Comparative study of "Micrococcus sp." strains CCM 168 and CCM 1405 and members of the genus Salinicoccus.

Two culture collection strains, CCM 168 and CCM 1405, previously assigned to the genus Micrococcus were shown by molecular chemical characterization to belong to the genus Salinicoccus. A more detailed comparison of the physiological and biochemical properties of these strains and comparison with the type strain of Salinicoccus roseus indicated high degrees of relatedness among the three strains. DNA-DNA hybridization studies confirmed the high degrees of relatedness. All of the data demonstrate quite clearly that strains CCM 168 and CCM 1405 are members of the species S. roseus.

Mercuric reductase in environmental gram-positive bacteria sensitive to mercury.

According to existing data, mercury resistance operons (mer operons) are in general thought to be rare in bacteria, other than those from mercury-contaminated sites. We have found that a high proportion of strains in environmental isolates of Gram-positive bacteria express mercuric reductase (MerA protein): the majority of these strains are apparently sensitive to mercury. The expression of MerA was also inducible in all cases. These results imply the presence of phenotypically cryptic mer resistance operons, with both the merA (mercuric reductase) and merR (regulatory) genes still present, but the possible absence of the transport function required to complete the resistance mechanism. This indicates that mer operons or parts thereof are more widely spread in nature than is suggested by the frequency of mercury-resistant bacteria.

Staphylococcus muscae, a new species isolated from flies.

A new coagulase-negative species of the genus Staphylococcus, Staphylococcus muscae, is described on the basis of the results of a study of four strains that were isolated from flies. 16S rRNA sequences of the type strains of S. muscae, Staphylococcus schleiferi, and Staphylococcus sciuri were determined and used, together with the corresponding sequences of Staphylococcus aureus and Staphylococcus epidermidis, for a comparative analysis. The new species is characterized taxonomically; this species is differentiated from the other novobiocin-susceptible staphylococci by its physiological and biochemical activities, cell wall composition, and levels of genetic relatedness. The type strain of this species is strain MB4 (= CCM 4175).

Identification of Staphylococcus and Micrococcus species with the STAPHYtest system.

A collection of 216 well-characterized strains of Staphylococcus, Micrococcus and Stomatococcus was examined by a commercially available STAPHYtest system (Lachema, Brno, Czechoslovakia). The results of STAPHYtest agreed with those of conventional tests. The STAPHYtest permitted a clear-cut separation of Staphylococcus from Micrococcus and Stomatococcus strains and correctly identified 104 of 145 (72%) Staphylococcus strains after 24 h of incubation. However, it allowed the identification only of 19 of 29 validly published Staphylococcus species. The STAPHYtest proved to be a simple and rapid system for the separation of staphylococci from micrococci and for the identification of most frequent clinically significant staphylococci.

International collaborative evaluation of the ATB 32 staph gallery for identification of the Staphylococcus species.

This international collaborative study evaluates a new system (ATB 32 Staph) for the identification of staphylococci taking into account the new novobiocin-sensitive and -resistant species reported. This study involved eight laboratories and 792 strains were tested. The reproducibility obtained for the cumulative results of the inter- and intra-laboratory tests was more than 90%. For 713 strains relevant of a species 95.5% were correctly identified by the system. Eight strains (1.2%) were misidentified and 24 strains (3.3%) were not identified. For 79 strains initially considered as not-classified, 62% were identified at the species level by the new system. The newer ATB 32 Staph gallery is a performant and useful method for routine identification of the currently described staphylococci species from clinical and animal origin.

[Typing of skin staphylococci using the commercial identification system Staphy-Test]. / Die Typisierung von Hautstaphylokokken mittels des kommerziellen Identifikationssystems STAPHYtest.

The authors examined 150 strains of S. aureus and 180 strains of S. epidermidis isolated from different dermatoses. The determination of S. aureus and S. epidermidis was based on common routine tests as plasmacoagulase, production of hemolysin, acid production from mannitol and production of pigment. This determination was verified with the aid of a new identification system STAPHYtest. The STAPHYtest confirmed the previous diagnosis of S. aureus in 60.66% and that of S. epidermidis in 31.66% of strains only. The remaining strains were identified by means of STAPHYtest as S. simulans, S. xylosus, S. hominis, S. haemolyticus, S. warneri, S. auricularis, S. sciuri and Micrococcus sp. The authors discuss the importance of an curate identification of skin staphylococci by means of STAPHYtest for taxonomic purposes and for classification of staphylococci influence on different dermatoses.

New medium for detection of esterase and gelatinase activity.

A new medium was developed for detecting esterase and gelatinase activities in aerobic and facultatively anaerobic bacteria. The new medium was tested with various strains of bacteria and the results showed agreement between the reactions in the new medium and those obtained by conventional techniques. The new medium is more economical and may be used for a rapid differentiation of Serratia, Aeromonas and Vibrio species from biochemically similar bacteria.

Moderately halophilic gram-positive cocci from hypersaline environments.

38 strains of moderately halophilic Gram-positive, catalase-positive cocci were isolated from saline soils and the ponds of a solar saltern in Alicante (Spain). They were divided into three biochemically distinct groups. On the basis of the characteristics investigated the 25 strains of group I corresponded to Planococcus halophilus; the ten strains of group II were morphologically and biochemically similar to the species Sporosarcina halophila; group III, comprising three strains, differed strikingly from the previous groups in certain biochemical tests. These strains differed from the planococci and micrococci so far described and were tentatively designated as Planococcus sp. The results have shown that moderately halophilic Gram-positive, motile cocci, are frequent inhabitants of hypersaline environments.

Phosphatase activity of aerobic and facultative anaerobic bacteria.

1115 strains of aerobic and facultatively anaerobic bacteria were tested for phosphatase activity by a conventional plate method and a microtest. The microtest was devised to allow results to be read after 4 h cultivation. Phosphatase activity was found in wide range of species and strains. Besides staphylococci, where the test for phosphatase is successfully used, it may be applied as one of the valuable tests for the differentiation of the following species: Bacillus cereus, B. licheniformis, Aeromonas spp., Vibrio parahaemolyticus, Actinobacillus spp., Pasteurella spp., Xanthomonas spp., Flavobacterium spp., Alteromonas putrefaciens, Pseudomonas maltophilia, Ps. cepacia, and some other species of Pseudomonas. The species which gave uniformly negative phosphatase reaction were as follows: Staph. saprophyticus, Acinetobacter calcoaceticus, Alcaligenes faecalis, and Bordetella bronchiseptica.

The fine structure of Micrococcus radiophilus and Micrococcus radioproteolyticus.

The radiation resistant bacteria Micrococcus radiophilus and M. radioproteolyticus were studied by thin sectioning and freez-etching techniques and the two species were found to be similar in the fine structure. The only significant difference was in the appearance of the surfaces of the cell walls in freeze-etched preparations. Since the two species, together with M. radiodurans, possess a unique cell wall structure and a cell wall peptidoglycan, which is different from that of other micrococci and Gram-positive cocci, it is recommended that they be reclassified into a new genus.

A comparison of tests for nitrate reduction.

504 strains of different bacteria have been tested for nitrate reduction by a conventional method and two microtests. A quick microtest for nitrate reduction is suggested allowing to read results after 1 hr cultivation. Nitrate reduction is a valuable test particularly for the species differentiation of the genera Bacillus, Micrococcus, Pseudomonas, Alcalignes, Moraxella, and other ones.