Stenotrophomonas maltophilia

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Stenotrophomonas maltophilia clinical isolates on McConkey agar DSC 0701 Steno.jpg
Stenotrophomonas maltophilia clinical isolates on McConkey agar

Stenotrophomonas maltophilia
Scientific classification
S. maltophilia
Binomial name
Stenotrophomonas maltophilia
Palleroni & Bradbury 1993

Pseudomonas maltophilia(ex Hugh and Ryschenkow 1961) Hugh 1981
Xanthomonas maltophilia(Hugh 1981) Swings et al. 1983
Pseudomonas hibiscicolaMoniz 1963
Pseudomonas betelicorrig. (Ragunathan 1928) Savulescu 1947


Stenotrophomonas maltophilia is an aerobic, nonfermentative, Gram-negative bacterium. It is an uncommon bacterium and human infection is difficult to treat. [1] Initially classified as Bacterium bookeri, [2] 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. [3] [4]

Aerobic organism

An aerobic organism or aerobe is an organism that can survive and grow in an oxygenated environment. In contrast, an anaerobic organism (anaerobe) is any organism that does not require oxygen for growth. Some anaerobes react negatively or even die if oxygen is present.

Human Species of hominid

Humans are the only extant members of the subtribe Hominina. Together with chimpanzees, gorillas, and orangutans, they are part of the family Hominidae. A terrestrial animal, humans are characterized by their erect posture and bipedal locomotion; high manual dexterity and heavy tool use compared to other animals; open-ended and complex language use compared to other animal communications; larger, more complex brains than other animals; and highly advanced and organized societies.

Infection invasion of a host by disease-causing organisms

Infection is the invasion of an organism's body tissues by disease-causing agents, their multiplication, and the reaction of host tissues to the infectious agents and the toxins they produce. Infectious disease, also known as transmissible disease or communicable disease, is illness resulting from an infection.

S. maltophilia is slightly smaller (0.7–1.8 × 0.4–0.7 μm) than other members of the genus. They are motile due to polar flagella, and grow well on MacConkey agar producing pigmented colonies. S. maltophilia is catalase-positive, oxidase-negative (which distinguishes it from most other members of the genus) and has a positive reaction for extracellular DNase.[ citation needed ]

Chemical polarity electrostatic property of a molecule

In chemistry, polarity is a separation of electric charge leading to a molecule or its chemical groups having an electric dipole moment, with a negatively charged end and a positively charged end.

MacConkey agar culture medium used in microbiology

MacConkey agar is an indicator, a selective and differential culture medium for bacteria designed to selectively isolate Gram-negative and enteric bacilli and differentiate them based on lactose fermentation. The crystal violet and bile salts inhibit the growth of Gram-positive organisms which allows for the selection and isolation of gram-negative bacteria. Enteric bacteria that have the ability to ferment lactose can be detected using the carbohydrate lactose, and the pH indicator neutral red.

Catalase protein-coding gene in the species Homo sapiens

Catalase is a common enzyme found in nearly all living organisms exposed to oxygen. It catalyzes the decomposition of hydrogen peroxide to water and oxygen. It is a very important enzyme in protecting the cell from oxidative damage by reactive oxygen species (ROS). Likewise, catalase has one of the highest turnover numbers of all enzymes; one catalase molecule can convert millions of hydrogen peroxide molecules to water and oxygen each second.

S. maltophilia is ubiquitous in aqueous environments, soil, and plants; it has also been used in biotechnology applications. [5] In immunocompromised patients, S. maltophilia can lead to nosocomial infections.

Biotechnology Use of living systems and organisms to develop or make useful products

Biotechnology is the broad area of biology involving living systems and organisms to develop or make products, or "any technological application that uses biological systems, living organisms, or derivatives thereof, to make or modify products or processes for specific use". Depending on the tools and applications, it often overlaps with the (related) fields of molecular biology, bio-engineering, biomedical engineering, biomanufacturing, molecular engineering, etc.


S. maltophilia frequently colonizes humid surfaces such as the tubes used in mechanical ventilation and indwelling urinary catheters as well as medical devices such as suction catheters and endoscopes. [2] Infection is usually facilitated by the presence of prosthetic material (plastic or metal), and the most effective treatment is removal of the prosthetic material (usually a central venous catheter or similar device). S. maltophilia adheres strongly and forms biofilm on plastic surfaces although these abilities may vary greatly between strains. Hydrophobicity was correlated to successful adhesion and biofilm formation on polystyrene surfaces. [6] S. maltophilia frequently co-occurs and forms multispecies biofilms with Pseudomonas aeruginosa . S. maltophilia substantially influences the architecture of P. aeruginosa structures, causing development of extended filaments. These changes arise due to diffusible signalling factor encoded by S. maltophilia. [7] [8]

Mechanical ventilation, or assisted ventilation, is the medical term for artificial ventilation where mechanical means are used to assist or replace spontaneous breathing. This may involve a machine called a ventilator, or the breathing may be assisted manually by a suitably qualified professional, such as an anesthesiologist, respiratory therapist, or paramedic, by compressing a bag valve mask device.

Foley catheter

In urology, a Foley catheter is a flexible tube that a clinician passes through the urethra and into the bladder to drain urine. It is the most common type of indwelling urinary catheter.

Central venous catheter Catheter placed into a large vein

A central venous catheter (CVC), also known as a central line, central venous line, or central venous access catheter, is a catheter placed into a large vein. Catheters can be placed in veins in the neck, chest, groin, or through veins in the arms. It is used to administer medication or fluids that are unable to be taken by mouth or would harm a smaller peripheral vein, obtain blood tests, and measure central venous pressure.

The growth of S. maltophilia in microbiological cultures of respiratory or urinary specimens is difficult to interpret due to its low pathogenicity and not a proof of infection. [2] If, however, it is grown from sites which would be normally sterile (e.g., blood), then it usually represents true infection.

Microbiological culture multiplying microorganisms by letting them reproduce in culture media

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 diagnostic methods used extensively as a research tool in molecular biology.

In immunocompetent individuals, S. maltophilia is a relatively unusual cause of pneumonia, urinary tract infection, or bloodstream infection; in immunocompromised patients, however, S. maltophilia is a growing source of latent pulmonary infections. [9] S. maltophilia colonization rates in individuals with cystic fibrosis have been increasing. [10]

Pneumonia Infection of the lungs

Pneumonia is an inflammatory condition of the lung affecting primarily the small air sacs known as alveoli. Typically symptoms include some combination of productive or dry cough, chest pain, fever, and trouble breathing. Severity is variable.

Urinary tract infection human and animal infection

A urinary tract infection (UTI) is an infection that affects part of the urinary tract. When it affects the lower urinary tract it is known as a bladder infection (cystitis) and when it affects the upper urinary tract it is known as kidney infection (pyelonephritis). Symptoms from a lower urinary tract include pain with urination, frequent urination, and feeling the need to urinate despite having an empty bladder. Symptoms of a kidney infection include fever and flank pain usually in addition to the symptoms of a lower UTI. Rarely the urine may appear bloody. In the very old and the very young, symptoms may be vague or non-specific.

Bacteremia is the presence of bacteria in the blood. Blood is normally a sterile environment, so the detection of bacteria in the blood is always abnormal. It is distinct from sepsis, which is the host response to the bacteria.

Inflammatory responses against bacteria or bacterial products are the main pathogenic mechanisms of S. maltophilia infection. S. maltophilia secretes outer membrane vesicles (OMVs), that cause inflammatory response. OMVs from S. maltophilia ATCC 13637 were found to be cytotoxic to human lung epithelial cells. There OMVs stimulate the expression of proinflammatory cytokine and chemokine genes, including interleukin (IL)-1β, IL-6, IL-8, tumor necrosis factor-α and monocyte chemoattractant protein-1. [11]


S. maltophilia is naturally resistant to many broad-spectrum antibiotics (including all carbapenems) due to the production of two inducible chromosomal metallo-β-lactamases (designated L1 and L2). [12] This makes treatment of infected patients very difficult. S. maltophilia is ubiquitously present in the environment and impossible to eradicate, which makes prevention also extremely difficult.

Sensitivity testing requires nonstandard culture techniques (incubation at 30 °C). [13] [14] Testing at the wrong temperature results in isolates being incorrectly reported as being susceptible when they are, in fact, resistant. Disc diffusion methods should not be used, as they are unreliable, and agar dilution should be used instead. [15] [16]

S. maltophilia is not a virulent organism and removal of the infected prosthesis is frequently sufficient to cure the infection; antibiotics are only required if the prosthesis cannot be removed. Many strains of S. maltophilia are sensitive to co-trimoxazole and ticarcillin, though resistance has been increasing. [17] It is usually susceptible to piperacillin, and ceftazidime. [18] Tigecycline is also an effective drug. Polymyxin B may be effective treatment, at least in vitro, though not without frequent adverse effects.


Stenotrophomonas infections have been associated with high morbidity and mortality in severely immunocompromised and debilitated individuals. Risk factors associated with Stenotrophomonas infection include HIV infection, malignancy, cystic fibrosis, neutropenia, mechanical ventilation, central venous catheters, recent surgery, trauma, prolonged hospitalization, intensive care unit admission and broad-spectrum antibiotic use. [2] [19] [20] [21]


Stenotrophomonas maltophilia has had multiple different names in the past. It was first found in a pleural effusion in 1943 and given the name Bacterium bookeri. It was then renamed to Pseudomonas maltophilia in 1961. It was moved to the genus Xanthomonas in 1983, and most recently to Stenotrophomonas in 1993. [2]

Related Research Articles

Biofilm any group of microorganisms in which cells stick to each other and often also to a surface (adherent cells become embedded within a slimy extracellular matrix that is composed of extracellular polymeric substances)

A biofilm comprises any syntrophic consortium 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 (EPS). The cells within the biofilm produce the EPS components, which are typically a polymeric conglomeration 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".

<i>Pseudomonas</i> genus of bacteria

Pseudomonas is a genus of Gram-negative, Gammaproteobacteria, belonging to the family Pseudomonadaceae and containing 191 validly described species. The members of the genus demonstrate a great deal of metabolic diversity and consequently are able to colonize a wide range of niches. Their ease of culture in vitro and availability of an increasing number of Pseudomonas strain genome sequences has made the genus an excellent focus for scientific research; the best studied species include P. aeruginosa in its role as an opportunistic human pathogen, the plant pathogen P. syringae, the soil bacterium P. putida, and the plant growth-promoting P. fluorescens.

<i>Pseudomonas fluorescens</i> species of bacterium

Pseudomonas fluorescens is a common Gram-negative, rod-shaped bacterium. It belongs to the Pseudomonas genus; 16S rRNA analysis has placed P. fluorescens in the P. fluorescens group within the genus, to which it lends its name.

Colistin chemical compound

Colistin, also known as polymyxin E, is an antibiotic produced by certain strains of the bacteria Paenibacillus polymyxa. Colistin is a mixture of the cyclic polypeptides colistin A and B and belongs to the class of polypeptide antibiotics known as polymyxins. Colistin is effective against most Gram-negative bacilli.

The Xanthomonadales are a bacterial order within the Gammaproteobacteria. They are one of the largest groups of bacterial phytopathogens, harbouring species such as Xanthomonas citri, Xanthomonas euvesicatoria, Xanthomonas oryzae and Xylella fastidiosa. These bacteria affect agriculturally important plants including tomatoes, bananas, citrus plants, rice, and coffee. Many species within the order are also human pathogens. Species within the genus Stenotrophomonas are multidrug resistant opportunistic pathogens that are responsible for nosocomial infections in immunodeficient patients.

<i>Staphylococcus haemolyticus</i> species of bacterium

Staphylococcus haemolyticus is a member of the coagulase-negative staphylococci (CoNS). It is part of the skin flora of humans, and its largest populations are usually found at the axillae, perineum, and inguinal areas. S. haemolyticus also colonizes primates and domestic animals. It is a well-known opportunistic pathogen, and is the second-most frequently isolated CoNS. Infections can be localized or systemic, and are often associated with the insertion of medical devices. The highly antibiotic-resistant phenotype and ability to form biofilms make S. haemolyticus a difficult pathogen to treat.

<i>Pseudomonas aeruginosa</i> common bacterium

Pseudomonas aeruginosa is a common encapsulated, Gram-negative, 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.

Carbapenem group of β-lactam antibiotics

Carbapenems are a class of highly effective antibiotic agents commonly used for the treatment of severe or high-risk bacterial infections. This class of antibiotics is usually reserved for known or suspected multidrug-resistant (MDR) bacterial infections. Similar to penicillins and cephalosporins, carbapenems are members of the beta lactam class of antibiotics, which kill bacteria by binding to penicillin-binding proteins, thus inhibiting bacterial cell wall synthesis. However, these agents individually exhibit a broader spectrum of activity compared to most cephalosporins and penicillins. Furthermore, carbapenems are typically unaffected by emerging antibiotic resistance, even to other beta-lactams.

<i>Staphylococcus epidermidis</i> species of bacterium

Staphylococcus epidermidis is a Gram-positive bacterium, and one of over 40 species belonging to the genus Staphylococcus. It is part of the normal human flora, typically the skin flora, and less commonly the mucosal flora. It is a facultative anaerobic bacteria. Although S. epidermidis is not usually pathogenic, patients with compromised immune systems are at risk of developing infection. These infections are generally hospital-acquired. S. epidermidis is a particular concern for people with catheters or other surgical implants because it is known to form biofilms that grow on these devices. Being part of the normal skin flora, S. epidermidis is a frequent contaminant of specimens sent to the diagnostic laboratory.

<i>Enterococcus faecalis</i> species of bacterium

Enterococcus faecalis – formerly classified as part of the group D Streptococcus system – is a Gram-positive, commensal bacterium inhabiting the gastrointestinal tracts of humans and other mammals. Like other species in the genus Enterococcus, E. faecalis is found in healthy humans, but can cause life-threatening infections, especially in the nosocomial (hospital) environment, where the naturally high levels of antibiotic resistance found in E. faecalis contribute to its pathogenicity. E. faecalis has been frequently found in reinfected, root canal-treated teeth in prevalence values ranging from 30% to 90% of the cases. Re-infected root canal-treated teeth are about nine times more likely to harbor E. faecalis than cases of primary infections.

Bartonellosis is an infectious disease produced by bacteria of the genus Bartonella. Bartonella species cause diseases such as Carrión´s disease, trench fever, cat-scratch disease, bacillary angiomatosis, peliosis hepatis, chronic bacteremia, endocarditis, chronic lymphadenopathy, and neurological disorders.

Sulfamethizole chemical compound

Sulfamethizole is a sulfonamide antibiotic.

<i>Chromobacterium violaceum</i> species of bacterium

Chromobacterium violaceum is a Gram-negative, facultative anaerobic, non-sporing coccobacillus. It is motile with the help of a single flagellum which is located at the pole of the coccobacillus. Usually, there are one or two more lateral flagella as well. It is part of the normal flora of water and soil of tropical and sub-tropical regions of the world. It produces a natural antibiotic called violacein, which may be useful for the treatment of colon and other cancers. It grows readily on nutrient agar, producing distinctive smooth low convex colonies with a dark violet metallic sheen. Some strains of the bacteria which do not produce this pigment have also been reported. It has the ability to break down tarballs.

Stenotrophomonas is a genus of Gram-negative bacteria, comprising at least ten species. The main reservoirs of Stenotrophomonas are soil and plants. Stenotrophomonas species range from common soil organisms to opportunistic human pathogens, the molecular taxonomy of the genus is still somewhat unclear.

Pseudomonas pertucinogena is a Gram-negative, rod-shaped, motile bacterium. It derives its name from the fact that it produces pertucin, a bacteriocin active against phase I organisms of Bordetella pertussis. Based on 16S rRNA analysis, P. pertucinogena has been placed in the P. pertucinogena group, named after this species.

<i>Enterobacter cloacae</i> species of bacterium

Enterobacter cloacae is a clinically significant Gram-negative, facultatively-anaerobic, rod-shaped bacterium.

Sisomicin chemical compound

Sisomicin is an aminoglycoside antibiotic, isolated from the fermentation broth of a new species of the genus Micromonospora. It is a newer broad-spectrum aminoglycoside most structurally related to gentamicin.

<i>Staphylococcus capitis</i> species of 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, and ears and has been associated with prosthetic valve endocarditis, but is rarely associated with native valve infection.

<i>Proteus penneri</i> species of bacterium

Proteus penneri is a Gram-negative, facultatively anaerobic, rod-shaped bacterium. It is an invasive pathogen and a cause of nosocomial infections of the urinary tract or open wounds. Pathogens have been isolated mainly from the urine of patients with abnormalities in the urinary tract, and from stool. P. penneri strains are naturally resistant to numerous antibiotics, including penicillin G, amoxicillin, cephalosporins, oxacillin, and most macrolides, but are naturally sensitive to aminoglycosides, carbapenems, aztreonam, quinolones, sulphamethoxazole, and co-trimoxazole. Isolates of P. penneri have been found to be multiple drug-resistant (MDR) with resistance to six to eight drugs. β-lactamase production has also been identified in some isolates.


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