Carriage of gram-negative bacilli in young Brazilian children with community-acquired pneumonia.

BACKGROUND: Gram-negative bacilli are not infrequently encountered as etiologic organisms of pneumonia in children in warm-climate countries. OBJECTIVES: To investigate the nasopharyngeal carriage rate and antimicrobial susceptibility patterns of gram-negative bacilli colonizing children with community-acquired pneumonia in Fortaleza, Brazil. METHODS: A single nasopharyngeal specimen was collected from children 2 months to 5 years of age presenting at one of the three children's hospitals in Fortaleza and fulfilling the World Health Organization criteria for pneumonia. Randomly recruited healthy children from public daycare centers and immunization clinics served as controls. RESULTS: The study included 912 children, 482 (53%) with pneumonia and 430 (47%) controls. Aerobic gram-negative bacilli were seen in 79 (16%) of the 482 children with pneumonia and 51 (12%) of the 430 healthy controls. Nonfermentative gram-negative bacilli were seen in 85 (18%) of children with pneumonia and 54 (13%) of healthy controls. Neither gender, nutritional status, season, previous hospital admission nor antibiotic use was associated with carriage with gram-negative bacilli. However, pneumonia was associated with increased carriage, whereas concomitant colonization with Streptococcus pneumoniae or Haemophilus influenzae was associated with decreased carriage with gram-negative bacilli. Only 36% of all Escherichia species and 76% of all Klebsiella isolates were susceptible to cotrimoxazole; 90% of all Acinetobacter species were susceptible to gentamicin. CONCLUSION: Nasopharyngeal carriage with gram-negative bacilli, in particular with Acinetobacter species, is common and associated with a clinical diagnosis of community-acquired pneumonia in children in Fortaleza, Brazil.

Emerging importance of multidrug-resistant Acinetobacter species and Stenotrophomonas maltophilia as pathogens in seriously ill patients: geographic patterns, epidemiological features, and trends in the SENTRY Antimicrobial Surveillance Program (1997-1999).

As part of the SENTRY Antimicrobial Surveillance Program, a total of 1078 Acinetobacter species and 842 Stenotrophomonas maltophilia isolates were collected between January 1997 and December 1999 from 5 geographic regions (Canada, the United States, Latin America, Europe, and the Asia-Pacific). The frequency of infections (by geographic region and body site), including those due to imipenem-resistant Acinetobacter species and trimethoprim-sulfamethoxazole (TMP-SMZ)-resistant S. maltophilia, was evaluated. The possibility of seasonal variations in bloodstream infections caused by Acinetobacter species was studied, as was the activity of several therapeutic antimicrobials against all strains. Acinetobacter species and S. maltophilia were most frequently associated with pulmonary infections, independent of the region evaluated. In contrast, patterns of antimicrobial resistance markedly varied among distinct geographic regions, especially for nosocomial isolates. Although the carbapenems were the most active antimicrobials against Acinetobacter species, nearly 11.0% of the nosocomial isolates were resistant to this drug group in both regions. TMP-SMZ, ticarcillin-clavulanic acid, gatifloxacin, and trovafloxacin were the only agents with consistent therapeutic activity against S. maltophilia isolates. Rates of resistance to TMP-SMZ ranged from 2% in Canada and Latin America to 10% in Europe. The geographic differences in resistance patterns among Acinetobacter species and S. maltophilia isolates observed in this study emphasize the importance of local surveillance in determining the most adequate therapy for acinetobacter and S. maltophilia infections and the possible clonal, epidemic nature of occurrence.

Genetic diversity among strains of Moraxella catarrhalis cultured from the nasopharynx of young and healthy Brazilian, Angolan and Dutch children.

The present study describes the carriage patterns and genetic variability of Moraxella catarrhalis strains isolated from children living in different countries. Moraxella catarrhalis is genetically heterogeneous, but little is known about its geographic distribution and phenotypic and genetic diversity in warm-climate countries. A collection of 99 isolates from 30 Brazilian, 19 Angolan and 50 Dutch healthy children, all less than 5 years of age, was investigated for phenotypic and genotypic relatedness. The isolates from the three countries were similar where biochemical reactivity was concerned: 89 strains were beta-lactamase-producing and 87 were complement-resistant as determined by phenotype. There was no geographical difference in the prevalence of beta-lactamase-producing isolates, but the carriage rate of complement-resistant strains was significantly higher in Dutch than in Angolan children (P=0.004). Complement resistance of 66 randomly selected strains was genetically confirmed in a Southern hybridization assay by a novel DNA probe that is specific for complement-resistant strains and that demonstrated a sensitivity of 97% and a specificity of 100%. PCR amplification based on the probe sequence had a sensitivity of 98% and a specificity of 57% when compared to the outcome of a conventional culture spot test. PCR restriction fragment length polymorphism analysis of the MU 46 locus and pulsed-field gel electrophoresis of SpeI DNA macrorestriction fragments revealed genetic heterogeneity of strains from within and between the three countries, and no geographical clustering could be established. In conclusion, similar phenotypic characteristics but genotypic heterogeneity was found among Moraxella catarrhalis strains colonizing children in three different continents.

Molecular epidemiology of penicillin-resistant Streptococcus pneumoniae colonizing children with community-acquired pneumonia and children attending day-care centres in Fortaleza, Brazil.

To study clonal diversity of penicillin-resistant Streptococcus pneumoniae, 161 randomly selected isolates with reduced susceptibility to penicillin, collected from the nasopharynx of children under 5 years of age with community-acquired pneumonia and healthy controls from public day-care and immunization centres in Fortaleza, Brazil, were characterized by microbiological and serological techniques and automated ribotyping. Also included were 44 randomly selected penicillin-susceptible strains and three international reference strains. With automated ribotyping 75 ribopatterns were observed: 50 ribogroups were unique and 25 ribogroups were represented by two or more isolates. Genetic diversity was extensive but some degree of genetic homogeneity was found in strains from children with pneumonia, strains from children in day-care centres, isolates with reduced susceptibility to penicillin and isolates expressing 'paediatric' serogroups. Fourteen (56%) clusters contained both isolates with reduced penicillin susceptibility and penicillin-susceptible isolates, suggesting emergence of penicillin resistance. In general, there was a good correlation between ribogroups and serogroups, but 12 (48%) clusters contained isolates with alternative serogroups. Isolates with such alternative serogroups were more often encountered in penicillin-susceptible strains (41%) than in strains with reduced susceptibility to penicillin (7%). Thirty-eight (19%) isolates (including seven penicillin-susceptible strains) showed ribotypes indistinguishable from those of two international epidemic clones of S. pneumoniae: ribogroup 54-S-1 (15 isolates) with a ribopattern characteristic of the 23F multiresistant 'Spanish/USA' clone and ribogroup 74-S-3 (23 isolates) with a pattern similar to that of the 6B multiresistant 'Spanish' clone.

Striking differences in the nasopharyngeal flora of healthy Angolan, Brazilian and Dutch children less than 5 years old.

Community-acquired pneumonia from enteric gram-negative bacilli is more common in developing than in industrialized countries. We investigated the nasopharyngeal flora in healthy children from Angola, Brazil and The Netherlands to see whether enteric gram-negative bacilli are more often part of the commensal flora in developing countries. Nasopharyngeal specimens were collected from children aged between 4 months and 5 years in day-care centres and immunization clinics. Children who had received antibiotics or were malnourished were excluded. Brazilian and Angolan children had a higher number of household members than Dutch children (5.5 and 7 vs 3.9 mean number of household members, respectively) (p < 0.0001). Enteric and non-fermentative gram-negative bacilli were much more prevalent in Brazilian (50%) and Angolan (57%) children than in Dutch (4%) children (p < 0.0001). By univariate analysis, carriage of enteric gram-negative bacilli was associated with the number of household members (r = 0.26; p < 0.001). The high carriage rate of enteric gram-negative bacilli in children from Angola and Brazil may explain why enteric gram-negative bacilli are a common cause of pneumonia in developing countries.