Clostridium innocuum | |
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Scientific classification | |
Domain: | Bacteria |
Phylum: | Bacillota |
Class: | Clostridia |
Order: | Eubacteriales |
Family: | Clostridiaceae |
Genus: | Clostridium |
Species: | C. innocuum |
Binomial name | |
Clostridium innocuum Smith and King 1962 | |
Clostridium innocuum is an anaerobic, non-motile, gram-positive bacterium that reproduces by sporulation. [1] While there are over 130 species of Clostridium, C. innocuum is the third most commonly isolated. Although it is not normally considered an aggressive human pathogen, it has been isolated in some disease processes. C. innocuum and other Clostridium line the oropharynx and gastrointestinal tract, and are considered normal gut flora. [2]
Anaerobic gram-positive bacilli affecting human beings are generally divided into two distinct groups, those that form spores (Clostridium spp.) and those that do not form spores. Within the spore-forming group of Clostridium species, some are very pathogenic or toxigenic ( C. perfringens ) while others are rarely pathogenic. Identification and differentiation between anaerobic gram-positive bacteria in a clinical laboratory can be a very difficult task[ citation needed ]. When the class Clostridia was separated into Clostridia and Erysipelotrichia, Clostridium innocuum was reassigned as Erysipelotrichia Erysipelotrichales Erysipelotrichaceae Erysipelotrichaceae incertae sedis [3] , but is still commonly referred to as Clostridium innocuum.
Clostridium innocuum forms white, glossy, raised colonies and exhibits a chartreuse fluorescence. It is a small, non-flagellated rod that does not swarm. However, human intestinal isolates can often exhibit twitching motility. [4] C. innocuum falls into the saccharolytic, non-proteolytic group of Clostridium spp. and is negative for gelatin hydrolysis, lecithinase, lipase, indole, urea, and nitrate. It is positive for glucose fermentation, esculin and produces oval, terminal spores. [5]
Although Clostridium innocuum are often present and harmless in healthy people, they have been isolated in various infections and predominantly in patients that are immunocompromised as an opportunistic bacteria. In one case, C. innocuum was isolated in an infected hematoma adjacent to a transplanted kidney in a 38-year-old hepatitis C patient. Originally, the bacteria was misidentified as another Clostridium species but was eventually correctly identified. This led the authors to state that C. innocuum infection post transplant may be severely underestimated. [6] C. innocuum has also been implicated in cases of fatal bacteremia as reported in a retrospective study done by Newark Beth Israel Medical Center. Patients that succumbed to the infection (100% mortality) had underlying disease states (malignancy, diabetes or liver disease). While clostridial species only account for 2% of clinical bacteremia, C innocuum was among the three most commonly isolated bacteria in this study. [7] C. innocuum has also been isolated in patients with recurrent diarrhea who had prior C. difficile associated diarrhea. [8] One case of fatal bacterial endocarditis was also found in the literature. This is possibly the only confirmed case of C. innocuum endocarditis involving the pulmonary and tricuspid valves resulting in multiple emboli and death. [9] C. innocuum is also commonly the signature bacterial species found in creeping fat from Crohn's disease patients. [4]
In a study that identified clostridial species using commercial identification kits, it was found that as many as 10% of C. innocuum isolates were somewhat resistant to clindamycin. Most strains were found to be only moderately susceptible to vancomycin (MIC at which 90% of strains are inhibited, 4 micrograms/mL). [10] In another study, where C innocuum was positively identified by gas-liquid chromatography, resistance to vancomycin was seen in all 28 strains isolated. All other clostridial species were at least 8 times more susceptible to vancomycin than C. innocuum, suggesting an intrinsic vancomycin resistance mechanism in C. innocuum. [11]
Clostridium botulinum is a gram-positive, rod-shaped, anaerobic, spore-forming, motile bacterium with the ability to produce botulinum toxin, which is a neurotoxin.
Bloodstream infections (BSIs) are infections of blood caused by blood-borne pathogens. The detection of microbes in the blood is always abnormal. A bloodstream infection is different from sepsis, which is characterized by severe inflammatory or immune responses of the host organism to pathogens.
Clostridioides difficile infection, also known as Clostridium difficile infection, is a symptomatic infection due to the spore-forming bacterium Clostridioides difficile. Symptoms include watery diarrhea, fever, nausea, and abdominal pain. It makes up about 20% of cases of antibiotic-associated diarrhea. Antibiotics can contribute to detrimental changes in gut microbiota; specifically, they decrease short-chain fatty acid absorption which results in osmotic, or watery, diarrhea. Complications may include pseudomembranous colitis, toxic megacolon, perforation of the colon, and sepsis.
Clostridium perfringens is a Gram-positive, bacillus (rod-shaped), anaerobic, spore-forming pathogenic bacterium of the genus Clostridium. C. perfringens is ever-present in nature and can be found as a normal component of decaying vegetation, marine sediment, the intestinal tract of humans and other vertebrates, insects, and soil. It has the shortest reported generation time of any organism at 6.3 minutes in thioglycolate medium.
Vancomycin-resistant Staphylococcus aureus (VRSA) are strains of Staphylococcus aureus that have acquired resistance to the glycopeptide antibiotic vancomycin. Bacteria can acquire resistance genes either by random mutation or through the transfer of DNA from one bacterium to another. Resistance genes interfere with the normal antibiotic function and allow bacteria to grow in the presence of the antibiotic. Resistance in VRSA is conferred by the plasmid-mediated vanA gene and operon. Although VRSA infections are uncommon, VRSA is often resistant to other types of antibiotics and a potential threat to public health because treatment options are limited. VRSA is resistant to many of the standard drugs used to treat S. aureus infections. Furthermore, resistance can be transferred from one bacterium to another.
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.
Peptostreptococcus is a genus of anaerobic, Gram-positive, non-spore forming bacteria. The cells are small, spherical, and can occur in short chains, in pairs or individually. They typically move using cilia. Peptostreptococcus are slow-growing bacteria with increasing resistance to antimicrobial drugs. Peptostreptococcus is a normal inhabitant of the healthy lower reproductive tract of women.
Paeniclostridium sordellii is a rare anaerobic, gram-positive, spore-forming rod with peritrichous flagella that is capable of causing pneumonia, endocarditis, arthritis, peritonitis, and myonecrosis. C. sordellii bacteremia and sepsis occur rarely. Most cases of sepsis from C. sordellii occur in patients with underlying conditions. Severe toxic shock syndrome among previously healthy persons has been described in a small number of C. sordellii cases, most often associated with gynecologic infections in women and infection of the umbilical stump in newborns. It has also been described in post-partum females, medically induced abortions, injection drug users and trauma cases. So far, all but one documented post-partum females who contracted C. sordellii septicaemia have died, and all but one woman who contracted the bacterium post-abortion have died.
Oritavancin, sold under the brand name Orbactiv among others, is a semisynthetic glycopeptide antibiotic medication for the treatment of serious Gram-positive bacterial infections. Its chemical structure as a lipoglycopeptide is similar to vancomycin.
Enterococcus faecium is a Gram-positive, gamma-hemolytic or non-hemolytic bacterium in the genus Enterococcus. It can be commensal in the gastrointestinal tract of humans and animals, but it may also be pathogenic, causing diseases such as neonatal meningitis or endocarditis.
Clostridium septicum is a gram positive, spore forming, obligate anaerobic bacterium.
Staphylococcus capitis is a coagulase-negative species (CoNS) of Staphylococcus. It is part of the normal flora of the skin of the human scalp, face, neck, scrotum, and ears and has been associated with prosthetic valve endocarditis, but is rarely associated with native valve infection.
Clostridium cadaveris is an enteric, gas-forming, motile, strictly anaerobic gram-positive bacterium of the genus Clostridium. First described by Klein in 1899, it was noted to be the most prominent bacteria during human decomposition; historically it was described as "putrefying flora".
Anaerobic infections are caused by anaerobic bacteria. Obligately anaerobic bacteria do not grow on solid media in room air ; facultatively anaerobic bacteria can grow in the presence or absence of air. Microaerophilic bacteria do not grow at all aerobically or grow poorly, but grow better under 10% carbon dioxide or anaerobically. Anaerobic bacteria can be divided into strict anaerobes that can not grow in the presence of more than 0.5% oxygen and moderate anaerobic bacteria that are able of growing between 2 and 8% oxygen. Anaerobic bacteria usually do not possess catalase, but some can generate superoxide dismutase which protects them from oxygen.
Clostridium tertium is an anaerobic, motile, gram-positive bacterium. Although it can be considered an uncommon pathogen in humans, there has been substantial evidence of septic episodes in human beings. C. tertium is easily decolorized in Gram-stained smears and can be mistaken for a Gram-negative organism. However, C.tertium does not grow on selective media for Gram-negative organisms.
Aerococcus urinae is a Gram-positive bacterium associated with urinary tract infections.
Pasteurella canis is a Gram-negative, nonmotile, penicillin-sensitive coccobacillus of the family Pasteurellaceae. Bacteria from this family cause zoonotic infections in humans, which manifest themselves as skin or soft-tissue infections after an animal bite. It has been known to cause serious disease in immunocompromised patients.
Clostridioides difficile is a bacterium known for causing serious diarrheal infections, and may also cause colon cancer. It is known also as C. difficile, or C. diff, and is a Gram-positive species of spore-forming bacteria. Clostridioides spp. are anaerobic, motile bacteria, ubiquitous in nature and especially prevalent in soil. Its vegetative cells are rod-shaped, pleomorphic, and occur in pairs or short chains. Under the microscope, they appear as long, irregular cells with a bulge at their terminal ends. Under Gram staining, C. difficile cells are Gram-positive and show optimum growth on blood agar at human body temperatures in the absence of oxygen. C. difficile is catalase- and superoxide dismutase-negative, and produces up to three types of toxins: enterotoxin A, cytotoxin B and Clostridioides difficile transferase. Under stress conditions, the bacteria produce spores that are able to tolerate extreme conditions that the active bacteria cannot tolerate.
Cellulosimicrobium cellulans is a Gram-positive bacterium from the genus of Cellulosimicrobium. Cellulosimicrobium cellulans can cause rare opportunistic infections. The strain EB-8-4 of this species can be used for stereoselective allylic hydroxylation of D-limonene to (+)-trans-carveol.
Christensenella hongkongensis is a species of clinically relevant gram-positive coccobacilli, first isolated from patients in Hong Kong and Canada in 2006. Although the species remains relatively rare, it has a high mortality rate of up to 50%. Christensenella is thought to be broadly distributed globally, as it has been isolated from patient blood cultures around the world including Hong Kong, South Korea, New Zealand, Canada, Sweden, France and Italy. Fewer than 15 cases of C. hongkongensis have been observed worldwide.