Evaluation of silver nanoparticle-impregnated PMMA loaded with vancomycin or gentamicin against bacterial biofilm formation.

INTRODUCTION: Bone cement containing vancomycin or gentamicin is a therapeutic strategy for combating orthopedic infections: however, the activity of these antibiotics is narrow. Silver nanoparticles (AgNPs) are nanocomponents with a wide spectrum, including multidrug-resistant bacteria. In the present study, we aimed to evaluate the effect of AgNP-loaded polymethylmethacrylate (PMMA) on biofilm formation by Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus epidermidis. METHODS: The effect of AgNP-loaded PMMA with and without vancomycin or gentamicin on biofilm production was quantitatively analyzed. S. aureus, E. coli, P. aeruginosa, and S. epidermidis were included as biofilm-producing microorganisms in the in vitro model. RESULTS: AgNP-loaded PMMA with antibiotics reduced the number of colony-forming units (CFUs; p<0.001). However, AgNP-loaded PMMA alone did not significantly reduce biofilm formation. CONCLUSION: Our study demonstrated the potential of AgNP-loaded PMMA. Notably, we observed that AgNP-loaded PMMA containing vancomycin or gentamycin exhibited significantly superior efficacy, with satisfactory activity against most biofilm-forming microbial agents examined.

Oral doxycycline to carbapenem-resistant Acinetobacter baumannii infection as a polymyxin-sparing strategy: results from a retrospective cohort.

Acinetobacter baumannii infection presents a high mortality rate and few therapeutic options. This study aimed to evaluate clinical-microbiological characteristics and prognosis factors of patients diagnosed with A. baumanni. infections treated with oral doxycycline. A retrospective cohort of hospitalized patients with confirmed Acinetobacter spp. infection between 2018 and 2020 receives at least 3 days of oral doxycycline. Clinical and microbiological data were evaluated, including the outcome and molecular characterization of A. baumannii. Doxycycline minimal inhibitory concentrations were evaluated by the broth dilution method. One hundred patients were included with a median age of 51 years. The leading site of infection was pulmonary (n = 62), followed by the soft tissues and skin (n = 28). A. baumannii resistant to carbapenem was found on 94%. The gene blaOXA-23 and blaOXA-51 were amplified in all recovered isolates of A. baumannii (n = 44). Doxycycline MIC50 and MIC90 were 1 µg/mL and 2 µg/mL, respectively. Death rate at 14 days and 28 days of follow-up was 9% and 14%, respectively. The prognostic factors related to death at end of follow-up were age > 49 years [85.7% vs. 46%, CI 95% 6.9 (1.4-32.6), P = 0.015] and hemodialysis [28.6% vs. 7%, CI 95% 5.33 (1.2-22.1), P = 0.021]. Patients treated with doxycycline to A. baumannii presented a relatively low death rate, and risk factors related to death were age and hemodialysis. Further and larger studies should compare polymyxin to doxycycline to better understand the differences between these therapeutic options.

A carbapenem-resistant Acinetobacter baumannii outbreak associated with a polymyxin shortage during the COVID pandemic: an in vitro and biofilm analysis of synergy between meropenem, gentamicin and sulbactam.

BACKGROUND: During the COVID-19 pandemic, the burden of nosocomial infections caused by MDR pathogens has caused a shortage of polymyxins. Thus, we evaluated the in vitro synergism and antibiofilm activity of antimicrobial combinations and propose a test kit for synergism against carbapenem-resistant Acinetobacter baumannii (CRAB). METHODS: Fifty-six CRAB isolates were tested for synergy between meropenem, gentamicin and ampicillin/sulbactam. MICs were determined by broth microdilution. Synergism was tested using chequerboard analysis, followed by a time-kill curve. Additionally, minimum biofilm eradication concentration was determined and the antibiofilm activity of the combinations was evaluated by MTT assay and biomass reduction. A test kit was developed for routine laboratory testing to detect synergism. RESULTS: All CRAB isolates were resistant to gentamicin and ampicillin/sulbactam. Chequerboard synergism occurred against 75% of the isolates. Meropenem + ampicillin/sulbactam was the most frequent combination with synergism (69%), followed by ampicillin/sulbactam + gentamicin (64%) and meropenem + gentamicin (51%). All combinations presented only bacteriostatic activity and no bactericidal or antibiofilm effects. The routine laboratory test showed 100% accuracy compared with other in vitro assays. CONCLUSIONS: Our study demonstrates the potential role of antibiotic combinations against planktonic bacteria. In vitro synergism is possible and can be an alternative treatment for patients with CRAB infection during a polymyxin shortage.

Evaluation of Staphylococcus aureus and Candida albicans biofilms adherence to PEEK and titanium-alloy prosthetic spine devices.

BACKGROUND: Titanium and polyether-ether-ketone (PEEK) interbody cages are commonly used for spine fusion. Few data are known about bacterial and yeast biofilms formation in these implants. The aim of this study was to compare Staphylococcus aureus and Candida albicans biofilm formation in the surface of two different interbody devices used routinely in spine surgery. METHODS: Six bodies of proof specimens of PEEK and titanium alloy were used for microbiological tests, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. Experimental biofilm was produced with Staphylococcus aureus and Candida albicans, followed by quantitative analysis of planktonic cells and sessile cells. The comparison between the medians of biofilm quantification between the two models was performed using the Mann-Whitney test and considered the statistical difference for a p < 0.05. RESULTS: In the S. aureus model, in both planktonic and sessile cell counts, titanium-alloy samples showed lower values for colony forming units per milliliter (UFC/mL) (p < 0.05). The evaluation through the optic density of planktonic and sessile cells showed lower values in the titanium-alloy samples, however, only statistically significant in planktonic cell count (p < 0.05). The count of planktonic yeast cells in PEEK was similar to titanium-alloy samples, while the count of sessile yeast cells in titanium alloy was lower when compared to PEEK (p < 0.05). CONCLUSION: Titanium-alloy models were associated with less staphylococcal and Candida biofilm formation when compared with PEEK.

Discovering the Giant Nest Architecture of Grass-Cutting Ants, Atta capiguara (Hymenoptera, Formicidae).

Atta capiguara is a grass-cutting ant species frequently found in Cerrado biome. However, little is known about the giant nest architecture of this ant. In this study, we investigated the architecture of three A. capiguara nests from a fragment of Cerrado in Botucatu, São Paulo, Brazil. Casts were made of the nests by filling them with cement to permit better visualization of internal structures such as chambers and tunnels. After excavation, the depth and dimensions (length, width, and height) of the chambers were measured. The results showed the shape of Atta capiguara nests consisting of mounds of loose soil with unique features resembling a conic section. The fungus chambers were found distant from the mound of loose soil and were spaced apart and distributed laterally at the soil profile. The waste chambers were located beneath the largest mound of loose soil. Both the fungus and waste chambers were separated and distant. Our study contributes to a better understanding of the so far unknown nest architecture of the grass-cutting ant A. capiguara.

Sturge-Weber syndrome in an orthodontic patient.

The aim of this article was to describe the Sturge-Weber syndrome in a patient with orthodontic requirements. Pathologies involved in this syndrome affect facial cranial growth.

[Intestinal perforation in consequence of small intestine's diverticulitis]. / Perfuração de intestino delgado por doença diverticular jejunal.

Small Intestine's diverticulosis is an uncommon pathology of intestine. It's more evident at jejune and can be complicated by intestinal perforation, obstruction or diverticulitis, increasing the mortality. We describe a forty years old female patient that arrived at emergency service complained of diffuse abdominal pain. There aren't signals of peritonitis and the radiological evaluation showed small intestine's distension. Surgical intervention was performed revealing multiples diverticulums at jejune and intestinal perforation. The aim of this article is present a case of Small Intestine's diverticulosis and its complications that had precise intervention resulting in a favorable resolution.

Characteristics of smoking among physicians in the Federal District of Brazil.

OBJECTIVE: To profile the characteristics of smoking among physicians working in the Federal District of Brazil. METHODS: A questionnaire on smoking, adapted from that used by the World Health Organization, was mailed to all physicians registered with the Federal District Regional Council of Medicine. Of the 7023 questionnaires mailed, 830 (12%) were duly completed and returned. RESULTS: Among the physicians participating in the study, the prevalence of smoking was 7.2% (5.9% being regular smokers and 1.3% being occasional smokers). The remainder of the sample consisted of nonsmokers (70.1%) and former smokers (22.7%). In terms of gender, approximately 8.5% of the male physicians were smokers, compared with 5.3% of the female physicians (p > 0.05). Of the physicians who smoked, 80% had taken up the habit before the age of 20, 13% from 21 to 30, and 7% after the age of 31. The prevalence of smoking by specialty was as follows: Surgeons, 10.3%; Anesthesiologists, 10.3%; Clinicians, 9.1%; Gynecologists, 2.9%; and Pediatricians, 2.4%. Approximately 75% of the smoking physicians had been advised by their own doctors to stop smoking, although only 34.9% had tried to quit smoking with the preceding year. Of the physicians responding, 57.1% agreed that smoking is a health hazard, and 26.3% reported smoking in hospitals or doctors offices. CONCLUSION: Efforts to control smoking in the Federal District should be intensified and, despite the fact that the prevalence of smoking is declining among physicians, smoking cessation programs should target this population.

Analysis of pulmonary mechanics in an experimental model of sepsis.

OBJECTIVE: To determine whether pulmonary mechanics are altered in mice with sepsis. METHODS: A total of 40 Balb/c mice were divided into two groups: survival (n = 21) and pulmonary mechanics (n = 19). The survival group was divided into three subgroups: control (n = 7), sublethal (n = 7) and lethal (n = 7). The pulmonary mechanics group was also divided into three subgroups: control (n = 5), sublethal (n = 7) and lethal (n = 7). Sepsis was induced through cecal ligation and puncture, the latter varying in degree (sublethal or lethal). At eight hours after the intervention, pulmonary mechanics were measured through end-inflation occlusion. In the pulmonary mechanics group, the following variables were studied: total pressure, resistance, viscoelasticity, dynamic compliance and static compliance. The data obtained were analyzed using one-way ANOVA. RESULTS: The data for the survival group indicate the efficacy of the model employed. There were no statistically significant differences among the pulmonary mechanics subgroups in terms of dynamic compliance, static compliance, total pressure, resistance or viscoelasticity. CONCLUSION: At eight hours after cecal ligation and puncture, there were no changes in the lung parenchyma, nor were any alterations observed in the viscous and viscoelastic components of the lung.

Prevalence and characteristics of smoking among youth attending the University of Brasília in Brazil.

OBJECTIVE: To determine the prevalence of smoking and to describe the profile and smoking habits of students attending the Universidade de Brasília (University of Brasília) in Brasília, Brazil. METHODS: A total of 1341 students responded to a smoking questionnaire, adapted from the World Health Organization questionnaire, including questions directed at smokers, former smokers and nonsmokers. Twenty different courses in the areas of health, exact sciences and human sciences were evaluated. The students included in the study were duly enrolled in day courses and were evaluated during the second semester of 2003. RESULTS: The overall prevalence of smoking was 14.7%. Approximately 80.8% of the students were nonsmokers, and 4.5% were former smokers. In the study sample, 57.3% of the students were male. No significant difference (p > 0.05) in the prevalence of smoking was observed in terms of gender or class year. The mean age of the study population was 21.6 +/- 3.6 years, and the mean age at which the smoking habit was acquired was 17 +/- 2.8 years. The percentage of smokers was higher in the Geology, Communication, and History courses (32.9, 26.3 and 24.4%, respectively). Mean consumption was 7.5 cigarettes per day. The majority (72.6%) of the students used commercial cigarettes rather than other types of tobacco. CONCLUSION: The high prevalence of smoking observed in the present study is similar to that reported for other universities and indicates the need for smoking control policies in university environments.