Evidence for a disseminated erythromycin resistance determinant mediated by Tn917-like sequences among group D streptococci isolated from pigs, chickens, and humans.

A total of 199 streptococci isolated from feces of healthy chickens, pigs, and beef cattle and 26 human clinical isolates were tested for resistance to kanamycin, streptomycin, tetracycline, erythromycin, and lincomycin. Of 66 isolates resistant to these antibiotics, 12 transferred one or more resistance traits by conjugation in broth. Erythromycin resistance (Emr) was transferred from 10 of the 12 successful donors.

Presence of Histamine in the Bluefish, Pomatomus saltatrix.

Consumption of bluefish ( Pomatomus saltatrix ) has been epidemiologically implicated and confirmed by laboratory analyses as a cause of scombroid food poisoning. An examination of marketable bluefish filets in the State of Connecticut found over 6.5% of the filets had histamine levels indicative of decomposition.

Disseminated tetracycline resistance in oral streptococci: implication of a conjugative transposon.

A DNA sequence specifying tetracycline resistance (Tcr) has been previously cloned from a clinical isolate of Streptococcus mutans designated U202 (J. A. Tobian and F.

Streptococcus faecalis R plasmid pJH1 contains an erythromycin resistance transposon (Tn3871) similar to transposon Tn917.

The R plasmid pJH1 contains a 5.1-kilobase transposon ( Tn3871 ) that mediates inducible resistance to erythromycin. Three AvaI digestion fragments from this transposon are identical in size to and homologous with three AvaI-derived fragments from the previously described erythromycin resistance transposon Tn917 .

A 2-mercaptoethanol tube agglutination test for diagnosis of Haemophilus pleuropneumoniae infection in pigs.

A 2-mercaptoethanol (2-ME) tube agglutination (TA) test has been developed as an alternative to the complement fixation (CF) test for the detection of antibodies to Haemophilus pleuropneumoniae, a causative agent of pleuropneumonia in pigs. Using sera from experimentally infected pigs, herds with confirmed H pleuropneumoniae infection, and from disease-free pigs, the specificity and the sensitivity of the 2-ME-TA test were investigated and results were compared with those obtained using the CF test. The TA test without 2-ME gave 100% nonspecific reaction.

Physical and genetic analyses of streptococcal plasmid pAM beta 1 and cloning of its replication region.

Plasmid pAM beta 1, originally isolated from Streptococcus faecalis DS5, mediates resistance to the MLS (macrolide, lincosamide, and streptogramin B alpha) group of antibiotics. A restriction endonuclease map of the 26.5-kilobase (kb) pAM beta 1 molecule was constructed by using the enzymes AvaI, HpaII, EcoRI, PvuII, Kpn1, BstEII, HpaI, HhaI, and HindIII.

Pathogenicity of Eikenella corrodens in humans.

Eikenella corrodens is resident flora of the normal adult human oral cavity. Four cases of verified infection and previous case reports of infections caused by this organism were reviewed and analyzed. Rarely has this bacillus been found as the sole isolate to initiate infection in the host with normal immune status.

Myosin isozymes in avian skeletal muscles. II. Fractionation of myosin isozymes from adult and embryonic chicken pectoralis muscle by immuno-affinity chromatography.

Chicken pectoralis consists primarily of large white fibres, which react exclusively with antibodies prepared against adult fast myosin. There is, however, a small region of uniformly red fibres which responds to antibodies against adult slow myosin as well as adult fast myosin. The myosin extracted from this red region is also heterogeneous as shown by the presence of both slow and fast light chains.

Myosin isozymes in avian skeletal muscles. I. Sequential expression of myosin isozymes in developing chicken pectoralis muscles.

Myosin has been purified from chicken pectoralis muscle at various stages of development, from 10 days' incubation to approximately 10 months after hatching. Embryonic myosin from the earliest stage showed a high level of ATPase activity, similar to that obtained for adult pectoralis myosin. Two-dimensional peptide mapping of partial chymotryptic digests showed, however, that is heavy chain is quite different from that of adult fast myosin.

Genetic, molecular, and functional analysis of Streptococcus faecalis R plasmid pJH1.

Streptococcus faecalis JH1 contains two conjugative plasmids, pJH1, an R plasmid that codes for resistance to kanamycin, streptomycin, erythromycin, and tetracycline, and pJH2, a hemolysin-bacteriocin plasmid. Strain JH1 was used as an antibiotic resistance donor in conjugation experiments with two plasmid-free S. faecalis recipient strains, JH2-2 and OG1-RF1.

Broad geographical distribution of a cytotoxin gene mediating beta-hemolysis and bacteriocin activity among Streptococcus faecalis strains.

Conjugative hemolysin-bacteriocin plasmids were isolated from Streptococcus faecalis var. zymogenes strains of diverse geographical origins. Cloned DNA fragments containing the hemolysin-bacteriocin gene(s) from one of these plasmids (pAD1) hybridized to two EcoRI fragments of identical size from each of the five plasmids examined.

Plasmids in the genus Bifidobacterium.

A total of 1461 bacterial isolates, representing 24 different species of the genus Bifidobacterium, were examined for the presence of plasmid DNA. Approximately 20% of the isolates contained detectable plasmids, but only four species were presented: B. longum, the predominant bifid species in the human intestine; B.

Characterization of two tetracycline resistance determinants in Streptococcus faecalis JH1.

Streptococcus faecalis strain JH1 harbors two conjugative plasmids: pJH1, an R plasmid mediating resistance to kanamycin, streptomycin, gentamicin, erythromycin, and tetracycline, and pJH2, a hemolysin-bacteriocin plasmid. Studies of plasmid-cured derivatives of strain JH1 and of transconjugates obtained after mixed incubation of JH1 with the plasmid-free S. faecalis strain JH2-2 revealed the presence of two tetracycline resistance determinants in strain JH1.

Serogrouping of motile Aeromonas species isolated from healthy and moribund fish.

A total of 195 strains of motile Aeromonas isolated from fish were characterized as Aeromonas hydrophila and Aeromonas sobria. In view of the frequency of isolation and the importance of motile Aeromonas species as fish pathogens, a serological classificaton of these organisms was attempted. Antisera were prepared in rabbits against formalinized whole cell suspensions and against boiled cells of 12 different isolates.

Aeromonas hydrophila in rainbow trout: relation between virulence and surface characteristics.

Motile Aeromonas isolated from fish were studied for their virulence in fish in relation to some surface characteristics. The results showed that only the most virulent strains of A. hydrophila used in this study shared a common O antigen, did not agglutinate in acriflavine, settled down after boiling, and were resistant to the bactericidal action of fresh normal mammalian serum.

Effects of tetracycline on the streptococcal flora of periodontal pockets.

The effects of tetracycline on the subgingival streptococcal flora of periodontal patients were examined. Before antibiotic treatment, tetracycline-resistant isolates were obtained from 24 to 25 patients. In most patients, the proportion of the subgingival flora resistant to tetracycline increased after 2 weeks of therapy (1,000 mg of tetracycline/day) and then decreased after the cessation of treatment.

Rapid screening procedure for detection of plasmids in streptococci.

An enrichment procedure, yielding plasmid deoxyribonucleic acid preparations normally containing less than 5% chromosomal contamination, has been devised for the isolation of plasmids from virtually all species of streptococci. The procedure is rapid, reproducible, and inexpensive, requiring no radioisotopes or density gradient centrifugation. The procedure can be used for routine screening of several hundred isolates in a short period of time, and plasmids obtained from 10- to 20-ml cultures can readily be visualized in agarose gels.

Influence of the lactose plasmid on the metabolism of galactose by Streptococcus lactis.

Streptococcus lactis strain DR1251 was capable of growth on lactose and galactose with generation times, at 30 degrees C, of 42 and 52 min, respectively. Phosphoenolpyruvate-dependent phosphotransferase activity for lactose and galactose was induced during growth on either substrate. This activity had an apparent K(m) of 5 x 10(-5) M for lactose and 2 x 10(-2) M for galactose.

"Conjugal" transfer of plasmid DNA among oral streptococci.

The beta plasmid from Streptococcus faecalis strain DS5, which codes for resistance to erythromycin and lincomycin, was introduced into a Lancefield group F streptococcus, strain DR1501, by transformation. This strain, DR1501 (beta), was found to be an excellent donor of the beta plasmid and readily transferred the resistance markers to various lactic acid bacteria, including certain strains of S. mutans, S.

Transformation of group F streptococci by plasmid DNA.

When the Challis strain of Streptococcus sanguis was transformed by the 17 megadalton beta plasmid from Streptococcus faecalis strain DS5, the plasmid underwent a 1.5 megadalton deletion (LeBlanc & Hassell, 1976). Furthermore, the covalently closed circular (CCC) plasmid DNA isolated from Challis transformants was rapidly converted to a linear form which did not possess any detectable transforming activity.