Assessing the Hawthorne effect on hand hygiene compliance in an intensive care unit.

BACKGROUND: The influence of the Hawthorne effect on hand hygiene compliance in an intensive care unit was assessed using covert and overt direct observation. METHODS: The observational study was conducted from February to November 2018 in a 24-bed adult intensive care unit in a 243-bed tertiary care hospital, in four periods (P): P-1, February 5-March 3, 29 h (covert) and P-2, March 15-April 16, 33 h (overt), prior to an educational campaign on hand hygiene; and P-3, August 27-September 28, 33 h (covert) and P-4, October 3-November 6, 35 h (overt), after the campaign. Three 20-min observation sessions were performed daily, randomly distributed in the morning, afternoon and evening shifts, including holidays and weekends. Hand hygiene compliance rates observed in Periods 2 and 4 were displayed on an electronic panel installed in the unit. Hand hygiene compliance was assessed according to the World Health Organization "My Five Moments for Hand Hygiene" guidelines. RESULTS: Before the campaign, the overall hand hygiene compliance rate was 31.95% (340/1064, covert) versus 68.10% (790/1160, overt), and afterwards was 56.11% (615/1096, covert) versus 80.98% (1086/1341, overt). The infection rate was reduced by 22.62% (18.87% versus 14.60%). CONCLUSIONS: The Hawthorne effect and educational campaign markedly influenced compliance with hand hygiene recommendations. The results suggest that combining overt and covert observation methods, including regular feedback on hand hygiene compliance displayed on an electronic panel, may be a valid alternative to increase real hand hygiene compliance rates in hospital practice.

Synergistic activity of polymyxin B combined with vancomycin against carbapenem-resistant and polymyxin-resistant Acinetobacter baumannii: first in vitro study.

PURPOSE: The effect of a combination of polymyxin B (PMB) and vancomycin (VAN) was assessed against six Acinetobacter baumannii clinical isolates belonging to six different clusters (three PMB-susceptible and three PMB-resistant). METHODOLOGY: The synergistic effect of the PMB-VAN combination was determined with the checkerboard, time-kill, disk-diffusion and M.I.C.Evaluator assays. PMB-resistance was investigated with mcr-1 gene amplification and a mutant frequency assay. RESULTS: In the checkerboard assay, all PMB-resistant isolates showed a synergistic effect. The time-kill assay demonstrated that the PMB-VAN combination had a bactericidal effect at 24 h against isolates with a high mutant rate for PMB, suggesting that this combination may block the hypermutation of some isolates. No antagonism was detected. All PMB-resistant isolates also showed synergism in the disk-diffusion test, and a significant decrease in VAN MICs in the M.I.C.Evaluator assay. CONCLUSION: Our findings indicate that the PMB-VAN combination has a synergistic effect on A. baumannii, especially against PMB-resistant isolates.

What does the susceptible-dose dependent interpretive category for cefepime in ESBL-producing bacteria?

In this study, we investigated the frequency of isolates included in the susceptible-dose dependent (SDD) category, according to the Clinical and Laboratory Standards Institute guidelines, carrying blaTEM, blaSHV and blaCTX genes among 92 Klebsiella pneumoniae and 80 Enterobacter cloacae clinical isolates. The presence of one or more extended-spectrum ß-lactamases (ESBLs) genes was observed in 64% K. pneumoniae and 69% E. cloacae isolates. Nineteen isolates were included in SDD interpretive category criteria, of which 15 carried ESBL genes (seven K. pneumoniae and eight E. cloacae). Considering the high proportion of ESBL gene-containing isolates included in the SDD category (79%), we recommend that physicians exercise caution in the use of cefepime for treatment of infections caused by these isolates, reducing possible therapeutic failure, particularly in cases of ESBL-producing bacterial strains.

Strategies for the treatment of polymyxin B-resistant Acinetobacter baumannii infections.

In this study, the activity of meropenem (MEM), fosfomycin (FOF) and polymyxin B (PMB), alone and in combination, was analysed. In addition, optimisation of the pharmacodynamic index of MEM and FOF against six isolates of OXA-23-producing Acinetobacter baumannii (including three resistant to PMB) that were not clonally related was assessed. Antimicrobial combinations were evaluated by chequerboard analysis and were considered synergistic when the fractional inhibitory concentration index (FICI) was ≤0.5. Pharmacodynamic analyses of the MEM and FOF dosing schemes were performed by Monte Carlo simulation. The target pharmacodynamic index (%ƒT>MIC) for MEM and FOF was ≥40% and ≥70%, respectively, and a probability of target attainment (PTA) ≥0.9 was considered adequate. Among the PMB-resistant isolates, combinations of PMB+MEM and PMB+FOF+MEM showed the highest synergistic activity (FICI ≤0.125); isolates that were previously PMB-resistant were included in the susceptible category using CLSI interpretive criteria. Pharmacodynamic evaluation found that for a FOF minimum inhibitory concentration (MIC) of ≤16µg/mL, treatment both by bolus dosing and prolonged infusion achieved adequate PTA, whilst for MIC=32µg/mL only infusion achieved adequate PTA. For a MEM MIC of 4µg/mL, only the bolus treatment scheme with 1.5g q6h and the infusion schemes with 1.0g q8h, 1.5g q6h and 2.0g q8h achieved PTA ≥0.9. Results of antimicrobial and pharmacodynamic analyses can assist in treating infections caused by multidrug-resistant A. baumannii. However, in vivo clinical studies are essential to evaluate the true role of these compounds, including intravenous antimicrobial FOF therapy.

ISAba1/blaOXA-23: A serious obstacle to controlling the spread and treatment of Acinetobacter baumannii strains.

This study demonstrated a direct correlation between Acinetobacter baumannii clusters carrying the ISAba1/blaOXA-23 gene and increased minimal inhibitory concentrations for carbapenems and greater clonal diversity. Our findings showed that clusters carrying ISAba1 are widely distributed in our hospital, further complicating the treatment and control of infections caused by A baumannii.

A rapid and simple method to detect ESBL in Enterobacter cloacae based on MIC of cefepime.

INTRODUCTION: The aim of this study was to identify a rapid and simple phenotypic method for extended-spectrum ß-lactamase (ESBL) detection in Enterobacter cloacae. METHODS: A total of 79 consecutive, non-repeated samples of E. cloacae were evaluated. Four phenotypic methods were applied for ESBL detection, results were compared to multiplex polymerase chain reaction (PCR) as the gold standard reference method: 1) ceftazidime and cefotaxime disks with and without clavulanate, both with boronic acid added; 2) disk approximation using cefepime and amoxicillin/clavulanate; 3) ESBL screening by minimum inhibitory concentration (MIC) ≥ 16µg/mL and 4) by MIC ≥ 2µg/mL for cefepime. RESULTS: Method 4 showed the best combination of sensitivity (100%) and specificity (94%). CONCLUSIONS: MIC ≥ 2µg/mL for cefepime would be very useful for the phenotypic detection of ESBL in samples of E. cloacae.

Can ampicillin/sulbactam resistance in Acinetobacter baumannii be predicted accurately by disk diffusion?

The objective of this study was to compare the performance of disk diffusion and agar dilution for the determination of susceptibility to ampicillin/sulbactam (SAM), ceftazidime, cefepime, imipenem, meropenem, polymyxin B and tigecycline of 121 Acinetobacter baumannii clinical isolates. The antimicrobial susceptibility testing methods were performed as recommended by the Clinical and Laboratory Standards Institute (CLSI). For SAM, in addition the Etest method was performed according to the manufacturer's instructions. The error rates for the antimicrobial agents for 121 isolates tested were within the acceptable ranges established by the CLSI, with the exception of SAM and polymyxin B. For polymyxin B, there were 1.7% very major errors and for SAM there were 15% comparing disk diffusion with agar dilution. The very major error rate of SAM comparing the Etest with agar dilution was 10%. These high observed rates of very major error cast doubt on the disk diffusion and Etest techniques as appropriate methods for detecting resistance to SAM.

In vitro activity of polymyxins in combination with ß-lactams against clinical strains of Pseudomonas aeruginosa.

The emergence of multidrug-resistant (MDR) strains has made it difficult to treat infections caused by Pseudomonas aeruginosa. In order to develop new alternative therapies for the treatment of MDR P. aeruginosa infections, the antimicrobial activities of different antibiotic combinations have been studied in vitro and in vivo. In this study, the in vitro antimicrobial activities of six different combinations of polymyxins and ß-lactams against 34 clinical isolates of P. aeruginosa were evaluated. For the combinations tested by the checkerboard method, an indifferent effect was observed for all strains. However, 27 strains (19 MDR) showed reductions in their minimal inhibitory concentration (MIC) for at least one of the antibiotics in the combinations evaluated. Combination with polymyxins resulted in reductions of the ß-lactam MICs, with a change in the resistance category to susceptible in eight MDR strains. These results from the in vitro evaluation suggest that combinations of polymyxins and ß-lactams may significantly reduce the MICs of the antibiotics tested. These combinations require further evaluation for use in medical practice.

Nasal carriage of methicillin-resistant Staphylococcus aureus in university students.

In a study of university students, the percentage nasal carriage of Staphylococcus aureus was 40.8% (102/250). Of the isolates, MIC(50) of methicillin was 0.5 µg/mL and MIC(90) was 1 µg/mL. Six (5.8%) isolates were methicillin-resistant and carried the mecA gene. These results suggest that community-associated methicillin-resistant S. aureus may be spreading in Brazil.

Nasal carriage of methicillin-resistant Staphylococcus aureus in university students

In a study of university students, the percentage nasal carriage of Staphylococcus aureus was 40.8 percent (102/250). Of the isolates, MIC50 of methicillin was 0.5 µg/mL and MIC90 was 1 µg/mL. Six (5.8 percent) isolates were methicillin-resistant and carried the mecA gene. These results suggest that community-associated methicillin-resistant S. aureus may be spreading in Brazil.

Testes salivares e bacteriológicos para avaliação de risco de cárie / Bacteriologial and salivary tests for evaluation of caries risk

Os autores fazem uma breve revisão sobre os testes salivares e bacteriológicos comumente indicados na prática odontológica para avaliar os riscos de cárie. São abordados os seguintes tópicos: coleta de saliva estimulada, determinação do fluxo salivar e da capacidade tampão da saliva, contagem de lactobacilos e de estreptococos do grupo mutans da saliva. As técnicas de preparo dos reagentes e meios de cultura são incluídas no estudo para facilitar o uso dos testes no laboratório de análises clínicas.

Comparison of 3 alcohol gels and 70% ethyl alcohol for hand hygiene.

In a laboratory study, we demonstrated that 3 alcohol-based hand gels, commercially available in Brazil, were as effective as the traditional 70% ethyl alcohol (by weight) in removing clinical isolates of methicillin-resistant Staphylococcus aureus, Serratia marcescens, and Candida albicans from heavily contaminated hands of human volunteers.

Disinfection of gutta-percha cones with chlorhexidine

This study investigated the effectiveness of detergent and aqueous solutions of 2 percent chlorhexidine digluconate in decontaminating gutta-percha cones (gpc) contaminated with bacteria, yeast, or bacterial spores. Gutta-percha cones were contaminated with 10(7)-10(8) colony-forming units per milliliter (cfu/ml) of the following test organisms: Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, or Candida albicans. Spores of Bacillus subtilis were also tested. Contaminated gpc were treated with the chlorhexidine solutions for 1, 5, 10, or 15 min. Each cone was then transferred to a tube containing saline and the micoorganisms were recovered after homogenization for cfu determination. Both detergent and aqueous chlorhexidine solutions were effective in eliminating S. aureus, E. faecalis, and C. albicans cells adhered on the surface of gpc within 1 min of exposure. E. coli was eliminated in 5 min with detergent solution. The Bacillus subtilis spores were eliminated by chlorhexidine solutions within 5 min. The results of this study demonstrated that both aqueous and detergent solutions of 2 percent chlorhexidine digluconate were effective in decontaminating gpc within 5 minutes of exposure.

No presente estudo foi investigada a eficácia das soluções aquosa e detergente de digluconato de clorexidina a 2 por cento na descontaminação de cones de guta-percha (cgp) contaminados experimentalmente com bactérias, leveduras ou esporos bacterianos. Os cones foram contaminados com 10(7) a 10(8) unidades formadores de colônias por mililitro (ufc/ml) dos seguintes microrganismos teste: Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, ou Candida albicans. Esporos de Bacillus subtilis foram também testados. Os cones contaminados foram tratados com as soluções de clorexidina por, respectivamente, 1, 5, 10 ou 15 min. Cada cone foi então transferido para solução salina e homogeneizado para a determinação das ufc dos microorganismos. As soluções de clorexidina destruíram em 1 min as células de S. aureus, E. faecalis ou de C. albicans aderidas à superfície dos cgp. E. coli foi eliminada em 5 min com a solução detergente. Os esporos de Bacillus subtilis foram eliminados pelas soluções de clorexidina em 5 min. Os resultados deste estudo demonstraram que as soluções aquosa e detergente de clorexidina a 2 por cento foram efetivas na descontaminação dos cones de guta percha em 5 minutos.

Preliminary evaluation of adherence on abiotic and cellular surfaces of Acinetobacter baumannii strains isolated from catheter tips

The cell surface hydrophobicity and adhesion to abiotic and cellular surfaces was tested in five clinical strains of Acinetobacter baumannii isolated from catheter tips. Biochemical and molecular characteristics of these strains were also studied. Hydrophobicity was characterized by a test for affinity to xylene. Adhesion to abiotic surfaces (polystyrene, formica, latex and glass) was evaluated in Petri plates using the stamp technique. Buccal epithelial cells were used for tests of adhesion to cellular surfaces. Adhesion to the catheter was evaluated by repeatedly rinsing the catheters and rolling them over nutrient agar. Molecular typing of the strains was done by the ERIC-PCR technique. The degree of hydrophobicity of the strains varied from hydrophobic to hydrophilic. All the strains adhered to the cell surfaces and to the catheters, and three of them strongly adhered to latex, polystyrene and formica. Catheter adhesion was reduced by meropenem. We found a direct relationship between the degree of bacterial hydrophobicity and adhesion to the abiotic surfaces, but not with adhesion to cellular surfaces, which suggests that different mechanisms are involved in adherence.

Preliminary evaluation of adherence on abiotic and cellular surfaces of Acinetobacter baumannii strains isolated from catheter tips.

The cell surface hydrophobicity and adhesion to abiotic and cellular surfaces was tested in five clinical strains of Acinetobacter baumannii isolated from catheter tips. Biochemical and molecular characteristics of these strains were also studied. Hydrophobicity was characterized by a test for affinity to xylene. Adhesion to abiotic surfaces (polystyrene, formica, latex and glass) was evaluated in Petri plates using the stamp technique. Buccal epithelial cells were used for tests of adhesion to cellular surfaces. Adhesion to the catheter was evaluated by repeatedly rinsing the catheters and rolling them over nutrient agar. Molecular typing of the strains was done by the ERIC-PCR technique. The degree of hydrophobicity of the strains varied from hydrophobic to hydrophilic. All the strains adhered to the cell surfaces and to the catheters, and three of them strongly adhered to latex, polystyrene and formica. Catheter adhesion was reduced by meropenem. We found a direct relationship between the degree of bacterial hydrophobicity and adhesion to the abiotic surfaces, but not with adhesion to cellular surfaces, which suggests that different mechanisms are involved in adherence.

Improved laboratory safety by decontamination of unstained sputum smears for acid-fast microscopy.

Tubercle bacilli may survive in unstained heat-fixed sputum smears and may be an infection risk to laboratory staff. We compared the effectiveness of 1% and 5% sodium hypochlorite, 5% phenol, 2% glutaraldehyde, and 3.7% formalin in killing Mycobacterium tuberculosis present in smears prepared from 51 sputum samples. The smears were decontaminated by the tube and slide techniques. Phenol at 5%, glutaraldehyde at 2%, and buffered formalin at 3.7% for 1 min (tube technique) or for 10 min (slide technique) were effective in decontaminating sputum smears and preserved cell morphology and quantitative acid-fast microscopy results.

The effectiveness of alcohol gel and other hand-cleansing agents against important nosocomial pathogens

Nós comparamos a eficácia do álcool gel com a dos tradicionais agentes degermantes preconizados para a lavagem das mãos na remoção de amostras clínicas de Acinetobacter baumannii, Staphylococcus aureus resistente a meticilina, Escherichia coli, Enterococcus faecalis, Pseudomonas aeruginosa e Candida albicans das mãos artificialmente contaminadas. As pontas dos dedos dos voluntários (n=6) foram contaminadas com aproximadamente 106 de células/microrganismo teste. A seguir, as mãos foram lavadas com sabonete líquido não medicamentoso, álcool gel, álcool etílico 70 per center (concentração por peso) e soluções anti-sépticas detergentes de polivinilpirrolidona-iodo a 10 per center (PVP-I) e de gluconato de clorhexidina 4 per center. Os experimentos foram realizados segundo um quadrado latino com seis blocos aleatorizados 6 x 5. Os resultados foram estimados por ANOVA. Os produtos reduziram de 93,83 per center (sabão líquido) a 100 per center (PVP-I 10 per center) a população microbiana aplicada nas mãos. Em 4 dos 6 microrganismos testes analisados, o PVP-I 10 per center, o álcool gel, o álcool etílico 70 per center e a clorhexidina 4 per center mostraram uma taxa de remoção significantemente superior a do sabão líquido (P < 0,05). Os resultados confirmam a eficácia do álcool gel na higienização das mãos e sugerem que o PVP-I 10 per center, o álcool gel, o álcool etílico 70 per center e a clorhexidina 4 per center podem ser os agentes mais eficazes do que o sabão líquido não medicamentoso na remoção de Acinetobacter baumannii, Escherichia coli, Enterococcus faecalis e Candida albicans das mãos altamente contaminadas.

Effect of plaque accumulation and salivary factors on enamel demineralization and plaque composition in situ

Este estudo foi realizado para avaliar o efeito de alguns fatores salivares e da composição da placa dental na progressão da cárie in situ. O fluxo salivar, a capacidade tampão e os níveis de estreptococos mutans na saliva de 13 voluntários foram determinados inicialmente. Durante 3 períodos distintos de 4, 7 e 10 dias, eles utilizaram um dispositivo palatino contendo 4 blocos de esmalte bovino. Dez vezes ao dia, uma solução de sacarose a 20 por cento foi gotejada sobre os blocos de esmalte. Durante o experimento, os voluntários utilizaram um dentifrício não fluoretado. Estreptococos mutans (EM), cálcio (Ca) e polissacarídeos insolúveis (PI) foram quantificados na placa formada sobre os blocos após cada período. A desmineralização do esmalte foi avaliada através de microdureza de superfície, e a porcentagem de perda de dureza de superfície (porcentagem PDS) foi calculada em relação aos valores de dureza iniciais. Houve desmineralização do esmalte após cada período de acúmulo de placa (p < 0,05) e a porcentagem PDS aumentou com o tempo (de 13,8 para 48,3 por cento). As concentrações de Ca e PI na placa dental não foram diferentes entre os tempos experimentais, mas correlações significantes foram encontradas entre elas e a porcentagem PDS. Os fatores salivares avaliados inicialmente e os níveis de estreptococos mutans na placa não apresentaram correlação estatisticamente significante com a porcentagem PDS. Os resultados mostraram que a desmineralização do esmalte depende do tempo e está mais relacionada à composição do biofilme formado do que aos fatores salivares estudados.