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PubMed1993

How far should a clinical laboratory go in identifying anaerobic isolates, and who should pay?

Identification of anaerobic bacteria in specimens from sites of infection due to mixed organisms can be time-consuming and expensive. Laboratories should limit anaerobic workups by testing only those specimens that have been properly collected and transported to the laboratory. Use of selective and differential media for initial processing can provide rapid and relevant information to the clinician. Anaerobes isolated from normally sterile sites and sites of serious infection should always be completely identified. Group- or genus-level identifications may suffice in other instances. The Bacteroides fragilis group of organisms should always be identified because of their virulence and resistance to many antimicrobial agents. Some of the other organisms that warrant identification include Clostridium septicum (associated with gastrointestinal malignancy); Clostridium ramosum, Clostridium innocuum, and Clostridium clostridioforme (which are resistant to antibiotics); Clostridium perfringens (a cause of potentially serious infection); anaerobic cocci (which may be resistant to metronidazole and clindamycin); and fusobacteria (which may be virulent and resistant to clindamycin and penicillin).

Bacteria, Anaerobic↗
PubMed1996

Moraxella catarrhalis: pathogenic significance in respiratory tract infections treated by community practitioners.

We prospectively studied the pathogenic significance of Moraxella (Branhamella) catarrhalis isolated from 212 patients of community practitioners in Australia. This organism was most commonly isolated during winter and early spring, and 92% of isolates were beta-lactamase producers. On the basis of predetermined clinical and microbiological criteria, 42% of the isolates were definitely pathogenic, 7% were probably pathogenic, 21% were of indeterminate pathogenicity, and 30% were nonpathogenic. Factors associated with pathogenic significance included pneumonia or bronchitis (87% of patients), predisposing respiratory or systemic conditions (62%), isolation from sputum, and pure isolation. Thirty-six percent of patients were < 5 years old, but only 9% of isolates from these patients were pathogenic or probably pathogenic, a finding that reflects the fact that nasal-swab and nasopharyngeal-aspirate sampling is a common practice. Isolates from older patients were more likely to be pathogenically significant. An assessment of the pathogenic significance of M. catarrhalis isolated from a patient in a community practice should take into consideration factors such as the patient's age, clinical illness, and underlying conditions; the presence of other organisms; and the source of the isolate.

Adolescent↗
PubMed1983

A simple oral antimicrobial regimen effective in severe chronic bronchial suppuration associated with culturable Haemophilus influenzae.

Three grams of amoxycillin administered twice daily for seven days, as an oral powder (Amoxil 3G sachets, Bencard) dispersed in water, to 17 patients with bronchiectasis resulted in striking clinical, spirometric and bacteriological improvement in 11 of 12 patients who were producing purulent sputum from which Haemophilus influenzae was cultured by a selective bacteriological technique (Roberts & Cole, 1980). In the five patients from whose sputum this organism could not be cultured, and in one from whom it could, there was no improvement. Untoward effects were limited to nausea in one patient and acceptability of the regimen by the remaining patients was unanimous. There was no evidence of accumulation of the drug in serum or sputum. The rapidity of effect and oral form of the treatment suggest that it may provide a simple out-patient regimen for chronic bronchial sepsis and severe purulent exacerbations of chronic bronchitis from which H. influenzae can be cultured.

Adult↗
PubMed1993

A simple chemical test to distinguish mycobacteria from other mycolic-acid-containing actinomycetes.

Two hundred and fifty-two representatives of the general Corynebacterium, Gordona, Mycobacterium, Nocardia, Rhodococcus and Tsukamurella were degraded by alkaline hydrolysis and their mycolic acids extracted as methyl esters following phase-transfer-catalysed esterification. When the mycolic acid methyl esters were treated with a mixture of acetonitrile and toluene all mycobacterial mycolates formed copious white precipitates whereas all but 5 out of the 106 non-mycobacterial mycolates remained in solution. The precipitated methyl mycolates and the dried soluble mycolates were compared by pyrolysis gas chromatography and silica gel thin-layer chromatography. On pyrolysis, the precipitated methyl mycolates from mycobacteria yielded fatty acid methyl esters with 20 to 26 carbon atoms whereas those from the remaining taxa produced shorter-chain esters. Mycobacteria and Tsukamurella paurometabola gave multispot mycolic acid patterns on thin-layer chromatography of their methyl esters whereas those from the remaining strains gave single spots. Our results indicate that Rhodococcus chlorophenolicus strains contain mycolic acids atypical of mycobacteria. It can be concluded that the mycolic acid precipitation test provides a simple and reliable way of distinguishing mycobacteria from all other prokaryotes, notably from other mycolic-acid-containing taxa.

Actinomycetales↗
PubMed2006

Patulibacter minatonensis gen. nov., sp. nov., a novel actinobacterium isolated using an agar medium supplemented with superoxide dismutase, and proposal of Patulibacteraceae fam. nov.

A novel Gram-positive bacterial strain, designated KV-614T, was isolated from a soil sample using an agar medium supplemented with superoxide dismutase. Based on 16S rRNA gene sequence analysis, it was found that the strain represented a novel deep-rooting lineage within the class Actinobacteria and clustered with yet-uncultivated bacteria from terrestrial environments and some unidentified strains isolated by unique methods. The most closely related established genus was Conexibacter (92.4% sequence similarity to Conexibacter woesei DSM 14684T). Cells of strain KV-614T were rod-shaped and motile with long flagella. The strain was catalase-positive, oxidase-negative and grew under aerobic conditions. The cell-wall peptidoglycan contained meso-diaminopimelic acid as the diagnostic diamino acid and alanine and glutamic acid. The peptidoglycan acyl type was acetyl. The only detected isoprenoid quinone was demethylmenaquinone with seven isoprene units (DMK-7). Mycolic acids were not detected. The predominant cellular fatty acid was omega9c-octadecenoic acid (C18:1omega9c). Minor components were 12-methyl tetradecanoic acid (anteiso-C15:0) and 14-methyl hexadecanoic acid (anteiso-C17:0). The DNA G+C content was 72 mol%. On the basis of phenotypic and genotypic characteristics, it is proposed that strain KV-614T represents a new genus and a novel species, Patulibacter minatonensis gen. nov., sp. nov., in the class Actinobacteria. The type strain is KV-614T (=NRRL B-24346T=JCM 12834T=NBRC 100761T). The creation of the family Patulibacteraceae fam. nov. is proposed to encompass the genus Patulibacter gen. nov.

Actinobacteria↗
PubMed2005

Evaluation of commercial kits for the identification of Neisseria gonorrhoeae.

Eight identification methods were evaluated against 100 isolates of Neisseria gonorrhoeae and 21 non-gonococcal Neisseria strains. The methods examined included four commercial biochemical kits, API NH, RapID NH, Gonochek II and Neisseria Preformed Enzyme Test (PET), three immunological kits, Phadebact Monoclonal GC test, GonoGen II and MicroTrak, and one in-house carbohydrate-utilization method, cystine trypticase agar (CTA) sugars. The percentage of isolates unambiguously identified as N. gonorrhoeae by each of the methods was as follows: API NH, 66 %; RapID NH, 64 %; GonoChek II, 66 %; Neisseria PET, 66 %; Phadebact Monoclonal GC OMNI test, 99 %; GonoGen II, 100 %; MicroTrak, 100 %; and CTA sugars, 96 %. The low sensitivity of the biochemical kits for the identification of N. gonorrhoeae was due to a lack of the enzyme proline iminopeptidase (Pip) in 34 % of the isolates examined. All the biochemical kits utilized the presence of this enzyme as a marker for N. gonorrhoeae. The Phadebact Monoclonal GC kit, GonoGen II, MicroTrak, CTA sugars and the API NH kit all exhibited high specificity, but non-gonococcal Neisseria were misidentified as N. gonorrhoeae using RapID NH (two strains), Gonochek II (11 strains) and Neisseria PET (11 strains). Whilst the isolates examined in this study may not be truly representative, they do indicate that N. gonorrhoeae isolates lacking the enzyme Pip can give anomalous results when using commercially available biochemical tests and that some non-pathogenic Neisseria species are still being misidentified using some biochemical kits. This further reinforces the recommendation that any dubious biochemical result should be confirmed with an immunological test.

Bacterial Typing Techniques↗
PubMed1991

A dot-immunobinding assay for the laboratory diagnosis of tuberculous meningitis and its comparison with enzyme-linked immunosorbent assay.

In an attempt to establish an alternative to standard bacteriological methods in the laboratory diagnosis of tuberculous meningitis (TBM), a simple dot-immunobinding assay (Dot-Iba) was standardized to detect Mycobacterium tuberculosis antigen 5 and antimycobacterial antibody in cerebrospinal fluid (CSF) specimens of patients with TBM. Sensitivity and specificity of Dot-Iba was compared with conventional enzyme-linked immunosorbent assay (ELISA) and standard bacteriological techniques. The Dot-Iba showed excellent correlation with indirect ELISA for the detection of antimycobacterial antibody in CSF and showed 60% sensitivity and 100% specificity in culture-negative patients with TBM. However Dot-Iba was less sensitive for the detection of antigen 5 in CSFs and showed false negative results (60%) in culture-positive patients with TBM.

Antibodies, Bacterial↗
PubMed2006

Carpegen real-time polymerase chain reaction vs. anaerobic culture for periodontal pathogen identification.

BACKGROUND/AIMS: The aim of this study was to compare two methods of microbiological diagnosis, anaerobic bacterial culture and real-time polymerase chain reaction (PCR), for the detection of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Tannerella forsythia, Fusobacterium nucleatum, and Treponema denticola. METHODS: Seventy-two samples were collected from 18 patients who were suffering from aggressive periodontitis. The data obtained were compared for the two methods. RESULTS: The results obtained with real-time PCR were different from those obtained with bacterial culture. The detection differences were 3% for A. actinomycetemcomitans, 8.33% for P. intermedia, and 12.5% for F. nucleatum. However, the differences for P. gingivalis and T. forsythia were 51.39% and 36.11%, respectively. No comparison was possible for T. denticola because it cannot be identified in culture. The variations found were the result of the better detection level (10(2) pathogens) of the PCR probe. Unlike bacterial culture, PCR allows the detection of T. denticola, which does not forming colonies and is oxygen sensitive. For F. nucleatum, T. forsythia and P. gingivalis, the real-time PCR technique was more sensitive than culture. CONCLUSION: Good results were obtained with the real-time PCR technique for the six periopathogens targeted. This method seems to be indicated for its simplicity, rapidity and reproducibility but it cannot analyze data for an antibiotic susceptibility test. The periodontist must therefore choose one of these two methods according to his specific clinical objective: to obtain rapid, specific detection even with weak initial concentrations (but for targeted periopathogens only) or to be non-specific and analyze the pathological activity with an antibiogram.

Aggregatibacter actinomycetemcomitans↗