Coagulase-negative staphylococci isolates from blood cultures of newborns in a tertiary hospital in southern Brazil

Abstract Neonatal sepsis continues to be a major cause of morbidity and mortality worldwide. Coagulase-negative staphylococci (CoNS), commonly found on the skin, being the main agents isolated. The aim of this study was to evaluate CoNS isolated from blood cultures of newborn (NB) infants. The study took place between 2014 and 2016/2017 in a tertiary hospital in southern Brazil. Using the VITEK 2 system (bioMérieux, Marcy l'Etoile, France), the microorganisms were identified and had their sensitivity profiles determined. The minimum inhibitory concentrations of linezolid, tigecycline, and vancomycin were also determined. The clinical parameters and mortality rates of NBs were evaluated. From January to December 2014, 176 CoNS isolates were obtained from 131 patients and from June 2016 to July 2017, 120 CoNS isolates were obtained from 79 patients. Staphylococcus epidermidis was most prevalent in both periods. Resistance rates increased between 2014 and 2016/2017, especially against ciprofloxacin (52.27% and 73.11%, p = 0.0004), erythromycin (51.40% and 68.07%, p = 0.0054), gentamicin (50.59% and 67.23%, p = 0.0052), and penicillin (71.3% and 99.17%, p = 0.0001), respectively. With 100% susceptibility to linezolid, tigecycline, and vancomycin in both periods and methodologies tested. In 2014, 53.44% of the NBs received antibiotic therapy, and of these, 77.14% used a catheter; in 2016/2017, these were 78.48% and 95.16%, respectively. Regarding laboratory tests, a hemogram was ineffective, since patients with sepsis presented normal reference values. In 2014 and 2016/17, 15.71% and 17.74% of the NBs died, respectively. S. epidermidis was the predominant microorganism, related to catheter use in most cases. The resistance rates have increased over time, demonstrating the importance of adopting control and prevention measures in this hospital. CoNS are responsible for a significant neonatal sepsis mortality rate in infants.

Stress conditions in the host induce persister cells and influence biofilm formation by Staphylococcus epidermidis RP62A

Abstract INTRODUCTION: Studies have demonstrated that pathogens react to the harsh conditions in human tissues by inducing mechanisms that promote survival. METHODS: Persistence and biofilm-forming ability were evaluated during stress conditions that mimic those in the host. RESULTS: Carbon-source availability had a positive effect on Staphylococcus epidermidis RP62A adhesion during hypoxia, accompanied by a decrease in pH. In contrast, iron limitation led to decreased surface-adherent biomass, accompanied by an increase medium acidification and lactate levels. Interestingly, iron starvation and hypoxia induced persister cells in planktonic culture. CONCLUSIONS: These findings highlight the role of host stress in the virulence of S. epidermidis.

Mecanismos de adesão bacteriana aos biomateriais / Mechanisms of bacterial adhesion to biomaterials

A adesão bacteriana aos biomateriais é processo de alta complexidade que demanda importante preocupação médica dada a sua evidente influência sobre a morbimortalidade dos pacientes que fazem uso de próteses, além dos vultosos gastos que o envolvem. Nesta revisão com base na literatura médica são apresentados os principais microrganismos envolvidos na adesão aos biomateriais, discutindo a patogênese desseprocesso, sendo abordada cada uma de suas etapas, inclusive a formação do biofilme, que é etapa ímpar para o estabelecimento da infecção. São indicados, também, os principais fatores que influenciam o mecanismo de adesão, incluindo as características bacterianas e dos materiais, assim como as propriedades do meio.

Bacterial adhesion to biomaterials is a highly complex process that warrants careful medical scrutiny given not only its obvious influence on morbidity and mortality of patients who use dentures, but also the substantial costs involved. In this literature-based review we present the main microorganisms involved in adhesion to biomaterials and discuss the pathogenesis involved, addressing each of its stages, including biofilm formation, which is a crucial step in the the establishment of infection. We also highlight the main factors influencing the adhesion mechanism, including bacterial, materials and medium properties.

Traumatic endophthalmitis presenting as isolated retinal vasculitis and white-centered hemorrhages: Case report and review of literature.

The article reports a case and review of the literature of endophthalmitis presenting as isolated retinal vasculitis. A 26-year-old male was observed to have white-centered retinal hemorrhages and retinal vasculitis following an occult scleral perforation. At presentation, the visual acuity was 20/60. With clinical suspicion of early endophthalmitis, he underwent wound exploration, scleral tear repair, vitreous biopsy and administration of intravitreal antibiotics. Microbiology evaluation revealed significant presence of methicillin-resistant coagulase-negative Staphylococcus epidermidis. Final visual acuity improved to 20/20 at 6 weeks postoperatively. Literature search revealed eight similar cases, all of them due to Staphylococcus species. Retinal vasculitis and white-centered retinal hemorrhages can be a presenting sign of early endophthalmitis, especially with non-fulminant pathogens like S. epidermidis.

Intravenous device associated blood stream staphylococcal infection in paediatric patients.

Background & objectives: Intravenous device (IVD) associated nosocomial blood stream infections due to staphylococci are major cause of morbidity and mortality. The present study was carried out to assess the frequency of staphylococcal IVD associated infections in a paediatric ward of a tertiary case hospital. Prevalence of resistance to commonly used antimicrobials in hospital acquired staphylococcal isolates was also tested. Methods: Children admitted in paediatric wards with IVD for more than 48 h were enrolled. Blood, IVD tip at the time of removal, skin swab at the site of insertion of IVD and nasal swab were collected and cultured by standard protocol. All staphylococcal isolates from any source were analyzed for antimicrobial susceptibility by disk diffusion method. Genotyping matching of those staphylococcal isolates was done which were isolated from different sites of the same patient, but were phonotypically similar. Genotype of blood isolate was compared with genotype of isolate from nose/IVD/skin. Results: Staphylococcus aureus was the most frequent blood isolate (8.7%) followed by Candida (2.9%), coagulase negative staphylococci (CoNS 2.6%), Pseudomonas spp. (0.4%), Klebsiella spp. (0.3%) and Escherichia coli (0.1%). Isolation of microorganisms from blood was significantly higher in patients whose skin, IVD and nose were colonized by same microorganism (P<0.001). None of the staphylococcal isolate was found to be resistant to glycopeptides (vancomycin and teicoplanin). High penicillin and oxacillin resistance was present in both S. aureus (penicillin resistance; 76.8%, oxacillin resistance; 66.7%) and CoNS (penicillin resistance; 73.3%, oxacillin resistance; 60.0%). Among CoNS biotypes, S. haemolyticus was commonest blood isolate while S. epidermidis was commonest isolate from Skin/nose. Only 33.3 per cent of S. aureus blood stream infections and most of S. epidermidis and S. haemolyticus blood infections were IVD associated. Interpretation & conclusions: Staphylococci were the major causative agent of nosocomial blood stream infections. All episodes of septicaemia due to S. epidermidis and S. haemolyticus were IVD associated while only 1/3 of S. aureus septicaemia was IVD associated.

Changing patterns of blood borne sepsis in special care baby unit, Khoula Hospital

Infection is a frequent and important cause of morbidity and mortality in neonatal units all over the world. Over the years, there has been a shift in the microorganisms responsible for neonatal septicemia. This study aims to analyze the changing patterns of blood borne organisms in the neonatal unit. This retrospective study was undertaken at the neonatal intensive care unit of Khoula Hospital in Muscat, Sultanate of Oman to analyze the incidence of blood borne sepsis and its changing pattern from 1997-2000. Out of a total 2181 admissions to the neonatal intensive care unit, 71 [3.25%] babies had positive blood culture. A reduction in the incidence of blood borne sepsis with changing patterns of organisms was seen over the period of four years with incidence of Group B Streptococcus declining from 34% in 1997-1998 to 17.8% in 1999-2000 and the incidence of CONS [Staphylococcus epidermidis] increasing from 20% in 1997-1998 to 35% in 1999-2000. Overall, due to survival and prolonged hospitalization of extremely low birth weight babies who need frequent invasive procedures, and the use of powerful antibiotics, the incidence of Staphylococcus epidermidis which was previously thought to be non pathogenic has increased over the years in neonatal intensive care units

Detecção da produção de slime por estafilococos coagulase-negativa isolados de cateter venoso central / Detection of slime production by coagulase-negative staphylococci isolated from central venous catheter

A produção de slime é um importante fator de virulência dos estafilococos coagulase-negativa, permitindo-lhes aderir sobre as superfícies lisas de biomateriais, e por isso, é associada aos processos de infecção de implantes. No presente estudo a produção de slime em 27 cepas de estafilococos coagulase-negativa foi investigada por cultura em ágar vermelho Congo (77,7% de positividade), método espectrofotométrico ou damicroplaca (81,4% de positividade) e microscopia eletrônica de varredura (88,9% de positividade). Foi também avaliada a resistência de estafilococos coagula-se negativa a vários antimicrobianos usando a técnica do disco difusão. A porcentagem de resistência à penicilina G, oxacilina, eritromicina, clindamicina e gentamicinaem estafilococos produtores de slime foi respectivamente de 88,9%; 70,4%; 81,5%; 66,7% e 59,2%; todos os estafilococos coagulase-negativa foram vancomicina sensíveis. As cepas isoladas de cateter venoso central foram identificadas por método convencional e sistema API Staph. Os 27 estafilococos coagulase-negativa foram identificados como: S. saprophyticus (3,7%), S. xylosus(7,4%), S. haemolyticus (14,8%), S. epidermidis (37,0%), S. warneri (14,8%), S. lugdunensis (7,4%), S. hominis (7,4%), S. schleiferi (3,7%) e S. chromogenes (3,7%). Pode-se concluir que entre a maioria das espécies Staphylococcus coagulase-negativa houve associação entre a produção de slime, origem nosocomial das cepase reduzida sensibilidade aos antimicrobianos, sugerindo potencial patogênico no ambiente hospitalar.

Slime production is an important virulence factor of coagulase-negative Staphylococcus spp., allowing them to attach to smooth surfaces of biomaterials, and it has been associated with infections of implanted medical devices. In the present study the production of slime capsules in 27 strains of coagulase-negative Staphylococcus was investigated by culture in Congo Red agar (77.7% positivity), spectrophotometric or microplate method (81.4% positivity) and scanning electron microscopy (88.9% positivity). The resistance of coagulase-negative strains of Staphylococcus to various antimicrobial agents was also determined by agar disk diffusion. The proportion of strains resistant to penicillin G, oxacillin, erythromycin, clindamycin and gentamicin among the slime-producing staphylococci was 88.9%, 70.4%, 81.5%, 66.7% and 59.2%, respectively; all of the coagulase-negative staphylococci were susceptible to vancomycin. The strains isolated from central venous catheters were identified by a conventional method and the API Staph system. The 27 coagulase-negative taphylococcus strains were identified as: S. saprophyticus (3.7%), S. xylosus (7.4%), S. haemolyticus (14.8%), S. epidermidis (37.0%), S. warneri (14.8%), S. lugdunensis (7.4%), S. hominis (7.4%), S. schleiferi (3.7%) and S. chromogenes (3.7%). It can be concluded that in the most of the coagulase-negative Staphylococcus species there was an association between slime production, the nosocomial origin of the strains and reduced sensitivity to the antibiotics, suggesting a pathogenic potential in the hospital environment.

Identificación de stapylococcus coagulasa negativa aislados del hombre en la ciudad de Valdivia, Chile / Identification of coagulase negative staphylococci from man in Valdivia, Chile

Actualmente , se reconocen 32 especies de Staphylococcus y 8 variedades. La mitad se aisla del hombre, siendo su hábitat el ecosistema cutáneo. Muchas de estas especies son reportadas, produciendo diferentes cuadros, sea por su capacidad de adhesión, como también por los factores predisponentes del huésped y multirresistencia. Poca es la información, al respecto, en Chile. Se identificaron 106 de Staphylococcus coagulasa negativa (SNC), correspondio el 57,5 por ciento a S. epidermidis, el 11,3 por ciento a S. lugdunesis, 6,6 por ciento a S. saprophyticus. Se aisló también S. auricularis, S. cohnii, S. capitis ssp. ureolyticus, S. schleiferi y S. simulans. Se insiste en la correcta identificación de las especies. Los esquemas en uso conducen a error

Septicemia neonatal: incidencia, letalidad y características bacteriológicas: comparación de dos períodos / Neonatal septicemia: incidence, mortality and microbiological findings along 2 different periods

Objetivos: describir y comparar la incidencia y letalidad de la septicemia neonatal, en dos períodos en un hospital universitario. Pacientes y método: se compararon recién nacidos que tuvieron septicemia entre los meses de julio de 1987 a junio de 1989 con los del período de enero de 1995 a diciembre de 1996. Resultados: la incidencia de septicemia neonatal aumentó (2,9 a 8,7 por mil) y la letalidad (44 por ciento a 2,2 por ciento) disminuyó en el segundo período. Las poblaciones estudiadas y los métodos de diagnóstico fueron similares. En las septicemias connatales el germen preponderante fue el Streptococcus grupo B sin diferencias entre períodos (50 por ciento ante 52 por ciento). Entre las septicemias nosocomiales, aumentaron las producidas por estafilococo (desde 25 por ciento a 91 por ciento), siendo Staphylococcus epidermidis devino el principal agente durante el segundo período (57 por ciento del total), disminuyendo la sensibilidad a cloxacilina (100 por ciento a 33 por ciento). Conclusiones: se demuestra un aumento de la incidencia y mejoría del pronóstico de las septicemias neonatales con un cambio en sus características bacteriológicas entre los períodos estudiados, similar a lo observado en otros países

Infecciones de las derivativas del líquido cefalorraquídeo (LCR) / Cerebrospinal fluid shunt infections

Existe una disminución en la incidencia de infecciones de las derivativas asociadas con la instalación de válvulas en los últimos 20 años, probablemente por la mejoría de la técnica quirúrgica y de los materiales de confección. Sin embargo la infección permanece como un riesgo importante en la instalación de estas prótesis. La mayoría de las infecciones son secundarias a cocos gram positivo, especialmente estafilococo epidermidis, y se presentan frecuentemente a las pocas semanas o meses luego de la instalación. La presentación clínica puede ser muy variable, dependiendo de la naturaleza de las derivativas, la edad y las condiciones del paciente y el germen infectante. El diagnóstico y el tratamiento adecuado dependen de la demostración del germen, el cual es frecuentemente cultivado de las mismas derivativas. Generalmente el tratamiento efectivo requiere de la extracción de la derivativa infectada asociado a un tratamiento antimicrobiano adecuado. No se ha demostrado la eficacia de los antibióticos profilácticos en forma categórica. La tasa de infecciones postoperatorias se puede disminuir con un esfuerzo continuo. Las diferencias de las tasas reflejan las diferencias de los métodos de detección de las infecciones. Esto muestra la conveniencia de un comité de vigilancia, pues los reportes rutinarios tienden a disminuir los informes de las infecciones en el tiempo y lo importante no es la comparación con otros hospitales sino detectar los cambios dentro del propio hospital

Conjuntivitis por Chlamydia Trachomatis en recien nacidos y lactantes / Conjunctivitis by Chlamydia Trachomatis in new born and infant

Estudiamos 50 ninos con conjuntivitis clinica. En 6 (12%) se detecto Chlamydia Trachomatis, mediante inmunofluorescencia directa con anticuerpos monoclonales, con asociacion de bacterias en dos casos. De los 44 restantes, en 26 se cultivaron bacterias que se observaron en el gram del exudado como S. epidermidis, S. aureus, E. coli, S. pneumoniae, K. pneumoniae y H. influenzae

Estudio bacteriologico del liquido amniotico durante el embarazo y parto / Amniotic fluid bacteriological study during pregnancy and delivery

Se estudiaron 220 muestras del liquido amniotico, obtenidas en condiciones esteriles y sembradas en medios de cultivos aerobico y unos pocos casos en anaerobico: al mismo tiempo se hacia extendido en coloracion de Gram. El primer grupo de 110 muestras fueron tomadas durante la operacion cesarea: 68 casos sin trabajo de parto de los cuales 64 con membrana integras, y 4 con membranas rotas de mas de 6 horas; la contaminacion bacteriana del liquido amniotico fue detectada en el 12.5% en los casos de membranas integras y en 50% en los casos de membranas rotas. Los 42 casos restantes eran de mas de 12 horas de trabajo de parto y con membranas rotas; la contaminacion del liquido amniotico fue detectada en el 26.5%. Se examinaron 85 placentas y se encontro placentitis leve en un 2.35%, placentitis severa en 1.1% y placentitis moderada en 4.7%. El segundo grupo de 110 muestras fueron tomadas al final de la primera etapa del parto encontrandose una contaminacion bacteriana en un 20%. Los microorganismos aislados del liquido amniotico fueron los siguientes: Estafilococo epidermidis, E. coli y Estreptococo viridans. Es bueno anotar que del primer grupo solo se registro contaminacion del liquido amniotico en un 12.5% en cesarea electiva con membranas integras; y en el segundo grupo en trabajo de parto y membranas integras la contaminacion del liquido amniotico fue de un 20%. La incidencia total de contaminacion del liquido amniotico en el primer grupo fue de un 20.9% y en el segundo grupo de un 20%. El indice de contaminacion en en liquido amniotico en el total de ..