Diagnostic value of pediatric blood culture bottles for acute postoperative endophthalmitis

OBJECTIVE: To report our experience using conventional culture methods (CM) and pediatric blood culture bottles (PBCBs) for vitreous sample culture of acute postoperative endophthalmitis. METHODS: A retrospective study was conducted at the Department of Ophthalmology, Hospital das Clinicas, HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, BR, from January 2010 to December 2015, and it included 54 patients with clinically suspected acute postoperative endophthalmitis. Vitreous samples were obtained by vitreous tap or vitrectomy. Samples from January 2010 to December 2011 were cultivated in CM, whereas samples from January 2012 to December 2015 were inoculated in PBCBs. The measured outcome was the yield of positive cultures. RESULTS: Twenty cases were included in the CM group, and 34 cases were included in the PBCB group. The yield of positive cultures in PBCBs (64.7%) was significantly higher than that in conventional CM (35%, p=0.034). Staphylococcus epidermidis and Streptococcus viridans were the two most commonly found agents. CONCLUSION: PBCBs can be used successfully in clinically suspected endophthalmitis. The method showed a higher yield of positive cultures than the conventional method. This technique appears to have several advantages over the traditional method: it saves time, as only one medium needs to be inoculated; transportation to a laboratory is easier than in the traditional method, and there is no need to maintain a supply of fresh agar media. The use of PBCBs may be recommended as the primary method for microbiological diagnosis and is especially suitable for office settings and remote clinics.

Occurrence of the vanA gene in Staphylococcus epidermidis from nasopharyngeal secretion of Health-Care Workers, Recife, Brazil

Abstract INTRODUCTION: The increasing reports of vancomycin-resistant Staphylococcus strains (VRS) haves caused concern worldwide, from the laboratory detection to patient management. This study aimed to identify the occurrence of VRS strains among healthcare professionals from a university hospital. METHODS: A total of 102 Staphylococcus sp. isolates from healthcare professionals, obtained in a previous study were evaluated according to standard techniques for VRS detection. RESULTS: After screening inoculation of plates containing 6µg/ml of vancomycin, 19 resistant isolates were identified. The susceptibility profile to other antimicrobials revealed 18 multidrug resistant isolates. The minimum inhibitory concentration (MIC) was determined by E-test and broth microdilution. According to E-tests, of 19 isolates grown in BHI-V6, four isolates presented MIC ≥ 128 µg/ml, seven with MIC ranging from 4 to 8 µg/ml, and eight with MIC ≤ 2µg/ml. By broth microdilution, 14 isolates presented MIC ≤ 2 µg/ml and five with MIC ≥ 16µg/ml. The presence of the gene vanA was determined by PCR in the five resistant isolates, and this gene was detected in one of the strains. Furthermore, among the 19 strains, the gene mecA was found in 13 (39,4%) isolates, including the strain carrying the gene vanA. CONCLUSIONS: Based on these results, we highlight the presence of one strain carrying both vanA and the mecA genes, as well as multidrug-resistant strains colonizing healthcare professionals, and their importance as potential vectors to spread strains carrying resistance genes in the hospital environment.

Molecular epidemiology of coagulase-negative bloodstream isolates: detection of Staphylococcus epidermidis ST2, ST7 and linezolid-resistant ST23

Abstract The mechanisms contributing to persistence of coagulase-negative staphylococci are diverse; to better understanding of their dynamics, the characterization of nosocomial isolates is needed. Our aim was to characterize phenotypic and molecular characteristics of Staphylococcus epidermidis and Staphylococcus haemolyticus human blood isolates from two tertiary care hospitals in Mexico, the Hospital Universitario in Monterrey and the Hospital Civil in Guadalajara. Antimicrobial susceptibility was determined. Biofilm formation was assessed by crystal violet staining. Detection of the ica operon and Staphylococcal Cassette Chromosome mec typing were performed by PCR. Clonal relatedness was determined by Pulsed-fiel gel electrophoresis and Multi locus sequence typing. Methicillin-resistance was 85.5% and 93.2% for S. epidermidis and S. haemolyticus, respectively. Both species showed resistance >70% to norfloxacin, clindamycin, levofloxacin, trimethoprim/sulfamethoxazole, and erythromycin. Three S. epidermidis and two S. haemolyticus isolates were linezolid-resistant (one isolate of each species was cfr+). Most isolates of both species were strong biofilm producers (92.8% of S. epidermidis and 72.9% of S. haemolyticus). The ica operon was amplified in 36 (43.4%) S. epidermidis isolates. SCCmec type IV was found in 47.2% of the S. epidermidis isolates and SCCmec type V in 14.5% of S. haemolyticus isolates. No clonal relatedness was found in either species. Resistance to clindamycin, levofloxacin, erythromycin, oxacillin, and cefoxitin was associated with biofilm production for both species (p < 0.05). A G2576T mutation in 23S rRNA gene was detected in an S. haemolyticus linezolid-resistant isolate. All linezolid-resistant S. epidermidis isolates belonged to ST23; isolate with SCCmec type IV belonged to ST7, and isolate with SCCmec type III belonged to ST2. This is the first report of ST7 in Mexico. There was a high genetic diversity in both species, though both species shared characteristics that may contibute to virulence.

Panophthalmitis with orbital cellulitis following glaucoma drainage implant surgery in a pediatric patient / Panoftalmite com celulite orbitária após implante de drenagem em glaucoma congênito

ABSTRACT Here we report a case of childhood glaucoma refractory to angle and trabeculectomy surgery. The patient was treated with an Ahmed™ drainage implant that was subsequently complicated by rapid-onset panophthalmitis and orbital cellulitis. Intravenous and intravitreal antibiotic therapy was initiated and the drainage tube was removed. The infectious process resolved within 3 weeks; however, phthisis bulbi developed subsequently.

RESUMO Relato de um caso de uma criança portadora de glaucoma congênito primário, refratário a cirurgias angulares e trabeculectomias prévias, submetido à implante de drenagem do tipo Ahmed®. O paciente evoluiu com panoftalmite e celulite orbitária de aparecimento súbito, sendo submetido à remoção do tubo e antibioticoterapia endovenosa e intravítrea. O processo infeccioso foi resolvido em três semanas, porém o olho evoluiu para phthisis bulbi.

The prevalence of genotypes that determine resistance to macrolides, lincosamides, and streptogramins B compared with spiramycin susceptibility among erythromycin-resistant Staphylococcus epidermidis

Coagulase-negative staphylococci, particularly Staphylococcus epidermidis, can be regarded as potential reservoirs of resistance genes for pathogenic strains, e.g., Staphylococcus aureus. The aim of this study was to assess the prevalence of different resistance phenotypes to macrolide, lincosamide, and streptogramins B (MLSB) antibiotics among erythromycin-resistant S. epidermidis, together with the evaluation of genes promoting the following different types of MLSB resistance:ermA, ermB, ermC,msrA, mphC, and linA/A’. Susceptibility to spiramycin was also examined. Among 75 erythromycin-resistantS. epidermidis isolates, the most frequent phenotypes were macrolides and streptogramins B (MSB) and constitutive MLSB (cMLSB). Moreover, all strains with the cMLSB phenotype and the majority of inducible MLSB (iMLSB) isolates were resistant to spiramycin, whereas strains with the MSB phenotype were sensitive to this antibiotic. The D-shape zone of inhibition around the clindamycin disc near the spiramycin disc was found for some spiramycin-resistant strains with the iMLSB phenotype, suggesting an induction of resistance to clindamycin by this 16-membered macrolide. The most frequently isolated gene was ermC, irrespective of the MLSB resistance phenotype, whereas the most often noted gene combination wasermC, mphC, linA/A’. The results obtained showed that the genes responsible for different mechanisms of MLSB resistance in S. epidermidis generally coexist, often without the phenotypic expression of each of them.

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.

Genotypic study documents divergence in the pathogenesis of bloodstream infection related central venous catheters in neonates

OBJECTIVE: To investigate the pathogenesis of bloodstream infection by Staphylococcus epidermidis, using the molecular epidemiology, in high-risk neonates. METHODS: We conducted a prospective study of a cohort of neonates with bloodstream infection using central venous catheters for more than 24 h. "National Healthcare Safety Network" surveillance was conducted. Genotyping was performed by DNA fingerprinting and mecA genes and icaAD were detected by multiplex-PCR. RESULTS: From April 2006 to April 2008, the incidence of bloodstream infection and central venous catheter-associated bloodstream infection was 15.1 and 13.0/1000 catheter days, respectively, with S. epidermidis accounting for 42.9% of episodes. Molecular analysis was used to document the similarity among six isolates of bloodstream infection by S. epidermidis from cases with positive blood and central venous catheter tip cultures. Fifty percent of neonates had bloodstream infection not identified as definite or probable central venous catheter-related bloodstream infection. Only one case was considered as definite central venous catheter-related bloodstream infection and was extraluminally acquired; the remaining were considered probable central venous catheter-related bloodstream infections, with one probable extraluminally and another probable intraluminally acquired bloodstream infection. Additionally, among mecA+ and icaAD+ samples, one clone (A) was predominant (80%). A polyclonal profile was found among sensitive samples that were not carriers of the icaAD gene. CONCLUSIONS: The majority of infections caused by S. epidermidis in neonates had an unknown origin, although 33.3% appeared to have been acquired intraluminally and extraluminally. We observed a polyclonal profile between sensitive samples and a prevalent clone (A) between resistant samples. .

Multi drug resistance in strong biofilm forming clinical isolates of Staphylococcus epidermidis

Staphylococcus epidermidis which exists in healthy human skin as a commensal inhabitant is also an important pathogen forming biofilms on many surfaces and recently, increased resistance traits were suggested to be acquired in biofilm environments. In this study; clinical Prevalences, antibiotic resistances and biofilm formations of S. epidermidis strains were determined and comparison of all these findings with each other was carried out in order to take precautions against them and figure out if high biofilm forming S. epidermidis strains display multi drug resistance. According to our results; samples of wound and blood were the most S. epidermidis isolated clinical materials (40%; 35%) and cardiothoracic surgery was the most S. epidermidis observed service unit. All of these strains were sensitive to vancomycin, however 65% of them showed resistance to all β-lactam antibiotics (Penicillin, Oxacillin, Amoxicilin / Clavulonic acid), used in this study and 60% of all S. epidermidis strains were found as multi drug resistant. When the results of strong biofilm forming S. epidermidis strains are examined; they were isolated from sample of blood and service unit of cardiovascular surgery in highest frequency and 80% of them were β-lactam resistant whereas 100% of them were multi drug resistant. One of these multi drug resistant strains which was resistant to maximum amount of different antimicrobial classes, was also observed as maximum biofilm forming strain among all the other S. epidermidis isolates. Multi drug resistance in strong biofilm forming strains shows that; biofilms play a role in antimicrobial resistance traits of S. epidermidis.

Contaminacao microbiana de punhos de jalecos durante a assistencia a saude / Microbial contamination of cuffs lab coats during health care / Contaminacion microbiana de los punos de batas de laboratorio durante la atencion a la salud

O estudo objetivou avaliar a contaminação bacteriana em jalecos de acadêmicos de enfermagem após a sua utilização em práticas assistenciais à saúde. Realizou-se estudo quantitativo e descritivo, no qual os jalecos dos acadêmicos foram recolhidos, lavados e passados de forma padronizada e usados durante quatro horas em atividades assistenciais. Subsequentemente, coletaram-se amostras dos punhos com hastes de algodão estéreis para serem incubadas; analisando-se posteriormente o crescimento microbiano por meio de análise morfológica pelo método Gram e antibiograma. Observou-se crescimento bacteriano dos microrganismos Staphylococcus aureuse Staphylococcus epidermidis em 50% das amostras coletadas, sendo que o Staphylococcus aureus, encontrado no ambulatório de atendimento a portadores de feridas, apresentou resistência aos antibióticos Vancomicina, Cloranfenicol e Sulfonamidas. Os dados demonstraram que os jalecos utilizados durante as atividades assistenciais, mesmo em curtos períodos, são contaminados por cepas resistentes a antibióticos e que potencialmente podem ser causadores de infecção relacionada a assistência à saúde.

The study aimed to evaluate the bacterial contamination in lab coats worn by nursing students, before and after being worn in health care practices. A quantitative and descriptive study was carried out, in which the students' coats were collected, washed and ironed in a standardized way and wore for four hours in assistance activities. Subsequently, samples from the cuffs were collected with sterile cotton swabs in order to be incubated in order to analyze microbial growth through morphological analysis by Gram's Method and antibiogram. There was bacterial growth of Staphylococcus aureus and Staphylococcus epidermidis in 50% of the collected samples and Staphylococcus aureus, found in patients with wounds in outpatient care, showed resistance to antibiotics such as Vancomycin, Chloramphenicol and Sulfonamides. The data demonstrated that the lab coats wore during assistance activities, even in short periods, are effectively contaminated by strains resistant to antibiotics and can potentially cause infection related to health care.

Objetivó-se evaluar la contaminación bacteriana de batas de laboratorio de estudiantes de enfermería, antes y después del uso en la asistencia a la salud. Realizó-se un estudio cuantitativo y descriptivo, en el que fueron recogidas las batas de los alumnos, lavadas y planchadas de manera estandarizada y usadas durante cuatro horas en actividades de asistencia. Seguidamente, se recolectaron muestras de los puños con hisopos de algodón estéril para ser incubadas; analizando-se posteriormente el crecimiento microbiano mediante análisis morfológico por el método de Gram y el antibiograma. Hubo crecimiento bacteriano de microorganismos Staphylococcus aureus y Staphylococcus epidermidis en 50% de las muestras recolectadas, siendo que el Staphylococcus aureus, hallado en la atención ambulatoria de pacientes con heridas, presentó resistencia a los antibióticos Vancomicina Cloramfenicol y Sulfonamidas. Los datos demostraron que las batas de laboratorio utilizadas durante las actividades de asistencia, incluso en períodos cortos, efectivamente son contaminadas por cepas resistentes a los antibióticos y que potencialmente pueden causar infección relacionada a la asistencia a la salud.

Acute bilateral endophthalmitis following bilateral intravitreal bevacizumab [avastin] injection

The clinical presentation and management of two patients who presented with acute bilateral endophthalmitis following bilateral intravitreal bevacizumab injection. Both cases were diagnosed clinically and subsequent to a vitreous sample, intravitreal ceftazidime [2.25 mg/0.lml] and vancomycin [l mg/0.lml] were injected. One patient had a significant improvement in signs and symptoms after intravitreal antibiotics. However, there were was no improvement in the other patient and pars plana vitrectomy was performed bilaterally. Vitreous cultures were positive in both cases for Staphylococcus epidermidis

A Case of Fulminant Sclerosing Peritonitis Presented Like Acute Culture-Negative Peritonitis and Successfully Treated with Corticosteroid Therapy

Sclerosing peritonitis is an uncommon complication of peritoneal dialysis. It is characterized by peritoneal fibrosis and sclerosis. The most common clinical presentations of sclerosing peritonitis in peritoneal dialysis patients are ultrafiltration failure and small bowel obstruction. The prognosis and response to immunosuppressive therapy of sclerosing peritonitis presenting with ultrafiltration failure or small bowel obstruction are poor. Here, we describe the case of a 28-yr-old man with end-stage renal disease on peritoneal dialysis showing fulminant sclerosing peritonitis presented like acute culture-negative peritonitis and was successfully treated with corticosteroid therapy. It is not well recognized that sclerosing peritonitis may present in this way. The correct diagnosis and corticosteroid therapy may be life-saving in a fulminant form of sclerosing peritonitis.

Molecular & phenotypic characterization of Staphylococcus epidermidis in implant related infections.

Background & objectives: The discrimination between the Staphylococcus epidermidis colonizing the deep seated indwelling devices and those which are mere commensals has always been a challenge for the clinical microbiologist. This study was aimed to characterize the S. epidermidis isolates obtained from device related infection for their phenotypic and molecular markers of virulence and to see whether these markers can be used to differentiate the pathogenic S. epidermidis from the commensals. Methods: Fifty five S. epidermidis isolates from various device related infections such as endophthalmitis following intra-ocular lens (IOL) implantation, intravascular (IV) catheter related sepsis and orthopaedic implant infections, were studied for slime production, biotyping, antibiotic sensitivity; and mec A and ica positivity by the recommended procedures. Results: Twenty three (41.8%) isolates were multi-drug resistant, 26 (65.2%) were slime producers, 30 (54.5%) were adherent, 23 (41.8%) possessed the intercellular adhesin (ica) gene, and 28 (50.9%) harboured the mec A gene. Biotypes I and III were the commonest, most members of which were multi- drug resistant. Twenty two (73.3%) of the 30 adherent bacteria were slime producers as opposed to only 4 (16%) of the 25 non-adherent bacteria (P<0.001). A vast majority i.e. 21 (91.3%) of the 23 ica positive organisms were adherent to artificial surfaces in contrast to only 9 (28.1%) of the 32 non-ica positive organisms (P<0.001). Twenty (86.9%) of the 23 ica positive bacteria were slime producers, as opposed to only 6 (18.7%) of the 32 ica negative bacteria (P<0.001). Of the 23 multi-drug resistant isolates, 19 (82.6%) carried the mec A gene. Interpretation & conclusions: The present findings showed that ica AB and mec A were the two important virulence markers of S. epidermidis in implant infections and slime was responsible for the sessile mode of attachment on the devices.

Conduta em infecções relacionadas a cateter venoso central em um hospital de referência / Care conduct for central venous catheter-related infectionsat an excellence hospital

Objetivos: avaliar a adesão às recomendações para diagnóstico de sepse relacionada a cateter (SRC), verificando a realização simultânea cultura de ponta de cateter (CPC) e hemocultura de sangue periférico (HP), em um hospital de referência. Métodos: trata-se de estudo transversal, realizado no Hospital das Cínicas da Universidade Federal de Minas Gerais, no período de janeiro de 2007 a outubro de 2009. Os dados foram coletados por profissionais especializados da Comissão de Controle de Infecção Hospitalar. Os critérios de base basearam-se nos critérios de notificação do National Healthcare Safety Network e diretrizes da Infectious Diseases Society of America (IDSA). Os dados foram digitados e analisados pelo Statistical Package for the Social Sciences (SPSS) versão 14.0. Resultados: de 683 CPC com crescimento de microrganismos, apenas 220 (32,2%) apresentaram isolamento de microrganismo em HP concomitante. Desses 220 casos, 74,1% apresentaram crescimento do mesmo microrganismo, com mesmo perfil fenotípico, em ambas as amostras. Nos casos de HP com resultado negativo e casos em que a HP não foi realizada, antimicrobianos foram prescritos em 25,7 e 31,5% dos casos, respectivamente, embora não tenha havido critérios para definição de SRC. Conclusão: apenas da recomendação de realização de CPC pareada com HP, este estudo reflete a prática de realização de CPC isolada e pode estar relacionada ao uso inapropriado de antimicrobianos, aumentando custos da assistência e favorecendo a seleção de resistência bacteriana. O diagnóstico e tratamento da SRC devem ser melhorados e os profissionais devem ser conscientizados das práticas adequadas de manejo de cateter venoso central...

Objectives: This study aims to assess compliance with recommendations for the diagnosis of catheter-related bloodstream infection (CRBSI) at an excellence hospital by verifying simultaneous performance of catheter tip culture (CTC) and peripheral blood culture (PBC). Methods: This is a cross-sectional study conducted at UFMG University Hospital from January 2007 through October 2009. Data were collected by specialized professionals of the Hospital Infection Control Committee. The notification criteria followed those prescribed by the National Healthcare Safety Network and the Infectious Diseases Society of America (IDSA). Database and statistical analysis was performed using SPSS (Statistical Package for the Social Sciences) version 14.0. Results: Concurrent peripheral blood culture was performed for only 220 (32.2%) of the 683 CTC samples presenting microorganism growth. This points to low compliance with the existing guidelines. Out of the 220 positive CTC paired with PBC results, 74.1% presented the same microorganism, with the same phenotypic profile in both samples. As for negative PBC results and no blood culture testing, antibiotics were prescribed in 25.7 and 31.5% of the cases respectively, despite the inexistence of criteria to determine CRBSI. Conclusions: Despite recommendations for pairing CTC and PBC results, this study points to the common practice of performing isolated CTC tests. This may lead to inappropriate use of antimicrobials, increasing health care costs and selection of resistant bacteria. CRBSI diagnosis and treatment should be improved, and professionals should be aware of adequate practices and management of central venous catheter...

Farnesol in combination with N-acetylcysteine against Staphylococcus epidermidis planktonic and biofilm cells

Staphylococcus epidermidis is the most frequent cause of nosocomial sepsis and catheter-related infections, in which biofilm formation is considered to be the main virulence mechanism. In biofilm environment, microbes exhibit enhanced resistance to antimicrobial agents. This fact boosted the search of possible alternatives to antibiotics. Farnesol and N-acetylcysteine (NAC) are non-antibiotic drugs that have demonstrated antibacterial properties. In this study, the effect of farnesol and NAC isolated or in combination (farnesol+NAC) was evaluated. NAC at 10 × MIC caused a total cell death in planktonic cells. On the other hand, S. epidermidis biofilms exhibited 4 log reduction in viable cell number after a 24h treatment with NAC at the former concentration. Our results demonstrated that there was a higher CFU log reduction of S. epidermidis planktonic cells when farnesol was combined with NAC at 1 × MIC relatively to each agent alone. However, these results were not relevant because NAC alone at 10 × MIC was always the condition which gave the best results, having a very high killing effect on planktonic cells and a significant bactericidal effect on biofilm cells. This study demonstrated that no synergy was observed between farnesol and NAC. However, the pronounced antibacterial effect of NAC against S. epidermidis, on both lifestyles, indicates the use of NAC as a potential therapeutic agent in alternative to antibiotics.

16S rRNA gene-based identification of bacteria in postoperative endophthalmitis by PCR- Denaturing Gradient Gel Electrophoresis (PCR-DGGE) fingerprinting

Conventional microbiological culture techniques are frequently insufficient to confirm endophthalmitis clinical cases which could require urgent medical attention because it could lead to permanent vision loss. We are proposing PCR-DGGE and 16S rRNA gene libraries as an alternative to improve the detection and identification rate of bacterial species from endophthalmitis cases.

In vitro oxidant effects of D-glucosamine reduce adhesión and biofilm formation of Staphylococcus epidermidis / Los efectos oxidantes de la D-glucosamina in vitro reducen la adhesión y formación de biofilms de Staphylococcus epidermidis

Staphylococcus epidermidis is a common pathogen in medical device-associated infections. Its major pathogenic factor is the ability to form adherent biofilms. In this work, three S. epidermidis strains isolated from infected catheters were chosen with the objective of investigating the effect of D-glucosamine (D-Glu) on reactive oxygen species (ROS) production, adhesion and biofilm formation. The chemiluminescence and nitroblue tetrazolium reduction assays were used to determine ROS production by planktonic S. epidermidis and the microtiter plate assay to quantify in vitro biofilm formation. D-Glu generated a dose-dependent increase in ROS in planktonic cells with maximum stimuli at a concentration of 0.05 mM, and reduced adhesion and biofilm formation. On the other hand, glucose showed an antioxidative stress action and promoted biofilm adhesion and growth. This study suggests a potential application of D-Glu against infections associated with indwelling medical devices, since the oxidative stress caused by this hexosamine in planktonic S. epidermidis contributed to reducing biofilm formation.

Staphylococcus epidermidis es un patógeno común en infecciones asociadas a dispositivos médicos. Su factor de patogenicidad más importante es la capacidad para formar biofilms. Se trabajó con tres cepas de S. epidermidis aisladas de catéteres, con las que se efectuaron ensayos de quimioluminiscencia y de reducción de azul de nitrotetrazolio, para determinar la producción de especies reactivas del oxígeno (ERO) en S. epidermidis planctónico, y ensayos dirigidos a cuantificar la formación de biofilm in vitro, empleando placas multipocillos. La D-glucosamina generó un aumento dependiente de la dosis en la producción de ERO en las células planctónicas, con un estímulo máximo a una concentración de 0,05 mM. Este aumento condμlo a la reducción de la adhesión y de la formación de biofilm. La adición de glucosa, en cambio, mostró un efecto anti estrés oxidativo y promovió la adhesión y el crecimiento de biofilm. Este estudio sugiere una posible aplicación de la D-glucosamina contra las infecciones asociadas a dispositivos médicos, ya que el estrés oxidativo provocado por esta hexosamina contribuyó a una menor formación de biofilm.

Isolation of Staphylococcus epidermidis from inflamed upper respiratory tract of an orange-spined hairy dwarf porcupine (Sphiggurus villosus)

The orange-spined hairy dwarf porcupine (Sphiggurus villosus) is a rodent species common in most parts of South America, and little is known about the pathologies that can afflict it. A specimen was delivered at the Wildlife Research and Medical Center (CEMPAS), School of Veterinary Medicine and Animal Husbandry, UNESP, Botucatu, SP, Brazil. The animal showed intense apathy, with purulent secretion in the nasal cavity and fracture of the lumbar spine. Due to the unfavorable prognosis, the porcupine was euthanized and microbiological culture of nasal discharge showed Staphylococcus epidermidis. The antimicrobial resistance test revealed sensitivity to all tested antimicrobials (ampicillin, oxacillin, tetracycline, penicillin G, neomycin, cephalexin, gentamicin, enrofloxacin, ciprofloxacin, cotrimoxazol, cefoxitin and cephalothin). This bacterium is part of the nasal flora of humans and other animals, and may cause infection under certain conditions. In the present study, the infection and colonization by S. epidermidis was the probable cause of the inflammatory process. The sensitivity to all tested antimicrobials suggests that this strain has not been previously exposed to such drugs.

Comparison of teicoplanin disk diffusion and broth microdilution methods against clinical isolates of Staphylococcus aureus and S. epidermidis

The CLSI M100-S19 document has recommended the disuse of vancomycin disks for staphylococci and informed that studies on the action of teicoplanin in disk-diffusion testing should be performed. We describe the comparison of two methods, disk diffusion and broth microdilution, for determining teicoplanin susceptibility in clinical isolates of staphylococci. Overall results showed an aggregation rate of 96.8 percent; Staphylococcus aureus showed total agreement while S. epidermidis showed 93.8 percent of agreement. According to these local results, disk diffusion can still be employed to teicoplanin susceptibility determination for staphylococci in our institution.

Antibiofilm activity of Cobetia marina filtrate upon Staphylococcus epidermidis catheter-related isolates

We report the antibiofilm activity by the sponge-associated bacterium Cobetia marina upon Staphylococcus epidermidis clinical isolates obtained from central venous catheters. Antibiofilm activity/antimicrobial susceptibility correlation might predict the action of the metabolite(s) upon Staphylococcus epidermidis in the clinic, making it a possible adjuvant in therapies against biofilm-associated infections.