Lourdes Botelho Garcia

Effectiveness of hand-cleansing agents for removing methicillin-resistant Staphylococcus aureus from contaminated hands

OBJECTIVE The effectiveness of hand-cleansing agents in removing a hospital strain of methicillin-resistant Staphylococcus aureus from artificially contaminated hands of five volunteers was studied. DESIGN The products used were plain liquid soap, ethyl alcohol 70% (by weight), 10% povidone-iodine liquid soap (PVP-I), and chlorhexidine gluconate (4%) detergent. The experiments were performed using a Latin square statistical design, with two 5x4 randomized blocks. The removal rates of S aureus cells from contaminated fingertips were estimated by analysis of variance, the response variable being the log10 reduction factor (RF), ie, log10 of the initial counts minus log10 of the final counts. In the first and second blocks, the fingertips of the volunteers were contaminated in mean with 3.76 log10 colony-forming units ([CFU] light-contamination hand) and 6.82 log10 CFU (heavy-contamination hand), respectively. RESULTS In the first block, there were significant differences between treatments (P<.05). The 10% PVP-I (RF, 3.76) and 70% ethyl alcohol (RF, 3.51) had significantly higher removal rates than plain liquid soap (RF, 1.96) and 4% chlorhexidine (RF, 1.91). In the second block, 10% PVP-I (RF, 4.39) and 70% ethyl alcohol (RF, 3.27) also were significantly more effective than plain liquid soap (RF, 1.77) and 4% chlorhexidine (RF, 1.37; P<.05). Plain liquid soap was significantly more effective than chlorhexidine (4%) detergent. CONCLUSIONS The results suggest that 10% PVP-I and 70% ethyl alcohol may be the most effective hand-cleansing agents for removing methicillin-resistant S aureus strain from either lightly or heavily contaminated hands.

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.

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.

In vitro evaluation of the antimicrobial activity of meropenem in combination with polymyxin B and gatifloxacin against Pseudomonas aeruginosa and Acinetobacter baumannii.

Abstract The antimicrobial activity of meropenem combined with either polymyxin B or gatifloxacin was evaluated by the checkerboard method against Pseudomonas aeruginosa (10 strains) and Acinetobacter baumannii (10 strains). In addition, the triple combination of polymyxin B, gatifloxacin, and meropenem was also studied as well as the polymyxin B and gatifloxacin combination. A partial synergism interaction between meropenem and polymyxin B was observed for 80% of the A. baumannii strains. In contrast, this combination showed an indifferent effect for 80% of the P. aeruginosa strains tested. The combination of meropenem and gatifloxacin showed synergism only for two strains of A. baumannii, and partial synergism and additive effect for seven strains and indifference for four strains of both species. For the strains of P. aeruginosa, the double combination of polymyxin B and gatifloxacin and the triple combination of meropenem, polymyxin B and gatifloxacin were indifferent for the majority of the strains tested, that is, 90 and 80% respectively.

Evolution of antimicrobial resistance of Acinetobacter baumannii in a university hospital

Aims:  To investigate the susceptibility pattern and the molecular epidemiology of Acinetobacter baumannii isolates in two periods (1994–1996 and 2004–2007) in Londrina University Hospital.

In vitro activity of polymyxins in combination with β-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 β-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 β-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 β-lactams may significantly reduce the MICs of the antibiotics tested. These combinations require further evaluation for use in medical practice.

High prevalence of children colonized with penicillin-resistant Streptococcus pneumoniae in public day-care centers

OBJECTIVES To investigate the prevalence of Streptococcus pneumoniae (pneumococci) in the nasopharynx of healthy children enrolled in public day-care centers of the municipality of Umuarama, state of Paraná, Brazil. The susceptibility of the pneumococcal strains to antimicrobial agents was also studied. METHODS Nasopharyngeal specimens from 212 children were collected from April to October 2008. After the specimens were seeded in blood agar and incubated at 37 degrees C for 24-48 hours, the colonies suspected of belonging to S. pneumoniae were identified using alpha-hemolysis, optochin sensitivity, and bile solubility test. Penicillin susceptibility was investigated using the disk diffusion and dilution tests. Susceptibility to the other antimicrobial agents indicated for the treatment of pneumococcal infections was investigated using the disk diffusion test. RESULTS The prevalence of nasopharyngeal pneumococci was 43.4% (92/212), with higher rates in children between 2 and 5 years old (p = 0.0005). There was no significant difference between sexes. Intermediate and full resistance to penicillin were found in 34.8 (32/92) and 22.8% (21/92) isolates, respectively. Sixty-seven strains (72.8%) were resistant to sulfamethoxazole-trimethoprim, eight (8.7%) were resistant to erythromycin, and six (6.5%) to tetracycline. One strain was resistant to clindamycin (1.1%) and another was resistant to chloramphenicol (1.1%). All strains were sensitive to levofloxacin, ofloxacin, rifampicin, telithromycin, linezolid, and vancomycin. Nine strains were considered multiresistant because they were resistant to three or more classes of antimicrobial agents. CONCLUSIONS The present study detected a high prevalence of healthy children colonized with penicillin-resistant S. pneumoniae strains who may be important reservoirs of this pathogen in the community.

Survival of vancomycin-intermediate Staphylococcus aureus on hospital surfaces

BACKGROUND Contaminated surfaces play an important role in the transmission of certain pathogens that are responsible for healthcare-associated infections. Although previous studies have shown that meticillin-resistant Staphylococcus aureus (MRSA) can survive on dry surfaces at room temperature, no published data regarding vancomycin-intermediate S. aureus (VISA) are available to date. AIM To compare the survival time on different types of surfaces, cell-surface hydrophobicity, adherence to abiotic surfaces and biofilm formation of meticillin-susceptible S. aureus (MSSA), MRSA and VISA. METHODS Survival of the S. aureus strains was tested on latex, cotton fabric, vinyl flooring and formica. Cell-surface hydrophobicity was determined using the hydrocarbon interaction affinity method. Adhesion to abiotic surfaces was tested on granite, latex (gloves), glass, vinyl flooring and formica. Biofilm formation was evaluated at 6, 12, 24 and 48 h. FINDINGS All of the samples survived on the vinyl flooring and formica for at least 40 days. VISA survived on both surfaces for more than 45 days. All of the strains were highly hydrophobic. VISA adhered to latex, vinyl flooring and formica. Biofilm formation increased for all of the tested strains within 6-24 h. CONCLUSION VISA present high survival, adherence and cell-surface hydrophobicity. Therefore, as the treatment of patients with VISA is a significant challenge for clinicians, greater care with cleaning and disinfection of different types of surfaces in healthcare facilities is recommended because these may become important reservoirs of multi-resistant pathogens.

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.

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

Nos comparamos a eficacia do alcool gel com a dos tradicionais agentes degermantes preconizados para a lavagem das maos na remocao de amostras clinicas de Acinetobacter baumannii, Staphylococcus aureus resistente a meticilina, Escherichia coli, Enterococcus faecalis, Pseudomonas aeruginosa e Candida albicans das maos artificialmente contaminadas. As pontas dos dedos dos voluntarios (n=6) foram contaminadas com aproximadamente 106 de celulas/microrganismo teste. A seguir, as maos foram lavadas com sabonete liquido nao medicamentoso, alcool gel, alcool etilico 70% (concentracao por peso) e solucoes anti-septicas detergentes de polivinilpirrolidona-iodo a 10% (PVP-I) e de gluconato de clorhexidina 4%. 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% (sabao liquido) a 100% (PVP-I 10%) a populacao microbiana aplicada nas maos. Em 4 dos 6 microrganismos testes analisados, o PVP-I 10%, o alcool gel, o alcool etilico 70% e a clorhexidina 4% mostraram uma taxa de remocao significantemente superior a do sabao liquido (P < 0,05). Os resultados confirmam a eficacia do alcool gel na higienizacao das maos e sugerem que o PVP-I 10%, o alcool gel, o alcool etilico 70% e a clorhexidina 4% podem ser os agentes mais eficazes do que o sabao liquido nao medicamentoso na remocao de Acinetobacter baumannii, Escherichia coli, Enterococcus faecalis e Candida albicans das maos altamente contaminadas.