Pantoea agglomerans and thorn-associated suppurative arthritis

Bloodstream Infections by Pantoea Species: Clinical and Microbiological Findings from a Retrospective Study, Italy, 2018-2023

(1) Background: The widespread use of MALDI-TOF coupled to mass spectrometry has improved diagnostic accuracy by identifying uncommon bacteria. Among Enterobacterales, Pantoea species have been seen to be implicated in several human infections, but their clinical and microbiological framework is currently based on a few anecdotal reports. (2) Methods: We conducted this five-year (2018-2023) single-center study aimed at investigating the prevalence and clinical and microbiological findings of Pantoea species bloodstream infections. (3) Results: Among the 4996 bloodstream infection Gram-negative isolates collected during the study period, Pantoea species accounted for 0.4% (n = 19) of isolates from 19 different patients, 5 of them being pediatric cases. Among Pantoea species isolates, P. agglomerans was the most frequently detected (45%; n = 9) followed by P. eucrina (30%; n = 6) and P. septica (15%; n = 3). Malignancy (35.7%) in adults and malignancy (40%) and cerebrovascular disease following meconium aspiration (40%) in pediatric patients as comorbidities and shivering and/or fever following parenteral infusion (36.8%) as a symptom/sign of Pantoea species bloodstream infection onset were the most frequently observed clinical features. Among adults, primary bloodstream infection was the most frequent (50%), whereas among pediatric patients, the most commonly identified sources of infection were catheter-related (40%) and the respiratory tract (40%). Overall, Pantoea species bloodstream infection isolates displayed high susceptibility to all the antibiotics except for ampicillin (63.2%), fosfomycin (73.7%), and piperacillin/tazobactam (84.2%). Targeted antibiotic treatment was prescribed as monotherapy for adults (71.4%) and combination therapy for pediatric patients (60%). The most prescribed antibiotic regimens were piperacillin/tazobactam (21.4%) in adults and meropenem- (40%) and aminoglycoside-containing (40%) antibiotics in pediatric patients. The overall 28-day all-cause mortality rate was 5.3% (n = 1). (4) Conclusions: The prevalence and 28-day mortality rate of Pantoea species bloodstream infections were low. The prescription of targeted therapy including broad-spectrum antibiotics could indicate an underestimation of the specific involvement of the Pantoea species in the onset of the disease, warranting further studies defining their pathogenic potential.

Pantoea abscess mimicking sarcoma in a HTLV-1-infected Indigenous Australian man: Case report and literature review

Gram-negative bacteria of the genus Pantoea are emerging bacterial causes of diverse sporadic and outbreak-linked infections. Chronic Pantoea abscesses are unusual and may give rise to a differential diagnosis of malignancy. Foreign body retention and host immune defects may be risk factors for such chronic infections.

A Case of Nosocomial Outbreak of Pantoea agglomerans Related to Parenteral Nutrition Procedures

Pantoea agglomerans is a Gram-negative bacterium that infrequently infects humans. Most reports involving it are about infections in soft tissues or bone/joint infections caused by contamination from soil or penetrating trauma by vegetation, such as thorns and splinters. More frequently, it is found as an opportunistic pathogen in immunocompromised patients. It is not rare to find reports of bacteremia and sepsis from contamination of intravenous fluid, parenteral nutrition, blood products and anesthetic agents-that is, through contamination of medical devices and products. We reported a bacterial infection epidemic occurred in 2011 in a hospital in middle Italy which involved different hospital wards; Pantoea agglomerans was isolated from blood cultures of all infected patients and the source of infection was identified in contaminated parenteral nutrition prepared from the local pharmacy.

Septic arthritis of the knee due to Pantoea agglomerans: look for the thorn

We report on a patient with septic arthritis of the knee with Pantoea agglomerans after a penetrating black locust thorn injury. Antibiotics alone or in combination with an arthroscopy may be insufficient for achieving source control. Accurate medical history and open debridement with a search for a thorn fragment are key to successful treatment.

Lipopolysaccharide of Pantoea agglomerans 7460: O-specific polysaccharide and lipid A structures and biological activity

Lipopolysaccharide (LPS) was isolated from Pantoea agglomerans 7460 cells by phenol-water extraction. Mild acid degradation allowed to separate OPS and lipid A. Lipid A was analyzed by negative-ion mode ESI MS and found to consist mainly of hexaacylated derivative containing biphosphorylated GlcN disaccharide, four 14:0 (3-OH), 18:0 and 12:0 fatty acids. The structure of the O-specific polysaccharide was established by chemical, NMR and computational methods: The LPS of Р. agglomerans 7460 showed low level of toxicity and pyrogenicity to compare with LPS of E. coli O55:B5 and pyrogenal, respectively. The ability of the modified (succinylated) LPS, which have lost its toxicity, to block the toxic effects of native LPS has been shown.

Pantoea agglomerans as a Cause of Foreign Body Related Septic Arthritis in a Child: Case Report and Review of the Literature

A previously healthy 7-year-old female patient was admitted with pain and swelling in her left knee and fever. She had injured her left knee 2 weeks ago. Her mother had noticed a protrusion on her knee that she had thought to be associated with a fracture. After being examined by an orthopaedist, fracture was ruled out and the protrusion disappeared. On her admission with fever and painful swollen knee, Pantoea agglomerans was identified in the synovial fluid. On the basis of the close association of P. agglomerans infections with penetrating trauma, the patient and her mother were asked about a history of penetration during the fall, but they denied any possible penetration of a vegetative element since she had fallen on a concrete floor. Although she was treated with antibiotics reported to be sensitive in the antibiogram, she had recurrent septic arthritis. Repeated magnetic resonance imaging (MRI) interpretations revealed a foreign body in the medial aspect of the left knee. The patient underwent arthrotomy and a plant thorn was removed. The postoperative course was uneventful. We reported this case to emphasize that a vegetative foreign body should be kept in mind in septic arthritis caused by P. agglomerans and/or in those resistant to antibiotics. In addition, we reviewed the literature including children having joint and/or bone infections caused by P. agglomerans.

MALDI-TOF MS Detection of Endophytic Bacteria Associated with Great Nettle (Urtica dioica L.), Grown in Algeria

Any plant with a vascular system has a specific endophytic microflora. The identification of bacteria is essential in plant pathology. Although identification methods are effective, they are costly and time consuming. The purpose of this work is to isolate and to identify the different bacteria from the internal tissues of Urtica dioica L. and to study their diversity. This last is based on the different parts of the plant (stems, leaves and roots) and the harvest regions (Dellys and Tlamcen). The identification of bacteria is done by biochemical tests and confirmed by MALDI-TOF MS. Seven genus and eleven species were isolated from the Great Nettle. They belong to the genera Bacillus, Escherichia, Pantoea, Enterobacter, Staphylococcus, Enterococcus and Paenibacillus. The majority of these bacteria were isolated from Tlemcen which makes this region the richest in endophytic bacteria compared to that harvested from Dellys. The results show also that the leaves are the most diversified in endophytic bacteria. Bacillus pumilus-ME is the common species of the three parts of the plant harvested in both regions. From this work, it emerges that the Great Nettle can be settled by various endophytic bacteria which are differently distributed within the same plant harvested in different regions.

Culture-Proven Thorn-Associated Infections in Arizona: 10-Year Experience at Mayo Clinic

Background

Thorn injuries are common in the desert Southwest; however, the frequency and microbiology of thorn-associated infections have not been systematically described. Most information comes from case reports describing infections from atypical or environmental microorganisms. Our aim was to summarize the spectrum of thorn-associated infections.

Methods

We conducted a retrospective review of electronic health records for patients presenting to our institution from January 1, 2005 to December 31, 2014 for treatment of thorn-associated injuries and then focused on the patients with cultures.

Results

Of 2758 records reviewed, 1327 patients had thorn-associated injuries; however, only 58 (4.4%) had cultures. Of these patients, 37 (64%) had positive findings; 5 had polymicrobial infection. The most commonly identified organisms were Staphylococcus aureus (n = 22, 59.0%) and coagulase-negative Staphylococcus species (n = 8, 21.6%). Other pathogens included Nocardia species (n = 3, 8.1%), Streptococcus species (n = 2, 5.4%), Gram-negative bacteria (n = 2, 5.4%), Aspergillus species (n = 2, 5.4%), Paecilomyces lilacinus (n = 1, 2.7%), and Candida species (n = 1, 2.7%). There were no infections caused by Pantoea agglomerans, Sporothrix schenckii, or Coccidioides spp.

Conclusions

In contrast to most published case reports, we found that typical cutaneous microorganisms, such as Staphylococcus species, caused the majority of culture-positive, thorn-related infections.

Endophthalmitis caused by Pantoea agglomerans: clinical features, antibiotic sensitivities, and outcomes

Purpose

To report the clinical findings, antibiotic sensitivities, and visual outcomes associated with endophthalmitis caused by Pantoea agglomerans.

Methods

A consecutive case series of patients with vitreous culture-positive endophthalmitis caused by P. agglomerans from January 1, 1990 to December 31, 2012 at a large university referral center. Findings from the current study were compared to prior published studies.

Results

Of the three study patients that were identified, clinical settings included trauma (n=2) and post-cataract surgery (n=1). Presenting visual acuity was hand motion or worse in all three cases. All isolates were sensitive to ceftazidime, gentamicin, imipenem, and fluoroquinolones. All isolates were resistant to ampicillin. Initial treatment strategies were vitreous tap and intravitreal antibiotic injection (n=1) and pars plana vitrectomy with intravitreal antibiotic injection (n=2). At last follow-up, one patient had no light perception vision, while the other two had best-corrected visual acuity of 20/200 and 20/400.

Conclusion

All Pantoea isolates were sensitive to ceftazidime, gentamicin, imipenem, and fluoroquinolones. All patients in the current study received at least one intravitreal antibiotic to which P. agglomerans was shown to be sensitive in vitro. In spite of this, the visual outcomes were generally poor.

Quantitative evaluation of the host-colonizing capabilities of the enteric bacterium Pantoea using plant and insect hosts

The genus Pantoea is a highly diverse group comprising free-living, and both pathogenic and non-pathogenic host-associating species. Pathogenic isolates have been found to infect insects, plants and humans, yet it is unclear whether these isolates have similar pathogenic potential to the free-living environmental populations. Using MLSA of six housekeeping genes, we evaluated the phylogenetic relationships among 115 environmental and clinical (human) isolates representing 11 Pantoea species. An overlay of the location of isolation onto the resulting tree revealed that clinical and environmental isolates are interspersed, and do not form distinctive groups. We then conducted quantitative growth assays of our isolates using maize, onion and fruit flies as hosts. Notably, most clinical isolates were able to grow in both plant hosts often comparably or even better than the environmental isolates. There were no obvious growth or host colonization patterns that could distinguish those isolates with clinical potential. Growth of an isolate in one host could not be predicted based on its performance in another host, nor could host growth be predicted by phylogeny or source of isolation. This work demonstrates that the host-colonizing capabilities of all Pantoea species groups is unpredictable, indicating a broader host range and pathogenic potential than currently assumed.

Bacteremia caused by Pantoea agglomerans at a medical center in Taiwan, 2000-2010

BACKGROUND/PURPOSE

There are only three case reports of adult patients with spontaneous Pantoea agglomerans bacteremia in the English literature. The aim of this study was to investigate clinical and microbiologic characteristics patients of P agglomerans bacteremia.

METHODS

We studied all adult patients with P agglomerans bacteremia at a medical center from 2000 to 2010. The isolates were identified using two commercial identification systems.

RESULTS

Of the 18 patients identified, 72% (n = 13) had active gastroesophageal disease treated with antacids. Two-thirds of patients had indwelling central lines and advanced cancers. None of the removed catheter tips yielded P agglomerans and line persistence was not associated with adverse outcomes. Initial disease severity was low, hypotension was uncommon and no patient died of bacteremia. Recurrence of bacteremia occurred in one patient with deep-seated infection. 16srRNA gene sequencing identified only half of the isolates as P agglomerans. The remaining nine isolates were Enterobacter species for six, Pantoea ananatis for two, and Exiguobacterium profundum for one. There were no significant differences between the characteristics of the subgroup molecularly identified as P agglomernas and the overall group characteristics. Eleven (61%) of the 18 isolates were susceptible to cefazolin, six (33%) susceptible to fosfomycin (MIC ≤ 64 mg/ml). Two isolates had colistin MICs ≥ 4 mg/ml.

CONCLUSION

Bacteremia caused by P agglomerans is associated with gastroesophageal reflux disease and receipt of antacids. 16srRNA gene sequencing should not be used as the sole basis for its identification and we have highlighted the need for another molecular-based technique to conclusively characterize P agglomerans.

Acute dacryocystitis in a 2-year old child caused by pantoea

A previously healthy 23-month-old girl was admitted for the management of an acute unilateral dacryocystitis following accidental contact with dog faeces. No periocular trauma was reported. Microbiological investigation showed a multiresistant strain of Pantoea species to be the responsible pathogen. The infection responded to a course of oral Clindamycin and Ciprofloxacin, in combination with Chloramphenicol eye drops. This is the first report of an acute dacryocystitis sustained by this microorganism.

Septic arthritis due to Cellulosimicrobium cellulans

Cellulosimicrobium cellulans has been reported as a rare cause of human pathogenesis. Infections mainly occur in immunocompromised patients and very often are associated with a foreign body. We report the first case of septic arthritis caused by C. cellulans in an immunocompetent patient. Our patient suffered a penetrating palm tree thorn injury to his left knee 8 weeks before admission. Although no foreign objects were found, they were suspected because previous reports suggest a frequent association with this microorganism, and open debridament was performed. Removal of foreign bodies related to this organism must be considered a high-priority treatment in these patients to achieve a complete recovery.

Bacteriophages LIMElight and LIMEzero of Pantoea agglomerans, belonging to the "phiKMV-like viruses"

Pantoea agglomerans is a common soil bacterium used in the biocontrol of fungi and bacteria but is also an opportunistic human pathogen. It has been described extensively in this context, but knowledge of bacteriophages infecting this species is limited. Bacteriophages LIMEzero and LIMElight of P. agglomerans are lytic phages, isolated from soil samples, belonging to the Podoviridae and are the first Pantoea phages of this family to be described. The double-stranded DNA (dsDNA) genomes (43,032 bp and 44,546 bp, respectively) encode 57 and 55 open reading frames (ORFs). Based on the presence of an RNA polymerase in their genomes and their overall genome architecture, these phages should be classified in the subfamily of the Autographivirinae, within the genus of the "phiKMV-like viruses." Phylogenetic analysis of all the sequenced members of the Autographivirinae supports the classification of phages LIMElight and LIMEzero as members of the "phiKMV-like viruses" and corroborates the subdivision into the different genera. These data expand the knowledge of Pantoea phages and illustrate the wide host diversity of phages within the "phiKMV-like viruses."

Biological Warfare of the Spiny Plant Introducing Pathogenic Microorganisms into Herbivore's Tissues

Recently, it has been proposed that plants which have spines, thorns, and prickles use pathogenic aerobic and anaerobic bacteria, as well as pathogenic fungi, for defense against herbivores, especially vertebrates. Their sharp defensive appendages may inject various pathogenic agents into the body of the herbivores by piercing the outer defensive layer of the skin in a type of biological warfare. Here, we review data regarding the various bacterial taxa found on spines, as well as the medical literature regarding infections by bacteria and fungi related to spine injuries. We also present new evidence that, concerning the microbial flora, spines belonging to the palm tree Washingtonia filifera are probably a different habitat than the nondefensive green photosynthetic leaf surfaces. In addition, many plant species have microscopic internal and external spines (raphids and silica needles) which can also wound large herbivores as well as insects and other small invertebrate herbivores that usually attack in between large spines, prickles, and thorns. The large spines and sharp microscopic structures may inject not only the microorganisms that inhabit them into the herbivore's tissues, but also those preexisting on the skin surface or inside the digestive system of the herbivores and on the surface of nonspiny plant parts. A majority of the spiny plants visually advertise their spiny nature, a characteristic known as aposematism (warning coloration). The pathogenic microorganisms may sometimes be much more dangerous than the physical wounds inflicted by the spines. In accordance, we suggest that the possible cooperation or even just the random association of spines with pathogenic microorganisms contributed to the evolution of aposematism in spiny plants and animals. The role of these sharp defensive structures in inserting pathogenic viruses into the tissues of herbivores was never studied systematically and deserves special attention.

Structure of the D-alanylgriseoluteic acid biosynthetic protein EhpF, an atypical member of the ANL superfamily of adenylating enzymes

The structure of EhpF, a 41 kDa protein that functions in the biosynthetic pathway leading to the broad-spectrum antimicrobial compound D-alanylgriseoluteic acid (AGA), is reported. A cluster of approximately 16 genes, including ehpF, located on a 200 kbp plasmid native to certain strains of Pantoea agglomerans encodes the proteins that are required for the conversion of chorismic acid to AGA. Phenazine-1,6-dicarboxylate has been identified as an intermediate in AGA biosynthesis and deletion of ehpF results in accumulation of this compound in vivo. The crystallographic data presented here reveal that EhpF is an atypical member of the acyl-CoA synthase or ANL superfamily of adenylating enzymes. These enzymes typically catalyze two-step reactions involving adenylation of a carboxylate substrate followed by transfer of the substrate from AMP to coenzyme A or another phosphopantetheine. EhpF is distinguished by the absence of the C-terminal domain that is characteristic of enzymes from this family and is involved in phosphopantetheine binding and in the second half of the canonical two-step reaction that is typically observed. Based on the structure of EhpF and a bioinformatic analysis, it is proposed that EhpF and EhpG convert phenazine-1,6-dicarboxylate to 6-formylphenazine-1-carboxylate via an adenylyl intermediate.

Case report: subacute synovitis of the knee after a rose thorn injury: unusual clinical picture

Synovitis secondary to penetrating plant thorn injuries is not frequently reported. Historically, it is considered aseptic and treated with removal of the intraarticular foreign body and affected synovial lining. We report a 57-year-old healthy man who was admitted 2 weeks after being injured by a rose (Rosacea) thorn with subacute and mild synovitis with effusion of his right knee. No intraarticular foreign body was retained. Pantoea agglomerans was identified in the synovial fluid. Contrary to former teaching, effusions from joints violated by thorns should not be presumed sterile. Bacterial growth is reported infrequently, but when reported, Pantoea agglomerans is the most common organism found. We recommend removal of foreign bodies if present, arthroscopic total synovectomy, and beginning empiric antibiotic treatment with coverage against gram-negative enteric pathogens in all cases of thorn synovitis until the results of culture specimens are known. Improved physician awareness can result in more rapid diagnosis and improved clinical outcome in affected individuals.

Pantoea agglomerans, a plant pathogen causing human disease

We present 53 pediatric cases of Pantoea agglomerans infections cultured from normally sterile sites in patients seen at a children's hospital over 6 years. Isolates included 23 from the bloodstream, 14 from abscesses, 10 from joints/bones, 4 from the urinary tract, and 1 each from the peritoneum and the thorax. P. agglomerans was most associated with penetrating trauma by vegetative material and catheter-related bacteremia.

Comparative opsonic and protective activities of Staphylococcus aureus conjugate vaccines containing native or deacetylated Staphylococcal Poly-N-acetyl-beta-(1-6)-glucosamine

Staphylococcus aureus and Staphylococcus epidermidis both synthesize the surface polysaccharide poly-N-acetyl-beta-(1-6)-glucosamine (PNAG), which is produced in vitro with a high level (>90%) of the amino groups substituted by acetate. Here, we examined the role of the acetate substituents of PNAG in generating opsonic and protective antibodies. PNAG and a deacetylated form of the antigen (dPNAG; 15% acetylation) were conjugated to the carrier protein diphtheria toxoid (DT) and used to immunize animals. Mice responded in a dose-dependent fashion to both conjugate vaccines, with maximum antibody titers observed at the highest dose and 4 weeks after the last of three weekly immunizations. PNAG-DT and dPNAG-DT vaccines were also very immunogenic in rabbits. Antibodies raised to the conjugate vaccines in rabbits mediated the opsonic killing of various staphylococcal strains, but the specificity of the opsonic killing was primarily to dPNAG, as this antigen inhibited the killing of S. aureus strains by both PNAG- and dPNAG-specific antibodies. Passive immunization of mice with anti-dPNAG-DT rabbit sera showed significant levels of clearance of S. aureus from the blood (54 to 91%) compared to control mice immunized with normal rabbit sera, whereas PNAG-specific antibodies were ineffective at clearing S. aureus. Passive immunization of mice with a goat antiserum raised to the dPNAG-DT vaccine protected against a lethal dose of three different S. aureus strains. Overall, these data show that immunization of animals with a conjugate vaccine of dPNAG elicit antibodies that mediated opsonic killing and protected against S. aureus infection, including capsular polysaccharide types 5 and 8 and an untypable strain.

Bioinformatics, genomics and evolution of non-flagellar type-III secretion systems: a Darwinian perpective

We review the biology of non-flagellar type-III secretion systems from a Darwinian perspective, highlighting the themes of evolution, conservation, variation and decay. The presence of these systems in environmental organisms such as Myxococcus, Desulfovibrio and Verrucomicrobium hints at roles beyond virulence. We review newly discovered sequence homologies (e.g., YopN/TyeA and SepL). We discuss synapomorphies that might be useful in formulating a taxonomy of type-III secretion. The problem of information overload is likely to be ameliorated by launch of a web site devoted to the comparative biology of type-III secretion ().