Identificación y sensibilidad a los antimicrobianos de aislados de estreptococos del grupo viridans provenientes de pacientes internados en un hospital universitario de la ciudad de Buenos Aires / Identification and antibiotic susceptibility of viridans group streptococci isolates recovered from patients hospitalized at a teaching hospital in Buenos Aires City

Los estreptococos del grupo viridans (EGV) son agentes causales de infecciones localizadas e invasivas. Dada la gravedad de las infecciones producidas por EGV sumada a las escasas comunicaciones actuales en nuestro país, los objetivos de este trabajo fueron la identificación y el estudio de la sensibilidad a los antibióticos de aislados caracterizados como EGV, recuperados de pacientes internados, para actualizar el conocimiento sobre el perfil de resistencia y la epidemiología de las infecciones ocasionadas por EGV. Se recuperaron 132 aislados de EGV en el Hospital de Clínicas «José de San Martín¼ en el período 2011-2015. La identificación se realizó mediante pruebas convencionales y espectrometría de masas (Matrix Assisted Laser Desorption Ionization - Time of Flight Mass Spectrometry). El grupo Streptococcus anginosus fue el más frecuente (42%) seguido por el grupo Streptococcus mitis (33%). Dentro del grupo S. mitis se excluyó a Streptococcus pneumoniae. El 100% de los aislados fue sensible a ertapenem, linezolid y vancomicina; el 96,9% a cef-triaxona y cefepima. Se encontró un 25,8% de resistencia a penicilina (I+R) fundamentalmente en aislados de grupo S. mitis. La resistencia a tetraciclina fue del 27,2% y solo 2/132 aislados fueron resistentes a levofloxacina. Los valores de CIM de gentamicina oscilaron entre 0,5 y 32 -og/ml. El 17,4% de los aislados presentó resistencia a eritromicina sin diferencia significativa en la distribución de fenotipos M y MLS. Los resultados muestran la importancia de la vigilancia continua de las infecciones producidas por estos microorganismos con el fin de generar aportes para la elección de la terapia antibiótica adecuada.

Members of the viridans group streptococci (VGS) are the cause of local and invasive infections. Due to the severity of these infections and taking into account that reports regarding epidemiological aspects are scarce, the aims of this work were the identification and the study of the antibiotic susceptibility profiles of the isolates recovered from patients that were hospitalized in order to find out about the resistance level and the epidemiology of infections in which VGS are involved. A hundred and thirty two isolates identified as VGS were isolated at Hospital de Clínicas «José de San Martín¼ during the period 2011-2015. The identification was performed by biochemical test and mass spectrometry by Matrix Assisted Laser Desorption Ionization -Time of Flight Mass Spectrometry. Streptococcus anginosus group was prevalent (42%) followed by Streptococcus mitis group (33%). In the latter, isolates of Streptococcus pneumoniae were excluded. All the VGS isolates were susceptible to ertapenem, meropenem, linezolid and vancomycin; 25.8% were resistant (I+R) to penicillin, being prevalent in the S. mitis group. Regarding ceftriaxone and cefepime 96.9% of the isolates were susceptible. Only two isolates were resistant to levofloxacin, 27.2% to tetracycline and it was not found high level resistance to gentamycin (MIC range 0.5-32 µg/ml). Resistance to erythromycin was 17.4% with no significant difference between M and MLS phenotypes. The most active antibiotics were in addition to ceftriaxone and cefepime, vancomycin, ertapenem, meropenem and linezolid. These results highlight the importance of the continuous surveillance of the infections caused by VGS in order to predict a correct antibiotic therapy.

Microbiology and clinical characteristics of viridans group streptococci in patients with cancer

ABSTRACT This study assessed the microbiology, clinical syndromes, and outcomes of oncologic patients with viridans group streptococci isolated from blood cultures between January 1st, 2013 and December 31st, 2016 in a referral hospital in Mexico using the Bruker MALDI Biotyper. Antimicrobial sensitivity was determined using BD Phoenix 100 according to CLSI M100 standards. Clinical information was obtained from medical records and descriptive analysis was performed.Forty-three patients were included, 22 females and 21 males, aged 42 ± 17 years. Twenty (46.5%) patients had hematological cancer and 23 (53.5%) a solid malignancy. The viridans group streptococci isolated were Streptococcus mitis, 20 (46.5%); Streptococcus anginosus, 14 (32.6%); Streptococcus sanguinis, 7 (16.3%); and Streptococcus salivarius, 2 (4.7%). The main risk factors were pyrimidine antagonist chemotherapy in 22 (51.2%) and neutropenia in 19 (44.2%) cases, respectively. Central line associated bloodstream infection was diagnosed in 18 (41.9%) cases. Septic shock occurred in 20.9% of patients, with an overall mortality of 18.6%. Only four S. mitis revealed penicillin-resistance.Our results are similar to those of other series, identifying these bacteria as emerging pathogens with significant morbidity and mortality in oncologic patients. The MALDI-TOF system increased the rate of viridans group streptococci isolation in this population.

Species-Specific Difference in Antimicrobial Susceptibility Among Viridans Group Streptococci

BACKGROUND: Viridans group streptococci (VGS) are both commensal microbes and potential pathogens. Increasing resistance to penicillin in VGS is an ongoing issue in the clinical environment. We investigated the difference in susceptibility and resistance to penicillin among various VGS species. METHODS: In total 1,448 VGS isolated from various clinical specimens were analyzed over a two-yr period. Identification and antimicrobial susceptibility test was performed by the automated VITEK 2 system (bioMerieux, France) or the MicroScan MICroSTREP system (Siemens, Germany). RESULTS: Among the 1,448 isolates, 412 were isolated from blood (28.4%). Streptococcus mitis group was the most frequently isolated (589 isolates, 40.7%), followed by the S. anginosus group (290 isolates, 20.0%), S. sanguinis group (179 isolates, 12.4%) and S. salivarius group (57 isolates, 3.9%). In total, 314 isolates could not be identified up to the species level. The overall non-susceptibility to penicillin was observed to be 40.0% (resistant, 11.2% and intermediately resistant, 28.8%) with uneven distribution among groups; 40.2% in S. sanguinis group (resistant, 5.0% and intermediately resistant, 35.2%), 60.3% in S. mitis group (resistant, 20.9% and intermediately resistant, 39.4%), 78.9% in S. salivarius group (resistant, 8.8% and intermediately resistant, 70.1%), and 6.2% in S. anginosus group (resistant, 1.7% and intermediately resistant, 4.5%). CONCLUSIONS: Antimicrobial resistance patterns towards penicillin show differences among various VGS; this should be considered while devising an effective antimicrobial treatment against VGS.

Antimicrobial and plaque inhibitory potential of herbal and probiotic oral rinses in children: A randomized clinical trial.

Background: Antimicrobial agents serve as an effective adjunct with mechanical means in plaque control. Chlorhexidine has been the gold standard in the field of dentistry, but these days a growing number of dentists are embracing the philosophy that natural agents are better for children’s oral health, and the focus is shifted toward biogenic agents for oral hygiene maintenance in children. Aim: The aim was to evaluate antimicrobial and plaque inhibitory potential of herbal and probiotic rinses against Streptococcus viridans with commonly used antimicrobial agent like 0.2% chlorhexidine digluconate. Materials and Methods: A randomized clinical trial was conducted on 60 subjects aged between 6 and 14 years and were divided into three groups comprising 20 subjects in each group. Three oral rinses were administered twice daily for a period of 1 week. Estimation of plaque scores and S. viridans counts was done before and after intervention, and the results were statistically analyzed. Results: The change in mean plaque index in Groups A, B, and C was 0.28 ± 0.16, 1.37 ± 0.43, and 0.60 ± 0.35 respectively. Furthermore, change in mean log10 colony forming unit (CFU)/ml of S. viridans in Groups A, B, and C was 0.13 ± 0.06, 0.53 ± 0.17, and 0.22 ± 0.06 CFU/ml, respectively. Conclusion: Based on observations done during the course of study herbal rinse proved equally effective as 0.2% chlorhexidine digluconate in reducing S. viridans counts and plaque accumulation after 1 week of intervention, whereas probiotic rinse was least effective. However, long‑term clinical trial with larger sample size needs to be undertaken, especially to evaluate beneficial effects of biogenic agents such as herbal and probiotic rinses.

Efeito da penicilina G a cada três semanas sobre o surgimento de Streptococcus viridans resistentes à penicilina na microflora oral / Effect of penicillin G every three weeks on oral microflora by penicillin resistant Viridans Streptococci

FUNDAMENTO: Penicilina G benzatina a cada 3 semanas é o protocolo padrão para a profilaxia secundária para febre reumática recorrente. OBJETIVO: Avaliar o efeito da penicilina G benzatina em Streptococcus sanguinis e Streptococcus oralis em pacientes com doença valvular cardíaca, devido à febre reumática com recebimento de profilaxia secundária. MÉTODOS: Estreptococos orais foram avaliados antes (momento basal) e após 7 dias (7º dia) iniciando-se com penicilina G benzatina em 100 pacientes que receberam profilaxia secundária da febre reumática. Amostras de saliva foram avaliadas para verificar a contagem de colônias e presença de S. sanguinis e S. oralis. Amostras de saliva estimulada pela mastigação foram serialmente diluídas e semeadas em placas sobre agar-sangue de ovelhas seletivo e não seletivo a 5% contendo penicilina G. A identificação da espécie foi realizada com testes bioquímicos convencionais. Concentrações inibitórias mínimas foram determinadas com o Etest. RESULTADOS: Não foram encontradas diferenças estatísticas da presença de S. sanguinis comparando-se o momento basal e o 7º dia (p = 0,62). No entanto, o número existente de culturas positivas de S. oralis no 7º dia após a Penicilina G benzatina apresentou um aumento significativo em relação ao valor basal (p = 0,04). Não houve diferença estatística existente entre o momento basal e o 7º dia sobre o número de S. sanguinis ou S. oralis UFC/mL e concentrações inibitórias medianas. CONCLUSÃO: O presente estudo mostrou que a Penicilina G benzatina a cada 3 semanas não alterou a colonização por S. sanguinis, mas aumentou a colonização de S. oralis no 7º dia de administração. Portanto, a susceptibilidade do Streptococcus sanguinis e Streptococcus oralis à penicilina G não foi modificada durante a rotina de profilaxia secundária da febre reumática utilizando a penicilina G. (Arq Bras Cardiol. 2012; [online].ahead print, PP.0-0).

BACKGROUND: Benzathine penicillin G every 3 weeks is the standard protocol for secondary prophylaxis for recurrent rheumatic fever. OBJECTIVE: Assess the effect of Benzathine penicillin G on Streptococcus sanguinis and Streptococcus oralis in patients with cardiac valvular disease due to rheumatic fever receiving secondary prophylaxis. METHODS: Oral streptococci were evaluated before (baseline) and after 7 days (day 7) with Benzathine penicillin G in 100 patients receiving routine secondary rheumatic fever prophylaxis. Saliva samples were evaluated for colony count and presence of S. sanguinis and S. oralis. Chewing-stimulated saliva samples were serially diluted and plated onto both nonselective and selective 5% sheep blood agar containing penicillin G. The species were identified using conventional biochemical tests. Minimal inhibitory concentrations were determined with the Etest. RESULTS: No statistical differences were found in the presence of S. sanguinis comparing baseline and day 7 (p = 0.62). However, the existing number of positive cultures of S. oralis on day 7 after Benzathine penicillin G presented a significant increase compared to baseline (p = 0.04). No statistical difference was found between baseline and day 7 concerning the number of S. sanguinis or S. oralis CFU/mL and median minimal inhibitory concentrations. CONCLUSION: This study showed that Benzathine penicillin G every 3 weeks did not change the colonization by S. sanguinis, but increased colonization of S. oralis on day 7 of administration. Therefore, susceptibility of Streptococcus sanguinis and Streptococcus oralis to penicillin G was not modified during the penicillin G routine secondary rheumatic fever prophylaxis. (Arq Bras Cardiol. 2012; [online].ahead print, PP.0-0).

Efficacy of various spray disinfectants on irreversible hydrocolloid impression materials: An in vitro study.

Background: Most of the materials (casts, impressions, etc.) that are sent to the dental laboratories show the presence of numerous pathogenic microorganisms. All the spray disinfectants are not equally effective against these microorganisms. Aims and Objectives: The aim was to compare the effectiveness of different spray disinfectants on irreversible hydrocolloid impressions and to find out the most effective dilution, contact time, and effect against each microorganism studied. Materials and Methods: The effects of four spray disinfectants, 5.25% sodium hypochlorite, 0.525% sodium hypochlorite, 1:213 (1 part in 213 parts of water) povidone iodine, and 2% glutaraldehyde along with control (distilled water) on irreversible hydrocolloid impressions contaminated with Staphylococcus aureus, Bacillus subtilis and Streptococcus viridans were studied. Results: Sodium hypochlorite, 5.25%, showed 1-min exposure time which was able to effect a 4log10 reduction in bacterial counts against S. aureus and S. viridans followed by 0.525% sodium hypochlorite and 2% glutaraldehyde for 10 min. None were able to effect a 4 log10 reduction against B. subtilis. Conclusion: Sodium hypochlorite with a concentration of 5.25% was the most effective disinfectant and required the shortest contact time (1 min). Not all ADA-approved concentrations of surface disinfectants work equally well on irreversible hydrocolloid impression materials.

Evaluation of the MicroScan MICroSTREP Plus Antimicrobial Panel for Testing beta-Hemolytic Streptococci and Viridans Group Streptococci / 대한진단검사의학회지

BACKGROUND: In order to determine the clinical usefulness of the MicroScan (Siemens Healthcare Diagnostics, USA) MICroSTREP plus antimicrobial panel (MICroSTREP) for testing antimicrobial susceptibility of beta-hemolytic streptococci (BHS) and viridans group streptococci (VGS), we compared the accuracy of MICroSTREP with that of the CLSI reference method. METHODS: Seventy-five BHS and 59 VGS isolates were tested for antimicrobial susceptibility to ampicillin, penicillin, cefotaxime, meropenem, erythromycin, clindamycin, levofloxacin, and vancomycin by using MICroSTREP and the CLSI agar dilution method. RESULTS: The overall essential agreement with regard to minimum inhibitory concentrations (MICs) (within +/-1 double dilution) between MICroSTREP and the CLSI reference method was 98.2%, and categorical agreement (CA) was 96.9%. For the BHS isolates, the CA for erythromycin was 96.0%, whereas that for cefotaxime, meropenem, levofloxacin, and vancomycin (for ampicillin, penicillin, and clindamycin; 98.7%) was 100%. For the VGS isolates, the CA for penicillin was 84.7% and that for erythromycin, clindamycin, and vancomycin (for meropenem, 86.5%; for ampicillin, 88.1%; and for cefotaxime and levofloxacin, 96.6%) was 100%. All categorical errors of penicillin and ampicillin in the VGS isolates were minor. CONCLUSIONS: The accuracy of MICroSTREP is comparable to that of the CLSI reference method, suggesting that this panel can be effective for testing antimicrobial susceptibility of BHS and VGS.

Influencia de la concentración inhibitoria mínima de penicilina en la acción sinérgica de su combinación con gentamicina frente a estreptococos del grupo viridans / Influence of penicillin minimal inhibitory concentration in the synergy between penicillin and gentamicin in viridans group streptococci

Los porcentajes de resistencia a penicilina entre los estreptococos del grupo viridans han llegado a niveles superiores al 60% en algunos estudios realizados en la década pasada, y en recientes trabajos se los encontró asociados a un mayor índice de mortalidad en las bacteriemias. Aún no se conoce cuál es el nivel de concentración inhibitoria mínima de penicilina para el cual resulta imposible lograr un efecto sinérgico con algún aminoglucósido. Con este propósito, se estudió la sensibilidad a penicilina de 28 cepas de estreptococos del grupo viridans aisladas de materiales clínicamente significativos en el Hospital de Pediatría "Prof. Dr. Juan P. Garrahan". Se seleccionaron siete aislamientos pertenecientes al grupo mitis con distintas características de sensibilidad, y con ellos se ensayó la curva de muerte frente a penicilina, gentamicina y penicilina más gentamicina, con concentraciones de penicilina por encima y por debajo de su concentración inhibitoria mínima. En ningún caso se observó sinergia cuando la concentración de penicilina fue inferior a la concentración inhibitoria mínima, al menos en este grupo particular de estreptococos que presentaron concentraciones inhibitorias mínimas de gentamicina ³ 16 µg/ml. Se encontró sinergia en cinco de las siete cepas cuando se trabajó con concentraciones de penicilina superiores a la concentración inhibitoria mínima. En las otras dos, se detectaron enzimas modificadoras de aminoglucósidos.

Penicillin resistance rates higher than 60% have been recorded in viridans group streptococci by some authors during the 90's and recently such resistance was associated with higher levels of mortality in bacteremia. The lowest minimal inhibitory concentration of penicillin for which synergy with aminoglycosides is not yet possible is still unknown. In order to try to dilucidate this puzzle, a study on the susceptibility to penicillin of 28 strains of viridans group streptococci isolated from significant samples in the Hospital de Pediatría "Prof. Dr. Juan P. Garrahan" was carried out. Seven mitis group isolates presenting different susceptibility patterns were selected for performing time-killing curves with penicillin, gentamicin, and penicillin plus gentamicin, using higher and lower penicillin concentrations than their minimal inhibitory concentrations. Synergy was not observed when the penicillin concentration was lower than the minimal inhibitory concentration, at least in these strains with minimal inhibitory concentrations of gentamicin ³ 16 µg/ml. When using penicillin in higher concentrations than the minimal inhibitory concentration, synergy was found in five of the seven strains. Aminoglycoside-modifying enzymes were found in the two other streptococci.

Effect of changes in diagnosis and management of active infective endocarditis on the clinical outcome at Srinagarind Hospital.

BACKGROUND: In recent years, diagnostic methods and treatment of infective endocarditis (IE) have been improved. It is not known whether the clinical outcome is any better. OBJECTIVE: To assess the effect of changes on the clinical outcomes of IE patients. MATERIAL AND METHOD: The authors performed a retrospective study comparing IE patients hospitalized at Srinagarind hospital during the period from 1/1/1990 to 31/12/2002. The authors classified the patients according to the period of diagnosed from 1990 to 1993 (n=57), 1994 to1997 (n=71), and 1998 to 2002 (n=72) cohorts. RESULTS: There were two hundred IE patients in the present study. Mean age and degenerative heart disease were increasing. Operative and in-hospital mortality were decreasing. Overall survival rate was 81% at the first year 60% at 5 years, 55% at 12 years in surgically treated patients, with 30-day mortality in 27.1% mostly from the 1990 to 1993 cohort. In medically treated IE, overall the survival rate was 37% in the first year, 32% at 5 years, 20% at 12 years, with 30-day mortality in 72.86% mostly in the 1990 to 1993 cohort. Early surgical intervention, improved long-term survival rates (hazard ratio 0.23; 95% CI 0.14-0.37), severe congestive heart failure (hazard ratio 1.87; 95% CI 1.17-2.99) and renal failure (hazard ratio 4.10; 95% CI 2.05-7.84) are the predictors of mortality by multivariate analysis. Survival rate from 1998 to 2002 cohort was 85%, 1994 to 1997 cohort was 54% and 1993 to 1990 cohort was 27% at 1-year (p < 0.001). CONCLUSION: The data indicated that the changing clinical outcome of this disease, reflected improvements in diagnostic method and treatment. Although IE remains a serious condition characterized by significant morbidity and mortality, the overall survival rate has significantly improved over time. The authors therefore, believe that early diagnosis and prompt treatment both medical or surgical interventions will improve the outcome of IE patients.

Atividade antimicrobiana in vitro de compostos a base de hidróxido de cálcio e tergentol em diferentes concentrações sobre bactérias orais / Antimicrobial activity of calcium hydroxide and tergentol on different concentrations in oral bactéria

OBJETIVOS: Este estudo realizado no departamento de Odontologia da Universidade Federal do Rio Grande do Norte foi idealizado com propósito de pesquisar a ação "in vitro" de soluções a base de Ca(OH)2 e tergentol frente a bactérias colonizadoras da cavidade bucal e cariogênicas visando contribuir para o estudo sobre os agentes químicos para controle do biofilme dental. MÉTODOS: Testou-se através de discos de antibiograma e ação em bactérias formadoras de biofilme a ação antimicrobiana de algumas soluções de Ca(OH)2 e tergentol usando-se como padrão-ouro o digluconato de clorexidina a 0,12 por cento. RESULTADOS: Os resultados foram analisados através do teste de Kruskal-Wallis e do pós-teste de comparação múltipla de Dunn com valores de p sempre menores que 0,05. A clorexidina obteve melhores resultados em nível de ação antimicrobiana em relação às soluções a base de Ca(OH)2 e tergentol. A diferença estatísta da ação da clorexidina frente às demais soluções e aos tipos bacterianos testados não foi significativa para a maiorias dos cruzamentos. CONCLUSÕES: O digluconato de clorexidina a 0,12 por cento foi o egente antimicrobiano mais efetivo neste estudo. As soluções a base de hidróxido de cálcio não apresentaram efetividade satisfatória em relação a clorexidina, principalmente em relação ao Streptococcus mutans. São necessários estudos mais aprofundados para se determinar o real potencial do HCT 20 como anti-séptico bucal.

Mechanism of macrolide resistance in Malaysian isolates of group A streptococci

Hundred and forty four strains of group A Streptococci isolated from various clinical sources were tested for their susceptibility to antimicrobial agents by the disc diffusion technique in accordance with the National Committee for Clinical Laboratory Standards [NCCLS]. Erythromycin-resistant isolates were reconfirmed by E-test following the manufacturer's instructions. The phenotypes of the erythromycin-resistant strains were then determined by the triple disc test. Mulitplex polymerase chain reaction [PCR] was performed for the identification of resistance genes. The overall frequency for GAS erythromycin resistance was 4.86%, mostly from throat sources [p < 0.05]. All the erythromycin-resistant strains were susceptible to vancomycin, cefotaxime and cefuroxime. Tetracycline resistance was 59.72% while resistance to chloramphenicol was 0.69%. All 144 isolates were susceptible to penicillin, clindamycin and spiramycin. Minimum inhibition concentrations [MICs] of the 7 erythromycin-resistant strains ranged from 2 g/ml to 12 g/ml. All the erythromycin-resistant strains were found to be of the M phenotype possessing the mefA gene which is responsible for mediating the macrolide efflux mechanism