Gram-negative Facultative Anaerobe Research Articles

Tad pili contribute to the virulence and biofilm formation of virulent Aeromonas hydrophila

Type IV pili (T4P) are versatile proteinaceous protrusions that mediate diverse bacterial processes, including adhesion, motility, and biofilm formation. Aeromonas hydrophila, a Gram-negative facultative anaerobe, causes disease in a wide range of hosts. Previously, we reported the presence of a unique Type IV class C pilus, known as tight adherence (Tad), in virulent Aeromonas hydrophila (vAh). In the present study, we sought to functionalize the role of Tad pili in the pathogenicity of A. hydrophila ML09-119. Through a comprehensive comparative genomics analysis of 170 A. hydrophila genomes, the conserved presence of the Tad operon in vAh isolates was confirmed, suggesting its potential contribution to pathogenicity. Herein, the entire Tad operon was knocked out from A. hydrophila ML09-119 to elucidate its specific role in A. hydrophila virulence. The absence of the Tad operon did not affect growth kinetics but significantly reduced virulence in catfish fingerlings, highlighting the essential role of the Tad operon during infection. Biofilm formation of A. hydrophila ML09-119 was significantly decreased in the Tad operon deletant. Absence of the Tad operon had no effect on sensitivity to other environmental stressors, including hydrogen peroxide, osmolarity, alkalinity, and temperature; however, it was more sensitive to low pH conditions. Scanning electron microscopy revealed that the Tad mutant had a rougher surface structure during log phase growth than the wildtype strain, indicating the absence of Tad impacts the outer surface of vAh during cell division, of which the biological consequences are unknown. These findings highlight the role of Tad in vAh pathogenesis and biofilm formation, signifying the importance of T4P in bacterial infections.

Characterization of gut microbiota in patients with stage 3-4 chronic kidney disease: a retrospective cohort study.

Multiple factors, such as dietary patterns, pharmaceutical interventions, and exposure to harmful substances, possess the capacity to influence gut microbiota composition. Gut microbiota dysbiosis has emerged as a significant contributor to the progression of chronic kidney disease (CKD) and its associated complications. By comprehending the intricacies of the intestinal microbiota, this research endeavor holds the potential to offer novel perspectives on potential strategies for mitigating CKD progression. In this retrospective analysis, we assessed gut microbiota composition in CKD patients. Fecal samples were collected from a cohort of 44 patients with stage 3-4 CKD, alongside a control group consisting of 132 healthy volunteers. Subsequently, 16s rDNA sequencing was conducted to examine the composition of the gut microbiota. Our findings revealed significant alterations in the diversity of intestinal microbiota in fecal samples between patients with stage 3-4 CKD and healthy subjects. Among the 475 bacterial genera, 164 were shared, while 242 dominant genera were exclusive to healthy subjects and 69 to CKD stages 3-4 samples. Notably, healthy volunteers exhibited a prevalence of intestinal Firmicutes and Bacteroidetes, whereas stage 3-4 CKD patients displayed higher abundance of Proteobacteria and Actinobacteria. The presence of uncultured Coprobacillus sp. notably contributed to distinguishing between the two groups. ROC curve analysis identified distinct microbiota with superior diagnostic efficacy for discriminating stage 3-4 CKD patients from healthy individuals. Metabolic pathway analysis revealed differing dominant pathways between the two groups-the NADH dehydrogenase pathway in healthy individuals and the phosphate acetyltransferase pathway in stage 3-4 CKD patients. Moreover, the CKD cohort displayed a higher proportion of Gram-negative bacteria and facultative anaerobes. In conclusion, our study underscores the profound influence of gut microbiota dysbiosis on CKD progression. The distinct microbial profiles observed in CKD patients highlight the potential efficacy of microbiota-based interventions in mitigating CKD advancement.

Antibacterial peptide Reg4 ameliorates Pseudomonas aeruginosa-induced pulmonary inflammation and fibrosis.

Pseudomonas aeruginosa (P. aeruginosa) is a Gram-negative facultative anaerobe that has become an important cause of severe infections in humans, particularly in patients with cystic fibrosis. The development of efficacious methods or mendicants against P. aeruginosa is still needed. We previously reported that regenerating islet-derived family member 4 (Reg4) has bactericidal activity against Salmonella Typhimurium, a Gram-negative flagellated bacterium. We herein explore whether Reg4 has bactericidal activity against P. aeruginosa. In the P. aeruginosa PAO1-chronic infection model, Reg4 significantly inhibits the colonization of PAO1 in the lung and subsequently ameliorates pulmonary inflammation and fibrosis. Reg4 recombinant protein suppresses the growth motility and biofilm formation capability of PAO1 in vitro. Mechanistically, Reg4 not only exerts bactericidal action via direct binding to the P. aeruginosa cell wall but also enhances the phagocytosis of alveolar macrophages in the host. Taken together, our study demonstrates that Reg4 may provide protection against P. aeruginosa-induced pulmonary inflammation and fibrosis via its antibacterial activity.IMPORTANCEChronic lung infection with Pseudomonas aeruginosa is a leading cause of morbidity and mortality in patients with cystic fibrosis. Due to the antibiotic resistance of Pseudomonas aeruginosa, antimicrobial peptides appear to be a potential alternative to combat its infection. In this study, we report an antimicrobial peptide, regenerating islet-derived 4 (Reg4), that showed killing activity against clinical strains of Pseudomonas aeruginosa PAO1 and ameliorated PAO1-induced pulmonary inflammation and fibrosis. Experimental data also showed Reg4 directly bound to the bacterial cell membrane and enhanced the phagocytosis of host alveolar macrophages. Our presented study will be a helpful resource in searching for novel antimicrobial peptides that could have the potential to replace conventional antibiotics.

Isolation and Detection of UreC and UreR of Proteus mirabilis in Gastrointestinal Samples from Patients with Crohn's Disease in Iraq

Proteus mirabilis is a Gram-negative facultative anaerobe bacillus isolated from the human gastrointestinal tract that has recently been linked to Crohn's disease (CD) recurrence after bowel resection. CD is an inflammatory bowel disease that affects the entire gastrointestinal tract, including the mouth and anus. Inflammation, ulcers, and other damage to the digestive tract lining characterize it. In the current study, CD patients as well as controls provided 79 biopsy samples of both sexes and ages from the Teaching Hospital Gastroenterology and Hepatology, medical city, Baghdad, from October 2022 to March 2023, to detect Proteus mirabilis P. mirablis bacteria, as well as the results of biochemical tests and the Vitek 2 system. P. mirablis was subjected to a PCR assay using particular primers that targeted the genes ureR and Urease C (ureC), which encode for the urease enzyme, a virulence factor in Proteus species.

Is maxillary sinusitis and radiographic maxillary sinus opacification associated with an altered microbiology of MRONJ?

ObjectiveMaxillary sinusitis can be a sequela of medication-related osteonecrosis of the jaw (MRONJ). This study aims to characterize the microbiome of maxillary MRONJ with concurrent maxillary sinusitis and radiographic maxillary sinus opacification to determine if there is a relationship between the microbiome of MRONJ and sinus disease. Study DesignThis retrospective case series was conducted using electronic health records from the University of Pennsylvania and affiliated hospitals. The target population was surgically managed maxillary MRONJ patients. The primary predictor variables were tissue culture results. The primary outcomes were maxillary sinusitis or maxillary sinus opacification. Statistical analysis was performed using chi-squared tests at the 95% confidence interval. ResultsThirty-nine subjects were selected: 25 had sinus opacification and 11 had sinusitis. Resident bacteria were present in 90% of subjects, non-resident bacteria in 74%, and opportunistic organisms in 15%. There were significantly more subjects with chronic sinusitis microbes (79%) than without. There were significantly more gram-positive anaerobes, specifically Propionibacterium, as well as the gram-negative facultative anaerobe, Capnocytophaga, in subjects with concurrent sinusitis. ConclusionsMaxillary MRONJ with concurrent maxillary sinusitis may be associated with gram-positive anaerobic species, Propionibacterium, and Capnocytophaga colonization. Maxillary MRONJ patients may benefit from sinus evaluation and concurrent surgical intervention.

Acute cholecystitis with sepsis due to Edwardsiella tarda: a case report

BackgroundEdwardsiella tarda (E. tarda) is a Gram-negative facultative anaerobe belonging to Enterobacteriales and is commonly isolated from fishes and reptiles. Infection due to E. tarda is uncommon among humans, with a reported human retention rate of 0.001%. It can cause sepsis in the elderly or those with pre-existing conditions such as liver failure, autoimmune disease, or malignancy. E. tarda is susceptible to many antibiotics; however, a high mortality rate (approximately 40%) has been reported with sepsis.Case presentationA 65-year-old woman presented to our hospital with a chief complaint of fever and abdominal pain for 2 days. Her blood tests showed elevated inflammatory markers, and contrast-enhanced computed tomography showed distention and wall thickening of the gallbladder and inflammation of peri-gallbladder fat. Subsequently, a diagnosis of cholecystitis with systemic inflammatory response syndrome was made. Laparoscopic cholecystectomy was performed after starting antimicrobial therapy. Blood culture of samples obtained on admission were positive for E. tarda, which was also detected in bile juice culture. Therefore, she was diagnosed with bacteremia caused by E. tarda, and postoperative antimicrobial therapy was continued. The patient improved, and there were no complications.ConclusionsWe experienced an extremely rare case of acute cholecystitis caused by E. tarda. Only a few cases of acute cholecystitis due to E. tarda have been reported. Furthermore, similar to this case, no previous study has reported the detection of E. tarda in both blood and bile cultures in acute cholecystitis cases. In addition to appropriate surgical intervention, continuous administration of antibiotics based on culture results resulted in a favorable outcome.

Siderophore-producing Pantoea ferrattrahens sp. nov. isolated from a clinical specimen and Pantoea ferramans sp. nov. isolated from soil at the bottom of a pond.

Two Gram-negative facultative anaerobes were isolated from a sepsis patient with pancreatic cancer (strain PAGU 2156T ) and soil at the bottom of a pond (strain PAGU 2198T ), respectively. These two strains formed haloes around the colonies on chrome azurol S agar plates, indicating the production of siderophores. Two isolates assigned to the genus Pantoea based on the 16S rRNA gene were differentiated from established species by using polymorphic taxonomies. Phylogenetic analysis using four housekeeping genes (gyrB, rpoB, atpD, and infB) showed that strain PAGU 2156T is closely related to Pantoea cypripedii LMG 2657T (89.9%) or Pantoea septica LMG 5345T (95.7%). Meanwhile, strain PAGU 2198T formed a single clade with Pantoea rodasii DSM 26611T (93.6%) and Pantoea rwandensis DSM 105076T (93.3%). The average nucleotide identity values obtained from the draft genome assembly showed ≤90.2% between strain PAGU 2156T and closely related species and ≤81.5% between strain PAGU 2198T and closely related species. Based on various phenotypes, biochemical properties, and whole-cell fatty acid composition compared with related species, it was concluded that each strain should be classified as a new species of the genus Pantoea. In this manuscript, Pantoea ferrattrahens sp. nov. and Pantoea ferramans sp. nov. with strain PAGU 2156T (=NBRC 115930T = CCUG 76757T ) and strain PAGU 2198T (=NBRC 114265T = CCUG 75151T ) are proposed as each type strain.

Conserved metabolic regulator ArcA responds to oxygen availability, iron limitation, and cell envelope perturbations during bacteremia.

Infections of the bloodstream are life-threatening and can result in sepsis. Gram-negative bacteria cause a significant portion of bloodstream infections, which is also referred to as bacteremia. The long-term goal of our work is to understand how such bacteria establish and maintain infection during bacteremia. We have previously identified the transcription factor ArcA, which promotes fermentation in bacteria, as a likely contributor to the growth and survival of bacteria in this environment. Here, we study ArcA in the Gram-negative species Citrobacter freundii, Klebsiella pneumoniae, and Serratia marcescens. Our findings aid in determining how these bacteria sense their environment, utilize nutrients, and generate energy while countering the host immune system. This information is critical for developing better models of infection to inform future therapeutic development.

SERRATIA LIQUEFACIENS SEPTICEMIA SECONDARY TO CONTAMINATED MULTIVITAMINS

SERRATIA LIQUEFACIENS SEPTICEMIA SECONDARY TO CONTAMINATED MULTIVITAMINS

The antibacterial effect of Plectranthus scutellarioides (L.) R.Br. leaves extract against bacteria associated with peri-implantitis

Background and aimThe present study investigates Plectranthus scutellarioides (L.) R.Br. as potential antibacterial oral rinse against bacteria associated with peri-implantitis to prevent the initial infection as well as disease progression. Experimental procedurePhytochemical screening was done on P. scutellarioides lyophilized extract to identify the presence of chemical constituent by using mass-based identification. The extract was screened for its antibacterial activity against 4 Gram-positive aerobes (early colonizer) and 5 Gram-negative facultative anaerobes as well as obligate anaerobes (late colonizer) using disc diffusion method. The extract was tested for minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), its cytotoxicity effects on human gingival fibroblast cell (HnGF) as well as bacteria morphological changes by scanning electron microscopy (SEM). Results and conclusionFour flavonoid compounds were identified namely quercetin-3-glucoside, quercitrin, quercetin 3-(6″-acetylglucoside) and quercetin 3-O-acetyl-rhamnoside. The sensitivity test revealed that P. scutellarioides extract was effective against all the bacteria tested. MIC concentrations for the Gram-positive aerobes were in the range of 1.56–12.50 mg/mL, and the MBC concentrations were within 3.13–12.50 mg/mL. For Gram-negative obligate anaerobes, the MIC concentration were within 3.13–12.50 mg/mL and MBC within 6.25–200.00 mg/mL. The ethanolic extract did not have any cytotoxic effect on HnGF cells at the tested concentrations. SEM images showed bacterial cell wall disruption for all the bacteria tested. The results showed that P. scutellarioides extract exerts its antibacterial property by disrupting the cell wall of all the bacteria tested. Hence, P. scutellarioides may benefit from further investigations on its safety for oral use as an adjunctive treatment for peri-implantitis.

P-097 The Microbiota Difference in Normal and Abnormal Semen Samples Assessed by Real-time RCR

Abstract Study question Does microbiota differ in semen samples with normal and abnormal parameters? Summary answer The higher prevalence of obligate anaerobes and lactobacilli was more typical for semen samples with abnormal parameters compared to samples with normozoospermia. What is known already For a long time, semen in healthy men was considered to be sterile, and the detection of microorganisms was associated with pathologies. More recently, it has been shown that microbiota can be present in semen samples with normal semen parameters. Some researchers, usually using 16S RNA sequencing, cautiously suggested that certain microbial groups could be associated with norm and pathology. Study design, size, duration 825 semen samples from men who came to the “Garmonia” Medical Center (Yekaterinburg, Russia) seeking preconception care in 2019-2021, were included in the study. Depending on the spermiograms results, the samples were divided into two groups: Group 1 – normozoospermia (n = 350), Group 2 – samples with abnormal parameters (n = 475). Participants/materials, setting, methods Semen microbiota was analyzed by real-time PCR Androflor kit (DNA Technology, Russia). Detection rates of 18 bacteria/bacterial groups and 4 consolidated groups of microorganisms (obligate anaerobes (OA), gram-positive facultative anaerobes (GPFA), gram-negative facultative anaerobes GNFA), and mycoplasmas) were compared in Group 1 and Group 2. Two-tailed Fisher’s exact test was performed to check the significance of the differences. Main results and the role of chance Bacterial DNA was detected more often in the samples with abnormal spermiograms (Group 2) than in normozoospermia samples (Group 1): 79.6% and 73.4% respectively (p = 0.045). There was no difference in detection rates of GPFA, GNFA and mycoplasmas in both groups, whereas the detection rate of OA was significantly higher in Group 2 samples than in Group 1 (44.0% and 36.3%, respectively, p = 0.026). When analyzing the detection rate of different bacteria/bacterial groups we registered significant differences for 7 of them. For all the groups, the higher detection rate was associated with Group 2 (abnormal semen samples). In these samples, the detection rate of lactobacilli was 23.4% (compared to 13.7% in Group 1, p < 0.001), Megasphaera spp./Veillonella spp./Dialister spp. – 21.1 (12.0% in Group 1, p = 0.001), Bacteroides spp./Porphyromonas spp./Prevotella spp. – 26.7% (17.1% in Group 1, p = 0.001), Anaerococcus spp. – 15.2% (9.7% in Group 1, p = 0.021), Peptostreptococcus spp./Parvimonas spp. – 18.1% (12.3% in Group 1, p = 0.026), Eubacterium spp. – 24.8% (18.9% in Group 1, p = 0.043). Limitations, reasons for caution Androflor PCR kit uses the 103 genome-equivalent/ml threshold for most of the target microbial groups; samples with lower DNA level are considered as negative. Hence, it is possible that the results may be different when using another threshold. Wider implications of the findings Further research should determine the microbiota variants in semen samples with different abnormalities, such as asthenozoospermia, leukospermia, etc. These findings could expand our understanding of the contribution made by specific microorganisms to diseases, which potentially could lead to the development of new therapeutic options or improvement of the existing ones. Trial registration number Ethics Committee of Ural State Medical University (Protocol № 7 dated September 20, 2019)

SYNTHESIS, STRUCTURE AND ANTIMICROBIAL ACTIVITY OF AZOMETHINES, DERIVATIVES OF 4-(O-LUPINYL)BENZALDEHYDE

The article describes the results of studies on the synthesis and structural features of 4-lupinylbenzaldehydes and azomethine derivatives of the lupinine alkaloid. Chemical modification of the lupinine alkaloid was carried out by the halomethylene group in the C-1 position of the quinolysin backbone. The reactions were carried out in several stages. The results of the synthesis of 4-lupinylbenzaldehydes (4-hydroxybenzaldehyde and 4-hydroxy-3-ethoxy-benzaldehyde) synthons in the synthesis of biologically active substances with yields of 67.3% and 74.0%, respectively, are presented. The interaction of 4-lupinylbenzaldehyde with 4-chlorobenzylamine and vinyl ester of monoethanolamine synthesized lupinyl-containing azomethines with yields of 78.4% and 77.4%, respectively. The structure of the obtained compounds was established based on the analysis of the ¹H and 13C NMR spectra, the multiplicity of signals in the 13C NMR spectra was determined from the spectra recorded in the J-modulation mode. The assignment of signals in the spectra was carried out using various modern methods of correlation spectroscopy 1H-1H (COZY), and 1H-13C (HMBC, HSQC). The values of chemical shifts, multiplicity and integral intensity of 1H and 13C signals in one-dimensional NMR spectra are determined. Bioscreening of new 4-lupinylbenzaldehydes and azomethines was carried out, among which substances with high antimicrobial activity were identified. The antimicrobial activity of all the presented samples was studied on reference test microorganisms: facultative anaerobic gram-positive cocci of Staphylococcus aureus ATCC 6538, aerobic gram-positive spore-forming Bacillus subtilis ATCC 6633, gram-negative rods facultative anaerobes of Escherichia coli ATCC 25922 aerobic Pseudomonas aeruginosa ATCC 27853 and yeast fungus Candida albicans ATCC 10231 by diffusion into agar (wells).

Femoral artery aneurysm with large hematoma from Pasteurella: case report and literature review

BackgroundPasteurella multocida is a well-known gram-negative facultative anaerobe well known for its ability to cause soft tissue infections following animal bite or scratch. Here we present a case with mycotic aneurysm of the superficial femoral artery due to P. multocida infection.Case presentationA 62 year old male patient presented with worsening right leg pain and swelling. On examination, he was found to have profound swelling and erythema of the right medial thigh and tenderness to palpation. Computerized tomography showed findings suggestive of right femoral pseudoaneurysm with a large right medial thigh hematoma. Blood cultures grew P. multocida. Patient underwent emergent open resection of the mycotic aneurysm and vascular bypass surgery. Intraoperatively, the site was noted to be grossly infected with multiple pockets of pus which were drained and pus cultures grew P. multocida. The diagnosis of P. multocida bacteremia with right femoral mycotic aneurysm and thigh abscess was made. Patient received 6 weeks of intravenous ceftriaxone and recovered.ConclusionOur case is the first report on infection of peripheral vessel with Pasteurella and highlights the importance of prompt surgical intervention and effective antibiotic treatment

Escherichia coli urosepsis leading to native valve endocarditis

Escherichia coli, a Gram-negative facultative anaerobe, is the common causative organism leading to urinary tract infection. However, the involvement of endocardium by E. coli has been reported to be very rare in spite of the septicemia caused by this organism. However, the mortality rate due to infective endocarditis caused by E. coli was reported to be higher than due to other organisms like HACEK group of organisms. Conventional risk factors leading to infective endocarditis include cirrhosis of the liver, prosthetic heart valves, and other sources of infection like urosepsis. Here, we report the case of a 60-year-old diabetic male who presented with obstructive uropathy-induced urinary tract infection leading to infective endocarditis.

Synthesis and Investigation of the Properties of Polymer-immobilized Silver- and Gold Nanoparticles

Metal–polymer composites (MPC) based on copolymers of polypropylene glycol maleate phthalate with acrylic acid and metallic gold and silver were synthesized for the first time. The structure of nanocomposites is characterized with the help of microscopy and spectroscopy. Antimicrobial activity of novel metal-polymeric complexes based on silver and gold was studied. Metal-polymeric complexes were stabilized for the first time with polymeric matrix based on the copolymers of polypropyleneglycolmaleatephthalate with acrylic acid (p-PGMPh/AA:Ag, p-PGMPh/AA:Au). Obtained nanocomposites contain the nanoparticles of silver and gold of rhomboidal and cylindrical shapes with the sizes of 40–50 and 35–50 nm correspondingly. The size of more than 80 % of the nanoparticles are from 20 to 50 nm and has a spherical and rhombic shape. For determination of antimicrobial activity of the MPC the reference test-microorganisms such as facultative-anaerobe gram-positive Staphylococcus aureus, aerobic gram-positive spore-forming Bacillus subtilis, gram-negative facultative anaerobe of Escheriсhia coli, aerobic Pseudomonas aeruginosa and yeast fungi Сandida albicans have been used. The resulting nanocomposites are stable and promising for the creation of new pho-tochromic and nonlinear optical materials, as well as for using in medicine in the development of antiseptic and antimicrobial materials that are needed during a pandemic.

A Gut Feeling: Antibiotic Stewardship in the Setting of Multi-Drug Resistant Enterobacteriaceae Neonatal Sepsis

The role of enteric microbiota in both physiologic and pathologic processes of the human body remains an incompletely understood and rapidly developing field of inquiry. Enterobacter is a genus of gram-negative facultative anaerobes exhibiting widespread resistance to various antibiotic therapies. It belongs to the family Enterobacteriaceae, including such prominent members as Klebsiella, Escherichia, Shigella, and Salmonella. Here we present the case of an infant male on ventilatory support who developed hospital-acquired ventilator-associated pneumonia with cultures positive for multi-drug resistant (MDR) Enterobacter absuriae.

Associations of sex, oral hygiene and smoking with oral species in distinct habitats at age 32years.

The oral microbiome is ecologically diverse, complex, dynamic, and little understood. We describe the microbiota of four oral habitats in a birth cohort at age 32 and examine differences by sex, oral hygiene, and current smoking status, dental caries, and periodontal health. Oral biofilm samples collected from anterior labial supragingival, posterior lingual supragingival, subgingival, and tongue sites of 841 Dunedin Multidisciplinary Health and Development Study members were analysed using checkerboard DNA-DNA hybridization; focusing on 30 ecologically important bacterial species. The four habitats exhibited distinct microbial profiles that differed by sex. Streptococcus gordonii was more dominant in supragingival and tongue biofilms of males; Porphyromonas gingivalis exhibited higher relative abundance in subgingival biofilm of females. Males had higher scores than females for periodontal pathogens at supragingival sites. The relative abundance of several putative caries and periodontal pathogens differed in smokers and non-smokers. With poor oral hygiene significantly higher proportions of Gram-negative facultative anaerobes were present in subgingival biofilm and there were higher scores for the principal components characterised by putative cariogenic and periodontal pathogens at each site. Distinctive microenvironments shape oral biofilms and systematic differences exist by sex, oral hygiene, and smoking status.

A PRIMARY EMPYEMA OF UNKNOWN DURATION DUE TO ANAEROBIC GRAM-NEGATIVE BACILLUS HAFNIA ALVEI

TOPIC: Chest Infections TYPE: Medical Student/Resident Case Reports INTRODUCTION: Empyema is the presence of pus or bacteria in the pleural space. Incidence is increasing gradually with higher rates in the elderly with a greater prevalence in males [1]. Empyema is a fatal infection with a mortality rate of 20% [2]. Anaerobic Enterobacteriaceae accounting for less than 6% of empyema cases, are an infrequent cause [1]. CASE PRESENTATION: An 80-year-old male with a history of coronary disease, hypertension, hyperlipidemia, peripheral vascular disease, moderate aortic stenosis, a former smoker was seen at the pulmonary clinic for intermittent dyspnea with right-sided abdominal fullness of unknown duration and no symptoms of infection. He had significant asbestos exposure from his shipyard work. Around six months back, he underwent superior mesenteric artery (SMA) stenting for chronic abdominal angina. He was taking a super enzyme supplement to enhance his digestion. Chest x-ray review revealed right-sided effusion, which was also present before SMA stenting (Figure A1-2). A diagnostic thoracentesis showed brownish-green fluid with analysis indicative of empyema (Figure B). His blood work was normal. He was admitted, and a pigtail catheter was inserted into the right pleural space with purulent fluid drainage. He also underwent fibrinolysis. The pleural fluid culture grew Hafnia alvei sensitive to quinolones, aminoglycoside, and carbapenems (Amp C resistance pattern). At discharge, computed tomography and x-ray of the chest revealed empyema resolution, and the chest tube was removed (Figure C1-2). The initial antibiotic ertapenem was transitioned to levofloxacin for one month at discharge. At four weeks after discharge, his symptoms had entirely resolved DISCUSSION: H. alvei is a gram-negative facultative motile anaerobe of the Enterobacteriaceae family, a commensal in the gastrointestinal (GI) tract of humans and animals. It colonizes the oropharynx in humans [3]. It produces a cytolytic toxin, a virulent factor, causing acute gastroenteritis. It is a rare cause of nosocomial and community-acquired infection with a preference for biliary tree infection and has lower mortality [4-5]. In patients with multiple comorbidities and immunosuppressed, it causes extraintestinal diseases such as endophthalmitis, bronchopneumonia, gastroenteritis, and meningitis [5]. The infection source is the GI tract via gut translocation or oropharynx venous drainage draining into the heart and forced into the visceral pleura or alveolar capillary bed [5-6]. In our patient, another source could be the contaminated supplement (it contains Ox bile) CONCLUSIONS: In primary empyema of remote duration and an infrequent cause, a possible source could be the GI tract or the oropharynx. Clinicians should be aware of supplement contents that could be a source of infection REFERENCE #1: Godfrey MS, Bramley KT, Detterbeck F. Medical and Surgical Management of Empyema. Semin Respir Crit Care Med. 2019;40(3):361-74 REFERENCE #2: Corcoran JP, Wrightson JM, Belcher E, DeCamp MM, Feller-Kopman D, Rahman NM. Pleural infection: past, present, and future directions. Lancet Respir Med. 2015;3(7):563-77 REFERENCE #3: Fazal BA, Justman JE, Turett GS, Telzak EE. Community-acquired Hafnia alvei infection. Clin Infect Dis. 1997;24(3):527-8 DISCLOSURES: No relevant relationships by Phillip Beck, source=Web Response no disclosure on file for Wilson Grace; No relevant relationships by Ethan Karle, source=Web Response No relevant relationships by AARON MILLER, source=Web Response No relevant relationships by Shakuntala Patil, source=Web Response No relevant relationships by SACHIN PATIL, source=Web Response No relevant relationships by ANTONY RAWINDRARAJ, source=Web Response

The Hunger Games: Aggregatibacter actinomycetemcomitans Exploits Human Neutrophils As an Epinephrine Source for Survival.

Aggregatibacter actinomycetemcomitans is a gram-negative facultative anaerobe and an opportunistic oral pathogen, strongly associated with periodontitis and other inflammatory diseases. Periodontitis is a chronic inflammation of the periodontium resulting from the inflammatory response of the host towards the dysbiotic microbial community present at the gingival crevice. Previously, our group identified catecholamines and iron as the signals that activate the QseBC two-component system in A. actinomycetemcomitans, necessary for the organism to acquire iron as a nutrient to survive in the anaerobic environment. However, the source of catecholamines has not been identified. It has been reported that mouse neutrophils can release catecholamines. In periodontitis, large infiltration of neutrophils is found at the subgingival pocket; hence, we wanted to test the hypothesis that A. actinomycetemcomitans exploits human neutrophils as a source for catecholamines. In the present study, we showed that human neutrophils synthesize, store, and release epinephrine, one of the three main types of catecholamines. Human neutrophil challenge with A. actinomycetemcomitans induced exocytosis of neutrophil granule subtypes: secretory vesicles, specific granules, gelatinase granules, and azurophilic granules. In addition, by selectively inhibiting granule exocytosis, we present the first evidence that epinephrine is stored in azurophilic granules. Using QseC mutants, we showed that the periplasmic domain of the QseC sensor kinase is required for the interaction between A. actinomycetemcomitans and epinephrine. Finally, epinephrine-containing supernatants collected from human neutrophils promoted A. actinomycetemcomitans growth and induced the expression of the qseBC operon under anaerobic conditions. Based on our findings, we propose that A. actinomycetemcomitans promotes azurophilic granule exocytosis by neutrophils as an epinephrine source to promote bacterial survival.

Comparison of Antimicrobial Efficacy of Diode Laser, Ultrasonic Activated and Conventional Irrigation with 2.5% NaOCl during RCT: An Interventional Study

The aim and objective of the study was to evaluate and compare the antimicrobial efficacy of a diode laser irradiation, ultrasonic activated and conventional irrigation with 2.5% NaOCl on obligatory and facultative anaerobic bacteria in single-rooted canals. Total of 60 permanent maxillary and mandibular single-rooted (single canal) anterior teeth were selected. First microbial sample (S1) was collected after access opening and working length determination, using a sterile paper point. Cleaning and shaping were performed, with each instrument change accompanied by irrigation using 2 mL 2.5% NaOCl. After cleaning and shaping, disinfection protocol using diode laser (group1), ultrasonic activated irrigation with 2.5% NaOCl (group 2) and conventional irrigation with 2.5% NaOCl (group 3) was performed and second microbial sample (S2) was obtained. The colony characters of each type of growth on each media were noted and the organisms were identified using standard biochemical reactions. Gram-positive and gram-negative facultative anaerobe were predominantly isolated from the culture, and the highest reduction of the microbial count was seen in diode laser group with 60.92% followed by the ultrasonic group with 47.22% reduction and least reduction was observed in conventional irrigation with the ultrasonic group with 37.97%. The results were statistically significant with p-value <0.05. Diode laser disinfection showed the highest reduction of microbial count compared to ultrasonic activated and conventional needle irrigation with 2.5% NaOCl group. This study will help us to choose wisely between various irrigating methods and protocols. Diode laser in our study has shown superior disinfection of the root canals compared to others.