Study of growth, metabolism, and morphology of Akkermansia muciniphila with an in vitro advanced bionic intestinal reactor.

BACKGROUND: As a kind of potential probiotic, Akkermansia muciniphila abundance in human body is directly causally related to obesity, diabetes, inflammation and abnormal metabolism. In this study, A. muciniphila dynamic cultures using five different media were implemented in an in vitro bionic intestinal reactor for the first time instead of the traditional static culture using brain heart infusion broth (BHI) or BHI + porcine mucin (BPM). RESULTS: The biomass under dynamic culture using BPM reached 1.92 g/L, which improved 44.36% compared with the value under static culture using BPM. The biomass under dynamic culture using human mucin (HM) further increased to the highest level of 2.89 g/L. Under dynamic culture using porcine mucin (PM) and HM, the main metabolites were short-chain fatty acids (acetic acid and butyric acid), while using other media, a considerable amount of branched-chain fatty acids (isobutyric and isovaleric acids) were produced. Under dynamic culture Using HM, the cell diameters reached 999 nm, and the outer membrane protein concentration reached the highest level of 26.26 µg/mg. CONCLUSIONS: This study provided a preliminary theoretical basis for the development of A. muciniphila as the next generation probiotic.

Growth of MRSA and Pseudomonas aeruginosa in a fine-celled foam model containing sessile commensal skin bacteria.

Sessile cultures of the skin bacteria Staphylococcus saprophyticus and Corynebacterium xerosis were grown using novel fine-celled foam substrata to test the outcome of challenge by methicillin-resistant Staphylococcus aureus or Pseudomonas aeruginosa under three growth medium regimens (simulated sweat, simulated serum or simulated sweat substituted with simulated serum during the microbial challenge). S. saprophyticus and C. xerosis significantly limited MRSA and P. aeruginosa immigration respectively, under the simulated sweat and serum medium regimes. Under the substitution medium regime however, MRSA and P. aeruginosa integrated into pre-established biofilms to a significantly greater extent, attaining cell densities similar to the axenic controls. The outcome of challenge was influenced by the medium composition and test organism but could not be predicted based on planktonic competition assays or growth dynamics. Interactions between skin and wound isolates could be modelled using the fine-celled foam-based system. This model could be used to further investigate interactions and also in preclinical studies of antimicrobial wound care regimens.

Impact of Implementation of an Automated Liquid Culture System on Diagnosis of Tuberculous Pleurisy.

This study was conducted to evaluate the impact of implementation of an automated liquid culture system on the diagnosis of tuberculous pleurisy in an HIV-uninfected patient population. We retrospectively compared the culture yield, time to positivity, and contamination rate of pleural effusion samples in the BACTEC Mycobacteria Growth Indicator Tube 960 (MGIT) and Ogawa media among patients with tuberculous pleurisy. Out of 104 effusion samples, 43 (41.3%) were culture positive on either the MGIT or the Ogawa media. The culture yield of MGIT was higher (40.4%, 42/104) than that of Ogawa media (18.3%, 19/104) (P<0.001). One of the samples was positive only on the Ogawa medium. The median time to positivity was faster in the MGIT (18 days, range 8-32 days) than in the Ogawa media (37 days, range 20-59 days) (P<0.001). No contamination or growth of nontuberculous mycobacterium was observed on either of the culture media. In conclusion, the automated liquid culture system could provide approximately twice as high yields and fast results in effusion culture, compared to solid media. Supplemental solid media may have a limited impact on maximizing sensitivity in effusion culture; however, further studies are required.

[An alternative biphasic nutrient medium for the diagnosis of cutaneous leishmaniasis]. / Kutanöz leysmanyazis tanisinda alternatif bifazik nutrient besiyeri.

Cutaneous leishmaniasis (CL) caused by the Leishmania spp. parasites, is a disease characterized by nodulo-ulcerative lesions in the skin. CL is transmitted to humans by infected sandflies during blood sucking, and is endemic in about 98 countries over the world. The demonstration of amastigotes via microscopic examination, and the growth of promastigotes in NNN (Novy-MacNeal-Nicolle) medium are gold standard methods for laboratory diagnosis. The aim of this study was to compare the biphasic NNN medium that is frequently used in routine laboratories with the biphasic nutrient medium that can be prepared easily in microbiology laboratories, for the growth of promastigotes. In the study, the aspiration fluid sample was used as clinical sample which was obtained from the skin lesion of a 47-year-old female patient admitted to Izmir Katip Celebi Ataturk Education and Research Hospital dermatology outpatient clinic and pre-diagnosed as CL. The aspirate sample taken from the lesion was evaluated with microscopy, cultivation in two different media and real-time polymerase chain reaction (Rt-PCR) methods. In microscopic examination Leishmania amastigotes were observed in Giemsa-stained smears prepared from the aspiration fluid. In Rt-PCR performed by using specific primers and probes targeting ITS1 region of Leishmania parasite, a melting-curve compatible with L.tropica was detected. For cultivation, triple inoculations of the aspirate sample into NNN (NNN + RPMI 1640 + 10% fetal calf serum) and nutrient media (nutrient agar + nutrient broth + 10% fetal calf serum) were used. The cultures were incubated at 27°C for 10 days, and the number of propagated promastigotes were counted on the third, seventh and tenth days. The growth of Leishmania promastigotes was detected in both media on the third day. The number of promastigotes grown in NNN medium on the third, seventh and tenth days were 105/ml, 106/ml and 108/ml, respectively. Those values in nutrient medium were 106/ml, 107/ml and 108/ml on the third, seventh and tenth days, respectively. Although the number of promastigotes on the third and seventh days were higher in nutrient medium than NNN medium, the number of cultivated promastigotes were equal on the tenth day. As a result, nutrient medium is considered to have an impact in the diagnosis of CL, by providing an alternative to the routine medium used and can readily be available in microbiology and parasitology laboratories with long shelf-life. It was concluded that biphasic nutrient medium could be used as a supplementary medium for diagnosis in laboratories in the absence of NNN medium or can not be provided.

[Evaluation of second-line antituberculosis drug susceptibilities of multidrug-resistant Mycobacterium tuberculosis complex isolates by E-test method]. / Çok ilaca dirençli Mycobacterium tuberculosis kompleks izolatlarinda ikinci basamak antitüberküloz ilaç duyarliliklarinin E-test yöntemi ile degerlendirilmesi.

Multidrug-resistant (MDR) tuberculosis (TB) constitutes a restricting factor for the effective treatment of TB worldwide. Early diagnosis and appropriate treatment of patients are the most effective strategy in the control of MDR-TB. Therefore, knowledge of drug resistance patterns of the MDR-TB clinical isolates are necessary in planning of an appropriate treatment regimen for the patient. The aims of this study were to detect the susceptibilities of MDR-TB isolates to second-line anti-TB drugs by E-test method, and to compare their results with Löwenstein-Jensen (LJ) proportion method. A total of 122 MDR (resistant to isoniazid and rifampicin) Mycobacterium tuberculosis complex (MTC) strains isolated from samples of patients with pulmonary TB were included in the study. The isolates were identified by conventional methods and first-line anti-TB drug susceptibility testing was performed by the proportion method using LJ medium. The susceptibilities of the isolates to second-line anti-TB drugs [kanamycin (KN), ofloxacin (OFL), ethionamid (ETN), linezolid (LIN)] were tested by proportion method on LJ medium and E-test method on Middlebrook 7H11 medium. For this purpose, E-test strips (bioMerieux, Fransa) of KN (0.016-256 mg/ml), OFL (0.02-32 mg/ml), ETN (0.016-256 mg/ml), and LIN (0.016-256 mg/ml) were used. The susceptibility tests were evaluated in 5., 7., and 10. days after application of the E-test strips, and proportion method on LJ medium was evaluated 28 days later. Second line-anti-TB drug susceptibility results were obtained in 5 to 10 days by E-test. Of the MDR MTC strains 98% (119/122) were susceptible to KN, OFL and LIN, while 2% (3/122) of the strains were resistant to KN and ETN. The correlation between E-test and LJ proportion method was estimated as 96% for KN and ETN, 98% for OFL, and 100% for LIN. When compared with LJ proportion method, the specificity of E-test in the detection of susceptibility to KN, OFL, ETN and LIN were 60%, 38%, 60%, and 100%, respectively, while the sensitivity was 100% for all drugs. Our results indicated that E-test method exhibited high sensitivity and specificity (100%) for LIN, so it may be used alone in susceptibility testing for this drug, however since the specificity is low (38%) for OFL it should be used together with the proportion method. In conclusion, E-test method might contribute for initiation of an early and effective anti-TB drug treatment and control of infection by rapid diagnosis in MDR-TB cases.

Evaluation of different culture media for improvement in bioinsecticides production by indigenous Bacillus thuringiensis and their application against larvae of Aedes aegypti.

Production of indigenous isolate Bacillus thuringiensis sv2 (Bt sv2) was checked on conventional and nonconventional carbon and nitrogen sources in shake flasks. The effects on the production of biomass, toxin production, and spore formation capability of mosquito toxic strain were determined. Toxicity differs within the same strain depending on the growth medium. Bt sv2 produced with pigeon pea and soya bean flour were found highly effective with LC50 < 4 ppm against larvae of Aedes aegypti. These results were comparable with bacteria produced from Luria broth as a reference medium. Cost-effective analyses have revealed that production of biopesticide from test media is highly economical. The cost of production of Bt sv2 with soya bean flour was significantly reduced by 23-fold. The use of nonconventional sources has yielded a new knowledge in this area as the process development aspects of biomass production have been neglected as an area of research. These studies are very important from the point of media optimization for economic production of Bacillus thuringiensis based insecticides in mosquito control programmes.

Evaluation of three selective media for isolation of Aggregatibacter actinomycetemcomitans.

BACKGROUND AND OBJECTIVE: Aggregatibacter actinomycetemcomitans is a pathogen in oral and nonoral infections. Detection and quantification of this pathogen can be performed using selective culture techniques. The aim of this study was to establish the efficacy of two known selective media in their ability to select and support the growth of A. actinomycetemcomitans. MATERIAL AND METHODS: Trypticase soy bacitracin vancomycin (TSBV) medium and brain-heart infusion agar with vancomycin (Dentaid-1), as well as a modified Dentaid-1 medium (in which the brain-heart infusion agar was substituted with brain-heart infusion broth), were compared. Two-hundred and eighteen clinical samples were used to establish the recovery rate, the number of colony-forming units (CFUs) of A. actinomycetemcomitans as well as the total number of CFUs on the three different types of medium. In addition, the numbers of gram-negative aerobic rods and yeasts were determined. RESULTS: Both types of Dentaid-1 medium showed a higher recovery of A. actinomycetemcomitans compared with TSBV. However, these differences did not reach statistical significance. The total number of CFUs of A. actinomycetemcomitans recovered was significantly higher on Dentaid-1 compared with TSBV (p = 0.029). The mean number of gram-negative aerobic rods recovered was statistically higher on both types of Dentaid-1 medium in comparison with TSBV. Low numbers of yeasts were recovered occasionally on all test plates. CONCLUSION: Dentaid-1 is a low-cost effective alternative to TSBV for the isolation and growth of A. actinomycetemcomitans from clinical samples, such as dental plaque, which contain a complex microflora.

Modern principles of classification and development of nutrient media for culturing of human and animal cells.

Analysis of the main principles of classification and development of nutrient media used for culturing of human and animal cells in biology and medicine is presented. The key moments of induction and regulation of mitogenic cascades and their differences in cells of continuous lines, diploid cells, and primary cultures are discussed. Some variants of classification of nutrient media for various cell culture types are described. Peculiarities of composition and the prospects of using serum-free media are discussed. Practical results obtained by the authors in the development of diverse purpose nutrient media are presented.

Species composition of bacterial communities influences attraction of mosquitoes to experimental plant infusions.

In the container habitats of immature mosquitoes, catabolism of plant matter and other organic detritus by microbial organisms produces metabolites that mediate the oviposition behavior of Aedes aegypti and Aedes albopictus. Public health agencies commonly use oviposition traps containing plant infusions for monitoring populations of these mosquito species, which are global vectors of dengue viruses. In laboratory experiments, gravid females exhibited significantly diminished responses to experimental infusions made with sterilized white oak leaves, showing that attractive odorants were produced through microbial metabolic activity. We evaluated effects of infusion concentration and fermentation time on attraction of gravid females to infusions made from senescent bamboo or white oak leaves. We used plate counts of heterotrophic bacteria, total counts of 4',6-diamidino-2-phenylindole-stained bacterial cells, and 16S ribosomal DNA (rDNA) polymerase chain reaction-denaturing gradient gel electrophoresis (DGGE) to show that changes in the relative abundance of bacteria and the species composition of bacterial communities influenced attraction of gravid A. aegypti and A. albopictus mosquitoes to infusions. DGGE profiles showed that bacterial species composition in infusions changed over time. Principal components analysis indicated that oviposition responses to plant infusions were in general most affected by bacterial diversity and abundance. Analysis of bacterial 16S rDNA sequences derived from DGGE bands revealed that Proteobacteria (Alpha-, Beta-, Delta-, and Gamma-) were the predominant bacteria detected in both types of plant infusions. Gravid A. aegypti were significantly attracted to a mix of 14 bacterial species cultured from bamboo leaf infusion. The oviposition response of gravid mosquitoes to plant infusions is strongly influenced by abundance and diversity of bacterial species, which in turn is affected by plant species, leaf biomass, and fermentation time.

Assessment of the anti-listerial activity of microfloras from the surface of smear-ripened cheeses.

The anti-listerial activity of microfloras from the surface of various smear-ripened cheeses was evaluated using four methods that were then compared. Method A measured the anti-listerial potential of supernatants from short-time liquid cultures, whereas in Method B, a model cheese was co-inoculated with the microflora and Listeria innocua test strains. Method C was based on successive propagations of the microfloras on this model cheese, and Method D on successive propagations of the microfloras together with Listeria test strains. Anti-listerial activity considerably depended on the microflora used. Significant correlations were obtained between Methods A and B and Methods C and D. With Methods C and D, the highest anti-listerial activity was obtained with the microflora from a Livarot-type cheese (FC12). To investigate the cause of the anti-listerial activity of FC12, Fourier Transform InfraRed (FTIR) analyses of microbial populations were performed on the original microflora as well as on the microflora after propagations on the model cheese. The composition of FC12 had changed considerably upon propagation, and in the propagated microflora, the population of yeasts was dominated by Yarrowia lipolytica strains, whereas the population of bacteria was dominated by Vagococcus species.

Study of the lactic acid bacteria throughout the manufacture of dry-cured lacón (a Spanish traditional meat product). Effect of some additives.

Total aerobic mesophilic microflora (on SPC agar), lactic acid bacteria (on MRS agar) and lactobacilli (on Rogosa agar) were enumerated in samples from the surface and the interior of the pieces throughout the manufacture of six batches of lacón. Three of the batches were made without additives and three with additives (glucose (2 g/kg), sodium nitrite (E(250)) (125 mg/kg), sodium nitrate (E(251)) (175 mg/kg), sodium ascorbate (E(301)) (500 mg/kg), and sodium citrate (E(331)) (100 mg/kg)). The counts decreased throughout the manufacturing process, particularly after the salting stage. The use of additives did not affect the counts or the evolution of the microbial groups, except for the lactobacilli, which were present in higher numbers in the batches with additives. In four batches (two without and two with additives), from MRS agar and from Rogosa agar plates, 10 colonies were randomly taken from each sampling point of each batch (five from the surface sample and five from the interior sample) and from each culture medium; a total of 224 strains from MRS agar, and 176 strains from Rogosa agar that were identified by classical methods. The MRS agar displayed moderate selectivity for the isolation of lactic acid bacteria, and only 59% of the isolated strains belonged to this microbial group. Homofermentative and facultative heterofermentative lactobacilli (particularly Lactobacillus curvatus and Lactobacillus sakei) were the most abundant species isolated on this medium. The selectivity of the Rogosa agar for lactobacilli was extremely high. The species of lactobacilli isolated on this medium at different stages of manufacture of the four batches of lacón were consistent with those isolated from MRS agar. The use of additives in the lacón did not appreciably affect the kinds and proportions of species isolated on either MRS agar or Rogosa agar.

[Evaluation of biofilm formation by Staphylococcus aureus isolated from sputum of cystic fibrosis patients]. / Ocena tworzenia biofilmu przez szczepy Staphylococcus aureus wyizolowane z plwociny pacjentów z mukowiscydoza.

The purpose of this study was to evaluate two screening methods for detection of biofilm formation by eighty clinical Staphylococcus aureus isolates from patients with cystic fibrosis, and evaluation of biofilm production on the polystyrene 96-well tissue culture plates, depending on media applied. All clinical strains were incubated in three different media: Luria-Bertani broth (LB), tryptic soy broth supplemented with 2% glucose (TSBglu) and brain heart infusion (BHI). Biofilm production was screened by staining with crystal violet (CV) or with 2,3,5-triphenyltetrazolium chloride (TTC). Both CV and TTC assays showed, that all analyzed isolates created biofilm, in all tested media, however with different intensity. In conclusion, the CV method was found to be more sensitive than the TTC method, when we need information about whole mass of biofilm. The most optimal medium for the biofilm culture was LB medium.

Performance of MRSA ID chromogenic medium for detection of methicillin-resistant Staphylococcus aureus directly from blood cultures and clinical specimens.

MRSA ID was evaluated to see its performance in identifying methicillin-resistant Staphylococcus aureus (MRSA) directly from blood culture bottles (n = 837), wound swabs (n = 112), and abscesses (n = 18). Each positive blood culture and clinical specimen was directly inoculated on MRSA ID and the culture media routinely used. The sensitivity of MRSA ID was 97.8% after 24 h and 100% after 48 h for blood cultures, and 88.9% after 24 h and 100% after 48 h for wound samples. The specificity was 99.7% after 24 h and 99.6% after 48 h for blood cultures, and 100% after 24 and 48 h for wound samples. Four strains with green colonies indicating MRSA on MRSA ID were identified as methicillin-susceptible S. aureus (MSSA) by conventional methods. Three of these MSSA strains showed negative results with the mecA polymerase chain reaction, and 1 strain harbored the mecA gene. Using MRSA ID with primary culture media should decrease the time (18-24 h) to report a positive result compared with conventional methods.

Production and rheological characterization of biopolymer of Sphingomonas capsulata ATCC 14666 using conventional and industrial media.

This work was aimed at the production and rheological characterization of biopolymer by Sphingomonas capsulata ATCC 14666, using conventional and industrial media. The productivity reached the maximum of 0.038 g/L x h, at 208 rpm and 4% (w/v) of sucrose. For this condition, different concentrations of industrial medium were tested (2.66, 4, 6, and 8%). The best productivity was obtained using pretreated molasses 8% (w/v) (0.296 g/L x h), residue of textured soybean protein 6% (wt/v) (0.244 g/L x h) and crude molasses 8% (w/v) (0.192 g/L x h), respectively. Apparent viscosity presented similar results when compared with those in the literature for other biopolymers.

A descriptive study of culture media in Brazilian assisted reproduction clinics.

OBJECTIVE: The present study aimed to draw a profile of the most commonly used media and protocol characteristics from assisted reproduction technology (ART) facilities in Brazil. METHODS: To obtain an overview of ART methods and culture media, a questionnaire was given to embryologists from ART clinics in Brazil. Further research in scientific papers and journals was carried out for describing the processes around Brazil, USA and Europe. RESULTS: From the questionnaire, we found that the embryo medium mostly used is CSCMTM from Irvine Scientific, represented 37.04% in Brazilian ART clinics; interestingly, 70.37% of clinics exchange the embryo media bath; however, 70.37% do not change the media type. Transfers in Brazilian clinics were variable, but day 3 transfer was a procedure seen in 37.04%. The remaining embryos are habitually maintained in prolonged cultivation in 51.85% of the clinics interviewed. CONCLUSION: Although there are numerous studies trying to better understand embryo culture media influences, there is a lack of evidence for choosing one as the most appropriate. In short, it is a random decision for such an essential stage of In Vitro Fertilization.

Laboratory detection of Clostridium difficile. A comparison of media and incubation systems.

Parallel testing for culture recovery of Clostridium difficile was performed using three selective media in each of four anaerobic incubation environmental systems. Testing was completed on 67 stool samples from 60 hospitalized patients in whom C difficile-associated diarrhea was suspected. Three different media were evaluated: CCFA (modified cycloserine-cefoxitin-fructose agar), CCFA-PRAS (CCFA, prereduced-anaerobically-sterilized) and CMBA (modified cycloserine-mannitol-blood agar). The incubation systems compared were an anaerobic chamber (Model 800 Anaerobic Environmental System, Anaerobe Systems, San Jose, CA), the anaerobic jar (BBL, Cockeysville, MD), the anaerobic Bio-Bag (BBL), and the anaerobic pouch (BBL). C difficile was found in 16 samples collected from 15 patients. Comparing recovery on the various types of media in all four anaerobic atmospheres, C difficile was recovered on all (64) CCFA plates, 56 of 64 CCFA-PRAS plates, and 43 of 64 CMBA plates (P < .03 comparing CCFA and CMBA). Of the 48 plates in each incubation system that were inoculated with specimens positive for C difficile, the organism was recovered from 43 plates in the anaerobe chamber, 41 incubated in an anaerobe jar, 40 in the Bio-Bag, and 39 incubated in the GasPak pouch, all providing similar recovery of C difficile (P = .08). The CCFA-PRAS and CMBA media demonstrated less inhibition of normal stool flora compared to the CCFA. Overall CCFA that was anaerobically reduced at least 4 hours before use, and contained the original concentration of antimicrobial agents described by George and colleagues, was superior to CMBA for recovery of C. difficile.

Mycobacterium tuberculosis from chronic murine infections that grows in liquid but not on solid medium.

BACKGROUND: Old, stationary cultures of Mycobacterium tuberculosis contain a majority of bacteria that can grow in broth cultures but cannot grow on solid medium plates. These may be in a non-replicating, dormant growth phase. We hypothesised that a similar population might be present in chronic, murine tuberculosis. METHODS: Estimates of the numbers of viable M. tuberculosis, strain H37Rv, in the spleens and lungs of mice in a 7-day acute infection and in a 10-month chronic infection were made by conventional plate counts and, as broth counts, by noting presence or absence of growth in serial replicate dilutions in liquid medium. RESULTS: Plate and broth counts in 6 mice gave similar mean values in the acute infection, 7 days after infection. However, the broth counts were much higher in 36 mice with a chronic infection at 10 months. Broth counts averaged 5.290 log10 cfu /organ from spleens and 5.523 log10 cfu/organ from lungs, while plate counts were 3.858 log10 cfu/organ from spleens and 3.662 log10 cfu/organ from lungs, indicating that the total bacterial population contained only 3.7% bacilli in spleens and 1.4% bacilli in lungs, capable of growth on plates. CONCLUSION: The proportion growing on plates might be a measure of the "dormancy" of the bacilli equally applicable to cultural and animal models.