virginiamycin and Streptococcal-Infections

The advent of vancomycin-resistant enterococci in the 1990s and the threat posed by vancomycin resistance in Staphylococcus aureus led to the development of several new antimicrobial agents active against these pathogens. Quinupristin/dalfopristin was the first such drug to be commercially available but adverse effects have meant that the drug is now rarely used. Linezolid, the first antimicrobial of the oxazolidinone class, has met with more widespread use and has both an intravenous and an oral formulation. Daptomycin is a lipopeptide antimicrobial that is rapidly bactericidal against S. aureus. It is effective in the therapy of S. aureus bloodstream infections but is inactivated by pulmonary surfactant, making it of no use in the therapy of pneumonia. Tigecycline, by contrast, is bacteriostatic against most pathogens but has a broad spectrum of antimicrobial activity and has enhanced penetration into many tissues. Other new antibiotics (dalbavancin, telavancin, ceftobiprole and doripenem) are currently under clinical development and hold promise for widespread clinical use in the next decade.

Topics: Acetamides; Anti-Bacterial Agents; Bacterial Infections; Daptomycin; Humans; Linezolid; Minocycline; Oxazolidinones; Staphylococcal Infections; Streptococcal Infections; Tigecycline; Virginiamycin

Bacterial meningitis caused by Streptococcus pneumoniae is an important cause of neurological morbidity and mortality in both children and adults. With increasing antibiotic resistance in pneumococci and documented microbiological failure in treatment of pneumococcal meningitis with cefotaxime and ceftriaxone, the need for alternative antibiotic therapy is critical. Of the currently available options, vancomycin has shown the most promise, particularly when used in combination with ceftriaxone or cefotaxime. Rifampin, also used in combination with either ceftriaxone or cefotaxime, has demonstrated encouraging preliminary results against antibiotic-resistant pneumococci as well. Chloramphenicol has unexpectedly yielded discouraging clinical results in children with infection caused by penicillin-resistant strains. Of the investigational antibiotics currently in clinical trials for the treatment of meningitis, meropenem, a carbapenem-class antibiotic, has demonstrated increased activity against penicillin-resistant pneumococci compared with that of other beta-lactam antibiotics, while having a safety profile similar to that of the cephalosporins.

Topics: Adult; Anti-Bacterial Agents; Anti-Infective Agents; Child; Child, Preschool; Chloramphenicol; Clindamycin; Female; Fluoroquinolones; Humans; Infant; Infant, Newborn; Lactams; Male; Meningitis, Bacterial; Naphthyridines; Penicillin Resistance; Rifampin; Streptococcal Infections; Streptococcus pneumoniae; Vancomycin; Virginiamycin

This study was aimed to compare the clinical and antibacterial efficacy of fusidic acid 500 mg twice a day, per os, over 7.5 days) to pristinamycin 1 g twice a day, per os, over 10 days).. Patients aged over 18, suffering from a superficial pyoderma requiring antibiotherapy and having given their informed consent were enrolled in a controlled, multicentre, double blind double dummy, parallel groups study. From day 0 to day 10, the patients received the randomised treatment. Those who were cured at day 11 had a visit at day 25 without any treatment between day 11 and day 25. A swab was performed on days 0, 11 and 25. The two treatment groups were compared in terms of efficacy, safety and global cost.. 334 patients seen in dermatologic consultation were included in the study. 313 patients were analysed on an intent-to-treat basis. 158 received fusidic acid (FA) and 155 were treated with pristinamycin (P). At D11, 126 patients were cured in the FA group (79.7%) and 118 in the P group (76.1%) (p = 0.44). The bacteriological success rate was 85.2% in the FA group and 82.7 in the P group (p = 0.67). The recovery was confirmed in 92.6% of the FA patients and 90.4% of the P patients at D25 (p = 0.56). Digestive tolerance was better with fusidic acid than with pristinamycin. In economic terms, fusidic acid was cheaper than pristinamycin: 443 French francs in the FA group versus 545 FF in the P group.. Therefore we conclude that an oral course of 7.5 days with fusidic acid is an efficient and cheaper alternative to a treatment with pristinamycin over 10 days.

Topics: Administration, Oral; Adult; Anti-Bacterial Agents; Costs and Cost Analysis; Data Interpretation, Statistical; Double-Blind Method; Female; Fusidic Acid; Humans; Male; Middle Aged; Placebos; Pyoderma; Skin Diseases, Bacterial; Staphylococcal Skin Infections; Streptococcal Infections; Time Factors; Virginiamycin

We recently demonstrated that oral roxithromycin is as effective as intravenous penicillin G in adults with erysipelas. We therefore evaluated the effectiveness of pristinamycin, an antibiotic which is very active on streptococci and Staphylococcus aureus, in non-necrotizing bacterial dermohypodermitis in adults.. This prospective open study was conducted in one center and included immunocompetent patients with bacterial dermophypodermitis without signs of toxicity or local manifestations suggesting necrotizing fasciitis. Bacteriology tests included direct immunofluorescence for streptococcus (groups A, C, G) on skin biopsies of the lesion before treatment. Patients were treated with pristinamycin (Pyostacine 500, 3 g/day until 10 days after apyrexia), and evaluated clinically on day 0, 2, 6, 8, and 15. Overall treatment effect was assessed on day 15.. The study group included 42 adults (23 woman and 19 men; mean age 64 +/- 3.5 yr). In 39 cases (93%), the bacterial dermohypodermitis was localized on the lower limb. The inflammatory lesion was well delimited, a characteristic feature of erysipelas, in 32 cases (76%). Sample culture, direct immunofluorescence or serology findings demonstrated presence of streptococci in 33 cases (79%). A single treatment with pristinamycin was successful in 36 patients, giving an overall rate of 86%. Drainage of a localized abscess was successful in 5 of 6 patients after initial failure of antibiotic treatment.. This prospective study demonstrated the effectiveness of pristinamycin in non-necrotizing bacterial dermohypodermitis in the adult, especially in erysipelas. Overall effectiveness was comparable with that reported for penicillin G or macrolides in erysipelas.

Topics: Adult; Aged; Aged, 80 and over; Anti-Bacterial Agents; Erysipelas; Female; Humans; Male; Middle Aged; Prospective Studies; Skin Diseases, Bacterial; Staphylococcal Infections; Streptococcal Infections; Treatment Outcome; Virginiamycin

Seven Streptococcus agalactiae isolates were obtained from the vagina of 80 asymptomatic women. Three of these isolates showed multi-drug resistant (MDR) phenotypes: two isolates were resistant to clarithromycin, clindamycin, erythromycin, and tetracycline; and one isolate was resistant to clarithromycin, clindamycin, erythromycin, tetracycline, and quinupristin/dalfopristin. There was no clonal relationship among the MDR isolates. This is the first report of quinupristin/dalfopristin-resistant S. agalactiae.

Topics: Adult; Anti-Bacterial Agents; DNA, Bacterial; DNA, Ribosomal; Drug Resistance, Multiple, Bacterial; Female; Humans; Korea; Microbial Sensitivity Tests; Middle Aged; Molecular Sequence Data; RNA, Ribosomal, 16S; Streptococcal Infections; Streptococcus agalactiae; Vaginal Smears; Virginiamycin

A retrospective observational study in Taiwan, 1998-2004, identified 92 patients with group G streptococcal bacteremia; 86 had Streptococcus dysgalactiae subspecies equisimilis. The most common diagnosis was cellulitis (48 cases), followed by primary bacteremia (34 cases). Infection recurred in 9 patients. Mortality rate was low (3.3%); resistance to quinupristin-dalfopristin was high.

Topics: Adolescent; Adult; Aged; Anti-Bacterial Agents; Bacteremia; Cellulitis; Child; Drug Resistance, Bacterial; Female; Humans; Male; Microbial Sensitivity Tests; Middle Aged; Streptococcal Infections; Streptococcus; Taiwan; Virginiamycin

This study evaluated the current status of antimicrobial resistance in clinical isolates of Streptococcus pyogenes in Taiwan as part of the SMART (Surveillance from Multicenter Antimicrobial Resistance in Taiwan) program. In 2001, 419 different isolates of S. pyogenes, including 275 from respiratory secretions, 87 from wound pus, and 31 from blood, were collected from nine hospitals in different parts of Taiwan. MICs of 23 antimicrobial agents were determined at a central location by the agar dilution method. All of the isolates were susceptible to penicillin (MIC at which 90% of the isolates were inhibited [MIC(90)], moxifloxacin > ciprofloxacin = levofloxacin = gatifloxacin > gemifloxacin) demonstrated potent activity against nearly all of the isolates of S. pyogenes tested. Thirty-two isolates (8%) were not susceptible to quinupristin-dalfopristin. Seventeen percent of isolates had telithromycin MICs of >or=1 microg/ml, and all of these isolates exhibited erythromycin MICs of >or=32 microg/ml. The high prevalence of resistance to telithromycin (which is not available in Taiwan) limits its potential use in the treatment of S. pyogenes infections, particularly in areas with high rates of macrolide resistance.

Topics: Anti-Bacterial Agents; Drug Resistance, Bacterial; Erythromycin; Genes, Bacterial; Humans; Ketolides; Macrolides; Microbial Sensitivity Tests; Phenotype; Streptococcal Infections; Streptococcus pyogenes; Taiwan; Virginiamycin

For many years group A streptococci of T type 28 (T28) have been common in southern Sweden; however, since 1995 resistance to both macrolide-lincosamide-streptogramin B (MLS) antibiotics and tetracycline was observed among T28 isolates, which prompted the present studies on clonal relatedness of antibiotic-resistant T28 strains. By extended T typing, 95 of 100 examined tetracycline-resistant strains showed the combination T9-T13-T28; of these, 94 belonged to M type 77 (M77) and one belonged to M73. Three strains were T28-M28 and two were T28-M nontypeable. The serological M77 was confirmed by PCR capture enzyme-linked immunosorbent assay, emm amplicon restriction profiling, and emm sequence typing. Fifty strains were examined for superantigen genes: speA was detected in three blood isolates only, whereas all isolates harbored speB, and only two of the strains were negative for speC. Eighty-nine of the 100 strains were also macrolide resistant, of which 59 were inducibly MLS resistant (IR) and 21 were constitutively MLS resistant (CR), 6 were noninducibly resistant (NI), and 3 had novel subphenotypes recently reported by our group. Resistance genes were determined by PCR and hybridization methods. Eighty-four of the 100 strains harbored tetM. ermB was detected in all CR and IR strains, and mefA was found in all NI strains; both ermB and mefA were identified in two strains with novel subphenotypes. Pulsed-field gel electrophoresis showed that these antibiotic-resistant M77 strains belonged to at least five different clones.

Topics: Anti-Bacterial Agents; Antigens, Bacterial; Bacterial Outer Membrane Proteins; Bacterial Proteins; Carrier Proteins; Drug Resistance, Microbial; Electrophoresis, Gel, Pulsed-Field; Enzyme-Linked Immunosorbent Assay; Exotoxins; Humans; Lincosamides; Macrolides; Membrane Proteins; Microbial Sensitivity Tests; Polymerase Chain Reaction; Serotyping; Streptococcal Infections; Streptococcus pyogenes; Sweden; Tetracycline Resistance; Virginiamycin

Eighty percent (21 of 26) of macrolide-resistant Peptostreptococcus strains studied harbored the ermTR gene. This methyltransferase gene is also the most frequently found gene among macrolide-lincosamide-streptogramin B-resistant Streptococcus pyogenes strains. Transfer of the ermTR gene from Peptostreptococcus magnus to macrolide-susceptible S. pyogenes strains indicates that this resistance determinant may circulate among gram-positive aerobic and anaerobic species of the oropharyngeal bacterial flora.

Topics: Anti-Bacterial Agents; Bacterial Proteins; Conjugation, Genetic; Drug Resistance, Microbial; Electrophoresis, Agar Gel; Genes, Bacterial; Humans; Lincosamides; Macrolides; Methyltransferases; Peptostreptococcus; Reverse Transcriptase Polymerase Chain Reaction; Streptococcal Infections; Streptococcus pyogenes; Virginiamycin

In a prospective multicenter study (1996 to 1999), 156 episodes of bacteremic streptococcal infections of neutropenic patients were evaluated. Streptococcus oralis (26.3%), S. pneumoniae (26.3%), S. agalactiae (11.5%), S. mitis (9%), and S. pyogenes (5.8%) were the predominant species. Four strains (2.6%) were found to be intermediately resistant to penicillin. One strain (0.6%) was found to be highly resistant to penicillin (MIC, 8 mg/liter). Reduced susceptibility to penicillin was detected among S. oralis (14.6%), S. mitis (7.1%), and S. pneumoniae (4.9%) isolates but was not recorded among S. agalactiae and S. pyogenes. Resistance rates and intermediate resistance rates for other antimicrobials were as follows (all species): amoxicillin, 1.3 and 3.2%; erythromycin, 16 and 2.6%; clindamycin, 5.8 and 0%; ciprofloxacin, 1.9 and 7.7%. Quinupristin-dalfopristin showed good in vitro activity against most streptococcal isolates (MIC at which 50% of the isolates were inhibited [MIC(50)], 0.5 mg/liter; MIC(90), 1 mg/liter, MIC range, 0.25 to 4 mg/liter).

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Anti-Bacterial Agents; Bacteremia; Blood; Child; Child, Preschool; Drug Resistance, Microbial; Female; Humans; Infant; Male; Microbial Sensitivity Tests; Middle Aged; Neutropenia; Prospective Studies; Streptococcal Infections; Streptococcus; Virginiamycin

Macrolide-resistance was assessed in 216 consecutive Streptococcus pyogenes isolates from throat infections in the region of Aachen, Germany. Seventeen isolates were resistant to erythromycin: 12 isolates revealed a macrolide (M) phenotype and harbored mefA, and five strains expressed an inducible macrolide-lincosamide-streptogramin B (MLSB) phenotype of which four strains harbored ermA(TR) and one strain contained ermB(AM). Telithromycin (HMR 3647) and quinupristin/dalfopristin remained active particularly against the ermA(TR)-containing S. pyogenes isolates studied. Random amplified polymorphic DNA analysis identified multiple clones among erythromycin-resistant strains, but did not discriminate beyond the emm-type. mefA was present in three isolates either with emm2, emm12, or emm75, and in nine isolates with emm4. All four strains with ermA(TR) contained emm77, and the single strain with ermB(AM) harbored emm1. Despite the relative low rate of macrolide-resistance, these data suggest that at least three different macrolide-resistance determinants are prevalent in Germany and that mefA has spread rapidly into multiple clones of S. pyogenes.

Topics: Anti-Bacterial Agents; Drug Resistance; Erythromycin; Genotype; Germany; Ketolides; Macrolides; Microbial Sensitivity Tests; Pharynx; Phenotype; Polymorphism, Restriction Fragment Length; Regulon; Respiratory Tract Infections; Reverse Transcriptase Polymerase Chain Reaction; Streptococcal Infections; Streptococcus pyogenes; Streptogramins; Virginiamycin

The emergence and sustained prevalence of Gram-positive organisms resistant to antimicrobials has been of interest for over a decade. Quinupristin/dalfopristin (formerly RP 59500 or Synercid) is a new injectable streptogramin combination that has been reported to have activity against Gram-positive organisms, even those with documented MLS(B) resistance. However, the two case reports presented here illustrate three well-documented Streptococcus spp. strains (S. mitis, S. pneumoniae) to be resistant to quinupristin/dalfopristin (MICs at 3, 8, and 12 microg/ml) following referral as routine isolates in the SENTRY Antimicrobial Surveillance Program. The S. pneumoniae pleural fluid isolate was cross-resistant to erythromycin. Both bacteremic S. mitis strains were resistant to macrolides (erythromycin, azithromycin, clarithromycin), lincosamides (clindamycin), and fluoroquinolones. Patient histories indicated no prior use of MLS class antimicrobials for the S. mitis case, but the patient having the S. pneumoniae isolate did receive prior treatment of erythromycin and clindamycin. All isolates had modestly increased penicillin MICs of 0.12 microg/ml. The mode of resistance to quinupristin/dalfopristin was not evident (sat A-negative by PCR); and these cases illustrate the existence of streptogramin-resistant isolates before the introduction of this antimicrobial class into human clinical practice.

Topics: Adult; Aged; Aged, 80 and over; Anti-Bacterial Agents; Drug Resistance, Microbial; Female; Humans; Male; Streptococcal Infections; Streptococcus; Virginiamycin

Topics: Anti-Bacterial Agents; Clinical Trials as Topic; Enterococcus faecium; Gram-Positive Bacterial Infections; Humans; Oxazoles; Oxazolidinones; Streptococcal Infections; Streptococcus pyogenes; Vancomycin Resistance; Virginiamycin

A total of 68 viridans group streptococci, including 31 Streptococcus sanguis, 12 S. mitis, 3 S. salivarius, and 8 S. milleri from blood, and an additional 14 S. milleri from abscesses and normally sterile sites, were tested against penicillin, amoxicillin, cefazolin, ceftriaxone, meropenem, clindamycin, quinupristin/dalfopristin, rifampin, levofloxacin, ofloxacin, vancomycin, and gentamicin with the microdilution method. The susceptibility rates for S. sanguis were: penicillin, 74%; amoxicillin, 84%; ceftriaxone, 94%; clindamycin, 87%, and vancomycin, 100%. The susceptibility rates for S. mitis were: penicillin, 42%; amoxicillin, 67%; ceftriaxone, 58%; clindamycin, 100%; and vancomycin, 100%. The susceptibility rates for S. milleri were: penicillin, 100%, amoxicillin. 100%; ceftriaxone, 100%, clindamycin, 100%; and vancomycin, 100%. Two of the three isolates of S. salivarius were susceptible to penicillin, amoxicillin, and ceftriaxone; all were susceptible to clindamycin and vancomycin. Levofloxacin, quinupristin/dalfopristin, and rifampin were highly active against all isolates.

Topics: Amoxicillin; Anti-Bacterial Agents; Cefazolin; Ceftriaxone; Clindamycin; Drug Resistance, Microbial; Gentamicins; Humans; Levofloxacin; Meropenem; Microbial Sensitivity Tests; Ofloxacin; Penicillins; Rifampin; Streptococcal Infections; Streptococcus; Thienamycins; Vancomycin; Virginiamycin

From January 1988 to December 1994, 66 consecutive blood culture isolates of viridans group streptococci collected from febrile neutropenic cancer patients were tested for antimicrobial susceptibilities by the agar dilution method. The antibiotics studied were erythromycin, clarithromycin, roxithromycin, dirithromycin, azithromycin, josamycin, diacetyl-midecamycin, spiramycin, and quinupristin-dalfopristin. A total of 26 (39.4%) strains were resistant to erythromycin with an MIC range of 0.5 to > 128 micrograms/ml. The strains were classified into three groups according to their penicillin susceptibility: 42 (63.6%) were susceptible, 8 (12.1%) were intermediately resistant, and 16 (24.3%) were highly resistant. The percentages of erythromycin-resistant strains in each group were 23.8, 62.5, and 68.8%, respectively. Streptococcus mitis was the species most frequently isolated (83.3%) and showed the highest rates of penicillin (40%) and erythromycin (43.6%) resistance. MICs of all macrolide antibiotics tested and of quinupristin-dalfopristin were higher for penicillin-resistant strains than for penicillin-susceptible strains. All macrolide antibiotics tested had cross-resistance to erythromycin, which was not observed with quinupristin-dalfopristin. Our study shows a high rate of macrolide resistance among viridans group streptococci isolated from blood samples of neutropenic cancer patients, especially those infected with penicillin-resistant strains. These findings make macrolides unsuitable prophylactic agents against viridans group streptococcal bacteremia in this patient population.

Topics: Anti-Bacterial Agents; Drug Resistance, Microbial; Erythromycin; Humans; Microbial Sensitivity Tests; Neoplasms; Neutropenia; Penicillin Resistance; Streptococcal Infections; Streptococcus; Virginiamycin

RP 59500 is a new injectable streptogramin composed of two synergistic components (quinupristin and dalfopristin) which are active against a number of erythromycin-susceptible and -resistant gram-positive bacteria. The following experiments investigate the ability of RP 59500 to prevent experimental endocarditis due to either of two erythromycin-susceptible streptococcal isolates or their constitutively erythromycin-resistant Tn916 delta E transconjugants. RP 59500 had low MICs (0.125 to 0.5 mg/liter) for all four test organisms and was substantially bactericidal in vitro. Rats with catheter-induced aortic vegetations were given single-dose antibiotic prophylaxis 30 to 60 min before bacterial inoculation through a computerized pump system which permitted the simulation of drug kinetics for humans produced by either 7 mg of RP 59500 per kg of body weight or 1 g of vancomycin. Single-dose RP 59500 prophylaxis successfully prevented endocarditis due to both the erythromycin-susceptible parent strains and their erythromycin-resistant derivatives in rats challenged with the minimal inoculum infecting 90% of controls. In addition, RP 59500 also prevented infection in animals challenged with fivefold-larger inocula of the erythromycin-susceptible parent strains. Vancomycin successfully prevented endocarditis due to any of the four test organisms. These results underline the in vivo efficacy of RP 59500 against both erythromycin-susceptible and -resistant streptococci. Such good results against the resistant strains would not be expected with erythromycin or clindamycin, which are the standard macrolidelincosamide-streptogramin antibiotics used for endocarditis prophylaxis in humans. An oral form of RP 59500 which might advantageously replace some of the older prophylactic regimens is currently being developed.

Topics: Animals; Conjugation, Genetic; Drug Resistance, Microbial; Endocarditis, Bacterial; Erythromycin; Female; Microbial Sensitivity Tests; Rats; Rats, Wistar; Streptococcal Infections; Streptococcus; Vancomycin; Virginiamycin

High throughput chemical file screening with an enzymatic assay to detect inhibitors of the ErmC methyltransferase enzyme from macrolide-lincosamide-streptogramin B (MLSB) resistant pathogenic bacteria identified low molecular weight compounds that had IC50S (50% inhibitory concentration) in the nMolar to microMolar range. These same inhibitors were assessed in vitro for their capacity to inhibit the liver enzyme, cathechol-O-methyltransferase and the prokaryotic enzyme, EcoRI methylase. Selective inhibitors of the ErmC methyltransferase were tested in tertiary assays to determine their minimal inhibitory concentrations (MICs), as single agents and in combination with the macrolide, azithromycin, against strains of pathogenic bacteria expressing MLSB-resistance. Compounds that were active in vitro, alone or in combination with azithromycin, against strains of macrolide-resistant pathogens were tested in a mouse model of infection using an MLSB-resistant strain of Staphylococcus aureus or a macrolide-susceptible strain of Streptococcus pyogenes.

Topics: Animals; Anti-Bacterial Agents; Azithromycin; Drug Resistance, Microbial; Drug Therapy, Combination; Enzyme Inhibitors; Lincosamides; Macrolides; Methyltransferases; Mice; Staphylococcal Infections; Staphylococcus aureus; Streptococcal Infections; Streptococcus pyogenes; Virginiamycin

We evaluated the in vivo activity and the diffusion of radiolabelled RP 57669 (RPI) and RP 54476 (RPII), the two components of the injectable streptogramin RP 59500, alone or in combination, in aortic vegetations from experimental endocarditis in rabbits. RPI and RPII demonstrated in vitro bacteriostatic and bactericidal synergy against a clinical strain of Staphylococcus aureus resistant to methicillin and susceptible to erythromycin. In experimental staphylococcal endocarditis, RP 59500 was as effective as vancomycin and significantly more effective than RPI (P < 0.01) and RPII (P < 0.05). Autoradiography studies showed different patterns of distribution into cardiac vegetations infected with Streptococcus sanguis for [14C]RPI and [14C]RPII. [14C]RPI was homogeneously distributed throughout the vegetations whereas [14C]RPII showed a decreasing gradient of concentration between the periphery and the core of the vegetation, with an approximately 2:1 ratio. [14C]RPI diffused approximately 2 to 4 times more than [14C]RPII into the core of the vegetations. Since the injected ratio of RPI and RPII is 30:70 in RP 59500, the actual RPI:RPII ratio in the core of the vegetation may range from 0.8 to 1.7, a ratio which remains compatible with the in vivo synergism demonstrated between the two components.

Topics: Animals; Autoradiography; Culture Media; Drug Synergism; Endocarditis, Bacterial; Female; Humans; Methicillin Resistance; Microbial Sensitivity Tests; Rabbits; Staphylococcal Infections; Staphylococcus aureus; Streptococcal Infections; Streptococcus sanguis; Vancomycin; Virginiamycin

Pristinamycin, a member of streptogramin family, is the association of two groups (components I and pristinamycin II A) which have a high synergistic activity. Given the increasing rates of penicillin resistance in Streptococcus pneumoniae in many countries, and in particular of strains exhibiting multiple resistance to commonly used antibiotics, it was interesting to study the in vitro activity of pristinamycin against penicillin resistant S. pneumoniae (47 strains) and compare it with that of erythromycin. All strains were isolated from otitis media. Minimal inhibitory concentrations (MICs) were determined by an agar dilution technique using Mueller-Hinton medium supplemented with 5% horse blood. An inoculum of 10(4)-10(5) CFU per spot was delivered by a Steers replicator. This study showed that, among the 47 penicillin resistant strains, 29 (61.7%) were resistant to erythromycin but none of them were resistant to pristinamycin. The good in vitro activity of pristinamycin against S. pneumoniae could be of particular interest in cases of infections with multiresistant strains.

Topics: Dose-Response Relationship, Drug; Drug Resistance, Microbial; Erythromycin; Humans; In Vitro Techniques; Otitis Media; Penicillin G; Penicillin Resistance; Streptococcal Infections; Streptococcus pneumoniae; Virginiamycin

Within the framework of this symposium, it is not feasible to present an exhaustive description of the present state of knowledge regarding the sensitivity and resistance of bacterial species to macrolides, lincosamides and streptogramins (MLS). This paper is limited to a description of the evolution of different types of resistance in the light of decisive factors described in previous papers, in order to deduce, if at all possible, trends in future strategy in therapeutics. Only acquired resistance lends itself to epidemiological study, in contrast to natural resistance which is, by definition, characteristic of a species or a genus, and not liable to change. Three groups will therefore be studied in turn: Staphylococcus aureus, streptococci and Bacteroides fragilis. There is as yet insufficient accumulated data to draw conclusions regarding the epidemiology and evolution of MLSB resistance observed in Clostridium perfringens and Corynebacterium diphtheriae, or regarding the high-level resistance to erythromycin due to enzymatic inactivation recently described in Escherichia coli.

Topics: Anti-Bacterial Agents; Bacteroides; Bacteroides Infections; Biological Evolution; Drug Resistance, Microbial; Humans; Lincosamides; Macrolides; Phenotype; Species Specificity; Staphylococcal Infections; Staphylococcus; Staphylococcus aureus; Streptococcal Infections; Streptococcus; Streptococcus pyogenes; Structure-Activity Relationship; Virginiamycin

Micrococcin M, micrococcin M1 and eight micrococcin M derivatives, and two peptide antibiotics produced by micrococci and staphylococci were investigated for their antibacterial activity and therapeutic value. These antibiotics appeared to act solely on Gram-positive bacteria, especially on staphylococci and streptococci, in quite low concentrations in vitro and exerting both bacteriostatic and bactericidal effects. Gram-negative bacteria were virtually not susceptible. Resistance to micrococcins developed very rapidly, due to existence of numerous primarily resistant cells in sensitive populations. Complete cross-resistance resulted from acquiring resistance to one of the micrococcin antibiotics. Therapeutic effects are poor, as micrococcins are not absorbed from the injection site or from the intestinal tract after peroral administration. Importance of micrococcins in nature may be high, especially when ecology of normal bacterial flora and carriage of staphylococci and streptococci are concerned.

Topics: Animals; Bacitracin; Bacteriocins; Dogs; Drug Evaluation, Preclinical; Drug Resistance, Microbial; Erythromycin; Male; Mice; Microbial Sensitivity Tests; Micrococcaceae; Mycobacterium avium; Mycobacterium tuberculosis; Staphylococcal Infections; Streptococcal Infections; Time Factors; Virginiamycin

Topics: Animals; Anti-Bacterial Agents; Bacteriological Techniques; Clostridium; Culture Media; Drug Synergism; Enterobacteriaceae; Haemophilus; Leptospira; Malaria; Mice; Microbial Sensitivity Tests; Mycobacterium; Plasmodium; Protozoan Infections; Staphylococcal Infections; Streptococcal Infections; Toxoplasmosis; Trichomonas; Virginiamycin

Topics: Animals; Anti-Bacterial Agents; Bacteria; Drug Resistance, Microbial; Humans; Mice; Staphylococcal Infections; Staphylococcus; Streptococcal Infections; Virginiamycin

Topics: Anti-Bacterial Agents; Drug Resistance, Microbial; Drug Tolerance; Humans; Male; Middle Aged; Pyoderma; Staphylococcal Infections; Streptococcal Infections; Virginiamycin

Topics: Animals; Anti-Bacterial Agents; Mice; Staphylococcal Infections; Streptococcal Infections; Virginiamycin