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.
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.
Methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant coagulase-negative staphylococci (MRCoNS) are among the most frequent causes of hospital infections worldwide, thus justifying the increasing use of vancomycin. In this study, we evaluated the presence of glycopeptide-resistant staphylococci, in 41 patients hospitalized in the Clinical Hospital of the Federal University of Uberlândia in Uberlândia, MG, who were being treated with vancomycin. All isolates were plated on Mueller-Hinton agar containing vancomycin. Vancomycin resistance was confirmed by surface growth after incubation for 24-48 h at 35ºC. Heteroresistance was evaluated by plating with a large inoculum (10 8 CFU/mL). One patient with nephritis who was on a hemodialysis program was diagnosed with the phenotype isolate of vancomycinintermediate Staphylococcus aureus (VISA) (CIM = 8 μg/mL) and in eight patients, strains of heteroresistant Staphylococcus corresponding to the hVISA phenotype were isolated. In addition to the extended use of vancomycin, other risk factors associated with the presence of these microorganisms included the use of three or more antimicrobial agents, surgery, and three or more invasive procedures. Molecular analysis by randon amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) showed two clusters involving two samples each one of them, in surgical patients, with temporal and spatial relationship and isolates similarity concerning the susceptibility range to antimicrobial agents.
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