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Revista espanola de quimioterapia: publicacion oficial de la Sociedad Espanola de Quimioterapia 09/2012; 25(3):220-1. · 0.81 Impact Factor
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ABSTRACT: The aim of this study is to describe the distribution of Streptococcus pneumoniae serotypes, its antimicrobial susceptibility profiles and the relation with vaccines in pneumococcal invasive strains isolated from blood cultures of adult patients.
All pneumococci isolated (67 strains) from blood cultures were serotyped by latex agglutination (Pneumotest latex) and Quellung reaction (Statens Serum Institut, Denmark). Antimicrobial susceptibility testing to penicillin (PEN), cefotaxime (CT), erythromycin (ERY) and levofloxacin (LEV) was performed by the E-test method (Biomèrieux, France).
Among the 67 strains isolated, the most prevalent serotypes were 22F (11.9%) and 3 (11.9%), the second most frequent were 7F (7.5%) and 19A (7.5%). The coverage of the strains by the pneumococcal 7-valent conjugate vaccine (VNC7V), pneumococcal 13-valent conjugate vaccine (VNC13V) and pneumococcal 23-valent polysaccharide (VNP23V) were 16, 49 and 82%, respectively. Serotypes 22F and 3 were responsible for 14 of the 48 episodes of pneumonia with bacteremia (29.2%) and only 2 of the 19 episodes (10.5%) of bacteremia without pneumonia. According to the 2007 CLSI criteria, 12 strains (17.9%) were non-susceptible to penicillin. Eleven of this 12 strains (91.7%) were resistant to erythromycin, simultaneously.
The most common serotypes were 22F, 3, 7F y 19A. Three of them (3, 7F y 19A) are serotypes that are covered by the new VNC13V but not by VNC7V. Serotype 22F is a serotype emergent that is not covered by the VNC7V. The percentage of non-susceptibility to penicillin and resistance to erythromycin was comparable to the percentage reported in our country.
Revista espanola de quimioterapia: publicacion oficial de la Sociedad Espanola de Quimioterapia 06/2012; 25(2):155-60. · 0.81 Impact Factor
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ABSTRACT: Lipophilic corynebacteria are part of the saprophytic skin flora and they rarely cause infection. C. macginleyi is an exception since it has been involved in conjunctivitis and other ocular surface affections.
Thirty three C. macginleyi strains were obtained from conjunctival swabs from patients with conjunctivitis symptoms. The minimum inhibitory concentration (MIC) for 7 antibiotics (penicillin, gentamycin, ciprofloxacin, tetracycline, vancomycin, rifampicin and linezolid) was tested by broth microdilution method.
One strain was resistant to ciprofloxacin (MIC=16 mg/L) and two were resistant to tetracycline (MIC= 64 y 16 mg/L). The rest of the strains were susceptible to all the antibiotics tested.
At the moment, C. macginleyi does not present a major problem due to the low resistance rates shown in the present and other studies. However, epidemiological surveillance of its susceptibility pattern is needed as well as an appropriate use of topical antibiotics in order to achieve a good infection control.
Revista espanola de quimioterapia: publicacion oficial de la Sociedad Espanola de Quimioterapia 12/2010; 23(4):196-200. · 0.81 Impact Factor
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Revista espanola de quimioterapia: publicacion oficial de la Sociedad Espanola de Quimioterapia 07/2007; 20(2):170-81. · 0.81 Impact Factor
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ABSTRACT: Helicobacter pylori possess various virulence factors, including cagA and vacA genes, that are associated with more aggressive symptoms such as bleed-ing ulcer and gastric cancer. Although there are different treatment regimens, there is still a failure rate of up to 20% due to antibiotic resistance, among other causes. In our country resistance to metronidazole and clarithromycin is increasing, especially in children, although they are still susceptible to amoxicillin and tetracycline. In order to determine the susceptibility pattern to these antibiotics 36 H. pylori clinical isolates were studied. MIC was determined by agar diffusion and agar dilution, and vacA and cagA genes were detected by conventional PCR. All isolates were susceptible to amoxicillin and tetracycline. Resistance to metronidazole by diffusion or dilution tests was 35.7% and 36.1%, respectively, and to clarithromycin, 21.4% and 22.3%, respectively. There was one strain that showed intermediate resistance to clarithromycin (MIC 0.38 mg/l), using agar diffusion, and that was included among the resistant strains. Three discrepancies were observed between the diffusion and dilution methods. The vacA s1 allele was detected in 17.2% of the strains, and vacA s2 in 82.8%; 51.7% of the total were cagA+. In conclusion, all strains tested in our study were susceptible to amoxicillin and tetracycline, allowing them to be considered as first-line antibiotics, while clarithromycin and metronidazole maintain a slight increase in their resistance level. The cagA+ strains were detected in expected quantities, while the s1 allele of the vacA gene was detected in lower quantities.
Revista espanola de quimioterapia: publicacion oficial de la Sociedad Espanola de Quimioterapia 04/2006; 19(1):34-8. · 0.81 Impact Factor
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ABSTRACT: Clarithromycin, amoxicillin, tetracycline and metronidazole are the most frequently used antimicrobials for Helicobacter pylori infection treatment. While tetracycline and amoxicillin resistance are rare, clarithromycin and metronidazole resistance vary in different populations and are considered factors for treatment failure. The aim of this study was to determine the in vitro activity of furazolidone and nitrofurantoin in 164 H. pylori clinical isolates by agar dilution and to determine the spontaneous mutation rate. Metronidazole and clarithromycin resistance were 23.77% (CI95%: 18.96-29.14) and 16.78% (CI95%: 12.64-21.62), respectively; moreover, 1.4% (CI95%: 0.38-3.54) were intermediate to clarithromycin. All the isolates were susceptible to amoxicillin and tetracycline. Furazolidone and nitrofurantoin resistance rates were 1.82% (CI95%: 0.37-5.25) and 0.6% (CI95%: 0-3.35), respectively. The three furazolidone-resistant strains were nitrofurantoine-susceptible (MIC 4 mg/l for furazolidone and 2 mg/l for nitrofurantoin) and the nitrofurantoin-resistant strains were furazolidone-susceptible (MIC 4 mg/l for nitrofurantoin and 1 mg/l for furazolidone). These four strains were metronidazole-resistant (MIC 16 mg/l). Furazolidone or nitrofurantoin spontaneous mutants were not detected in the eight H. pylori strains tested. However, mutants with resistance to metronidazole were found with all the strains with a mutation rate of 7.4 x 10(-10) to 9.4 x 10(-10). Furazolidone and nitrofurantoin showed an excellent in vitro activity against the H. pylori clinical isolates included herein, supporting the usefulness of furazolidone as second-line antimicrobial after treatment failure or as first-line therapy in populations with low economical resources.
Revista espanola de quimioterapia: publicacion oficial de la Sociedad Espanola de Quimioterapia 01/2006; 18(4):313-8. · 0.81 Impact Factor
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ABSTRACT: Tuberculosis is considered a serious public health problem. Some factors, such as HIV infection and immigration, have had a major impact on the epidemiology of this illness in Spain. The problem has worsened in recent years due to the dissemination of multiresistant strains. Therefore, a periodic surveillance should be established with respect to the incidence and the resistances observed. In this study we collect M. tuberculosis isolates carried out in the years 2001, 2002, 2003 and 2004, and their susceptibility characteristics in patients from Area 2 in Madrid. To evaluate the isolates' susceptibilities, the MGIT 960 system was used. Of a total of 244 isolates, 15.2% were resistant to at least one antibiotic (different to streptomycin), and 29.9% of the isolates were obtained in samples from immigrant patients. In addition, the immigrant population affected showed a greater percentage of resistances (p <0.01) and a younger mean age (p <0.01) than the indigenous population.
Revista espanola de quimioterapia: publicacion oficial de la Sociedad Espanola de Quimioterapia 10/2005; 18(3):222-5. · 0.81 Impact Factor
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Revista espanola de quimioterapia: publicacion oficial de la Sociedad Espanola de Quimioterapia 01/2004; 16(4):385-93. · 0.81 Impact Factor
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Clinical Microbiology and Infection 07/2003; 9(6):576-7. · 4.54 Impact Factor
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ABSTRACT: This study aimed to identify the activity of eight antibiotics (ofloxacin, moxifloxacin, azithromycin, erythromycin, clindamycin, ampicillin, amoxicillin-clavulanic acid and tetracycline) against 80 strains of Campylobacter jejuni isolated from children. Minimal inhibitory concentrations (MIC) were determined by an agar dilution method. Resistance to azithromycin and erythromycin was considered when MIC > or =8 mg/l, to clindamycin when MIC > or =1 mg/l, to amoxicillin-clavulanic acid and ampicillin when MIC > or =32 mg/l, to ofloxacin and moxifloxacin when MIC > or =4 mg/l, and to tetracycline when MIC > or =16 mg/l. All strains tested were susceptible to amoxicillin-clavulanic acid. The lowest frequency of resistance was to azithromycin (2%), erythromycin (3.7%), clindamycin (4.4%) and ampicillin (4.9%), and the highest was to ofloxacin and tetracycline (61.7% for both), and moxifloxacin (37%). Considered the antibiotics of choice for the treatment of infections caused by this microorganism, macrolides showed excellent activity with MIC(90)=0.5 mg/l for azithromycin and MIC(90)=0.5 mg/l for erythromycin.
Revista espanola de quimioterapia: publicacion oficial de la Sociedad Espanola de Quimioterapia 07/2003; 16(2):216-20. · 0.81 Impact Factor
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ABSTRACT: Several methods have been used to detect clarithromycin resistance. Agar dilution is now recommended by the NCCLS (susceptible to clarithromycin: MIC<=0.25 mg/l; intermediate resistance: MIC=0.5 mg/l; resistant: MIC>=1 mg/l), and the detection of mutations involved in resistance is used in many laboratories. We analyzed 36 clarithromycin-resistant strains isolated from children and 30 from adults. In vitro susceptibility to clarithromycin was determined by an agar dilution method. DNA from the isolates was extracted using the method published by Ge and Taylor. A2142G and A2143G mutations were identified by PCR-RFLP. A 1.4 Kpb of the 23S rRNA gene was amplified and digested using MboII or BsaI restriction enzymes to detect mutations. The prevalence of the A-G transition mutation at position 2143 was higher in the children (80.55%) than in the adult patients (46.66%) (p<0.05); however, the prevalence of the mutation at position 2142 was higher in adults than in children (36.66% vs. 5.55%; p<0.05). In children, a higher MIC (2-64 mg/l) was observed when the A-G mutation was detected at position 2143. However, in adult patients higher MICs were observed when the A-G mutation was detected at position 2142.
Revista espanola de quimioterapia: publicacion oficial de la Sociedad Espanola de Quimioterapia 04/2003; 16(1):53-7. · 0.81 Impact Factor
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ABSTRACT: The aim of this study was to determine the in vitro activity of clarithromycin and metronidazole using an agar dilution method to compare two different incubation atmospheres: a CO2 incubator and a jar with a microaerobic gas-generating system. Antibiotics were placed on plates in twofold dilutions ranging from 128 to 0.064 mg/l in Mueller-Hinton agar supplemented with 7% horse blood. The inoculum was prepared from 31 Helicobacter pylori isolates and was inoculated using a Steers replicator. Plates were incubated for 3 to 5 days and MICs were recorded as the lowest concentration of antibiotic inhibiting visible growth. Two different incubation atmospheres were used: a CO2 incubator set at 95% humidity and 10% CO2, and a jar with a gas-generating envelope that produces 7-10% O2 and 14% CO2 (BioMerieux). Clarithromycin resistance was found in 19% of strains both in the gas-generating system and the CO2 incubator. Metronidazole resistance was 23% in both atmospheres. MICs for clarithromycin in both atmospheres showed two dilutions of difference for 100% of the strains, and were slightly higher in the jar with a gas-generating envelope. However, MICs for metronidazole were higher when it was incubated in the CO2 incubator, and in 86.7% of strains the MICs showed < or = 2 dilutions of difference. No great discrepancies were found for either metronidazole or clarithromycin using the two methods.
Revista espanola de quimioterapia: publicacion oficial de la Sociedad Espanola de Quimioterapia 12/2002; 15(4):341-5. · 0.81 Impact Factor
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ABSTRACT: The evolution of clarithromycin, metronidazole and amoxycillin resistance in 246 Spanish Helicobacter pylori clinical isolates, obtained from paediatric patients during a 9 year period, was determined by an agar dilution technique. Clarithromycin resistance (MIC 1 mg/L) was 2.27% (IC95 0.05-12.02) in 1991-1993, 20.98% (IC95 12.72-31.46) in 1994-1996 and 28.33% (IC95 20.48-37.28) in 1997-1999 (P < 0.01). Metronidazole resistance (MIC 8 mg/L) was 7.14% (IC95 1.49-19.48) in 1991-1993, 20.25% (IC95 12.04-30.79) in 1994-1996 and 43.90% (IC95 32.95-55.30) in 1997-1999 (P < 0.01). Amoxycillin resistance was not found (all strains showed MICs < 2 mg/L).
Journal of Antimicrobial Chemotherapy 09/2001; 48(2):295-7. · 5.07 Impact Factor
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ABSTRACT: The aim of this study was to determine the in vitro activity of ascorbic acid (vitamin C) against 43 Helicobacter pylori clinical isolates obtained from gastric biopsy taken by endoscopy. The MIC was determined by an agar dilution method. The ascorbic acid was included as two-fold dilutions in the agar to obtain a final concentration from 4000 mg/l to 62 mg/l. Brain-heart infusion agar supplemented with yeast extract and 10% fetal calf serum, 10(6) CFU/spot inoculum and microaerobic incubation for 2 to 5 days were used. MIC(50) 500 mg/l, MIC(90) 1000 mg/l and the range from 62 to 2000 mg/l. No differences in susceptible or resistant isolates were observed. Ascorbic acid showed good in vitro activity against the H. pylori clinical isolates tested in this study, which could explain some of the beneficial properties of vitamin C.
Revista espanola de quimioterapia: publicacion oficial de la Sociedad Espanola de Quimioterapia 01/2001; 13(4):408-11. · 0.81 Impact Factor
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Enfermedades Infecciosas y Microbiología Clínica 12/2000; 18(9):488-90. · 1.49 Impact Factor
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ABSTRACT: Thirty clarithromycin-resistant Helicobacter pylori strains (MIC range 8-64 mg/L) were subcultured in a drug-free medium and the MIC was determined every five passages to detect in vitro stability of resistance. Three out of the 30 (10%) lost their resistance after 10, 13 or 18 subcultures (MIC decrease from 8 to 0.008, from 16 to 0. 064 and from 32 to 0.016 mg/L). The effect of four macrolides at subinhibitory concentrations on the development of resistance was studied in H. pylori NCTC 11638 and TIGR 26695. A change in the MIC was observed only when NCTC11638 was exposed to 0.5 x MIC of erythromycin for 20 days.
Journal of Antimicrobial Chemotherapy 11/2000; 46(4):613-6. · 5.07 Impact Factor
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ABSTRACT: VacA and CagA serological responses were detected in pediatric patients: 44 and 56%, respectively, in peptic ulcer (PU) patients, 33.3 and 44.4% in active chronic gastritis (ACG) patients, and 23.2 and 39.2% in non-ACG patients. Higher seroprevalence to CagA+VacA and to CagA+VacA+35-kDa antigen was found among PU patients. However, a low level of sensitivity and specificity was found for indirect detection of PU patients.
Clinical and Diagnostic Laboratory Immunology 10/2000; 7(5):842-4. · 2.51 Impact Factor
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ABSTRACT: Twenty-five clarithromycin-resistant Helicobacter pylori strains (selected by agar dilution) were studied to detect A2142G and A2143G mutations in the 23S rRNA gene by a PCR-restriction fragment length polymorphism method and an A2142C mutation by PCR using a 3'-mismatched specific primer. A 700-bp amplified fragment was obtained by the mismatched PCR only in strains without an A2142G or A2143G mutation, indicating that those strains had the A2142C mutation.
Journal of Clinical Microbiology 03/2000; 38(2):923-5. · 4.15 Impact Factor
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Journal of Clinical Microbiology 07/1999; 37(6):2113-4. · 4.15 Impact Factor
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ABSTRACT: The eradication rate obtained using the classical triple therapy containing metronidazole, amoxicillin and bismuth citrate, was determined in 57 paediatric patients with digestive disorders, according to the susceptibility to metronidazole of the Helicobacter pylori strains (determined by agar dilution) and the cagA and vacA status (determined by PCR). Eradication was obtained in 38 out of 43 patients (88.3%) infected by H. pylori with metronidazole MIC < or = 2 mg l(-1), in 3 out of 6 patients (50%) when MIC was 4-8 mg l(-1) and in 4 out of 8 patients (50%) when MIC was > 8 mg l(-1). Among patients infected with cagA+ and cagA- strains an eradication rate of 75% (6/8) and 75% (18/24) was found, and 50% (3/6) and 80% (21/26) among vacA s1- and vacA s2-infected subjects (P > 0.05). H. pylori eradication depends on the susceptibility of the strain to metronidazole, being higher in patients infected with susceptible H. pylori. However, according to our data the cagA or vacA status was not an important factor in treatment failure in the eradication of H. pylori.
FEMS Immunology & Medical Microbiology 07/1999; 24(2):183-8. · 2.44 Impact Factor
