Dynamics of the seasonal airborne propagation of Staphylococcus aureus in academic dental clinics

Abstract Objective Staphylococcus aureus strains can be disseminated during dental treatments and occasionally lead to the contamination and infection of patients and dentists, which is an important public health problem. The dynamics of the airborne propagation and the genetic diversity of S. aureus isolated in an academic dental clinic environment were investigated using isoenzyme typing. Material and Methods The isoenzymes of 44 previously reported isolates were obtained from fresh cultures and extracted using glass beads. Nine isoenzymes were investigated using multilocus enzyme electrophoresis (MLEE). The genetic diversity and relationship among the strains (electrophoretic type - ET) were determined using statistics previously described by Nei25 (1972) and the SAHN grouping method (UPGMA algorithm). Results Clonal pattern analyses indicated a high level of genetic polymorphism occurring among the 33 ETs, which were grouped into five taxa. Each taxon presented one or more clusters that were moderately related and that contained two or more identical/highly related isolates, revealing seasonal airborne propagation in these dental clinic environments. Conclusions These data suggest the occurrence of active microevolutionary processes in S. aureus as well as the possibility of environmental propagation during a 14-month time span. Such findings are important to show that multiuser academic dental clinics can retain certain strains that are spreadable to different niches.

Novel nonsense mutation in the katA gene of a catalase-negative Staphylococcus aureus strain

Abstract We report the first description of a rare catalase-negative strain of Staphylococcus aureus in Chile. This new variant was isolated from blood and synovial tissue samples of a pediatric patient. Sequencing analysis revealed that this catalase-negative strain is related to ST10 strain, which has earlier been described in relation to S. aureus carriers. Interestingly, sequence analysis of the catalase gene katA revealed presence of a novel nonsense mutation that causes premature translational truncation of the C-terminus of the enzyme leading to a loss of 222 amino acids. Our study suggests that loss of catalase activity in this rare catalase-negative Chilean strain is due to this novel nonsense mutation in the katA gene, which truncates the enzyme to just 283 amino acids.

Influence of carvacrol and thymol on the physiological attributes, enterotoxin production and surface characteristics of Staphylococcus aureus strains isolated from foods

This study evaluated the influence of the phenolic compounds carvacrol (CAR) and thymol (THY) on some physiological characteristics and on the modulation of the secretion of some staphylococcal virulence factors, that is, coagulase and enterotoxin. This study also investigated possible mechanisms for the establishment of the anti-staphylococcal activity of these compounds. Sublethal concentrations (0.3 and 0.15 µL/mL) of CAR and THY inhibited the activity of the enzymes coagulase and lipase and led to a decrease in salt tolerance. At the tested sublethal concentrations, both CAR and THY led to a total suppression of enterotoxin production. The loss of a 260-nm-absorbing material and an efflux of potassium ions occurred immediately after the addition of CAR and THY at 0.6 and 1.2 µL/mL and increased up to 120 min of exposure. Electron microscopy of cells exposed to CAR and THY (0.6 µL/mL) revealed that individual cells appeared to be deformed, with projections of cellular material. The observations of leakage of cellular material and an altered cell surface suggest that gross damage to a cell's cytoplasmic membrane, which results in a disruption in protein secretion, could be responsible for the anti-staphylococcal properties of CAR and THY.

Enterotoxigenicity of Staphylococcus aureus isolated from traditional and commercial dairy products marketed in Iran

This study was conducted to determine the prevalence rate, enterotoxigenecity, and antimicrobial resistance of S. aureus isolated from dairy products in Iran. From September 2010 to July 2011, a total of 347 samples from various dairy products, traditional and commercial, were collected from randomly selected retail stores. Overall, 20 samples (5.8%) were found to be contaminated with S. aureus. The highest prevalence of S. aureus was found in traditional cheese (11.1%), followed by traditional ice-cream (5.9%), cream (5.6%), and butter (5.3%). The ability to synthesize classical staphylococcal enterotoxins (SEA-E) was determined in 7 of 20 (35%) isolates by using ELISA. SE type C was the most common enterotoxin found in the isolated S. aureus (42.9%), followed by SE type A (28.6%), SEA+SEC and SE type D (14.3%). Of the 20 isolates, 16 (80.0%) were positive for one or more entrotoxin genes and 8 different genotypes were observed. Susceptibilities of the isolates were determined for 14 antimicrobial drugs using the disk diffusion assay. Most of the isolates (95.0%) were resistant to one or more two antimicrobial agent and 45.0% of the isolates were resistant to three or more of drugs. Resistance to ampicillin was the most common finding (55.0%), followed by tetracycline (40.0%) and penicillin G (30.0%). The results of this study showed the wide spread of enterotoxigenic and multidrug-resistant S. aureus strains in traditional dairy products in Iran and highlighted their public health hazards.

Inhibitory effect of black and red pepper and thyme extracts and essential oils on enterohemorrhagic Escherichia coli and DNase activity of Staphylococcus aureus

In this study, extracts and essential oils of Black and Red pepper and Thyme were tested for antibacterial activity against Escherichia coli O157:H7 and Staphylococcus aureus. Black and Red pepper and Thyme were provided from Iranian agricultural researches center. 2 g of each plant powder was added to 10 cc ethanol 96 degrees. After 24 h, the crude extract was separated as an alcoholic extract and concentrated by distillation method. Plants were examined for determining their major component and essential oils were separated. Phytochemical analyses were done for detection of some effective substances in extracts. The antibacterial activity against. Escherichia coli O157:H7 and Staphylococcus aureus was tested and the results showed that all extracts and essential oils were effective and essential oils were more active. The extracts and oils that showed antimicrobial activity were later tested to determine the Minimum Inhibitory Dilution [MID] for those bacteria. They were also effective on the inhibition of DNase activity. This study was indicated that extracts and essential oils of Black and Red pepper and Thyme can play a significant role in inhibition of Escherichia coli O157:H7 and Staphylococcus aureus

Prevalence of resistance phenotypes in Staphylococcus aureus and coagulase-negative isolates of venous ulcers of primary healthcare patients / Prevalência de fenótipos de resistência em Staphylococcus aureus e coagulase negativos isolados de úlceras venosas de pessoas atendidas na atenção primária

INTRODUCTION: In venous ulcers, the presence of Staphylococcus aureus and coagulase-negative staphylococcus resistance phenotypes can aggravate and limit the choices for treatment. METHODS: Staphylococcus isolated from 69 patients (98 ulcers) between October of 2009 and October of 2010 were tested. The macrolide, lincosamide, streptogramin B (MLS B) group resistance phenotype detection was performed using the D-test. Isolates resistant to cefoxitin and/or oxacillin (disk-diffusion) were subjected to the confirmatory test to detect minimum inhibitory concentration (MIC), using oxacillin strips (E-test®). RESULTS: The prevalence of S. aureus was 83%, and 15% of coagulase-negative staphylococcus (CoNS). In addition were detected 28% of methicillin-resistant Staphylococcus aureus (MRSA) and 47% of methicillin-resistant coagulase-negative staphylococcus (MRCoNS). Among the S. aureus, 69.6% were resistant to erythromycin, 69.6% to clindamycin, 69.6% to gentamicin, and 100% to ciprofloxacin. Considering the MRSA, 74% were highly resistant to oxacillin, MIC ≥ 256µg/mL, and the MLS Bc constitutive resistance predominated in 65.2%. Among the 20 isolates sensitive to clindamycin, 12 presented an inducible MLS B phenotype. Of the MRCoNS, 71.4%were resistant to erythromycin, ciprofloxacin and gentamicin. Considering the isolates positive for β-lactamases, the MIC breakpoint was between 0.5 and 2µg/mL. CONCLUSIONS: The results point to a high occurrence of multi-drug resistant bacteria in venous ulcers in primary healthcare patients, thus evidencing the need for preventive measures to avoid outbreaks caused by multi-drug resistant pathogens, and the importance of healthcare professionals being able to identifying colonized versus infected venous ulcers as an essential criteria to implementing systemic antibacterial therapy.

INTRODUÇÃO: Em úlceras venosas, a presença de Staphylococcus aureus e coagulase negativo com fenótipos de resistência pode constituir fator agravante e limita as opções terapêuticas. MÉTODOS: Foram avaliados estafilococos isolados de 69 pacientes, representando 98 úlceras no período de outubro de 2009 a outubro de 2010. A detecção fenotípica da resistência ao grupo macrolide, lincosamide, streptogramin B (MLS B) foi realizada pelo D-test. Isolados resistentes a cefoxitina e/ou oxacilina (disco-difusão) foram submetidos ao teste confirmatório para detecção da minimum inhibitory concentration (MIC), empregando fitas de oxacilina (E-test®). RESULTADOS: A prevalência de S. aureus foi de 83% e de 15% de coagulase-negative staphylococcus (CoNS). Identificou-se 28% de methicillin-resistant Staphylococcus aureus (MRSA) e 47% de methicillin-resistant coagulase-negative staphylococcus (MRCoNS). Entre o S. aureus, 69,6% apresentaram resistência a eritromicina, 69,6% a clindamicina, 69,6% a gentamicina e 100% a ciprofloxacina. Setenta e quatro por cento dos MRSA apresentaram elevado nível de resistência a oxacilina, MIC ≥ 256µg/mL, e em 65,2% predominou a resistência constitutiva MLS Bc. Dos 20 isolados sensíveis a clindamicina, 12 apresentaram fenótipo MLS B induzível. Um total de 71,4% dos MRCoNS apresentaram resistência a eritromicina, ciprofloxacina e gentamicina. Dos isolados positivos para a enzima β-lactamases, as MIC tiveram breakpoint entre 0,5 a 2µg/mL. CONCLUSÕES: Os resultados sinalizam elevada ocorrência de bactérias multirresistentes em úlceras venosas de pacientes recebendo atenção primária, evidenciando a necessidade de medidas preventivas que evitem surtos causados por patógenos resistentes a múltiplas drogas e a importância dos profissionais em discernir infecção de colonização em úlcera venosa, critério fundamental na indicação antibioticoterapia sistêmica.

Capacidad de los laboratorios nacionales de referencia en Latinoamérica para detectar mecanismos de resistencia emergentes / Capability of national reference laboratories in Latin America to detect emerging resistance mechanisms

Objetivo. Evaluar la capacidad de 17 laboratorios nacionales de referencia que participan en el Programa Latinoamericano de Control de Calidad en Bacteriología y Resistencia a los Antimicrobianos (LA-EQAS) para detectar mecanismos de resistencia emergentes, a saber: resistencia de enterobacterias a carbapenemes por presencia de Klebsiella pneumoniae carbapenemasa (KPC); resistencia de enterobacterias a carbapenemes por presencia de metalobetalactamasas (MBL) tipo IMP, y resistencia intermedia a vancomicina de aislamientos de Staphylococcus aureus (VISA). Métodos. Se enviaron los siguientes tres aislamientos a los 17 laboratorios participantes del LA-EQAS: Klebsiella pneumoniae OPS-161 productor de KPC, Enterobacter cloacae OPS-166 productor de IMP y S. aureus OPS-165 con resistencia intermedia a vancomicina. Se evaluó la interpretación de las pruebas de sensibilidad y detección del mecanismo de resistencia y el tamaño de los halos de inhibición (método de difusión por discos) o valor de la concentración inhibitoria mínima (CIM). Resultados. La concordancia en la detección de los mecanismos de resistencia fue de 76,4%, 73,3% y 66,7% con respecto a la cepas K. pneumoniae OPS-161, E. cloacae OPS-166 y S. aureus OPS-165, respectivamente. La concordancia entre las zonas de inhibición obtenidas por los laboratorios participantes y los rangos establecidos por el laboratorio coordinador fue aceptable en los tres aislamientos, ya que alcanzó 90,8%, 92,8% y 88,9%, respectivamente, para cada cepa. Conclusiones. La concordancia global en la detección de los mecanismos de resistencia KPC, MBL y VISA fue de 72,1%. Consideramos que los laboratorios nacionales de referencia de América Latina son capaces de reconocer estos mecanismos de resistencia emergentes y se espera que en el futuro la concordancia alcance su nivel máximo.

Objective. To evaluate the capability of 17 national reference laboratories participating in the Latin American Quality Control Program in Bacteriology and Antibiotic Resistance (LA-EQAS) to detect emerging resistance mechanisms— namely: resistance of enterobacteria to carbapenems due to the presence of Klebsiella pneumoniae carbapenemase (KPC) and metallo-beta-lactamase (MBL) type IMP, and intermediate resistance of Staphylococcus aureus isolates to vancomycin (vancomycinintermediate resistant S. aureus—VISA). Methods. The following three isolates were sent to the 17 participating LA-EQAS laboratories: KPC-producing Klebsiella pneumoniae PAHO-161, IMP-producing Enterobacter cloacae PAHO-166, and S. aureus PAHO-165 with intermediate resistance to vancomycin. Performance of each of the following operations was evaluated: interpretation of sensitivity tests, detection of the resistance mechanism, and assessment of either inhibition halo size (disk diffusion method) or minimum inhibitory concentration (MIC). Results. Concordance in the detection of resistance mechanisms was 76.4%, 73.3%, and 66.7% for the K. pneumoniae PAHO-161, E. cloacae PAHO-166, and S. aureus PAHO- 165 strains, respectively. Concordance between the inhibition areas observed by the participating laboratories and the ranges established by the coordinating laboratory was acceptable for all three isolates, at 90.8%, 92.8%, and 88.9%, respectively. Conclusions. Overall concordance in on the detection of KPC, MBL, and VISA resistance mechanisms was 72.1%. We consider the national reference laboratories in Latin America capable of recognizing these emerging resistance mechanisms and expect that maximum levels of concordance will be reached in the future.

Epidemiology and antimicrobial resistance of staphylococci isolated from different infectious diseases

A total of 187 isolates from 470 clinical specimens were collected from three hospitals in El-Minia governorate and identified as 132 Staphylococcus aureus strains and 55 coagulase-negative staphylococci (CoNS) strains. Susceptibility of isolates to antimicrobial agents was tested by the agar dilution method. The isolated S. aureus strains showed low resistance to vancomycin (1.5 percent), amikacin (2.3 percent) and gatifloxacin (3.8 percent). Vancomycin was the most effective antibiotic against CoNS. The ampicillin-resistant isolates were tested for â-lactamase production where, 61.7 percent of S. aureus and 42.9 percent of CoNS were positive for â-lactamase enzyme. Beta-lactamase producing strains were screened for their plasmid profile using alkaline lysis method. Some of these strains carried at least one plasmid suggesting plasmid-mediated antibiotic resistance. When cells of these strains were exposed to curing agent ethidium bromide, the production of the â-lactamase was lost. Resistance by efflux was studied by a modified fluorometric assay. Addition of uncoupler carbonyl cyanide m-chlorophenylhydrazone (CCCP) increased norfloxacin accumulation in quinolone resistant S. aureus strains, suggesting endogenous energy-dependent efflux. Combinations of ciprofloxacin with four antimicrobial agents against methicillin resistant S.aureus (MRSA) strains were investigated using decimal assay for additivity (DAA) technique. Synergistic interaction was observed between ciprofloxacin and oxacillin. ciprofloxacin plus cefepime and gentamicin appeared to be additive, while ciprofloxacin plus erythromycin was antagonistic.

Coagulase-Positive Staphylococcal Necrotizing Fasciitis Subsequent to Shoulder Sprain in a Healthy Woman

Necrotizing fasciitis (NF) is a deep infection of the subcutaneous tissue that progressively destroys fascia and fat; it is associated with systemic toxicity, a fulminant course, and high mortality. NF most frequently develops from trauma that compromises skin integrity, and is more common in patients with predisposing medical conditions such as diabetes mellitus, atherosclerosis, alcoholism, renal disease, liver disease, immunosuppression, malignancy, or corticosteroid use. Most often, NF is caused by polymicrobial pathogens including aerobic and anaerobic bacteria. NF caused by Staphylococcus aureus as a single pathogen, however, is rare. Here we report a case of NF that developed in a healthy woman after an isolated shoulder sprain that occurred without breaking a skin barrier, and was caused by Staphylococcus aureus as a single pathogen.

Microbiota conjuntival e resistência a antibióticos em recém-nascidos prematuros internados em unidade de terapia intensiva / Conjunctival microbiota and antibiotics resistance in preterm newborns hospitalized in neonatal intensive care unit

OBJETIVO: Analisar a flora bacteriana da conjuntiva e o padrão de resistência a antibióticos em crianças recém-nascidas prematuras na Unidade de Terapia Intensiva Neonatal (UTIN) do Hospital das Clínicas da Universidade Federal de Pernambuco (UFPE). MÉTODOS: Foram analisadas amostras de secreção conjuntival de 48 recém-nascidos com permanência de pelo menos 48 horas na UTIN. RESULTADOS: Das 48 amostras 40 (83,3 por cento) apresentaram cultura positiva, com maior frequência de Staphyloccocus coagulase-negativo (43,2 por cento) e Staphyloccocus aureus (25,0 por cento). Foram consideradas multirresistentes 63,9 por cento das bactérias. Os antibióticos com maior sensibilidade no antibiograma foram gatifloxacino (97,2 por cento), vancomicina (94,4 por cento) e ofloxacino (94,4 por cento). CONCLUSÕES: A flora bacteriana da conjuntiva de prematuros na UTIN é diversificada, predominando as bactérias Gram-positivas, geralmente multirresistente a antibióticos.

PURPOSE: To analyze the conjunctival bacterial flora and the antibiotics resistance pattern in preterm newborns at the Neonatal Intensive Care Unit (NICU), in "Hospital das Clínicas da Universidade Federal de Pernambuco - UFPE". METHODS: Material from the conjunctival sac was obtained from 48 premature infants eyes that stayed at in NICU more than 48 hours. RESULTS: Culture analysis revealed that 40 (83.3 percent) were positive and the pathogens most commonly isolated included Coagulase-negative Staphylococcus (43.2 percent) and Staphylococcus aureus (25.0 percent), being 63.9 percent of the bacteria multiresistant. Antimicrobial test results demonstrated great sensitivity to gatifloxacin (97.2 percent), vancomycin (94.4 percent) and ofloxacin (94.4 percent). CONCLUSIONS: Conjunctival bacterial flora among newborns in NICU is varied, mainly Gram-positive, usually multiresistant to antibiotics.

Prevalence and B-lactamase producing bacterial isolates in a teaching hospital in Peshawar, Pakistan: a four year study

Prevalence of microorganisms was studies in clinical samples of various body fluids [n=12259], collected from patients at Post graduate Medical Institute Hayatabad Medical Complex [PGMI, HMC] Peshawar. Only 34.90% of samples exhibited growth, 36.25% of these isolates were Gram positive and 63.75% were Gram negative bacteria. E. coli was the most prevalent organism [39.45%] followed by S. aureus [32.23%], Proteus spp. [9.23%], Pseudomonas spp. [6.54%], Streptococuss spp. [3.51%], Acinetobacter spp. [2.66%], Citrobacter spp. [2.8%], Providencia spp. [2.2%] and miscellaneous bacteria [1.38%]. The growth of bacteria was high in pus samples [44.03%] followed by urine [38.21%], high vaginal swab [HVS] [8.58%], cerebrospinal fluid [CSF] [1.96%], blood [3.39%] and miscellaneous samples [3.83%]. E. coli and S. aureus were the most prevalent organism in urine [56.57%] and pus samples [44.02%], respectively. The frequency of E. coli [61.76%] was high in samples collected from female patients and percentage of the infections caused by the S. aureus in male and female patients was 47.9 and 52.1, respectively. During the study period, frequency of the E. coli was high during April to October and the prevalence of S. aureus was very common during March to October. Consistent but insignificant increase in the beta-lactamase producing S. aureus and E. coli was observed throughout the period of the study. However, increase in the beta-lactamase producing S. aureus and E. coli was above 80%. The prevalence of extended spectrum beta- lactamase [ESBL] in E. coli was increased from 13.85% in year 2000 to 22.66% in year 2003. The increasing in prevalence of microorganism, particularly of beta-lactamase producing E. coli and S. aureus and ESLB is alarming situation. Various measured like prescribing and patient compliance are required to control the increase in the prevalence of microorganism

Intramammary infections during the periparturient period in Argentine dairy heifers / Infecciones intramamarias durante el periparto en vaquillonas en Argentina

Prevalence of intramammary infections at prepartum and postpartum in primigravid heifers from five dairy herds located in the central dairy area of Argentina was determined. Mammary secretion samples from 140 heifers (560 mammary quarters) were obtained 14 days prior to the expected calving day and within 7 days after parturition and subjected to bacteriological analysis. No clinical mastitis cases were detected during the study. The number of infected heifers in at least one mammary quarter at pre and postpartum was 87 (62.2%) and 53 (37.8%), respectively. The most prevalent mastitis pathogens at prepartum among samples yielding a positive bacteriological culture were coagulasenegative staphylococci (69.07%), Staphylococcus aureus (12.71%) and Streptococcus uberis (4.42%). A decrease on isolation frequency of coagulase-negative staphylococci (53.41%) and S. uberis (2.27%) was observed at postpartum, while that of S. aureus showed an increase (21.59%). Presence of intramammary infections appeared to be associated with some management conditions. These results highlighted the need to improve diagnosis and control measures in replacement heifers.

Se determinó la prevalencia al preparto y posparto de infecciones intramamarias causadas por organismos patógenos de mastitis en vaquillonas primíparas de cinco establecimientos lecheros ubicados en la cuenca central santafesina. Se tomaron muestras de secreción mamaria de 140 vaquillonas (560 cuartos mamarios) aproximadamente 14 días antes de la fecha probable de parto y dentro de los 7 días posparto, y se procesaron bacteriológicamente. No se detectaron casos de mastitis clínicas durante el estudio. El número de vaquillonas infectadas en al menos un cuarto mamario al preparto y posparto fue de 87 (62,2%) y 53 (37,8%), respectivamente. Los organismos patógenos más prevalentes al preparto entre las muestras con cultivo bacteriológico positivo fueron estafilococos coagulasa negativos (69,07%), Staphylococcus aureus (12,7%) y Streptococcus uberis (4,42%). Al posparto se observó un descenso en la frecuencia de aislamiento de estafilococos coagulasa negativos (53,41%) y S. uberis (2,27%), mientras que la de S. aureus mostró un aumento (21,59%). La presencia de infecciones intramamarias pareció estar asociada con algunas prácticas de manejo. Estos resultados ponen de manifiesto la importancia de hacer extensivo el diagnóstico y control de la enfermedad a las vaquillonas de reemplazo antes de su ingreso al rodeo en ordeño.

Study of beta lactamase activity of Staphylococcus aureus isolated from healthy nasal carriers and hospital isolates.

Staphylococcus aureus (n=84) isolated from the nostrils of a healthy population from Kathmandu and from the infectious cases (n=100) from Tribhuvan University Teaching Hospital, Kathmandu, Nepal were tested from May 1996 to March 1997 in Central Department of Microbiology, Tribhuvan University, Kathmandu, Nepal by microbiological and chemical methods to find out their beta lactamase activity. Among the healthy population, in domiciliary conditions 21.4% of the isolates were found beta lactamase producers. The occurrence of beta lactamase producing S. aureus was greater among female (27.0%) than among male (17.0%), however it was not significant (X2 = 1.2309, P > 0.05). The occurrence of the same was observed high among 40 and above age groups (66.7%) and 0-9 age group (60.0%), however no association with any particular age group was observed (X2 = 16.8674, P > 0.05). The b lactamase activity of S. aureus hospital inpatients isolates was 75.0% showing high occurrence of b lactamase activity in hospital isolates compared to S. aureus isolates from healthy carriers (X2 = 52.4113, P < 0.001). No association of beta lactamase positive hospital isolates with gender (X2 = 0.2158, P > 0.05) and age group (X2 = 1.5522, P > 0.05) was observed. This study shows that the prevalence of beta lactamase positive S. aureus was greater in hospital cases than in nasal carriers in domiciliary condition indicating the requisition of further study in this field.

Amigdalitis aguda recurrente bacteriana: estudio prospectivo, comparativo y controlado de sus características clínicas y microbiológicas / Acute recurrent bacterial tonsillitis: prospective, comparative and controlled study of its clinical and microbiological characterisitics

Introducción: La amigdalitis aguda recurrente es una patología de frecuente consulta, es una de las indicaciones de amigdalectomía. No se sabe con exactitud el origen de esta patología. Objetivo: Identificar la microbiología y patrones de susceptibilidad de las bacterias en la amigdalitis aguda recurrente bacteriana (AARB) a los antimicrobianos más comúnmente en el medio nacional, usados en su tratamiento. Material y método: Se planificó un estudio prospectivo, controlado y ciego. Se evaluaron pacientes (casos) con antecedentes de AARB con indicación quirúrgica. Los criterios de inclusión de los casos fueron niños de ambos sexos entre 4 y 10 años, sin historia de inmunodeficiencias, no haber recibido antibióticos en los 15 días previos a la cirugía. Se definió como controles a los pacientes con antecedentes de apnea del sueño con indicación quirúrgica y sin antecedentes de AARB o cuadros sugerentes de amigdalitis en los últimos 6 meses. En todos los pacientes se utilizó la misma técnica de toma de muestra de tejido para cultivo y antibiograma. Para el estudio de sensibilidades se realizó un antibiograma de las cepas aisladas y se evaluó la presencia de beta lactamasas. Los datos fueron analizados con el programa S-plus para análisis univariado. Para evaluar proporciones se utilizó el test de chi-cuadrado o el test exacto de Fisher Las variables continuas fueron evaluadas con el test de Wilcoxon Two sample. Resultados: No se encontraron diferencias estadísticamente significativas entre las cepas encontradas en el grupo de casos y de controles. La bacteria aislada con más frecuencia fue Haemophilus influenzae en 26 muestras en cada grupo (81 por ciento), seguido por S. Aureusy Streptococccus beta hemolítico grupo A (SBHGA). En cuanto a las asociaciones de patógenos más frecuentes, se encontró que las mayores asociaciones fueron H. influenzae + S. aureusyH. influenzae + SBHGA. Tampoco hubo diferencias esrtadísticamente significativas en frecuencia de estas...

Staphylococcus aureus ampicillin-resistant from the odontological clinic environment

Foi avaliada a prevalência de Staphylococcus spp. e S. aureus no ambiente clínico odontológico, a produção de ß-lactamase e a susceptibilidade antibacteriana aos principais antibióticos utilizados na prática clínica. Durante 12 meses de coleta de amostras foram isolados 9775 UFC no meio de cultura AMS, demonstrando uma elevada quantidade de Staphylococcus spp. no ambiente clínico, provavelmente em decorrência da propagação de aerossóis. Um total de 3149 colônias (32,2%) foi sugestivo de estafilococos patogênicos. Coloração de Gram, teste de catalase, crescimento de colônias-malva sobre meio cromogênico e teste de coagulase confirmaram a identidade de 44 (0,45%) isolados de S. aureus. Destes, 35 isolados (79,5%) mostraram produção de ß-lactamase através de discos de CefinaseTM e resistência a ampicilina, eritromicina (7 isolados) e tetraciclina (1 isolado), sugerindo a existência de isolados multirresistentes. A avaliação do MIC de oxacilina através dos ensaios de Etest® mostrou padrões de susceptibilidade o que sugere a inexistência do gene mecA gene no DNA cromossômico. Estes resultados apontam para a necessidade de um maior conhecimento sobre os meios de contaminação e propagação deste microrganismo dentro da clínica odontológica.

Deteccion de la Desoxirribonucleasa Termoestable (Terminucleasa) directamente en el alimento / Detection of deoxyribonuclease thermostable (thermonuclease) directly in food thermostble

Se inocularon in vitro diversos alimentos de origen animal, con la cepa de Staphylococcus aureus FRI-S6, productora de la enterotoxina estafilococica del serotipo B y de la nucleasa tersmoestable. Se comprobo la concentracion microbiana de los inoculos, mediante siembra en superficie en medio Baird Parker. Se hallo termonucleasa en alimentos que contenian concentraciones microbianas de 10(6) - 10(7) UFC/g

Inactivación de ß-lactamasas por sulbactam en presencia de anticoagulante y en anaerobiosis / ß-lactamase inactivation by sulbactam in aerobiosis and anticoagulant

Se aislaron cepas de Staphylococcus aureus resistentes a penicilina y productoras de ß-lactamasas. Mediante el método de dilución en tubos, se calculó la concentración inhibitoria CIM para amoxicilina-sulbactam, con diferente tensión de oxígeno y frente a heparina. Los valores de CIM se redujeron significativamente al sumar sulbactam al antibiótico. La disminución del oxígeno no afectó la capacidad inhibidora de ß-lactamasas del sulbactam, del mismo modo que la presencia de heparina no interfirió en su efecto protector sobre la amoxicilina. Estos resultados reafirmaron el concepto de efectividad de la combinación amoxicilina-sulbactam sobre los procesos infecciosos a S. aureus productores de ß-lactamasas, aun en afecciones donde se genera anaerobiosis relativa y también en enfermos con tratamiento simultáneo con heparina

Actividad inmunoadyuvante del Staphylococcus aureus: efecto sobre la respuesta humoral y el sistema fagocítico mononuclear en ratas / Inmunoadyuvant activity of staphylococcus aureus:effect on humoral response and mononuclear phagocytic system in rats

Se estudió el efecto del S. aureus y de varios tipos celulares sobre: a) producción de anticuerpos (hemaglutininas) y b) estimulación del Sistema Fagocítico Mononuclear (S.F.M.). Ratas adultas, endocriadas,recibieron:I) células de exudado peritoneal (CEP); II) células del bazo (CB); III) células de bazo no-adherentes (CBN-A); IV) células de exudado peritoneal normal (CEPN); V) células de bazo normal (CBN); VI) células de bazo normal no-adherentes (CBN N-A); VII) S. aureas s.c. y VIII) (-). I, II y III proveían de ratas inoculadas 7 días antes con S. aureus y IV,V y VI de animales normales. Se sensibilizó con glóbulos rojos de carnero al 50 por ciento. Se determinó el título de hemaglutininas séricas totales y con 2 mercapto etanol en la Respuesta primaria y en la Respuesta secundaria, posterior al segundo inóculo. Se estimó peso y se practicó un estudio anatomopatológico del hígado y bazo de los animales tratados con S. aureus y testigos. Se hallaron diferencias significativas en el título de hemaglutininas en todos los días estudiados (Respuesta primaria y secundaria)-p<0,0l;p<0,05-entre los grupos I,II,III,VII vs. IV,V,VI y VIII. Se pesó el hígado y bazo (corregido/peso del animal) en ratas inoculadas con S. aureus (1) y sin tratamiento o control (2). Los valores fueron significativamente mayores en (1) (p<0,001). Hígado: a) 5,746 Ð 0,67; b) 3,609 Ð 0,456. Bazo: a)0,5698 Ð 0,067; b) 0,325 Ð 0,05. Las modificaciones anatomopatológicas en hígado y bazo se observaron con mayor frecuencia e intensidad en los animales tratados que en los testigos (p<0,01). Se confirma el efecto adyuvante del S. aureus, ya que produce aumento de peso e importantes modificaciones anatomopatológicas del órganos del S.F.M., eleva la respuesta humoral a un antígeno no relacionado y estimula la memoria inmunológica

Método para cuantificar actividad proteolítica sobre sustratos insolubles coloreados / Method for quantitative proteolytic activity about stained substrates insoluble

Se cuantificó la actividad proteolítica de Staphylococcus aureus aislados de infecciones del hombre, aplicando una modificación de la técnica efectuada por otros autores con Pseudomonas aeruginosa. Además del polvo de piel coloreado con Azul Brillante de Remazol utilizado con esta bacteria, se prepararon otros sustratos insolubles, tales como elastina-Rojo Congo, colágeno-Rojo Congo y polvo de ubre-Rojo Congo. Fue posible comprobar mayor actividad proteolítica sobre colágeno que sobre elastina, mientras que con los extractos o polvos tisulares se evidenció más proteólisis con polvo de ubre de vaca (PUH) que con polvo de piel (PPA). Cabe destacar que las cepas procedían de infecciones humanas, incluyendo afecciones no epidérmicas y una de colección ATCC. El método desarrollado constituyó una ventaja con respecto a las técnicas clásicas de bacteriología que detectan cualitativamente la actividad proteolítica