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Biomedical subjects

C M Byrne

Publications and source records attributed to C M Byrne.

12 recordsLinked to original sources
PubMed2003

Characterization of Escherichia coli O157:H7 from downer and healthy dairy cattle in the upper Midwest region of the United States.

While cattle in general have been identified as a reservoir of Escherichia coli O157:H7, there are limited data regarding the prevalence and clonality of this pathogen in downer dairy cattle and the potential impact to human health that may occur following consumption of meat derived from downer dairy cattle. In the present study, conducted at two slaughter facilities in Wisconsin between May and October of 2001, we established a higher prevalence of E. coli O157:H7 in fecal and/or tissue samples obtained aseptically from intact colons of downer dairy cattle (10 of 203, 4.9%) than in those from healthy dairy cattle (3 of 201, 1.5%). Analyses of 57 isolates, representing these 13 positive samples (one to five isolates per sample), by pulsed-field gel electrophoresis, revealed 13 distinct XbaI restriction endonuclease digestion profiles (REDP). Typically, isolates from different animals displayed distinct REDP and isolates from the same fecal or colon sample displayed indistinguishable REDP. However, in one sample, two different, but highly related, REDP were displayed by the isolates recovered. Antimicrobial susceptibility testing indicated that 10 of the 57 isolates, recovered from 2 (1 downer and 1 healthy animal) of the 13 positive samples, were resistant to at least 1 of 18 antimicrobials tested. However, there was no appreciable difference in the frequency of resistance of isolates recovered from downer and healthy dairy cattle, and not all isolates with the same REDP displayed the same antimicrobial susceptibility profile. Lastly, it was not possible to distinguish between isolates recovered from downer and healthy cattle based on their XbaI REDP or antimicrobial susceptibility. These results indicate that downer cattle had a 3.3-fold-higher prevalence of E. coli O157:H7 than healthy cattle within the time frame and geographic scope of this study.

Animals↗
PubMed2002

The effect of commercial production and product formulation stresses on the heat resistance of Escherichia coli O157:H7 (NCTC 12900) in beef burgers.

The effects of commercial beef burger production and product formulation on the heat resistance of Escherichia coli O157:H7 (NCTC 12900) in beef burgers were investigated. Fresh beef trimmings were inoculated with E. coli O157:H7 to approximately log10 7.0 cfu g(-1) and subjected to standard beef burger production processes, including freezing, frozen storage and tempering. The tempered trimmings were processed in line with commercial practice to produce burgers of two formulations, a 'Quality' burger containing 100% beef and an 'Economy' burger containing 70% beef and 30% other ingredients (salt, seasoning, soya, onion and water). The burgers were then frozen and stored. Control 'unprocessed' burgers were produced to each of the above formulations using fresh beef trimmings. All burger types were heat-treated at 55, 60 or 65 degrees C. Samples were examined by plating on Tryptone Soya Agar (TSA), incubated at 37 degrees C for 2 h, before overlaying with SMAC (TSA/SMAC) and incubation at 37 degrees C. The resultant counts were used to derive D-values for E. coli O1 57:H7. At each treatment temperature, the D-values from each burger formulation using frozen tempered trimmings were significantly lower (P < 0.001) than the D-values from that formulation using fresh trimmings. At each treatment temperature, the D-values from Economy burgers using processed trimmings were significantly higher (P < 0.001) than the D-values from Quality burgers using processed trimmings. A similar trend of significantly higher (P<0.001) D-values for Economy burgers was observed using fresh trimmings. This study found that commercial processing and product formulation have profound effects on the heat resistance of E. coli O157:H7 in beef burgers.

Animals↗
PubMed2002

Fate of Escherichia coli O157:H7 during silage fermentation.

The survival characteristics of Escherichia coli O157:H7 in silage derived from contaminated grass were investigated. The survival of other enteric bacteria was also investigated to determine if E. coli O157:H7 demonstrates enhanced acid tolerance in comparison. Samples of chopped grass were treated as follows: (i) no additive (control); (ii) inoculation with E. coli O157:H7 to a final concentration of log10 4.0 CFU g(-1); (iii) addition of an 85% solution of formic acid at 3.0 ml kg(-1) grass; and (iv) addition of both E. coli O157:H7 and formic acid, at the above concentrations. Treated 6-kg grass samples were packed into laboratory silos, sealed, and stored at 15 degrees C for up to 180 days. Individual replicate silos were removed from storage periodically and subjected to microbiological and chemical analyses. Chemical analyses of the silage samples indicated that lactic acid-dominant fermentations, with a rapid drop in pH, occurred. Numbers of enteric bacteria decreased from log10 7.0 to 8.0 CFU g(-1) to undetectable levels within 19 days' storage. E. coli O157:H7 did not survive the silage fermentation process, with numbers declining from approximately log10 4.0 CFU g(-1) to undetectable levels within 19 days of ensiling. The pattern of decline in numbers of E. coli O157:H7 was the same as that for the enteric bacteria, indicating that under the conditions tested, the acid tolerance of E. coli O157:H7 was not significantly different from the acid tolerance of other enteric bacteria. This study found that E. coli O157:H7 did not survive a good silage fermentation process, indicating that properly ensiled grass that is correctly stored is unlikely to be a vector for the transmission of the pathogen among cattle.

Escherichia coli O157↗
PubMed2000

The effect of culture growth phase on induction of the heat shock response in Yersinia enterocolitica and Listeria monocytogenes.

The effect of culture growth phase on induction of the heat shock response in Yersinia enterocolitica and Listeria monocytogenes, was examined. Exponential or stationary preconditioned cultures were heat shocked and survivor numbers estimated using selective and overlay/resuscitation recovery techniques. The results indicate that prior heat shock induced increased heat resistance in both micro-organisms to higher heat treatments. Heat-shocked cells of each micro-organism were able to survive much longer than non-heat-shocked cells when heated at 55 degrees C. The size of the change in heat resistance between heat-shocked and non-heat-shocked cells was greatest for exponential cultures (X:X). Results indicate that the overall relative thermal resistance of each pathogen was dependent on cell growth phase. Stationary cultures (S:S) were significantly (P < 0.01) more thermotolerant than exponential cultures (X:X) under identical processing conditions. Under most conditions, the use of an overlay/resuscitation recovery medium resulted in higher D-values (P < 0.05) compared with a selective recovery medium.

Colony Count, Microbial↗
PubMed2000

The effects of preslaughter washing on the reduction of Escherichia coli O157:H7 transfer from cattle hides to carcasses during slaughter.

Fresh bovine faeces were inoculated with a non-toxigenic, antibiotic resistant strain of Escherichia coli O157:H7, spread on the rump areas of 30 heifers and allowed to dry for 24 h. Ten of the cattle then entered the normal slaughter process without further treatment. The remaining cattle were washed with a powerhose for 1 min (10 animals) and 3 min (10 animals) before entering the normal slaughter process. Both washing treatments removed all visible faecal materials on the live animals although a significant reduction (P < 0.05) in E. coli O157:H7 levels on the hides was only observed on those animals which were powerhosed for 3 min. After slaughter, E. coli O157:H7 was detected on carcasses and on the knives and hands of operatives. Preslaughter washing for 3 min did not statistically reduce the numbers of E. coli O157:H7 transferred from the hide to the carcass during slaughter. However, the organism was not detected on three of the four areas of the carcass sampled, indicating that washing may be a suitable method of decontamination animal hides before slaughter and as such deserves further investigation.

Abattoirs↗
PubMed1999

The survival characteristics of a non-toxigenic strain of Escherichia coli O157:H7.

The survival characteristics of a non-toxigenic, antibiotic-resistant strain of Escherichia coli O157:H7 in bovine faeces were investigated. Faecal samples were inoculated with 10(8-9) cfu g-1 of the organism and (i) stored in closed plastic containers at 10 degrees C, (ii) stored in closed plastic containers placed outside or (iii) decanted onto the surface of grazing land. Recovery and enumeration on Sorbitol MacConkey Agar (SMAC) and Tryptic Soya Agar (TSA) revealed that the E. coli O157:H7 numbers in both enclosed samples (i and ii) had decreased by 4.5-5.5 log10 cfu g-1 within 99 d. Numbers in samples decanted onto grassland (iii) decreased by 4.0-5.0 log10 cfu g-1 within 50 d but the organism was still detectable in the surrounding soil for up to 99 d. Persistence of E. coli O157:H7 in bovine faeces and contaminated pastures may therefore be an important factor in the initial infection and re-infection of cattle.

Animals↗
PubMed1994

The importance of relationships in fostering hope.

1. A person with mental illness, such as schizophrenia, can be mobilized to maintain hope. 2. A relationship seems to be the catalyst that allows hope to develop exponentially. 3. A belief in the client's abilities can be a powerful motivator for change.

Adult↗
PubMed1991

Trends in kidney procurement and transplantation in New York State.

The growth in the number of Medicare patients with end stage renal disease (ESRD) in New York State receiving cadaver kidney transplants in the 1980s substantially lagged behind growth in the nation. Compared to the United States, New Yorkers on dialysis had less access to transplants. The greatest decline in transplant rates was experienced by New York's black population. During the early and mid-1980s, considerable transplant rate growth in New York City was maintained, despite very slow growth in local kidney procurement, by importing kidneys from other states, by residents seeking transplants elsewhere, and by a greater proportion of transplants going to Medicare ESRD patients. Since 1986, the number of kidneys procured in New York City increased while the number procured nationally fell. However, kidney imports to New York City dropped dramatically and thus the number of cadaver transplants declined despite the growth in local procurement. Upstate, procurement and transplants started at a higher level, but grew even more slowly.

Cross-Sectional Studies↗
PubMed1991

Skin exposure and thyroid dose distribution using niobium filtration.

A thermoluminescent dosimetry system was utilized to investigate how much the radiation dose is reduced through the addition of a niobium-based accessory filter to an X-ray unit's conventional aluminum filter. A two-bitewing series was exposed in a tissue-equivalent human phantom. The skin exposures from an X-ray beam with the added niobium filter and a beam with the aluminum filter alone were measured and compared. Thyroid dose distribution was also measured and similarly compared. Utilization of the niobium filter resulted in a significant reduction in skin exposure (p less than 0.001) of 14.8 per cent. Thyroid dose was not lessened by using the niobium filter, however. In fact, in one region of the thyroid it increased significantly.

Filtration↗
PubMed1984

Needs assessment and hospice planning in a rural setting.

A needs assessment is a research and planning activity designed to determine a community's service needs and utilization patterns. One of the most practical ways to plan services is to gather information accurately about a defined population and use that information to revise existing programs or develop new ones. Unfortunately, needs assessment findings often go unused. This article describes how a needs assessment was designed to assess the need for hospice services in a rural Pennsylvania county and how the results of this assessment were useful in determining priorities for program planning and service development. The implications of a model needs assessment such as the one proposed are discussed.

Health Services Needs and Demand↗