Isis Tamargo

Pedro Kourí Tropical Medicine Institute, La Habana, Ciudad de La Habana, Cuba

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Publications (6)12.09 Total impact

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    ABSTRACT: A simple, specific, sensitive and reproducible ELISA has been developed to quantify the level of CPS (capsular polysaccharide) production in supernatants of Streptococcus pneumoniae cell cultures. CPSs from Strep. pneumoniae have been widely used as vaccine antigens. The quantification method is based on two type-23F serotype-specific polyclonal antibodies: IgG, purified from sera of mice immunized with a pneumococcal type-23F CPS conjugate, used in the coating step, and a serotype-specific rabbit serum as the second antibody. Solutions of purified type-23F CPS were used as standards. The relationship between A(492) and type-23F CPS concentration was linear over the range 1-310 ng/ml (r=0.989), with 1 ng/ml as the lower limit of sensitivity. The specificity of ELISA was assessed because purified type-19F CPS and cell-wall polysaccharide samples were not detected after their evaluation by the ELISA described in the present study. Repeatability and intermediate precision of the assay were good, the coefficients of variation being 3 and 10% respectively. This ELISA allowed selection of an appropriate vaccine strain, for a natural polysaccharide vaccine, among several 23F pneumococcal clinical isolates and constituted a valuable analytical tool for Strep. pneumoniae fermentation and CPS purification follow-up.
    Biotechnology and Applied Biochemistry 06/2006; 44(Pt 2):101-8. DOI:10.1042/BA20060007 · 1.32 Impact Factor
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    ABSTRACT: A national surveillance study to determine antimicrobial susceptibility in Haemophilus influenzae type b isolated from cerebrospinal fluid was carried out in Cuba from 1990 to 2002. Susceptibility to ampicillin, co-amoxiclav, cefotaxime, ceftriaxone, co-trimoxazole, tetracycline, chloramphenicol and rifampicin was tested by the microdilution method according to the NCCLS guidelines. The 34 participating laboratories recovered 938 consecutive, non-identical isolates. All the isolates were retrieved from children aged <5 years. The mean number of isolates collected by year in the pre-vaccination era (1990-1998) was 93; after vaccination, 57 isolates were reported in 1999, 31 in 2000, four in 2001 and five in 2002. Resistance to ampicillin, co-trimoxazole, tetracycline and chloramphenicol was 46.3% (all beta-lactamase-positive), 51.3%, 33.2% and 44.0%, respectively. Ampicillin-resistant beta-lactamase-negative strains were not detected. All strains were susceptible to co-amoxiclav, cefotaxime, ceftriaxone and rifampicin. Ampicillin resistance was strongly associated with resistance to tetracycline, co-trimoxazole and chloramphenicol (P<0.001). Multidrug resistance was present in 43.8% of isolates. The most prevalent phenotype was resistance to ampicillin/chloramphenicol/tetracycline/co-trimoxazole, which was detected in 29.2% of strains overall. An increase in the prevalence of resistance to these antibiotics was observed from 1990 to 2000 in the range 40.7%-54.8% for ampicillin, 40.1%-51.6% for chloramphenicol, 45.4%-58.1% for co-trimoxazole and 23%-45.2% for tetracycline. In Cuba, the widespread vaccination against Haemophilus influenzae type b prevented a large number of meningitis cases in children caused by strains resistant to multiple antibiotics.
    Journal of Antimicrobial Chemotherapy 10/2003; 52(4):695-8. DOI:10.1093/jac/dkg395 · 5.44 Impact Factor
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    ABSTRACT: Recent but scarce reports of methicillin-resistant Staphylococcus aureus strains (MRSA) among children without risk factors associated with its acquisition prompted us to investigate its presence in the community. During the September and October months in 1997, nasal and pharyngeal swabs were obtained from 358 children aged less than five years who attended three day-care centers in the Marianao Area, La Habana City, Cuba. The isolated S. aureus strains were characterized for antimicrobial sensitivity using the Kirby-Bauer method. Methicillin resistance was confirmed by te Oxacillin Salt-Agar Screening-Plate method recommended by the National Committee for Clinical Laboratory Standards. 18.7% of children were carriers of S. aureus in the upper respiratory tract; 2.2% of children carried MRSA strains. The highest resistance levels corresponded to erythromycin (50.74%) and tetracycline (29.9%). All tested strains were sensitive to ciprofloxacin. Our results provide evidence on the recovery of MRSA strains among healthy children attending day-care centers and are suggestive of a rapid colonization and spread of these microorganisms in the community.
    Enfermedades Infecciosas y Microbiología Clínica 11/2001; 19(8):367-70. · 1.88 Impact Factor
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    ABSTRACT: Background Recent but scarce reports of methicillin-resistant Staphylococcus aureus strains (MRSA) among children without risk factos associated with its acquisition promted us to investigate its presence in the community Patients and Methods During the September and October months in 1997, nasal and pharyngeal swabs were obtained from 358 children aged less than five years who attended three day-care centers in the Marianao Area, La Habana City, Cuba. The isolated S. aureus strains were characterized for antimicrobial sensitivity using the Kirby-Bauer method. Methicillin resistance was confirmed by te ˝Oxacillin Salt-Agar Screening-Plate˝ method recommended by the National Committee for Clinical Laboratory Standards Results 18.7% of children were carriers of S. aureus in the upper respiratory tract; 2.2% of children carried MRSA strains. The highest resistance levels corresponded to erythromycin (50.74%) and tetracycline (29.9%). All tested strains were sensitive to ciprofloxacin Conclusions Our results provide evidence on the recovery of MRSA strains among healthy children attending daycare centers and are suggestive of a rapid colonization and spread of these microorganisms in the community.
    Enfermedades Infecciosas y Microbiología Clínica 01/2001; 19(8):367–370. DOI:10.1016/S0213-005X(01)72668-7 · 1.88 Impact Factor
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    Memórias do Instituto Oswaldo Cruz 07/1999; 94(4):477-8. DOI:10.1590/S0074-02761999000400008 · 1.57 Impact Factor
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    ABSTRACT: Meningitis caused by Haemophilus influenzae (Hi) is a serious disease that has high morbidity and mortality rates in many countries. Approximately 99% of Hi invasive infections are caused by H. influenzae b (Hib). Its worldwide incidence in infants varies widely according to different regions of the world (AC Moloney et al. 1997 Infect Dis 16: 123-126).