Four methods for the species identification of coagulase-negative staphylococci in the medical microbiology laboratory were compared with 444 consecutive isolates. The methods included (i) the reference method based on growth tests, (ii) API ID 32 Staph (bioMérieux), (iii) Staph-Zym (Rosco), and (iv) a rapid 4-h method developed in our laboratory (UZA method). The last method is based on the detection within 4 h of enzymatic activity of heavy bacterial suspensions in three substrate solutions (nongrowth tests). For 16.5% of the isolates some supplementary growth tests read after 24 h had to be added to the enzyme data for satisfactory identification. The reference method failed to identify four isolates. Of the 440 isolates identified by the reference method, API ID 32 Staph, Staph-Zym, and the UZA method correctly identified 419 (95.2%), 429 (97.5%), and 430 (97.7%) and misidentified 8 (1.8%), 4 (0.9%), and 1 (0.2%), respectively. Staphylococcus epidermidis, S. haemolyticus, S. lugdunensis, S. schleiferi, and S. capitis were identified with an accuracy of 98 to 100% by all the systems tested. S. capitis subsp. ureolyticus was not recognized by the API ID 32 system because the biochemical profiles for it are not yet included in the corresponding database. Whereas API ID 32 identified all 13 S. warneri isolates, both Staph-Zym and the UZA method missed 2 of these. S. hominis was identified with the least accuracy by the API ID 32 system (26 of 39 isolates), whereas the UZA and Staph-Zym methods identified 36 of the isolates belonging to this species. The UZA method did not identify any of the S. cohnii, S. xylosus, S. lentus, and S. sciuri strains, since it included no discriminatory tests for these species, because they are extremely rarely found in humans. Of all 440 isolates tested, the UZA method failed to identify 9 and misidentified 1 other. Eighty-one percent of the isolates were identified within 4 h and 97.7% were identified after 24 h, at considerably less expense than by the API ID 32 Staph and Staph-Zym methods.
The polymerase chain reaction (PCR) based on the selective amplification of a 530-bp fragment of the gene encoding the proline-rich antigen of Mycobacterium leprae was applied on sections of fixed or frozen biopsy samples from leprosy patients. A simple procedure for the extraction of DNA from M. leprae in clinical specimens that provided suitable template DNA for amplification was developed. When PCR was applied on frozen sections, positive amplification in samples from all untreated acid-fast bacillus (AFB)-positive patients and in samples from 56% of the untreated AFB-negative patients could be detected, while biopsy samples from patients with skin diseases other than leprosy were all PCR negative. With neutral Formalin-fixed biopsy samples, positive amplification in 92% of the samples from untreated AFB-positive patients and in 61% of the samples from untreated AFB-negative patients could be detected by PCR. Biopsy samples exposed to mercuric chloride or nonbuffered formaldehyde containing fixatives were not suitable for application of PCR. This PCR holds promise as a tool for studies on M. leprae infection.
Summary In 2 non-governmental organization projects in Bangladesh 244 new leprosy patients were classified in the field according to clinical criteria. Skin smears were taken at 4 standardized sites and at the most active peripheral lesion, where a biopsy was also taken.Comparison of the clinical field classification with the results of the skin smears and biopsies gives a sensitivity of 92· 1 % for the clinical criteria, but a specificity of only 41'3%. The skin-smear results, on the other hand, have a sensitivity of 88-4% and a specificity of 98·1 %.Thus, skin smears may contribute considerably to the operational classifica tion of leprosy patients under field conditions. Quality control of the peripheral laboratory is essential. Appropriate site selection for the smear taking will also contribute to increased performance. Analysis of the skin-smear results suggests that the policy of taking smears at standardized sites should be abandoned in favour of the earlobes and active peripheral lesions.According to WHO recommendations, 1 the operational classification of leprosy cases in paucibacillary (PB) and multi bacillary (MB) patients should be based on the bacter iological index, whereby the presence of acid-fast bacilli (AFB) at any single site is the criterion used fo r classification as MB. However, the validity of skin smear results has often been questioned, 2 -4 and many leprosy control programmes base their operational
Summary In 2 non-governmental organization projects 244 new leprosy patients in Bangladesh were classified in the field according to clinical criteria i.e. number of skin lesions and number of enlarged nerves.Comparison of these classification results with the results of skin smears and biopsies yielded a sensitivity (for detection of a MB case) of 92· 1 %, but the 'unconfirmed MB rate' amounted to 52·6%.In order to improve the reliability of the operational classification, several additional clinical criteria were investigated. It was found that neither the presence of anaesthesia in the skin lesions nor the presence of grade 2 disabilities or peripheral anaesthesia or voluntary muscle testing (VMT) impairment contributed to an improved classification. Counting the number of body areas showing signs of leprosy, which had proven very useful in other programmes, did not result in a more reliable classification in the 2 projects in Bangladesh.The presence of clinical signs of lepromatous leprosy, more specifically nodules or diffuse infiltration, could be a useful addition to the classification criteria. If the sensitivity must remain higher than 90%, the lowest 'unconfirmed MB rate' obtainable in Bangladesh, using clinical criteria only, is 46'4%, for a sensitivity of 91·0%. However, the inclusion of skin-smear results in the classification criteria could improve the sensitivity to 96·6% and lower the 'unconfirmed MB rate' to 40·3%. A reduction in MB overclassification will result in more efficient and more cost-effective leprosy control programmes.Many leprosy programmes rely on clinical criteria in order to classify the patients into paucibacillary (PB) and multibacillary (MB) groups. A first part of the present study l 'Il Correspondence: ALERT,
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