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PubMed2000

Modern laboratory diagnosis of mycobacterial infections.

This review summarises recent advances made in microscopic techniques (fluorescence and peptide nucleic acids) and culture techniques (solid, liquid, radiometric, and non-radiometric systems) and in the development of rapid methods for the identification of mycobacterial cultures (high performance liquid chromatography, thin layer chromatography, RNA sequencing, and polymerase chain reaction restriction enzyme assays). The role of molecular amplification systems in identifying Mycobacterium tuberculosis is described. Most methods record high specificity and sensitivity for smear positive sputum but have variable sensitivity for sputum smear negative and extrapulmonary specimens. Specimen quality will affect the performance of these assays and organisational delays, such as the batching of specimens, can reduce the time saved. In house assays can be as effective as commercial systems as long as appropriate controls are used.

Bacterial Typing Techniques↗
PubMed2002

Laboratory confirmation of meningococcal disease in Scotland, 1993-9.

AIMS: To describe the laboratory confirmation of meningococcal disease, using culture and non-culture based techniques, between 1993 and 1999 as part of a national service in Scotland. METHODS: Samples from patients with suspected meningococcal disease in Scotland were analysed by culture and non-culture based techniques to gain a laboratory confirmation of disease. Data were analysed to establish the number of disease cases, the serogroups of the organisms involved, and the importance of the techniques used. RESULTS: Between 1993 and 1999, there was a total of 1749 notified cases of meningococcal disease in Scotland. Culture based methods provided a laboratory confirmation of 788 cases whereas non-culture techniques confirmed 461 cases. CONCLUSIONS: Non-culture techniques were a useful addition to culture based techniques in Scotland and improved the dataset required for public health management, disease surveillance, and vaccine policy.

Agglutination Tests↗
PubMed2002

Detection of campylobacter species: a comparison of culture and polymerase chain reaction based methods.

AIMS: To investigate the optimal method for the detection of campylobacters from stool samples by comparing selective culture with membrane filtration and the polymerase chain reaction (PCR). METHODS: Three hundred and forty three stool samples were investigated by each of the three methods mentioned above. Selective culture was performed with charcoal cefoperazone desoxycholate agar plates. Membrane filtration was performed using cellulose triacetate membranes with 0.45 micro m pores placed on blood agar plates. Enteropathogenic campylobacters were detected using a PCR identification algorithm, consisting of screening PCRs and species identification using a PCR enzyme linked immunosorbent assay (PCR-ELISA), both based on the 16S rRNA gene. RESULTS: Of the 343 samples tested, 23 were positive by one or more method. Of these, 17 were positive by selective culture, 12 by membrane filtration, and 20 by the PCR identification algorithm. A total of 18 of 23 positives were identified as C jejuni and/or C coli by the PCR identification algorithm, compared with 14 identified to the genus level by selective culture, and 10 by membrane filtration. Among the remaining five positive samples, one C hyointestinalis was detected only by the PCR identification algorithm; one C upsaliensis was detected only by the PCR identification algorithm; one Campylobacter sp was detected by membrane filtration and selective culture and later identified as C concisus; one Campylobacter sp was detected by membrane filtration alone and later identified as Arcobacter sp; and one Campylobacter sp detected only by selective culture was lost to study and therefore not speciated. There was no significant difference between detection by selective culture and the other two methods. However, detection by PCR was significantly better than by membrane filtration (0.05 > p > 0.02). CONCLUSION: The PCR identification algorithm can detect and identify Campylobacter spp to the species level and the result is obtained on the same day. However, PCR is expensive, labour intensive, and does not provide an isolate for further identification or typing. Selective culture is as good as the PCR identification algorithm for the detection of the two most common species, C jejuni and C coli, and it is cheap and practical. However, it does miss the less common species, results take 48 hours, and identification is only to the genus level. Membrane filtration showed a low sensitivity compared with the other methods and is not appropriate for the diagnostic laboratory, although it was the only method to detect the Arcobacter sp. The optimum method for the detection of campylobacters from stool samples in the diagnostic laboratory remains selective culture.

Agar↗
PubMed1989

Control, prevention and eradication of Salmonella enteritidis infection in broiler and broiler breeder flocks.

Salmonella enteritidis was identified by serological and bacteriological techniques in two clinically normal breeder flocks in an integrated broiler organisation in Northern Ireland. The organism was transmitted vertically to clinically affected progeny flocks. The infected breeder flocks were slaughtered and the infection throughout the organisation controlled and subsequently eradicated. A working group, consisting of the senior management of the broiler organisation and veterinary staff from the Veterinary Research Laboratories at Stormont, was formed to establish procedures to minimise the risk of the reintroduction of salmonella infection, by preventing vertical transmission from grandparent flocks, or lateral transmission from personnel, other animal species and fomites, or transmission through the feed. All feed was heated to a minimum of 70 degrees C for 12 minutes immediately before it was pelleted and subsequently transported to the flocks through a dedicated system of conveyor belts, bins and lorries. A comprehensive system for monitoring the efficacy of the preventive procedures was established and is now used throughout the poultry industry of Northern Ireland.

Animals↗
PubMed2003

Phenotypic characteristics and population genetics of Enterococcus faecalis cultured from patients in Tehran during 2000-2001.

Conventional bacteriology techniques were used to identify enterococci isolates cultured from patients at different hospitals in Tehran during 2000-2001. The identification was confirmed using species-specific PCR targeting the D-alanyl-D-alanine ligase gene. A total of 59 isolates of Enterococcus faecalis were identified. The rates of resistance to different antibiotics were in the following order: penicillin 84%, ciprofloxacin 42%, high-level gentamicin 30%, nitrofurantoin 14%, imipenem 4%, and chloramphenicol 2%. Resistance to ampicillin was found to be rare among the Iranian isolates of E. faecalis. Multi-locus enzyme electrophoresis was then used to analyze the strains. Forty-five electrophoretic types were obtained when 10 enzyme loci were screened. Although the collection of bacterial isolates was limited in time and location, considerable heterogeneity was found. Analysis of strains for linkage disequilibrium demonstrated that the studied population is not clonal, since the index of association was not significantly different from zero (Ia = 0.0296). Enterococcus faecalis isolates recovered from patients in Tehran were genetically diverse and seemed to possess a high potential for genetic recombinations, though none were resistant to vancomycin.

Anti-Bacterial Agents↗
PubMed2004

Potential application of low-stringency single specific primer-PCR in the identification of Leptospira in the serum of patients with suspected leptospirosis.

In this study we tested the potential use of low-stringency single specific primer-PCR (LSSP-PCR) for genetically typing Leptospira directly from biological samples. Serum samples obtained from 29 patients with clinically suspected leptospirosis were amplified by specific PCR, using the previously selected G1 and G2 primers. The PCR products of approximately 300 bp were subsequently used as a template for LSSP-PCR analysis. We were able to produce genetic signatures from the leptospires present in the human samples, which permitted us to make a preliminary identification of the infective serovar by comparing the LSSP-PCR profiles obtained directly from serum samples with those from reference leptospires. Thus, LSSP-PCR has the potential to become a useful diagnostic tool for identifying leptospires in biological samples without the need for bacteria isolation and culture.

Bacterial Typing Techniques↗
PubMed1978

Biochemical pharmacology of the intestinal flora.

Animal and bacteriological techniques have been developed for clarifying the role of the flora in the metabolism of drugs and other exogenous compounds. In general the flora tends to catalyze reductive and hydrolytic reactions, some of which reverse the detoxification reactions normally occurring in the liver. These reactions and others have been implicated in the pharamacological or toxicological action of exogenous compounds. Only in a few instances, however, have practical consequences of these reactions been documented. The major challenge at present is to develop methods capable of further defining the implications of reactions due to the flora.

Animals↗
PubMedDate not supplied

Quantitative bacteriology in adenoid tissue.

Over the past several years the indications for adenoidectomy have become increasingly controversial. Attempts to justify the operation in recurrent otitis media by correlating cultures of the nasopharynx with cultures of middle ear fluid have been inconclusive. Using quantitative bacteriologic techniques, we have studied the levels of aerobic and anaerobic bacteria per gram of tissue in adenoids removed from 48 patients. In seven patients, adenoidectomy was performed for nasal obstruction alone, in 17 patients for chronic serous otitis media, and in 24 patients for recurrent suppurative and serous otitis media. Using the criterion that greater than 10(5) organisms/gm of tissue constitutes infection, we found that 83% (20) of patients in the third group had infected adenoids, as opposed to only 15% (4) in the first and second group combined. Adenoid size measured radiographically did not correlate with the presence of infection. Adenoid size measured radiographically did not correlate with the presence of infection. When recurrent suppurative and serous otitis media are unresponsive to medical therapy including antibiotics and decongestants, adenoidectomy should be considered in addition to myringotomy and ventilation tubes.

Adenoidectomy↗
PubMed1985

Pathology of cloacal bursae of gnotobiotic turkeys orally inoculated with Escherichia coli.

Cloacal bursae from three-week-old gnotobiotic turkeys were examined by light and electron microscopy and bacteriologic techniques at 1, 2, 5, 8, 12, and 16 days after oral inoculation of highly virulent (group 1) and weakly virulent (group 2) Escherichia coli. In both groups a significant decrease in follicular volume and increase in interstitial volume were associated with infection. Follicular cortical, follicular medullary and total follicular transectional areas increased with time in inoculated and control turkeys. In group 1, granulocytic inflammation developed in bursae on day 1 and diminished by day 8 after inoculation. Microabscesses were present on days 5 and 8 after inoculation in less than 1% of follicles. Bacteria were seen in few follicular medullae on days 5 and 8 after inoculation; bacteremia was detected on days 1, 2, and 5 after inoculation. In group 2, pyogranulomatous bursitis was first seen at five days after inoculation and became progressively more severe with time. Follicular alterations in group 2 included abscessation, lymphocyte necrosis, reticuloepithelial hyperplasia and perifollicular fibroplasia. Ultrastructurally, follicular pads had degenerate and necrotic epithelial cells, intercellular edema, and cystic spaces that contained acidic mucosubstances and laminar deposits of calcium salts. Bacteria were seen within necrotic centers of follicular abscesses, in phagosomes of macrophages and multinucleate giant cells and within extracellular spaces of follicular pads and follicular medullae from day 5 to day 16 after inoculation; no bacteremia was detected. We conclude that E. coli passes through the bursal follicle-associated epithelium and replicates within follicular medullae, that extensive follicular necrosis is associated with persistence of E. coli in follicular medullae, and that E. coli of low virulence may cause severe pyogranulomatous bursitis in young turkeys without causing the respiratory or systemic diseases which are commonly associated with organisms of high virulence.

Animals↗
PubMed2003

Etiology and risk factors of 339 cases of infective endocarditis: report from a 10-year national prospective survey in the Slovak Republic.

The authors studied the etiology, outcome and risk factors of 339 cases of infective endocarditis (IE) in Slovakia over the last 10 years. Aortic valve was infected in 59.9%, mitral in 38.1% and tricuspidal/pulmonary in 5.0% of cases. The majority of IE were caused by staphylococci (29.2%), 15.0% were due to viridans streptococci, 7.4% due to Enterococcus faecalis, 3.9% due to the HACEK group (Haemophilus spp., Actinobacillus spp., Corynebacterium spp., Eikenella spp., Kingella spp.) and 39.2% were culture negative. The following risk factors were the most frequently identified: rheumatic fever in 24.2%, dental surgery in 13.3%, previous cardiosurgery in 7.1% and neoplasia in 7.1%. All patients were treated with antimicrobials and 42.5% of patients also with surgery (valvular prosthesis replacement): 61 (18.0%) died, and 278 (82.0%) survived at day 60 after the diagnosis of endocarditis was made. Univariate analysis did not show significant differences in most of the recorded risk factors between patients who died and those who survived: apart from staphylococcal etiology (44.3% vs. 26.6%, P < 0.01), persistent bacteremia (with three or more positive blood cultures 24.6% vs. 9.7% P < 0.002) which were significantly associated with higher attributable mortality, as was absence of surgery (55.7% vs. 6.1% P < 0.001), whereas antibiotic therapy in combination with surgery significantly predicted better outcome (P < 0.001). We compared risk factors, etiology, therapeutic strategies and outcome of IE in two periods: from 1991-1997 (180 cases) and from 1998-2001 (159 cases). Rheumatic fever was less commonly observed in second period (1998-2001) P < 0.01 since its prevalence in Slovakia is rapidly decreasing. Dental surgery was less frequent as well (20.5% vs. 5.0% P < 0.001). There was a significant shift in etiology within the second study period: negative-culture endocarditis (despite better bacteriological techniques) (P < 0.001) was more frequently observed in the 1st period and represented 53.3% of all cases in 1998-2001 in comparison to 26.7% in 1991-1997. Enterococci (P < 0.0002) were also more frequent in the 2nd period. Persistent bacteremia (3 or more positive blood cultures 20.5% vs. 3.1%, P < 0.001 was less commonly observed within the 2nd period (1998-2001) in comparison to 1991-1997. More patients in the second period (1998-2001) had complications of IE (P < 0.001) than in the 1st period. However mortality was lower (22.2% vs. 13.2%, P < 0.044) because of more surgical intervention in the 2nd period (52.8% vs. 33.3%, P < 0.001).

Adult↗
PubMed1994

Effectiveness of Bifidobacterium bifidum in mediating the clinical course of murine rotavirus diarrhea.

Human Bifidobacterium sp strain bifidum (B. bifidum) was administered to BALB/c lactating mice (n = 58) and their litters (n = 327 pups) to evaluate the ingested strain's adherent properties and ability to inhibit murine rotavirus (MRV) infection. ELISA and anaerobic bacteriologic techniques were used to measure MRV shedding and colonization of Bifidobacterium in the small intestine. At 13-16 d gestation, pregnant dams (and their expected litters) were randomly assigned to one of four experimental groups: 1) normal controls; 2) B. bifidum-treated only; 3) MRV-infected only; and 4) B. bifidum-treated + MRV-infected dams and litters. During the acute phase of diarrhea, 80% of small-intestine cultures in B. bifidum-treated litters were positive for the ingested B. bifidum strain compared with 24% of fecal cultures. Examination of tissue cross sections under electron microscopy revealed the ingested B. bifidum strain survived passage through the upper gastrointestinal tract and adhered to the small-intestine epithelium. After the administration of the high dose of virus, diarrhea developed in all pups, but onset was significantly delayed in B. bifidum-treated + MRV-infected litters compared with litters infected with MRV only (p < 0.02). B. bifidum-treated+MRV-infected pups demonstrated a significant reduction in MRV shedding compared with litters challenged with MRV only at d 2 to 10 after inoculation (p < 0.009). More direct studies are needed to assess mechanisms by which this anaerobe can alter the course of MRV infection at the level of gut epithelium.

Administration, Oral↗
PubMed1976

A quantitative measurement of bacteremia and its relationship to plaque control.

Despite the improvement in the patients' oral hygiene, there was no significant decrease in the frequency of bacteremia. There was no significant difference in bacteremia between brushing, flossing, or deplaquing either before or after initial periodontal preparation and plaque control in 21 healthy subjects. Utilizing more sophisticated bacteriologic techniques for the cultivation of obligate anaerobes, a relatively high frequency of anaerobic bacteremia was found.

Bacteria↗