| Aerococcus urinae | |
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| Aerococcus urinae on blood agar [1] | |
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| Microscopy of Aerococcus urinae with gram stain, showing gram positive cocci. [1] | |
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| Species: | A. urinae |
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| Aerococcus urinae | |
Aerococcus urinae is a Gram-positive bacterium associated with urinary tract infections.
Aerococcus urinae is a member of the bacterial genus Aerococcus . The bacterium is a Gram-positive, catalase-negative coccus growing in clusters. Isolates of this genus were originally isolated in 1953 from samples collected in the air and dust of occupied rooms and were distinguished by their tetrad cellular arrangements. [2] Later, it was found in the urine of patients with urinary tract infections [3] and in 1992, A. urinae was assigned as distinct species. [4] Due to difficulties in the biochemical identification of A. urinae in clinical microbiological laboratories, the incidence of infections with this bacterium has likely been underestimated and secure identification relies on genetic techniques like 16S ribosomal subunit sequencing or mass spectroscopic methods such as MALDI-TOF. [5]
A. urinae may also cause invasive infections including sepsis originating from the urinary tract and infective endocarditis, especially in elderly men with underlying urinary tract diseases. [6] [7]
A. urinae is sensitive to many commonly used antibiotics such as penicillins, cephalosporins, and vancomycin. Nitrofurantoin has been reported to be effective in one series of 42 clinical isolates. [8] The bacterium can form biofilms on foreign materials and can aggregate human platelets, two features of potential importance for the disease causing capacity of this organism. [9]
A. urinae is the most common aerococcus isolated from invasive human infections whereas Aerococcus sanguinicola is isolated from human urine as often as A. urinae. [10]
A biofilm is an syntrophic community of microorganisms in which cells stick to each other and often also to a surface. These adherent cells become embedded within a slimy extracellular matrix that is composed of extracellular polymeric substances (EPSs). The cells within the biofilm produce the EPS components, which are typically a polymeric combination of extracellular polysaccharides, proteins, lipids and DNA. Because they have three-dimensional structure and represent a community lifestyle for microorganisms, they have been metaphorically described as "cities for microbes".
Enterococcus is a large genus of lactic acid bacteria of the phylum Bacillota. Enterococci are gram-positive cocci that often occur in pairs (diplococci) or short chains, and are difficult to distinguish from streptococci on physical characteristics alone. Two species are common commensal organisms in the intestines of humans: E. faecalis (90–95%) and E. faecium (5–10%). Rare clusters of infections occur with other species, including E. casseliflavus, E. gallinarum, and E. raffinosus.
Acinetobacter is a genus of Gram-negative bacteria belonging to the wider class of Gammaproteobacteria. Acinetobacter species are oxidase-negative, exhibit twitching motility, and occur in pairs under magnification.
Proteus mirabilis is a Gram-negative, facultatively anaerobic, rod-shaped bacterium. It shows swarming motility and urease activity. P. mirabilis causes 90% of all Proteus infections in humans. It is widely distributed in soil and water. Proteus mirabilis can migrate across the surface of solid media or devices using a type of cooperative group motility called swarming. Proteus mirabilis is most frequently associated with infections of the urinary tract, especially in complicated or catheter-associated urinary tract infections.
Pyelonephritis is inflammation of the kidney, typically due to a bacterial infection. Symptoms most often include fever and flank tenderness. Other symptoms may include nausea, burning with urination, and frequent urination. Complications may include pus around the kidney, sepsis, or kidney failure.
Enterobacter is a genus of common Gram-negative, facultatively anaerobic, rod-shaped, non-spore-forming bacteria of the family Enterobacteriaceae. Cultures are found in soil, water, sewage, feces and gut environments. It is the type genus of the order Enterobacterales. Several strains of these bacteria are pathogenic and cause opportunistic infections in immunocompromised hosts and in those who are on mechanical ventilation. The urinary and respiratory tracts are the most common sites of infection. The genus Enterobacter is a member of the coliform group of bacteria. It does not belong to the fecal coliforms group of bacteria, unlike Escherichia coli, because it is incapable of growth at 44.5 °C in the presence of bile salts. Some of them show quorum sensing properties.
Staphylococcus lugdunensis is a coagulase-negative member of the genus Staphylococcus, consisting of Gram-positive bacteria with spherical cells that appear in clusters.
Staphylococcus saprophyticus is a Gram-positive coccus belonging to the genus Staphylococcus. S. saprophyticus is a common cause of community-acquired urinary tract infections.
Pseudomonas aeruginosa is a common encapsulated, Gram-negative, aerobic–facultatively anaerobic, rod-shaped bacterium that can cause disease in plants and animals, including humans. A species of considerable medical importance, P. aeruginosa is a multidrug resistant pathogen recognized for its ubiquity, its intrinsically advanced antibiotic resistance mechanisms, and its association with serious illnesses – hospital-acquired infections such as ventilator-associated pneumonia and various sepsis syndromes. P. aeruginosa is able to selectively inhibit various antibiotics from penetrating its outer membrane - and has high resistance to several antibiotics, according to the World Health Organization P. aeruginosa poses one of the greatest threats to humans in terms of antibiotic resistance.
Stenotrophomonas maltophilia is an aerobic, nonfermentative, Gram-negative bacterium. It is an uncommon bacterium and human infection is difficult to treat. Initially classified as Bacterium bookeri, then renamed Pseudomonas maltophilia, S. maltophilia was also grouped in the genus Xanthomonas before eventually becoming the type species of the genus Stenotrophomonas in 1993.
Streptococcus bovis is a species of Gram-positive bacteria that in humans is associated with urinary tract infections, endocarditis, sepsis, and colorectal cancer. S. gallolyticus is commonly found in the alimentary tract of cattle, sheep, and other ruminants, and may cause ruminal acidosis or feedlot bloat. It is also associated with spontaneous bacterial peritonitis, a frequent complication occurring in patients affected by cirrhosis. Equivalence with Streptococcus equinus has been contested.
Pseudomonas stutzeri is a Gram-negative soil bacterium that is motile, has a single polar flagellum, and is classified as bacillus, or rod-shaped. While this bacterium was first isolated from human spinal fluid, it has since been found in many different environments due to its various characteristics and metabolic capabilities. P. stutzeri is an opportunistic pathogen in clinical settings, although infections are rare. Based on 16S rRNA analysis, this bacterium has been placed in the P. stutzeri group, to which it lends its name.
Bacteriuria is the presence of bacteria in urine. Bacteriuria accompanied by symptoms is a urinary tract infection while that without is known as asymptomatic bacteriuria. Diagnosis is by urinalysis or urine culture. Escherichia coli is the most common bacterium found. People without symptoms should generally not be tested for the condition. Differential diagnosis include contamination.
Chronic bacterial prostatitis is a bacterial infection of the prostate gland. It should be distinguished from other forms of prostatitis such as acute bacterial prostatitis and chronic pelvic pain syndrome (CPPS).
Aerococcus is a genus in the phylum Bacillota (Bacteria). The genus was first identified in 1953 from samples of air and dust as a catalase-negative, gram-positive coccus that grew in small clusters. They were subsequently found in hospital environments and meat-curing brines. It has been difficult to identify as it resembles alpha-hemolytic Streptococcus on blood agar plates and is difficult to identify by biochemical means. Sequencing of 16S rRNA has become the gold standard for identification, but other techniques such as MALDI-TOF have also been useful for identifying both the genus and species.
Escherichia coli is a gram-negative, rod-shaped bacterium that is commonly found in the lower intestine of warm-blooded organisms (endotherms). Most E. coli strains are harmless, but pathogenic varieties cause serious food poisoning, septic shock, meningitis, or urinary tract infections in humans. Unlike normal flora E. coli, the pathogenic varieties produce toxins and other virulence factors that enable them to reside in parts of the body normally not inhabited by E. coli, and to damage host cells. These pathogenic traits are encoded by virulence genes carried only by the pathogens.
Neisseria bacilliformis is a bacterium commonly found living as a commensal in the mucous membranes of mammals. However, depending on host immunocompetence, there have been documented cases of N. bacilliformis infections of the respiratory tract and oral cavity thus making it an opportunistic pathogen. It was originally isolated from patients being treated in a cancer center. Rarely, a more serious infection such as endocarditis can occur often as a result of a predisposing condition.
Aerococcus sanguinicola is a member of the bacterial genus Aerococcus and is a Gram-positive, catalase-negative coccus growing in clusters. This species was defined in 2001 and has since then been increasingly recognized as a pathogen causing urinary tract infections and also invasive infections including infective endocarditis. Commercially available biochemical tests fail to properly identify A. sanguinicola and correct identification can be achieved through genetic or mass spectroscopic methods, such as matrix-assisted laser desorption/ionization time of flight (MALDI-TOF). A. sanguinicola is, with A. urinae, the most common aerococcus isolated from urine, but from blood, A. urinae is much more commonly encountered.
Staphylococcus pseudintermedius is a gram positive coccus bacteria of the genus Staphylococcus found worldwide. It is primarily a pathogen for domestic animals, but has been known to affect humans as well. S. pseudintermedius is an opportunistic pathogen that secretes immune modulating virulence factors, has many adhesion factors, and the potential to create biofilms, all of which help to determine the pathogenicity of the bacterium. Diagnoses of Staphylococcus pseudintermedius have traditionally been made using cytology, plating, and biochemical tests. More recently, molecular technologies like MALDI-TOF, DNA hybridization and PCR have become preferred over biochemical tests for their more rapid and accurate identifications. This includes the identification and diagnosis of antibiotic resistant strains.
Corynebacterium xerosis is a Gram-positive, rod-shaped bacterium in the genus Corynebacterium. Although it is frequently a harmless commensal organism living on the skin and mucus membranes, C. xerosis is also a clinically-relevant opportunistic pathogen that has been attributed to a number of different infections in animals and humans. However, its actual prominence in human medicine is up for debate due to early difficulties distinguishing it from other Corynebacterium species in clinical isolates.
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