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

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

ACOMETIMENTO DO APÊNDICE CECAL NA PARACOCCIDIOMICOSE: RELATO DE CASO

Introdução: A Paracoccidiomicose (PCM) é uma micose sistêmica endêmica do Brasil. Na Forma Aguda/subaguda (FA) os órgãos do sistema fagocítico-monocitário são afetados, principalmente os linfonodos, medula óssea, fígado e baço. O acometimento do apêndice cecal, que é um órgão linfoide, tem sido pouco descrito na literatura e o seu diagnóstico representa um desafio. Objetivo: Relatar um caso de FA da PCM em paciente jovem que apresentou acometimento do apêndice cecal por Paracoccidioides. Relato de caso: Homem, 20 anos, natural e procedente de Campo Grande/MS. Apresentava à admissão linfonodomegalia generalizada há 3 meses, associada a perda ponderal de nove quilos em três meses. Uma semana antes apresentou picos febris de 38° em média, associados a fadiga, odinofagia e hiporexia. Negava comorbidades. Ao exame físico apresentava-se com 51 Kg, palidez cutâneo-mucosa e com linfonodomegalia em cadeias linfonodais pré-auricular bilateral, retroauricular bilaterais, occipital direito, cervical superficial e profundo bilateral, tonsilar bilateral, subclavicular bilateral, submentoniano, axilar bilateral e inguinal bilateral, em sua maioria de tamanhos de aproximadamente 1 a 2 cm dolorosos e imóveis. Leveduras com características de Paracoccidioides sp foram visualizadas no exame micológico direto e no histopatológico do fragmento de linfonodo biopsiado. A pesquisa de anticorpos anti-Paracoccidioides por imunodifusão dupla foi reagente, com titulação 1:64. Foi iniciado tratamento com sulfametoxazol + trimetoprima (CMX) 800+160 mg de 8/8h e o paciente teve alta hospitalar. Um mês depois, após um período de melhora clínica, voltou a piorar e apresentar dor abdominal importante, foi indicada anfotericina B formulação lipídica (AnfoB_L) na dose de 150 mg/dia. Evoluiu com piora da dor abdominal, localizando em região inguinal direita. A ultrassonografia sugeriu apendicite aguda. Foi feita apendicectomia e lavagem da cavidade abdominal sem intercorrências. O exame histopatológico foi conclusivo de apendicite aguda granulomatosa por Paracoccidioides spp., visualizados pela coloração de metenamina de prata de Grocott-Gomori. Após completar 1,5g de AnfoB_L, foi prescrito CMX e evoluiu com muita melhora clínica. Conclusão: O caso ilustra a importância de se considerar a PCM no diagnóstico diferencial de abdome agudo em áreas endêmicas da doença

Iron metabolism disorders of patients with chronic paracoccidioidomycosis

Paracoccidioidomycosis (PCM) is caused by Paracoccidioides spp.; during infection, some host mechanisms limit the availability of iron, thereby reducing its reproduction. However, Paracoccidioides spp. can evade the immune defense and, even under limited iron conditions, use this mineral for growth and dissemination. This study evaluated the iron metabolism of 39 patients who were diagnosed with chronic PCM from 2013 to 2021. The forms of iron before treatment and at the time of clinical cure were evaluated based on the following: serum ferritin levels (storage iron); total iron-binding capacity (TIBC) and transferrin saturation (TSAT) level (transport iron); red blood cell (RBC), hemoglobin (Hb), hematocrit (HCT), and soluble transferrin receptor (sTfR) levels; and sTfR/log ferritin ratio (functional iron). The mean age of the patients was 54.5 years (±6.7 years). Most patients were men (97.4%), rural workers (92.1%), and smokers (84.6%); furthermore, most had moderate disease severity (66.7%). After achieving clinical cure, we observed that serum ferritin levels decreased, and parameters of functional iron increased. The extent of alteration in these parameters were more pronounced in severe cases than in to mild or moderate cases. Furthermore, moderate correlations were observed between C-reactive protein and the Hb (r = -0.500; p = 0.002), RBC (r = -0.461; p = 0.005), HCT (r = -0.514; p = 0.001), and iron levels (r = -0.491; p = 0.002). However, it is possible to infer that PCM interferes with functional and storage iron because improvements in these parameters after treatment as well as associations with disease severity were observed. PCM can lead to anemia of inflammation, which can be differentiated from iron deficiency anemia by a careful investigation of the iron form parameters

Characterisation of microbial attack on archaeological bone

As part of an EU funded project to investigate the factors influencing bone preservation in the archaeological record, more than 250 bones from 41 archaeological sites in five countries spanning four climatic regions were studied for diagenetic alteration. Sites were selected to cover a range of environmental conditions and archaeological contexts. Microscopic and physical (mercury intrusion porosimetry) analyses of these bones revealed that the majority (68%) had suffered microbial attack. Furthermore, significant differences were found between animal and human bone in both the state of preservation and the type of microbial attack present. These differences in preservation might result from differences in early taphonomy of the bones. © 2003 Elsevier Science Ltd. All rights reserved