Proteus penneri | |
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Electron micrograph of Proteus penneri. Bar represents 200nm. | |
Scientific classification ![]() | |
Domain: | Bacteria |
Phylum: | Pseudomonadota |
Class: | Gammaproteobacteria |
Order: | Enterobacterales |
Family: | Enterobacteriaceae |
Genus: | Proteus |
Species: | P. penneri |
Binomial name | |
Proteus penneri Hickman et al. 1982 | |
Proteus penneri is a Gram-negative, facultatively anaerobic, rod-shaped bacterium. [1] It is an invasive pathogen [2] and a cause of nosocomial infections of the urinary tract or open wounds. [3] Pathogens have been isolated mainly from the urine of patients with abnormalities in the urinary tract, and from stool. [4] 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. [5]
The Proteus penneri group of bacteria was named in 1982. It reclassified a group of strains formerly known as Proteus vulgaris biogroup 1. [6] In 1978, Brenner et al. showed through DNA hybridization studies that P. vulgaris was a heterogenous species. [7] In 1981, Hickman et al conducted experiments on 20 indole-negative strains previously grouped with P.vulgaris and demonstrated the existence of three P. vulgaris biogroups. P. vulgaris biogroup 1, or indole-negative P. vulgaris, was distinguished as a new species within the genus Proteus in 1982. [1] The new species was named Proteus penneri in honor of John Penner, a Canadian microbiologist. [4]
Extended biochemical tests have characterized P. penneri as being uniformly salicin negative. The inability to produce ornithine decarboxylase differentiates P. penneri from another indole-negative Proteus species, P.mirabilis . [2] P. penneri isolates are not fermenters of salicin and not users of citrate, but acidify sucrose and maltose. [5] Other chief characteristics of this species that enable its differentiation from other Proteus species include failure to acidify esculin, failure to produce hydrogen sulfide on triple sugar iron agar, and resistance to chloramphenicol. [8] The resistance of P. penneri to cefuroxime and the marked inhibitory activity of cefoxitin against this species also distinguishes P. penneri from the other Proteus. [9] Similar to other Proteus species, P. penneri has a cell-bound hemolytic factor, which has been shown to facilitate penetration of the organism into cultured Vero cells without any cytotoxic effects. It also has a filterable cytotoxic alpha-hemolysin rarely found in other Proteus species. [7] A highly active urease produced by P. penneri may also have a role in the establishment of an infectious process. [8]
The application of molecular techniques such as the polymerase chain reaction to produce DNA fingerprints and other 16S ribosomal RNA gene (ribotyping) methods of strain analysis have been employed to differentiate P. penneri from P. vulgaris and P. mirabilis strains. The RAPD technique, fundamentally a DNA fingerprinting method, has exposed a substantial DNA diversity among P. penneri strains, a characteristic that remained unidentified by other methods. [10]
Test | Result |
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Microscopic morphology | Gram-negative rods |
Hemolysis (sheep blood agar) | Beta |
Urease | Positive |
Indole production | Negative |
Esculin hydrolysis | Negative |
Acid from Maltose | Positive |
Acid from Sucrose | Positive |
Citrate use | Negative |
Ornithine decarboxylase | Negative |
Hydrogen sulfide production | Positive |
The lipopolysaccharide (LPS) core region of P. penneri strains contains higher structural variability than that observed in other representatives of Enterobacterales. [11] These differences have been used to cluster P. penneri strains into serogroups based on their agglutinating activity when mixed with antibodies directed against specific species of LPS molecules. [12] Presently, 15 O-serogroups have been proposed for P. penneri based on the chemical structure of the O-specific polysaccharide chain (O-antigen) of the lipopolysaccharide. [13] [14] [15] Certain LPS epitopes have been examined to determine their function in antigenic specificity. The particular groups on the oligosaccharides found to play a dominant role in the specificity of P. penneri LPS are the amide of D-galacturonic acid with L-lysine α-D-GalA-(L-Lys) (and the amide of D-galacturonic acid with L-threonine α-D-GalA- [L-Thr]), respectively. [12]
The occurrence of P. penneri organisms in the normal intestine accounts for their higher frequency in urinary tract infections and for their role as opportunistic invaders after surgery. [16] P. penneri is absent from the intestines of livestock. [10] The optimum growth condition for P. penneri is achieved at 37 °C, which mirrors the intestinal niche colonized by many of these bacteria. Certain strains of P. penneri can differentiate into elongated hyperflagelled cells during development on solid media, resulting in the surface translocation event identified as “swarming”. Swarming motility makes it difficult to isolate single colonies for further study. [17]
The proportion of P. penneri strains isolated in clinical specimens is unknown. [9] Since P. penneri was only recently recognized as a new species, many bacteriologists are either generally unaware of it, or have made limited attempts to discover its clinical significance. Thus, reports on the isolation of P. penneri from infected patients is limited. [2] Although increasing numbers of laboratories are now identifying P.penneri strains, the numbers reported in susceptibility studies are relatively small for a general assessment of the incidence of the species. [9] Likewise, the epidemiology of P.penneri is also unknown for these reasons.
Documented human clinical infections caused by P. penneri have been limited to the urinary tract and to wounds of the abdomen, groin, neck, and ankle. [8] This species is isolated from individuals in long-term care facilities and hospitals and from patients who are immunocompromised or suffering from underlying disease. P. penneri was isolated significantly more often from stools of patients with diarrheal disease than from healthy patients, so P. penneri may play a role in some diarrheal disease. [18] The invasive potential of this microorganism has also been demonstrated in a case of P. penneri bacteremia and concomitant subcutaneous thigh abscess in a neutropenic patient with acute lymphocytic leukemia [8] and in nosocomial urosepsis in a diabetic patient from whom the organism was also subsequently isolated from bronchoalveolar lavage fluid and a pulmonary catheter tip. [19] Furthermore, in an experiment conducted in India, P. penneri strains were isolated as the sole pathogen in all patients having underlying disease postoperatively. Most isolates of P. penneri from the experiment were found to be multiple drug-resistant including resistance to amoxy-clavulanic acid combination. [2] In another study, P. penneri was found to be more resistant to the penicillins and cephalosporins than P. mirabilis and mostly in patients with urogenital infections. [5] Moreover, the urease enzyme of P. penneri is thought to be a significant cause of kidney stone formation. Consistent with this belief, the organism has been isolated from the center of a stone removed from a patient with persistent P. penneri bacteriuria. [20] These data substantiate the need for species-level identification of P. penneri in the clinical setting.
Several virulence factors of P. penneri can make infections from this invasive pathogen more pronounced, persistent, and harder to eradicate. [2] These include adherence due to the presence of fimbriae or afimbrial adhesins, invasiveness, swarming phenomenon, hemolytic activity, urea hydrolysis, proteolysis, and endotoxicity. [21] Swarming motility is the coordinated translocation of a bacterial population driven by flagellar rotation in film or on fluid surfaces. [22] An emerging concept in microbiology, the fundamental role of swarming motility remains unknown. However, it has been observed to be correlated with an elevated resistance to certain antibiotics. [23] Production of IgA proteolytic enzymes has also been reported in P. penneri. [24] Secretory immunoglobulins of the IgA class are produced by mucous tissue and are particularly resistant to enzymatic breakdown by proteases. The ability to degrade a host’s secretory IgA may provide P. penneri with an advantage by permitting it to evade the host immune response, therefore gaining valuable time for the bacterium to establish a foothold for infection. However, the major mechanism of antimicrobial resistance is caused by hyperproduction of the chromosomally encoded β-lactamase, sometimes by plasmids. These inducible β-lactamases hydrolyze primary and extended-spectrum penicillins and cephalosporins, [25] thus making P. penneri strains naturally resistant to penicillin G, amoxicillin, cephalosporins (i.e. cefaclor, cefazoline, cefuroxime, and cefdinir), oxacillin, and most macrolides. [2]
Most isolated P. penneri strains are multiple-drug resistant, with 12 being the highest drug-resistance number reported. [2] P. penneri has a distinguishing susceptibility profile, based on the production of the chromosomally induced β-lactamase HugA. HugA determines resistance to aminopenicillins and first- and second-generation cephalosporins, including cefuroxime. However, HugA does not affect cephamycins or carbapenems and is inhibited by clavulanic acid. Similar to other Proteus species, P. penneri is resistant to tetracyclines and nitrofurantoin. [26]
Presently, all tested strains of P. penneri have been found to be highly susceptible to: [27]
Most strains with a few exceptions are also susceptible to:
All tested strains have been found resistant to:
Information on the treatment of P. penneri infections is limited, but the use of gentamicin, tobramycin, netilmicin, and amikacin have been indicated as possible drugs of choice for the treatment of systemic infections caused by susceptible P. penneri strains. In vitro studies of ceftizoxime, ceftazidime, moxalactam, and cefoxitin suggest these agents also may prove to be clinically useful in treating infections caused by P. penneri. [27]
Proteus vulgaris is a rod-shaped, nitrate-reducing, indole-positive and catalase-positive, hydrogen sulfide-producing, Gram-negative bacterium that inhabits the intestinal tracts of humans and animals. It can be found in soil, water, and fecal matter. It is grouped with the Morganellaceae and is an opportunistic pathogen of humans. It is known to cause wound infections and other species of its genera are known to cause urinary tract infections.
Proteus is a genus of Gram-negative bacteria. It is a rod shaped, aerobic and motile bacteria, which is able to migrate across surfaces due its “swarming” characteristic in temperatures between 20 and 37 °C. Their size generally ranges from 0.4 to 0.8 μm in diameter and 1.0–3.0 μm in length. They tend to have an ammonia smell. Proteus bacilli are widely distributed in nature as saprophytes, being found in decomposing animal matter, sewage, manure soil, the mammalian intestine, and human and animal feces. They are opportunistic pathogens, commonly responsible for urinary and septic infections, often nosocomial.
The cephalosporins are a class of β-lactam antibiotics originally derived from the fungus Acremonium, which was previously known as Cephalosporium.
Cefazolin, also known as cefazoline and cephazolin, is a first-generation cephalosporin antibiotic used for the treatment of a number of bacterial infections. Specifically it is used to treat cellulitis, urinary tract infections, pneumonia, endocarditis, joint infection, and biliary tract infections. It is also used to prevent group B streptococcal disease around the time of delivery and before surgery. It is typically given by injection into a muscle or vein.
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.
Escherichia is a genus of Gram-negative, non-spore-forming, facultatively anaerobic, rod-shaped bacteria from the family Enterobacteriaceae. In those species which are inhabitants of the gastrointestinal tracts of warm-blooded animals, Escherichia species provide a portion of the microbially derived vitamin K for their host. A number of the species of Escherichia are pathogenic. The genus is named after Theodor Escherich, the discoverer of Escherichia coli. Escherichia are facultative aerobes, with both aerobic and anaerobic growth, and an optimum temperature of 37 °C. Escherichia are usually motile by flagella, produce gas from fermentable carbohydrates, and do not decarboxylate lysine or hydrolyze arginine. Species include E. albertii, E. fergusonii, E. hermannii, E. ruysiae, E. marmotae and most notably, the model organism and clinically relevant E. coli. Formerly, Shimwellia blattae and Pseudescherichia vulneris were also classified in this genus.
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. Its most closely related species is Staphylococcus borealis.
Loracarbef is an antibiotic. It is a carbacephem, but it is sometimes grouped together with the second-generation cephalosporin antibiotics. Loracarbef is a synthetic "carba" analog of cefaclor, and is more stable.
Carbapenems are a class of very effective antibiotic agents most commonly used for treatment of severe 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 antibiotics drug class, 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.
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 characteristic striking 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.
Mecillinam (INN) or amdinocillin (USAN) is an extended-spectrum penicillin antibiotic of the amidinopenicillin class that binds specifically to penicillin binding protein 2 (PBP2), and is only considered to be active against Gram-negative bacteria. It is used primarily in the treatment of urinary tract infections, and has also been used to treat typhoid and paratyphoid fever. Because mecillinam has very low oral bioavailability, an orally active prodrug was developed: pivmecillinam.
Morganella morganii is a species of Gram-negative bacteria. It has a commensal relationship within the intestinal tracts of humans, mammals, and reptiles as normal flora. Although M. morganii has a wide distribution, it is considered an uncommon cause of community-acquired infection, and it is most often encountered in postoperative and other nosocomial infections, such as urinary tract infections.
L-form bacteria, also known as L-phase bacteria, L-phase variants or cell wall-deficient bacteria (CWDB), are growth forms derived from different bacteria. They lack cell walls. Two types of L-forms are distinguished: unstable L-forms, spheroplasts that are capable of dividing, but can revert to the original morphology, and stable L-forms, L-forms that are unable to revert to the original bacteria.
Ewingella americana is a Gram-negative rod, and the only species in the genus Ewingella. It was first identified and characterized in 1983. Ewingella is in the family Yersiniaceae. The organism is rarely reported as a human pathogen, though it has been isolated from a variety of clinical specimens, including wounds, sputum, urine, stool, blood, synovial fluid, conjunctiva, and peritoneal dialysate. The bacterium is named in honor of William H. Ewing, an American biologist who contributed to modern taxonomy.
Pseudescherichia vulneris is a Gram-negative bacterial species. P. vulneris is a fermentative, oxidase-negative, motile rod, which holds characteristics of the family Enterobacteraceae. This bacterium can colonize in the respiratory tract, genital tract, stool, and urinary tract. However, P. vulneris is most often associated with wounds and has been known to colonize open wounds of both humans and animals. This association gave the bacterium its species name, vulneris, which is Latin for wound. It has also been infrequently reported in cases of meningitis. It was identified as Escherichia vulneris in 1982 with a 2017 genomic analysis of its original genus resulting in the creation of its new genus Pseudescherichia.
Legionella anisa is a Gram-negative bacterium, one of more than 40 species in the family Legionellaceae. After Legionella pneumophila, this species has been isolated most frequently from water samples. This species is also one of the several pathogenic forms of Legionella having been associated with rare clinical cases of illness including Pontiac fever and Legionnaires' disease.
Enterobacter taylorae is a Gram-negative bacteria formerly known as Enteric Group 19, and also known as Enterobacter cancerogenus. Strains of E. taylorae are positive for: Voges-Proskauer, citrate utilization, arginine dihydrolase and malonate utilization. They ferment D-glucose and also ferment D-mannitol, L-rhamnose and cellobiose. They are negative for indole production, urea hydrolysis, lysine decarboxylase and fermentation of adonitol, D-sorbitol and raffinose. It occurs in human clinical specimens, being isolated from blood and from spinal fluid. It is known to cause infections and is not susceptible to penicillins nor cephalosporins.
Kluyvera ascorbata is a bacterium, the type species of its genus. It is Gram-negative, rod-shaped and motile with peritrichous flagella.
Ceftolozane/tazobactam, sold under the brand name Zerbaxa, is a fixed-dose combination antibiotic medication used for the treatment of complicated urinary tract infections and complicated intra-abdominal infections in adults. Ceftolozane is a cephalosporin antibiotic, developed for the treatment of infections with gram-negative bacteria that are resistant to conventional antibiotics. It was studied for urinary tract infections, intra-abdominal infections and ventilator-associated bacterial pneumonia.
The Morganellaceae are a family of Gram-negative bacteria that include some important human pathogens formerly classified as Enterobacteriaceae. This family is a member of the order Enterobacterales in the class Gammaproteobacteria of the phylum Pseudomonadota. Genera in this family include the type genus Morganella, along with Arsenophonus, Cosenzaea, Moellerella, Photorhabdus, Proteus, Providencia and Xenorhabdus.
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