[Phenotypes and genetic mechanisms of resistance to macrolides and lincosamides in viridans group streptococci]. / Fenotipos y mecanismos genéticos de resistencia a macrólidos y lincosamidas en estreptococos del grupo viridans.

Viridans group streptococci (VGS) are part of the oropharyngeal, intestinal and genital flora, but they may cause endocarditis and bacteremia in susceptible patients. Penicillin- and macrolide-resistant strains are increasing every year. The aim of this study was to investigate genetic mechanisms of resistance to macrolides in clinically relevant isolates. We identified 85 isolates from January 2004 to June 2006. Susceptibility to penicillin, cefotaxime, erythromycin, clindamycin and gentamycin was determined. A resistance phenotype was assigned according to the disk approximation test (erythromycin-clindamycin). The mechanism of resistance was determined by PCR for the following genes: ermB, ermA, ermC, ermA (TR) and mefA/E. We identified 51 isolates belonging to Streptococcus anginosus species, most of which were obtained from abdominal abscesses, and 34 isolates belonging to other species, most of which were obtained from blood cultures. The macrolide resistance rate was 28.2% (24/85). The MLS(B) phenotype was observed in 66.7% of the isolates, primarily in the S. anginosus group. The M phenotype was predominant in S. mitis and S. oralis. Isolates that expressed the constitutive MLS(B) phenotype carried the ermB gene, and those that expressed the inducible MLSB phenotype carried the ermA gene. Isolates that expressed the M phenotype carried the mefA/E gene. There was coresistance with penicillin in 20.8% (5/24) of the isolates. Coresistance with penicillin was low. These results suggest that screening for macrolide resistance in VGS would be desirable because of the potential transmission of resistance genes to other pathogenic streptococci.

Fenotipos y mecanismos genéticos de resistencia a macrólidos y lincosamidas en estreptococos del grupo viridans / Phenotypes and genetic mechanisms of resistance to macrolides and lincosamides in viridans group streptococci

Los estreptococos del grupo viridans forman parte de la flora orofaríngea, intestinal y genital, pero pueden causar endocarditis y bacteriemia en pacientes susceptibles. Cada vez se describen más cepas resistentes a las penicilinas y a los macrólidos. El objetivo de nuestro estudio fue conocer los mecanismos de resistencia a los macrólidos en aislamientos con significación clínica. De enero de 2004 a junio de 2006 se identificaron 85 cepas de estreptococos del grupo viridans. Se determinó la sensibilidad a penicilina, cefotaxima, eritromicina, clindamicina y gentamicina. Se estableció el fenotipo de resistencia a los macrólidos mediante aproximación de discos (eritromicina-clindamicina). Se detectó el mecanismo genético de resistencia mediante PCR para los genes ermB, ermA, ermC, ermA (TR) y mefA/E. Se identificaron 51 cepas pertenecientes a especies del grupo anginosus, obtenidas mayoritariamente de abscesos abdominales, y 34 cepas de otras especies, obtenidas mayoritariamente de hemocultivos. La tasa de resistencia a los macrólidos fue del 28,2% (24/85). El fenotipo MLSB se observó en el 66,7% de las cepas, principalmente del grupo anginosus. El fenotipo M predominó en S. mitis y S. oralis. En las cepas con fenotipo MLSB constitutivo se detectó el gen ermB, mientras que en las cepas con expresión inducible se detectó el gen ermA. En las cepas con fenotipo M se detectó el gen mefA/E. Se observó corresistencia con penicilina en el 20,8% (5/24) de las cepas. La resistencia a los macrólidos en los estreptococos del grupo viridans es ligeramente menor que la observada en otros estudios. Destacamos mayor resistencia y presencia del fenotipo MLSB en cepas del grupo anginosus, y del fenotipo M en las restantes especies, lo cual podría estar relacionado con el origen anatómico de las cepas. La corresistencia a la penicilina fue baja. Sería recomendable vigilar periódicamente la resistencia a los macrólidos en los estreptococos del grupo viridans, posibles transmisores de resistencia a otras especies de estreptococos patógenos

Viridans group streptococci (VGS) are part of the oropharyngeal, intestinal and genital flora, but they may cause endocarditis and bacteremia in susceptible patients. Penicillin- and macrolide-resistant strains are increasing every year. The aim of this study was to investigate genetic mechanisms of resistance to macrolides in clinically relevant isolates. We identified 85 isolates from January 2004 to June 2006. Susceptibility to penicillin, cefotaxime, erythromycin, clindamycin and gentamycin was determined. A resistance phenotype was assigned according to the disk approximation test (erythromycin-clindamycin). The mechanism of resistance was determined by PCR for the following genes: ermB, ermA, ermC, ermA (TR) and mefA/E. We identified 51 isolates belonging to Streptococcus anginosus species, most of which were obtained from abdominal abscesses, and 34 isolates belonging to other species, most of which were obtained from blood cultures. The macrolide resistance rate was 28.2% (24/85). The MLSB phenotype was observed in 66.7% of the isolates, primarily in the S. anginosus group. The M phenotype was predominant in S. mitis and S. oralis. Isolates that expressed the constitutive MLSB phenotype carried the ermB gene, and those that expressed the inducible MLSB phenotype carried the ermA gene. Isolates that expressed the M phenotype carried the mefA/E gene. There was coresistance with penicillin in 20.8% (5/24) of the isolates. Coresistance with penicillin was low. These results suggest that screening for macrolide resistance in VGS would be desirable because of the potential transmission of resistance genes to other pathogenic streptococci

[Survey of carriers of Neisseria meningitidis in the health area of Gran Canary]. / Encuesta de portadores de Neisseria Meningitidis en el Area de Salud de Gran Canaria.

BACKGROUND: A) To ascertain the rate of carriers and the Types of Neisseria Meningitidis circulating in the population resident in the health jurisdiction of Gran Canaria. B) to ascertain the pattern of distribution of such carriers. METHODS: A descriptive transversal design was made, with a random sampling in multiple stages and by conglomerates. A minimum sample size was determined at 707 individuals for an expected prevalence of 8.6%, with a rate of reliability of 95.6% and a precision of 0.02. Assuming that 15% if the individuals would not be willing to co-operate, the sample size was increased to 831 individuals, distributed in each conglomerate in proportion to the existing population. This size was distributed in turn into four groups by age and sex, in proportion to their significance in each basic health care zone selected at random. The individuals in the sample were identified from among those who attended the blood extraction units, and after they had passed the criteria of exclusion, their co-operation was requested as volunteers in the study. If they accepted, a questionnaire was filled out with a number of variables of epidemiological interest and a pharyngeal smear was taken. Since the Primary Care units were selected on a simple random basis, and the same method was used to select the individuals within the units, the estimate of the prevalence was made by means of an unbiased estimator. RESULTS: A total of 828 samples were obtained, that is, 99.6% of the number foreseen. With the exception of three, all of the individuals selected participated voluntarily in the study, a circumstance rendering it highly representative. All of the strains obtained corresponded to N. Meningitidis Serogroup B, except for one identified as N. Meningitidis Serogroup C Sero/Subtype 4:P1.2,5. The strains of N. Meningitidis serogroup B identified corresponded to 25 different sero-subtypes. The prevalence determined after having studied the sample was 6.45%, the variance = 0.0275 and the standard error = 1.66. We can conclude with a 95% degree of reliability that the prevalence of carriers of N. Meningitidis in the Gran Canaria health jurisdiction is estimated to be between 3.2% and 9.7%. CONCLUSIONS: A clear predominance of N. Meningitidis serogroup B strains among carriers has been verified. There are no statistically significant differences in the prevalence observed among the different age groups nor between sexes.

[Tuberculosis en pediatric patients in the island of Gran Canaria]. / Tuberculosis en pacientes pediátricos en la isla de Gran Canaria.

OBJECTIVE: Tuberculosis is still an important sanitary problem in our country, which has a high rate of endemia. The pediatric population is highly susceptible to being exposed and has a high risk of developing the disease, as well as of suffering serious forms of it. The aim of this study was to analyze the clinical aspects and characteristics of pediatric patients who were diagnosed with tuberculosis in Gran Canaria during a nine years period. PATIENTS AND METHODS: The clinical charts of 49 children between 0 and 14 years of age who were diagnosed of having tuberculosis between 1986 and 1994 were revised. Tuberculosis was diagnosed when M. tuberculosis was isolated from at least one clinical sample. RESULTS: Of the children diagnosed, 69.4% were less than 5 years of age. Only one child had antibodies against HIV. Clinical forms were; pulmonary (33 cases), disseminated (13 cases), genitourinary (1 case), osteoarticular (1 case), and lymphatic (1 case). No association was found between any clinical form and any age group. The disseminated form presented more frequently with a negative Mantoux test (p < 0.01). In all cases lung disease was present and three patients also suffered meningitis. In most of the cases (77.8%), it was necessary to wait for the result of the culture to reach the diagnosis. Two children (4.1%) died and six (12.2%) had sequeale. CONCLUSIONS: Disseminated tuberculosis is relatively frequent (26.5%) in this population and is usually associated with a negative Mantoux test. Therefore, it appears that in this serious form of the disease, a high degree of clinical suspicion is needed and mycobacteria cultures must be done in clinical samples of different origins.

[Clinical and epidemiological survey of RSV infection in infants]. / Estudio clínico-epidemiológico de la infección por virus respiratorio sincitial en el lactante.

OBJECTIVE: A prospective study was performed to assess the clinical and epidemiological characteristics of RSV infections in hospitalized infants. PATIENTS AND METHODS: Between October 1988 and September 1991, we studied 322 cases of RSV respiratory infections diagnosed by EIA of nasopharyngeal lavage and/or serology by complement fixation. Clinical, analytical and radiological data were reviewed. RESULTS: Time-analysis showed higher incidences of RSV infections in December, January, November and February, with an increase in hospital admissions due to respiratory problems before the peak in RSV infections. The mean age of the population was 6.84 +/- 7.07 months. The mean weight was 7.4 +/- 2.68 kg and the sex distribution was 61.2% males and 38.8% females. Blood count was not useful in the differential diagnosis between bronchiolitis/bronchitis and pneumonias, but the erythrocyte sedimentation rate was higher in the last group (25.2 +/- 20.1 versus 38.2 +/- 29.5, t = 2.52, p < 0.05). Clinical status, with a mean value of 6.09 +/- 2.31 as assessed by the modified Downes's Score, showed a significant relationship with the time of hospitalization (mean: 8.77 days; r = 0.2108, p < 0.01), but not with gas exchange, weight or age. Chest X-rays showed air trapping in 48% of the cases, but the incidence of condensation was lower than in other series (16%), probably because we do not believe that any infiltration of the lungs on chest roentgenograms places the patients in the pneumonia category. CONCLUSIONS: We found a high frequency of RSV infection among hospitalized infants and there was seasonal variation with a higher incidence during the winter months.

[Epidemiology of respiratory syncytial virus infections in the Canary Islands]. / Epidemiología de la infección por virus respiratorio sincitial en las islas Canarias.

Respiratory syncytial virus (RSV) is the major cause of lower respiratory tract infection in young children. Outbreaks of RSV infection occur yearly during the winter or spring in temperate climates. Our study of 634 hospitalized children under 3 years of age with bronchiolitis and pneumonia (November 1988 to January 1990) revealed that 227 (35.8%) had VRS infections. These cases showed a yearly epidemic pattern with 86.8% of the cases occurring during the winter. Furthermore, 67.4% of the cases occurred in children between 1-6 months of age and the boy/girl ration was 1.2/1. In 26.9% of the infections there was an antibody response. These results for RSV infection on this island show the same epidemiological pattern as that in the temperate climates.

Reliability of the bronchoscopic protected catheter brush in the diagnosis of pneumonia in mechanically ventilated patients.

OBJECTIVE: To assess the usefulness of the telescoping plugged catheter in the diagnosis of nosocomial pneumonia. DESIGN: Prospective study. PATIENTS: A total of 103 ventilated patients with suspected pneumonia were prospectively studied over 20 months. RESULTS: The quantitative cultures of the protected brush specimen detected pulmonary bacterial infection (greater than 10(3) cfu/mL) in 49 (47.5%) patients. Subsequent follow-up confirmed pneumonia in 41 patients; in only one patient was a positive protected brush specimen culture established as a false-positive result. There were 54 patients with less than 10(3) cfu/mL and the diagnosis was excluded in 36 of them. We identified eight patients with false-negative protected brush specimen cultures. The results obtained by this technique allowed us to modify treatment in 49 (47.5%) patients. CONCLUSIONS: The telescoping plugged catheter demonstrated significant bacterial infection in a relatively small proportion of patients in whom bacterial lung infection was suspected. This technique can be safely performed and is a sensitive and specific method to establish the cause of pneumonia, thus allowing specific treatment and the avoidance of inappropriate antibiotic therapy.

[The usefulness of the double-light telescopic catheter in the diagnosis of bacterial pneumonia in patients under mechanical ventilation]. / Utilidad del catéter telescópico de doble luz en el diagnóstico de la neumonía bacteriana en pacientes bajo ventilación mecánica.

Fifty-eight patients who presented clinical criteria of pneumonia (fever, leukocytosis, purulent tracheo-bronchial secretions, and lung infiltrate of recent appearance in X-ray) were prospectively studied in order to determine the cost effectiveness [correction of rentability] of quantitative culture of bronchial secretions by means of a telescopic catheter (TC) in the diagnosis of bacterial pneumonia in patients under mechanical ventilation. In 25 patients (43%) a positive culture was obtained above 10(3) UFC/ml, confirming the pneumonia diagnosis in 17 cases and detecting a false positive result in one patient. In no case with a count less than 10(3) UFC/ml pneumonia diagnosis could be confirmed, being this diagnosis excluded in 24 of 33 patients with a count lower than 10(3) UFC/ml. These results suggest that the presence of fever, purulent tracheobronchial secretions and lung infiltrate in an intubated patient under mechanical ventilation does not indicate the presence of pneumonia in a high percentage of cases and that CT scan can identify those patients who require antimicrobial treatment, and this avoiding its use in patients who do not need it, with the resulting decrease in morbidity and high cost.