Prevalencia de Staphylococcus aureusy su sensibilidad antibiótica en aislamientos en infecciones de piel y partes blandas en pacientes ambulatorios / Staphylococcus aureus prevalence and antimicrobial susceptibility in isolates from skin and soft tissue infections in outpatients

ntroducción: Las infecciones de piel y partes blandas (IPPB) constituyen la tercera causa de consulta en nuestro centro. S.aureus es el agente etiológico más frecuente en este tipo de infecciones y la meticilino resistencia es clínicamente el mecanismo de resistencia más importante. El objetivo de este trabajo fue analizar la prevalencia de los distintos agentes etiológicos en IPPB en pacientes ambulatorios, así como también estudiar su sensibilidad a los antibióticos y resistencias acompañantes más frecuentes. Materiales y métodos: Estudio descriptivo y retrospectivo que incluyó todas las muestras provenientes de IPPB de pacientes ambulatorios desde octubre de 2017 a abril de 2022. Resultados: Se obtuvieron 180 cultivos positivos de muestras provenientes de IPPB durante el periodo estudiado, 12 fueron infecciones polimicrobianas. En total se obtuvieron 307 aislamientos: el microorganismo aislado con mayor frecuencia fue S.aureus (111; 36,2%). Se hallaron 71 SAMR (64%) y 40 SAMS (36%). De los SAMR, 67 (95%) fueron comunitarios (SAMRC) por criterios microbiológicos, y 4 SAMR hospitalarios (5%). De las cepas SAMRC, 44 (66%) no presentaron resistencias acompañantes, 15 (22% ) fueron resistentes a eritromicina, 12 (18%) a gentamicina y 7 (10%) a clindamicina. Conclusiones: El microorganismo más frecuentemente aislado en IPPB en pacientes ambulatorios fue el S.aureus y 67 aislamientos fueron categorizados como SAMRC por lo cual es necesario considerar al SAMRC como un patógeno frecuente. Debido a la baja resistencia hallada para CLI y TMS ambos podrían ser de elección en el tratamiento empírico en las IPPB en pacientes ambulatorios

Background:S. aureus is the main cause of skin and soft tissues infections (SSTIs) in immunocompetent patients. This type of infection is the third cause of medical consultation in our center. Our objective was to evaluate the prevalence of S. aureus, as well as its sensitivity to antimicrobials, isolated from skin and soft tissue samples from outpatients at an interzonal general acute care hospital located in Buenos Aires, Argentina.Methods: Descriptive and retrospective study that included all outpatient SSTIs samples from October 2017 to April 2022.Results: We obtained 215 positive cultures of samples from SSTIs during the study period. Of a total of 276 isolates: the most frequently isolated microorganism wasS. aureus (111; 40.22%). The prevalence of S. aureuswas 51.63%. We found 71 MRSA (63.96%). Of the SAMR strains, 60.56% did not present accompanying resistance, and only 8 isolates (11.27%) showed resistance to clindamycin. All SAMRs remained sensitive to minocycline and trimethoprim-sulfamethoxazole.Conclusions: The most frequently isolated microorganism in SSTIs was S. aureus and 71 isolates were categorized as SAMR, therefore it is necessary to consider SAMR as a frequent pathogen. Due to the low resistance found for CLI and TMS, they should be considered for empirical treatment in SSTIs in outpatients

Individual variation is the key to the development of a vaccine against Staphylococcus aureus: a comparative study between mice lineages

Bacterial infections occur worldwide and are a major public health problem. Among pathogens, Staphylococcus aureus is the main causative agent of bacterial diseases in the world. This study aimed to evaluate which components of the immune system could act protectively against a S. aureus infection in intradermally immunized mice. C57BL/6 and A/j mice were immunized intradermally with S. aureus inactivated by heat and then challenged with viable strains in an air pouch model. At 6, 12, and 24 h after the challenge, euthanasia was performed, and the cellular profile of the inflammatory infiltrate, cytokines, and the bacterial load were evaluated in the air pouch lavages. Immunized mice demonstrated that the intradermal immunization with S. aureus promoted protection in C57BL/6 mice by reducing the bacterial, which was correlated with increased serum concentration of IgG antibodies (IgG1 and IgG2a) against S. aureus. The increase in IgG2a antibody levels was correlated with a decrease of bacterial load in intradermally immunized C57BL/6 mice, along with production of IL-17A at the inflammation site, as well as IgG1consumption. Similar results were not found in the A/j lineage. In conclusion, a vaccine against S. aureus should focus more on the individual characteristics of the host because it is a determinant factor for the success of the immunization.

Predictors of Conversion from Radial Into Femoral Access in Cardiac Catheterization / Fatores Preditivos da Conversão de Acesso Radial em Femoral no Cateterismo Cardíaco

Background: Fewer bleeding complications and early ambulation make radial access a privileged route for cardiac catheterization. However, transradial (TR) approach is not always successful, requiring its conversion into femoral access. Objectives: To evaluate the rate of conversion from radial into femoral access in cardiac catheterization and to identify its predictors. Methods: Prospective dual-center registry, including 7632 consecutive patients undergoing catheterization via the radial access between Jan/2009 and Oct/2012. We evaluated the incidence of conversion into femoral access and its predictors by logistic regression analysis. Results: The patients’ mean age was 66 ± 11 years, and 32% were women. A total of 2969 procedures (38.4%) were percutaneous coronary interventions (PCI), and the most used first intention arterial access was the right radial artery (97.6%). Radial access failure rate was 5.8%. Independent predictors of conversion from radial into femoral access were the use of short introducer sheaths (OR 3.047, CI: 2.380-3.902; p < 0.001), PCI (OR 1.729, CI: 1.375-2.173; p < 0.001), female sex (OR 1.569, CI: 1.234-1.996; p < 0.001), multivessel disease (OR 1.457, CI: 1.167-1.819; p = 0.001), body surface area (BSA) ≤ 1.938 (OR 1.448, CI: 1.120-1.871; p = 0.005) and age > 66 years (OR 1.354, CI: 1.088-1.684; p = 0.007). Conclusion: Transradial approach for cardiac catheterization has a high success rate and the need for its conversion into femoral access in this cohort was low. Female sex, older age, smaller BSA, the use of short introducer sheaths, multivessel disease and PCI were independent predictors of conversion into femoral access. .

Fundamento: Menos complicações hemorrágicas e deambulação precoce fazem do acesso radial uma via privilegiada para cateterismo cardíaco. Entretanto, a abordagem transradial (TR) nem sempre é bem-sucedida, sendo necessária a sua conversão em acesso femoral. Objetivo: Avaliar a taxa de conversão do acesso radial em femoral no cateterismo cardíaco e identificar seus fatores preditivos. Métodos: Registro prospectivo de dois centros, incluindo 7.632 pacientes consecutivos submetidos a cateterização via acesso radial entre janeiro de 2009 e outubro de 2012. Avaliou-se a incidência de conversão em acesso femoral e seus fatores preditivos através de análise de regressão logística. Resultados: A idade média dos pacientes foi de 66 ± 11 anos, sendo 32% deles mulheres. Houve 2.969 (38.4%) intervenções coronarianas percutâneas (ICP),sendo a artéria radial direita a primeira escolha mais usada (97,6%). A taxa de insucesso do acesso radial foi de 5,8%. Fatores preditivos independentes da conversão do acesso radial em femoral foram o uso de bainhas introdutoras curtas (OR 3,047; IC: 2,380-3,902; p < 0,001), ICP (OR 1,729; IC: 1,375-2,173; p < 0,001), sexo feminino (OR 1,569;IC: 1,234-1,996; p < 0,001), doença multiarterial (OR 1,457; IC: 1,167-1,819; p = 0,001), área de superfície corporal(ASC) ≤ 1,938 (OR 1,448; IC: 1,120-1,871; p = 0,005) e idade > 66 anos (OR 1,354; IC: 1,088-1,684; p = 0,007). Conclusão: A abordagem transradial para cateterismo cardíaco tem alta taxa de sucesso e a necessidade de sua conversão em acesso femoral nesta coorte foi baixa. Os fatores preditivos independentes de sua conversão em acesso femoral foram: sexo feminino; idade mais avançada; menor ASC; uso de bainhas introdutoras curtas; doença multiarterial; e ICP. .

Presence of Toll Like Receptor-2 in spleen, lymph node and thymus of Swiss albino mice and its modulation by Staphylococcus aureus and bacterial lipopolysaccharide.

Toll-like receptors (TLR) are a family of pattern recognition receptors identifying pathogen associated molecular patterns (PAMPs). They play a critical role in the innate immune response during the initial interaction between the infecting microorganism and phagocytic cells. Here, we verified the presence of TLR-2 in spleen, lymph node and thymus of Swiss albino mice and their modulation after infection with Staphylococcus aureus and Lipopolysaccharide (LPS) challenge. It was seen that TLR-2 gene transcribed to its respective mRNA on S. aureus infection, in thymus, spleen and lymph node of mice but their levels and mode of expression varied. When challenged with LPS no prominent changes in the expression of TLR-2 receptor was observed but its expression increased gradually with time in the thymus, spleen and lymph node of S. aureus infected mice. TLR-2 expression was also found enhanced in infected splenic macrophages. By studying the serum cytokine profile the functionality of the receptor was measured. The results indicate the presence of TLR-2 in thymus, spleen and lymph node of Swiss albino strain of mice and that they are modulated by S. aureus.

Distinct cytokine profiles of circulating mononuclear cells stimulated with Staphylococcus aureus enterotoxin A in vitro during early and late episodes of chronic osteomyelitis

We investigated the cytokine profile of peripheral mononuclear cells from chronic osteomyelitis (OST) patients following in vitro stimulation with staphylococcal enterotoxin A (SEA). We demonstrate that stimulation with SEA induced prominent lymphocyte proliferation and high levels of tumour necrosis factor (TNF)-α, interleukin (IL)-4 and IL-10 secretion in both OST and non-infected individuals (NI). Even though stimulation with SEA had no impact on IL-6 production in either patient group, the baseline level of IL-6 production by cells from OST patients was always significantly less than that produced by cells from NI. After classifying the osteomyelitic episodes based on the time after the last reactivation event as "early" (1-4 months) or "late" osteomyelitis (5-12 months), we found that increased levels of TNF-α and IL-4 in combination with decreased levels of IL-6 were observed in the early episodes. By contrast, increased levels of IL-10, IL-2 and IL-6 were hallmarks of late episodes. Our data demonstrate that early osteomyelitic episodes are accompanied by an increased frequency of "high producers" of TNF-α and IL-4, whereas late events are characterised by increased frequencies of "high producers" of IL-10, IL-6 and IL-2. These findings demonstrate the distinct cytokine profiles in chronic osteomyelitis, with a distinct regulation of IL-6 production during early and late episodes.

Piomiositis en un paciente inmunocompetente / Pyomyositis in an immunocompetent patient

We report a case of pyomyositis in a 59 year-old immunocompetent male patient caused by methicillin-susceptible Staphylococcus aureus. A CT scan of the chest demonstrated a lesion of the pectoral muscles. The patient was treated with surgical drainage and cephalexin. Pyomyositis is a rare and potentially serious infection that requires early recognition and prompt treatment.

Se presenta un caso de piomiositis en un varón de 59 años, inmunocompetente, producida por Staphylococcus aureus sensible a meticilina, afectando los músculos pectorales del hemitórax derecho. Fue tratado con drenaje quirúrgico y cefalexina. La piomiositis es una infección infrecuente y potencialmente seria que requiere de un reconocimiento temprano y tratamiento oportuno.

Expression of cell surface markers on methicillin resistant Staphylococcus aureus stimulated lymphocytes.

BACKGROUND & OBJECTIVE: Methicillin-resistant Staphylococcus aureus (MRSA) has gradually been increasing, new strategies in the treatment of MRSA infections are required. This depends on the understanding of the infection pathogenesis and the immune response. This study was therefore designed to determine the immune response which develops during MRSA infection and the role of chemokines in this response, and also to compare the results with the changes occurring after MSSA infection. METHODS: The expression of the surface markers of human lymphocytes stimulated by heat-killed MRSA or MSSA was analysed by flow cytometry. The chemokine levels in the lymphocytes culture supernatants stimulated or not stimulated by microorganisms were determined by ELISA. RESULTS: Human peripheral blood mononuclear cells (PBMCs) stimulated by MRSA the levels of CD4(+)CD25(+) regulatory T cells, CD69 expressions in the activated T lymphocytes, CD3(-)CD16(+)CD56(+) NK cells and the levels of MIP-1alpha, MIP-1beta, MCP-1 chemokines increased as compared to the cells not stimulated by MRSA. Although stimulation by MSSA caused an increase in CD25 expression after 24 h, the increase was found to be lower than the one caused by MRSA stimulation. The increase in CD69 expression was statistically significant compared to the cells stimulated by MRSA. Different from the cells stimulated by MRSA, no change was observed in the expressions of CD54 and CD3(-)CD16(+)CD56(+) NK cells in the cells stimulated by MSSA. INTERPRETATION & CONCLUSION: Our findings showed that cellular as well as humoral immunity are critical in MRSA infection and that T cell activation and the increase in chemokines may play a role in the regulation of immune response.

Distribution of the putative virulence factor encoding gene sheta in Staphylococcus hyicus strains of various origins

In the present study, Staphylococcus (S.) hyicus strains isolated in Russia (n = 23) and Germany (n = 17) were investigated for the prevalence of the previously described genes sheta and shetb. Sheta was detected in 16 S. hyicus strains. Sheta-positive strains were mainly found among strains isolated from exudative epidermitis, and frequently together with the exfoliative toxin-encoding genes exhD and exhC. Partial sequencing of sheta in a single S. hyicus strain revealed an almost complete match with the sheta sequence obtained from GenBank. None of the S. hyicus strains displayed a positive reaction with the shetb-specific oligonucleotide primer used in the present study. According to the present results, the exotoxin encoding gene sheta seems to be distributed among S. hyicus strains in Russia and Germany. The toxigenic potential of this exotoxin, which does not have the classical structure of a staphylococcal exfoliative toxin, remains to be elucidated.

Unique features of bovine lymphocytes exposed to a staphylococcal enterotoxin

We previously demonstrated that stimulation of bovine peripheral blood mononuclear cells (PBMCs) with staphylococcal enterotoxin C (SEC), led to an inversion of the CD4(+):CD8(+) T cell ratio and generation of an atypical CD8(+) T cell subpopulation expressing CD26. In the present study, we examined T cell apoptosis and proliferation profiles of PBMC subpopulations in cultures stimulated with SEC. Unlike when stimulated with concanavalin A, nucleic acid synthesis in bovine PBMC cultures stimulated with SEC was low during the first four days but increased greatly on day 5. In contrast, nucleic acid synthesis in human PBMC cultures stimulated with SEC increased continuously. To investigate the mechanism of delayed bovine T cell proliferation, various cell phenotypes were monitored. The inversion of the bovine CD4(+):CD8(+) T cell ratio in PBMC cultures stimulated by SEC was associated with higher proliferation and lower apoptosis of CD8(+) T cells compared to CD4(+) T cells. The mRNA levels for interleukin (IL)-4 and IL-13 were sustained over 4 days but IL-12 mRNA levels dropped to background on day 2. These data suggest that SEC induces a prolonged Th-2- biased microenvironment, and together with the inversion of the bovine CD4(+):CD8(+) T cell ratios in bovine PBMC cultures with SEC, may in part explain the inability of the mammary immune system to establish an effective response to Staphylococcus aureus infections.

Immunosuppression by T regulatory cells in cows infected with Staphylococcal superantigen

Our recent study has provided that the in vitro SEC-induced proliferation of bovine T cells is preceded by a period of a non-proliferative immunoregulation of T cells that may be associated with cytokine production regulated by type 1 or type 2 T cells. Inversion of CD4+:CD8+ T cell ratio and induction of CD8+T cells with immunoregulatory activity could increase the probability of intracellular survival of Staphylococcus aureus (S. aureus). The increase of activated CD8+(ACT2+ BoCD8+) T cells in cows with mastitis caused by S. aureus may be associated with immune-regulatory function in the bovine mammary gland. The difference and similarity between bovine activated CD8+ T cells (CD8+ CD26+)and well-established human CD4+ CD25+ T regulatory (Tr)cells may help to reveal their unique immune regulatory system in the host infected with S. aureus.

Capsular polysaccharide typing of domestic mastitis-causing Staphylococcus aureus strains and its potential exploration of bovine mastitis vaccine developmen. I. capsular polysaccharide typing, isolation and purification of the strains

One hundred seven isolates of Staphylococcus aureus from bovine mastitis were investigated for colony morphology in serum-soft agar (SSA), autoagglutination in salt, and capsular serotype. Capsular polysaccharide (CP) was purified and quantified from the extracts of clinical isolates. Overall, 89 isolates (83.2%) were diffuse in the SSA, without any difference in the proportion of diffuse colony between type 5 and type 8 strains. Some strains exhibited compact colonies in the SSA and expressed CP as determined by an enzyme-linked immunosorbent assay, indicating that compact morphology does not exclude encapsulation. The majority of the strains (11/12) showed autoagglutination in the salt aggregation test. The serotype 336 accounted for 46.7% of the isolates followed by serotype 5 (12.1%) and serotype 8 (12.1%). Particularly, twenty-six (24.3%) isolates reacted with two serotypes; 7 for type 8/336 and 19 for type 5/336. Five isolates (4.7%) were nontypeable with monoclonal antibodies specific for CP serotype 5, 8, or 336. The CP concentration in culture supernatants varied with the serotypes, and the total amount of CP produced by cells grown in a liquid medium was much less than that produced by cells grown on a solid medium. The Western blotting indicated that the CP bands of S. aureus serotype 5 and 8 were ranged in the molecular mass of 58-84 kilodalton (kDa), with additional bands in the region of approximately >or= 48 or

Hyperimmunoglobulin E-recurrent infection syndrome in a patient with juvenile dermatomyositis

A 13-year-old girl presented with multiple skin abscesses. She was diagnosed as having juvenile dermatomyositis (DM) at the age of 7 years. She had suffered from recurrent skin infections, atypical pruritic dermatitis and pneumonia since the age of 8 years. Bacteriologic and fungal cultures for skin abscesses and oral mucosa were positive S. aureus and C. albicans, respectively. Chemotactic defect in peripheral blood neutrophils was observed. The level of serum IgE was markedly elevated, and anti-S.aureus specific IgE was found. A diagnosis of hyperimmunoglobulin E-recurrent infection syndrome (HIE) was made and she was successfully treated with surgical drainage and antibiotics. To our knowledge, this is the first case report of HIE in a patient with juvenile dermatomyositis.

Species distribution of clinical isolates of Staphylococci.

Species identification of 103 strains of staphylococci isolated from various clinical specimens revealed as many as eight species. S. aureus was the commonest isolate (57.28%) followed by S. epidermidis (17.47%). S. hominis (8.73%), S. saprophyticus (6.79%), S. intermedius, S. capitis and S. cohni (1.94% each) in decreasing order. They were mostly isolated from pus (41.74%) followed by urine (22.33%) and blood (18.44%) accordingly. Of the total isolates, 65 were coagulase positive while 38 isolates were coagulase negative. Phase typing of S. aureus strains revealed that 49 isolates were typable of which 17 isolates belonged to phase group III, 16 to phase group 1, 4 to group II and 3 belonged to group V while 9 strains could not be grouped. The antibiotic resistance pattern showed maximum resistance to penicillin (63.10%) while resistance was minimum with gentamycin (8.73%). Resistance to ampicillin (51.45%), cephazoline (51.45%), erythromycin (31.06+) and cloxacillin (18.44%) was low to moderate. The increasing recognition of pathogenic potential of various species of staphylococci and emergence of drug resistance amongst them denotes the need to adopt better laboratory procedures to identify and understand the diversity of staphylococci isolated from clinical material.

Purification of Staphylococcal enterotoxins B and C2, by dye ligand chromatography - production of antisera

As enterotoxinas estafilocócicas B e C2 foram purificadas a partir do sobrenadante de culturas, através de cromatografia de troca catiônica em resina Amberlite CG-50 e cromatografia de afinidade com o corante Red A. Cem mililitros de sobrenadante de culturas contendo 270 mg de SEB/ml e 150 ml de sobrenadante contendo 93 mg de SEC2/ml proporcionaram uma recuperaçäo final de 59 por cento e 42 por cento, respectivamente. As toxinas purificadas apresentaram-se homogêneas quando analisadas por eletroforese em gel de poliacrilamida dodecil-sulfato de sódio. A imunizaçäo de coelhos com as enterotoxinas purificadas forneceram títulos máximos de 80 para a enterotoxina B e 40 para a enterotoxina C2. A metodologia descrita neste trabalho mostrou-se adequada para a purificaçäo de enterotoxinas B e C2, visando a obtençäo de reagentes e produçäo de anticorpos específicos, utilizando pequenos volumes iniciais de sobrenadante de culturas

Estafilococos resistentes à Oxacilina säo encontrados entre portadores da comunidade? / Are there oxacilin resistent staphilococci among carriers in the communitty?

O objetivo deste trabalho é investigar a existência de estafilococos resistentes à oxacilina entre portadores da comunicade. Para tanto, estudamos amostras obtidas de 93 estudantes de medicina näo expostos ao ambiente hospitalar. Dois testes laboratoriais foram empregados para detecçäo de resistência à oxacilina: teste de difusäo em ágar e teste de triagem com meio salino. Isolou-se Staphylococcus aureus em 21 (22,6 por cento) dos estudantes, näo tendo sido observada resistência a oxacilina. Em três estudantes encontramos estafilococos coagulares negativos apresentando resistência a oxacilina. Os dois testes laboratoriais usados na detecçäo de resistência apresentaram boa correlaçäo. Os dados obtidos apoiam o uso de oxacilina para tratamento de estafilococcias adquiridas na comunidade

Endocardite infecciosa e alteraçöes renais / Infectious endocarditis and renal alterations

Säo discutidos os principais fenômenos imunológicos observados na endocardite infecciosa, com ênfase dada às lesöes renais, que têm sido as mais estudads, entre as de natureza imunológica nesta patologia

Hypersensitivity responses to Staphylococcus aureus infections in rabbits. An experimental study.

Repeated weekly infections with S aureus, of bovine mammary origin, for three times evoked an immediate and a delayed type hypersensitivity in rabbits. The skin responses at 6 hr were characterized by oedema, haemorrhages and infiltration of polymorphonuclear cells. While at 24 hr it was dominated by mononuclear cells specially lymphocytes in the dermis.

Acute haematogenous osteomyelitis and ABO blood groups and secretor status

An association between the incidence of AHO and ABO blood groups was established. The secretory junction of the saliva had no such correlation. AHO is more common among children of blood Group O and, to a lesser extent, Group A. Although it was found to occur more commonly among secretors than non-secretors, the difference from a control group was not statistically significant. At present this possibility can only be taken as a tentatative suggestion for further research in this field