Isolating, identifying and evaluating of oil degradation strains for the air-assisted microbial enhanced oil recovery process.

Due to the inefficient reproduction of microorganisms in oxygen-deprived environments of the reservoir, the applications of microbial enhanced oil recovery (MEOR) are restricted. To overcome this problem, a new type of air-assisted MEOR process was investigated. Three compounding oil degradation strains were screened using biochemical experiments. Their performances in bacterial suspensions with different amounts of dissolved oxygen were evaluated. Water flooding, microbial flooding and air-assisted microbial flooding core flow experiments were carried out. Carbon distribution curve of biodegraded oil with different oxygen concentration was determined by chromatographic analysis. The long-chain alkanes are degraded by microorganisms. A simulation model was established to take into account the change in oxygen concentration in the reservoir. The results showed that the optimal dissolved oxygen concentration for microbial growth was 4.5~5.5mg/L. The main oxygen consumption in the reservoir happened in the stationary and declining phases of the microbial growth systems. In order to reduce the oxygen concentration to a safe level, the minimum radius of oxygen consumption was found to be about 145m. These results demonstrate that the air-assisted MEOR process can overcome the shortcomings of traditional microbial flooding techniques. The findings of this study can help for better understanding of microbial enhanced oil recovery and improving the efficiency of microbial oil displacement.

Neonatal septicemia at intensive care unit, Ayder Comprehensive Specialized Hospital, Tigray, North Ethiopia: Bacteriological profile, drug susceptibility pattern, and associated factors.

BACKGROUND: Neonatal septicemia is a life threatening medical emergency that requires timely detection of pathogens with urgent rational antibiotics therapy. METHODS: A cross-sectional study was conducted between March 2017 to September 2018 among 317 septicemia suspected neonates at neonatal intensive care unit, Ayder Comprehensive Specialized Hospital, Mekelle, Tigray, North Ethiopia. A 3 mL of blood was collected from each participant. Identification of bacterial species was done using the standard microbiological techniques. Antibiotic sensitivity test was done using disk diffusion method. Data were entered and analyzed using computer software SPSS version 22. Bivariate and multivariate regression analysis was applied to determine the association between variables. RESULTS: Of the 317 (190 male and 127 female) neonates, 116 (36.6%) were found to be with culture proven septicemia. Klebsiella species were the predominant etiologic agents. Length of hospital stay (AOR (adjusted odds ratio) = 3.65 (2.17-6.13), p < 0.001) and low birth weight (AOR = 1.64 (1.13-2.78), p = 0.04) were the factors associated with neonatalsepticemia. Most isolates showeda frightening drug resistance rate to the commonly used antimicrobial drugs. K. pneumoniae, E. coli, Enterobacter and Citrobacter species were 57% to100% resistant to ceftazidime, ceftriaxone, gentamycin, amoxacillin-clavulunic acid and ampicillin. All, 9 (100%) isolates of S. aureus were resistant to oxacilline, ampicillin,erythromycin and gentamycin. Furthermore, 55.6% S. aureus isolates were Methicillin Resistant Staphylococcus aureus. CONCLUSION: Neonaltal septicemia is found to be significantly high in the present study. As most of the isolates are potentially related to hospital acquired infections, prevention and control policy should have to be more strengthening in the neonatal intensive care unit.

Seed biopriming with P- and K-solubilizing Enterobacter hormaechei sp. improves the early vegetative growth and the P and K uptake of okra (Abelmoschus esculentus) seedling.

Limited information is available that seed biopriming with plant growth-promoting Enterobacter spp. play a prominent role to enhance vegetative growth of plants. Contrary to Enterobacter cloacae, Enterobacter hormaechei is a less-studied counterpart despite its vast potential in plant growth-promotion mainly through the inorganic phosphorus (P) and potassium (K) solubilization abilities. To this end, 18 locally isolated bacterial pure cultures were screened and three strains showed high P- and K-solubilizing capabilities. Light microscopy, biochemical tests and 16S rRNA gene sequencing revealed that strains 15a1 and 40a were closely related to Enterobacter hormaechei while strain 38 was closely related to Enterobacter cloacae (Accession number: MN294583; MN294585; MN294584). All Enterobacter spp. shared common plant growth-promoting traits, namely nitrogen (N2) fixation, indole-3-acetic acid production and siderophore production. The strains 38 and 40a were able to produce gibberellic acid, while only strain 38 was able to secrete exopolysaccharide on agar. Under in vitro germination assay of okra (Abelmoschus esculentus) seeds, Enterobacter spp. significantly improved overall germination parameters and vigor index (19.6%) of seedlings. The efficacy of root colonization of Enterobacter spp. on the pre-treated seedling root tips was confirmed using Scanning Electron Microscopy (SEM). The pot experiment of bioprimed seeds of okra seedling showed significant improvement of the plant growth (> 28%) which corresponded to the increase of P and K uptakes (> 89%) as compared to the uninoculated control plants. The leaf surface area and the SPAD chlorophyll index of bioprimed plants were increased by up to 29% and 9% respectively. This report revealed that the under-explored species of P- and K-solubilizing Enterobacter hormaechei sp. with multiple plant beneficial traits presents a great potential sustainable approach for enhancement of soil fertility and P and K uptakes of plants.

Screening of pectinase-producing bacteria from farmlands and optimization of enzyme production from selected strain by RSM.

Pectinolytic enzymes that catalyze the breakdown of substrates containing pectin are widespread. Pectinases have potential applications in various industries, including food, animal feed, textile, paper, and fuel. In this study, one hundred bacterial isolates were collected from Marand city farmlands (Azarbaijan-E-Sharqi, Iran) and screened by MP medium on the base of pectinase activity considering the significance of pectinases. The results depicted that three isolates showed the most pectinase activity (more massive halo). The biochemical and molecular test results showed that the three screened bacteria were Enterobacter and named Enterobacter sp. MF41, Enterobacter sp. MF84, and Enterobacter sp. MF90. Enterobacter sp. MF84 had the largest halo, so this strain was selected for the study of its produced pectinase. The results exhibited that the produced enzyme has optimum temperature and pH for activity at 30 °C and in 9, respectively. Finally, the enzyme production by Enterobacter sp. MF84 is optimized using response surface methodology (RSM) considering four factors (NH4Cl, K2HPO4, pectin, and incubation time) as variables. The results showed that the optimization procedure increased the enzyme production up to 12 times (from 1.16 to 14.16 U/mg). The Pareto analysis revealed that ammonium chloride has a significant role in decreasing the enzyme production, probably by inducing the nitrification pathway enzymes in the presence of organic nitrogen in Enterobacter sp. MF84.

Enterobacter endophthalmitis: Clinical settings, susceptibility profile, and management outcomes across two decades.

Purpose: To describe the clinical presentation and management of Enterobacter endophthalmitis and compare with previous in-house published literature. Methods: This was a retrospective interventional comparative case series involving 44 cases with culture proven Enterobacter endophthalmitis from April 2006 to August 2018 who underwent vitrectomy/vitreous biopsy, intravitreal antibiotics with or without additional procedures as appropriate. The current outcomes were compared to the outcomes previously reported a decade back from our center. The mean age at presentation, predisposing factor, number of interventions, interval between inciting event and presentation, type of intravitreal antibiotic used, anatomic, and the functional outcomes were analyzed and compared to the previous series. Results: There were 30 males. Mean age was 22.73 ± 21.35 years (median 14 years). Inciting event was open globe injury in 34 (77.27%) eyes, 4 (9.09%) eyes following cataract surgery, 3 (6.81%) eyes with endogenous endophthalmitis, 2 (4.54%) eyes following keratoplasty, and 1 eye (2.27%) following trabeculectomy. Presenting visual acuity was favorable (≥20/400) in 2 eyes (4.54%), at the final visit it was in 11 eyes (25%). The organisms were most sensitive to ciprofloxacin (95.12%), amikacin (90.47%), and ceftazidime (85.36%). A comparison of the current study with previous in-house study showed that number of eyes with presenting vision ≥20/400 as well as final vision ≥20/400 were comparable. Susceptibility was highest to ciprofloxacin 39 (95.12%) (previous series) and 33 (92%) (current series). Conclusion: Enterobacter organisms show susceptibility to ciprofloxacin, amikacin, and ceftazidime. Susceptibility profile, clinical presentations, and management remain largely similar over many years. Final outcome is unfavorable.

Purification and characterisation of a quorum quenching AHL-lactonase from the endophytic bacterium Enterobacter sp. CS66.

The quorum quenching (QQ) activity of endophytic bacteria associated with medicinal plants was explored. Extracts of the Gram-negative Enterobacter sp. CS66 possessed potent N-acylhomoserine lactone (AHL) hydrolytic activity in vitro. Using degenerate primers, we PCR-amplified an open reading frame (denoted aiiE) from CS66 that was 96% identical to the well-characterised AHL-lactonase AiiA from Bacillus thuringiensis, but only 30% was identical to AHL-lactonases from other Gram-negative species. This confirms that close AiiA homologs can be found in both Gram-positive and Gram-negative bacteria. Purified AiiE exhibited potent AHL-lactonase activity against a broad range of AHLs. Furthermore, aiiE was able to reduce the production of secreted plant cell wall-degrading hydrolytic enzymes when expressed in trans in the economically important plant pathogen, Pectobacterium atrosepticum. Our results indicate the presence of a novel AHL-lactonase in Enterobacter sp. CS66 with significant potential as a biocontrol agent.

Characterizing non-linear effects of hospitalisation duration on antimicrobial resistance in respiratory isolates: an analysis of a prospective nationwide surveillance system.

OBJECTIVES: Our objective was to systematically study the influence of length of hospital stay on bacterial resistance in relevant respiratory tract isolates. METHODS: Using prospective epidemiological data from the National Swiss Antibiotic Resistance Surveillance System, susceptibility testing results for respiratory isolates retrospectively retrieved from patients hospitalised between 2008 and 2014 were compiled. Generalized additive models were used to illustrate resistance rates relative to hospitalisation duration and to adjust for co-variables. RESULTS: In all, 19 622 isolates of six relevant and predominant species were included. Resistance patterns for the predominant species showed a species-specific and antibiotic-resistance-specific profile in function of hospitalisation duration. The oxacillin resistance profile in Staphylococcus aureus isolates was constantly increasing (monophasic). The pattern of resistance to cefepime in Pseudomonas aeruginosa was biphasic with a decreasing resistance rate for the first 5 days of hospitalisation and an increase for days 6-30. A different biphasic pattern occurred in Escherichia coli regarding amoxicillin-clavulanic acid resistance: odds/day increased for the first 7 days of hospitalisation and then remained stable for days 8-30. In the adjusted models epidemiological characteristics such as age, ward type, hospital type and linguistic region were identified as relevant co-variables for the resistance rates. The contribution of these confounders was specific to the individual species/antibiotic resistance models. CONCLUSIONS: Resistance rates do not follow a dichotomic pattern (early versus late nosocomial) as suggested by current hospital-acquired pneumonia treatment guidelines. Duration of hospitalisation rather appears to have a more complex and non-linear relationship with bacterial resistance in hospital-acquired pneumonia, also depending on host and environmental factors.

Metabolically based liver damage pathophysiology in patients with urea cycle disorders - A new hypothesis.

The underlying pathophysiology of liver dysfunction in urea cycle disorders (UCDs) is still largely elusive. There is some evidence that the accumulation of urea cycle (UC) intermediates are toxic for hepatocyte mitochondria. It is possible that liver injury is directly caused by the toxicity of ammonia. The rarity of UCDs, the lack of checking of iron level in these patients, superficial knowledge of UC and an underestimation of the metabolic role of fumaric acid, are the main reasons that are responsible for the incomprehension of the mechanism of liver injury in patients suffering from UCDs. Owing to our routine clinical practice to screen for iron overload in severely ill neonates, with the focus on the newborns suffering from acute liver failure, we report a case of citrullinemia with neonatal liver failure and high blood parameters of iron overload. We hypothesize that the key is in the decreased-deficient fumaric acid production in the course of UC in UCDs that causes several sequentially intertwined metabolic disturbances with final result of liver iron overload. The presented hypothesis could be easily tested by examining the patients suffering from UCDs, for liver iron overload. This could be easily performed in countries with a high population and comprehensive national register for inborn errors of metabolism. CONCLUSION: Providing the hypothesis is correct, neonatal liver damage in patients having UCD can be prevented by the supplementation of pregnant women with fumaric or succinic acid, prepared in the form of iron supplementation pills. After birth, liver damage in patients having UCDs can be prevented by supplementation of these patients with zinc fumarate or zinc succinylate, as well.

Assessment of two carrier materials for phosphate solubilizing biofertilizers and their effect on growth of wheat (Triticum aestivum L.).

Biofertilizers are usually carrier-based inoculants containing beneficial microorganisms. Incorporation of microorganisms in carrier material enables easy-handling, long-term storage and high effectiveness of biofertilizers. Objective of the present study was to assess enriched biogas sludge and soil as biofertilizer carriers on growth and yield of wheat. Six phosphate solubilizing strains were used in this study. Three phosphate solubilizing strains, 77-NS2 (Bacillus endophyticus), 77-CS-S1 (Bacillus sphaericus) and 77-NS5 (Enterobacter aerogenes) were isolated from the rhizosphere of sugarcane, two strains, PSB5 (Bacillus safensis) and PSB12 (Bacillus megaterium) from the rhizosphere of wheat and one halophilic phosphate solubilizing strain AT2RP3 (Virgibacillus sp.) from the rhizosphere of Atriplex amnicola, were used as bioinoculants. Phosphate solubilization ability of these strains was checked in vitro in Pikovskaya medium, containing rock phosphate (RP) as insoluble P source, individually supplemented with three different carbon sources, i.e., glucose, sucrose and maltose. Maximum phosphate solubilization; 305.6µg/ml, 217.2µg/ml and 148.1µg/ml was observed in Bacillus strain PSB12 in Pikovskaya medium containing sucrose, maltose and glucose respectively. A field experiment and pot experiments in climate control room were conducted to study the effects of biogas sludge and enriched soil based phosphorous biofertilizers on growth of wheat. Bacillus strain PSB12 significantly increased root and shoot dry weights and lengths using biogas sludge as carrier material in climate control room experiments. While in field conditions, significant increase in root and shoot dry weights, lengths and seed weights was seen by PSB12 and PSB5 (Bacillus) and Enterobacter strain 77-NS5 using biogas sludge as carrier. PSB12 also significantly increased both root and shoot dry weights and lengths in field conditions when used as enriched soil based inoculum. These results indicated that bacterial isolates having plant beneficial traits such as P solubilization are more promising candidates as biofertilizer when used with carrier materials.

Treatment Outcomes in Infections Caused by "SPICE" (Serratia, Pseudomonas, Indole-positive Proteus, Citrobacter, and Enterobacter) Organisms: Carbapenem versus Noncarbapenem Regimens.

PURPOSE: Techniques used to identify AmpC ß-lactamases in SPICE (Serratia, Pseudomonas, indole-positive Proteus, Citrobacter, and Enterobacter) organisms are not yet optimized for the clinical laboratory and are not routinely used. Clinicians are often left with an uncertainty on the choice of antibiotic when a SPICE organism is isolated. The purpose of this study was to evaluate the outcomes of carbapenem versus noncarbapenem regimens in treating bacteremia or urinary tract infection from a SPICE organism in clinical practice. METHODS: This single-center, retrospective, cohort study analyzed data from adult patients who had clinical infection with a SPICE organism isolated from blood or urine cultures. Patients were assigned to a carbapenem- or noncarbapenem-treated group. The primary end point was clinical response, defined as a resolution of signs and symptoms of infection at the end of therapy. FINDINGS: A total of 332 patients were assessed, and 145 patients met the inclusion criteria for the study. There were 20 patients who received a carbapenem, while 125 received a noncarbapenem regimen. The percentage of patients who were bacteremic was 46.2%. Clinical response overall was achieved in 80% of patients on a carbapenem versus 90.3% of patients on a noncarbapenem regimen (P = 0.24). The rate of microbiologic cure was 90% in patients on a carbapenem versus 91.2% in patients on a noncarbapenem regimen (P = 1). IMPLICATIONS: In this study in patients treated for infection with a SPICE organism in clinical practice, the rates of clinical response did not differ significantly between the carbapenem and noncarbapenem groups. Current CLSI breakpoints set for SPICE organisms may still be reliable and may not require additional testing for AmpC ß-lactamases.

Kinetic characterization of a novel acid ectophosphatase from Enterobacter asburiae.

Expression of acid ectophosphatase by Enterobacter asburiae, isolated from Cattleya walkeriana (Orchidaceae) roots and identified by the 16S rRNA gene sequencing analysis, was strictly regulated by phosphorus ions, with its optimal activity being observed at an inorganic phosphate concentration of 7 mM. At the optimum pH 3.5, intact cells released p-nitrophenol at a rate of 350.76 ± 13.53 nmol of p-nitrophenolate (pNP)/min/10(8) cells. The membrane-bound enzyme was obtained by centrifugation at 100,000 × g for 1 h at 4 °C. p-Nitrophenylphosphate (pNPP) hydrolysis by the enzyme follows "Michaelis-Menten" kinetics with V = 61.2 U/mg and K0.5 = 60 µM, while ATP hydrolysis showed V = 19.7 U/mg, K0.5 = 110 µM, and nH = 1.6 and pyrophosphate hydrolysis showed V = 29.7 U/mg, K0.5 = 84 µM, and nH = 2.3. Arsenate and phosphate were competitive inhibitors with K i = 0.6 mM and K i = 1.8 mM, respectively. p-Nitrophenyl phosphatase (pNPPase) activity was inhibited by vanadate, while p-hydroxymercuribenzoate, EDTA, calcium, copper, and cobalt had no inhibitory effects. Magnesium ions were stimulatory (K0.5 = 2.2 mM and nH = 0.5). Production of an acid ectophosphatase can be a mechanism for the solubilization of mineral phosphates by microorganisms such as Enterobacter asburiae that are versatile in the solubilization of insoluble minerals, which, in turn, increases the availability of nutrients for plants, particularly in soils that are poor in phosphorus.

Exopolysaccharide produced by Enterobacter sp. YG4 reduces uranium induced nephrotoxicity.

Uranium nephrotoxicity is a health concern with very few treatment options. Bacterial exopolysaccharides (EPS) possess multiple biological activities and appear as prospective candidates for treating uranium nephrotoxicity. This study focuses on the ability of an EPS produced by a bacterial strain Enterobacter sp. YG4 to reduce uranium nephrotoxicity in vivo. This bacterium was isolated from the gut contents of a slug Laevicaulis alte (Férussac). Based on the aniline blue staining reaction and infrared spectral analysis, the EPS was identified as ß-glucan and its molecular weight was 11.99×10(6)Da. The EPS showed hydroxyl radical scavenging ability and total antioxidant capacity in vitro. To assess the protection provided by the EPS against uranium nephrotoxicity, a single dose of 2mg/kg uranyl nitrate was injected intraperitoneally to albino Wistar rats. As intervention, the EPS was administered orally (100mg/kg/day) for 4 consecutive days. The rats were sacrificed on the fifth day and analyses were conducted. Increased serum creatinine and urea nitrogen levels and histopathological alterations in kidneys were observed in uranyl nitrate treated animals. All these alterations were reduced with the administration of Enterobacter sp. YG4 EPS, emphasizing a novel approach in treating uranium nephrotoxicity.

Antibiotic therapy for diabetic foot infections in a tertiary care hospital in Jakarta, Indonesia.

AIMS: The purpose of this study was to determine the microbiology of diabetic foot infections and to assess the antibiotic susceptibility patterns. MATERIALS AND METHODS: A cross sectional retrospective study of 35 patients with diabetic foot infections hospitalized at the internal medicine clinic of Dr. Mintohardjo Navy Hospital, Jakarta. The data were collected from patient medical records retrospectively. The classification of the diabetic foot infections was evaluated according to Meggit-Wagner's Classification. Identification of causative microorganisms was performed by standard microbiologic methods. Antibiotic susceptibility testing was performed using disk-diffusion method. RESULTS: During January to December 2012, a total of 288 of diabetic patients were admitted to hospital, and 35 patients had diabetic foot infections. According to Meggit-Wagner's classification the most common disease was grade 3 in 31.4% patients, followed by grade 2 in 25.7%, and grade 4 in 17.3% of patients. Conservative diabetic control care was carried out in 37.1% of patients, and surgical intervention was carried out in 62.9% of patients. A total of 59 pathogens were identified. The most common infecting microorganism isolated on pus cultures was Staphylococcus aureus (47.5%), followed by Pseudomonas spp (16.9%), E. coli (10.2%), Streptococcus spp. (8.5%), Enterobacter spp. (7.0%), Proteus spp. (6.7%), and Acinetobacter spp. (3.2%). Overall, 37.2% of the diabetic foot infection caused by a single microorganism, and 62.8% had polymicrobial infections. The most frequently administrated antibiotic was ceftriaxone (40.0%), followed by ciprofloxacin (11.4%), and meropenem (8.6%). CONCLUSION: Diabetic foot infections (62.8%) were polymicrobial. S. aureus was most commonly found in the foot infection. Most of the microorganisms isolated from diabetic foot infection were resistant to many types of antibiotics.

Optimization of liquid media and biosafety assessment for algae-lysing bacterium NP23.

To control algal bloom caused by nutrient pollution, a wild-type algae-lysing bacterium was isolated from the Baiguishan reservoir in Henan province of China and identified as Enterobacter sp. strain NP23. Algal culture medium was optimized by applying a Placket-Burman design to obtain a high cell concentration of NP23. Three minerals (i.e., 0.6% KNO3, 0.001% MnSO4·H2O, and 0.3% K2HPO4) were found to be independent factors critical for obtaining the highest cell concentration of 10(13) CFU/mL, which was 10(4) times that of the control. In the algae-lysing experiment, the strain exhibited a high lysis rate for the 4 algae test species, namely, Chlorella vulgari, Scenedesmus, Microcystis wesenbergii, and Chlorella pyrenoidosa. Acute toxicity and mutagenicity tests showed that the bacterium NP23 had no toxic and mutagenic effects on fish, even in large doses such as 10(7) or 10(9) CFU/mL. Thus, Enterobacter sp. strain NP23 has strong potential application in the microbial algae-lysing project.

Multiple antibiotic-resistant bacteria on fluted pumpkin leaves, a herb of therapeutic value.

Fluted pumpkin (Telfairia occidentalis) is a minimally-processed green leafy vegetable traditionally used for its antianaemic properties in the form of leaf juice without a heating or inactivation step before consumption. The aim of the study was to assess the presence of surface microbiota on T. occidentalis leaves and also to determine the antimicrobial susceptibility of isolated organisms. Bacterial contaminants on 50 samples of T. occidentalis leaves were isolated and characterized using standard biochemical methods and the antimicrobial susceptibility of isolated organisms was determined using the antibiotic disc diffusion assay. The results obtained show that the leaves of T. occidentalis is contaminated with organisms which included Enterobacter agglomerans (25.9%), Proteus vulgaris (24.9%), Klebsiella spp. (2.6%), and Serratia liquefaciens (2.1%). Other bacterial isolates recovered in order of frequency included: Staphylococcus spp. (33.7%), Bacillus spp. (8.3%), and Pseudomonas fluorescens (2.6%). Of the 193 bacterial isolates from the leaves of T. occidentalis samples tested for antimicrobial resistance, all (100%) were found to be resistant to ampicillin, cloxacillin, augmentin, erythromycin, and tetracycline while 96% of the isolates were resistant to cephalothin. Resistance to trimethoprim (93%) and gentamicin (83%) was also observed. Approximately, 22% of the isolates were resistant to ciprofloxacin; however, only 11 (5.8%) were resistant to ofloxacin. Thus, uncooked T. occidentalis is a potential source of highly-resistant epiphytic bacteria which could be opportunistic pathogens in consumers.

A new approach to the analysis of antibiotic resistance data from hospitals.

We aimed to develop a new approach to the analysis of antimicrobial resistance data from the hospitals, which allows simultaneous analysis of both individual- and population-level determinants of bacterial resistance. This was a retrospective cohort study that included adult patients who stayed in the hospital >2 days. We analyzed data using shared frailty Cox models and tested our approach using a priori hypotheses based on biology and epidemiology of antibiotic resistance. For gram-negative bacteria, the use of the major selecting antibiotic by an individual was the main risk factor for acquiring resistant species. Hazard ratios (HRs) were strikingly high for ceftazidime-resistant Enterobacter species (HR=11.17; 95% confidence interval [CI]: 5.67-22.02), ciprofloxacin-resistant Pseudomonas aeruginosa (HR=4.41; 95% CI: 2.14-9.08), and imipenem-resistant P. aeruginosa (HR=7.92; 95% CI: 4.35-14.43). Ward-level use was significant for vancomycin-resistant enterococci (VRE) (HR=1.40; 95% CI: 1.07-1.83) and for imipenem-resistant P. aeruginosa (HR=1.40; 95% CI: 1.08-1.83). Previous incidence of infection in the same ward increased the risk of acquiring methicillin-resistant Staphylococcus aureus (HR=1.22; 95% CI: 1.15-1.30) and VRE (HR=1.53; 95% CI: 1.38-1.70). Our results were consistent with our hypotheses and showed that combining population- and individual-level data is crucial for the exploration of antimicrobial resistance development.

Calcium carbonate precipitation by heterotrophic bacteria isolated from biofilms formed on deteriorated ignimbrite stones: influence of calcium on EPS production and biofilm formation by these isolates.

Heterotrophic CaCO3-precipitating bacteria were isolated from biofilms on deteriorated ignimbrites, siliceous acidic rocks, from Morelia Cathedral (Mexico) and identified as Enterobacter cancerogenus (22e), Bacillus sp. (32a) and Bacillus subtilis (52g). In solid medium, 22e and 32a precipitated calcite and vaterite while 52g produced calcite. Urease activity was detected in these isolates and CaCO3 precipitation increased in the presence of urea in the liquid medium. In the presence of calcium, EPS production decreased in 22e and 32a and increased in 52g. Under laboratory conditions, ignimbrite colonization by these isolates only occurred in the presence of calcium and no CaCO3 was precipitated. Calcium may therefore be important for biofilm formation on stones. The importance of the type of stone, here a siliceous stone, on biological colonization is emphasized. This calcium effect has not been reported on calcareous materials. The importance of the effect of calcium on EPS production and biofilm formation is discussed in relation to other applications of CaCO3 precipitation by bacteria.

Isolation and characterization of xanthan-degrading Enterobacter sp. nov. LB37 for reducing the viscosity of xanthan in petroleum industry.

A Gram-negative, straight rod and facultative anaerobic bacterium was isolated from soil sample. It exhibits the phenotypic characteristics consistent with its classification in the genus Enterobacter. The isolate ferment glucose to acid and gas. Arginine dihydrolase, ornithin decarboxylase and gelatinase but not deoxyribonuclease was produced by this isolate. There was no hydrogen sulfide production. On the basis of the phenotypic data, together with phylogenetic analysis based on 16S rDNA gene sequences, this strain should represent a novel species of the genus Enterobacter and was designated as LB37. The strain LB37 could degrade xanthan molecules resulting in the rapid decrease of the viscosity of xanthan solution used in oil drilling process. Endoxanthanase activity was also detected in the culture supernatant. To our knowledge, it is the first report on the microbes being involved in the xanthan degradation for oil industry. The isolate LB37 would be useful for potential application in enhanced oil recovery and oil drilling field.

Non-surgical management of thyroid abscess with ultrasound-guided fine-needle application of an antibiotic followed by sclerotization with absolute alcohol.

Thyroid abscess is a relatively rare yet dramatic condition of the thyroid gland requiring immediate therapeutic intervention. Traditionally, more or less aggressive surgical approaches and administration of broad-spectrum antibiotics have been used. Clinically less severe disease allows non-surgical treatment as well. The case report describes successful treatment of a large abscess of iatrogenic origin after biopsy of a cystic cavity. A combination of broad-spectrum antibiotics was used based on culture results, administered both orally and by repeated application directly into the abscess cavity using an ultrasound-guided fine-needle approach. Concurrent repeated evacuation of the cavity replaced drainage. Ultimately, a small residual cavity with sterile contents was managed by sclerotization with absolute alcohol. Clinical condition permitting, thyroid abscess may be successfully treated by repeated application of a targeted antibiotic, using a fine needle and ultrasound guidance, directly into the abscess cavity, with repeated evacuation replacing drainage.

Antimicrobial resistance patterns of uropathogens among children in Istanbul, Turkey.

Urinary tract infections are a common cause of end-stage renal disease in Turkey. This prospective study investigated the antibiotic resistance patterns of uropathogens in order to recommend appropriate therapeutic protocols for children with urinary tract infections in Istanbul, Turkey. Between October 2007 and October 2008, children presenting with a first episode of urinary tract infection to a pediatric outpatient clinic were enrolled in the study. Urine samples were cultured, and antimicrobial susceptibility testing was performed. Children with proven urinary tract infections underwent imaging studies where available. A total of 126 children with a first episode of community-acquired urinary tract infection were enrolled in the study. The median age was 60.6 months; 84.1% of the children were female. Of the 126 urine samples, Escherichia coli was the leading uropathogen (81.7%), followed by Proteus spp (7.1%), Klebsiella spp (4.0%), Enterococcus spp (3.2%), Enterobacter spp (2.4%), and Pseudomonas spp (1.6%). Among the isolated uropathogens, resistance to ampicillin (85.0%), amoxicillin-clavulanate (73.8%), cefazolin (37.3%) and trimethoprim-sulfamethoxazole (42.9%) was remarkable. A large number of Enterococcus species were resistant to all antimicrobial agents except vancomycin. A country-based evaluation of antibiotic susceptibility is needed to modify antibiotic treatment. Resistance to antimicrobial agents commonly used to treat urinary tract infections (nitrofurantoin, cefixime) is less a problem than resistance to other antimicrobials (aminopenicillins, cephalosporins, trimethoprim-sulfamethoxazole) frequently prescribed for other indications.