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PubMed2003

The clinical relevance of microbiologic testing. Part 2: a comparative analysis of microbiologic samples secured simultaneously from the same sites and cultured in the same laboratory.

A field study using four different private periodontal practices and two independent laboratories was conducted to compare two microbiologic cultures sampled simultaneously from the same sites in 20 individual patients. Both paired samples were submitted separately to one of the two independent laboratories for bacterial identification and antibiotic sensitivity testing. The results from the two samples were quite variable. In only two instances did both specimens reveal the presence of identical bacterial species, but these specimens differed in both threshold levels and antibiotic sensitivity. When only bacteria above threshold levels were compared, total agreement was found in 11 of 20 cases. When examining antibiotic sensitivity, using 100% kill as the ideal, agreement between the two specimens was inconsistent The use or nonuse of tetracycline was in agreement 85% of the time, amoxicillin 75% of the time, metronidazole 70% of the time, and amoxicillin-metronidazole in combination 85% of the time. The two specimens agreed on the empirical use of amoxicillin 45% of the time, tetracycline 60% of the time, and metronidazole 60% of the time. The empirical use of amoxicillin-metronidazole in combination yielded 80% agreement when the results of both specimens were combined. The empirical use of amoxicillin-metronidazole combination therapy may be more clinically sound and cost effective than culturing and antibiotic selection based on the culture from any single microbiologic testing laboratory. This supports the data from a previous study that examined specimens secured simultaneously from the same site and submitted to two different testing laboratories. The failure of microbial testing to achieve a higher level of consistency between samples leaves the clinical efficacy of microbial testing in question.

Adult↗
PubMedDate not supplied

[Microbiology of leg ulcers and microbiologic diagnosis of the infection].

Of all the complications which can interfere with healing, infection is among those which have a greater impact not only on the wound but also on the patient's quality of life and on the costs of care. The author addresses the microbiology of leg ulcers, the problem of the qualitative versus quantitative analysis and the continuing debate regarding the indication for sampling wounds, methods and interpretation of the results in the microbiological diagnosis of wound infection.

Bacterial Infections↗
PubMed1990

[Trends in medical microbiology--gene probes in medical microbiology].

At first the principle of nucleic acid hybridisation, some important technics used heretofore, and methods to label nucleic acids are described. The advantages and disadvantages regarding to the application to microbiological diagnostics are discussed. The advantage, before all, is the high specificity of the test which allows to detect the presence and the properties of genes which are not expressed. The methods known up to now can only be applied if the probe is labelled radioactively, since under these conditions the sensitivity is high enough to identify bacteria contained in clinical isolates without prior cultivation. The comparable complex methods are restricted, presently, to special mostly epidemiological problems. To improve these technics regarding increased sensitivity, to the use of non-radioactively labelled probes, to higher speed, and to the automation of the test internationally much work is carried out with great intensity. The solution of these problems will create conditions for a wide application of DNA probes in the general microbiological laboratory.

Bacteria↗
PubMed1978

[Application of a new method for the calculation and description of the resistance of microbiological indicators. I. Testing of several common microbiological sterilization indicators (author's transl)].

The method described by SPICHER and PETERS (1975) for the calculation and description of the resistance of microbiological indicators was tested. As test objects served spore-containing earth according to DIN 58946, Attest indicators (3 M Company, Minnesota) and Oxoid Spore Strips (Oxoid Ltd., London). The tests were performed not only for different batches of indicators but also for preparations of different age. After application of steam (120 degrees C), the indicators were examined for the presence of surviving germs capable of multiplication. When plotting the frequency of indicators with surviving germs (q) against the duration of steam action, S-shaped curves were obtained as expected. By altering the scale of the ordinate (y = lg (-ln(1 - q))), the S-shaped curves could be transformed into straight lines. Thus, the experimentally established paired values could be used for a calculation of regression. This method of calculation proved to be suitable in all cases studied. By indicating the position and the slope of these straight regression lines, the resistance of microbiological indicators can be exactly described (cf. Table 2). This method is applicable not only to indicators containing culture spores but also for native spore-containing earth. The indicators examined differed in their resistance and stability. Seven out of eight batches of Attest indicators (cf Figs. 1 and 2 and Table 1) fulfilled the requirements of DIN 58946, Part 4, for the resistance of bio-indicators for steam sterilization. One of the batches had a slightly higher resistance. The Attest indicators tested were of good stability (see Fig. 1 and Table 1). Where surviving germs were present on the indicators after treatment by steam, their growth was recognizable, in 99% of cases, already after incubation of the cultures for 24 hours. Only two batches of Oxoid Spore Strips were available for testing. One batch was of a higher resistance than required by DIN 58946. The second batch was slightly above the lower limit of the permissible range (see Fig. 3). During storage for 12 months, the resistance of both batches was reduced by 3--4 min. Where the indicators exhibited surviving germs after treatment by steam, growth was recognizable in 87% of the cases after incubation for 24 hours, while for the other indicators, incubation for 48 hours was necessary. The experiments confirmed the good stability of native spore-containing earth (see Fig. 5). Within 4--5 years, the steam resistance of the preparations decreased only by 3--4 min.

Bacteriological Techniques↗
PubMedDate not supplied

[Medical aspects of elaboration of microbiological criteria for evaluating the quality and principles of microbiological standards of dried milk and other mixtures for children in the first year of life].

The author demonstrates the ability of St. aureus, E. coli O III, B. cereus and other opportunistic microorganisms to multiply in model media similar to those in the alimentary tract of children of the first year of life. Describes the principal differences between microbiological criteria of evaluating the quality and safety of infant food mixtures and other products intended for children of the first year of life and these criteria for consumer goods. Emphasizes that food mixtures for infant nutrition should not contain potentially pathogenic and pathogenic microorganisms. At the present stage of manufacturing food for children of the first year of life the microbiological criteria are based on an assay of mesophilic aerobic microorganisms in 1 g (ml) and on the determination of the mass of the ready-made mixture or other product which should not contain E. coli that ferment glucose, coliform bacteria, lactose, E. coli, St. aureus, salmonella, yeast and mold.

Animals↗
PubMed1996

Quality improvement of diagnostic microbiology through a peer-group proficiency assessment program. A 20-year experience in Ontario. The Microbiology Committee.

OBJECTIVE: To evaluate the microbiology laboratory performance in Ontario over a 20-year period of participation in a quality assessment program and to assess the impact of quality improvement strategies. DESIGN: Longitudinal review of isolation, identification, and antimicrobial susceptibility testing of bacteria from lyophilized, simulated patient samples. SETTING: Ontario medical laboratories, licensed by the Ministry of Health, have been subjected to mandatory testing by the Laboratory Proficiency Testing Program of the Ontario Medical Association since 1974. Survey reports, information bulletins, correspondence, on-site consultations, educational assistance tutorials, and teleconference education are used as quality improvement strategies. PARTICIPANTS AND INTERVENTIONS: Laboratories were subjected annually to 20 external quality assessment challenges. Performance was assessed against consensus reference values. Single survey and cumulative profiles were reviewed by a peer-group panel for acceptable or unacceptable performance. Specific interventions are used to improve collective and individual laboratory performance. RESULTS: The number of microbiology laboratories declined from 335 in 1974 to 190 in 1994. Twenty-one percent failed expected performance standards on initial review. One hundred forty-two on-site consultations and 61 educational assistance tutorials have been provided. Twenty-five laboratories were declared nonproficient. Since 1989, 50% of the laboratories have scored at or above 80% for isolation and identification, but 25% have scored at or below 50% on susceptibility testing, and 10% or fewer have scored at or above 80%. Poor susceptibility testing performance is due to inappropriate agent selection, not testing errors. CONCLUSIONS: The emphasis of the Laboratory Proficiency Testing Program is on quality improvement, not punishment. Performance has improved, but poor performers have the same characteristics as in 1974. Identification to species is common owing to the use of commercial systems. Automated susceptibility testing has increased to 45% of participants.

Bacterial Infections↗
PubMed1992

Oral microbiology: current concepts in the microbiology of dental caries and periodontal disease.

The microbial flora of the mouth is highly complex, containing a wide variety of bacterial species. The most common types of oral disease, dental caries and periodontal disease, are both related to dental plaque and seem to occur when the normal balance between the microorganisms and the host is disturbed in some way. Dental caries is usually associated with increased numbers of mutans streptococci and lactobacilli at the sites of disease; estimation of salivary levels of these organisms may be useful for assessing caries risk in patients and for monitoring their response to preventive measures. A large number of 'candidate pathogens' have been identified as potential aetiological agents in different types of periodontal disease, although the 'specific plaque hypothesis' may still be controversial. Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans, together with the poorly understood spirochaetes, have most frequently been reported as significant periodontopathogens and a number of possible virulence factors have been described. Application of modern molecular techniques to the study of the microbiology of oral diseases should allow rapid further progress to be made and will lead, hopefully, to improved methods of diagnosis, risk assessment and treatment.

Animals↗
PubMed1997

Microbiological findings and clinical treatment procedures in endodontic cases selected for microbiological investigation.

The relationship between bacteriological findings and clinical treatment procedures was investigated in root canal treatment cases that were selected for bacteriological investigation by general dental practitioners in Finland. The cultures were sent to the Oral Microbiological Service Laboratory at the Institute of Dentistry in Helsinki. Two groups of teeth were selected based on the type of infection present in the root canal system. The 'enteric bacteria' group consisted of 40 sequential cases where Enterococcus faecalis and/or other facultative enteric bacteria or Pseudomonas sp. were found in the samples in pure culture (35%) or together with other types of bacteria. The group 'non-enteric bacteria' consisted of 40 sequential cases where only non-enteric bacteria were found. The dentists who had sent the bacteriological samples received a questionnaire where they were asked about the treatment protocol and procedures. A total of 70 out of 80 questionnaires were returned. If the root canals had been unsealed at some point during the treatment, enteric bacteria were found more frequently than in canals with an adequate seal between the appointments. Of cases with enteric bacteria 55% had been open during the treatment, while in the group where only non-enteric bacteria were found 30% had been open. Enteric bacteria were also more frequently isolated in cases with a high number of appointments before sampling. In the enteric bacteria group 35% of the samples were taken at the 10th visit or later, while the corresponding percentage in the non-enteric group was 3%. In addition, the number of retreatment cases was significantly higher, 12 out of 34, in the enteric bacteria group than in non-enteric bacteria group, which was five out of 36. Other clinical parameters showed no differences between the two groups. The results emphasize the importance of controlled asepsis throughout the root canal treatment.

Chi-Square Distribution↗
PubMed2003

The Welsh Food Microbiological Forum and the All-Wales Shopping Basket Sampling Program: a model for the surveillance of microbiological quality in ready-to-eat foods.

In the United Kingdom, the monitoring of microbiological food quality and the prevention of foodborne disease are the responsibility of a number of different organizations. In 1993, to develop and extend ongoing local collaborations within selected local food groups in Wales (comprising local authorities and the Public Health Laboratory Service), the Welsh Office invited all local food groups in Wales to create a forum to coordinate the sampling and examination of ready-to-eat foods and the centralized collection of results for the whole of Wales. This paper describes the development, structure, and aims of the forum. It also discusses the outcomes of the first nine years of activities, describes the randomized sampling program for ready-to-eat foods that has been developed; and assesses the benefits that have resulted.

Food Contamination↗
PubMed1991

Antimicrobial susceptibility testing trends and accuracy in the United States. A review of the College of American Pathologists Microbiology Surveys, 1972-1989. Microbiology Resource Committee of the College of American Pathologists.

The ability of the College of American Pathologists Microbiology Surveys subscriber laboratories to perform antimicrobial susceptibility testing accurately has improved slightly since 1984. Currently (1989 surveys), the accuracies for disk diffusion and minimum inhibitory concentration antimicrobial susceptibility testing were 98.2% and 96.1%, respectively. Disk diffusion testing has recently (since 1986) become more popular, along with rapid automated systems, such as the AMS-Vitek System (St Louis, Mo). Rapid tests for beta-lactamase and chloramphenicol acetyltransferase have performed well. Quality control procedures have switched to a cost-effective weekly frequency pattern for nearly 70% of laboratories. Some antimicrobial susceptibility testing problems still exist among anaerobic bacterial methods, procedures for fastidious organisms (Haemophilus, Streptococcus species, Moraxella, pneumococci, gonococci), tests for oxacillin-resistant staphylococci, and the methods for use against nonenteric gram-negative or gram-positive bacilli. Antimicrobial susceptibility testing users subscribing to the College of American Pathologists surveys should strictly follow the National Committee for Clinical Laboratory Standards interpretive and quality control criteria to assure the best performance with the Clinical Laboratory Improvement Act, 1988, compliant College of American Pathologists proficiency sample program.

Bacteria↗
PubMed1998

Potential application of risk assessment techniques to microbiological issues related to international trade in food and food products. International Commission on Microbiological Specifications for Foods (ICMSF) Working Group on Microbial Risk Assessment.

One of the components of the General Agreement on Tariffs and Trade Sanitary and Phytosanitary agreement that will have far-reaching effects on international trade in foods and food products is the requirement for countries to provide risk assessments as part of the process of resolving disputes that involve food safety issues. Risk assessment is a means of evaluating the likelihood and impact of hazards. It provides a framework for systematically considering available data, providing rationales for assumptions, and identifying areas where additional information is needed. While the application of quantitative risk assessment techniques to microbial food safety has been limited, recent studies have increasingly demonstrated its feasibility. Quantitative risk assessment is particularly well suited for use with the hazard analysis critical control point and appears to have potential as an approach for comparing the equivalence of international food safety programs and inspection systems.

Food Microbiology↗