Recovery of Streptococci from a Variety of Foods: A Comparison of Several Media1

1975 ◽  
Vol 38 (6) ◽  
pp. 323-326 ◽  
Author(s):  
J. L. OBLINGER
Keyword(s):  
Food Samples ◽  
Blood Agar ◽  
Selective Media ◽  
Solid Media ◽  
Ethyl Violet

Nine liquid and solid media used to isolate and/or enumerate streptococci were evaluated using 30 food samples. Streptococci were recovered from all of the samples surveyed. Azide Blood agar gave the highest recovery of streptococci and also allowed the observation of hemolytic reactions. Streptosel, KF streptococcus, and m-Enterococcus agars were also used, with the latter giving the lowest recovery among the agars. Azide Dextrose, KF, and Streptosel broths gave similar recoveries from most samples. Confirmation of Azide Dextrose isolates in Ethyl Violet Azide broth lowered streptococcal estimates by several log cycles. When isolates from both agar and broth cultures were subjected to further testing. Lactobacillus and Staphylococcus were often encountered, thus indicating the need to confirm representative numbers of colonies even if they are from selective media.

scholarly journals Influence of local tetracycline on the microbiota of alveolar osteitis in rats

2008 ◽  
Vol 19 (2) ◽  
pp. 119-123 ◽  
Author(s):  
Joseane Maria Dias Bosco ◽  
Sérgio Ricardo de Oliveira ◽  
Álvaro Francisco Bosco ◽  
Christiane Marie Schweitzer ◽  
Elerson Gaetti Jardim Júnior
Keyword(s):  
Aqueous Solution ◽  
Wistar Rats ◽  
Blood Agar ◽  
Selective Media ◽  
Sterile Saline ◽  
Alveolar Osteitis ◽  
Microbial Samples

The aim of the present study was to evaluate the effects of local tetracycline on the occurrence of alveolar osteitis in rats, and on the microbiota associated to this infection. Forty Wistar rats were randomly assigned to 4 groups (n=10): I - the rats had the maxillary right incisor extracted and the alveolar wound did not receive any treatment; II - adrenaline and Ringer-PRAS were introduced into the alveolar wound; III - the alveolar wound was irrigated with sterile saline; and IV - the alveolar wound was irrigated with an aqueous solution of tetracycline. Microbial samples from the alveolar wounds were collected 2 days after surgery and inoculated on blood agar (with and without 8 µg/mL of tetracycline) and other selective media, and were incubated in either aerobiosis or anaerobiosis at 37ºC, for 2 to 14 days. It was verified that tetracycline reduced the occurrence of alveolar osteitis in the rats and caused significant changes in the microbiota of the surgical sites, decreasing the number of anaerobes and increasing the participation of tetracycline-resistant and multi-resistant microorganisms.

A Comparison of Six Selective Media for the Enumeration and Isolation of Staphylococci1

1988 ◽  
Vol 51 (9) ◽  
pp. 685-690 ◽  
Author(s):  
D. G. WHITE ◽  
J. S. MATOS ◽  
R. J. HARMON ◽  
B. E. LANGLOIS
Keyword(s):  
Blood Agar ◽  
Control Medium ◽  
Bovine Blood ◽  
Mannitol Salt Agar ◽  
Selective Media ◽  
Specific Medium

The efficacy of Baird-Parker agar, Baird-Parker agar with bacitracin (0.8 μg/ml), Baird-Parker agar supplemented with acriflavin (7 μg/ml), polymyxin (20 units/ml) and sulphonamides (55 μg/ml), KRANEP agar, mannitol salt agar, and Staphylococcus medium 110 agar for the isolation and enumeration of Staphylococcus species was investigated. Bovine blood agar was used as the control medium. Thirty-seven staphylococci strains representing 23 species and 19 non-Staphylococcus species were tested. None of the six selective media supported the growth of all 37 Staphylococcus strains. The number of Staphylococcus species that grew on a specific medium ranged from only the S. aureus strains on Baird-Parker agar supplemented with acriflavin, polymyxin, and sulphonamides, to all but S. warneri BG 647 on Staphylococcus medium 110 agar. Strains of Bacillus, Corynebacterium, and Micrococcus grew on all six selective media.

Methods for Recovery of Campylobacter jejuni from Foods

1982 ◽  
Vol 45 (14) ◽  
pp. 1332-1337 ◽  
Author(s):  
NORMAN J. STERN
Keyword(s):  
Campylobacter Jejuni ◽  
Gas Flow ◽  
Raw Milk ◽  
Growth Conditions ◽  
Food Samples ◽  
Human Infection ◽  
Animal Products ◽  
Enrichment Broth ◽  
Selective Media ◽  
Sensitivity And Selectivity

The triangular relationship between Campylobacter jejuni, foods and disease in humans has been well-documented. Many studies have revealed that C. jejuni causes at least as many cases of human gastroenteritis as does Salmonella sp. Foods are an important vehicle in human infection, and raw milk is most frequently implicated. Other animal products also serve as potential sources of infection. C. jejuni has been found on the carcasses of poultry and other domestic animals throughout the world. The organism is microaerophilic and various methods for establishing appropriate growth conditions, such as the Fortner principle, atmosphere replacement and adding of supplements to encourage growth of C. jejuni, are available. Methods developed for use in clinical laboratories lack the necessary sensitivity and selectivity, and therefore have limited use in detecting small numbers of C. jejuni in foods. In one enrichment method for detecting C. jejuni in foods, washings are filtered and centrifuged, the sediment is suspended in the enrichment broth and the suspension is incubated under a constant gas flow at reduced oxygen levels. Following incubation enrichment broth is filtered and plated onto selective media. In another recently developed method, food samples are directly added to an enrichment broth with antibiotics and incubated under a microaerobic atmosphere before selective plating. Butzler's, Skirrow's and Campy-BAP selective media use several antibiotics to which C. jejuni is resistant. The plates are supplemented with horse or sheep blood, depending upon the specific formulation. The optimum temperature for growth of C. jejuni, about 42°C, may also be used for selection. It is now possible to recover 0.1 to 1 cell of C. jejuni per 10 to 25 g of food sample from among 106 to 109 indigenous bacteria. After a characteristic colony is isolated, the key criteria for presumptive identification of C. jejuni by phase-contrast microscopy are darting, corkscrew motion and a comma to spiral shape.

scholarly journals DETECTION OF HBLD TOXIN GENE BY BACILLUS CEREUS ISOLATED FROM MEAT CURRY FOOD SAMPLES IN MALAYSIAN RESTAURANTS

2020 ◽  
Vol 4 (2) ◽  
pp. 68-72
Author(s):  
Marwan Msarah ◽  
Ahmed Alsier ◽  
Sahilah, A.M.
Keyword(s):  
Bacillus Cereus ◽  
Foodborne Pathogen ◽  
Food Poisoning ◽  
Egg Yolk ◽  
Food Samples ◽  
Blood Agar ◽  
Toxin Gene ◽  
Biochemical Tests ◽  
Isolation Medium ◽  
Hemolysin Bl

Bacillus cereus is a ubiquitous foodborne pathogen, can cause food poisoning, leading to infections, have two major types of food poisoning emetic and diarrheal. Foods rich in protein such as meat are associated with foodborne outbreaks of diarrhea caused by B. cereus. The aim of this study is to isolate and identify B. cereus from ready to eat (RTE) meat curry from restaurants in Malaysia and to detect hblD pathogenic gene of B. cereus isolates. Mannitol egg yolk polymyxin agar was used as a selective isolation medium. Commercially available kits and boiling methods were used for DNA extraction, samples acquired from restaurants were examined for the presence of Hemolysin BL gene by polymerase chain reaction (PCR). Among all isolates, twenty-four of B. cereus isolates detected for HBL enterotoxin production by the discontinuous pattern on HBL sheep blood agar then confirmed by biochemical tests. More than 58.33 % of the isolate showed discontinuous hemolysis pattern on HBl blood agar and 29.16% of the samples were shown positive for hblD gene that can cause diarrhea with the size of 807bp on gel. This study demonstrated that RTE meat curry was a potential source for entero-toxigenic B. cereus and the presence of the hblD toxin genes for the HBL complex in the isolates tested were highly associated. Therefore, these meat curry isolates should be regarded as potential toxin producers.

Total Viable Count of Microorganisms in the Infected Dental Pulp

1974 ◽  
Vol 53 (6) ◽  
pp. 1330-1333 ◽  
Author(s):  
E.S. Akpata
Keyword(s):  
Root Canal ◽  
Dental Pulp ◽  
Viable Count ◽  
Tomato Juice ◽  
Blood Agar ◽  
Total Viable Count ◽  
Solid Media

A technique for estimating the total viable count of microorganisms in the infected dental pulp is described. The count obtainable using blood agar, tomato juice agar, or Sabouraud's agar solid media is about 106 per tooth. Anaerobes are more numerous than aerobes counted on the blood agar plates. It may be possible to apply this technique for evaluating the efficacy of root canal dressings.

Comparison of Three Selective Media and Validation of the VIDAS Campylobacter Assay for the Detection of Campylobacter jejuni in Ground Beef and Fresh-Cut Vegetables

2011 ◽  
Vol 74 (3) ◽  
pp. 456-460 ◽  
Author(s):  
JUNG-WHAN CHON ◽  
JI-YEON HYEON ◽  
IN-SOO CHOI ◽  
CHAN-KYU PARK ◽  
SOO-KI KIM ◽  
...  
Keyword(s):  
Campylobacter Jejuni ◽  
Ground Beef ◽  
Food Samples ◽  
Assay Method ◽  
Enzyme Linked Immunosorbent Assay ◽  
Culture Methods ◽  
Selective Media ◽  
Fresh Cut ◽  
Microaerobic Conditions ◽  
Campylobacter Spp

In this study, three different selective media, modified cefoperazone charcoal deoxycholate agar (mCCDA), Karmali agar, and Preston agar, were compared for isolating Campylobacter jejuni from artificially contaminated ground beef and fresh-cut vegetables that have different levels of background microflora. Concurrently, an automated enzyme-linked immunosorbent assay method for detecting Campylobacter spp. (VIDAS Campylobacter) was evaluated by comparing it with the culture methods. Food samples inoculated with C. jejuni were enriched in Bolton broth at 42°C for 44 h and then streaked onto the three different selective media, followed by incubation under microaerobic conditions at 42°C for 48 h. The enriched Bolton broth (1 ml) was used in the VIDAS Campylobacter assay. No statistical differences in sensitivities were observed between the three selective media for ground beef and fresh-cut vegetables, but the selectivity of Preston agar was better (P < 0.05) than those of mCCDA and Karmali agar. The VIDAS Campylobacter assay showed a recovery rate similar (P > 0.05) to those of all of the medium combinations in ground beef. However, more positive samples (P < 0.05) were detected with the VIDAS Campylobacter than with the selective agars, except for the combinations of mCCDA plus Preston agar or mCCDA plus Karmali agar plus Preston agar in fresh-cut vegetables.

Enumeration of Sublethally Injured Escherichia coli O157:H7 ATCC 43895 and Escherichia coli Strain B-41560 Using Selective Agar Overlays versus Commercial Methods

2013 ◽  
Vol 76 (4) ◽  
pp. 674-679 ◽  
Author(s):  
AMANDA R. SMITH ◽  
ALYSHA L. ELLISON ◽  
AMANDA L. ROBINSON ◽  
MARYANNE DRAKE ◽  
SUSAN A. McDOWELL ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Ground Beef ◽  
Food Samples ◽  
Coli Strain ◽  
Milk Formula ◽  
Selective Media ◽  
E Coli ◽  
Infant Milk Formula ◽  
Intervention Measures ◽  
Direct Inoculation

Quality control procedures during food processing may involve direct inoculation of food samples onto appropriate selective media for subsequent enumeration. However, sublethally injured bacteria often fail to grow, enabling them to evade detection and intervention measures and ultimately threaten the health of consumers. This study compares traditional selective and nonselective agar-based overlays versus two commercial systems (Petrifilm and Easygel) for recovery of injured E. coli B-41560 and O157:H7 strains. Bacteria were propagated in tryptic soy broth (TSB), ground beef slurry, and infant milk formula to a density of 106 to 108 CFU/ml and then were stressed for 6 min either in lactic acid (pH 4.5) or heat shocked for 3 min at 60°C. Samples were pour plated in basal layers of either tryptic soy agar (TSA), sorbitol MacConkey agar (SMAC), or violet red bile agar (VRB) and were resuscitated for 4 h prior to addition of agar overlays. Other stressed bacteria were plated directly onto Petrifilm and Easygel. Results indicate that selective and nonselective agar overlays recovered significantly higher numbers (greater than 1 log) of acid-and heat-injured E. coli O157:H7 from TSB, ground beef, and infant milk formula compared with direct plating onto selective media, Petrifilm, or Easygel, while no significant differences among these media combinations were observed for stressed E. coli B-41560. Nonstressed bacteria from TSB and ground beef were also recovered at densities significantly higher in nonselective TSA-TSA and in VRB-VRB and SMAC-SMAC compared with Petrifilm and Easygel. These data underscore the need to implement food safety measures that address sublethally injured pathogens such as E. coli O157:H7 in order to avoid underestimation of true densities for target pathogens.

scholarly journals Growth of Streptococcus mutans on various selective media

1976 ◽  
Vol 4 (1) ◽  
pp. 95-98
Author(s):  
C G Emilson ◽  
D Bratthall
Keyword(s):  
Streptococcus Mutans ◽  
Growth Phase ◽  
Blood Agar ◽  
Similar Data ◽  
Logarithmic Growth Phase ◽  
Batch Cultures ◽  
Selective Media ◽  
Serotype A ◽  
Colony Forming Units ◽  
Logarithmic Growth

The ability of Streptococcus mutans to grow on mitis-salivarius (MS) agar, MC agar, mitis-sucrose-bacitracin (MSB), BCY agar, and MM10 sucrose agar was studied. Batch cultures of S. mutans serotype a demonstrated no growth on MSB agar. Certain serotype d and g strains did not grow on MC agar. The yield for most strains of other serotypes on these selective media was lower compared with that on MS agar. The number of total colony-forming units on BCY and MM10 sucrose agar was similar to the blood agar results. Similar data were obtained when fermenter-grown strains, harvested in the middle or the end of the logarithmic growth phase, were used for inoculation of the various media. Enumeration of S. mutans from plaque samples plated on MC and MSB agar yielded about 75% of the counts obtained on MS or the nonselective medium. When the proportions of S. mutans were expressed as a percentage of the total cultivable flora, the selective media (MC and MSB agar) showed approximately 10% lower values than the MS, BCY, and MM10 sucrose agar.

scholarly journals A comparison of procedures for the isolation of campylobacters from seagull faeces

1983 ◽  
Vol 91 (3) ◽  
pp. 445-450 ◽  
Author(s):  
C. R. Fricker ◽  
R. W. A. Girdwood ◽  
D. Munro
Keyword(s):  
The Other ◽  
Campylobacter Coli ◽  
Direct Plating ◽  
Selective Media ◽  
Solid Media ◽  
Fluid Media

SUMMARYTwo enrichment broths (Preston and Roman & Doyle's) and four solid media (Preston, Skirrow's, Butzler's and Blaser's) were compared to determine their relative efficiencies in recovering campylobacters from 389 freshly voided seagull faeces, 276 of which were found to contain campylobacters by one or more of the procedures used.A combination of enrichment in Preston medium followed by plating on to Preston agar gave the highest number of isolates (263). Enrichment in fluid media was shown to be an important part of the technique, as only 85 (30·8 %) of the 276 isolations were made as a result of direct plating.Very little difference was seen between the two forms of enrichment (P> 0·5) but of the four selective media, Butzler's was significantly less efficient than any of the other three (P< 0·01), because it failed to grow more than a few strains ofCampylobacter coliand the NARTC group, which together made up nearly two-thirds of the total number ofCampylobacterspp. isolated.

scholarly journals The effect of the use of different selective media on the ability to recover salmonellae from seagull faeces

1984 ◽  
Vol 93 (1) ◽  
pp. 35-42 ◽  
Author(s):  
C. R. Fricker ◽  
R. W. A. Girdwood
Keyword(s):  
Brilliant Green ◽  
Salmonella Typhi ◽  
Effective Medium ◽  
Selective Media ◽  
Faecal Material ◽  
Solid Media ◽  
Wide Range ◽  
Peptone Water ◽  
The Media ◽  
Salmonella Serotypes

SUMMARYSolid media were compared for their ability to recover salmonellae from seagull faecal material after pro-enrichment in buffered peptone water and enrichment in Rappaport's broth. Of the 847 specimens examined 96 were found to be positive for salmonellae. Use of Brilliant Green agar containing sulphamandelate supplement resulted in the detection of salmonellae from each of the 96 samples found to be positive and was the most efficient medium tested. Brilliant Green agar lacking the supplement was the least effective medium, salmonellae being isolated from only 80 samples using this medium.All of the media tested were shown to support the growth of a wide range of salmonella serotypes, althoughSalmonella typhiandS. dublindid not form colonies on those media which contained Brilliant Green. Hynes' modification of deoxycholate citrate agar was shown to be considerably less inhibitory to salmonellae after ageing for four days. Ageing of other media had no significant affect on their ability to support the growth of salmonellae.

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