Comparison of the Three Phenotypic Methods to Detect Biofilm Production in Coagulase Negative Staphylococci

Coagulase Negative Staphylococci species (CoNS) have been recognized as etiological agents in wide variety of infections, patients with implants and devices. CoNS has the ability to produce biofilm which is responsible for resistance to host defense mechanisms and to the antibiotics. Hence this study was undertaken to study biofilm production by the isolated species of CoNS by three different phenotypic methods and compare these methods for biofilm production.METHODSIn this cross-sectional study, 200 CoNS isolates from clinically significant samples were identified up to species level by conventional phenotypic methods. Biofilm production was detected by Tissue Culture Plate method (TCP), Standard Tube method (ST) and Congo Red Agar Plate method (CRA). Biofilm production in test strains were compared with reference strains.RESULTSOut of 200 CoNS isolates, 122 were positive by TCP method, 106 by ST method & 67 by CRA method for biofilm production. Considering TCP method as gold standard, sensitivity, specificity, PPV and NPV of ST & CRA method were found to be 86.06%, 98.71%, 99.05%, 81.91% and 54.09%, 98.71%, 98.50% and 57.89% respectively. Analysis of Kappa agreement between TCP and ST method showed good agreement while between TCP & CRA, moderate agreement. Comparison of ST and CRA method with TCP by Pearson correlation coefficient test showed strong association between ST and TCP method (p= 0.006) & poor association between TCP and CRA method. (p<0.01).CONCLUSIONSBiofilm production by TCP method was higher compared to the other methods. ST method is comparable to TCP but CRA alone cannot be considered for biofilm detection in CoNS. ST method can be used in routine as it gives reliable results with good sensitivity & specificity and is easy to perform.

Oral Candida Carriage Including Speciation, Biofilm Production And Correlation With Occurrence Of Dental Caries In Student Population

The study was done to establish oral carriage of Candida, speciation, assay biofilm production and correlate the oral Candida carriage with occurrence of dental caries in students. Swab samples from oral cavity were collected from 206 students and were cultured for yeasts. Isolated yeasts were identified and detected for Biofilm production. Results:Overall Candida carriage was found in 90 of the 206 students (75 with caries). The rate of Candida carriage in students with caries (64%) was significantly higher as compared to overall carriage in students (43.7%). Atotal of 123 Candida strains were isolated including C albicans (63%), C tropicalis (23 %), C. parapsilosis (6 %), C. glabrata (4 %) and C. krusei (4 %). Biofilm production by C albicans was less frequent (42. 85%) than that by non-C albicans (63.33 %). and was significantly higher in students with caries than from without caries. Conclusion:We found a significant risk of dental caries with oral Candida carriage rates in student population. Candida albicans was the most common species isolated. Biofilm production was implicated in Candida virulence and was more important for non- C.albicans than C.albicans strains to establish infections.

Intramammary treatment with gentamicin in lactating cows with clinical and subclinical mastitis / Tratamento intramamário com gentamicina em vacas com mastite clínica e subclínica durante a lactação

The study evaluated the microbiological profile of milk samples collected before and after mastitis treatment with gentamicin and investigated biofilms production and antimicrobial susceptibility of Staphylococcus spp. isolated. The presence of gentamicin residues in milk after the recommended withdrawal period was also evaluated. Antimicrobial residues were analyzed by Delvotest® SP NT over a period of 12 days beginning after 24 hours the last gentamicin application. Some of Staphylococcus spp. isolates were biofilm producers (19.05%). Staphylococcus spp. showed high levels of resistance to neomycin (16.95%), penicillin G (10.17%), and ampicillin (10.17%). Multidrug resistance to all antibiotics tested was observed in 1.69% of the Staphylococcus spp. isolates. Among 1440 mammary quarter milk samples 24.95% presented gentamicin residues after the withdrawal period. Gentamicin residues were also detected in 3.8% of samples from calibrated glass recorder jar (n=383) 4.1 days after treatment. The indiscriminate use of antibiotics may lead to the emergence of multidrug-resistant strains as well as increasing the risk of presence of residues of these drugs in milk. These problems affect the milk quality and may become a public health problem.

Este estudo avaliou o perfil microbiológico de amostras de leite colhidas antes e após o tratamento da mastite com gentamicina e investigou a produção de biofilmes e o perfil de susceptibilidade antimicrobiana de Staphylococcus spp. isolados. Avaliou-se também a presença de resíduos de gentamicina no leite após o período de carência recomendado. Resíduos de antimicrobianos foram analisados por Delvotest® SP NT ao longo de um período de 12 dias, iniciando 24 horas após a última aplicação de gentamicina. Alguns dos Staphylococcus spp. isolados apresentaram produção de biofilmes (19,05%). Staphylococcus spp. apresentaram elevados níveis de resistência à neomicina (16,95%), penicilina G (10,17%), e ampicilina (10.17%). Multirresistência a todos os antibióticos testados foi observada em 1,69% dos Staphylococcus spp. isolados. Do total de 1440 amostras de leite de quartos mamários, 24,95% apresentaram resíduos de gentamicina após o período de carência. Resíduos de gentamicina também foram detectados em 3,8% das amostras de balões volumétricos coletores de leite (n= 383), 4,1 dias após o tratamento. O uso indiscriminado de antibióticos pode levar ao aparecimento de estirpes multirresistentes bem como o aumento do risco da presença de resíduos destas drogas no leite. Esses problemas afetam a qualidade do leite e podem tornar-se um problema de saúde pública.

Influence of papain in biofilm formed by methicillin-resistant Staphylococcus epidermidis and methicillin-resistant Staphylococcus haemolyticus isolates

Methicillin-resistant Staphylococcus epidermidis (MRSE) and methicillin-resistant Staphylococcus haemolyticus (MRSHa) are important coagulase-negative staphylococci. They are often isolated from bacteremia in humans mainly due to their ability to form biofilm on the surfaces of medical devices. Papain is a complex mixture of proteolytic enzymes and peroxidases extracted from the latex of Carica papaya and it is recognized by accelerating the healing process of wounds. This study aimed to evaluate the ability of the MRSE and MRSHa isolates to produce biofilms. Besides this, the ability of papain to inhibit the formation of biofilms or to disrupt the ones already formed by those bacteria was analyzed. Thirty MRSHa and 30 MRSE were isolated from bacteremia and used in this study. It was observed that papain has ability to reduce biofilms formed by MRSE (p < 0.06) and by MRSHa (p = 0.0005). In addition, papain was able to disrupt mature biofilms made by MRSE (p = 0.014). No antibacterial activity of papain was observed for any isolates of MRSE and MRSHa tested. Papain has been demonstrated as a potential product for reducing biofilm.

Staphylococcus epidermidis resistente à meticilina (MRSE) e Staphylococcus haemolyticus resistente à meticilina (MRSHa) são importantes estafilococos coagulase negativa. São frequentemente isolados em bacteremia humana, principalmente devido à capacidade de formar biofilmes nas superfícies de dispositivos médicos introduzidos no organismo. A papaína é mistura complexa de enzimas proteolíticas e peroxidases extraídas do látex de Carica papaya, reconhecida por acelerar os processos de cura de feridas. Este estudo teve como objetivo avaliar a capacidade dos MRSE e MRSHa em produzir biofilmes e analisar a capacidade da papaína em inibir a formação de biofilme ou desintegrar biofilmes já formados por essas bactérias. Observou-se que a papaína tem capacidade de reduzir a formação de biofilme por MRSE (p < 0,06) e MRSHa (p = 0,0005). Além disso, a papaína foi capaz de desintegrar biofilme maduro formado por MRSE (p = 0,014). Nenhuma atividade antibacteriana da papaína foi observada para qualquer das duas espécies de bactérias testadas. A papaína mostrou-se produto potencial para reduzir biofilme.

Glucose & sodium chloride induced biofilm production & ica operon in clinical isolates of staphylococci.

Background & objectives: All colonizing and invasive staphylococcal isolates may not produce biofilm but may turn biofilm producers in certain situations due to change in environmental factors. This study was done to test the hypothesis that non biofilm producing clinical staphylococci isolates turn biofilm producers in presence of sodium chloride (isotonic) and high concentration of glucose, irrespective of presence or absence of ica operon. Methods: Clinical isolates of 100 invasive, 50 colonizing and 50 commensal staphylococci were tested for biofilm production by microtiter plate method in different culture media (trypticase soy broth alone or supplemented with 0.9% NaCl/ 5 or 10% glucose). All isolates were tested for the presence of ica ADBC genes by PCR. Results: Biofilm production significantly increased in the presence of glucose and saline, most, when both glucose and saline were used together. All the ica positive staphylococcal isolates and some ica negative isolates turned biofilm producer in at least one of the tested culture conditions. Those remained biofilm negative in different culture conditions were all ica negative. Interpretation & conclusions: The present results showed that the use of glucose or NaCl or combination of both enhanced biofilm producing capacity of staphylococcal isolates irrespective of presence or absence of ica operon.