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slant culture [keywords]
- Targeting chronic central nervous system HIV infection. [Comment, Journal Article, Research Support, N.I.H., Extramural]
- Antivir Ther 2012; 17(7):1227-31.
Central nervous system (CNS) HIV infection is a nearly universal facet of systemic infection. Although antiretroviral therapy is generally effective in suppressing this infection and reducing its severe complications, reports of continued neurological abnormalities have questioned whether treatment developed for systemic efficacy is optimized for CNS infection. Shikuma et al. report that a 'monocyte efficacy' score based on cell culture studies and applied to antiretroviral drugs correlated with neuropsychological performance in a previously reported cohort. Although there are important questions regarding the theoretical underpinnings of both this score and its application, the findings present a novel slant on therapy.
- Culture Method and PCR for the Detection of Helicobacter pylori in Drinking Water in Basrah Governorate Iraq. [Journal Article]
- Gastroenterol Res Pract 2012.:245167.
Helicobacter pylori is recognized by the World Health Organization to be the primary cause of peptic ulcers, chronic gastritis, and stomach cancer, though the source of human infection is not well understood. One of the problems in understanding the source of human contamination is the difficulty in isolating the organism from the environment. However, the combination of PCR results with those of culturing of 471 drinking water samples can provide a more accurate picture of H. pylori detection. In this method 78 presumptive H. pylori colonies out of 266 tap water samples were obtained in the preliminary detection on modified Columbia agar (MCUA) slant relying on urease positivity with a rate of 29.3%. However, only 11 out of them were confirmed by Gram staining and biochemical tests reducing the rate to 4.13% whereas only 3 (1.46%) from 205 reverse osmosis (RO) water samples. Furthermore, only 6 (54.5%) out of the 11 isolates from tap water and 1 (33.3%) of the 3 RO isolates were confirmed by 16SrRNA PCR. Thus PCR confirmation reduced the rate to 2.2%. In addition, only 4 (4%) of 100 tap water samples negative for H. pylori by culture method were H. pylori positive by 16SrRNA. Water samples were collected from 24 districts of Basrah Governorate from February-December 2009. The direct recovery of H. pylori from drinking water is both alarming and scientifically exciting in terms of the investigation of its epidemiology.
- Studies on non-symbiotic diazotrophic bacterial populations of coastal arable saline soils of India. [Journal Article]
- Indian J Microbiol 2011 Jul; 51(3):369-76.
The effect of fluctuations of salinity in three different seasons on diazotrophic populations and N(2) fixation in six mono cropped rice field soils of the coastal region of the Gangetic delta of West Bengal, India, was studied. The average pH, ECe, organic carbon and total nitrogen of the soils ranged from 4.99-7.08, 2.02-19.58 dSm(-1), 4.68-12.03 g kg(-1) and 0.44-1.70 g kg (-1), respectively. The average log colony forming units of the bacterial populations and N(2)-fixation in the soils varied from 4.61 to 5.86 and 2.74 to 4.52 mg N(2) fixed 50 ml (-1) culture media respectively, with the lowest value recorded in summer. Recovery of microorganisms and N(2)- fixation gradually decreased with extraneous addition of NaCl in the culture media. All the eight isolates were Gram positive, spore and capsule formers. They could utilize glucose, sucrose, mannitol, starch, citrate and nitrate, and were catalase and gelatinase positive, but indole, methyl red and Vogues Proskauer reaction negative. The organisms produced alkaline reaction on TSI agar slant. The acetylene reduction assay of the isolates at 0 and 1% NaCl in the culture media were 4.51-164.52 and 1.72-100.6 nmole C(2)H(4) ml(-1) culture media in 72 h, respectively. The isolates could fix 2.42-4.45 and 2.04-4.08 mg N(2) fixed 50 ml(-1) culture media at 0 and 1% NaCl in the culture media respectively. 16S rDNA sequences of the isolates were similar to the species: Bacillus sp. isolate 28A, Bacillus sp. MOLA 87, Bacillus sp. By113 (B)Ydz-dh, Bacillus sp. PN13, Bacillus licheniformis strain RH101, Bacterium Antarctica 14, Bacillus sp. PN13 and Bacillus megaterium.
- Evaluation of a novel biphasic culture medium for recovery of mycobacteria: a multi-center study. [Journal Article, Multicenter Study, Research Support, Non-U.S. Gov't]
- PLoS One 2012; 7(4):e36331.
Mycobacterial culture and identification provide a definitive diagnosis of TB. Culture on Löwenstein-Jensen (L-J) medium is invariably delayed because of the slow growth of M. tuberculosis on L-J slants. Automated liquid culture systems are expensive. A low-cost culturing medium capable of rapidly indicating the presence of mycobacteria is needed. The aim of this study was to develop and evaluate a novel biphasic culture medium for the recovery of mycobacteria from clinical sputum specimens from suspected pulmonary tuberculosis patients.The biphasic medium consisted of 7 ml units of L-J slant medium, 3 ml units of liquid culture medium, growth indicator and a mixture of antimicrobial agents. The decontamination sediments of sputum specimens were incubated in the biphasic culture medium at 37°C. Mycobacterial growth was determined based on the appearance of red granule sediments and the examination using acid-fast bacilli (AFB). The clinical sputum specimens were cultured in the biphasic medium, on L-J slants and in the Bactec MGIT 960 culture system. Among smear-positive specimens, the mycobacteria recovery rate of the biphasic medium was higher than that of the L-J slants (P<0.001) and similar to that of MGIT 960 (P>0.05). Among smear-negative specimens, the mycobacterial recovery rate of the biphasic medium was higher than that of L-J slants (P<0.001) and lower than that of MGIT 960 (P<0.05). The median times to detection of mycobacteria were 14 days, 20 days and 30 days for cultures grown in MGIT, in biphasic medium, on L-J slants for smear negative specimens, respectively (P<0.001).The biphasic culture medium developed in this study is low-cost and suitable for mycobacterial recovery. It does not require any expensive detection instrumentation, decreases the time required for detection of M. tuberculosis complex, and increases the detection rate of M. tuberculosis complex.
- Optimizing the growth of stressed Helicobacter pylori. [Evaluation Studies, Journal Article, Research Support, N.I.H., Extramural, Research Support, U.S. Gov't, Non-P.H.S.]
- J Microbiol Methods 2011 Feb; 84(2):174-82.
Helicobacter pylori is a gram-negative bacterium that colonizes the human stomach and is responsible for causing gastric ulcers. H. pylori is known to become stressed and nonculturable after exposure to unfavorable conditions. In this study, we enhanced previously published resuscitation procedures, characterized conditions under which stressed H. pylori can be recovered, and formulated a selective and differential resuscitation medium. Results showed that a specialized broth supplemented with trace minerals and lysed human erythrocytes and serum is required for the recovery of nonculturable H. pylori. The type of stress was an important factor in the efficacy of resuscitation, with cells exposed to atmospheric oxygen more readily resuscitated than nutrient deprived cells. After resuscitation, culturable cells were recovered from previously nonculturable oxygen stressed cells (24 and 72 h of exposure) and nonculturable nutrient deprived cells (24 h of exposure). The length of time the cells were exposed to the stress was also an important factor in the recovery of stressed H. pylori. RNA levels were quantified and transcription of the cell division related gene, cdrA (HP0066), was assessed by qRT-PCR. The low levels of RNA detected in stressed cells, after resuscitation, support the idea that a small population of viable cells may be responsible for the colonies recovered on solid agar. The modification of the resuscitation broth into a selective and differential slant culture medium also allowed the recovery of stressed H. pylori. The methods presented here highlight the benefits and limitations of using human blood products for recovering nonculturable H. pylori.
- Uncommon characteristics of the structure and development of Trichosporon asahii. [Journal Article, Research Support, Non-U.S. Gov't]
- Chin Med J (Engl) 2009 Aug 5; 122(15):1806-10.
Trichosporon asahii (T. asahii) is one of the most important pathogenic fungus in the genus of trichosporon. Although the species identification of T. asahii was based upon the complicated results of morphologic, biochemical and biologic examination, the morphology characteristic is still the first clue to the species. Some common structures of T. asahii had been described such as arthrofilaments and arthroconidia, but other important structures of T. asahii were unclear.Six strains of T. asahii were incubated on the slant and micro culture of Sabouraud's dextrose agar at 30 degrees C for 7 days. Samples were fixed using 2% paraformaldehyde and 2.5% glutaraldehyde. T. asahii was observed under scanning electron microscope and transmission electron microscope.The detailed characteristics of the diverse sites of germination, as well as some uncommon structures such as giant cell, sarcinate, and club-shaped macroconidia, were presented. The pseudohyphae of T. asahii were noted to produce true hyphae, either along the longitude axis or on the flank. T. asahii was noted to have blastic and thallic conidiation. Digitated branches, trichoid structures and septa inside the spores were detected.These results may add our knowledge to the structure and development of T. asahii.
- [A case of catheter-related bacteremia of Tsukamurella pulmonis]. [Case Reports, English Abstract, Journal Article]
- Korean J Lab Med 2009 Feb; 29(1):41-7.
Tsukamurella pulmonis is an aerobic actinomycete. We report a catheter-related bacteremia of T. pulmonis. A 39 yr-old male with ALL was hospitalized to receive bone marrow transplantation (BMT). Although the patient developed a high fever at the 7th hospital day (HD), it subsided with vancomycin treatment, and he received BMT at 9th HD. Fever resurged at 16th HD despite sustained treatment with vancomycin, meropenem, and amphotericin B, but subsided with removal of Hickman catheter (HC) at 19th HD. Three sets of blood cultures comprising one from the HC and two from venipunctures were taken at 7th, 16th, and 19th HD, and the distal tip of the HC was also cultured. The aerobic vials of all 3 HC-withdrawn blood cultures and one peripheral blood culture taken at 19HD and the HC tip culture grew long, straight, thin gram-positive rods that were positive on modified Kinyoun stain. This organism showed tiny, rough, grey colonies after 3-day incubation and grew to large flat colonies when incubation was extended. It was catalase-positive, urease-positive, and alkaline-slant/alkaline-deep on triple sugar iron agar, and hydrolyzed hypoxanthine. The sequence of 1,296 base pairs of 16S rRNA of this organism showed a 100.0% homology with the published sequence of T. pulmonis DSM 44142T. To our knowledge, this is the first report of T. pulmonis bacteremia in Korea.
- Unreliable detection of Mycobacterium xenopi by the nonradiometric Bactec MGIT 960 culture system. [Evaluation Studies, Journal Article]
- J Clin Microbiol 2009 Mar; 47(3):804-6.
From June 2006 to December 2007, 3,648 clinical specimens consecutively received for mycobacterial culture were investigated. Each processed sample was inoculated into Bactec MGIT 960 liquid medium and a Löwenstein-Jensen slant. Tubes that were flagged as positive by the instrument as well as those determined to be negative after 42 days of incubation were removed, visually inspected for growth, and checked for the presence of acid-fast bacilli. Three hundred sixty-nine mycobacterial strains were recovered; of the 44 Mycobacterium xenopi isolates recovered by MGIT medium, only 13 were detected by the instrument (P<0.0001). Most tubes yielding M. xenopi exhibited a peculiar pattern of growth characterized by a scant number of round, yellow-pigmented granules instead of the fine, evenly dispersed clumps usually observed for mycobacteria. It is suggested to check all individual tubes discarded by the MGIT 960 system at the end of the incubation period to prevent a significant amount of previously undetected growth from being missed.
- A new medium for diagnosis of dermatophyte infection. [Comparative Study, Journal Article, Research Support, Non-U.S. Gov't]
- Eur J Dermatol 2009 Jan-Feb; 19(1):34-7.
A new medium (DBM) was compared with dermatophyte test medium (DTM) for the diagnosis of dermatophyte infection. The sensitivity was 103 cfu/mL (2 x 101 cfu/slant) for both DTM and DBM with a suspension of Trichophyton rubrum. In axenic cultures, all dermatophytes tested altered the color of both media. Although most non dermatophytic molds made a color change, it was at a slower rate. In nail samples of dermatophyte infection, all dermatophytes altered the color of both media. However, the time for discoloration was shorter with DBM than with DTM (5.83 +/- 0.39 days vs. 7.32 +/- 0.41 days, t = 2.63, P = 0.01). Most isolates of nondermatophyte also made a discoloration, but they could be distinguished from dermatophytes by their colonial diameters when the color began to change (> or = 5 mm). Our results were in good agreement with a professional laboratory of medical mycology, however, the latter is regularly able to differentiate exactly the species of the growing dermatophyte. The DBM medium is more convenient, rapid, more accurate and economical to use than DTM.
- Trends in news coverage about skin cancer prevention, 1993-2006: increasingly mixed messages for the public. [Journal Article, Research Support, Non-U.S. Gov't]
- Aust N Z J Public Health 2008 Oct; 32(5):461-6.
To provide a comprehensive overview of trends in news coverage about sun protection issues in an Australian setting over a 14-year period.A content analysis was performed on all relevant articles (N=547) published in two major daily newspapers, The Age and the Herald Sun, from 1993 to 2006. Articles were coded for article type, prominence, theme, spokesperson, topic slant and opinion slant.The most frequent themes were the health effects of ultraviolet (UV) radiation exposure (24% of articles), education/prevention (14%) and product issues (12%). Themes that became more dominant over time were vitamin D issues, solaria issues and fake tans. Sixty per cent of articles included a pro-sun protection spokesperson and 12% an anti-sun protection spokesperson, with the profile of anti-sun protection spokespeople increasing over time. Half the articles reported on topics positive for sun protection, whereas 18% reported on negative topics; however, this difference narrowed considerably from 2001 onwards. In opinionated articles, the opinions expressed by authors were mainly positive (57%) rather than negative (7%) for sun protection.The findings suggest that the mix of sun protection issues covered and views of sun protection have changed over time, resulting in greater coverage of controversies and issues not necessarily positive for sun protection objectives. These findings imply that evaluation of paid skin cancer prevention public education campaigns may need to take account of the changing news media environment in which they take place.