Analysis of clinical characteristics of infections caused by Shewanella species.

PURPOSE: The Shewanella genus is a rare pathogen of marine origin. In recent years, there has been a continuous increase in infection cases caused by this bacterium, and we have observed the uniqueness of infections caused by this microorganism. MATERIALS AND METHODS: This study conducted a retrospective analysis of the medical history and laboratory examination data of patients infected with the Shewanella genus over the past decade. Additionally, it employed bioinformatics methods to analyze the relevant virulence factors and antibiotic resistance genes associated with the Shewanella genus. RESULTS: Over the past 10 years, we have isolated 51 cases of Shewanella, with 68.82% being Shewanella putrefaciens (35/51 cases) and 31.37% being Shewanella algae (16/51 cases). Infected individuals often had underlying diseases, with 39.22% (20/51) having malignant tumors and 25.49% (13/51) having liver and biliary system diseases primarily characterized by stones. The majority of patients, 62.74% (32/51), exhibited mixed infections, including one case with a combination of infections from three other types of bacteria and five cases with a combination of infections from two other types of bacteria. The identified microorganisms were commonly resistant to ticarcillin-clavulanic acid (23.5%), followed by cefoperazone-sulbactam (19.6%), ciprofloxacin (17.6%), and cefotaxime (17.6%). Bioinformatics analysis indicates that Shewanella can express bile hydrolysis regulators and fatty acid metabolism regulators that aid in adapting to the unique environment of the biliary tract. Additionally, it expresses abundant catalase, superoxide dismutase, and two-component signal transduction system proteins, which may be related to environmental adaptation. Shewanella also expresses various antibiotic resistance genes, including beta-lactamases and aminoglycoside modification enzymes. Iron carriers may be one of its important virulence factors. CONCLUSIONS: We speculate that the Shewanella genus may exist as a specific colonizer in the human body, and under certain conditions, it may act as a pathogen, leading to biliary infections in the host.

Virulence, attachment and invasion of Caco-2 cells by multidrug-resistant bacteria isolated from wild animals.

Wild animals may be considered important reservoirs for bacterial pathogens and, consequently, possible sources of infection for humans. In this study, selected multidrug-resistant bacteria (Acinetobacter spp., Aeromonas salmonicida, Klebsiella pneumoniae, Pseudomonas fluorescens and Shewanella putrefaciens) isolated from wild animals were characterized on their ability to attach and invade/internalize human colonic carcinoma (Caco-2) cells. In addition, the viability of these bacteria to survive under simulated human gastrointestinal tract conditions as well as the production of virulence factors (homoserine lactones signal molecules, gelatinases, proteases, siderophores and biofilm formation) were studied. The results suggests that all the bacteria presented the capacity to attach and internalize into Caco-2 cells. A. salmonicida and P. fluorescens exhibited the highest ability to internalize. These bacteria were also found to be the highest proteases producers. A. salmonicida and K. pneumoniae survived under simulated human gastrointestinal conditions. These were the bacteria with the highest capacity to produce biofilms. K. pneumoniae was the only bacterium producing siderophores. Taken together, the present results reinforce the need for the "One Health" initiative, underscoring the environment and the animals as important reservoirs of infectious determinants.

A Rare Colonization in Peritoneum After Blunt Abdominal Trauma: S. putrefaciens and S. cerevisiae

BACKGROUND: Shewanella spp. are gram-negative bacteria, saprophytes, and rarely pathogenic. Saccharomyces cerevisiae is the well-known yeast used for fermentation in industry and molecular biology for research. In humans, it is a very rare pathogen which colonizes the digestive tract, and its utility has been linked to the treatment and prevention of diarrhea associated with Clostridium difficile. CASE REPORT: A 27-year-old male, victim of aggressive, blunt trauma with a 4-day history of symptoms was admitted to our surgery unit. Abdominal sonography revealed peritoneal fluid in all spaces with fibrin. We performed laparotomy and observed perforations on the ileum and general peritonitis with pus. Following surgery, patient was admitted to the intensive care unit with septic shock. The antibiogram from the peritoneal liquid revealed S. putrefaciens and S. cerevisiae. CONCLUSION: Although very rare, S. putrefaciens and S. cerevisiae may colonize in the peritoneum after blunt abdominal trauma.

Palmar Soft Tissue Infection From Shewanella putrefaciens.

Shewanella putrefaciens, a gram-negative bacillus, ubiquitous in marine environments, is an opportunistic agent reported to cause rare human infection, most commonly in patients who are immunocompromised or who have a preexisting soft tissue defect. We present an immunocompetent, 40-year-old woman with a soft tissue infection of the left palm caused by S. putrefaciens. The patient's infection was complicated by the presence of retained foreign bodies, seashell fragments, from a traumatic fall. Following appropriate evaluation and surgical treatment, our patient experienced a successful outcome with no recurrence of infection or deficit in the affected hand. This case report complements the growing literature regarding morbidity attributed to S. putrefaciens infection.

[Osteomyelitis due to Shewanella putrefaciens: case report and literature review]. / Osteomielitis por Shewanella putrefaciens: reporte de caso y revisión de literatura.

Shewanella putrefaciens is a Gram-negative bacillus and marine pathogen that rarely causes disease in humans. We report a case of osteomyelitis by this organism in a 48-year-old male patient, who presented with pain and erythema of the right foot that was initially diagnosed as cellulitis and did not revert despite treatment. He was transferred to Lima where osteomyelitis was diagnosed and started on empirical treatment with partial regression. A biopsy and culture of the compromised area found S. putrefaciens. The infection was treated according to the antibiotic sensitivity profile of the pathogen. S. putrefaciens infection represents a rare opportunistic infection of devitalized or exposed areas of the body. It is associated with residence in coastal areas and commonly affects the skin and soft tissues. Exceptional cases of osteomyelitis have been reported, but this is the first that involves the metatarsal bones.

Shewanella putrefaciens es un bacilo Gram negativo, patógeno marino que rara vez ocasiona enfermedad en humanos. Se presenta un caso de osteomielitis por este microorganismo en un paciente varón de 48 años, procedente de Chimbote. Presentó dolor y eritema en el pie derecho, inicialmente diagnosticado como celulitis, pero que no revirtió pese al tratamiento. Fue transferido a Lima donde se diagnosticó osteomielitis e inició tratamiento empírico con escasa mejoría. Por ello, se realizó una biopsia y cultivo de la zona comprometida, el metatarso, en el cual se aisló Shewanella putrefaciens. Se trató de acuerdo al perfil de sensibilidad. La infección por Shewanella putrefaciens representa una rara infección oportunista, que se localiza en áreas desvitalizadas o expuestas del cuerpo. Se asocia a vivir en zonas costeras, afectando comúnmente piel y tejidos blandos. Se han reportado casos excepcionales de osteomielitis. Este es el primero que involucra metatarso.

Shewanella putrefaciens infective endocarditis

Shewanella putrefaciens rarely causes infection in humans. In the last few decades a growing number of cases have been described. The following report outlines the case of a 40-year- old immunocompetent white man with S. putrefaciens infective endocarditis. This is the first known case of infective endocarditis due to an apparently monomicrobial S. putrefaciens infection, and the second known case of S. putrefaciens-related infective endocarditis worldwide.

Shewanella putrefaciens bacteraemia associated with terminal ileitis.

Shewanella putrefaciens has a wide geographical distribution, including sea- and fresh water, fish and soil, but it is an unusual pathogen in humans. A previously healthy boy without known immunodeficiency presented with fever, abdominal pain and diarrhoea, and a mass in the right lower quadrant. Terminal ileitis was confirmed by MRI and Shewanella putrefaciens was isolated from two separate blood cultures. This is the first report of terminal ileitis associated with Shewanella putrefaciens septicaemia.

[A rare cause of pneumonia: Shewanella putrefaciens]. / Nadir Bir Pnömoni Etkeni: Shewanella putrefaciens.

Shewanella putrefaciens is a gram-negative, non-fermentative, oxidase positive, motile bacillus that produces hydrogen sulphide. It is found widely in the nature especially in marine environments. Although it is accepted as saprophytic, different clinical syndromes, most commonly skin or soft tissue infections, have been associated with S.putrefaciens, mainly in immunocompromised cases and patients with underlying diseases. However, pneumonia cases due to S.putrefaciens are quite limited in the literature. In this report, a case of pneumonia caused by S.putrefaciens was presented. A 43-year-old female patient was admitted to our hospital with the complaints of fever, cough, sputum and weakness. The patient has had brochiectasis since childhood and has used periodical antibiotic therapies due to pneumoniae episodes. She was diagnosed to have pneumonia based on the clinical, radiological and laboratory findings, and empirical antibiotic treatment with ciprofloxacin and ceftazidime combination was initiated. Gram-stained smear of sputum yielded abundant leucocytes and gram-negative bacteria, and the isolate grown in the sputum culture was identified as S.putrefaciens by conventional methods and API 20 NE (BioMerieux, France) system. The isolate was found susceptible to ceftriaxone, ceftazidime, cefepime, ciprofloxacin, piperacillin-tazobactam, cephoperazon-sulbactam, imipenem, amikacin, gentamicin and trimethoprime-sulphametoxazole; whereas resistant to ampicillin, amoxycillin-clavulanate, cefazolin and cefuroxime, by Kirby-Bauer disk diffusion method. According to the antibiogram results, the therapy was changed to ceftriaxone (1 x 2 g, intravenous). The patient was discharged with complete cure after 14 days of therapy. In conclusion, S.putrefaciens should be considered in patients with predisposing factors as an unusual cause of pneumonia and the characteristics such as H2S production and sensitivity to third generation cephalosporins and penicillins should be used to differentiate it from Pseudomonas aeruginosa and prevent the unnecessary use of antipseudomonal antibiotics.

Quality assessment of salted, modified atmosphere packaged rainbow trout under treatment with oregano essential oil.

UNLABELLED: The present study evaluated the effect of oregano essential oil (EO) on fresh salted, packaged (45%CO(2)/5%O(2)/50%N(2)) rainbow trout fillets and stored for a period of 21 d at 4 °C. Treatments included the following: M1 (control without added EO), M2 (EO 0.2%, v/w), and M3 (0.4%, v/w). Populations of lactic acid bacteria (LAB), H(2)S-producing bacteria (including Shewanella putrefaciens), Enterobacteriaceae, and Pseudomonas spp. reached higher final numbers in control (M1) than for M2 and M3 samples. Under treatments M2 and M3, total volatile basic nitrogen (TVBN) and trimethylamine nitrogen (TMAN) values were lower than for M1 samples, whereas lipid oxidation, as judged by determination of thiobarbituric acid values (TBA), did not occur during the refrigerated storage period. Interestingly, treatment M2 resulted in a shelf-life extension of 7 to 8 d for the fresh trout fillets, whereas treatment M3 proved unsuitable (due to strong odor) for trout fillet preservation, as determined by sensory evaluation. PRACTICAL APPLICATION: The use of an essential oil such as oregano oil in fresh fish preservation may be considered an alternative "natural" additive, enhancing the sensory characteristics and extending the shelf life of the product.

Outbreak of Shewanella algae and Shewanella putrefaciens infections caused by a shared measuring cup in a general surgery unit in Korea.

OBJECTIVE: To control an outbreak of Shewanella algae and S. putrefaciens infections by identifying the risk factors for infection and transmission. DESIGN: Matched case-control study. SETTING: A university-affiliated tertiary acute care hospital in Seoul, Republic of Korea, with approximately 1,600 beds. PATIENTS: From June 20, 2003, to January 16, 2004, a total of 31 case patients with Shewanella colonization or infection and 62 control patients were enrolled in the study. INTERVENTIONS: Requirement to use single-use measuring cups and standard precautions (including hand washing before and after patient care and use of gloves). RESULTS: S. algae or S. putrefaciens was isolated from blood, for 9 (29.0%) of 31 patients who acquired one of the organisms; from bile, for 8 (25.8%), and from ascitic fluid, for 8 (25.8%). The attack rate of this outbreak was 5.8% (31 patients infected or colonized, of 534 potentially exposed on ward A) and the pathogenicity of the two species together was 77.4% (24 patients infected, of 31 who acquired the pathogens). The estimated incubation period for Shewanella acquisition was 3-49 days. Using logistic analysis, we identified the following risk factors: presence of external drainage catheters in the hepatobiliary system (odds ratio [OR], 20; P < .001), presence of hepatobiliary disease (OR, 6.4; P < .001), admission to the emergency department of the hospital (OR, 2.9; P = .039), wound classification of "contaminated" or "dirty or infected" (OR, 16.5; P = .012), an American Society of Anesthesiologists score of 3 or higher (OR, 8.0; P = .006), duration of stay in ward A (OR, 1.1; P < .001), and, for women, an age of 60-69 years (OR, 13.3; P = .028). A Shewanella isolate was recovered from the surface of a shared measuring cup, and 12 isolates of S. algae showed the same pulsed-field gel electrophoresis pattern. CONCLUSIONS: This Shewanella outbreak had a single-source origin and spread by contact transmission via a contaminated measuring cup. Shewanella species are emerging as potentially serious human pathogens in hospitals and could be included in hospital infection surveillance systems.

Shewanella putrefaciens keratitis in the lamellar bed 6 years after LASIK.

PURPOSE: To present a case of infectious keratitis occurring 6 years after LASIK due to the rare human pathogen Shewanella putrefaciens. METHODS: A 58-year-old man presented with redness and pain in the right eye 6 years following LASIK retreatment. Examination revealed a corneal infiltrate at the flap interface. Corneal scraping of stroma beneath the flap was submitted for histopathologic and microbiologic evaluation. RESULTS: An infiltrate located at the LASIK flap interface originated from an epithelial defect at the flap-corneal junction. Corneal stroma cultures demonstrated Shewanella putrefaciens. The infection resolved with antibiotic treatment. CONCLUSIONS: LASIK-related complications, such as infections, can occur many years following the procedure. The potential space created under the LASIK flap may predispose patients to infection by opportunistic organisms.

Shewanella putrefaciens in a fuel-in-water emulsion from the Prestige oil spill.

Microorganisms that colonize the fuel-in-water emulsion from the Prestige spill have been compared with those from Exxon-Valdez. Both emulsions contained non-fermentative gram-negative rods but unlike Exxon-Valdez's, the Prestige's spill contained anaerobic bacteria and no fungi. Our main finding has been the identification of Shewanella putrefaciens , a bacterium promising for bioremediation.

New method for rapid and sensitive quantification of sulphide-producing bacteria in fish from arctic and temperate waters.

The offensive, fishy, rotten H2S-off-odours in spoiled, aerobically and cold stored fish from arctic and temperate waters are generally caused by sulphide-producing bacteria (SPB), mainly Shewanella putrefaciens. In the present work, a new, rapid, simple and accurate method for estimation of the SPB content in fish from these areas is described. The quantification is based on the formation rate of iron sulphide during growth of SPBs incubated at 30 degrees C in a liquid growth medium containing cysteine, sodium thiosulphate and iron(III)citrate as specific substrates for iron sulphide formation. The iron sulphide turns the medium grey and masks the background fluorescence in the medium when the SPB content in the assay is approximately 10(9) cfu/ml. The fluorescence change could be detected instrumentally and the colour change visually. The method was developed and evaluated in tests with S. putrefaciens CCUG 13452 DT as well as naturally occurring SPBs in cod, salmon, wolf fish and coal fish. A linear correlation between the SPB count and detection time was obtained over the entire range from 1 to 10(9) cfu SPB/g, corresponding to detection times 17 and 1 h, respectively. The correlation is described by the equation: log cfu/g fish= -0.59(+/- 0.17) x DT+ 9.65(+/- 0.09), where DT is the detection time in hours. The model was valid for all the tested fish species and all tested naturally occurring SPBs in these species. The regression coefficients (R2) for cod, coal fish, wolf fish and salmon were 0.99, 0.92, 0.97 and 0.97, respectively. The detection level of the method is 1 SPB per sample tube, corresponding to 16 cfu/g fish. The method could be used to predict the remaining shelf life of the fish for different markets, even when the time-temperature history during storage of the fish is unknown.