RESUMO
The objective of the study was to assess the efficacy of meningococcal meningitidis vaccination among French military recruits, two years after the introduction of systematic vaccination. Protective efficacy (PE) was calculated using two epidemiological methods. The first was based on the incidence and density rates among vaccinated and unvaccinated subjects during the period when both groups were simultaneously available: PE = 100% (95% CI: 0-100%). The second was to compare the incidence density rates among vaccinated subjects with expected rates. The expected rates were calculated using a model involving adjustment of incidence rates observed before the introduction of vaccination. This second, more powerful method confirmed the efficacy of systematic vaccination for meningococcal meningitidis: PE = 100% (95% CI 30%-100%).
Assuntos
Vacinas Bacterianas/imunologia , Meningite Meningocócica/prevenção & controle , Militares , França , Humanos , Incidência , Estações do AnoRESUMO
OBJECTIVES: Antibiotic susceptibility of 649 gram-negative bacilli involved in severe infections and isolated in 18 teaching hospitals from January to December 1992 was evaluated. METHODS: Minimal Inhibitory Concentrations were determined by agar dilution method for piperacillin, piperacillin+ tazobactam and imipenem, and by a microdilution method for 11 other antibiotics (amoxicillin, amoxicillin + clavulanic acid, cefotaxime, ceftazidime, aztreonam, ticarcillin, ciprofloxacin, fosfomycin, tobramycin, gentamicin, amikacin). Criteria of Comité Français de l'Antibiogramme de la Société Française de Microbiologie were followed for interpretation. Betalactamases were identified by isoelectric focusing and overproduction of cephalosporinase was defined by the resistance phenotype. The main species isolated were Escherichia coli (45%), Pseudomonas aeruginosa (14%), Klebsiella pneumoniae (7.8%), Salmonella spp. (7.5%), Enterobacter cloacae (4%) and Klebsiella oxytoca (4%). Most of the strains were isolated from blood culture (72.3%), respiratory tract (11.4%) and intraabdominal infections (8.6%). Most of the enterobacteria isolates were susceptible to imipenem, aztreonam, amikacin and ciprofloxacin (percentages of susceptibility were respectively 99.3, 98, 98.3 and 96.3); in most of cases clavulanic acid did not entirely restore sensitivity to amoxicillin of penicillinase-producing strains. Among 89 P. aeruginosa strains, 82% were susceptible to imipenem and ceftazidime, 81% to the association piperacillin + tazobactam and 51% to ticarcillin. Resistance rates are very high for Acinetobacter baumannii except for imipenem. CONCLUSION: Production of TEM-type penicillinase and over-production of the chromosomal cephalosporinase are the most widely observed mechanisms of resistance (respectively 22% and 9% of 649 strains). Prevalence of extended spectrum betalactamases was low (1%) and essentially observed for K. pneumoniae.
Assuntos
Antibacterianos/farmacologia , Bactérias Aeróbias Gram-Negativas/efeitos dos fármacos , Infecções por Bactérias Gram-Negativas/microbiologia , Resistência Microbiana a Medicamentos , Quimioterapia Combinada/farmacologia , Hospitais Universitários , Humanos , Testes de Sensibilidade Microbiana , Estudos ProspectivosRESUMO
In spite of low endemic levels in France, hepatitis A and hepatitis B remain major concerns for public health. Seroprevalence of antibodies against hepatitis A (anti-HAV), declining below 15% in the 20 years-aged subjects, highlights an increasing susceptibility to hepatitis A. Later in the life, HAV infections become more serious and expansive. Control measures against hepatitis B have nearly stopped HBV spread linked to blood transfusions and mothers to infants transmission. Now, common risk factors are first sexual exposure, then injecting drug use, especially among young people. Vaccination is recognized as the most effective process for prevention. Recombinant hepatitis B vaccines have taken the place of plasma-derived vaccines. Although non responder individuals and escape mutants of HBV may hamper vaccinal coverage, hepatitis vaccines are highly immunogenic in immunocompetent people, allowing simplified schedules and reduced HBsAg dosages for children. Inactivated HAV vaccines now licensed prove to be highly immunogenic after only one injection. Hepatitis B vaccination targeted on high risk groups remains imperative but inadequate for reducing hepatitis B occurrence. A universal hepatitis B vaccination program in childhood and early adolescence would nearly stop the spread of HBV in the populations before ten years. Likewise, hepatitis A vaccination of travelers to endemic areas, all individuals exposed to contaminations from fecal sources, and food handlers, could reduce the spread of HAV in the community but would not completely prevent outbreaks of hepatitis A. Advantages of universal immunization of babies are not proved yet. Implementation of preventive strategies first needs a comprehensive surveillance of viral hepatitis in France.
Assuntos
Hepatite A/prevenção & controle , Vacinas contra Hepatite B , Hepatite B/prevenção & controle , Vacinas contra Hepatite Viral , Adolescente , Adulto , Criança , França/epidemiologia , Hepatite A/epidemiologia , Hepatite A/transmissão , Vacinas contra Hepatite A , Hepatite B/epidemiologia , Hepatite B/transmissão , Humanos , Recém-Nascido , Saúde Pública , Fatores de RiscoRESUMO
The bactericidal activity of 6 antibiotics and 3 combinations was evaluated against 6 Salmonella strains isolated from blood: 3 sensitive to all antibiotics tested (1 Salmonella Typhi, 1 Salmonella Paratyphi A et 1 Salmonella Enteritidis) and 3 harbouring a TEM penicillinase (1 Salmonella Typhi, 1 Salmonella Virchow et 1 Salmonella Typhimurium). MICs of 6 antibiotics, ceftriaxone, cefotaxime, cefoperazone, ciprofloxacin, amikacin and chloramphenicol were determined by microdilution method in Mueller Hinton broth. The bactericidal activity of these antibiotics and 3 combinations (ciprocloxacin + ceftriaxone, ciprofloxacin + amikacin and ceftriaxone + amikacin) was determined by the killing curve method with 10(6) cfu/ml inocula and 4 x MIC for antibiotics concentrations. Chloramphenicol, only tested on typho-paratyphi strains, had only a bacteriostatic effect at 24 hours. Amikacin and ciprofloxacin had a faster and better bactericidal activity than cephalosporins. Combinations were either additive or synergistic. Those including amikacin had the best results, but any can be proposed for initial treatment of severe Salmonella infections in immunosuppressed patients.
Assuntos
Cefoperazona/farmacologia , Cefotaxima/farmacologia , Ceftriaxona/farmacologia , Ciprofloxacina/farmacologia , Salmonella/efeitos dos fármacos , Amicacina/farmacologia , Antibacterianos/farmacologia , Cloranfenicol/farmacologia , Relação Dose-Resposta a Droga , Quimioterapia Combinada/farmacologia , Humanos , Técnicas In VitroRESUMO
Minimal inhibitory concentrations (MICs) of enoxacin (ENX), a new fluoroquinolone indicated for the treatment of urinary tract infections, was determined by agar dilution for 703 bacterial strains isolated in 1993 in 3 university hospitals in order to study its activity against urinary pathogens; in addition, antibiograms by agar diffusion were performed with 5 micrograms disks to calculate the regression curve and the breakpoints for sensitivity testing. Activity of ENX against nalidixic acid (NAL) susceptible (S) Enterobacteriaceae was close to that of other fluoroquinolones (FQ) (MIC 50 and 90: 0.25-0.5 microgram/ml); like for other FQ, this activity was reduced against NAL intermediate and resistant (R) Enterobacteriaceae (8-64) MICs of ENX against P. aeruginosa were between 0.5 and 128 (2- > 128). ENX had also a good activity against NAL-S A. baumannii (0.06-2) but this activity is reduced against NAL-R Acinetobacter (0.5- > 128). ENX showed activity close to the currently available FQ against methicillin susceptible Staphylococci (0.5-8); the resistant strains (32- > 64) are usually methicillin resistant. ENX is less effective against Enterococci (4-128). The coefficient correlation of the regression curve is 0.906. For MIC breakpoints of 1 and 2 micrograms/ml, zone diameter breakpoints should be 22 and 19 mm.
Assuntos
Acinetobacter/efeitos dos fármacos , Enoxacino/farmacologia , Enterobacteriaceae/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Pseudomonas aeruginosa/efeitos dos fármacos , Anti-Infecciosos/farmacologia , Relação Dose-Resposta a Droga , Resistência Microbiana a Medicamentos , Cocos Gram-Positivos/efeitos dos fármacos , Unidades Hospitalares , Humanos , Técnicas In Vitro , Análise de RegressãoRESUMO
Azithromycin is a new semisynthetic, acid stable C15 macrolid. In our study, we compared in vitro activity of azithromycin with 6 other antibiotics usually recommended for treatment of N. gonorrhoeae infections: erythromycin, ampicillin, amoxicillin, ceftriaxone, spectinomycin, ciprofloxacin. 100 strains have been selected: 95 clinical strains with different resistance patterns: 60 susceptible to beta-lactams, 25 PPNG, 10 chromosomal decreased susceptibility to beta-lactams. Among these strains, 13 had a decreased susceptibility to erythromycin (MIC: 2 and 4 mg/l) and 5 WHO reference strains: A: spectinomycin resistance, B: wild phenotype, C: chromosomal decreased susceptibility to penicillin and tetracycline, D: chromosomal resistance to penicillin and erythromycin+chromosomal decreased susceptibility to chloramphenicol, E: beta-lactamase producing strain (PPNG) and decreased susceptibility to tetracycline. MICs have been determined by GC agar dilution method. Azithromycin is more active than erythromycin on all N. gonorrhoeae patterns with a two log 10 difference for MIC50 and MIC90 (p < 0.0001). Because of pharmacokinetic properties and activity against Chlamydia trachomatis and urogenital mycoplasms often associated with N. gonorrhoeae, azithromycin is a good alternative for the treatment of genital infections.
Assuntos
Antibacterianos/farmacologia , Azitromicina/farmacologia , Eritromicina/farmacologia , Neisseria gonorrhoeae/efeitos dos fármacos , Relação Dose-Resposta a Droga , Resistência Microbiana a Medicamentos , Humanos , Técnicas In Vitro , Lactamas , Masculino , Neisseria gonorrhoeae/genéticaRESUMO
In spite of low endemic levels in France, hepatitis A and hepatitis B remains major concerns for public health. Seroprevalence of antibodies against hepatitis A (anti-HAV), declining below 15% in the 20 years-aged subjects, highlights an increasing susceptibility to hepatitis A. Later in the life, HAV infections become more serious and expansive. Control measures against hepatitis B have nearly stopped HBV spread linked to blood transfusions and mothers to infants transmission. Now, common risk factors are first sexual exposure, then injecting drug use, especially among young people. Vaccination is recognized as the most effective process for prevention. Recombinant hepatitis B vaccines have taken the place of plasma-derived vaccines. Although non responder individuals and escape mutants of HBV may hamper vaccinal coverage, hepatitis vaccines are highly immunogenic in immunocompetent people, allowing simplified schedules and reduced HBsAg dosages for children. Inactivated HAV vaccines now licensed prove to be highly immunogenic after only one injection. Hepatitis B vaccination targeted on high risk groups remains imperative but inadequate for reducing hepatitis B occurrence. A universal hepatitis B vaccination program in childhood and early adolescence would nearly stop the spread of HBV in the populations before ten years. Likewise, hepatitis A vaccination of travelers to endemic areas, all individuals exposed to contaminations from fecal sources, and food handlers, could reduce the spread of HAV in the community but would not completely prevent outbreaks of hepatitis A. Advantages of universal immunization of babies are not proved yet. Implementation of preventive strategies first needs a comprehensive surveillance of viral hepatitis in France.
Assuntos
Hepatite A/prevenção & controle , Vacinas contra Hepatite B , Hepatite B/prevenção & controle , Vacinas de Produtos Inativados , Vacinas contra Hepatite Viral , Vacinas contra Hepatite A , Humanos , Esquemas de ImunizaçãoRESUMO
The history of military medicine has always been closely linked with that of vaccinations. Doctors of Armed Forces, doctors of collectivities, have contributed to vaccination progresses in large amounts. But evolutions are often rapid here: epidemiological modifications, improvements in the existing vaccines or creation of new vaccines, diversification of military specificities. Three recent modifications in the vaccination schedule of the Armed Forces show this necessary adaptation: systematization of the meningococcal A+C vaccination during the incorporation, because of the modification of the disease's epidemiological profile; increase of the frequency in serogroup C with a mortality increase (9 cases of death out of 10 observed between 1991 and 1992); cancellation of antityphoid vaccination for recruits serving in home country. Indeed the disease has become rare in France, and this is often due to imported cases (3 cases in the Armed Forces in 1992); introduction in 1994 of vaccination against viral hepatitis A, systematic under the age of 25 years and after a serological selection above for servicemen having to serve overseas or for outside operations. These 3 examples show the necessity to have updated and adaptable vaccination schedules.
Assuntos
Hepatite A/prevenção & controle , Esquemas de Imunização , Meningite Meningocócica/prevenção & controle , Medicina Militar , Febre Tifoide/prevenção & controle , Vacinas Bacterianas/administração & dosagem , França , Vacinas contra Hepatite A , Hepatovirus/imunologia , Humanos , Vacinas Meningocócicas , Vacinas Tíficas-Paratíficas/administração & dosagem , Vacinação , Vacinas de Produtos Inativados/administração & dosagem , Vacinas contra Hepatite Viral/administração & dosagemRESUMO
Meropenem is a broad antibacterial spectrum carbapenem with a good activity on betalactam resistant Gram-negative bacilli. 120 non repetitive strains isolated from clinical samples from 1989 to 1992 were selected: 60 K. pneumoniae, 7 E. coli, 2 E. aerogenes and 1 S. marcescens with extended spectrum betalactamases (23 CTX-1, 18 SHV-2, 5 SHV-3, 16 SHV-4, 4 SHV-5, 3 CTX-1 + SHV-4, 1 CAZ-1), 10 K. pneumoniae with broad spectrum TEM-1 enzyme, and 40 K. pneumoniae with only SHV-1 chromosomal betalactamase. Determination of Minimal inhibitory concentrations (MIC) was done by agar dilution method for meropenem and 7 other betalactams (amoxicillin + clavulanic acid 2 mg/l, piperacillin + tazobactam 4 mg/l, cefoxitin, cefotetan, cefotaxime, ceftazidime, imipenem). All antibiotics except amoxicillin + clavulanic acid are active against strains with constitutive penicillinase. For strains with TEM-1 penicillinase, cephamycins, third generation cephalosporins and carbapenems are active. For strains with different extended spectrum betalactamases only cephamycins and carbapenems are efficious. There is no difference according to the period of isolation: 1989-90 or 1991-92. Meropenem has the best in vitro activity (MIC50 = 0.03 mg/l) for all strains independently of the nature of betalactamase.
Assuntos
Antibacterianos/farmacologia , Enterobacteriaceae/efeitos dos fármacos , Klebsiella pneumoniae/efeitos dos fármacos , Tienamicinas/farmacologia , beta-Lactamases/metabolismo , Carbapenêmicos/farmacologia , Relação Dose-Resposta a Droga , Enterobacteriaceae/enzimologia , Escherichia coli/efeitos dos fármacos , Técnicas In Vitro , Klebsiella pneumoniae/enzimologia , MeropenémRESUMO
Minimal inhibitory concentrations (MICs) of fleroxacin (FLE) were determined by agar dilution for 1261 bacterial strains isolated in 1992 in 4 university hospitals; in addition, antibiograms by agar diffusion were performed with 5 micrograms disks. Activity of FLE against nalidixic acid (NAL) susceptible (S) Enterobacteriaceae was close to that of other fluoroquinolones (FQ) (MIC 50 and 90: 0.12-0.25 micrograms/ml); like for other FQ, this activity was reduced against NAL intermediate and resistant (R) Enterobacteriaceae (4-32). MICs of FLE against P. aeruginosa were between 1 and 128 (8-128). FLE had also a good activity against NAL-S A. baumannii (0.12-0.5) but this activity is reduced against NAL-R Acinetobacter (64-128). FLE was highly active against Haemophilus (0.06-0.12), Gonococci (0.03-0.25), Meningococci (0.016-0.03) and B. catarrhalis (0.12-0.25). FLE showed activity close to the currently available FQ against methicillin susceptible Staphylococci (0.25-1); the resistant strains (32- > 128) are usually methicillin resistant. FLE is less effective against Enterococci (4-128), Streptococci (8-16) and Pneumococci (4-8). The coefficient correlation of the regression curve is 0.93; for MIC breakpoints of 1 and 4 micrograms/ml, zone diameter breakpoints should be 20 and 15 mm.
Assuntos
Enterobacteriaceae/efeitos dos fármacos , Fleroxacino/farmacologia , Bactérias Gram-Negativas/efeitos dos fármacos , Cocos Gram-Positivos/efeitos dos fármacos , Relação Dose-Resposta a Droga , Unidades Hospitalares , Técnicas In VitroRESUMO
The antibacterial activities of pefloxacin (PEF), ofloxacin (OFL), ciprofloxacin (CIP) were measured by agar diffusion (5 micrograms strength disks) against 6370 non duplicate clinical isolates collected in November 1991 in 40 hospitals from various areas in France. The MICs of PEF, OFL and CIP were determined by agar dilution against intermediate or resistant strains to one of the three antibiotics (inhibition zone < 16 mm for PEF, OFL, < 19 mm for CIP). In the Enterobacteriaceae the overall incidence of resistance to PEF (MIC > 4 mg/l) was 8% with important variations between the different species: E. coli 2%, Salmonella 0%, E. cloacae 9%, K. pneumoniae 21%, P. mirabilis 13%, P. vulgaris 3%, M. morganii 5%, Providencia 61%, S. marcescens 55%. Among S. aureus, the incidence of resistance was 3% for the methicillin-susceptible strains and 86% for the methicillin-resistant strains. The same applied to coagulase negative Staphylococci: methicillin-susceptible 9%, methicillin-resistant 62%. The frequency of the resistant strains was high among P. aeruginosa: 40% and A. baumanii: 83%. A high degree of correlation was observed between the MICs of PEF, OFL and CIP for all the bacterial species: r = 0.8 - 0.9. No major discrepancies were noted between the clinical categorizations of the activities of the three antibiotics for the different species except for P. aeruginosa: 4% of the strains were resistant to pefloxacin and susceptible to ciprofloxacin.
Assuntos
Ciprofloxacina/farmacologia , Bactérias Gram-Negativas/efeitos dos fármacos , Cocos Gram-Positivos/efeitos dos fármacos , Ofloxacino/farmacologia , Pefloxacina/farmacologia , Resistência Microbiana a Medicamentos , Enterobacteriaceae/efeitos dos fármacos , Unidades Hospitalares , Técnicas In Vitro , Resistência a MeticilinaRESUMO
The authors studied, with a time-kill curve method, in a derived Hafiz medium broth the bactericidal effect of 7 antibiotics and 4 associations against N. meningitidis. Their results show a better bactericidal effect for penicillin G, ampicillin and chloramphenicol. Pefloxacin and ceftriaxon are less efficient. The association ampicillin + chloramphenicol in vitro shows no antagonism and has a good bactericidal activity at the early stages of bactericidal killing with N. meningitidis.
Assuntos
Ampicilina/farmacologia , Cloranfenicol/farmacologia , Neisseria meningitidis/efeitos dos fármacos , Pefloxacina/farmacologia , Penicilina G/farmacologia , Ceftriaxona/farmacologia , Relação Dose-Resposta a Droga , Sinergismo Farmacológico , Quimioterapia Combinada/farmacologia , Técnicas In Vitro , Rifampina/farmacologia , Espiramicina/farmacologiaRESUMO
The E-test was evaluated by comparison with the reference agar dilution method on 50 N. meningitidis strains belonging to serotypes A [13], B [17] and C [12] or not agglutinated, isolated in France and Djibouti from cerebrospinal fluid. All strains were sensible by the reference method to penicillin G, cefotaxime, chloramphenicol, ciprofloxacin, doxycyclin, rifampicin. For erythromycin, some strains were intermediate (7/50). N. meningitidis serogroup A ATCC 13077 was used as control. The E-test quantitative accuracy compared with agar dilution results was 80% (+/- 1 log2) or 97% (+/- 2 log2). The E-test generally showed lower inhibitory concentration values than the agar dilution method. Some technical problems appear in our experience: agar plates must be well dried; on 85 mm diameter agar plates only one strip can be tested. The E-test for determination of antibiotic resistance of N. meningitidis is an easy but expensive method, which give reliable results with agar dilution.
Assuntos
Antibacterianos/farmacologia , Neisseria meningitidis/efeitos dos fármacos , Técnicas Bacteriológicas , Técnicas In VitroRESUMO
E-test was evaluated by comparison with the reference agar dilution method on 15 enterococci and 15 staphylococci with variable resistance to glycopeptides and isolated from clinical samples: 15 enterococci with 3 glycopeptide-resistant (2 E. facalis and 1 E. faecium), 1 glycopeptide intermediate E. gallinarum and 11 glycopeptide-sensible E. faecalis; 15 staphylococci with 4 teicoplanine-resistant (1 S. aureus, 1 S. epidermidis and 2 S. hominis), 3 teicoplanin-intermediate (1 S. epidermidis, 2 S. haemolyticus) and 8 teicoplanin sensible strains (6 S. aureus, 1 S. epidermidis and 1 S. hominis). Repeatability (10 determinations by strain) and exactitude were tested for all strains. Our data shows very good results for repeatability and exactitude with the reference method except in the case of coagulase negative staphylococci and teicoplanin. Some technical problems appear in our experience: for staphylococci, a 48 h incubation is necessary to detect teicoplanin-intermediate strains but 24 h is sufficient for enterococci. E-test is expensive, require a strict methodology, but is a good method to detect glycopeptide resistance for staphylococci and enterococci except for coagulase negative staphylococci and teicoplanine.
Assuntos
Enterococcus/efeitos dos fármacos , Staphylococcus/efeitos dos fármacos , Teicoplanina/farmacologia , Vancomicina/farmacologia , Técnicas Bacteriológicas , Resistência Microbiana a Medicamentos , Técnicas In VitroRESUMO
The interpretation of Gram-stained slides of vaginal swab specimens is evaluated for the diagnosis of bacterial vaginosis and correlated with the isolation bacteria and clinical signs: thin homogeneous vaginal discharge, pH > or = 4.7, amine odor and presence of clue cells. Gram stained smears were scored following a morphotype classification: (a)-Lactobacillus morphotypes (scored 4 to 0), (b)-small Gram negative (G. vaginalis, scored 0 to 4), (c)-curved Gram variable rods (Mobiluncus morphotypes, scored 0 to 2). The scoring system (0 to 10) was a weighted combination of these morphotypes: a+b+c. The criterion for bacterial vaginosis was a score > or = 7, a score of 0 to 6 was considered as no bacterial vaginosis. Samples of 709 women, aged 18 to 84 (mean age = 39.7) were examined. The prevalence of G. vaginalis culture was 12.5%, and Mobiluncus infection occurred in 1.5%. The frequency of M. hominis was diagnosed in 2.8% of women. A score of 7 to 10 on Gram stain was observed in 9.7% in the population. Compared to G. vaginalis culture, Gram stained smear was more sensitive (0.71) than clinical signs of bacterial vaginosis (0.46). The specificity was similar with the two methods. The assessment of G. vaginalis morphotypes was highly correlated with the G. vaginalis culture (p < 0.001, OR = 248). The infection of T. vaginalis or Candida sp. was never associated with a score > or = 7. The Gram-stained smear is a cheap, fast and easy method. It provides good results for diagnosis of bacterial vaginosis.
Assuntos
Infecções por Bacteroidaceae/diagnóstico , Gardnerella vaginalis/isolamento & purificação , Mobiluncus/isolamento & purificação , Esfregaço Vaginal/métodos , Vaginose Bacteriana/diagnóstico , Infecções por Bacteroidaceae/epidemiologia , Infecções por Bacteroidaceae/microbiologia , Feminino , França/epidemiologia , Humanos , Mycoplasma/isolamento & purificação , Infecções por Mycoplasma/diagnóstico , Infecções por Mycoplasma/epidemiologia , Infecções por Mycoplasma/microbiologia , Prevalência , Vaginose Bacteriana/epidemiologia , Vaginose Bacteriana/microbiologiaRESUMO
One hundred thirty-eight Staphylococcus aureus isolates from patients with severe staphylococcal infections were collected in 15 French hospitals. Detection of the mec gene was performed by dot blot hybridization with a specific DNA probe. Dot blot results were used to characterize the isolates as methicillin susceptible (77 isolates) or resistant (61 isolates). The isolates were screened for methicillin resistance by an agar spread method on Mueller-Hinton plates containing oxacillin (2 and 10 micrograms/ml) and were incubated at 37 degrees C, with 10(8) CFU as the inoculum. MICs of oxacillin and methicillin were determined by the agar dilution method on Mueller-Hinton plates without NaCl, by using 10(5) CFU per spot, after 24 and 48h of incubation at 30 or 37 degrees C. Moderately elevated MICs were found for 20 isolates (14.5%). The mec gene was detected in six (30%) of the isolates expressing a low level of resistance to methicillin and/or oxacillin. As determined by comparison with probe hybridization results, the spread plate method with oxacillin at 2 micrograms/ml was more sensitive (sensitivity, 100%) and specific (specificity, 100%) than agar dilution with either methicillin or oxacillin in identifying methicillin resistance or susceptibility. Determinations of methicillin and oxacillin MICs by the agar dilution method had a specificity of 99 to 100% depending on the conditions of incubation, but the sensitivity was below 85% whatever the duration or temperature of incubation.
Assuntos
DNA Bacteriano/genética , Genes Bacterianos , Resistência a Meticilina/genética , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/genética , Estudos de Avaliação como Assunto , França , Humanos , Testes de Sensibilidade Microbiana , Hibridização de Ácido Nucleico , Fenótipo , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/isolamento & purificaçãoRESUMO
The authors analysed the antibacterial activity of ceftibuten, cefotaxime, ceftazidime and aztreonam against Klebsiella pneumoniae strains, including those which produced novel extended-spectrum beta-lactamases. These molecules were also tested for their susceptibility to cell-free extracts of the corresponding beta-lactamases. Both approaches showed that ceftibuten was not hydrolysed by the CTX-1/TEM-3, SHV-2 and SHV-3 beta-lactamases, while cefotaxime, ceftazidime and aztreonam were hydrolysed. Nevertheless all compounds were substrates for the SHV-4 and SHV-5 beta-lactamases, and the organisms which produced these beta-lactamases showed increased MICs.