Spiral organisms in endoscopic biopsies of the human stomach.
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Bacteria↗
Biomedical subjects
C R Fricker
Publications and source records attributed to C R Fricker.
A comparison of methods for the isolation of salmonellae from sewage sludge.
Methods for the isolation of salmonellae from sewage sludge were compared. Buffered peptone water and lactose broth were compared to determine their efficiencies as preenrichment media and temperature and duration of incubation were also investigated. In addition five enrichment and five plating media were compared together with the effects of multiple plating of enrichment broths. Buffered peptone water incubated at 43 degrees C for 24 h was shown to be the pre-enrichment method of choice with enrichment in the RB 10 form of Rappaport's broth incubated at 43 degrees C for 48 h and plating at 24 and 48 h onto brilliant green agar containing sulphamandelate supplement and Hynes' modification of desoxycholate citrate agar. Of the 100 samples used in the study. 96 were found to be positive for salmonella by at least one of the procedures used. A total of 15 Salmonella serotypes were isolated. Salmonella virchow being the most common.
Bacteriological Techniques↗
Campylobacters in wading birds (Charadrii): incidence, biotypes and isolation techniques.
311 birds from four species of the charadrii group were examined for the carriage of Campylobacter spp. Cloacal swabs or "washouts" were taken from birds captured by cannon netting and cultured using enrichment in Preston broth followed by plating onto Preston agar. Incubation of enrichment cultures for 48 h and of solid media for a minimum of 48 h is recommended for culture of avian faecal material. Of the birds examined, 222 were found to be carrying Campylobacter spp., 145 strains of which belonged to the C. jejuni/C. coli group. Of the four species examined, Oystercatcher were significantly more frequently associated with the carriage of C. jejuni biotype 1 than were the other three species (P less than 0.05). The high carriage rate of Campylobacter spp. coupled with the behaviour of this group of birds may have implications for human health.
Animals↗
A comparison of enrichment media for the isolation of salmonellae from seagull cloacal swabs.
The relative efficiency of three selective enrichment broths (Muller-Kauffmann tetrathionate. Rappaport's and selenite F) was investigated for the isolation of salmonellae from seagull cloacal swabs. Pre-enrichment in buffered peptone water was employed throughout the study, which involved the examination of 560 gulls, sixty (10.7%) of which were found to be carrying salmonellae. Rappaport's broth as modified by Vassiliadis for incubation at 43 degrees C (Vassiliadis et al. 1976) yielded the highest number of positive swabs (57) and the widest range of serotypes. It was significantly more efficient that either selenite F or tetrathionate broth, although the results obtained with Rappaport's broth incubated at 37 and 43 degrees C did not differ significantly (P greater than 0.5). Eleven serotypes were isolated during the study, the most prevalent being Salmonella virchow.
Animals↗
A comparison of procedures for the isolation of campylobacters from seagull faeces.
Two 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 greater than 0.5) but of the four selective media, Butzler's was significantly less efficient than any of the other three (P less than 0.01), because it failed to grow more than a few strains of Campylobacter coli and the NARTC group, which together made up nearly two-thirds of the total number od Campylobacter spp. isolated.
Agar↗
Inter-laboratory comparison of the CD-1 neonatal mouse logistic dose-response model for Cryptosporidium parvum oocysts.
cryptosporidium parvum oocyst viability can be determined by vital dyes, in vitro excystation, and cell culture; however, neonatal mouse infectivity assays are the reference method. Unfortunately, there have been few efforts to standardize methods for infectivity assays thus casting a veil of uncertainty over the significance and comparability of results. In order to address this issue, two laboratories proficient in measuring oocyst infectivity conducted independent dose titration studies with neonatal CD-1 mice using standardized protocols and a well-characterized isolate of Cryptosporidium parvum. The resulting independent logistic dose-response models derived by regression analysis were compared with each other and with a published model. The comparisons showed these dose-response functions to be reproducible under standardized conditions. It is important to standardize mouse strain, age of mice at inoculation and necropsy, oocyst isolate, and age of oocysts. However, other factors, including methods used to detect infectivity and to count oocyst doses, appear less critical. Adopting a standardized assay for oocyst infectivity will provide both a basis for comparing data from various oocyst disinfection studies and a suitable platform for evaluating new or existing in vitro viability surrogates such as excystation, vital dyes or cell culture.
Animals↗