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PubMed2005

Anti-microbial susceptibility of Streptococcus spp. isolated from bovine mastitis in Argentina.

The in vitro susceptibility to penicillin G, erythromycin and clindamycin was determined by the disc diffusion test and by E-test for a total of 47 streptococcal strains (three Streptococcus uberis, 36 Streptococcus agalactiae, eight Streptococcus dysgalactiae spp. dysgalactiae) isolated from bovine intramammary infections in Argentina. Moreover, resistance phenotypes of erythromycin-resistant streptococcal isolates was characterized. MIC90 of penicillin G, erythromycin and clindamycin for S. agalactiae were 0.75, 8.0 and 12.0 microg/ml respectively. Resistance to erythromycin and clindamycin was detected in 13 (27.6%) and 12 (25.5%) isolates respectively. No isolate was resistant to penicillin G. Resistance against macrolides, lincosamides and streptogramin B (MLS(B)) represented by the constitutive MLS(B) phenotype was present in 11 (23.4%) erythromycin-resistant isolates and two isolates (4.3%) expressed the M phenotype. The inducible MLS(B) phenotype was not identified. Results suggest that beta-lactams are the first-line antibiotics when treating streptococcal udder infections; however, the continuous monitoring of the antibiotic resistance is essential, as the emergence of resistant strains has become a growing concern on the therapy of bovine mastitis.

Animals↗
PubMed2006

Antibiotic resistance genes in multidrug-resistant Enterococcus spp. and Streptococcus spp. recovered from the indoor air of a large-scale swine-feeding operation.

AIMS: In this study, multidrug-resistant bacteria previously recovered from the indoor air of a large-scale swine-feeding operation were tested for the presence of five macrolide, lincosamide and streptogramin (MLS) resistance genes and five tetracycline (tet) resistance genes. METHODS AND RESULTS: Enterococcus spp. (n = 16) and Streptococcus spp. (n =16) were analysed using DNA-DNA hybridization, polymerase chain reaction (PCR) and oligoprobing of PCR products. All isolates carried multiple MLS resistance genes, while 50% of the Enterococcus spp. and 44% of the Streptococcus spp. also carried multiple tet resistance genes. All Enterococcus spp. carried erm(A) and erm(B), 69% carried erm(F), 44% carried mef(A), 75% carried tet(M), 69% carried tet(L) and 19% carried tet(K). All Streptococcus spp. carried erm(B), 94% carried erm(F), 75% carried erm(A), 38% carried mef(A), 50% carried tet(M), 81% carried tet(L) and 13% carried tet(K). CONCLUSIONS: Multidrug resistance among airborne bacteria recovered from a swine operation is encoded by multiple MLS and tet resistance genes. These are the first data regarding resistance gene carriage among airborne bacteria from swine-feeding operations. SIGNIFICANCE AND IMPACT OF THE STUDY: The high prevalence of multiple resistance genes reported here suggests that airborne Gram-positive bacteria from swine operations may be important contributors to environmental reservoirs of resistance genes.

Air Microbiology↗
PubMed2006

Inactivation of the group A Streptococcus regulator srv results in chromosome wide reduction of transcript levels, and changes in extracellular levels of Sic and SpeB.

Group A Streptococcus is characterized by the ability to cause a diverse number of human infections including pharyngitis, necrotizing fasciitis, toxic shock syndrome, and acute rheumatic fever, yet the regulation of streptococcal genes involved in disease processes and survival in the host is not completely understood. Genome scale analysis has revealed a complex regulatory network including 13 two-component regulatory systems and more than 100 additional putative regulators, the majority of which remain uncharacterized. Among these is the streptococcal regulator of virulence, Srv, the first Group A Streptococcus member of the Crp/Fnr family of transcriptional regulators. Previous work demonstrated that the loss of srv resulted in a significant decrease in Group A Streptococcus virulence. To begin to define the gene products influenced by Srv, we combined microarray and two-dimensional gel electrophoresis analysis. Loss of srv results in a chromosome wide reduction of gene transcription and changes in the production of the extracellular virulence factors Sic (streptococcal inhibitor of complement) and SpeB (cysteine proteinase). Sic levels are reduced in the srv mutant, whereas the extracellular concentration and activity of SpeB is increased. These data link Srv to the increasingly complex GAS regulatory network.

Antigens, Bacterial↗
PubMed1994

Electrotransformation of Streptococcus agalactiae with plasmid DNA.

A protocol for efficient electrotransformation of Streptococcus agalactiae (group B streptococcus) Lancefield's strain O90R (NTCT 9993) (an unencapsulated derivative of type Ia strain O90) was developed. The Escherichia coli-Streptococcus shuttle vector pDP28 (7.8 kb) carrying the ermB gene for resistance to erythromycin was used as donor DNA. Frozen 'electrocompetent' cells were prepared by repeated washes in 10% glycerol. A 50-microliters aliquot containing about 5 x 10(9) colony forming units of bacteria was subjected to the electric pulse. Optimal conditions for electrotransformation were determined using different media, harvesting cells at different points of the growth curve, and using different field strengths. The dose-response curve for transformation of S. agalactiae with pDP28 showed one-hit kinetics as donor DNA varied between 0.01 and 3 micrograms. The efficiency of electrotransformation for this range of amounts of donor DNA was 1.2 x 10(4) cfu micrograms-1. The transformation frequencies obtained with this electroporation protocol are high enough to allow both subcloning and shotgun cloning of streptococcal DNA in S. agalactiae.

Electroporation↗
PubMed1995

Rapid identification of Streptococcus pneumoniae by PCR amplification of ribosomal DNA spacer region.

Streptococcus pneumoniae is one of the important human pathogens in clinical microbiology. A polymerase chain reaction assay was designed to detect and identify S. pneumoniae through amplification of the ribosomal DNA spacer regions between the pneumococcal 16S-23S ribosomal RNA genes. Thirty-two Streptococcus and non-Streptococcus strains were tested to verify the specificity of the assay, and only S. pneumoniae strains gave a positive reaction. This method is a powerful technique for the rapid identification of S. pneumoniae.

Bacteriological Techniques↗
PubMed1997

Construction and characterization of a recombinant ureolytic Streptococcus mutans and its use to demonstrate the relationship of urease activity to pH modulating capacity.

To begin to understand the contribution of oral microbial ureolysis to the inhibition of dental caries, we sought to construct a recombinant, ureolytic mutans streptococcus and correlate the ureolytic capacity of plaque bacteria with pH moderating ability. Streptococcus mutans GS-5 was transformed with a plasmid containing the urease genes from Streptococcus salivarius 57.I. The recombinant strain, S. mutans AC04, stably maintained the urease genes. High levels of urease activity were detected, with a maximum specific activity of 0.9 mumol of urea hydrolyzed/min/mg cell dry weight when the growth medium was supplemented with 50 microM exogenous NiCl2. Harboring the recombinant plasmid, or growth in NiCl2, did not markedly affect the glycolytic capacity of S. mutans. In vitro pH drop analysis of S. mutans AC04, metabolizing glucose and physiologically relevant concentrations of urea simultaneously, demonstrated that increasing the urease activity of plaque bacteria resulted in a corresponding reduction in the depth and the duration of the glycolytic pH fall. The results demonstrate the feasibility of engineering urease producing S. mutans and suggest that enhancing the ureolytic capacity of dental plaque, particularly cariogenic plaque, may help to offset the progression of the caries process.

Hydrogen-Ion Concentration↗
PubMed1998

Small cryptic plasmids of Streptococcus pneumoniae belong to the pC194/pUB110 family of rolling circle plasmids.

The DNA sequences of two related plasmids pPR1 and pPR3 described previously in Streptococcus pneumoniae isolates from Germany and Spain were now determined. Both plasmids belong to a family of rolling circle (RC) plasmids found in a variety of bacteria. Their GC content with 32% is lower than that of the S. pneumoniae chromosomal DNA. The plasmid pPR3 has a molecular size of 3160 bp with four putative open reading frames, whereas pPR1 contained a deletion of 313 bp that included the 5'-part of ORF2 and upstream regions and differed by three bp from pPR3. The predicted protein of ORF1 showed high similarity to replication proteins of RC plasmids with 74% identical amino acids to RepA of Streptococcus thermophilus plasmids. Sequences similar to the plus origin of replication of ssDNA plasmids were present in both plasmids. They also contained a 152-bp region with over 83% identity to the minus origin of replication of the Streptococcus agalacticae plasmid pMV158.

Base Sequence↗
PubMed2000

The extracellular hyaluronidase gene (hylA) of Streptococcus pyogenes.

Group A streptococci produce an extracellular hyaluronidase (hyaluronate lyase) which may be associated with the spread of the organism during infection. The gene for this hyaluronidase (hylA) encodes an 868 amino acid protein with a molecular size of 99636 Da. Cleavage of the proposed signal peptide results in an extracellular protein of 95941 Da. Comparison with other bacterial hyaluronidases indicates strong similarities to the genes from Streptococcus pneumoniae, Streptococcus agalactiae and Staphylococcus aureus. A region internal to the hylA gene was amplified from all 175 strains of Streptococcus pyogenes tested suggesting a widespread distribution of the gene.

DNA, Bacterial↗
PubMed1995

[A case of toxic shock-like syndrome due to Streptococcus pyogenes].

A case of toxic-shock syndrome due to Streptococcus pyogenes is reported. A 76-year-old female was admitted with complaints of fevers and chills. She had been suffering from cellulitis on her right dorsum pedis for 7 months. Laboratory data on admission showed elevated values of WBC, CRP, and dysfunction of the liver and kidney. She was diagnosed as sepsis due to the cellulitis, and was treated with PIPC and FMOX. However, several hours after admission, her blood pressure decreased and oliguria appeared. Bacteriological examinations from the blood and the cellulitis revealed group A beta-hemolytic Streptococcus which gave streptococcal pyrogenic exotoxin (T-28, SPE.B + C). She died 23 hours after her admission in spite of changing antibiotics to a high-dose of PC-G therapy. This is one of the rare cases of toxic shock-like syndrome due to Streptococcus pyogenes from the cellulitis of the dorsum pedis.

Aged↗
PubMed1996

[A case of fluminant septic shock due to Streptococcus agalactiae in a patient with MPO-ANCA related glomerulonephritis].

Recently group A Streptococcus toxic shock like syndrome (TSLS) has been reported, but as for group B streptococcus (S. agalactiae) infection, there have been little documentation in the literature. We report a case of fluminant septic shock due to Streptococcus agalactiae (S. agalactiae). A 72-year-old male was admitted to our hospital because of general fatigue and azotemia. He was diagnosed as having MPO-ANCA related glomerulonephritis and treated with steroid therapy. Gradually he was doing well. On the 228th hospital day, he suddenly had tachypnea, transient conscious disturbance, and profound hypotension. About 16 hours later, he died despite intensive treatment. S. agalactiae was isolated from the blood. Autopsy revealed bilateral bronchopneumonia and shock liver. To our knowledge, this is the first report of septic shock caused by S. agalactiae.

Aged↗
PubMed1997

[Anti-bacterial activities of a sulfonated human immunoglobulin preparation against penicillin resistant Streptococcus pneumoniae and Pseudomonas aeruginosa].

Anti-bacterial activities of a sulfonated human immunoglobulin preparation against penicillin resistant Streptococcus pneumoniae and Pseudomonas aeruginosa were examined. Five week old CBA/J mice were challenged by 10 times of 50% lethal doses of penicillin sensitive (SP1) and resistant (SP2) strains of Streptococcus pneumniae serotype 19, and were treated with a sulfonated human immunoglobulin preparation (hIg). Fifty % protective dose (ED50) were 2-4 mg hIg/ mouse. These doses were parallel with the challenged doses despite of the challenged bacteria, and it was calculated that 6 x 10(6) bacteria were killed by one mg of hIg in both bacteria. Minimal inhibitory concentrations (MIC) of piperacillin, flomoxef, imipenem, amikacin and ofloxacin against SP1 and SP2 were estimated under the presence of various concentrations of hIg. It was found that under the presence of over 10-20 mg/ml of hIg, SP1 and SP2 were not grown even without any antibiotic. That is, MIC of hIg itself against penicillin sensitive and resistant Streptococcus pneumoniae serotype 19 were 10-20 mg/ml. Since about 10(6) bacteria/ml were used for this test, it was calculated that 5-10 x 10(4) bacteria were killed by one mg of hIg in vitro. This result suggested that in vivo anti-bacterial activities of hIg could be 100 times higher than that in vitro. Synergistic or at least additive effects between hIg and all antibiotics tested were seen by the MIC. If hIg was 100 times effective in in vivo, these results suggested that hIg could improve the effect of chemotherapy in clinical cases. Similar in vitro test were carried out for Pseudomonas aeruginosa, and synergistic or at least additive effects between hIg and all antibiotics tested were also confirmed in Pseudomonas aeruginosa. This result suggested that hIg could be effective for clinical pseudomonas infection.

Animals↗
PubMed2002

[A case of bacteremic group A streptococcus infection with organ dysfunction following a minor skin abrasion].

A 20-year-old male was admitted to our hospital with the chief complaints of high fever and pain around his right hip joint. He had his right knee injured with a slight abrasion three weeks before. The diagnosis of suppurative lymphadenitis of inguen was made, and intravenous cefotiam was started. Despite these treatments his fever continued, general edema and dry cough appeared. Arterial blood gas showed severe hypoxia and chest X ray revealed marked cardiomegaly associated with ground-glass opacity over bilateral lower pulmonary fields. Slight renal insufficiency was also observed. On the fifth hospital day, the culture specimens of both blood and pus from the abrasion on admission yielded Streptococcus pyogenes. His condition was diagnosed as severe group A Streptococcus infection, then antibiotics were switched to intravenous administration of high dose aminobenzyl penicillin and clindamycin in combination with protease inhibitor, urinastatin. After these treatments, his condition improved and he was discharged from the hospital after one month. Group A Streptococcus may cause uncommon but life-threatening infection such as septicemia. Early recognition of the disease and prompt initiation of appropriate treatment may lead to successful outcome.

Adult↗
PubMed2003

[Purulent meningitis caused by Streptococcus suis in a pig breeder].

A case of Purulent meningitis caused by Streptococcus suis type 2 is reported here. It occurred in a 58-year-old male pig breeder. A few days before presentation, the patient had experienced headache, systemic articular pain and fever (38.8 degrees C). On admission, he was stuporous and had neck stiffness and hemiparesis. Examination of cerebrospinal fluid showed purulent meningitis. The cultures identified Streptococcus suis II by PCR and specific serum. 2 months later, the patient was discharged in good clinical condition except for hearing loss. Streptococcus suis is known to be an important pathogen in the swine industry, this report is the first case of S. suis meningitis in man, in Japan.

Animal Husbandry↗
PubMed1981

Genetic study of plasmid-associated zonal resistance to lincomycin in Streptococcus pyogenes.

The phenomenon of zonal resistance to lincomycin, which is characteristic of most clinical isolates with lincomycin resistance in Streptococcus pyogenes, has been studied. These strains grow within a defined concentration range of lincomycin (approximately 60 to 200 microgram/ml), or at lincomycin concentrations below the minimal inhibitory concentration for susceptible strains. It is shown that the zonal growth phenomenon is a stable phenotype and results from induction of resistance only within the zonal concentration range of lincomycin. These strains also possess inducible resistance to erythromycin which is nonzonal in character. One-step mutations to constitutive resistance have been isolated which are of two types: constitutive for lincomycin or for erythromycin, but not for both. Those strains with constitutive erythromycin resistance retain their zonal resistance for lincomycin. Mutants doubly constitutive for both lincomycin and erythromycin can be obtained by a second mutational step from either of the singly constitutive mutants. Satellite deoxyribonucleic acid has been shown to be present in the zonal resistant strains. A plasmid, pSM10419, of 14.9 megadaltons, has been isolated from one of the doubly constitutive mutants and used to jointly transform Streptococcus sanguis strain Challis to constitutive resistance to both lincomycin and erythromycin. From this, a multicopy plasmid of reduced size, pSM10 (5.4 megadaltons), which retains its resistance phenotype, has been isolated and mapped with restriction endonucleases HindIII (three sites), EcoRI (one site), KpnI (one site), and HpaI (one site). The staphylococcal plasmid pC221 (2.9 megadaltons; chloramphenicol resistant) has been fused to pSM10 at the EcoRI site resulting in a chimeric plasmid, pSM10221 (8.3 megadaltons), which retains resistance to chloramphenicol, erythromycin, and lincomycin. pSM10 is therefore suggestive as an effective cloning vehicle for the genus Streptococcus.

DNA, Bacterial↗
PubMed1988

Occurrence of the Campylobacter resistance gene tetO in Enterococcus and Streptococcus spp.

The distribution of nucleotide sequences related to tetK, tetL, tetM, and tetO was studied by dot blot hybridization in 178 strains of Streptococcus and Enterococcus spp. that were resistant to tetracycline. The tetO gene, which is responsible for tetracycline resistance in Campylobacter spp., was detected in six Streptococcus strains and two Enterococcus strains, in which it was borne by similar plasmids. This observation confirms our previous proposal that tetO originated in gram-positive cocci. tetM, the most prevalent resistance gene, was present alone in 109 strains and associated with tetL in 33 strains in which the two genes contributed cooperatively to high-level tetracycline resistance. tetL was present alone in five Enterococcus strains, and tetK was detected in a single Streptococcus strain. The existence of 22 strains that did not hybridize to the probes suggest that tetracycline resistance in streptococci and enterococci involves additional gene classes as well.

Campylobacter↗
PubMed1990

High-level chromosomal gentamicin resistance in Streptococcus agalactiae (group B).

This is the first report of high-level gentamicin resistance in a group B streptococcus. Strain B128 of serotype II was isolated from an infected leg wound in 1987. B128 was resistant to high levels of gentamicin as well as of all other available aminoglycosides and was also resistant to tetracyclines. No bactericidal synergism was found between ampicillin or vancomycin and any of these aminoglycosides. Gentamicin, kanamycin, streptomycin, and tetracycline resistance determinants transferred by conjugation into a plasmid-free group B streptococcus recipient at a frequency of 10(-8) to 10(-9) transconjugants per donor cell. No transconjugants were detected when streptococci of groups A, C, and G, Streptococcus sanguis, or Enterococcus faecalis was used as a recipient. No plasmids were detected in B128 or in any of the four transconjugants tested. By DNA-DNA hybridization, homology was detected between gene aac6/aph2, of E. faecalis origin, and a 2.4-kilobase HindIII chromosomal fragment of B128; homology to the genes aph3 and aadE, of E. faecalis origin, was found with HindIII chromosomal fragments of the same size (3.0 kilobases). Strains like B128, which potentially can be responsible for severe neonatal infections, are of great clinical concern, since there are to date no antibiotic combinations exhibiting bactericidal synergism against them.

Blotting, Southern↗
PubMed1997

Cloning and characterization of a novel macrolide efflux gene, mreA, from Streptococcus agalactiae.

A strain of Streptococcus agalactiae displayed resistance to 14-, 15-, and 16-membered macrolides. In PCR assays, total genomic DNA from this strain contained neither erm nor mef genes. EcoRI-digested genomic DNA from this strain was cloned into lambda Zap II to construct a library of S. agalactiae genomic DNA. A clone, pAES63, expressing resistance to erythromycin, azithromycin, and spiramycin in Escherichia coli was recovered. Deletion derivatives of pAES63 which defined a functional region on this clone that encoded resistance to 14- and 15-membered, but not 16-membered, macrolides were produced. Studies that determined the levels of incorporation of radiolabelled erythromycin into E. coli were consistent with the presence of a macrolide efflux determinant. This putative efflux determinant was distinct from the recently described Mef pump in Streptococcus pyogenes and Streptococcus pneumoniae and from the multicomponent MsrA pump in Staphylococcus aureus and coagulase-negative staphylococci. Its gene has been designated mreA (for macrolide resistance efflux).

Amino Acid Sequence↗
PubMed1997

Efficacy of azithromycin or clarithromycin for prophylaxis of viridans group streptococcus experimental endocarditis.

The efficacy of azithromycin or clarithromycin was compared to that of amoxicillin, clindamycin, or erythromycin for the prevention of viridans group streptococcus experimental endocarditis. Rabbits with catheter-induced aortic valve vegetations were given no antibiotics or two doses of amoxicillin at 25 mg/kg of body weight, azithromycin at 10 mg/kg, clarithromycin at 10 mg/kg, clindamycin at 40 mg/kg followed by clindamycin at 20 mg/kg, or erythromycin at 10 mg/kg. Antibiotics were administered 0.5 h before and 5.5 h after intravenous infusion of 5 x 10(5) CFU of Streptococcus milleri. Forty-eight hours after bacterial inoculation, the rabbits were killed and aortic valve vegetations were aseptically removed and cultured for bacteria. Infective endocarditis occurred in 88% of untreated animals, 1% of animals receiving amoxicillin, 9% of animals receiving erythromycin, 0% of animals receiving clindamycin, 2.5% of animals receiving clarithromycin, and 1% of animals receiving azithromycin. All five regimens were more effective (P < 0.001) than no prophylaxis. Erythromycin was less effective (P < 0.05) than amoxicillin or clindamycin. Azithromycin or clarithromycin was as effective as amoxicillin, clindamycin, or erythromycin for the prevention of viridans group streptococcus experimental endocarditis in this model.

Amoxicillin↗