Authors:Farideh Rahmani, Abbas Fooladi, Seyed Marashi and Mohammad Nourani
Cholera is a serious epidemic and endemic disease caused by the Gram-negative bacterium Vibrio cholerae. SXT is an integrative conjugation element (ICE) that was isolated from a V. cholerae; it encodes resistance to the antibiotics chloramphenicol, streptomycin and sulfamethoxazole/trimethoprim. One hundred seven V. cholerae O1 strains were collected from cholera patients in Iran from 2005 to 2007 in order to study the presence of SXT constin and antibiotic resistance.The study examined 107 Vibrio cholerae strains isolated from cholera prevalent in some Iranian provinces. Bacterial isolation and identification were carried out according to standard bacteriological methods. Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) to four antibiotics (chloramphenicol, streptomycin, sulfamethoxazole, and trimethoprim) were determined by broth microdilution method. PCR was employed to evaluate the presence of established antibiotic resistance genes and SXT constin using specific primer sets.The resistance of the clinical isolates to sulfamethoxazole, trimethoprime, chloramphenicol, and streptomycin was 97%, 99%, 99%, and 90%, respectively. The data obtained by PCR assay showed that the genes sulII, dfrA1, floR, strB, and sxt element were present in 95.3%, 95.3%, 81.3%, 95.3%, and 95.3% of the V. cholerae isolates.The Vibrio strains showed the typical multidrug-resistance phenotype of an SXT constin. They were resistant to sulfamethoxazole, trimethoprime, chloramphenicol, and streptomycin. The detected antibiotic resistance genes included dfrA for trimethoprim and floR, strB, sulII and int, respectively, for chloramphenicol, streptomycin, sulfamethoxazole, as well as the SXT element.
Authors:Sezer Okay, Erkan Özcengiz and Gülay Özcengiz
Pasteurella multocida is a pathogenic bacterium causing many diseases that are of significant economic importance to livestock industries. Outer membrane protein H (ompH) gene and two fragments of Pasteurella lipoprotein E (plpE) gene, namely plpEN and plpEC, were cloned from P. multocida A:3. Three DNA vaccine formulations, namely pCMV-ompH, pCMV-plpEN-ompH and pCMV-plpEC-ompH and two protein-based prototype vaccines, alum adjuvanted PlpEN-OmpH and PlpEC-OmpH, were generated. Antibody levels were induced in mice vaccinated with chimeric DNA or protein vaccines. A significant (p < 0.05) increase in serum IFN-g titer was obtained by vaccination with 100 μg of pCMV-ompH, pCMV-plpEC-ompH and PlpEC-OmpH. DNA vaccines did not provide protection upon intraperitoneal challenge with 10 LD50 of live P. multocida A:3. However, 40% protection was conferred by 100 μg of PlpEC-OmpH which was not statistically significant. These results showed that plpEN-ompH and plpEC-ompH chimeric DNA vaccines and alum adjuvanted PlpEN-OmpH or PlpEC-OmpH protein vaccines were immunogenic but not protective against P. multocida A:3 in mice. Prime-boost strategies, i.e. priming with DNA vaccines and boost with protein formulations or different adjuvants can be utilized to obtain significant protection.
Authors:Hernani S. Barud, Clóvis A. Ribeiro, Jorge M. V. Capela, Marisa S. Crespi, Sidney. J. L. Ribeiro and Younes Messadeq
Cellulose can be obtained from innumerable sources such as cotton, trees, sugar cane bagasse, wood, bacteria, and others. The bacterial cellulose (BC) produced by the Gram-negative acetic-acid bacterium Acetobacter xylinum has several unique properties. This BC is produced as highly hydrated membranes free of lignin and hemicelluloses and has a higher molecular weight and higher crystallinity. Here, the thermal behavior of BC, was compared with those of microcrystalline (MMC) and vegetal cellulose (VC). The kinetic parameters for the thermal decomposition step of the celluloses were determined by the Capela-Ribeiro non-linear isoconversional method. From data for the TG curves in nitrogen atmosphere and at heating rates of 5, 10, and 20 °C/min, the Eα and Bα terms could be determined and consequently the pre-exponential factor Aα as well as the kinetic model g(α). The pyrolysis of celluloses followed kinetic model on average, characteristic for Avrami–Erofeev with only small differences in activation energy. The fractional value of n may be related to diffusion-controlled growth, or may arise from the distributions of sizes or shapes of the reactant particles.
The quality of sour cream production from homogenised cream in the 1970's was highly improved. The heat resistance of product remained badly, that is, it precipitated in hot food. The Hungarian Dairy Research Institute (HDRI) has elaborated a technology that eliminates this disadvantageous characteristic: it is the use of exopolysaccharide (EPS)-producing lactic acid bacteria. This bacterium produces no aroma, and the proliferation optima of EPS-producing and aroma-producing lactic acid bacteria cultures do not coincide. Detection of these two bacteria was done until now by gene technology, that is expensive and long lasting one. We have applied (at first as we know) isotherm calorimetric method to follow the simultaneous proliferation of these bacteria and it was determined that: both lactic acid bacteria cultures proliferate well at the non-optimal temperature of 30°C and the thermophilic EPS-producing culture was faster than that of the mesophilic aroma-producer. The two cultures do not inhibit each other in mixed culture, and the ratio in mixed culture was 79% EPS-producer and 21% aroma-producer.
Authors:Magda Yehia El Seify, Eman Mahmoud Fouda, Hanan Mohamed Ibrahim, Maha Muhammad Fathy, Asmaa Al Husseiny Ahmed, Walaa Shawky Khater, Noha Nagi Mohammed Salah El Deen, Heba Galal Mohamed Abouzeid, Nancy Riyad Ahmed Hegazy and Heba Salah Sayed Elbanna
While recognizing the etiology of community-acquired pneumonia is necessary for formulating local antimicrobial guidelines, limited data is published about this etiology in Egyptian pediatric patients.
To determine the frequency of bacterial and viral pathogens causing community-acquired pneumonia (CAP) among immunocompetent Egyptian infants and preschool children.
Ninety infants and preschool-age children admitted to our hospital with CAP were prospectively included in the study. Etiological agents were identified using conventional bacteriological identification methods and IgM antibodies detection against common atypical respiratory bacteria and viruses.
An etiology was identified in 59 patients (65.5%). Bacterial pathogens were detected in 43 (47.8%) of the cases while viral pathogens were detected in 23 (25.5%). Coinfection with more than one etiologic agent was evident in seven patients (7.8%). The most common typical bacterial cause of pneumonia was Staphylococcus aureus (n = 12, 13.3%), followed by Streptococcus pneumoniae and Klebsiella pneumoniae (n = 7, 7.8%, each). The commonest atypical bacterium was Mycoplasma pneumoniae (n = 10, 11.1%), whereas the commonest viral etiology was influenza viruses (n = 11, 12.2%).
Although we could not determine the causative agent in some studied cases, this study provides preliminary data regarding the spectrum and frequency of microorganisms causing CAP in Egyptian infants and preschool children.
Authors:Rolf L. W. Petersen, Christian F. P. Scholz, Anders Jensen, Holger Brüggemann and Hans B. Lomholt
Progressive macular hypomelanosis (PMH) is a skin disorder that is characterized by hypopigmented macules and usually seen in young adults. The skin microbiota, in particular the bacterium Propionibacterium acnes, is suggested to play a role.
Here, we compared the P. acnes population of 24 PMH lesions from eight patients with corresponding nonlesional skin of the patients and matching control samples from eight healthy individuals using an unbiased, culture-independent next-generation sequencing approach. We also compared the P. acnes population before and after treatment with a combination of lymecycline and benzoylperoxide.
We found an association of one subtype of P. acnes, type III, with PMH. This type was predominant in all PMH lesions (73.9% of reads in average) but only detected as a minor proportion in matching control samples of healthy individuals (14.2% of reads in average). Strikingly, successful PMH treatment is able to alter the composition of the P. acnes population by substantially diminishing the proportion of P. acnes type III.
Our study suggests that P. acnes type III may play a role in the formation of PMH. Furthermore, it sheds light on substantial differences in the P. acnes phylotype distribution between the upper and lower back and abdomen in healthy individuals.
Authors:Sofia Stokkou, Gernot Geginat, Dirk Schlüter and Ina Tammer
Sepsis represents a life-threatening infection requiring the immediate start of antibacterial treatment to reduce morbidity. Thus, laboratories use direct antimicrobial susceptibility testing (AST) to rapidly generate preliminary results from positive blood cultures. As the direct AST has not yet been published to be evaluated with EUCAST breakpoints, the purpose of the study was to investigate the reliability of the direct agar diffusion test to correctly produce AST results from positive monobacterial blood cultures compared with the VITEK2-based definitive AST, when current EUCAST breakpoints were used.A total of 428 isolates from unselected monobacterial routine blood cultures and 110 challenge strains were included. Direct agar diffusion-based and standard VITEK2-based AST of 2803 bacterium-drug combinations yielded a total clinical category agreement of 95.47% with 1.28% very major errors and 3.42% combined major and minor errors. On the species level, very major errors were observed in the species-drug combinations Enterococcus spp.-high-level gentamicin (10.87%) and Staphylococcus spp.-rifampicin (5%), only. No very major errors occurred with Enterobacteriaceae and Pseudomonas aeruginosa.In most species-drug combinations, the direct agar diffusion test using EUCAST breakpoints precisely predicted the result of the definitive antibiotic susceptibility test and, thus, it can be used to optimize empiric antibiotic therapy until definitive results are available.
Authors:L. A. Ganuelas, N. Li, P. Yun, N. Hunter and Charles A. Collyer
The crystal structure of the K1 domain, an adhesin module of the lysine gingipain (Kgp) expressed on the cell surface by the periodontopathic anaerobic bacterium, Porphyromonas gingivalis W83, is compared to the previously determined structures of homologues K2 and K3, all three being representative members of the cleaved adhesin domain family. In the structure of K1, the conformation of the most extensive surface loop is unexpectedly perturbed, perhaps by crystal packing, and is displaced from a previously reported arginine-anchored position observed in K2 and K3. This displacement allows the loop to become free to interact with other proteins; the alternate flipped-out loop conformation is a novel mechanism for interacting with target host proteins, other bacteria, or other gingipain protein domains. Further, the K1 adhesin module, like others, is found to be haemolytic in vitro, and so, functions in erythrocyte recognition thereby contributing to the haemolytic function of Kgp. K1 was also observed to selectively bind to haem-albumin with high affinity, suggesting this domain may be involved in gingipain-mediated haem acquisition from haem-albumin. Therefore, it is most likely that all cleaved adhesin domains of Kgp contribute to the pathogenicity of P. gingivalis in more complex ways than simply mediating bacterial adherence.
Authors:Márta Knausz, Gabriella Kaproncai and Ferenc Rozgonyi
A nosocomialis fertőzések fő okozói az egészségügyi többletkiadásoknak és szoros összefüggésben állnak a betegbiztonság problémakörével is. Hatékony infekciókontrollal, szigorított higiénés intézkedésekkel, célzott szűrővizsgálatokkal a kórházi fertőzések 30%-a megelőzhető. Napjainkban a methicillinrezisztens
az egyik legfontosabb nosocomialis patogén. Az ellene történő védekezés lépései jól ismertek, ezért választottuk ezt a kórokozót költséghatékonysági vizsgálatainkhoz. Kiszámoltuk a győri Petz Aladár Megyei Oktatókórházban kétéves periódus alatt lezajlott methicillinrezisztens
okozta járvány költségeit és szembeállítottuk a szűrővizsgálatok költségeivel. Eredményeinket összehasonlítottuk a nemzetközi szakirodalmi adatokkal is. Megállapíthatjuk, hogy a szűrővizsgálatok költségei jóval alacsonyabbak, mint a kórházi fertőzések kezelésének költségei, ezért elsődleges szerepe a prevenciónak van.
A peptikus fekélybetegség kóroktana és klinikai megjelenési formái átalakulóban vannak. A
-fertőzés mellett a nem szteroid gyulladáscsökkentők és a kis dózisú acetilszalicilsav-kezelés kóroki szerepe ismert. A
-pozitív fekélybetegség a baktérium eradikációjával gyógyítható. Az NSAID-fekély megelőzésére a savszekréció-gátló adását pedig a gyomor-bél rendszeri, valamint szív-ér rendszeri kockázati tényezők határozzák meg. A számos kóroki tényező és az új, hatékony kezelési módok alkalmazása ellenére továbbra is vannak megválaszolatlan kérdések. Előtérbe kerültek az NSAID- és a
negatív fekélyek, amelyek száma növekszik, kezelésük tisztázásra vár. A
-eradikáció sikertelensége is gyakoribbá vált, az optimális kezelési mód hiányzik.