Isolation of strains of a new ecological variant of Staphylococcus aureus from asses

47 coagulase-positive staphylococcal strains were isolated from the nasal smears of 175 healthy donkeys. In accordance with the schemes of Akatov--Devriese and Mayer-Witte--Akatov, 10.6% of the cultures were classified with the coagulase-positive species S. hyicus and 89.3%, with the species S. aureus. Out of S. aureus strains, 11.9% were found to have the characteristics of ecovar hominis, while 16.2% of the cultures could not be classified with definite ecovars. Most of the strains (71.4%) were found to differ from the known ecovars of S. aureus in their biological properties. For this reason, the above strains were classified with the new ecovar asinae. The authors propose to make the existing S. aureus identification scheme (the scheme of Mayer-Witte--Akatov) more complete by adding the tests for hyaluronidase and phosphatase.     

Phage typing of the coagulase-positive staphylococci isolated from various species of animals

More than 200 coagulase-positive strains of animal origin have been studied by means of Staphylococcus aureus typing phages, belonging to two international sets and intended for typing staphylococci isolated from large cattle and humans, and experimental "chicken" phage A 1591. Among S. aureus strains the cultures isolated from swine, cows, chickens, and belonging to biotypes B1, C1, B2, respectively, have been mostly (in 78.5-90.0% of cases) determined by phage typing. The strains belonging to one biotype have proved to be sensitive predominantly to the same phages. In this connection further differentiation of staphylococci within individual biotypes by means of the phages used in these experiments seems to be impracticable. S. intermedius strains have been found to be completely resistant to the above phages, which confirms that S. intermedius is rightly considered to be an independent species of coagulase-positive staphylococci.     

Resistance to antibiotics and heavy metal salts of coagulase-positive staphylococci belonging to different biological types (ecovars)

A total of 189 strains of S. aureus isolated from cows, sheep, swines, poultry, monkeys, rabbits, foxes, and humans and 23 strains of S. intermedius isolated from minks and sables were studied. The staphylococci belonged to different biological types (according to the Hajek-Marsalek's scheme) and ecovars (according to the Meyer-Witte's scheme). The strains were studied with respect to their resistance to 10 antibiotics (benzylpenicillin, streptomycin, tetracycline, levomycetin, erythromycin, oleandomycin, neomycin, kanamycin, monomycin, and novobiocin), mercuric chloride and cadmium sulfate. As a whole the frequency of resistance to the above preparations among the staphylococci of the animal origin was not high. Differences in the frequency and range of the resistance between strains belonging to different biological types (ecovars) were shown. The highest number of the resistant cultures was detected among the strains of the biological type E (ecovar canis) and atypical strains of S. intermedius isolated from the minks. The least number of the resistant cultures was detected among the strains of the biological type C1 (ecovar bovis) isolated from the cows. It was found that almost all strains of S. intermedius were resistant to cadmium sulfate. This may be used as an additional characteristic of the species.     

Characterization of coagulase-positive staphylococci isolated from free-living birds.

A total of 129 coagulase-positive staphylococcal strains were isolated from the nasopharyngeal region of free-living birds--81 (16%) from 501 birds of prey, 29 (25%) from 117 water birds, and 19 (2%) from 937 pheasants. Staphylococcus aureus and Staphylococcus intermedius were identified in 64 (79%) and 17 (21%) strains from birds of prey, in 1 (3%) and 28 (97%) strains from water birds, and in 4 (21%) and 15 (79%) strains from pheasants, respectively. Of the total number of the 69 S.aureus strains 45 (65%) could be biotyped. Biotype D prevailed in the strains from birds of prey. Among all the 60 S.intermedius strains 41 (68%) biotype 1 and 19 (32%) biotype 3 strains could be recognized. Biotype 1 predominated in strains from water birds and pheasants, while biotype 3 in strains from birds of prey. Resistance to antibiotics was recorded in 8 (12%) S.aureus and 5 (8%) S.intermedius strains only. Fifty-six (81%) of the 69 S.aureus strains could be typed with human phages, 30 (44%) with bovine and 41 (51%) with chicken phages. It is evident that the host range of Shimizu's (CH) phages involves not only S.aureus from chicken but also from any other birds. None of these strains was typable with canine phages. Out of the 60 S.intermedius strains 45 (75%) were lysed with Blouse and Meekins' canine phages. When human, bovine, and chicken phages were used, all the 60 strains were completely resistant.     

Serological characteristics of coagulase-positive staphylococci isolated from man and animals

A simplified method allowed Staphylococcus aureus, Staph. intermedius and coagulase-positive Staph. hyicus subsp. hyicus isolated from humans, dogs, monkey, sheep, poultry, rabbits, giant rats (Cricetomys gambianus) and other animals to be serotyped. The nine coagulase-positive staphylococcal strains of human origin possessed thermolabile and thermostable agglutinogens. Two strains of Staph. intermedius of human and canine origins examined had agglutinogen K1K2. The three Staph. aureus strains isolated from African giant rats (Cricetomys gambianus) had agglutinogens a5 and P common to them. The Staph. aureus strain isolated from a monkey belonged to serotype b1, c1, o and the caprine strain of Staph. hyicus subsp. hyicus was serotype a5, c1.     

Serological characteristics of coagulase-positive staphylococci isolated from man and animals

A simplified method allowed Staphylococcus aureus, Staph. intermedius and coagulase-positive Staph. hyicus subsp. hyicus isolated from humans, dogs, monkey, sheep, poultry, rabbits, giant rats ( Cricetomys gambianus ) and other animals to be serotyped. The nine coagulase-positive staphylococcal strains of human origin possessed thermolabile and thermostable agglutinogens. Two strains of Staph. intermedius of human and canine origins examined had agglutinogen K₁K₂. The three Staph. aureus strains isolated from African giant rats ( Cricetomys gambianus ) had agglutinogens a₅ and P common to them. The Staph. aureus strain isolated from a monkey belonged to serotype b₁, c₁, o and the caprine strain of Staph. hyicus subsp. hyicus was serotype a₅, c₁.     

Frequency of the isolation of staphylococci from domestic animals and strain identification

Staphylococci occur in donkeys more frequently than in other animals, and only from donkeys coagulase-negative staphylococci, characteristic of humans (S. hominis, S. capitis, S. cohnii), were isolated. Least frequently staphylococcal carrier state was registered in cats; in these animals only coagulase-negative strains were found to occur. From 30 donkeys coagulase-positive staphylococci belonging to 47 S. aureus strains were isolated. These strains differed from known ecological variants in their biological properties, thus suggesting the existence of S. aureus ecovar specific for donkeys. These strains did not coagulate human, bovine and ovine plasma, but coagulated rabbit plasma in 100% of cases and donkey plasma only in 53% of cases; at the same time they relatively often produced delta hemolysin, rarely phosphatase and hyaluronidase and never fibrinolysin. These strains were typed by KPC phages, mainly 116 and 117.     

Characteristics of staphylococci isolated from man, poultry and some other animals

Of 281 strains of staphylococci isolated from man and animals 36 (12.8%) were coagulase-positive and 245 (87.2%) were coagulase-negative. Staphylococcus aureus and Staph. intermedius were the commonest coagulase-positive staphylococci isolated from the hosts examined. Of the 20 strains that remained unclassifiable, 14 were isolated from sheep and goats.     

Characteristics of staphylococci isolated from man, poultry and some other animals

Of 281 strains of staphylococci isolated from man and animals 36 (12–8%) were coagulase-positive and 245 (87–2%) were coagulase-negative. Staphylococcus aureus and Staph. intermedius were the commonest coagulase-positive staphylococci isolated from the hosts examined. Of the 20 strains that remained unclassifiable, 14 were isolated from sheep and goats.     

A Comparison of Methods and the Validity of Deoxyribonuclease Tests for the Characterization of Staphylococci Isolated from Animals

Strains isolated from pigeons belonging to the coagulase-positive species Staphylococcus intermedius , coagulase-negative Staph. hyicus subsp. chromogenes strains from cattle and pigs, and Staph. aureus strains from poultry, gave weakly positive reactions in DNase plate culture tests and heat-resistant DNase tests. Staph. aureus and Staph. intermedius strains from other sources and coagulase-negative and coagulase-positive Staph. hyicus subsp. hyicus strains reacted strongly in these tests. A standardized plate culture test procedure is proposed and the use of DNase tests in the identification of staphylococci isolated from animals is discussed.     

Comparative Characterization and Biotyping of Staphylococcus aureus Isolates from Human and Bovine Sources

One Hundred and ten alpha and/or delta-haemolytic isolates (collection 1), 50 beta haemolytic isolates (collection 2) from bovine mastitis, and 100 previously phage-typed alpha- and delta-haemolytic isolates (human collection) og Staphylococcus aureus (S. aureus) were tested and biotyped according to the scheme of Hajek & Marsalek (1971). Among collection 1 isolates, 85 (77.3 %) belonged to the human biotype A (human source). Twenty two (20 %) designated as non-allotted strains, possessed characteristics of both animal and human sources. The remaining 3 isolates (2.7 %) in this collection belonged to biotype C (animal source). All collection 2 isolates which were used as control strains for animal sources, belonged to biotype C. The human collection that contained 100 phage-typed haemolytic isolates (representing all human phage groups) were used as a control for the human source. Irrespective of their phage group, these strains predominantly produced alpha and/or delta haemolysins and belonged to the human biotype A. This study also recommended the use of a combined plasma crystal violet agar medium for the presumptive identification of S. aureus biotypes.     

Staphylococci in the microbiocenosis of the skin of the hands]

The skin autoflora on the pad of a forefinger and the back and palm of a hand was studied in 40 healthy males aged 18-60 years by the modified washing and scraping method of P. Williamson and A. Kligman. 638 cultures of aerobic microorganisms, including coccal (55.3%) and bacilliform (44.7%) microbes, were isolated. In 6 persons (15%) coagulase-positive staphylococci were detected. Out of 10 coagulase negative species of this genus, S. epidermidis, S. saprophyticus and S. warneri occurred most frequently on the skin of hands. The highest density of bacterial populations (10.970 +/- +/- 1.845 cells/sq. cm) was registered on the back of hands, the surface of palms was found to have somewhat lower density (8.679 +/- 1.282 cells/sq. sm) and the skin of forefingers, the lowest density of bacterial populations (6.878 +/- +/- 1.137 cells/sq. sm). 17.5% of examined persons were found to be carriers with S. aureus isolated from their nasal mucosa. S. aureus isolated from the skin surface and the nasal cavity of different persons belonged to different phage variants, but S. aureus isolated from the nasal cavity and the skin of the same person belonged to one phage variant.     

Antagonistic activities of coagulase-positive staphylococci

Antagonistic activities were investigated by Frédérioq's plate method in 1,014 coagulase-positive staphylococcal strains of different species and origins. Staphylococcin effect was demonstrated in 12 (2%) of the 559 Staphylococcus aureus strains, in 51 (18%) of the 283 S. intermedius strains, and in 1 (3%) of the 36 S. hyicus subsp. chromogenes strains. Lysostaphin was identified in the 15 (5%) S. intermedius strains. In addition, heat-stable bacteriostatic agent was detected in 45 (33%) and heat-labile bacteriolytic agent in 7 (5%) of the 136 S. hyicus subsp. hyicus strains. An attempt was made at antagonistic activity typing in all of the active staphylococcal strains.     

Identification of enterotoxigenic staphylococci from sheep and sheep cheese

The total of 127 Staphylococcus aureus strains obtained from sheep and sheep cheese were examined for their biochemical activities, biotypes, phage patterns, and ability to produce enterotoxins. Of the 83 staphylococcal strains isolated from animals 77 (93%) were classified as the C biotype. Of this group of sheep-adapted strains, 61 (79%) were sensitive to phage 78, and 46 (60%) produced enterotoxin C exclusively. The three isolated belonging to the A biotype produced enterotoxin D, and two of the three unclassifiable strains produced enterotoxin A. Of the 44 staphylococcal strains isolated from sheep cheese, there were 37 (84%) identified as the C biotype. From this series, 31 (84%) strains were lysed with phage 78, 6 (16%) strains produced enterotoxin C, and 1 strain produced enterotoxin A. One of the six strains determined as the A biotype produced enterotoxin D. C biotype strains, especially of ovine origin, are an exception among animal staphylococci, because a large number of them are enterotoixgenic. The C antigenic type is the most usual of the known enterotoxins in staphylococci of animal provenance.     

Enterotoxin production in different Staphylococcus aureus biotypes isolated from food and meat plants.

Strains of Staphylococcus aureus isolated in Belgium and Za?re from food and from various sources in the meat industry were biotyped, phage typed and tested for staphylococcal enterotoxin (SE) production. Thirty of the 185 strains examined produced one or more SE, and 23 of these belonged to the human biotype. Most SE-positive strains belonged to phage groups III and Mixed, or were not typable. None of the poultry-like biotype strains, which were frequent in nasal carriers among workers in meat plants as well as in minced meat, produced enterotoxins. Avian biotype strains similarly were negative.     

Enterotoxin production in different Staphylococcus aureus biotypes isolated from food and meat plants

Strains of Staphylococcus aureus isolated in Belgium and Zaïre from food and from various sources in the meat industry were biotyped, phage typed and tested for staphylococcal enterotoxin (SE) production. Thirty of the 185 strains examined produced one or more SE, and 23 of these belonged to the human biotype. Most SE-positive strains belonged to phage groups III and Mixed, or were not typable. None of the poultry-like biotype strains, which were frequent in nasal carriers among workers in meat plants as well as in minced meat, produced enterotoxins. Avian biotype strains similarly were negative.     

RAPD-PCR analysis of Staphylococcus aureus strains isolated from bovine and human hosts

Staphylococcus aureus is one of the most important pathogens in humans and animals. In this study eighty strains were analyzed by RAPD-PCR to assess the genetic relationship between S. aureus isolates from bovine and human hosts. Results were compared with those obtained by biotyping. Fifty-two percent of the S. aureus isolates belonged to a host specific biotype (human, bovine and poultry). Bovine and human ecovars were the most prevalent. Dendrogram obtained by RAPD results showed that all the isolates clustered into eleven groups (A-K) at a relative genetic similarity of less than 30% when analyzed with the three primers. Group A clustered 95% of the human host isolates and the remaining groups (B-K) clustered the bovine host isolates. Principal coordinate analysis also showed that the isolates could be arbitrarily divided into two groups, bovine and human, by the second coordinate. Only 9 isolates (11%) were not clustered into these groups. The genetic diversity among the S. aureus isolates from bovine hosts is relatively low compared to that of isolates from human hosts. There were no statistically significant differences among isolated from bovine and human hosts. This study shows that RAPD-PCR assayed with three primers can be successfully applied to assess the genetic relationship of S. aureus isolates from different hosts.     

Interspecies lysogenization in staphylococci: transfer of bacteriophage converting enterotoxin A from a clinical strain of Staphylococcus aureus to Staphylococcus intermedius

The ability of lysogenization was examined of 50 S. intermedius strains and of 77 strains belonging to 14 different species of coagulase-negative staphylococci using 8 enterotoxin A converting bacteriophages isolated from S. aureus. All the examined bacteriophages showed lytic activity against at least 1 of 11 susceptible strains of S. intermedius to them. Lytic activity towards coagulase-negative staphylococci was observed for 6 of 8 examined bacteriophages. Two bacteriophages were active against 1 of 9 examined S. capitis strains, one against 1 of 11 examined S. haemolyticus strains, four against 1 of 6 examined S. lugdunensis strains, three against 1 of 6 examined S. warneri strains and one against 1 of 5 examined S. xylosus strains. Lysogenization with bacteriophage f421-1 able to convert positively enterotoxin A and staphylokinase and negatively beta-haemolysin of one S. intermedius strain was successful. S. intermedius lysogenized with phi 421-1 was able to produce both enterotoxin A and staphylokinase and lost ability to produce beta-haemolysin. Our results showed a broad lytic spectrum and interspecies host range of some S. aureus bacteriophages and the ability of interspecies transfer of bacteriophages between S. aureus and S. intermedius.     

PCR detection of staphylococcal enterotoxin genes in Staphylococcus spp. strains isolated from meat and dairy products. Evidence for new variants of seG and seI in S. aureus AB-8802

AIMS: Evaluation of the occurrence of most known staphylococcal enterotoxin (SE) genes, egc (enterotoxin gene cluster) and TSST1 (toxic shock syndrome toxin 1) gene in both coagulase-positive (CPS) and coagulase-negative (CNS) staphylococcal strains isolated from meat and dairy products. METHODS AND RESULTS: Specificity and reliability of the PCR detection methods used were ascertained by using nine reference strains of Staphylococcus (S. aureus) harbouring SE genes (seA to seE; seG, seH, seI, seM, seJ, seN and seO) and egc (containing the following sequence of genes: seO, seM, seI, phient1, phient2, seN and seG). Of 109 wild Staphylococcus spp. strains analysed, only 11 S. aureus strains were SE and/or TSST1 PCR-positive. The last 11 strains also appeared to harbour the egc. Restriction endonuclease analysis of part of the egc of both reference and wild strains showed that different variants of the egc exist. Moreover, nucleotide sequences of seG and seI indicate that the egc of the strain AB-8802 is characterized by the presence of variants of these enterotoxins (seGv and seIv). CONCLUSIONS: The occurrence of SE genes in CNS and other non-S. aureus species isolated from Napoli-type salami, raw water buffalo milk and natural whey cultures used for mozzarella cheese manufacturing is very rare. SIGNIFICANCE AND IMPACT OF THE STUDY: During this study it was shown that at least five different egc may exist in S. aureus. A thorough study of egc polymorphism should provide further insight into the phylogenetics of the egc.     

Biological characteristics of Staphylococcus aureus isolated from nude mice

The characteristics of 50 strains of Staphylococcus aureus isolated from BALB/c nude mice (nu/nu, nu/+) with or without subcutaneous abscesses [13] were examined. All the 50 strains belonged to biotype B according to the classification by Hájek and Marsálek. All of them were phage typable, showing a single phage pattern of 52A/79/47/53/77/83A/85. The coagulase type was classified as VII. All of the 50 strains were highly sensitive to penicillin, methylphenylisoxazolyl penicillin, erythromycin, spiramycin, lincomycin, chloramphenicol, tetracycline, kanamycin, gentamicin and cephaloridine, but were resistant to sulfisoxazole. Two S. aureus strains isolated from the nostril and finger of one person working in the mouse colony were identified as the same biotype as the murine strains but different in phage type, coagulase type and drug resistance pattern.