Gram-negative Aerobic Bacterium Research Articles

Mechanisms of Acinetobacter baumannii Capsular Polysaccharide Cleavage by Phage Depolymerases

Aerobic gram-negative bacterium Acinetobacter baumannii has recently become one of the most relevant pathogens associated with hospital-acquired infections worldwide. A. baumannii produces a capsule around the cell, which represents a thick viscous layer of structurally variable capsular polysaccharide (CPS). The capsule protects the bacteria against unfavorable environmental factors and biological systems, including bacteriophages and host immune system. Many A. baumannii phages have structural depolymerases (tailspikes) that specifically recognize and digest bacterial CPS. In this work, we studied the interaction of tailspike proteins of four lytic depolymerase-carrying phages with A. baumannii CPS. Depolymerases of three bacteriophages (Fri1, AS12, and BS46) were identified as specific glycosidases that cleave the CPS of A. baumannii strains 28, 1432, and B05, respectively, by the hydrolytic mechanism. The gp54 depolymerase from bacteriophage AP22 was characterized as a polysaccharide lyase that cleaves the CPS of A. baumannii strain 1053 by β-elimination at hexuronic acid (ManNAcA) residues.

Pukyongia salina gen. nov., sp. nov., a novel genus in the family Flavobacteriaceae.

A Gram-negative aerobic bacterium, designated RR4-38T, was isolated from a biofilter in a seawater recirculating aqua-culture system (RAS) in Busan, South Korea. The bacteria were irregular, short, rod-shaped, non-motile, oxidase-positive, and catalase-negative. Growth of the strain RR4-38T was observed at 15-35·C (optimum, 25-30·C), pH 5.5-9.5 (optimum, pH 8.0), and in the presence of 0-5% (w/v) NaCl (optimum, 3%). Phylogenetic analysis based on the 16S rRNA gene sequences showed that the strain RR4-38T formed a distinct lineage with close genera Ulvibacter (≤ 95.01% 16S rRNA gene sequence similarity), Aureitalea (94.74%), Aureisphaera (≤ 93.27%), and Jejudonia (93.07%) that all belong to the family Flavobacteriaceae. Whole-genome sequence comparison revealed that the ANI (average nucleotide identity) and digital DDH (DNA-DNA hybridization) values between strain RR4-38T and the two closest strains, Ulvibacter antarcticus DSM 23424T and Aureitalea marina S1-66T, were 68.96-69.88% and 17.4-19%, respectively. The genome analysis revealed that the strain might be involved in biodegradation of organic debris produced by farmed fish in aquaculture systems. The predominant respiratory quinone was menaquinone MK-6 and the major cellular fatty acids were iso-C15:0 (26.5%), iso-C17:0 3-OH (16.4%), iso-C15:1 G (15%), and iso-C16:0 3-OH (9.6%). The major cellular polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, unidentified aminolipids, and glycolipids. Based on phenotypic, chemotaxonomic, and phylogenetic features, strain RR4-38t represents a novel genus and species in the family Flavobacteriaceae, for which the name Pukyongia salina gen. nov., sp. nov. is proposed. The type strain is RR4-38T (= KCTC 52651T = DSM 108068T).

2606. A Divergent Ferrichrome Receptor Associated with an Insertional Element (IS3) Identified on Novel Locus in Clinical Strain of Pseudomonas aeruginosa

Background Pseudomonas aeruginosa is an aerobic Gram-negative bacterium that causes life-threatening acute and chronic infections in humans. Genotypic mutations and phenotypic variations are key features of its antimicrobial resistance and adaptation to the host environment. Pyoverdine associated genes and divergent receptors play a key role in acute Pseudomonas infections. This study seeks to address the heterogeneity of ferrichrome-iron receptor (fpvA) expression, its effect on pathogenicity and its propensity to cause acute infections clinically. Genetic and phenotypic variation of a clinical isolates of P. aeruginosa (PA097 and PA115) were identified by complete genome sequencing method.MethodsAn IRB-approved prospective study collected 38 P. aeruginosa clinical isolates and stored at Carilion Medical Center. Two genetically unrelated clinical strains were selected from tracheal aspirates: PA097 and PA115. These isolates were characterized by pyoverdine (pvd) quantification in planktonic culture filtrate at OD405 nm. Multiplex PCR was carried out using primers for fpvA receptors. Quantification of iron acquisition was done on chrome azurol S (CAS) agar. Genomes for PA115 and PA097 were sequenced by Illumina Next-generation DNA sequencing.ResultsGenome assembly shows a 6.3 Mb genome size in PA115 with G+C content of 66.4%. Seven insertion sequence elements were located. We found a 101 kb locus for pvD and a highly diversified fpvA associated with an insertional element (IS3). PA115, exhibits rich green pigment of pvd followed by PAO1 and PA097 in LB media (Figure 1A) and also in Planktonic culture filtrate (Fig 1B) for quantitative estimation of pvd (Figure 1C). On CAS agar, PA115 showed high uptake of iron by orange pigment compared with lower pigmentation in PAO1 and PA097 (Fig 1D). We confirmed the ferrichrome-iron receptor as fpvAIIb in PA115 by Multiplex PCR seen in sequencing of PA115 (Figure 2).ConclusionWe found high genetic and phenotypic variation in clinical isolate of P. aeruginosa (PA115) from an acute pneumonia patient. The novel IS element found in its receptor gene locus suggests an increased role in pvd expression and iron uptake from the host. Increased pvd expression and diversified fpvAIIb association with an IS3 element may indicate higher virulence in the PA115 strain. Disclosures All authors: No reported disclosures.

Isolation and characterization of a novel benzophenone-3-degrading bacterium Methylophilus sp. strain FP-6

Benzophenone-3 (BP-3) is extensively applied in sunscreens and some other related cosmetic products. It is necessary to efficiently and safely remove BP-3 from environments by application of various treatment technologies. However, to the authors' knowledge, BP-3 biodegradation by a single bacterial strain has not been reported before. In this study, a Gram-negative aerobic bacterium capable of degrading BP-3 as a sole carbon source was isolated from a municipal wastewater treatment plant and classified as Methylophilus sp. FP-6 according to BIOLOG GEN III and 16S rDNA analysis. Methanol was chosen for further experiments as a co-metabolic carbon source to enhance the microbial degradation efficiency of BP-3. Orthogonal and one-way experiments were all performed to investigate the optimal culture conditions for degradation of BP-3 by Methylophilus sp. FP-6. The degradation rate of BP-3 reached about 65% after 8 days of incubation with strain FP-6 under optimal culture conditions. The half-life (t1/2) of BP-3 biodegradation by strain FP-6 was estimated as 2.95 days according to the BP-3 degradation curve. The metabolite intermediates generated during the BP-3 degradation process were analyzed by LC–MS/MS and three metabolite products were identified. According to the analysis of metabolic intermediates, three pathways for degradation of BP-3 by strain FP-6 were proposed. The results from this study gave first insights into the potential of BP-3 biodegradation by a single bacterial strain.

Genetic Diversity among Pseudomonas aeruginosa Isolated From Different Sources in Al-Diwaniyah City, Iraq Using RAPD-PCR Technique

Pseudomonas aeruginosa is an aerobic Gram-negative bacterium which has emerged as one of the most problematic nosocomial pathogens. To characterizes P. aeruginosa strains that are widespread in patients in Al-Diwaniyah city, 30 clinical and environment samples were collected from general hospitals of Al-Diwaniyah city. Methods for isolation and identifying P. aeruginosa based upon culture methods coupled with biochemical tests, A total of 11 amplified DNA fragments ranging in size from 250 to 1 Kpb were observed using two random amplified polymorphic DNA (RAPD) primers (opX-13, op Y-04) where as22 polymorphic amplified fragments were commonly detected among the 6 p. aeuroginosa isolates and each of primer give different genetic profiles. The results shows the RAPD-PCR analysis is a good epidemiological screening method to detect genetic variation among pseudomonas aeuroginosa isolates.

Dual RNA-seq uncovers the immune response of Larimichthys crocea to the secY gene of Pseudomonas plecoglossicida from the perspective of host-pathogen interactions

Pseudomonas plecoglossicida is a Gram-negative aerobic bacterium that causes high mortality and serious economic losses in some commercial marine fish. Expression of secY was found to be significantly upregulated at 18 °C compared to 28 °C by RNA-seq and qRT-PCR. All five tested recombinant vectors (pCM130/tac + shRNA) significantly reduced secY mRNA levels in P. plecoglossicida. The recombinant vector encoding shRNA-1165 exhibited the best gene-silencing efficiency, 82.4% and was used to create an RNAi strain for further studies. Compared with the wildtype strain, infections of Larimichthys crocea with the RNAi strain resulted in a 2-day delay in onset time and a 35% reduction in mortality, as well as the alleviation of spleen symptoms. The spleens of L. crocea infected by the wild type or RNAi strain of P. plecoglossicida were subjected to dual RNA-seq at 2 dpi. Compared with the wildtype strain, infection of P. plecoglossicida with the RNAi strain resulted in significant changes in the transcriptomes of both host and pathogen. KEGG analysis showed that the complement and coagulation cascade and the Toll-like receptor signalling pathway were the most enriched host pathways. In the pathogen, genes of the “Sec secretion system” were significantly downregulated. This downregulation of “Sec secretion system” genes hindered the secretion of bacterial proteins and reduced the virulence of P. plecoglossicida. Thus, it was easier for L. crocea to clear the RNAi strain of P. plecoglossicida, and the immune response was similarly reduced. The results indicated that secY was a virulence gene of P. plecoglossicida and played roles in the host-pathogen interactions of L. crocea and P. plecoglossicida.

Characterization of Lysobacter capsici strain NF87–2 and its biocontrol activities against phytopathogens

Strain NF87–2 is an aerobic, non-motile and rod-shaped Gram-negative bacterium. It was isolated from the rhizosphere of green pepper. In the present study, sequence analyses of the 16S rRNA and copA genes revealed that strain NF87–2 belongs to the species Lysobacter capsici. Strain NF87–2 could produce chitinase, cellulase, protease and siderophore. The strain showed a broad spectrum of antifungal activities against phytopathogens, including Alternaria brassicae, Rhizoctonia solani, Sclerotinia sclerotiorum, Botrytis cinerea, Colletotrichum gloeosporioides and Fusarium oxysporum. The secondary metabolites secreted by strain NF87–2 could inhibit the growth of both bacteria and fungi, but the mixture of peptides and proteins extracts from a suspension of strain NF87–2 could only inhibit the mycelia growth of fungi. Our results also have shown that strain NF87–2 could control pepper damping off caused by R. solani effectively in a greenhouse setting. Our findings provide a new source for a biocontrol agent and shed light on the mechanism of the antagonistic activity of L. capsici.

Utilising novel antimicrobial peptides identified from the rumen microbiome as a potential treatment for multiple A. baumannii strains

Antibiotic and antimicrobial resistance is a global issue, not only for medical and veterinary treatment, but also for economic development. One of the critical bacterial pathogens known to develop resistance to antimicrobial agents is Acinetobacter baumannii, one of the ESKAPE pathogens. A. baumannii is an aerobic Gram-negative coccobacillus bacterium associated with bacteraemia, urinary tract infections and ventilator-associated pneumonia, and is typically viewed as an opportunistic pathogen. Previous research has shown that clinical strains of A. baumannii have susceptibility to novel antimicrobial peptides, specifically those identified from a rumen metagenomic dataset. Using standardised 96 well MIC testing, 3 antimicrobial peptides (Lynronne-1, Lynronne-2, Lynronne-3, identified as part of a previous research project by the Huws Lab) were compared against multiple strains of A. baumannii, in order to show efficacy of treatment against a wider variety of strains. Of the strains tested, a number were clinical isolates with demonstrated resistance (imipenem resistant, OXO-23/OXO-50). The results show that the antimicrobial peptides had noticeable inhibitory effects on the bacterial growth. There was also variation between the 3 peptides utilised, with Lynronne-1 appearing to have the lowest MIC over the majority of the strains tested. Further research as part of this project will utilise other identified antimicrobial peptides, including rationally designed peptides, as well as potentially using another gastrointestinal microbiome metagenomic dataset to identify a greater number of novel antimicrobial peptides.

A case of ulceroglandular tularemia presenting with lymphadenopathy and an ulcer on a linear morphoea lesion surrounded by erysipelas

Tularemia is a zoonosis caused by the infection of Francisella tularensis (a gram-negative aerobic bacterium). Transmission to other animals or humans usually occurs through insect or tick bites, direct contact with a contaminated environment (mud or water), infected animals – mainly lagomorphs – or by ingesting undercooked meat or inhaling contaminated dust (hay or soil). This paper discusses the case of a 32-year-old man, who came to our Emergency Room presenting with persistent fever, inguinal lymphadenopathy, and an ulcer on his left lower limb on a linear morphoea lesion that had been there for some time. The lesion was surrounded by erysipelas. After hospitalization and tests, the patient was diagnosed with ulceroglandular tularemia. Antibiotic treatment with doxycycline resolved the clinical picture, but not the morphoea lesion.

Global mRNA decay and 23S rRNA fragmentation in Gluconobacter oxydans 621H

BackgroundGluconobacter oxydans is a strictly aerobic Gram-negative acetic acid bacterium used industrially for oxidative biotransformations due to its exceptional type of catabolism. It incompletely oxidizes a wide variety of carbohydrates regio- and stereoselectively in the periplasm using membrane-bound dehydrogenases with accumulation of the products in the medium. As a consequence, only a small fraction of the carbon and energy source enters the cell, resulting in a low biomass yield. Additionally, central carbon metabolism is characterized by the absence of a functional glycolysis and absence of a functional tricarboxylic acid (TCA) cycle. Due to these features, G. oxydans is a highly interesting model organism. Here we analyzed global mRNA decay in G. oxydans to describe its characteristic features and to identify short-lived mRNAs representing potential bottlenecks in the metabolism for further growth improvement by metabolic engineering.ResultsUsing DNA microarrays we estimated the mRNA half-lives in G. oxydans. Overall, the mRNA half-lives ranged mainly from 3 min to 25 min with a global mean of 5.7 min. The transcripts encoding GroES and GroEL required for proper protein folding ranked at the top among transcripts exhibiting both long half-lives and high abundance. The F-type H+-ATP synthase transcripts involved in energy metabolism ranked among the transcripts with the shortest mRNA half-lives. RNAseq analysis revealed low expression levels for genes of the incomplete TCA cycle and also the mRNA half-lives of several of those were short and below the global mean. The mRNA decay analysis also revealed an apparent instability of full-length 23S rRNA. Further analysis of the ribosome-associated rRNA revealed a 23S rRNA fragmentation pattern exhibiting new cleavage regions in 23S rRNAs which were previously not known.ConclusionsThe very short mRNA half-lives of the H+-ATP synthase, which is likely responsible for the ATP-proton motive force interconversion in G. oxydans under many or most conditions, is notably in contrast to mRNA decay data from other bacteria. Together with the short mRNA half-lives and low expression of some other central metabolic genes it could limit intended improvements of G. oxydans’ biomass yield by metabolic engineering. Also, further studies are needed to unravel the multistep process of the 23S rRNA fragmentation in G. oxydans.

STENOTROPHOMONAS PNEUMONIA IN AN IMMUNOCOMPETENT INDIVIDUAL

SESSION TITLE: Chest Infections 3 SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: 10/09/2018 01:15 PM - 02:15 PM INTRODUCTION: Stenotrophomonas maltophilia is an aerobic gram-negative bacterium that has become more prominent in the past decade. It has often been associated with nosocomial infections, particularly in immunocompromised patients. We have identified and successfully treated a healthy, immunocompetent patient who developed a community acquired severe S. maltophilia pneumonia CASE PRESENTATION: 34 y/o M with history of methadone dependence presented to the ED with 3 days of worsening nausea, vomiting and fever. He was found to be febrile, tachycardic, tachypneic and in significant distress. Laboratory testing revealed leukocytosis and lactic acidosis. CXR showed right lower lobe consolidation. Given the severity of his presentation and concern for aspiration he was started on empiric vancomycin, piperacillin/tazobactam and azithromycin. He became progressively hypoxic and tachypneic and was intubated and admitted to the ICU. He developed septic shock and an increasing FiO2 requirement. Sputum cultures grew Streptococcus pyogenes which was thought to be a contaminant given the clinical course. In light of worsening sepsis, antibiotics were escalated to vancomycin, meropenem, and azithromycin but there was no clinical improvement. Testing for immunodeficiency was done including HIV testing which was negative and immunoelectrophoresis and serum immunoglobulins w ere normal. CT-scan of the chest showed progression of consolidation to involvement of the entire right lung. BAL was performed on day 3 and grew S. maltophilia, sensitive only to trimethoprim-sulfamethoxazole (TMP-SMX). Given this he was started on TMP-SMX after which his condition improved. He was extubated after 3 days and finished a 10 day course of TMP-SMX. DISCUSSION: S. maltophilia is an environmental bacterium found in aqueous habitats. It is typically a nosocomial pathogen and represents 3.3% of hospital associated bacterial pneumonia, as well as bacteremia, endocarditis, UTIs and meningitis. Reported cases of community-acquired S. maltophilia have involved patients with comorbidities such as COPD, trauma, indwelling catheters, prior antibiotic use, malignancy, HIV, or other immunosuppressive state. However, our patient had none of these predisposing risk factors and investigations for an immunocompromised state were negative. Hence while being a recognized nosocomial pathogen, this case demonstrates that S. maltophilia infection may occur in a patient without risk factors and should be considered in the differential diagnosis of the febrile patient CONCLUSIONS: This case suggests that infections with S. maltophilia may also occur in healthy, immunocompetent community dwelling individuals and it is therefore important for clinicians to be aware of this possibility. With increasing awareness of infection with this organism antibiotic stewardship will have an important role in limiting the development of antibiotic resistance Reference #1: Brooke, J. S. (2012). Stenotrophomonas maltophilia: AnEmerging Global Opportunistic Pathogen. ClinicalMicrobiology Reviews, 25(1), 2–41. Reference #2: Jones, R. (2010). Microbial Etiologies of Hospital-AcquiredBacterial Pneumonia and Ventilator-Associated BacterialPneumonia. Clinical Infectious Diseases, 51, S81-S87. Reference #3: Falagas ME, Kastoris AC, Vouloumanou EK, Dimopoulos G.Community-acquired Stenotrophomonas maltophiliainfections: a systematic review. Eur J Clin Microbiol InfectDis 2009;28:719-730 DISCLOSURES: No relevant relationships by Monika Mishra, source=Web Response

Applicability of endochitinase of Flavobacterium johnsoniae with transglycosylation activity in generating long-chain chitooligosaccharides

Chitin and its derivatives are used for a variety of applications. Flavobacterium johnsoniae UW101 is an aerobic Gram-negative bacterium. Genome analysis of F. johnsoniae UW101 revealed the presence of 10 glycoside hydrolases (GHs) that may degrade or modify chitin. The gene encoding chitinase B (FjchiB), which encodes a single catalytic GH18 domain has been cloned and heterologously expressed in Escherichia coli. FjChiB was optimally active in 50 mM sodium citrate buffer (pH 6.0) at 40 °C. FjChiB was salt-tolerant and catalytically versatile, with substrate specificity towards 75% DDA (degree of de-acetylation) chitosan, followed by colloidal chitin. Chitotetraose (DP4) was the shortest of the oligomeric substrates used by FjChiB. The Km and Vmax values of FjChiB for colloidal chitin were 49.38 mg/ml and 11.2 nanokat mg−1, respectively. The overall catalytic efficiency (kcat/Km) of FjChiB was 1.40 × 103 mg−1 ml s−1. FjChiB exhibited transglycosylation (TG) with chitopentaose (DP5) and chitohexaose (DP6) substrates. The TG by FjChiB was fine-tuned by introducing a tryptophan (G106W) and asparagine (D148N) in the highly conserved catalytic groove and catalytic center, respectively. Hydrolytic products profile and homology modelling indicated that FjChiB is an endochitinase that holds promise for the conversion of chitin into useful products through both TG and/or hydrolysis.

The major outer membrane protein of Legionella pneumophila Lpg1974 shows pore-forming characteristics similar to the human mitochondrial outer membrane pore, hVDAC1

Legionella pneumophila is an aerobic and nonspore-forming pathogenic Gram-negative bacterium of the genus Legionella. It is the causative agent of Legionnaires' disease, also known as Legionellosis. The hosts of this organism are diverse, ranging from simple water borne protozoans such as amoebae to more complex hosts such as macrophages in humans. Genome analyses have shown the presence of genes coding for eukaryotic like proteins in several Legionella species. The presence of these proteins may assist L. pneumophila in its adaptation to the eukaryotic host. We studied the characteristics of a protein (Lpg1974) of L. pneumophila that shows remarkable homologies in length of the primary sequence and for the identity/homology of many amino acids to the voltage dependent anion channel (human VDAC1, Porin 31HL) of human mitochondria. Two different forms of Lpg1974 were overexpressed in Escherichia coli and purified to homogeneity: the one containing a putative N-terminal signal sequence and one without it. Reconstituted protein containing the signal sequence formed ion-permeable pores in lipid bilayer membranes with a conductance of approximately 5.4 nS in 1 M KCl. When the predicted N-terminal signal peptide of Lpg1974 comprising an α-helical structure similar to that at the N-terminus of hVDAC1 was removed, the channels formed in reconstitution experiments had a conductance of 7.6 nS in 1 M KCl. Both Lpg1974 proteins formed pores that were voltage-dependent and anion-selective similar to the pores formed by hVDAC1. These results suggest that Lpg1974 of L. pneumophila is indeed a structural and functional homologue to hVDAC1.

Raoultella ornithinolytica Isolation in Cloacal Microbiota of Tinamus solitarius: Preliminary Data

ABSTRACT Raoultella ornithinolytica is a gram-negative aerobic bacterium belonging to Enterobacteriaceae family, an emerging pathogen that causes several pathogenic conditions in man, with little veterinary importance; however, its identification is underestimated by conventional laboratory techniques. The present study reports the identification of R. ornithinolytica in Tinamus solitaries, during a routine sanitary evaluation of aerobic enterobacteria in cloacal microbiota of birds belonging to the Guira Oga Center, Puerto Iguazu, Argentina. The sample was preliminary classified as Klebsiella spp.; however, after the use of the MALDI-TOF MS technique it was identified as R. ornithinolytica. The sample was submitted to an antimicrobial susceptibility test, where it showed a similar pattern profile as reported in the literature, with resistance to ampicillin and other β-lactam antibiotics. It is possible that Raoultella spp are more common in birds as it is reported. Therefore, review studies on bacteria collections of avian origin, as well as cases with confirmation of Klebsiella, should be deeply evaluated in laboratorial routine, mainly due to the pathogenic potential of R. ornithinolytica for Poultry, as well as for public health.

Evaluation of the Effects of Nutritional and Environmental Parameters on Extracellular Protease Production by Stenotrophomonas acidaminiphila Strain BPE4

An aerobic mesophilic Gram-negative rod-shaped bacterium isolated from fermenting bean processing effluent (BPE) and identified as Stenotrophomonas acidaminiphila strain BPE4, produced an extracellular protease on skimmed-milk minimal medium. Time-course of enzyme production revealed peak productivity at 12 h but enzyme concentration gradually increased till 36 h beyond which both concentration and productivity gradually decreased. Evaluation of the influences of major nutritional sources on enzyme concentration revealed significant (P < 0.05) effects of fermentation time and nutrient sources, with corn steep liquor and NH4Cl emerging as best carbon and nitrogen sources respectively. The study also selected K2HPO4/KH2PO4 (2:1) and 108 cfu/mL as most appropriate phosphate combination and inoculum size respectively for maximum release of protease within the fermentation time of 36 h. One unit of proteolytic activity was defined as the amount of crude enzyme that digested 1 mg of azocasein in one minute under the assay conditions. Assessment of optimum conditions of temperature and pH for test enzyme activity revealed optimum enzyme activity of 158.83 U/mL (2647.70 nkatal) at 40°C and pH 9.0 suggesting protease of the alkaline kind. The enzyme was specific for casein as a protein substrate. Stenotrophomonas acidaminiphila strain BPE4 could be exploited for commercial production of extracellular protease on corn steep liquor as a waste management option and industrial applications.

Stenotrophomonas maltophilia: A Rare Cause of Recurrent Necrotizing Pancreatitis

Stenotrophomonas maltophilia is an aerobic Gram-negative bacterium that is well known for its capacity to produce biofilms. It has recently been implicated as an emerging nosocomial pathogen in cases of pneumonia, endocarditis, and septic arthritis, particularly in patients that are immunosuppressed or admitted to intensive care units. S. maltophilia is also known for its resistance to multiple conventional pharmacological therapies, including some cephalosporins and carbapenems. We present one of the few cases of S. maltophilia causing necrotizing pancreatitis. Our case involves a 73-year-old male who presented from an outside facility after undergoing a protracted five-week course of severe pancreatitis complicated by subsequent sepsis, acute hypoxic respiratory failure, and pancreatic pseudocyst formation. Due to a decline in clinical status, magnetic resonance imaging of the abdomen was obtained, which noted two enlarging pancreatic pseudocysts and new areas of pancreatic necrosis causing gastric outlet obstruction. Blood cultures were obtained and showed no evidence of bacterial growth, however endoscopic drainage of one of the pancreatic pseudocysts yielded Enterobacter cloacae, Enterococcus faecium, and S. maltophilia. The patient underwent recurrent endoscopic ultrasonography with debridement of necrotic tissue in attempts to relieve the obstruction, along with cystogastrostomy stent placement. The patient was initially treated with broad spectrum antibiotics including vancomycin and meropenem, and then transitioned to a regimen of linezolid and trimethoprim/sulfamethoxazole. Despite aggressive antibiotic therapy and necrotic tissue debridement, the patient did not survive. Treatment of S. maltophilia associated pancreatitis is still highly contested, as this organism is resistant to many antibiotics and even has varying susceptibilities to the preferred treatment modalities—fluoroquinolones and trimethoprim-sulfamethoxazole. Recent cases have noted increasing prevalence of S. maltophilia in bloodstream and hepatobiliary infections, thereby increasing the possibility that it may become a common causative organism of necrotizing pancreatitis in the future. This case illustrates the importance of continued research regarding appropriate antibiotic coverage for necrotizing pancreatitis and possible need for early initiation of targeted antibiotics, as S. maltophilia becomes more prevalent.

Severe Pansinusitis Due to Raoultella Ornithinolytica

Raoultella ornithinolytica is a gram-negative aerobic bacterium typically found in plants, soil and water. Reports of Raoultella ornithinolytica causing infections in humans, especially in the head and neck, are rare. Herein we report a case of a woman with severe septal deviation, chronic headaches and facial pain who was revealed to have Raoultella ornithinolytica pansinusitis incidentally noted during an endoscopic septoplasty. Raoultella ornithinolytica was isolated from cultures of the diffuse purulent drainage found in her maxillary and ethmoid sinuses. This case indicates that while a rare cause of head and neck infection in humans, Raoultella ornithinolytica can be found as the causative pathogen in severe sinusitis.

Metagenome-Assembled Draft Genome Sequence of a Novel Microbial Stenotrophomonas maltophilia Strain Isolated from Caenorhabditisremanei Tissue.

ABSTRACTStenotrophomonas maltophilia is a Gram-negative aerobic bacterium and emerging nosocomial pathogen. Here, we present a draft genome sequence for an S. maltophilia strain assembled from a metagenomic DNA extract isolated from a laboratory stock of the nematode worm Caenorhabditis remanei.

Legionella pneumophila: Diagnosis and Management for the Critically Ill and Septic Patient: A Review of the Literature

Legionnaires disease (LD) is caused by a gram-negative aerobic bacterium, Legionella pneumophila, which is an important cause of both community-acquired and nosocomial pneumonia. Although an uncommon pathogen, L. pneumophila is associated with significant morbidity and mortality if left untreated. The clinical manifestations surrounding LD are often unreliable for diagnosis, underlining the importance of the urinary antigen test and cultures of the lower respiratory tract. As a primarily intracellular atypical organism, treatment modalities aimed at penetrating the bacterial cell wall are preferred and include the use of fluoroquinolones and macrolides. Several studies have attempted to determine the treatment of choice for L. pneumophila; however, no current algorithm exists. Prevention of LD is aimed at proper maintenance of building cooling towers, plumbing design, and construction, in addition to chemoprophylaxis in a subgroup of immunocompromised patients. In this review we outline the clinical manifestations with subsequent diagnosis, summarize the available diagnostic tools for LD, and evaluate the current literature regarding treatment and management.

Rapid Identification of Pseudomonas aeruginosa by Using Real Time PCR

Pseudomonas aeruginosa is an aerobic Gram-negative bacterium which has emerged as one of the most problematic nosocomial pathogens.To characterizes P. aeruginosa strains that are widespread in patients in Iraq, 90 clinical samples were collected from wounds, burn, ear infection and urinary tract infection taken from three general hospitals of different areas of the region in Baghdad . Methods for isolation and identifying P. aeruginosa based upon culture methods coupled with biochemical tests, were used in this study. The results show that, the selective medium (cetrimide agar) at 42˚C aerobically had highest recovery in the isolation of P. aeruginosa strains, they were produced greenish-yellow or blue pigment colonies, catalase and oxidase was positive whereas negative for methyl red, and indole.; however, some of these methods are time consuming and may not be very accurate whereas API 20E is rapid method which performs at least 20 different biochemical tests at once, however it proved difficult to obtain additional information concerning the relationship between these strains. Molecular study for identifying p.aeruginosa include DNA extraction , than Real time assay by using powerchek P. aeruginosa Real time PCR Kit with probe, the results showed that RT-PCR has found to be rapid and more sensitive and specific in identification of P. aeruginosa, however Real time PCR Kit with probe, specific marker is recommended