Characterization, Antioxidant and Antibacterial Potentials of Tamarindus indica L. Fruit Pulp Extract Loaded O/W Nanoemulsions

Abstract The main purposes of the current study were to formulate o/w nanoemulsions as a carrier for Tamarindus indica (tamarind) fruit pulp extract and to study the antioxidant and antibacterial potentials of nanoemulsions containing tamarind extract, focusing on cosmetic/hygiene applications. The o/w nanoemulsions using a mixture of Tween 80 and Span 80 as an emulsifier (5%w/w) were prepared by a high pressure homogenization process. Two concentrations of sweet tamarind extract, 3.3 and 6.6%w/w, based on the bioactivity study, were incorporated into the blank nanoemulsions to produce loaded nanoemulsions, F1-3.3TE (3.3%) and F1- 6.6TE (6.6%). As compared with the unloaded nanoemulsion, both tamarind extract loaded nanoemulsions showed reduced pH and significantly increased viscosity. Overall, the loaded nanoemulsions had droplet sizes of approximately 130 nm, zeta potential around -38 mV and polydispersity index (PDI) values less than 0.2. The nanoemulsion F1-3.3TE had better stability (e.g. significantly greater % tartaric acid content and lesser PDI value) than the nanoemulsion F1-6.6TE did. The antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl assay revealed that the nanoemulsions F1-3.3TE and F1-6.6TE had scavenging activities of 81.66 ± 0.77% and 63.80 ± 0.79%, respectively. However, antioxidant activity of these two formulations decreased under stress conditions (heating-cooling cycles). Such incidence did not occur for their antibacterial properties investigated by agar well diffusion technique. The two formulations exhibited inhibition zones of approximately 24.0-27.7 mm against Staphylococcus aureus and Staphylococcus epidermidis, responsible for malodor of underarms. The results suggest the potential of using sweet tamarind pulp extract loaded nanoemulsions as hygiene products.

Reduced susceptibility to vancomycin and biofilm formation in methicillin-resistant Staphylococcus epidermidis isolated from blood cultures

This study aimed to correlate the presence of ica genes, biofilm formation and antimicrobial resistance in 107 strains of Staphylococcus epidermidis isolated from blood cultures. The isolates were analysed to determine their methicillin resistance, staphylococcal cassette chromosome mec (SCCmec) type, ica genes and biofilm formation and the vancomycin minimum inhibitory concentration (MIC) was measured for isolates and subpopulations growing on vancomycin screen agar. The mecA gene was detected in 81.3% of the S. epidermidis isolated and 48.2% carried SCCmec type III. The complete icaADBC operon was observed in 38.3% of the isolates; of these, 58.5% produced a biofilm. Furthermore, 47.7% of the isolates grew on vancomycin screen agar, with an increase in the MIC in 75.9% of the isolates. Determination of the MIC of subpopulations revealed that 64.7% had an MIC ≥ 4 μg mL-1, including 15.7% with an MIC of 8 μg mL-1 and 2% with an MIC of 16 μg mL-1. The presence of the icaADBC operon, biofilm production and reduced susceptibility to vancomycin were associated with methicillin resistance. This study reveals a high level of methicillin resistance, biofilm formation and reduced susceptibility to vancomycin in subpopulations of S. epidermidis. These findings may explain the selection of multidrug-resistant isolates in hospital settings and the consequent failure of antimicrobial treatment.

Methicillin-resistant Staphylococcus sp. colonizing health care workers of a cancer hospital

The aim of the study was to analyze epidemiological and microbiological aspects of oral colonization by methicillin-resistant Staphylococcus of health care workers in a cancer hospital. Interview and saliva sampling were performed with 149 health care workers. Antimicrobial resistance was determined by disk diffusion and minimum inhibitory concentration. Polymerase Chain Reaction, Internal Transcribed Spacer-Polymerase Chain Reaction and Pulsed Field Gel Electrophoresis were performed for genotypic characterization of methicillin-resistant Staphylococcus. Risk factors were determined by logistic regression. Methicillin-resistant Staphylococcus colonization prevalence was 19.5%, denture wearing (p = 0.03), habit of nail biting (p = 0.04) and preparation and administration of antimicrobial (p = 0.04) were risk factors identified. All methicillin-resistant Staphylococcus were S. epidermidis, 94.4% of them had mecA gene. Closely related and indistinguishable methicillin-resistant S. epidermidis were detected. These results highlight that HCWs which have contact with patient at high risk for developing infections were identified as colonized by MRSE in the oral cavity, reinforcing this cavity as a reservoir of these bacteria and the risk to themselves and patients safety, because these microorganisms may be spread by coughing and talking.

Evaluation of polymerase chain reaction, conventional and MRSA screen latex agglutination methods for detection of methicillin-resistant, -borderline and -susceptible Staphylococcus aureus.

Methicillin-resistant Staphylococcus aureus (MRSA), is difficult and expensive to treat, therefore early screening is essential. Several phenotypic and genotypic methods are used to detect MRSA; however, the method of choice remains problematic. We have evaluated four phenotypic methods, broth microdilution (MIC), oxacillin disk agar diffusion (ODD), oxacillin screening salt agar (OSS), and a new rapid phenotypic (MRSA screen latex agglutination, MSLA) with the genotypic gold standard of PCR mecA detection to determine the most appropriate method for routine laboratory use. We randomly collected 203 S. aureus isolates from patients and carriers at two hospitals in Thailand. Using MIC method, three sub-groups were differentiated from among these isolates, namely MRSA (106 isolates), borderline-resistant S. aureus (BRSA) (65 isolates), and methicillin-susceptible S. aureus (MSSA)(32 isolates). A total of 10 methicillin-resistant S. epidermidis (MRSE) isolates were also included. The sensitivity and specificity of MIC, ODD, OSS, and MSLA were 99 and 96, 100 and 97, 100 and 97, and 100 and 100%, respectively. Our study indicated that ODD is still appropriate for routine laboratory. MSLA had the highest sensitivity and specificity and is rapid but expensive, so is the most appropriate method for emergency cases. MIC method was better for BRSA detection and OSS method was more appropriate for screening clinical specimens and carriers.

Estratégias atuais para o tratamento da infecção em revascularização infra-inguinais / Current strategies for the management of infection in lower extremity revascularization

A infecção pós-operatória representa uma complicação grave em revasculatizaçóes de membros inferiores e sua prevenção, controle e tratamento são um desafio ao cirurgião vascular. Os pacientes que desenvolvem essa infecção apresentam não só morbidade aumentada, como também mortalidade significativa. A infecção pós-operatória é difícil de ser erradicada e, se não for adequadamente tratada, pode causar falência do enxerto vascular, hemorragia e sepsis, sendo de extrema importância o uso de medidas para a prevenção da infecção pós-operatória. A utilização de técnicas menos invasivas para a retirada.da veia safena magna em cirurgias de revascularização de membros inferiores e o uso de próteses impregnadas com sais de prata e antibióticos são exemplos de medidas profiláticas utilizadas. O sucesso do tratamento requer uma ampla compreensão da fisiopatogenia do processo, assim como o uso criterioso das várias modalidades terapêuticas, entre elas: a ntibioticoterapia apropriada, o desbridamento cirúrgico e a revascularização quando necessário. Atualmente, o uso de próteses impregnadas com rifampicina tem se mostrado eficaz no tratamento de infecção causada pelo Staphylococcus epidermidis. Os resultados iniciais com o uso de enxertos autólogos criopreservados e a utilização da veia femoral superficial como substituto arterial são promissores. O objetivo deste artigo é fazer uma revisão atualizada sobre a avaliação e o tratamento da infecção em revascularizaçóes infrainguinais.

Study of coagulase negative staphylococci isolated from blood and CSF cultures.

Coagulase negative Staphylococci (CONS) which were considered as laboratory contaminants and normal flora of skin in man, have emerged as opportunistic pathogens. The infection with CONS has been reported since 1950 with increasing frequency and has been implicated as the causative agents of certain categories of patients viz, neonates with sepsis, cardiac patients with prosthetic valves, immunocompromided patients which include end-renal stage disease, and renal transplantation, burns and cancer patient. These are causing problems to clinicians because of their drug resistance. 180 strains of CONS isolated from blood and CSF during the period of 2 years (Jan 1997-Dec 1998) were studied. Not only they were resistant to Penicillin (P), Ampicillin, (Amp), Oxacillin (Ox), but also developing resistance to Vancomycin (Van) which pose a therapeutic problem. So this study was undertaken and this area needs further exploration.

Species identification & methicillin resistance of coagulase negative staphylococci from clinical specimens.

A total of 75 strains of coagulase negative staphylococci were isolated in pure culture from different specimens from patients suffering from various deep seated staphylococcal infections undergoing treatment between November, 1985 and December, 1986. Using the Baird Parker classification system, Staphylococcus epidermidis was the commonest isolate found (60%) of which biotype 1 was the most frequent (51.1%). Twenty seven (36%) untypable strains could be typed using Kloos and Schleifer's classification system. These strains were identified as Staph. cohnii (10), Staph. hominis (8), Staph. capitis (4), Staph. haemolyticus (3), Staph. simulans (1), and Staph. warneri (1). Three Staph. saprophyticus strains were isolated from patients of urinary tract infection. Methicillin resistant strains (14.6%) were isolated mainly from patients of meningitis, urinary tract infections and endocarditis. All these strains were sensitive to vancomycin. Coagulase negative staphylococci thus can cause a number of human infections and should no longer be regarded as harmless commensals.