Staphylococcus aureus is one of the principal human pathogens that colonize healthy individuals in the community in general, and it is responsible for severe infections in hospitalized patients. Due to an increase in the prevalence of strains of methicillin-resistant S. aureus (MRSA), combating these microorganisms has become increasingly difficult. A descriptive study was carried out on 231 patients in intensive care at the Oswaldo Cruz University Hospital (HUOC) in Recife, Brazil between January and April 2003 to determine the prevalence of S. aureus and MRSA and to evaluate risk factors for colonization by these bacteria when introduced into Intensive Care Units (ICUs). Body secretions were collected from the nostrils, axillary and perineal regions, and from broken skin lesions, of all patients during the first 48 hours following admission to the ICU. Samples were inoculated into blood agar and mannitol-salt-agar culture medium and identified by Gram staining, and by coagulase, DNAse and agglutination (Slidex Staph Test®) tests. Growth in Mueller-Hinton agar with 4% sodium chloride and 6mg/L oxacillin was used to identify MRSA. In addition, the latex agglutination test was performed to identify penicillin-binding protein, PBP 2A. The prevalence of S. aureus and MRSA was 87/231 (37.7%) and 30/231 (12.98%), respectively. There was no association between any risk factor studied (age, sex, origin of the patient -whether hospital or community, previous hospitalization, use of current or previous antibiotic therapy, corticotherapy and/or immunotherapy, reason for hospitalization and place of hospitalization) and the presence of S. aureus. However, a significant association was established between previous hospitalization and the presence of MRSA (RR:1.85; CI:1.00-3.41; p=0.041). The nostrils were the principal site of colonization by both S. aureus (80.4%) and MRSA (26.4%), followed by the perineal area, with rates of 27.6% and 12.6%, respectively. If only the nostrils had been investigated, the study would have failed to diagnose 17 patients (19.5%) as carriers of the pathogen into the ICU, thus contributing towards cross-dissemination.

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O Staphylococcus aureus é um dos principais patógenos que coloniza indivíduos saudáveis na comunidade e responde por infecções em pacientes hospitalizados. Um estudo transversal foi realizado para determinar a prevalência de S. aureus meticilina-resistente e sensível entre 231 pacientes, internados entre janeiro e abril de 2003, nas unidades de terapia intensiva (UTIs) do Hospital Universitário Oswaldo Cruz, assim como os possíveis fatores associados à colonização. Foram coletadas secreções de narinas, axilas, região perineal e dermatoses com soluções de continuidade, de todos os pacientes, nas primeiras 48 horas de internamento nas UTIs. O material foi semeado em meios de cultura adequados. A prevalência de S. aureus igualou-se a 37,7% (87/231), sendo 13% (30/231) meticilina-resistente e 24,8% (57/231) meticilina-sensível. Idade, sexo, uso de antibioticoterapia, corticoterapia, motivo e local do internamento não se associaram à presença do S. aureus ou do meticilina-resistente. Houve associação significante entre procedência hospitalar e colonização por S. aureus, independente da cepa, e entre internamento anterior e presença do S. aureus meticilina-resistente. As narinas foram o sítio de colonização mais significante, por S. aureus meticilina-resistente (47/57=82,4%) e sensível (23/30=76,7%). Foi alta a prevalência do S. aureus (meticilina resistente ou sensível), assim como do meticilina-resistente entre os pacientes das UTIs deste hospital. Estudos futuros poderão comprovar se os resultados aqui descritos e medidas de rastreamento para S. aureus poderiam ser adotadas, de forma prospectiva, para se avaliar o risco, assim como a magnitude do efeito, no controle de infecções hospitalares provocadas por estes patógenos.

Objectives Many African countries have reported fewer COVID-19 cases than countries elsewhere. By the end of 2020, Guinea-Bissau, West Africa, had <2500 PCR-confirmed cases corresponding to 0.1% of the ∼1.8 million national population. We assessed the prevalence of SARS-CoV-2 antibodies in urban Guinea-Bissau to help guide the pandemic response in Guinea-Bissau. Study design Cross-sectional assessment of SARS-CoV-2 antibody in a cohort of staff at the Bandim Health Project. Methods We measured IgG antibodies using point-of-care rapid tests among 140 staff and associates at a biometric research field station in Bissau, the capital of Guinea-Bissau, during November 2020. Results Of 140 participants, 25 (18%) were IgG-positive. Among IgG-positives, 12 (48%) reported an episode of illness since the onset of the pandemic. Twenty-five (18%) participants had been PCR-tested between May and September; 7 (28%) had been PCR-positive. Four of these seven tested IgG-negative in the present study. Five participants reported that somebody had died in their house, corresponding crudely to an annual death rate of 4.5/1000 people; no death was attributed to COVID-19. Outdoor workers had a lower prevalence of IgG-positivity. Conclusions In spite of the low official number of COVID-19 cases, our serosurvey found a high prevalence of IgG-positivity. Most IgG-positives had not been ill. The official number of PCR-confirmed COVID-19 cases has thus grossly underestimated the prevalence of COVID-19 during the pandemic. The observed overall mortality rate in households of Bandim Health Project employees was not higher than the official Guinean mortality rate of 9.6/1000 people.

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