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The taxonomic status of Pediococcus urinaeequi is described, and the transfer of the species to the genus Aerococcus with the name Aerococcus urinaeequi comb. nov. is proposed, on the basis of the analysis of 16S rRNA gene sequence and DNA-DNA hybridization data.
A polyphasic characterization of Aerococcus urinae is presented. In this study the intraspecies relationships between 26 strains of varying geographical origin were examined by phenotypic tests, ribotyping and multilocus enzyme electrophoresis. The results demonstrated two main phenotypic patterns that could be distinguished in tests for hydrolysis of aesculin, and acid production from amygdalin and salicin. Strains were either negative (n=19) or positive (n=6) in these tests. One strain had a deviating pattern. Heterogeneity within the 19 pattern I strains was demonstrated especially by phenotypic tests (acid production from ribose, mannitol, sorbitol, sucrose and D-arabitol) and by multilocus enzyme electrophoresis. However, DNA sequence analysis of the 16S rRNA (n=7) and gyrB genes (n=3) from strains representing the two main patterns showed no variation in sequences among strains. Comparison of A. urinae and representatives of related taxa by 16S rDNA sequence analysis showed that the taxon is related to, but distinct from, other Aerococcus spp.
Aerococci are only occasionally isolated from urinary tract specimens. A 4-month' survey revealed 29 patients suspected of urinary tract infection (UTI), from whom an Aerococcus-like organism (ALO) was isolated in significant numbers from urinary tract specimens and singly in 11 cases. Approximately 0.8% of all urinary tract specimens examined during the period yielded growth of ALO. The median age of patients was 75 years. Half of the patients were found to have conditions predisposing to UTI. 9 of 11 patients without indwelling catheter, having ALO isolated in pure culture from the urine, showed one or more typical signs of UTI (fever, dysuria and/or pollakisuria and pyuria). A phenotypic comparison was made between 29 strains of ALO and 6 related organisms, including Aerococcus viridans, Streptococcus faecium, Streptococcus sanguis, Streptococcus bovis, Streptococcus Group Q and Streptococcus Group R. ALO and A. viridans showed many similarities, but, owing to characteristic differences with regard to colony morphology, biochemical reactions and antibiotic susceptibility pattern, the strains were easily separated.
A total of 244 strains of Aerococcus, Enterococcus, and Streptococcus species were tested by the RapID STR system (Innovative Diagnostic Systems Inc., Atlanta, Ga.) for identification. Strains were identified without additional tests or with additional conventional tests suggested by the IDS compendium manual. Our data indicate that the RapID STR system identifies 89% of the beta-hemolytic Streptococcus species if serological procedures are used in conjunction with the rapid physiological procedures. Of the group D streptococci, 98% of the Enterococcus species and 100% of the group D non-Enterococcus species were correctly identified. Of the commonly occurring viridans group Streptococcus species, 93% were correctly identified, and 79% of the less frequently occurring viridans group Streptococcus species were correctly identified. All of the Streptococcus pneumoniae and Aerococcus strains tested were correctly identified.
Two cases of invasive infections with aerococcus-like organisms (ALO) are presented: an 81-year-old man with fatal endocarditis and a 63-year-old man with urosepticemia. No antigenic relationship was found between ALO and Aerococcus viridans (NCTC 8251) in crossed immunoelectrophoretic assay.
Aerococcus urinae, an uncommon urinary tract pathogen, was recently shown to cause septicaemia and endocarditis in a few patients in Denmark and the Netherlands. In Austria this is the first report of a fatal course of endomyocarditis by Aerococcus urinae, associated with multiple septic infarcts.
A decade ago we discovered a hitherto unrecognized Aerococcus-like organism (ALO) in urine specimens from patients with urinary tract infection. Further microbiological and clinical investigations enabled us to classify it as a human pathogen also causing urogenic septicaemia and endocarditis, the latter often with lethal outcome. The organism is now designated Aerococcus urinae.
Four cases are described of Aerococcus viridans endocarditis with favorable outcome, focusing on the clinical picture. Extracardiac findings (e.g. neurological, renal, musculoskeletal, intra-abdominal) in infective endocarditis (IE) have been recognized more frequently in recent years, and may delay the diagnosis and have a negative influence on the prognosis. Aerococcus viridans, a very rare microorganism causing invasive infections, has been associated with bacteremia, septic arthritis, and especially IE. As expected, the strains isolated were susceptible to penicillins, trimethoprim/sulfamethoxazole, and glycopeptides. Medical therapy was sufficient to cure IE in two patients, while two others required surgical intervention.
Representatives of the normal microflora from genus Aerococcus, in particular strain Aerococcus viridans 167 isolated from breast milk are studied for their effect on biological properties of Staphylococcus aureus in vitro and in vivo. It is established that the number of viable cells of the staphylococcus cultivated in the presence of antagonists in the beef-extract agar decreases progressively with each following passage, the population dying after the seventh-eight passage. Electronograms fix deep changes in the cell ultrastructure. A degree of changes in biological properties depends on the duration of the antagonist action. The results obtained reveal one of the mechanisms of the antagonistic action of aerococci-antagonists producing hydrogen peroxide.
A 20-year-old woman was found to have septic arthritis of the hip due to Aerococcus viridans. This organism closely resembles Streptococcus viridans, but forms gram positive tetrads rather than chains in broth media. The organism has been reported rarely to cause endocarditis and one case of osteomyelitis has been observed. To our knowledge septic arthritis due to Aerococcus viridans has not been previously reported.
Nine coagulase-negative Staphylococci and Aerococcus viridans were tested for bacterial antagonism. Seven of the nine of the coagulase-negative Staphylococci and Aerococcus viridans inhibited the growth of four Staph. hyicus, three Staph. aureus strains and some other Gram-positive bacteria, including Streptococcus group A and D, Corynebacteria, but none of the Gram-negative and yeast was inhibited on agar media. There was also production of inhibitory substances in different types of liquid media but no antagonistic activity was observed on Millipore membrane. The inhibition was not due to the pH change of media in which the producers were grown, but due to production of inhibitory substances tentatively classed as antibiotics.
Dihydroxyacetone phosphate is essential for the synthesis of polyhydroxylated compounds used as components or precursors of active pharmaceutical substances, such as antibiotics or glycosidase inhibitors. Dihydroxyacetone phosphate was produced by enzymatic oxidation of L-alpha-glycerophosphate in the presence of glycerophosphate oxidase or Aerococcus viridans coimmobilized with a hydrogen peroxide-decomposing enzyme. The microencapsulation of A. viridans with catalase in sodium alginate showed a conversion of 98.5%; the conversion percentage remained constant in all five runs. Liquid chromatography of the product revealed that the product peak corresponded to that of the dihydroxyacetone phosphate internal standard. This indicated a high degree of product purity.
Glycerophosphate oxidase was purified from Aerococcus viridans cells by phase partitioning in Triton X-114, ammonium sulfate fractionation, FPLC ion-exchange chromatography and FPLC hydrophobic-interaction chromatography. The purification achieved from a crude extract of A. viridans was 38-fold with a 32% recovery of activity. Under the growth conditions used, A. viridans strain CECT 978 proved to be an excellent glycerophosphate-oxidase producer, with enzyme production 2,800-fold greater than that described in the literature for the same microorganism. The culture medium used in the present work is that commonly used for cultivation of this microorganism, except that an H2O2-decomposing enzyme was added. The addition of catalase to the growth medium had a clear effect on the growth rate. Furthermore, methylglyoxal, a metabolite that is formed enzymatically from triose phosphates, was found to be an inactivator of glycerophosphate oxidase activity.
Aerococcus urinae is a rare cause of urinary tract infections, mainly in elderly men with underlying urinary tract pathologies. In addition, it has been described as a pathogen in balanitis, soft tissue infections, septicemia and endocarditis. To date ten cases of A. urinae endocarditis have been reported in the literature with a high rate of mortality (7/10) and morbidity, as two out of three survivors suffered from neurovascular complications. Here we present the case of an additional patient who was successfully treated with surgical valve replacement and antibiotic therapy consisting of ceftriaxone and netilmicin for 6 weeks. Furthermore, we review all reported cases of A. urinae endocarditis with emphasis on predisposing factors and therapeutic options.
Lyophilized whole cells and isolated cell walls from Aerococcus viridans (Gaffkya homari) grown on a synthetic medium containing benzylpenicillin, and either L-[epsilon-15N]lysine or 15N-ammonium ion as the only source of label, have been studied using cross-polarization magic-angle spinning 15N nuclear magnetic resonance. The lysine is incorporated directly into protein and cell-wall peptidoglycan and was used to measure cell-wall cross-links. The ammonium ion acts as a non-specific label monitoring general metabolism. Inhibition of cell-wall cross linking by penicillin occurs, but may not be the exclusive cause of cell death and lysis in this microorganism. Instead, the disruption of the mechanism for control of peptidoglycan synthesis probably is a contributing factor.
Lactate oxidase was purified from cells of Aerococcus viridans by a procedure which utilized ammonium sulfate fractionation, DEAE Sepharose CL-6B chromatography, and Sephadex G-100 chromatography. The final preparation was homogeneous by SDS-polyacrylamide gel electrophoresis. The enzyme appears to be a tetramer with a subunit molecular weight of 44,000 and utilizes FMN as a cofactor. The enzyme was highly specific for L-lactate. D-lactate, glycolate, and D,L-2-hydroxybutyrate were not oxidized by the enzyme but were competitive inhibitors. The enzyme could be irreversibly inactivated by incubation with bromopyruvate. This inactivation appears to involve a covalent modification near the active site of the enzyme; however, the flavin cofactor is not the site of this modification.
The capsular polysaccharide from Aerococcus viridans var. homari has been investigated, using n.m.r. spectroscopy, methylation analysis, and specific degradations as the main methods. The polysaccharide is composed of tetrasaccharide repeating-units having the following structure. (Formula; see text) In this structure, D-QuiN stands for 2-amino-2,6-dideoxy-D-glucose (quinovosamine). Two of the three acidic sugars found, namely, L-altruronic acid and 4-O-[(S)-1-carboxyethyl]-D-glucose, have not been found in any other natural source. As evident from the n.m.r. spectra, the L-altruronic acid is not present in the 1C4 conformation, but flips to a conformation close to this on carboxyl reduction.
A polymerase chain reaction/oligonucleotide probe method was developed for the specific identification of the Gram-positive bacterium Aerococcus viridans. Primers for the enzymatic amplification reaction were designed from specific sequences within the 16S rRNA. The method was also highly sensitive and 10 cfu of A. viridans could be detected in 5 h although the reliability of detection was poor in mixed cultures with Escherichia coli.