Farnesol increases the susceptibility of Burkholderia pseudomallei biofilm to antimicrobials used to treat melioidosis.

AIMS: The aim of this study was to analyse the in vitro activity of farnesol alone and combined with the antibacterial drugs amoxicillin, doxycycline, ceftazidime and sulfamethoxazole-trimethoprim against Burkholderia pseudomallei biofilms. METHODS AND RESULTS: Susceptibility was assessed by the broth microdilution test and cell viability was read with the oxidation-reduction indicator dye resazurin. The biofilms were evaluated through three microscopic techniques (optical, confocal and electronic microscopy). The minimum biofilm erradication concentration (MBEC) for farnesol was 75-2400 mmol l(-1). In addition, farnesol significantly reduced the MBEC values for ceftazidime, amoxicillin, doxycycline and sulfamethoxazole-trimethoprim by 256, 16, 4 and 4 times respectively (P < 0·05). Optical, confocal and electronic microscopic analyses of farnesol-treated B. pseudomallei biofilms demonstrated that this compound damages biofilm matrix, probably facilitating antimicrobial penetration in the biofilm structure. CONCLUSIONS: This study demonstrated the effectiveness of farnesol against B. pseudomallei biofilms and its potentiating effect on the activity of antibacterial drugs, in particular ceftazidime, amoxicillin, doxycycline and sulfamethoxazole-trimethoprim. SIGNIFICANCE AND IMPACT OF THE STUDY: The intrinsic antimicrobial resistance of B. pseudomallei is a serious challenge for the treatment of melioidosis. Thus, this paper reports the inhibitory potential of farnesol against B. pseudomallei biofilms, as well as highlights the favourable pharmacological interaction of farnesol with antibiotics tested, not only on cell viability, but also in the structural morphology of biofilms.

Cross-resistance to fluconazole induced by exposure to the agricultural azole tetraconazole: an environmental resistance school?

This study aimed to investigate the influence of tetraconazole and malathion, both used in agricultural activities, on resistance to fluconazole, itraconazole and voriconazole in Candida parapsilosis ATCC 22019. The susceptibility to tetraconazole, malathion, fluconazole, itraconazole and voriconazole, through broth microdilution. Then, 12 independent replicates, were separated and exposed to four treatment groups, each one containing three replicates: G1: tetraconazole; G2: malathion; G3: fluconazole (positive control); G4: negative control. Replicates from G1, G2 and G3, were exposed to weekly increasing concentrations of tetraconazole, malathion and fluconazole, respectively, ranging from MIC/2 to 32 × MIC, throughout 7 weeks. The exposure to tetraconazole, but not malathion, decreased susceptibility to clinical azoles, especially fluconazole. The tetraconazole-induced fluconazole resistance is partially mediated by the increased activity of ATP-dependent efflux pumps, considering the increase in antifungal susceptibility after the addition of the efflux pump inhibitor, promethazine, and the increase in rhodamine 6G efflux and CDR gene expression in the G1 replicates. Moreover, MDR expression was only detected in G1 and G3 replicates, suggesting that MDR pumps are also involved in tetraconazole-induced fluconazole resistance. It is noteworthy that tetraconazole and fluconazole-treated replicates behaved similarly, therefore, resistance to azoles of clinical use may be a consequence of using azoles in farming activities.

Emergence of azole-resistant Candida albicans in small ruminants.

Small ruminant production is a common agricultural activity worldwide. However, studies on the fungal microbiota of these animals are scarce. Therefore, this study aimed at isolating yeasts from goats and sheep and evaluating the antifungal susceptibility of the recovered Candida albicans. A total of 120 animals from farms in Ceará State, Brazil, were assessed in this study. The samples were collected from nasal, oral and rectal cavities with sterile swabs. Candida spp., Trichosporon spp. and Rhodotorula spp. were isolated from small ruminants. Resistance to three azole drugs was observed in C. albicans. In summary, Candida spp. were predominantly observed as part of the microbiota of the nasal, oral and rectal cavities of small ruminants, including azole-resistant strains of C. albicans.

Antifolates inhibit Cryptococcus biofilms and enhance susceptibility of planktonic cells to amphotericin B.

The Cryptococcus neoformans species complex contains the most important agents of fungal meningoencephalitis. Therapeutic choices are limited and issues related to toxicity and resistance to antifungals have been described. The present study evaluated the inhibitory effect of the antifolate combinations sulfamethoxazole-trimethoprim (SMX/TMP) and sulfadiazine-pyrimethamine (SDZ/PYR) against planktonic cells and biofilms of C. neoformans and C. gattii. The influence of the antifolate combinations on the amphotericin minimum inhibitory concentration (MIC) of planktonic cells was also investigated. In addition, the effect of these combinations on the cellular ergosterol content of planktonic cells was studied. Strains of C. neoformans (n = 15) and C. gattii (n = 15) obtained from environmental or clinical sources were evaluated by the broth microdilution method. SMX/TMP and SDZ/PYR showed antifungal activity against free living cells and sessile cells of Cryptococcus spp. Moreover, planktonic cells showed increased susceptibility to amphotericin B after pre-incubation with sub-inhibitory concentrations of SMX/TMP or SDZ/PYR. The drug combinations SMX/TMP and SDZ/PYR were able to prevent the biofilm formation and showed inhibitory effect against mature biofilms of both species. Additionally, the study showed that antifolate drugs reduced the ergosterol content in C. neoformans and C. gattii planktonic cells. Our results highlight the antifungal potential of antifolate drugs.

Sesquiterpene farnesol contributes to increased susceptibility to ß-lactams in strains of Burkholderia pseudomallei.

This study aimed to evaluate the in vitro combination of farnesol and ß-lactams against Burkholderia pseudomallei. A total of 12 ß-lactamase-positive strains were tested according to CLSI standards. All strains were inhibited by farnesol, with MICs ranging from 75 to 150 µM. The combination of this compound with ß-lactams resulted in statistically significant ß-lactam MIC reduction (P ≤ 0.05). This study provides new perspectives for the use of farnesol combined with ß-lactam antibiotics against strains of B. pseudomallei.

Respiratory sleep disturbance in children and adolescents with cystic fibrosis.

UNLABELLED: Sleep disturbance has been described in cystic fibrosis (CF) patients as relevant to clinical and lung function predictive factors helping to improve the diagnosis and early intervention. Related paediatric studies are scarce. OBJECTIVE: To describe respiratory sleep disturbance (RSD) and its association with spirometric indices in a population of CF children. A second aim was to determine if spirometric indices and wake-time SpO2 are predictors of sleep disturbance. METHODS: A cross-sectional study involving 33CF paediatric patients. All participants underwent in-lab polysomnography (PSG), pulse oximetry and spirometry. A standardized sleep questionnaire was completed for each patient. Two subgroups were considered: I - Normal (FEV1>-1.64 z-score); II - Obstructed (FEV1≤-1.64 z-score). RESULTS: Participant's median age was 12 (6-18) years, 16 (48.5%) were male. Twenty-nine patients (87.9%) presented sleep complaints. Sleep efficiency was reduced; sleep latency and waking after sleep onset (WASO) increased. N1 increased, N2, N3, REM and awakenings were normal. The apnoea-hypopnoea index was 0.6/h (sd 0.9); respiratory disturbance index (RDI) was 6.6/h (sd 5.2). Mean awaking (97% (sd 1.1)) and sleep SpO2 (95% (sd 2.7)) were normal; mean nocturnal oximetry desaturation index was 2.36/h; minimal nocturnal SpO2 was 89% (sd 4.1). We found associations between mean nocturnal SPO2 and mean values of FEV1 (r=0.528; p=0.002) and FEF25-75 (r=0.426; p=0.013). There were significant differences in nocturnal SpO2 between normal and obstructed patients (p<0.000). PSG data correlated with the questionnaire answers for night awakenings and WASO (p=0.985) and difficult breathing during sleep and RDI (p=0.722). This study points to most CF children having sleep complaints, and highlights the correlation between subjective assessment of sleep and PSG and spirometric results. Awake-time SpO2 and spirometric values are possible risk predictors for nocturnal desaturation.

[A case of Legionella pneumophila pneumonia]. / Um caso de pneumonia por Legionella pneumophila.

Legionella pneumophila is an uncommon cause of pneumonia, mainly in children. We present a case with aggressive disease and unfavourable outcome. The diagnosis was established by serum antibody detection and immunofluorescence and culture of a fragment of lung tissue obtained at necropsy. We focus the importance of this aetiology in nosocomial pneumonia and community-acquired pneumonia with an atypical evolution. The need for specific therapy and some preventive measures are also stressed.

Non-invasive ventilation in complex obstructive sleep apnea--a 15-year experience of a pediatric tertiary center.

INTRODUCTION: Obstructive sleep apnea (OSA) affects approximately 1-3% of pediatric population and is associated with significant morbidity. As adenotonsillar hypertrophy (ATH) is its primary cause in children, elective adenotonsillectomy is the first treatment of choice. Noninvasive ventilation (NIV) has been increasingly considered as an option, mainly for children with complex diseases, ineligible or waiting for surgeries, or after surgery failure. OBJECTIVES: To describe the experience in the management of children with complex OSA, and to evidence the feasibility and advantages of NIV. METHODS: This was a retrospective cohort study of 68 children on NIV, in whom complex OSA was the main indication for ventilation, in a Pediatric Respiratory Unit at a University Hospital between January 1997 and March 2012. Demographic and clinical data were collected on the underlying diagnosis, therapeutic interventions prior to NIV, NIV related issues and outcome. RESULTS: Forty (59%) children were male, median age at starting NIV was 6 years and 7 months, with interquartile range (IQR) of 15-171 months. Twenty-two (32%) were infants and 25 (37%) adolescents. The most common diagnosis was congenital malformations and genetic disorders in 34 (50%) patients. Nine patients had cerebral palsy, 8 were post treatment for central nervous system tumors and 6 had inborn errors of metabolism. Three children had ATH and three obesity. The majority of patients (76%) had exclusively obstructive OSA and started CPAP. Ten patients had minor complications. Twenty-two patients stopped NIV due to clinical improvement, 8 were non-compliant and 8 patients died. NIV median duration was 21.5 months (IQR: 7-72). CONCLUSIONS: NIV is feasible and well tolerated by children with OSA associated with complex disorders, and has been shown to have few complications even in infants and toddlers.

Environmental tobacco smoke (ETS) exposure and respiratory morbidity in school age children.

INTRODUCTION: Tobacco smoke is a risk factor for Chronic Obstructive Pulmonary Disease and a major public health problem. Prenatal maternal smoking and post-natal environmental tobacco smoke (ETS) lead to dose-dependent decrease in lung function and respiratory morbidity. Influence of different socioeconomic indicators and ETS in the home has also been suggested. METHODS: Data on 313 children (52 % male) from 4 public schools in Lisbon was analyzed [1st (46 %) and 4th graders]. ETS assessment and respiratory symptoms were based on a self-answered questionnaire. All children performed standard spirometry in the school setting and 54 % were acceptable according to ATS/ERS criteria. Descriptive and bivariate analysis of the most relevant variables was done, followed by multiple logistic regression analysis adjusted to the variables with clinical/statistical relevance. RESULTS: ETS in the home was found in 41 % (maternal smoking during pregnancy 18 %, smoking mother 32 %, smoking father 38 %). Smoking fathers had lower education and less qualified occupation. Cough was more frequent in children with a smoking mother (adjusted OR = 2.1 95CI 1.1-4.0) and wheezing in children with maternal smoking during pregnancy and smoking parents. All differences were significant (p < 0.05). No association was found between parental education and cough/wheeze or ETS and respiratory infections/asthma/decreased spirometric values. CONCLUSIONS: Children in Lisbon are frequently exposed to ETS which results in significant respiratory morbidity. Targeted interventions must have social conditions in consideration. In this study, field spirometry was not helpful in early detection of lung function disability in children associated with ETS.

Mycotic aneurysm caused by Burkholderia pseudomallei: report of a Brazilian strain genetically related to Thai strains.

Melioidosis, a severe infectious disease caused by Burkholderia pseudomallei that is prevalent in Southeast Asia and Northern Australia, has been sporadically reported in Brazil since 2003. We report a case of aortic aneurysm with blood culture positive for B. pseudomallei. The phylogenetic analysis of 16S ribosomal DNA showed this isolate to be evolutionarily grouped with the MSHR346 strains from Thailand.