Tracheostomized children tracheal colonization and antibiotic resistance profile - A STROBE analysis.

AIMS: To verify the prevalence of Potentially pathogenic bacteria (PPB) and their antimicrobial resistance profile in tracheal aspirates of children with tracheostomy and compare it to clinical data. METHODS: A cross-sectional study was conducted in patients aged 0-18 years who all underwent tracheostomy cannula change (TCC) performed by the Otolaryngology Unit at Hospital de Clínicas de Porto Alegre, Brazil, between October, 2017 and December, 2018. Patients were submitted, at the time of TCC, to a tracheal aspirate through the tracheostomy and secretion was sent to microbiological analysis and antimicrobial susceptibility testing. Clinical data were evaluated through available patients' electronic medical records. RESULTS: Forty-four patients had their tracheostomy aspirate cultured and all but one presented PPB growth (97.7%). Median age was 3 years-old. Pseudomonas aeruginosa was the most prevalent bacteria (56.9%) and it was resistant to gentamycin, amikacin and cefepime in 36%, 28% and 12% of the culture tests, respectively. P. aeruginosa resistance to gentamycin and to cefepime suggested an association with the number of antibiotic classes used in the 12 months before enrollment (both p=0.04) and with 2 or more hospital admissions in the same period (p=0.03 and p=0.02, respectively). Staphylococcus aureus was isolated in 9.1% and there was no MRSA. CONCLUSION: It was found a 97.7% prevalence of PPB in the cultured aspirates; the most prevalent bacterium was P. aeruginosa and there was no MRSA identification. Data suggest an association between P. aeruginosa antimicrobial resistance with previous use of antibiotic therapy.

Incidence of post-intubation subglottic stenosis in children: prospective study.

OBJECTIVE: To evaluate the incidence of subglottic stenosis in children undergoing endotracheal intubation. METHODS: Children in the paediatric intensive care unit of a tertiary care hospital were considered eligible for inclusion if they received endotracheal intubation for more than 24 hours. After extubation, children underwent flexible fibre-optic nasolaryngoscopy. Based on this first evaluation, they were divided into two groups: 'acute normal', with mild laryngeal alterations or normal findings; and 'acute alterations', with moderate to severe laryngeal alterations. Further laryngoscopic follow up (7-10 days later) was undertaken for those children in the acute normal group who developed symptoms during follow up (after discharge from the intensive care unit), and for all children in the acute alterations group. Children were then classified into two final groups: 'normal final examination', with no chronic changes; and 'subglottic stenosis'. RESULTS: We included 123 children. The incidence of subglottic stenosis was 11.38 per cent (95 per cent confidence interval, 6.63-17.94 per cent). All the children who developed subglottic stenosis had had moderate to severe alterations immediately after extubation. CONCLUSION: This incidence of subglottic stenosis is quite high and needs further investigation to identify risk factors.

Ventilatory muscle strength in cystic fibrosis patients: a literature review.

UNLABELLED: The ventilatory mechanic changes that occur in cystic fibrosis (CF) patients may lead to alterations in the respiratory muscle strength levels. However, the findings regarding the strength profile in these patients are still contradictory. OBJECTIVE: To evaluate, trough a literature review, the respiratory muscle strength behavior in CF patients. We have performed a search in Medline/Pubmed, Scielo, IBECS and LILACS databases selecting observational cross-sectional, prospective or retrospective studies, as well as randomized clinical trials, published between 1981 and 2011, using the following terms: cystic fibrosis, respiratory muscle strength, inspiratory maximal pressure and muscle training. The majority of the studies 71.24% have shown normal or above normal respiratory muscle strength, whilst 28.57% demonstrated reduced or near-normal values. Most of these findings were attributed to an increased work of breathing as a result of airway obstruction and chronic persistent cough. Taken together, the analyses of selected studies have showed conflicting findings regarding respiratory muscle strength behavior in these patients. However, most of the studies seem to indicate that CF patients presented maximum respiratory pressures normal or above predicted values.

Geographic heterogeneity of 4 common worldwide cystic fibrosis non-DF508 mutations in Brazil.

Cystic fibrosis (CF) is an autosomal recessive disease caused by at least 750 different mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. The frequency of the most common mutation (DF508) in Brazilian patients of European origin is 47%. To determine the frequency of 4 other common CF mutations (G542X, G551D, R553X, and N1303K) in Brazilian patients of European origin, we used direct polymerase chain reaction (PCR) amplification of DNA obtained from dried blood spots on Guthrie cards. The DNA came from 247 non-DF508 chromosomes from 172 Brazilian CF patients ascertained from 5 different states of Brazil. The results show that the 4 mutations account for 17% of the non-DF508 alleles and only 9% of the total number of Brazilian CF alleles. Overall, the frequency of each mutation is different from northern European and North American populations but similar to southern European populations, mainly the Italian and Spanish populations. When Brazilian patients of European origin are grouped according to state of birth, the frequencies of the mutations are significantly different between southern and southeastern states of Brazil. Therefore there are serious implication for risk assessment of DNA-based tests in heterogeneous populations such as Brazilians. Further studies are needed to identify the remaining 44% of CF mutations for the different populations and regions of Brazil.

Analysis of the delta F508 mutation in a Brazilian cystic fibrosis population: comparison of pulmonary status of homozygotes with other patients.

Sixty-one cystic fibrosis patients admitted for check-up or antibiotic treatment were enrolled for genetic and clinical evaluation. Genetic analysis was performed on blood samples stored on neonatal screening cards using PCR techniques to determine the presence of delta F508 mutations. Clinical evaluation included Shwachman and Chrispin-Norman scores, age at onset of symptoms and diagnosis, spirometry, awake and sleep pulse oximetry, hyponychial angle measurement and presence of chronic Pseudomonas aeruginosa colonization. Eighteen patients (29.5%) were homozygous for the delta F508 mutation, 26 (42.6%) had one delta F508 mutation and 17 (27.9%) were noncarriers, corresponding to a 50.8% prevalence of the mutation in the whole population. Analysis by the Kruskal-Wallis test for comparison of genetic status with continuous variables or by the chi-square test and logistic regression for dichotomous variables showed no significant differences between any two groups for alpha = 0.05. We conclude that genetic status in relation to the delta F508 mutation is not associated with pulmonary status as evaluated by the above variables.

Analysis of the F508 mutation in a Brazilian cystic fibrosis population: comparison of pulmonary status of homozygotes with other patients

Sixty-one cystic fibrosis patients admitted for check-up or antibiotic tretment were enrolled for genetic and clinical evaluation. Genetic analysis was performed on blood samples stored on neonatal screening cards using PCR techniques to determine the presence of deltaF508 mutations. Clinical evaluation included Shwachman and Chrispin-Norman scores, age at onset of symptoms and diagnosis, spirometry, awake and sleep pulse oximetry, hyponychial angle measurement and presence of chronic Pseudomonas aeruginosa colonization. Eighteen patients (29.5 percent) were homozygous for the deltaF508 mutation, 26 (42.6 percent) had one deltaF508 mutation and 17 (27.9 percent) were noncarriers, corresponding to a 50.8 percent prevalence of the mutation in the whole population. Analysis by the Kruskal-Wallis test for comparison of genetic status with continuous variables or by the chi-square test and logistic regression for dichotomous variables showed no significant differences between any two groups for alpha=0.05. We conclude that genetic status in relation to the deltaF508 mutation is not associated with pulomnary status as evaluated by the above variables.

Cystic fibrosis in the Brazilian population: DF508 mutation and KM-19/XV-2C haplotype distribution.

We have used PCR amplification of DNA obtained from Guthrie cards to identify the DF508 mutation and correlate it with the allele frequencies at two polymorphic loci (XV-2C and KM-19) closely linked to the cystic fibrosis gene. The DNA came from 193 white Brazilian families affected by cystic fibrosis and living in five different states of Brazil. The distribution of the haplotypes derived from the DF508 and non-DF508 XV-2C/KM-19 genotypes indicates that 88% of the DF508 alleles are linked to haplotype B and suggests that high heterogeneity exists among the non-DF508 cystic fibrosis alleles occurring in different states. Our data can be used to compare linkage disequilibrium between Brazilians and other heterogeneous populations where the DF508 mutation frequency is low and where many different rare mutations account for the remaining recessive cystic fibrosis alleles.

Regional distribution of cystic fibrosis-linked DNA haplotypes in Brazil: multicenter study.

The restriction fragment length polymorphism (RFLP) haplotypes of cystic fibrosis (CF) alleles vary between populations. To determine the distribution of two RFLPs (XV-2C and KM-19) that are tightly linked to the CF locus, we analyzed a white sample from five different states of Brazil. The haplotypes of 314 CF- and 237 non-CF-bearing chromosomes were uniformly distributed over the five states. The XV-2C allele and haplotype frequencies and the degree of linkage disequilibrium were determined. These were similar to values previously reported in southern European countries but different from results reported for northern and central Europe and North America. In contrast, although KM-19 allele frequencies differed between Brazilian states and European and North American countries, these frequencies were similar to values reported in black Americans. A significant proportion of Brazilian CF-bearing chromosomes had less common haplotypes, suggesting a heterogeneous distribution of CF gene mutations among Brazilians. Further studies are needed to identify the mutations affecting the Brazilian CF patients with various haplotypes.

DNA analysis of cystic fibrosis in Brazil by direct PCR amplification from Guthrie cards.

A 3 bp deletion of codon 508 (phenylalanine) of the cystic fibrosis (CF) gene constitutes the mutation of most CF chromosomes. The frequency of this mutation (referred to as delta F508), varies considerably between populations, ranging from 26% of the CF mutations in Turkey to 88% in Denmark. To determine the frequency of the delta F508 mutation in Brazilian Caucasoid CF patients, we used direct polymerase chain reaction (PCR) amplification of DNA obtained from dried blood spots on Guthrie cards, followed by ethidium bromide staining of gels. Although the overall frequency of the delta F508 mutation was 47% of 380 CF chromosomes from Brazilian Caucasoids born in five different states, significant interstate differences were observed, ranging from a delta F508 frequency of 27% to 53%. While our method could be used to screen patients and their relatives for carrier testing and prenatal diagnosis, the efficacy of screening only for the delta F508 mutation would be low, and would vary from state to state. Screening for a panel of local mutations will be needed to increase the mutation detection rate and optimize genetic counseling.