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Biomedical subjects

N F Lightfoot

Publications and source records attributed to N F Lightfoot.

At least 55 records · Page 3Linked to original sources
PubMed1991

Jackdaws and magpies as vectors of milkborne human Campylobacter infection.

In 1990 we reported that milk bottles pecked by jackdaws and magpies were a probable source of human campylobacter infection. During April to June 1990 an extended study of campylobacter infections was carried out in the Gateshead area. Prior to the study a health education programme was undertaken in an attempt to reduce human infection. Fifty-nine cases of human infection were recorded and 52 were interviewed. Thirty were entered into a case control study which demonstrated a very strong association between consumption of pecked milk and human campylobacter infection (chi 2 = 12.6, P less than 0.0004). It was estimated that between 500 and 1000 jackdaws (Corvus monedula) were present in the area where milk bottles were pecked and 63 isolates of campylobacter were made from the bill and cloaca. Target bottles were put out in the early mornings and campylobacters were isolated from 12 of 123 pecked bottles. Typing of the campylobacters revealed a wide distribution of strains amongst birds, pecked milk and human infections. The health education programme had only limited success.

Adolescent↗
PubMed1991

Epidemiological typing of coagulase-negative staphylococci by pyrolysis mass spectrometry.

Pyrolysis mass spectrometry (PMS) was evaluated for the epidemiological typing of coagulase-negative staphylococci (CNS) in situations in which it was necessary to distinguish between repeated isolation of the same strain from a single patient (genuine infection) and coincidental isolation of unrelated strains (contamination). Thirteen CNS isolates were examined, consisting of five pairs, each pair isolated from a single patient, and three unrelated strains. PMS analysis gave results equivalent to a conventional typing system comprising antibiogram, biotype and plasmid profile analysis. Both methods facilitate differentiation between genuine infection with CNS and the isolation of contaminants. The speed, reproducibility, versatility and relatively low cost of PMS suggest that it may be a valuable new technique for the epidemiological typing of CNS in routine clinical settings.

Coagulase↗
PubMed1990

An epidemiological study of an outbreak of Q fever in a secondary school.

Five cases of clinical Q fever were identified amongst students and staff of a Somerset secondary school between 23 October 1987 and 21 December 1987. Five goats which were kept at the school were found to have antibodies to Coxiella burnetii phase II. A cross-sectional study was conducted at the school in July 1988. A single CF test was used to identify evidence of prior infection, and a self-administered questionnaire was used to collect data on exposure variables and illness during 1987. Four hundred and ninety-nine eligible subjects took part in the study, and serological information was obtained from 461 of these. Eighty-seven subjects (18.9%) had CF titres of 20 or greater. It was estimated that only 1 in every 30 individuals with evidence of past C. burnetii infection had been recognized as a clinical case of Q fever. Antibody positive subjects were more likely to have been off school sick and to report having suffered chest pain than negative subjects. Contact with school animals, specifically cleaning the school poultry, collecting their eggs and visiting a school goat on the day of kidding, was associated with the presence of antibodies to C. burnetii. However, a large proportion of the antibody positives (24.2%) had no known contact with the school animals. Spread of organisms, either wind-borne or in straw or manure, may have been responsible for the high prevalence of unexplained infection.

Adolescent↗
PubMed1990

Management of institutional outbreaks of Salmonella gastroenteritis.

The number of reports of outbreaks of salmonella gastroenteritis in hospitals has decreased since 1984 but the number of outbreaks in institutions such as old peoples' homes have increased during 1988. Foods, particularly chickens, remain a source of salmonellae and particular attention has to be paid to training and practices in food preparation areas. Staff who are convalescent are very unlikely to be sources of salmonella and do not need to be excluded unless they handle food that receives no further cooking. Outbreaks that do occur can usually be controlled by patient isolation and good control-of-infection measures and an effective Major Outbreak Control Plan is necessary. In some large old hospitals cross infection outbreaks may continue despite good control-of-infection measures. Antibiotics have been contraindicated in the treatment of salmonella gastroenteritis, but the new 4-quinolone antibiotics have demonstrated potential. Ciprofloxacin was used successfully in two outbreaks of salmonella gastroenteritis at a dose of 500 mg bd orally for seven days. Relapses did not occur and resistance did not develop. Ciprofloxacin should be considered as a therapeutic adjunct to control of infection measures in cross infection outbreaks in these situations.

Anti-Bacterial Agents↗
PubMed1990

Pyrolysis-mass spectrometry (Py-MS) for the rapid epidemiological typing of clinically significant bacterial pathogens.

Fresh clinical isolates of Salmonella spp. and Streptococcus pyogenes were analysed by pyrolysis-mass spectrometry (Py-MS). The results formed the basis of mathematically derived characterizations of individual strains and these were compared with the results of phage typing for the salmonellas and M protein typing for the streptococci. Py-MS was shown to be a rapid and reproducible method for inter-strain comparisons, giving evidence of identity and non-identity between strains that agreed well with the results of conventional tests. Py-MS has potential value as a rapid, relatively inexpensive and highly discriminatory method of epidemiological analysis in bacterial disease.

Bacterial Typing Techniques↗
PubMed1990

Validation of a method for the rapid diagnosis of urinary tract infection suitable for use in general practice.

A combination of reagent strip testing and examining urine appearance can be used to screen out noninfected cases before urine specimens are sent to the laboratory. A validation of this method was carried out in a microbiology laboratory using 970 specimens received over a three-week period. When the tests for nitrite, blood and protein on N-Multistix reagent strips (Ames) were all negative in a clear urine then the predictive value for the absence of bacteriuria was 98.5%. Positive strip tests in a turbid urine detected 80.1% of infections. On the basis of these findings it is recommended that general practitioners test the urine samples of all patients with suspected urinary tract infections by this method and only send to the laboratory those specimens with positive findings. Using this method the routine laboratory workload involved in testing urine specimens would be reduced by 40%, instant results would be available in the general practitioner's surgery and the patient would receive immediate and appropriate treatment.

Bacteriuria↗
PubMed1989

Outbreaks of astrovirus type 1 and rotavirus gastroenteritis in a geriatric in-patient population.

Two outbreaks of viral gastroenteritis occurred in seven psychogeriatric wards of a 469-bed psychiatric hospital. The outbreaks occurred over an eight-week period; the first affected 30 people and rotavirus was detected in 12 of 14 persons from whom faecal specimens were available. The second affected 32 people (15 of whom were affected in the previous outbreak) and astrovirus was detected in 5 of the 24 people from whom specimens were available. Specific IgM to astrovirus was demonstrated in 3 patients. The rotavirus outbreak was characterised by a longer duration of illness (mean 4 days), and more severe symptoms; two elderly female patients had severe symptoms over a 14-15 day period but recovered. In the astrovirus outbreak the duration of illness was shorter and symptoms were milder although the attack rate was higher than that observed for rotavirus.

Adult↗
PubMed1989

A community outbreak of group A beta haemolytic streptococci with transferable resistance to erythromycin.

Erythromycin resistance amongst group A streptococci (GAS) in Great Britain is a relatively rare occurrence and outbreaks have been sporadically reported. Over an 8-month period in 1986 ten associated cases occurred in the town of Bridgewater in Somerset. Isolates were group A, type M4 and resistant to erythromycin (MIC 8 mg/l) but sensitive to lincomycin and clindamycin. Erythromycin resistance was transferable from all isolates to a group A recipient strain. No plasmid DNA could be detected in the original isolates or transconjugants.

Adult↗
PubMed1988

Carriage of Neisseria meningitidis: investigations in a military establishment.

A prevalence study of personnel on a Royal Naval Air Station revealed that 23.0% of 2479 personnel were carrying a meningococcus. Selected groups of personnel were subsequently swabbed monthly for a year. We have shown that it is only by repeated swabbing and the use of optimal methods including enrichment media that one can have a hope of identifying the 'true' carriage rate. A presumed virulent strain of Neisseria meningitidis B15 P1.16 was repeatedly isolated from three personnel who remained well, as did their colleagues both at their work place and socially. The study served to emphasize our lack of knowledge of the virulence factors associated with N. meningitidis.

Adult↗
PubMed1988

Solid-phase immune electron microscopy with human immunoglobulin M for serotyping of Norwalk-like viruses.

A solid-phase immune electron microscopy method that uses protein A, goat anti-human immunoglobulin M (IgM), and human serum is described. Evaluation of the method with different immunoglobulin fractions showed that human IgM constituted the major virus capture antibody. The method appeared to distinguish between two Norwalk-like virus serotypes and demonstrated specific IgM responses to these serotypes in infected individuals. Further work is being carried out to define the relationship of these two serotypes to the previously described Norwalk agent (A. Z. Kapikian, R. G. Wyatt, R. Dolin, T. S. Thornhill, A. R. Kalica, and R. M. Chanock, J. Virol. 10:1075-1081, 1972), and four subsequent hospital outbreaks are being studied.

Humans↗
PubMed1982

Intragastric acidity, bacteria, nitrite, and N-nitroso compounds before, during, and after cimetidine treatment.

Eight healthy subjects were studied half-hourly or hourly for 24 h periods before, during, and after cimetidine treatment. No significant differences in intragastric bacterial counts or bacterial species or in intragastric nitrite or N-nitroso-compound concentrations were found as a result of cimetidine treatment. Bacterial counts and nitrite concentrations tended to increase with pH, but N-nitroso-compound concentrations did not. This study provides no evidence that cimetidine treatment may increase the risk of gastric carcinoma by raising N-nitroso-compound concentrations.

Bacteria↗
PubMed1982

A large outbreak of streptococcal pyoderma in a military training establishment.

An outbreak of streptococcal pyoderma in a military institution into which fresh susceptible recruits were regularly introduced involved more than 1300 persons over an eighteen-month period. Two M types were responsible for the great majority of the cases and an attack by one conferred immunity to that strain but not to the other. Lesions varied from trivial to disabling. Epidemiological studies indicated that contact -- direct or indirect -- through such things as gymnasium equipment and room dust was the means of transmission. The outbreak was eventually controlled by vigorous case finding, thorough treatment of cases and the strict application of hygienic principles to prevent spread. There were no late complications and throat streptococci were not involved. It is possible to control such an outbreak without isolation or the making of any significant concessions in the training programme even when large numbers of persons are living and working at close quarters.

Follow-Up Studies↗
PubMed1978

Diagnosis of Bacteroides fragilis infection with counter-immunoelectrophoresis.

In a study of 188 patients and 109 controls, the detection of antibody by counterimmunoelectrophoresis was used as a diagnostic aid in human infections with Bacteroides fragilis. It was found that positive results indicated current infection and negative results were not conclusive. The method used was simple, rapid, and easily performed in a routine laboratory, but further work is needed to enhance antigen potency.

Antibodies, Bacterial↗