Frequency, spatial distribution, and genetic diversity of Blastocystis among referred individuals to a clinical laboratory: First report of subtype 9 in Brazil

The enteric protist Blastocystis has a worldwide distribution, however its prevalence in the human population is still underestimated, especially in developing countries where proper diagnosis is not performed in the routine of clinical laboratories. In this study, we aimed to assess the frequency, genetic diversity, and spatial distribution of Blastocystis isolates detected in fecal samples referred to a clinical laboratory for routine examination in inner São Paulo State, Brazil. A total of 348 leftover stool samples available for disposal from female and male individuals with age ranging from 3 months to 88 years were analyzed by both microscopic examination and PCR/sequencing of the SSU rRNA gene. The overall frequency of Blastocystis sp. was 31% (108/348), including 20.1% (70/348) and 31% (108/348) by microscopic examination and PCR/sequencing, respectively. Significant association was found only between Blastocystis infection and age, since the highest rate of positive samples was detected among 5-9 years old individuals (p < 0.0001). In addition, spatial distribution revealed a wide distribution of the positive samples, however they were densely concentrated in more populated areas. Seven subtypes were identified, namely ST1 (40.7%), ST2 (9.2%), ST3 (45.3%), ST4 (0.9%), ST6 (1.8%), ST7 (0.9%) and ST9 (0.9%). The intra-subtype analysis revealed a total of 25 different alleles previously reported. Here, the findings lead us to highlight the following aspects: (1) the identification of a ST9 isolate is a relevant finding since it is considered a very rare subtype in human infections as well as this is the first report in Brazil; (2) the high frequency of Blastocystis in fecal samples submitted for examination in a clinical laboratory points to the need to consider its search in routine parasitological examinations, (3) the spatial distribution of Blastocystis infection was not homogeneous but concentrated in more populated areas where the access for population to diagnostic services in healthcare is likely to be easier and, (4) the genetic variability of Blastocystis isolates suggests exposure of inhabitants living in inner municipalities to different sources of contamination involving anthroponotic and zoonotic transmission pathways.

Predictors of development of cardiac and digestive disorders among patients with indeterminate chronic Chagas Disease

American trypanosomiasis (Chagas disease, CD) affects circa 7 million persons worldwide. While of those persons present the asymptomatic, indeterminate chronic form (ICF), many will eventually progress to cardiac or digestive disorders. We studied a nonconcurrent (retrospective) cohort of patients attending an outpatient CD clinic in Southeastern Brazil, who were admitted while presenting the ICF in the period from 1998 through 2018 and followed until 2019. The outcomes of interest were the progression to cardiac or digestive CD forms. We were also interested in analyzing the impact of Benznidazole therapy on the progression of the disease. Extensive review of medical charts and laboratory files was conducted, collecting data up to year 2019. Demographics (upon inclusion), body mass index, comorbidities (including the Charlson index) and use of Benznidazole were recorded. The outcomes were defined by abnormalities in those test that could not be attributed to other causes. Statistical analysis included univariate and multivariable Cox regression models. Among 379 subjects included in the study, 87 (22.9%) and 100 (26.4%) progressed to cardiac and digestive forms, respectively. In the final multivariable model, cardiac disorders were positively associated with previous coronary syndrome (Hazzard Ratio [HR], 2.42; 95% Confidence Interval [CI], 1.53-3.81) and negatively associated with Benznidazole therapy (HR, 0.26; 95%CI, 0.11-0.60). On the other hand, female gender was the only independent predictor of progression to digestive forms (HR, 1.56; 95%CI, 1.03-2.38). Our results point to the impact of comorbidities on progression do cardiac CD, with possible benefit of the use of Benznidazole.

Risk factors for leptospirosis and brucellosis in people living with human immunodeficiency virus who attended a referral hospital in southeastern Brazil

INTRODUCTION:

Leptospirosis and brucellosis cause immunosuppression that worsens the clinical condition of people living with HIV/AIDS (PLWHA). We investigated the serological profile and risk factors of PLWHA.

METHODS:

Serum samples (n=238) were researched for Brucella spp. antibodies using Rose Bengal and tube agglutination tests and Leptospira spp. antibodies using the microscopic agglutination test.

RESULTS:

All samples were negative for Brucella spp. For leptospirosis, four samples (1.69%) were positive, and Andamana was the prevalent serovar.

CONCLUSIONS:

Low or no detection of these zoonoses does not reduce their importance in PLWHA. Vigilant, educational, and preventive measures should be adopted.

Predictors of relapse of visceral leishmaniasis in inner São Paulo State, Brazil

OBJECTIVES

Visceral leishmaniasis (VL) is a public health threat for several tropical countries, including Brazil. Therapy failures and relapses aggravate VL morbidity and mortality. Our study aimed at identifying predictors of relapse and thus contributes to directing therapeutic options and patient follow-up.

METHODS

A nonconcurrent cohort of 571 subjects who completed successful therapy for VL in the city of Bauru, São Paulo State, Brazil, was followed for 24 months in order to identify the incidence and predictors of relapse. Extensive review of medical charts and laboratory files was conducted. Univariate and multivariable Cox regression models were used to identify predictors for the outcome of interest. A hierarchical strategy was used for variable selection in multivariable models.

RESULTS

Relapses occurred in 6.8% of treated subjects, after a median of 6 months (interquartile range, 4-9). In a comprehensive multivariable model, relapse was associated with: HIV-coinfection (hazard ratio [HR], 7.47; 95% confidence interval [CI], 2.58-21.55); the presence of lower limb edema (HR, 6.06; 95%CI, 1.38-26.77) and low platelet count upon admission (HR for platelet count × 1000, 0.99; 95%CI, 0.98-0.99) ; and secondary pneumonia (HR, 5.49; 95%CI, 1.49-20.18). On the other hand, therapy with Liposomal Amphotericin (as opposed to Antimoniate) was not independently associated with relapse (HR, 5.97; 95%CI, 0.63-56.29).

CONCLUSION

Besides reinforcing the impact of HIV coinfection on the outcome of VL, our study points to clinical and laboratory findings that characterize patients who were more likely to relapse. Those groups should be more closely followed, and possibly could benefit from novel therapeutic options.

Molecular epidemiology of methicillin-resistant Staphylococcus aureus in the Brazilian primary health care system

OBJECTIVE

To evaluate the molecular epidemiology and to georeference Staphylococcus aureus isolated from wounds and nares of patients seen at Basic Health Units (BHUs) of a Brazilian city.

METHODS

Observational, cross-sectional study conducted from 2010 to 2013. A total of 119 S. aureus strains isolated from the wounds and nares of 88 patients were studied. The isolates were characterised by identifying virulence genes encoding enterotoxins A-E, haemolysins α, β and δ, exfoliatins A, B and D, biofilm production, Panton-Valentine Leukocidin and toxic shock syndrome toxin 1, and by pulsed-field gel electrophoresis (PFGE), multilocus sequence and spa typing.

RESULTS

Eighteen methicillin-resistant Staphylococcus aureus (MRSA) (6 SCCmec type II and 12 SCCmec type IV) and 101 (85%) MSSA were identified. PFGE typing resulted in the formation of eight clusters, with STs 1, 5, 8, 30, 188, 1176 and 1635 and spa type t002 being the predominant types among MSSA. The 18 MRSA belonged to STs 5, 8 and 1176 and spa types t002 and t062.

CONCLUSION

The results demonstrate widespread dissemination of MSSA and MRSA clones carrying haemolysin, biofilm and toxin genes. Kernel density estimation revealed the highest density of S. aureus in the 4, 5 and 8 BHUs.

Fatores de virulência em linhagens de Escherichia coli isoladas de mastite bovina

Avaliou-se a ocorrência de fatores de virulência e do sorotipo O157:H7 em 120 linhagens de Escherichia coli, isoladas de 80 casos de mastite clínica bovina e 40 de mastite subclínica. Verificou-se alfa-hemolisina em oito (6,7%) linhagens, isoladas de cinco casos de mastite clínica e três de mastite subclínica e em nenhuma das estirpes detectou-se enteroemolisina. A presença de sideróforos foi encontrada em 11 (9,2%) linhagens, sete de mastite clínica e quatro de subclínica. Em duas (1,7%) estirpes isoladas de mastite subclínica, identificou-se enterotoxina STa. Observou-se efeito citopático em células vero compatível com a produção de verotoxina-VT em cinco (4,2%) linhagens, duas de mastite clínica e três subclínicas. Em uma (0,8%) linhagem isolada de mastite clínica, detectou-se efeito citopático compatível com o fator necrosante citotóxico. Nenhuma estirpe apresentou-se sorbitol-negativa no MacConkey-sorbitol, tampouco aglutinou com o sorotipo O157:H7. Os antimicrobianos mais efetivos foram polimixina B (97,5%) e norfloxacina (95,8%). Observou-se multi-resistência a dois ou mais antimicrobianos em 24 (20%) estirpes, principalmente com o uso de ampicilina e ceftiofur.

Pheno and genotyping ofStaphylococcus aureus, isolated from bovine milk samples from São Paulo State, Brazil

In the present study, 87 Staphylococcus aureus isolates obtained from milk samples of 87 cows with mastitis in 6 different municipal districts of 2 regions of São Paulo State, Brazil, were compared pheno and genotypically. Pulsed-field gel electrophoresis (PFGE) analysis of the strains was performed, and PCR was carried out to detect genes for a number of staphylococcal cell surface proteins, exoproteins, and 3 classes of agr genes. Nine distinct S. aureus lineages (LA–LI) were identified by PFGE. The lineages LA and LE, which accounted together for 63 strains (72.2%), were prevalent and had been collected from all of the 6 municipal districts, indicating a broad geographic distribution of these lineages; LB, LC, LD, LF, LG, LH, and LI, however, were isolated sporadically and accounted for 24 strains (27.8%). Some characteristics, like penicillin resistance and the presence of cap8 and agr class II genes, were associated with the prevalent lineages (LA and LE), and penicillin susceptibility and the presence of cna and cap5 genes were associated with sporadic lineages. According to the present results, some S. aureus lineages possess a combination of genes that confer the propensity to cause and disseminate infection, and only a limited number of clones are responsible for the cases of bovine mastitis on the various farms.Key words: S. aureus, mastitis, phenotyping, genotyping.