of relevant cases and the impact of different variables associated with it.

Perigenital necrotizing soft tissue infection caused by Aerococcus urinae

Aerococcus urinae can cause severe invasive infections emanating from the urinary tract especially in older males with comorbidities. Here we describe a case of an 80 year-old man with multiple comorbidities presenting with a peri-penile abscess and signs of severe infection. Upon incision A. urinae was isolated in pure culture and the infection was cured by a combination of drainage and antimicrobials. This case demonstrates the potential of A. urinae to cause severe soft tissue infections in predisposed individuals.

Population-based study of early-onset neonatal sepsis in Canada

OBJECTIVE

To determine the incidence, types of organisms and resistance patterns involved in early-onset neonatal sepsis in Canada.

STUDY DESIGN

Early-onset neonatal sepsis cases were identified through the Canadian Paediatric Surveillance Program. Neonates were excluded if they were asymptomatic or if intracranial procedures preceded a positive cerebrospinal fluid culture.

RESULTS

One hundred and twenty-seven cases were identified (0.17 cases per 1000 live births). Group B Streptococcus accounted for 41.7%, Escherichia coli for 35.4%. Antibiotic resistance was present in 33.9% of all cases. 55.6% of E coli cases were resistant, most commonly to ampicillin. Infecting organism species were associated with gestational age, being very low birth weight, time at sepsis presentation, maternal antibiotic prophylaxis and rupture of membranes lasting over 18 hours. Group B Streptococcus was most common in term and E coli in preterm neonates. Twenty-two per cent of E coli cases presented after 48 hours, compared to 6% of Group B Streptococcus cases.

CONCLUSION

We identify a lower rate of early-onset neonatal sepsis than historically suggested, with differing dominant organisms based on gestational ages and other factors, as well as high rates of resistance especially among E coli cases.

The Characteristics and Genome Analysis of vB_AviM_AVP, the First Phage Infecting Aerococcus viridans

Aerococcus viridans is an opportunistic pathogen that is clinically associated with various human and animal diseases. In this study, the first identified A. viridans phage, vB_AviM_AVP (abbreviated as AVP), was isolated and studied. AVP belongs to the family Myoviridae. AVP harbors a double-stranded DNA genome with a length of 133,806 bp and a G + C content of 34.51%. The genome sequence of AVP showed low similarity (<1% identity) to those of other phages, bacteria, or other organisms in the database. Among 165 predicted open reading frames (ORFs), there were only 69 gene products exhibiting similarity (≤65% identity) to proteins of known functions in the database. In addition, the other 36 gene products did not match any viral or prokaryotic sequences in any publicly available database. On the basis of the putative functions of the ORFs, the genome of AVP was divided into three modules: nucleotide metabolism and replication, structural components, and lysis. A phylogenetic analysis of the terminase large subunits and capsid proteins indicated that AVP represents a novel branch of phages. The observed characteristics of AVP indicate that it represents a new class of phages.

Treatment considerations for potential uropathogens detected by precision microbiological testing

PURPOSE

The clinical and microbiological data for urinary tract infections (UTIs) for 6 organisms detected by matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) at community health systems were examined.

SUMMARY

The use of precision microbiological diagnostic testing such as MALDI-TOF and real-time quantitative polymerase chain reaction has increased the ability to detect a wider spectrum of organisms. This has raised questions of the clinical relevance of infrequently encountered organisms, especially when cultured from urine. This article reviews clinical and microbiological data for UTIs for 6 organisms detected by MALDI-TOF at community health systems (Actinotignum schaalii, Chryseobacterium indologenes, Aerococcus urinae, Aerococcus sanguinicola, Corynebacterium riegelii, and Corynebacterium urealyticum). Since little information currently exists, most of the data associating the aforementioned organisms with UTIs were derived from case reports. Although these organisms are more readily identified using precision microbiological diagnostic testing methods, infection should not be assumed based on culture results alone since asymptomatic bacteriuria has been reported. Similar to more common urinary pathogens, clinical correlation is essential. To facilitate treatment, we provide a table of empirical options likely to achieve clinical success based on in vivo and in vitro data. If available, pathogen-specific susceptibility data should be used to direct therapy.

CONCLUSION

Clinical and microbiological data and potential treatment options were presented for 6 traditionally underrecognized organisms that are increasingly being found from urinary specimens. The treatment recommendations should be interpreted cautiously as they were devised through the use of very limited data.

A rare case of Aerococcus urinae infective endocarditis in an atypically young male: case report and review of the literature

BACKGROUND

Aerococcus urinae is a gram-positive, alpha-hemolytic coccus bacterium primarily implicated in less than 1 % of all symptomatic urinary tract infections. Risk factors for disease include male gender, advanced age, and comorbid genitourinary tract pathology. Infections beyond the genitourinary tract are rare, though spondylodiscitis, perineal abscesses, lymphadenitis, bacteremia, meningitis, and endocarditis have been reported. Less than fifty cases of A. urinae infective endocarditis (IE) have been described in the literature. The rare occurrence of A. urinae in human infections and resultant lack of randomized controlled trials have resulted in a significant degree of clinical uncertainty in the management of A. urinae IE.

CASE PRESENTATION

We present an unusual case of a forty-three year-old male with A. urinae infective endocarditis (IE) who was successfully treated with mitral valve replacement and six weeks of penicillin/gentamicin therapy. In addition, we include a comprehensive review of all reported cases of IE due to A. urinae with specific attention to therapeutic regimens and treatment durations.

CONCLUSION

Recent advances in diagnostic technology have led to an increase in the frequency A. urinae is diagnosed. Reviewing cases of Aerococcus urinae infections, their clinical courses and subsequent management can assist future healthcare providers and their patients.

Musculoskeletal infections caused by Aerococcus urinae: a case-based review

Aerococcus are Gram-positive bacteria that have been historically misidentified using standard techniques. We report a case of a 63-year-old man with septic oligoarthritis caused by Aerococcus urinae (isolated in two ankle synovial fluid cultures and in two blood cultures). Due to the lack of evidence found in a search performed to identify similar cases, a systematic review was conducted with the objective to identify and analyze all documented cases of musculoskeletal infections caused by Aerococcus urinae. A total of 8 cases were selected: 6 spondylodiscitis, 1 periarticular hip abscess, and 1 prosthetic hip infection. Similarly, as in other Aerococcus urinae invasive infections, these were presented predominantly in older males with history of urinary tract disease, being identified mostly by sequencing of the 16S rRNA or by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS), with an increasing incidence in the last years and generally with good sensitivity to beta-lactams (aminoglycosides were associated in some cases due to its synergistic effect). Additionally, 4 cases of musculoskeletal infections caused by Aerococcus viridans and 4 cases of Aerococcus urinae with ammoniacal and pervasive malodorous urine were identified; the last was a symptom also present in our case. In this review, we identify a recent increase of musculoskeletal infections caused by Aerococcus urinae, which as well as in series of other invasive infections could be well correlated with an increasing use of more sensible diagnosis methods in clinical laboratories. Therefore, we suggest that these probably will be more frequently diagnosed in the future.

A prospective observational treatment study of aerococcal urinary tract infection

OBJECTIVES

Aerococcus urinae and Aerococcus sanguinicola cause urinary tract infections (UTIs) and antibiotic treatment recommendations are solely based on in vitro findings and limited clinical experience. Our objective was to investigate the effectiveness of different treatment strategies in aerococcal UTI through a prospective observational study.

METHODS

Urine samples with aerococci were identified and patients were enrolled. The aerococci were subjected to Etests. Information on clinical symptoms, and the treatment given, was collected. Patients were interviewed after the conclusion of treatment to assess clinical cure and a control urine culture assessed the microbiological cure.

RESULTS

Of 31,629 urine samples, 144 grew aerococci and fulfilled the inclusion criteria. 91 patients gave consent and the 72 patients with UTI were assessed for treatment outcome. 53 patients had A. urinae UTI, while 19 had A. sanguinicola UTI. Nitrofurantoin was most commonly prescribed, achieving clinical and microbiological success in 71/76% of cases of A. urinae UTI, and 42/50% of cases of A. sanguinicola UTI. Pivmecillinam achieved success in patients with A. urinae cystitis and ciprofloxacin in patients with pyelonephritis.

CONCLUSIONS

Our results support that nitrofurantoin is a valid option for the treatment of cystitis caused by A. urinae.

Genomic characterization, phylogenetic analysis, and identification of virulence factors in Aerococcus sanguinicola and Aerococcus urinae strains isolated from infection episodes

Aerococcus sanguinicola and Aerococcus urinae are emerging pathogens in clinical settings mostly being causative agents of urinary tract infections (UTIs), urogenic sepsis and more seldomly complicated infective endocarditis (IE). Limited knowledge exists concerning the pathogenicity of these two species. Eight clinical A. sanguinicola (isolated from 2009 to 2015) and 40 clinical A. urinae (isolated from 1984 to 2015) strains from episodes of UTIs, bacteremia, and IE were whole-genome sequenced (WGS) to analyze genomic diversity and characterization of virulence genes involved in the bacterial pathogenicity. A. sanguinicola genome sizes were 2.06-2.12 Mb with 47.4-47.6% GC-contents, and 1783-1905 genes were predicted whereof 1170 were core-genes. In case of A. urinae strains, the genome sizes were 1.93-2.44 Mb with 41.6-42.6% GC-contents, and 1708-2256 genes of which 907 were core-genes. Marked differences were observed within A. urinae strains with respect to the average genome sizes, number and sequence identity of core-genes, proteome conservations, phylogenetic analysis, and putative capsular polysaccharide (CPS) loci sequences. Strains of A. sanguinicola showed high degree of homology. Phylogenetic analyses showed the 40 A. urinae strains formed two clusters according to two time periods: 1984-2004 strains and 2010-2015 strains. Genes that were homologs to virulence genes associated with bacterial adhesion and antiphagocytosis were identified by aligning A. sanguinicola and A. urinae pan- and core-genes against Virulence Factors of Bacterial Pathogens (VFDB). Bacterial adherence associated gene homologs were present in genomes of A. sanguinicola (htpB, fbpA, lmb, and ilpA) and A. urinae (htpB, lap, lmb, fbp54, and ilpA). Fifteen and 11-16 CPS gene homologs were identified in genomes of A. sanguinicola and A. urinae strains, respectively. Analysis of these genes identified one type of putative CPS locus within all A. sanguinicola strains. In A. urinae genomes, five different CPS loci types were identified with variations in CPS locus sizes, genetic content, and structural organization. In conclusion, this is the first study dealing with WGS and comparative genomics of clinical A. sanguinicola and A. urinae strains from episodes of UTIs, bacteremia, and IE. Gene homologs associated with antiphagocytosis and bacterial adherence were identified and genetic variability was observed within A. urinae genomes. These findings contribute with important knowledge and basis for future molecular and experimental pathogenicity study of UTIs, bacteremia, and IE causing A. sanguinicola and A. urinae strains.

Clinical Characteristics and Laboratory Identification of Aerococcus Infections: An Australian Tertiary Centre Perspective

Aerococci uncommonly cause urinary tract (UTI) and bloodstream infections (BSI). The clinical characteristics and laboratory identification rates of Aerococcus in the Australian context are unknown. A retrospective observational cohort study of patients with positive Aerococcus cultures between 2010 and 2015 was performed. Patients were analysed according to predefined “asymptomatic bacteriuria,” “UTI,” and “BSI” groups. Forty-seven [40 (85%) for urine and 7 (15%) for blood] isolates were identified [38% male, median age of 79 (IQR 62–85) years], with corresponding identification rates of 24.2/100,000/year for urine (0.02%) and 7.3/100,000/year for blood cultures (0.007%). Since the use of matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-TOF MS) identification rate in urine has increased from 14.7/100,000/year to 32/100,000/year (p = 0.02). For urine isolates, 14 (35%) met the definition for UTI whilst 26 (65%) were “asymptomatic bacteriuria.” Underlying urological abnormalities, catheterisation, and polymicrobial growth were common. Seventy percent of bacteriuria was treated regardless of colonisation or active infection status. Symptomatic patients were more likely to receive treatment (OR 7.2, 95% CI 1.4–35.3). In patients with BSI, 1 (14.2%) had endocarditis and 1 (14.2%) died. The majority of isolates were susceptible to penicillin (11/12 tested, 92%).

A rare case of aerococcus urinae infective endocarditis

Introduction:Aerococcus urinae is a rare cause of infective endocarditis. Aerococcus is a gram positive cocci that is easily misidentified as Staphylococci or Streptococci. The true incidence rate of this pathogen is likely underestimated. Recent advances in laboratory diagnostic methods with matrix-associated laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) have lead to increased recognition of this pathogen in the clinical microbiology lab, and awareness as a cause of infective endocarditis in the infectious disease community.

Case reports: Aerococcus usually affects males with underlying urinary tract conditions. Herein, we report a case of prosthetic aortic valve endocarditis caused by Aerococcus urinae.

Discussion: Our patient was considered high risk for cardiac surgery and was treated successfully with intravenous antibiotics alone for six weeks.

Conclusion: Infective endocarditis should be considered in all cases of Aerococcus bacteremia and appropriate diagnostic evaluations pursued.

Abbreviations: AV: Aortic valve; IE: Infective endocarditis

Aerococcus urinae: An Emerging Cause of Urinary Tract Infection in Older Adults with Multimorbidity and Urologic Cancer

Aerococcus urinae is a rare organism isolated from urine cultures. We present a case of an 80 year-old male with bladder cancer and multimorbidity who developed A. urinae infection. A. urinae may cause simple and complicated UTIs, bacteremia, and endocarditis in older adults with multimorbidity, chronic urinary retention, or indwelling catheters. A. urinae treatment should employ penicillin, amoxicillin, and nitrofurantoin. Due to increasing antibiotic resistance, urine culture should include antibiotic susceptibility testing. Prompt and culture-specific treatment is critical to avoid clinical progression of the infection.

Characteristics of Aerococcus viridans isolated from bovine subclinical mastitis and its effect on milk SCC, yield, and composition

Aerococcus viridians (A. viridans), an environmental Gram-positive bacterium, has been documented to be associated with bovine mastitis. However, its exact role in bovine mastitis and the changes it brings about in milk characteristics are not yet known. The objectives of the current study were to describe the antibiotic resistance of A. viridans from bovine mastitis as well as the correlation between existence of this pathogen in udders and the somatic cell counts (SCC), daily milk yield, and composition of individual cow. One-year sampling for subclinical mastitis composite milk was conducted based on monthly DHI data from September 2013 to August 2014, in a commercial herd located in Beijing, China. All samples were cultured and pathogens were identified using microbiology method. A. viridians isolates were further identified by API identification system and 16S ribosomal RNA (rRNA) sequencing method. Kirby-Bauer disk diffusion method was used to test the antibiotic resistance of A. viridians against kinds of antimicrobial substance. SCC, milk yield, and milk composition data were from monthly Dairy Herd Improvement (DHI) results. Results showed that a total of 279 (16.67%) A. viridans isolates were identified from among 1674 bacterial isolates cultured from milk samples with high SCC. The incidence of mastitis caused by A. viridans was the highest (48-53%) during the summer season. Majority of the isolates were susceptible to most of antimicrobial compounds tested, especially to β-lactams, but were found to be resistant (50-90%) to aminoglycosides, sulfonamides, and tetracycline. The average SCC of the A. viridans infected cows was significantly higher (1000.0 × 10³ cells/mL) (P < 0.01) as compared to healthy cows (72.4 × 10³ cells/mL) and daily milk yield decreased (P > 0.05) by 1.86 kg/day. Reductions were also observed in fat content (P > 0.05), lactose (P < 0.01), and total solids (P > 0.05), whereas protein content increased significantly (P < 0.01) in milk samples of cows infected with A. viridans. The results of this study suggest that A. viridans could be considered as an emerging aetiological agent of bovine subclinical mastitis wherein it exerts an effect on SCC, milk yield, and composition.

A rare case of perineal abscess caused by aerococcus urinae

Aerococcus urinae, a previously misidentified pathogen, has become increasingly recognized to cause severe and even fatal infections. Aerococcus-related perineal abscess infections have not previously been reported in the literature. Most reported cases of infections caused by Aerococcus are urinary tract infections, bacteremia, and even rare cases of endocarditis. We report an unusual case of a perineal abscess caused by Aerococcus urinae.

Bactericidal activity of penicillin, ceftriaxone, gentamicin and daptomycin alone and in combination against Aerococcus urinae

Aerococcus urinae can cause severe infections (bacteraemia and endocarditis) that are associated with high mortality. However, data on the bactericidal and synergistic activity for clinically implemented antibiotics are scarce. Time-kill analyses were performed on two clinical isolates (AU1 and AU2) and the reference strain ATCC 700306 for penicillin (PG), ceftriaxone (CRO), gentamicin (GEN), daptomycin (DAP) and their combinations. AU1 and AU2 were CRO-resistant (MICs, 2 µg/mL) and ATCC 700306 was high-level GEN-resistant (MIC, 512 µg/mL), whereas all strains were PG- and DAP-susceptible (MICs, ≤0.125 and ≤1 µg/mL, respectively). CFU counts were determined at various time points from 0 to 48 h. All experiments were performed at 0.5×, 1×, 2× and 4× MIC. PG and CRO were not bactericidal for all strains, whereas DAP exhibited bactericidal activity at all concentrations for AU2 and ATCC 700306. The combination of PG or CRO with GEN was bactericidal for AU1 and AU2 at antibiotic concentrations ≥1× MIC. Bactericidal synergism was detected for PG or CRO combined with GEN in the two clinical isolates. PG plus CRO showed non-bactericidal synergism for ATCC 700306. DAP with GEN was synergistic at 1× MIC for AU1, whereas the killing activity of DAP was too pronounced to detect potential synergism in AU2. The combination of PG or CRO with GEN is synergistic and bactericidal. Moreover, these in vitro data suggest that DAP may represent a potential bactericidal treatment alternative against A. urinae. This finding could be important for the treatment of patients with a β-lactam allergy or renal insufficiency.