Rapid test for the serological separation of staphylococci from micrococci

A simple test for the serological separation of staphylococci from micrococci is described, which is based on the quite different cell wall peptidoglycan structures of these two genera. Antisera to (pentaglycyl-epsilon-amino-n-hexanoic acid)20-albumin agglutinated without exception all staphylococci and gave no positive reaction with micrococci or other bacterial cells. To obtain a good reaction, it was necessary to extract the cells with hot trichloroacetic acid for 30 min. Antisera to (tri-L-alanyl-epsilon-amino-n-hexanoic acid)22-albumin reacted strongly with micrococci containing oligo-L-alanine bridges in their peptidoglycan, but did not agglutinate staphylococci or other bacteria lacking alanine interpeptide bridges.     

Rapid test for the serological separation of staphylococci from micrococci.

A simple test for the serological separation of staphylococci from micrococci is described, which is based on the quite different cell wall peptidoglycan structures of these two genera. Antisera to (pentaglycyl-epsilon-amino-n-hexanoic acid)20-albumin agglutinated without exception all staphylococci and gave no positive reaction with micrococci or other bacterial cells. To obtain a good reaction, it was necessary to extract the cells with hot trichloroacetic acid for 30 min. Antisera to (tri-L-alanyl-epsilon-amino-n-hexanoic acid)22-albumin reacted strongly with micrococci containing oligo-L-alanine bridges in their peptidoglycan, but did not agglutinate staphylococci or other bacteria lacking alanine interpeptide bridges.     

A simple and cost-effective cover-glass test for the differentiation between staphylococci and micrococci in clinical laboratory

A cover-glass placed on a heavily inoculated culture plate clearly differentiates facultatively anaerobic staphylococci growing underneath the cover-glass after overnight incubation from nongrowing aerobic micrococci. Even if there are some exceptions, all medically significant staphylococci can grow in the test. Thus, the test provides a cost-effective and highly specific tool for separation of both genera which fundamentally differ in their pathogenicity.     

Temporal study of the staphylococci and micrococci of normal infant skin

Staphylococcus and Micrococcus populations were collected from the healthy skin of 10 infant subjects. Infants were sampled from 1 day to 32 weeks of age. Species were characterized by approximately 30 different morphological, physiological, and biochemical characters. Staphylococci were the predominant inhabitants of normal skin, whereas micrococci were found only occasionally in this environment. Staphylococcus epidermidid, S. haemolyticus, and S. hominis were the predominant and persistent staphylococci. These species constituted a high percentage of the total aerobic bacterial flora of infant skin. Micrococcus luteus and M. kristinae were the prevalent micrococci found on infant skin. Only limited correlation between Staphyloccus and Micrococcus populations and infant age or body area sampled was indicated by this study.     

Temporal study of the staphylococci and micrococci of normal infant skin.

Staphylococcus and Micrococcus populations were collected from the healthy skin of 10 infant subjects. Infants were sampled from 1 day to 32 weeks of age. Species were characterized by approximately 30 different morphological, physiological, and biochemical characters. Staphylococci were the predominant inhabitants of normal skin, whereas micrococci were found only occasionally in this environment. Staphylococcus epidermidid, S. haemolyticus, and S. hominis were the predominant and persistent staphylococci. These species constituted a high percentage of the total aerobic bacterial flora of infant skin. Micrococcus luteus and M. kristinae were the prevalent micrococci found on infant skin. Only limited correlation between Staphyloccus and Micrococcus populations and infant age or body area sampled was indicated by this study.     

A separation of staphylococci and micrococci based on serological reactivity with antiserum specific for polyglycerophosphate.

A serological reaction with the antiserum against heterophile polyglycerophosphate (PGP) was evaluated for genus level differentiation among strains of Staphylococcus and Micrococcus-Sarcina spp.. Hot saline extracts from whole cells of Staphylococcus spp. strongly reacted with the PGP antiserum, whereas those of Micrococcus-Sarcina spp. did not. Likewise, phenol-water extracts from whole cells of Micrococcus-Sarcina spp. were not reactive with the PGP antiserum, although the extracts of staphylococcal cells again gave a strong reaction with the antiserum. This study indicates that extracts from Micrococcus-Sarcina spp. have no antigen reactive with the PGP antiserum and can thus be differentiated from extracts of Staphylococcus spp. which react strongly with the PGP antiserum.     

Rapid distinction between Leptospira interrogans and Leptospira biflexa by PCR amplification of 23S ribosomal DNA

Bacterial specific primers were used to amplify 23S rRNA genes from a representative strain from each of the 23 serogroups of the pathogenic Leptospira interrogans and 8 strains from 6 serogroups of the non-pathogenic Leptospira biflexa. Only regions of extreme variability, which had been identified on the basis of homology-based search of all the 23S rRNA sequences available in GenBank database, were sequenced from the amplified products. PCR primers that had the potential to distinguish L. interrogans from L. biflexa species were designed from the derived sequences and a sensitive PCR protocol developed. The PCR method enabled the differentiation of the 59 strains of the 23 serogroups of L. interrogans from the 8 strains of 6 serogroups of L. biflexa. Further investigation by 16S rDNA sequencing of two strains of L. interrogans, which gave unexpected PCR results, provided evidence that they had been misclassified and hence we propose to reassign them to L. biflexa.     

Molecular distinction between arteries and veins

The vertebrate vascular system is essential for the delivery and exchange of gases, hormones, metabolic wastes and immunity factors. These essential functions are carried out in large part by two types of anatomically distinct blood vessels, namely arteries and veins. Previously, circulatory dynamics were thought to play a major role in establishing this dichotomy, but recently it has become clear that arterial and venous endothelial cells are molecularly distinct even before the output of the first embryonic heartbeat, thus revealing the existence of genetic programs coordinating arterial-venous differentiation. Here we review some of the molecular mechanisms involved in this process.The first two authors contributed equally to this work     

The distinction between transudates and exudates

Summary The first step in the diagnosis of pleural effusions is the distinction between exudates and transudates. The aim of this study was to evaluate the usefulness of various parameters for the differentiation of pleural exudates and transudates. We recorded clinical characteristics, final diagnoses, and measured pleural fluid and serum levels of albumin, protein, LDH, cholesterol, and bilirubin of 381 consecutive patients with pleural effusion. Seventy-one (23%) pleural effusions were transudates and 236 were exudates. As a single criterion, the pleural fluid to serum albumin ratio >0.5 was the most accurate parameter (88.4%). An albumin gradient of 12 g/l had an accuracy of 75% in the whole population but it detected 96% of transudative effusions in patients treated with diuretics. Light’s criteria and abbreviated Light’s criteria had similar accuracies, 87.8% vs. 88.2%, respectively. In conclusions, different alternatives can be used instead of Light’s criteria.     

Rapid method for detecting thermostable nuclease in staphylococci

A rapid test for the detection of staphylococcal thermostable nuclease (TNase) is described. The procedure consists of heat inactivation of solid cultures of staphylococci and microslide agar diffusion technique in toluidine blue agar containing deoxyribonucleic acid. Using this method the results are obtained about 1 d sooner than with the conventional method. Translated by I. Miler