Pseudomonas stutzeri knee arthritis in a child: case report and review

Monohexosylceramides from Rhizopus Species Isolated from Brazilian Caatinga: Chemical Characterization and Evaluation of Their Anti-Biofilm and Antibacterial Activities

Monohexosylceramides (CMHs) are highly conserved fungal glycosphingolipids playing a role in several cellular processes such as growth, differentiation and morphological transition. In this study, we report the isolation, purification and chemical characterization of CMHs from Rhizopus stolonifer and R. microspores. Using positive ion mode ESI-MS, two major ion species were observed at m/z 750 and m/z 766, respectively. Both ion species consisted of a glucose/galactose residue attached to a ceramide moiety containing 9-methyl-4,8-sphingadienine with an amidic linkage to a hydroxylated C16:0 fatty acid. The antimicrobial activity of CMH was evaluated against Gram positive and Gram negative bacteria using the agar diffusion assay. CMH from both Rhizopus species inhibited the growth of Bacillus terrae, Micrococcus luteus (M. luteus) and Pseudomonas stutzeri (P. stutzeri) with a MIC₅₀ of 6.25, 6.25 and 3.13 mg/mL, respectively. The bactericidal effect was detected only for M. luteus and P. stutzeri, with MBC values of 25 and 6.25 mg/mL, respectively. Furthermore, the action of CMH on the biofilm produced by methicillin-resistant Staphylococcus aureus (MRSA) was analyzed using 12.5 and 25 mg/mL of CMH from R. microsporus. Total biofilm biomass, biofilm matrix and viability of the cells that form the biofilm structure were evaluated. CMH from R. microsporus was able to inhibit the MRSA biofilm formation in all parameters tested.

Infective endocarditis caused by Pseudomonas stutzeri in a patient with Marfan syndrome: Case report and brief literature review

Invasive infections due to Pseudomonas stutzeri have rarely been described and mainly occur in immunocompromised individuals. We report a case of infective endocarditis caused by P. stutzeri after previous cardiac surgery in a Lebanese patient with Marfan syndrome. We review the literature and conclude that this pathogen may be of particular medical relevance in the Mediterranean Basin.

Prevalence of plant beneficial and human pathogenic bacteria isolated from salad vegetables in India

BACKGROUND

The study aimed at enumerating, identifying and categorizing the endophytic cultivable bacterial community in selected salad vegetables (carrot, cucumber, tomato and onion). Vegetable samples were collected from markets of two vegetable hot spot growing areas, during two different crop harvest seasons. Crude and diluted vegetable extracts were plated and the population of endophytic bacteria was assessed based on morphologically distinguishable colonies. The bacterial isolates were identified by growth in selective media, biochemical tests and 16S rRNA gene sequencing.

RESULTS

The endophytic population was found to be comparably higher in cucumber and tomato in both of the sampling locations, whereas lower in carrot and onion. Bacterial isolates belonged to 5 classes covering 46 distinct species belonging to 19 genera. Human opportunistic pathogens were predominant in carrot and onion, whereas plant beneficial bacteria dominated in cucumber and tomato. Out of the 104 isolates, 16.25% are human pathogens and 26.5% are human opportunistic pathogens.

CONCLUSIONS

Existence of a high population of plant beneficial bacteria was found to have suppressed the population of plant and human pathogens. There is a greater potential to study the native endophytic plant beneficial bacteria for developing them as biocontrol agents against human pathogens that are harboured by plants.

[Isolation of Pseudomonas stutzeri from an odontogenic inflammatory cyst: Diagnostic relevance]

Pseudomonas stutzeri is distributed widely in the environment, and occupies different ecological niches. However, it is found in clinically relevant infections as an opportunistic pathogen. Isolation of P. stutzeri from an odontogenic inflammatory cyst is an uncommon microbiological finding that has not been reported to date. In the case presented here, the bacterium was isolated from surgical material obtained from excision of an inflammatory odontogenic cyst located in the tooth 1.2, and presenting with concomitant pulp necrosis. Complementary techniques such as radiographs, CAT scans, and histopathological and microbiological studies were used to establish definitive diagnosis. The obtained results allowed classifying the process as an inflammatory cyst infected by P. stutzeri. Biotyping and characterization of the susceptibility profile of the isolated strain allowed adjusting the antibiotic therapy more specifically. The microbiological studies allowed establishing the etiology of the infectious process, adjusting the treatment plan, and re-establishing tissue integrity.

Prosthetic vascular graft infection and prosthetic joint infection caused by Pseudomonas stutzeri

Pseudomonas stutzeri is infrequently isolated from clinical specimens, and if isolated, more likely represents colonization or contamination rather than infection. Despite this, there are dozens of case reports which describe clinically significant P. stutzeri infections at variable sites. A 69-year-old man had a P. stutzeri infection of a prosthetic vascular graft infection, which he received in Panama City. He was successfully treated with a single antipseudomonal agent for 6 weeks and the removal of the infected vascular graft. A 70-year-old man had a P. stutzeri infection of a prosthetic joint, which was successfully treated with a single anti-pseudomonal agent for 6 weeks. There is only one other documented case of a prosthetic vascular graft infection secondary to P. stutzeri. There are 5 documented cases of P. stutzeri prosthetic joint infections. The previous cases were treated with antibiotics and variably, source control with the removal of prosthetic material. Most cases of P. stutzeri infection are due to exposure in health care settings. Immunocompromised states such as HIV or hematological and solid tumor malignancies are risk factors for P. stutzeri infection. Infections caused by P. stutzeri are far less frequent and less fatal than those caused by P. aeruginosa. The etiology of a P. stutzeri infection could be exposure to soil and water, but also contaminated material in the health care setting or an immunocompromised state. Iatrogenic infections that are secondary to health care tourism are a potential cause of fever in the returned traveler.