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.

Isoenzyme genotyping and phylogenetic analysis of oxacillin-resistance Staphylococcus aureus isolates

Aim: The propagation of S. aureus in hospital and dental environments is considered an important public health problem since resistant strains can cause serious infections in humans. The genetic variability of 99 oxacillin-resistant S. aureus isolates (ORSA) from the dental patients (oral cavity) and environments (air) was studied by isoenzyme genotyping. Methods: S. aureus isolates were studied using isoenzyme markers (alcohol dehydrogenase, sorbitol dehydrogenase, mannitol-1-phosphate dehydrogenase, malate dehydrogenase, glucose dehydrogenase, D-galactose dehydrogenase, glucose-6-phosphate dehydrogenase, catalase and α/ß-esterase) and genetic (Nei's statistics) and cluster analysis (UPGMA algorithm). Results: A highly frequent polyclonal pattern was observed in this population of ORSA isolates, suggesting various sources of contamination or microbial dispersion. Genetic relationship analysis showed a high degree of polymorphism between the strains, and it revealed three taxa (A, B and C) distantly genetically related (0.653≤dij≤1.432) and fifteen clusters (I to XV) moderately related (0.282≤dij<0.653). These clusters harbored two or more highly related strains (0≤dij<0.282), and the existence of microevolutionary processes in the population of ORSA. Conclusion: This research reinforces the hypothesis of the existence of several sources of contamination and/or dispersal of ORSA of clinical and epidemiologically importance, which could be associated with carriers (patients) and dental environmental (air) (AU)

ALDH1 and CD44 immunoexpression as prognostic indicators of invasion and metastasis in oral squamous cell carcinoma / Immunoexpressão de ALDH1 e CD44 como indicador de prognóstico de invasão e metástase em carcinoma epidermoide de boca

Oral squamous cell carcinoma (OSCC) is one of the most common cancer in the head and neck and results in high morbidity and mortality annually, being the worst prognosis related to the presence of metastasis in cervical lymph nodes. Metastasis has been associated with a subpopulation of tumor cells, called cancer stem cells (CSCs), which consists of a small population with stem-like cells properties, higher rate of migration and metastatic potential compared to other ordinary tumor cells from the tumor bulk. The aim of present study was to evaluate the immunoexpression of the CSC markers ALDH1 and CD44 in primary sites of OSCC and corresponding metastatic lymph nodes, by means of immunohistochemistry. The immunolabeling was further correlated with clinicopathological data. Archived Formalin-fixed, Paraffin-embedded tumor tissue specimens (n=50) and corresponding metastatic lymph nodes (n=25) were obtained from 50 patients with OSCC after surgical treatment. CD44 and ALDH1 immunostaining were semi-quantitatively scored according to the proportion and intensity of positive cells within the invasive front and metastatic cervical lymph nodes as a whole. The percentage of ALDH1 and CD44 positive tumor cells as well as immunostaining intensity was graded and a combined score, ranging from 0 to 9 (ALDH1) or 0 to 12 (CD44), was obtained by multiplying both parameters. Next, combined scores were dichotomized into a final score classified as low (ALDH1≤ 2; CD44≤ 4) or high (ALDH1> 2; CD44> 4) immunoexpression. ALDH1 and CD44 immunoexpression was detected in both primary and metastatic tumor sites, although with different immunolabeling pattern. ALDH1-positive tumor cells consisted of scattered patches and no immunoexpression was observed within keratin pearls. Conversely, CD44 immunopositivity was more homogeneous and widely distributed, with higher labeling in peripheral areas of the tumor islands within the tumor invasion front. Although not statistically significant, the means of ALDH1high (p= 0.0985) and CD44high (p= 0.1632; Mann- Whitney post-test) immunoexpression were higher in metastatic lymph nodes compared to primary tumors. ALDH1high was positively associated (p= 0.0184) with perivascular invasion, while CD44high was positively associated (p= 0.0186; Fisher's Exact Test) with metastasis (N+). Five-year survival rates tended to be lower in patients with ALDH1high immunoexpression compared to ALDH1low, although with no statistical significance (p= 0.1303). In summary, the present study revealed that CD44 is highly labeled in tumor cell from metastatic sites, being associated with lymph node metastasis, while ALDH1 high immunostaining was associated with perivascular invasion. Altogether, it suggests that immunoexpression of CD44 and ALDH1 links the cancer stem cell phenotype with OSCC invasion and metastasis.(AU)

O carcinoma epidermóide de boca (CEB) é uma das neoplasias mais comuns da região de cabeça e pescoço e resulta em alta morbidade e mortalidade anualmente, estando o pior prognóstico relacionado à presença de metástase em linfonodos cervicais. O processo de metástase tem sido associado a uma subpopulação de células tumorais, chamadas células-tronco de câncer (CSC, do inglês Cancer stem cells), que consistem em uma pequena população de células com propriedades de células-tronco, incluindo maior taxa de migração e potencial metastático em comparação com outras células tumorais. O objetivo do presente estudo foi avaliar os marcadores candidatos de CSCs ALDH1 e CD44 em tumores primários de CEB e metástases linfonodais correspondentes, por meio de imuno-histoquímica. A imunomarcação foi posteriormente correlacionada com dados clínico-patológicos. Foram obtidas amostras de tecido tumoral parafinado fixado em formalina (n = 50) e os linfonodos metastáticos correspondentes (n = 25) de 50 pacientes com CEB submetidos somente ao tratamento cirúrgico. Os marcadores CD44 e ALDH1 foram analisados de forma semi-quantitativa de acordo com a proporção e intensidade de células positivas no fronte de invasão e em linfonodos cervicais metastáticos como um todo. A porcentagem de células tumorais ALDH1 e CD44 positivas, bem como a intensidade da imunomarcação, foi classificada em um escore combinado obtido pela multiplicação de ambos os parâmetros, variando de 0 a 9 (ALDH1) ou 0 a 12 (CD44). Em seguida, as pontuações combinadas foram dicotomizadas em um escore final classificado como baixo (do inglês low) (ALDH1 ≤ 2; CD44 ≤ 4) ou alto (do inglês high) (ALDH1> 2; CD44> 4). A imunoexpressão de ALDH1 e CD44 foi detectada tanto em tumores primários quanto em linfonodos cervicais metastáticos, embora com padrão diferente de imunomarcação. Células tumorais ALDH1-positivas foram identificadas como focais e dispersas ao longo do fronte de invasão, sem imunomarcação nas pérolas córneas. Em contraste, a imunopositividade para CD44 foi mais homogênea e amplamente distribuída, com maior imunomarcação em áreas periféricas das ilhotas tumorais presentes no fronte de invasão. Embora não estatisticamente significativa, as médias da imunoexpressão ALDH1high (p = 0.0985) e CD44high (p = 0.1632, pós-teste de Mann-Whitney) foram maiores em linfonodos metastáticos em comparação com tumores primários. ALDH1high foi positivamente associado com invasão perivascular (p = 0.0184), enquanto CD44high foi com metástase (N+) (p = 0.0186; teste exato de Fisher). As taxas de sobrevida global em 5 anos tenderam a ser mais baixas em pacientes com imunoexpressão elevada de ALDH1 em comparação com ALDH1low, embora sem significância estatística (p = 0.1303). Em resumo, o presente estudo revelou que a elevada imunomarcação de CD44 está significativamente associada com metástases linfonodais, enquanto que a elevada imunomarcação de ALDH1 está associada com invasão perivascular. Em conjunto, sugerimos que a imunoexpressão de CD44 e ALDH1 esteja relacionada com o fenótipo de células tronco de câncer que tem capacidade de invasão e metástase em CEB.(AU)