''Peptostreptococcus'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

anaerobic Anaerobic means "living, active, occurring, or existing in the absence of free oxygen", as opposed to aerobic which means "living, active, or occurring only in the presence of oxygen." Anaerobic may also refer to: *Adhesive#Anaerobic, Anaerobic ad ...

Gram-positive In bacteriology, gram-positive bacteria are bacteria that give a positive result in the Gram stain test, which is traditionally used to quickly classify bacteria into two broad categories according to their type of cell wall. The Gram stain is ...

, non-

spore In biology, a spore is a unit of sexual reproduction, sexual (in fungi) or asexual reproduction that may be adapted for biological dispersal, dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores fo ...

forming

bacteria Bacteria (; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of Prokaryote, prokaryotic microorganisms. Typically a few micr ...

. The

cells Cell most often refers to: * Cell (biology), the functional basic unit of life * Cellphone, a phone connected to a cellular network * Clandestine cell, a penetration-resistant form of a secret or outlawed organization * Electrochemical cell, a d ...

are small,

spherical A sphere (from Ancient Greek, Greek , ) is a surface (mathematics), surface analogous to the circle, a curve. In solid geometry, a sphere is the Locus (mathematics), set of points that are all at the same distance from a given point in three ...

, 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 An antimicrobial is an agent that kills microorganisms (microbicide) or stops their growth (bacteriostatic agent). Antimicrobial medicines can be grouped according to the microorganisms they are used to treat. For example, antibiotics are used aga ...

drugs. ''Peptostreptococcus'' is a normal

inhabitant In law and conflict of laws, domicile is relevant to an individual's "personal law", which includes the law that governs a person's status and their property. It is independent of a person's nationality. Although a domicile may change from time t ...

of the healthy lower reproductive tract of women.

Pathogenesis

''Peptostreptococcus'' species are

commensal Commensalism is a long-term biological interaction (symbiosis) in which members of one species gain benefits while those of the other species neither benefit nor are harmed. This is in contrast with mutualism, in which both organisms benefit f ...

organisms in humans, living predominantly in the mouth, skin,

gastrointestinal The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The tract is the largest of the body's systems, after the cardiovascular system. ...

, vagina and

urinary tract The human urinary system, also known as the urinary tract or renal system, consists of the kidneys, ureters, bladder, and the urethra. The purpose of the urinary system is to eliminate waste from the body, regulate blood volume and blood pressu ...

s, and are members of the

gut microbiota Gut microbiota, gut microbiome, or gut flora are the microorganisms, including bacteria, archaea, fungi, and viruses, that live in the digestive tracts of animals. The gastrointestinal metagenome is the aggregate of all the genomes of the g ...

. Under

immunosuppressed Immunosuppression is a reduction of the activation or efficacy of the immune system. Some portions of the immune system itself have immunosuppressive effects on other parts of the immune system, and immunosuppression may occur as an adverse react ...

or traumatic conditions these organisms can become

pathogen In biology, a pathogen (, "suffering", "passion" and , "producer of"), in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a Germ theory of d ...

ic, as well as septicemic, harming their host. ''Peptostreptococcus'' can cause brain, liver, breast, and lung

abscess An abscess is a collection of pus that has built up within the tissue of the body, usually caused by bacterial infection. Signs and symptoms of abscesses include redness, pain, warmth, and swelling. The swelling may feel fluid-filled when pre ...

es, as well as generalized

necrotizing Necrosis () is a form of cell injury which results in the premature death of cells in living tissue by autolysis. The term "necrosis" came about in the mid-19th century and is commonly attributed to German pathologist Rudolf Virchow, who is ...

soft tissue

infection An infection is the invasion of tissue (biology), tissues by pathogens, their multiplication, and the reaction of host (biology), host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmis ...

s. They participate in mixed

anaerobic infection Anaerobic infections are caused by anaerobic bacteria. Obligately anaerobic bacteria do not grow on solid media in room air (0.04% carbon dioxide and 21% oxygen); facultatively anaerobic bacteria can grow in the presence or absence of air. Micro ...

s, a term which is used to describe infections that are caused by multiple bacteria that do not require or may even be harmed by oxygen. ''Peptostreptococcus'' species are susceptible to beta-lactam antibiotics. They are isolated with high frequency from all specimen sources. Anaerobic gram-positive cocci such as ''Peptostreptococcus'' are the second most frequently recovered anaerobes and account for approximately one quarter of anaerobic isolates found. Most often anaerobic gram-positive cocci are usually recovered mixed in with other anaerobic or aerobic bacteria from various infections at different sites of the human body. This contributes to the difficulty of isolating ''Peptostreptococcus'' organisms.Finegold SM. Anaerobic Bacteria in Human Disease. Orlando, Fla: Academic Press; 1977.

Infections

''Peptostreptococcus'' species that are found in clinical infections were once part of the genus formerly known as ''

Peptococcus ''Peptococcus'' is a Gram-positive bacterium genus in the family Peptococcaceae. Species in the genus are part of the human microbiome, especially in the bacteria that form the gut flora. They are part of the flora of the mouth, upper respirato ...

''. ''Peptostreptococcus'' is the only genus among anaerobic gram-positive cocci that is encountered in clinical infections. As such, ''Peptostreptococcus'' species are viewed as being clinically significant anaerobic cocci. Other similar clinically significant anaerobic cocci include '' Veillonella'' species (gram-negative cocci), and microaerophilic streptococci (aerotolerant). Anaerobic gram-positive cocci include various clinically significant species of the genus ''Peptostreptococcus''.Brook I. Anaerobic Infections. In: Diagnosis and Management. 4th Edition. New York: Informa Healthcare USA Inc.; 2007. The species of anaerobic gram-positive cocci isolated most commonly include ''Peptostreptococcus magnus'', ''Peptostreptococcus asaccharolyticus'', ''Peptostreptococcus anaerobius'', ''Peptostreptococcus prevotii'', and ''Peptostreptococcus micros''. Anaerobic gram-positive cocci that produce large amounts of lactic acid during the process of carbohydrate fermentation were reclassified as ''Streptococcus parvulus'' and '' Streptococcus morbillorum'' from ''Peptococcus'' or ''Peptostreptococcus''. Most of these organisms are anaerobic, but some are microaerophilic. Due to a large amount of new research done on the human microbe and more information on bacteria, many species of bacteria have been renamed and re-classified. Based on DNA homology and whole-cell polypeptide-pattern study findings supported by phenotypic characteristics, the DNA homology group of microaerobic streptococci that was formerly known as ''Streptococcus anginosus'' or ''Streptococcus milleri'' is now composed of three distinct species: ''S. anginosus'', ''S. constellatus'', and ''S. intermedius''. The microaerobic species ''S. morbillorum'' was transferred into the genus '' Gemella''. A new species within the genus ''Peptostreptococcus'' is ''Peptostreptococcus hydrogenalis''; it contains the indole-positive, saccharolytic strains of the genus. ''Peptostreptococcus'' infections occur in/on all body sites, including the CNS, head, neck, chest, abdomen, pelvis, skin, bone, joint, and soft tissues. Adequate therapy must be taken against infections, or it could result in clinical failures. Peptostreptoccocci are often overlooked and they are very difficult to isolate, appropriate specimen collection is required. Peptostreptococci grow slowly which makes them increasingly resistant to antimicrobrials. The most common ''Peptostreptococcus'' species found in infections are ''P. magnus'' (18% of all anaerobic gram-positive cocci and microaerophilic streptococci), ''P. asaccharolyticus'' (17%), ''P. anaerobius'' (16%), ''P. prevotii'' (13%), ''P. micros'' (4%), ''P. saccharolyticus'' (3%), and ''P. intermedius'' (2%). ''P. magnus'' were highly recovered in bone and chest infections. ''P. asaccharolyticus'' and ''P. anaerobius'' had the highest recovery rate in obstetrical/gynecological and respiratory tract infections and wounds. When anaerobic and facultative cocci were recovered most of the infection were polymicrobial. Most patients from whom microaerophilic streptococci were recovered in

pure culture A microbiological culture, or microbial culture, is a method of multiplying microbial organisms by letting them reproduce in predetermined culture medium under controlled laboratory conditions. Microbial cultures are foundational and basic diag ...

had abscesses (e.g., dental, intracranial, pulmonary), bacteremia, meningitis, or conjunctivitis. ''P. magnus'' is the most commonly isolated anaerobic cocci and is often recovered in pure culture. Other common Peptostreptococci in the different infectious sites are ''P. anaerobius'' which occurs in oral infections; ''P. micros'' in respiratory tract infections, ''P. magnus'', ''P. micros'', ''P. asaccharolyticus'', ''P. vaginalis'', and ''P. anaerobius'' in skin and soft tissue infections; ''P. magnus'' and ''P. micros'' in deep organ abscesses; ''P. magnus'', ''P. micros'', and ''P. anaerobius'' in gastrointestinal tract-associated infections; ''P. magnus'', ''P. micros'', ''P. asaccharolyticus'', ''P. vaginalis'', ''P. tetradius'', and ''P. anaerobius'' in female genitourinary infections; and ''P. magnus'', ''P. asaccharolyticus'', ''P. vaginalis'', and ''P. anaerobius'' in bone and joint infections and leg and foot ulcers. Many infections caused by ''Peptostreptococcus'' bacteria are synergistic. Bacterial synergy, the presence of which is determined by mutual induction of sepsis enhancement, increased mortality, increased abscess inducement, and enhancement of the growth of the bacterial components in mixed infections, is found between anaerobic gram-positive cocci and their aerobic and anaerobic counterparts. The ability of anaerobic gram-positive cocci and microaerophilic streptococci to produce capsular material is an important virulence mechanism, but other factors may also influence the interaction of these organisms in mixed infections. Although anaerobic cocci can be isolated from infections at all body sites, a predisposition for certain sites has been observed. In general, ''Peptostreptococcus'' species, particularly ''P. magnus'', have been recovered more often from subcutaneous and soft tissue abscesses and diabetes-related foot ulcers than from intra-abdominal infections. ''Peptostreptococcus'' infections occur more often in chronic infections.

Frequency of infections

It is difficult to determine the exact frequency of ''Peptostreptococcus'' infections because of inappropriate collection methods, transportation, and specimen cultivation. ''Peptostreptococcus'' infections are most commonly found in patients who have had or have chronic infections. Patients who have predisposing conditions are shown to have 5% higher recovery rate of the bacteria in blood cultures. Of all anaerobic bacteria recovered at hospitals from 1973 to 1985, anaerobic gram-positive cocci accounted for 26% of it. The infected sited where these organisms were found in the greatest abundance were obstetrical and gynecological sites (35%), bones (39%) cysts (40%), and ears (53%). Occasionally found in other places such as abdomen,

lymph node A lymph node, or lymph gland, is a kidney-shaped organ of the lymphatic system and the adaptive immune system. A large number of lymph nodes are linked throughout the body by the lymphatic vessels. They are major sites of lymphocytes that includ ...

s, bile, and eyes. Frequency of infections is greater in developing countries because treatment is often slow, or it is impossible to get the adequate treatment, but mortality due to ''Peptostreptococcus'' infections have decreased in the last 30 years and will continue to do so due to better treatment. All ages are susceptible to ''Peptostreptococcus'' infections, however children are more likely to get head and neck infections.

Infection types

Skin and soft tissue infections

Anaerobic gram-positive cocci and microaerophilic streptococci are often recovered in polymicrobial skin and soft tissue infections, such as gangrene, fasciitis, ulcers, diabetes-related foot infections, burns, human or animal bites, infected cysts, abscesses of the breast, rectum, and anus. Anaerobic gram-positive cocci and microaerophilic streptococci are generally found mixed with other aerobic and anaerobic bacteria that originate from the mucosal surface adjacent to the infected site or that have been inoculated into the infected site. ''Peptostreptococcus'' spp. can cause infections such as gluteal decubitus ulcers, diabetes-related foot infections, and rectal abscesses. Anaerobic gram-positive cocci and microaerophilic streptococci are part of the normal skin microbiota, so it is hard to avoid contamination by these bacteria when obtaining specimens.

CNS infections

CNS infections can be isolated from

subdural empyema Subdural empyema is a form of empyema – a collection of pus, in the subdural space. Bacterial or occasionally fungal infection of the skull bones or air sinuses can spread to the subdural space, producing a subdural empyema. The underlying arac ...

and brain abscesses which are a result of chronic infections. Also isolated from sinuses, teeth and mastoid. 46% of 39 brain abscesses in one study showed anaerobic gram-positive cocci and microaerophilic streptococci.

Upper respiratory tract and dental infections

There is a high rate of anaerobic cocci colonization which accounts for the organisms significance in these infections. Anaerboci gram-positive cocci and micraerophilic streptococci are often recovered in these infections. They have been recovered in 15% of patients with chronic mastoiditis. When Peptostreptococci and other anaerobes predominate, aggressive treatment of acute infection can prevent chronic infection. When the risk of anaerobic infection is high, as with intra-abdominal and post-surgical infections, proper antimicrobial prophylaxis may reduce the risk 90% of the time, other organisms were mixed in with the anaerobic gram-positive cocci and microaerophilic streptococci. This includes ''Streptococcus'' species, and ''Staphylococcus aureus''. ''Peptostreptococcus micros'' has a moderate association with periodontal disease.

Bacteremia and endocarditis

Peptostreptococci can cause fatal endocarditis, paravalvular abscess, and

pericarditis Pericarditis () is inflammation of the pericardium, the fibrous sac surrounding the heart. Symptoms typically include sudden onset of sharp chest pain, which may also be felt in the shoulders, neck, or back. The pain is typically less severe whe ...

. The most frequent source of bacteremia due to ''Peptostreptococcus'' are infections of the

oropharynx The pharynx (: pharynges) is the part of the throat behind the mouth and nasal cavity, and above the esophagus and trachea (the tubes going down to the stomach and the lungs respectively). It is found in vertebrates and invertebrates, though its ...

, lower respiratory tract, female genital tract, abdomen, skin, and soft tissues. Recent gynecological surgery,

immunosuppression Immunosuppression is a reduction of the activation or efficacy of the immune system. Some portions of the immune system itself have immunosuppressive effects on other parts of the immune system, and immunosuppression may occur as an adverse react ...

, dental procedures, infections of the female genital tract, abdominal and soft tissue along with gastrointestinal surgery are predisposing factors for bacteremia due to ''peptostreptococcus''. Microaerophilic streptococci typically account for 5-10% of cases of endocarditis; however, Peptostreptococci have only rarely been isolated.

Anaerobic pleuropulmonary infections

Anaerobic gram-positive cocci and microaerophilic streptococci are most frequently found in aspiration pneumonia, empyema, lung abscesses, and

mediastinitis Mediastinitis is inflammation of the tissues in the mid-chest, or mediastinum. It can be either acute or chronic. It is thought to be due to four different etiologies: * direct contamination * hematogenous or lymphatic spread * extension of i ...

. These bacteria account for 10-20% of anaerobic isolated recovered from pulmonary infections. It is difficult to obtain appropriate culture specimens. It requires a direct lung puncture, or the use of trans-tracheal aspiration.

Abdominal infections

Anaerobic gram-positive cocci are part of the normal gastrointestinal microbiota. They are isolated in approximately 20% of specimens from intra-abdominal infections, such as peritonitis. Found in abscesses of the liver, spleen, and abdomen. Like in upper respiratory tract and dental infections, anaerobic gram-positive cocci are recovered mixed with other bacteria. In this case they are mixed with organisms of intestinal origin such as E coli, bacteroides fragilis group, and clostridium species.

Female pelvic infections

Anaerobic gram-positive cocci are frequently isolated from anaerobically infected bones and joints., they accounted for 40% of anaerobic isolates of osteomyelitis caused by anaerobic bacteria and 20% of anaerobic isolates of arthritis caused by anaerobic bacteria. P magnus and P prevotii are the predominant bone and joint isolates. Management of these infections requires prolonged courses of antimicrobials and is enhanced by removal of the foreign material. ''Peptostreptococcus'' species are part of the microbiota of the lower reproductive tract of women.

Causes of infection

Infections with anaerobic gram-positive cocci and microaerophilic streptococci are often caused by: * Trauma *

Immunodeficiency Immunodeficiency, also known as immunocompromise, is a state in which the immune system's ability to fight infectious diseases and cancer is compromised or entirely absent. Most cases are acquired ("secondary") due to extrinsic factors that aff ...

* Steroid therapy *

Vascular disease Vascular disease is a class of diseases of the vessels of the circulatory system in the human body, body, including blood vessels – the arteries and veins, and the lymphatic vessels. Vascular disease is a subgroup of cardiovascular disease. Diso ...

Malignancy Malignancy () is the tendency of a medical condition to become progressively worse; the term is most familiar as a characterization of cancer. A ''malignant'' tumor contrasts with a non-cancerous ''benign'' tumor in that a malignancy is not ...

* Reduced blood supply * Previous surgery * Presence of a foreign body *

Sickle cell anemia Sickle cell disease (SCD), also simply called sickle cell, is a group of inherited haemoglobin-related blood disorders. The most common type is known as sickle cell anemia. Sickle cell anemia results in an abnormality in the oxygen-carrying ...

Diabetes Diabetes mellitus, commonly known as diabetes, is a group of common endocrine diseases characterized by sustained high blood sugar levels. Diabetes is due to either the pancreas not producing enough of the hormone insulin, or the cells of th ...

Treatment

When ''Peptostreptococci'' and other anaerobes predominate, aggressive treatment of acute infection can prevent chronic infection. When the risk of anaerobic infection is high, as with intra-abdominal and post-surgical infections, proper antimicrobial prophylaxis may reduce the risk. Therapy with antimicrobials (e.g.,

aminoglycoside Aminoglycoside is a medicinal and bacteriologic category of traditional Gram-negative antibacterial medications that inhibit protein synthesis and contain as a portion of the molecule an amino-modified glycoside (sugar). The term can also refer ...

trimethoprim-sulfamethoxazole Trimethoprim/sulfamethoxazole, sold under the trade names Bactrim, Cotrim (a short form of the British Approved Name, Co-trimoxazole) and Septra, among others, is a fixed-dose combination antibiotic medication used to treat a variety of bacte ...

, older

quinolone Quinolone may refer to: * 2-Quinolone * 4-Quinolone * Quinolone antibiotic Quinolone antibiotics constitute a large group of broad-spectrum bacteriocidals that share a bicyclic core structure related to the substance 4-quinolone. They ar ...

s) often does not eradicate anaerobes.

Taxonomy

As of 2022, there are 5 species validly published in the genus ''Peptostreptococcus'', with several species formerly being described, that have been moved to a more accurate genus. ;Species formerly described in ''Peptostreptococcus'' * Order Coriobacteriales ** Family Atopobiaceae *** Genus '' Lancefieldella'': '' P. parvulus'', first moved to '' Atopobium'' in 1993, reassigned in 2018. * Order Eggerthellales ** Family

Eggerthellaceae The Eggerthellaceae are a family of Gram-positive bacteria, Gram-positive, rod- or coccus-shaped Actinomycetota. It is the sole family within the order ''Eggerthellales.'' The name ''Eggerthellaceae'' is derived from the Latin term ''Eggerthella ...

*** Genus '' Slackia'': '' P. heliotrinreducens'', reassigned in 1999. * Order

Eubacteriales The Eubacteriales are an order of bacteria placed within the class Clostridia. Phylogeny The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN) and National Center for Biotechnology Informa ...

** Family

Lachnospiraceae The Lachnospiraceae are a family of obligately anaerobic, variably spore-forming bacteria in the order Eubacteriales that ferment diverse plant polysaccharides to short-chain fatty acids (butyrate, acetate) and alcohols (ethanol). These bacteria ...

*** Genus '' Blautia'': '' P. productus'', first moved to '' Ruminococcus'' (

Oscillospiraceae Oscillospiraceae, also commonly called Ruminococcaceae, is a family of bacteria in the class Clostridia. All Oscillospiraceae are obligate anaerobes. However, members of the family have diverse shapes, with some rod-shaped and others cocci. With ...

) in 1994, reassigned in 2008. ** Family

Peptoniphilaceae The Peptoniphilaceae are a family of bacteria in the class Clostridia. Taxonomy Not validly published genera in Peptoniphilaceae. * ''Khoudiadiopia'', with the type species ''K. massiliensis''. Proposed in 2017, but not validly published. * ''La ...

*** Genus ''

Anaerococcus Anaerococcus is a genus of bacteria. Its type species is '' Anaerococcus prevotii''. These bacteria are Gram-positive and strictly anaerobic. The genus Anaerococcus was proposed in 2001. Its genome was sequenced in August 2009. The genus Anaeroco ...

'': '' P. hydrogenalis'', '' P. lactolyticus'', '' P. octavius'', '' P. prevotii'', '' P. tetradius'', '' P. vaginalis'', reassigned in 2001. *** Genus '' Finegoldia'': '' P. magnus'', reassigned in 2000. *** Genus '' Gallicola'': '' P. barnesae'', reassigned in 2001. *** Genus '' Parvimonas'': '' P. micros'', reassigned in 2006. *** Genus ''

Peptoniphilus ''Peptoniphilus'' is a genus of bacteria in the phylum Bacillota (Bacteria). Etymology The name ''Peptoniphilus'' derives from:Neo-Latin noun ''peptonum'', peptone; Neo-Latin adjective ''philus'' from Greek adjective ''philos (φίλος)'' mean ...

'': '' P. asaccharolyticus'', '' P. harei'', '' P. indolicus'', '' P. ivorii'', '' P. lacrimalis'', reassigned in 2001.

Phylogeny

The currently accepted taxonomy is based on the

List of Prokaryotic names with Standing in Nomenclature List of Prokaryotic names with Standing in Nomenclature (LPSN) is an online database that maintains information on the naming and taxonomy of prokaryotes, following the taxonomy requirements and rulings of the International Code of Nomenclatu ...

(LPSN) and

National Center for Biotechnology Information The National Center for Biotechnology Information (NCBI) is part of the National Library of Medicine (NLM), a branch of the National Institutes of Health (NIH). It is approved and funded by the government of the United States. The NCBI is lo ...

(NCBI)

References

External links

Peptostreptococcus infections
from eMedicine. {{Taxonbar, from=Q3543267 Peptostreptococcaceae Gut flora bacteria Bacterial vaginosis Bacteria genera Taxa described in 1936 Pathogenic bacteria