Molecular characterization of methicillin-resistant Staphylococcus aureus among insulin-dependent diabetic individuals in Brazil

BACKGROUND

People with diabetes mellitus, especially insulin-dependent diabetic patients, are a risk group for staphylococcal infections. Asymptomatic infection with Staphylococcus aureus is common and favors dissemination of the microorganism, rendering these individuals a source of infection. This study aimed to characterize the resistance profile, clonal profile and sequence type, as well as to analyze the prevalence and risk factors for nasal and oropharyngeal carriage of methicillin-susceptible (MSSA) and methicillin-resistant S. aureus (MRSA) isolated from insulin-dependent diabetic individuals in the city of Botucatu, SP, Brazil.

METHODS

Staphylococcus aureus was collected from the nasopharynx and oropharynx of 312 community-dwelling insulin-dependent diabetic individuals over a period of 3 years (October 2015 to December 2018). The isolates were characterized by susceptibility profiling, detection of the mecA gene, SCCmec typing, and molecular typing by PFGE and MLST. The risk factors associated with S. aureus and MRSA carriage were determined by logistic regression analysis.

RESULTS

The overall prevalence of colonization with S. aureus and MRSA was 30.4% and 4.8%, respectively. Fifteen of the 112 S. aureus isolates carried the mecA gene; SCCmec type IV was identified in 10 isolates, SCCmec type I in three, and SCCmec type II in two. Among the 15 resistant isolates (MRSA), four were susceptible to oxacillin/cefoxitin by the disc diffusion method and one MSSA isolate was resistant to sulfamethoxazole/trimethoprim. The analysis of risk factors revealed a protective effect of age and lung disease, while lower-extremity ulcers were a risk factor for S. aureus. For MRSA, only male gender was significantly associated as a risk factor in multivariate analysis. Clonal profile analysis demonstrated the formation of clusters among MRSA isolates from different patients, with the identification of ST5-IV, ST5-I, and ST8-IV. Isolates carrying ST398 were identified among MSSA and MRSA (ST398-IV).

CONCLUSION

Our findings reinforce the importance of epidemiological studies of S. aureus carriage, especially in populations at high risk of infections such as diabetics. The data suggest widespread dissemination of MRSA in the population of insulin-dependent diabetic patients studied, as well as the emergence of important lineages among these individuals.

The use of health geography modeling to understand early dispersion of COVID-19 in São Paulo, Brazil

Public health policies to contain the spread of COVID-19 rely mainly on non-pharmacological measures. Those measures, especially social distancing, are a challenge for developing countries, such as Brazil. In São Paulo, the most populous state in Brazil (45 million inhabitants), most COVID-19 cases up to April 18th were reported in the Capital and metropolitan area. However, the inner municipalities, where 20 million people live, are also at risk. As governmental authorities discuss the loosening of measures for restricting population mobility, it is urgent to analyze the routes of dispersion of COVID-19 in São Paulo territory. We hypothesize that urban hierarchy is the main responsible for the disease spreading, and we identify the hotspots and the main routes of virus movement from the metropolis to the inner state. In this ecological study, we use geographic models of population mobility to check for patterns for the spread of SARS-CoV-2 infection. We identify two patterns based on surveillance data: one by contiguous diffusion from the capital metropolitan area, and the other hierarchical with long-distance spread through major highways that connects São Paulo city with cities of regional relevance. This knowledge can provide real-time responses to support public health strategies, optimizing the use of resources in order to minimize disease impact on population and economy.

COVID-19: What we talk about when we talk about masks

Even though most current recommendations include the general use of masks to prevent community transmission of SARS-Cov-2, the effectiveness of this measure is still debated. The studies on this policy include physical filtering tests with inanimate microparticles, randomized clinical trials, observational studies, ecological analyses, and even computational modeling of epidemics. Much of the so-called evidence is inferred from studies on different respiratory viruses and epidemiological settings. Heterogeneity is a major factor limiting the generalization of inferences. In this article, we reviewed the empirical and rational bases of mask use and how to understand these recommendations compared to other policies of social distancing, restrictions on non-essential services, and lockdown. We conclude that recent studies suggest a synergistic effect of the use of masks and social distancing rather than opposing effects of the two recommendations. Developing social communication approaches that clarify the need to combine different strategies is a challenge for public health authorities.

Evidence, rationality, and ignorance: Agnotological issues in COVID-19 science

Two decades ago, Robert Proctor coined the term agnotology to refer to the study of ignorance that stems from scientific research. Amid the coronavirus disease pandemic, the world is witnessing the greatest natural experiment ever, and countries have adopted different response strategies. An evaluation of the effectiveness of different policies will play a valuable role in preparing for future public health emergencies. However, controversial issues such as the timing and pathways of viral emergence, the effectiveness of social distancing and lockdown strategies, and the use of antimalarial drugs as therapy have still not been fully resolved. This serves as a fertile breeding ground for agnotological strategies, whereby scientific studies are deliberately or unintentionally designed to create distractions or draw conclusions that are not supported by research findings. Researchers, public health authorities, and healthcare workers should be equipped to identify such agnotological strategies, distinguish them from scientific fraud, and avoid drawing misleading inferences based on an irrational adherence to hypotheses and a lack of criticism of implausible results.

Increasing molecular diagnostic capacity and COVID-19 incidence in Brazil

Different countries have adopted strategies for the early detection of SARS-CoV-2 since the declaration of community transmission by the World Health Organization (WHO) and timely diagnosis has been considered one of the major obstacles for surveillance and healthcare. Here, we report the increase of the number of laboratories to COVID-19 diagnosis in Brazil. Our results demonstrate an increase and decentralisation of certified laboratories, which does not match the much higher increase in the number of COVID-19 cases. Also, it becomes clear that laboratories are irregularly distributed over the country, with a concentration in the most developed state, São Paulo.

Performance of rK39-based immunochromatographic rapid diagnostic test for serodiagnosis of visceral leishmaniasis using whole blood, serum and oral fluid

Background

The development of rK39-based immunochromatographic rapid diagnostic tests represents an important advance for serodiagnosis of visceral leishmaniasis, being cheap and easy to use at the point of care (POC). Although the use of rK39 have considerably improved the sensitivity and specificity of serological tests compared with total antigens, great variability in sensitivity and specificity was reported. This study aimed at the evaluation of “Kalazar Detect™ Rapid Test, Whole Blood” (Kalazar Detect RDT) for Visceral Leishmaniasis (VL) diagnosis using oral fluid, whole blood and serum specimens collected at different endemic areas of VL of Brazil.

Methodology

To evaluate Kalazar Detect RDT, oral fluid, whole blood and serum specimens from 128 VL patients, 85 healthy individuals, 22 patients with possible cross-reactivity diseases and 20 VL/aids coinfected patients were collected and assayed at the POC.

Principal findings and conclusions

The performance of Kalazar Detect RDT in whole blood and serum was similar; however, using oral fluid, the sensitivity was low. Particularly in samples from the city of Natal, Rio Grande do Norte state in Northeastern Brazil, we observed low sensitivity, 80.0% (95% CI: 62.7–90.5), using whole blood and serum, and poor sensitivity, 43.3% (95% CI: 27.4–60.8) with oral fluid. Those values were much lower than in the other regions, where sensitivity ranged from 92.7–96.3% in whole blood and serum, and 80.0–88.9% in oral fluid. Besides, in VL/aids coinfected patients, lower sensitivity was achieved compared with VL patients. In samples from Natal, the sensitivity was 0.0% (95% CI: 0.0–49.0) and 25.0% (95% CI: 4.6–69.9), using oral fluid and serum/whole blood, respectively; in samples from the other regions, the sensitivity ranged from 40.0–63.6% and 80.0–81.8%, respectively. As for specificity, high values were observed across the fluids, 100.0% (95% CI: 96.5–100.0) in whole blood, 96.3% (95% CI: 90.8–98.5) in serum, and 95.3% (95% CI: 89.5–98.0) in oral fluid; across localities, specificity ranged from 85.7–100.0%. Serum samples sent by the collaborating centers to Instituto de Medicina Tropical (n = 250) were tested by Kalazar Detect RDT, Direct Agglutination Test, Indirect immunofluorescence assay, Enzyme-linked immunosorbent assay, and IT-Leish® RDT. The regional difference in the performance of rK39-based RDT and lower sensitivity in Leishmania/HIV coinfected patients raise concern on the routine use of these products for the diagnosis of VL.

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.

Incidence and predictors of health care-associated infections among patients colonized with carbapenem-resistant Enterobacteriaceae

Colonization with carbapenem-resistant Enterobacteriaceae (CRE) precedes invasive infections. Neither the actual risk for the latter nor the route between the 2 stages is completely clear. We studied a retrospective cohort of patients hospitalized between 2013-2016 and colonized with CRE. The incidence of CRE health care-associated infections was 13.2%, and predictors were the presence of a urinary catheter and the use of carbapenems. Infection prevention strategies in CRE-colonized patients should focus on invasive devices and antimicrobial stewardship.

Impact of weather on the risk of surgical site infections in a tropical area

We studied the impact of average daily temperature and relative humidity on the risk of surgical site infections in 36,429 surgeries performed in a hospital in inner Brazil. Adjusted Poisson regression models found an association between surgical site infections and temperature (rate ratio [RR], 1.013; 95% confidence interval [CI], 1.001-1.025). The effect was concentrated on clean wound procedures and was greater over the 75th (RR, 1.109; 95% CI, 1.015-1.212) and 90th (RR, 1.196; 95% CI, 1.055-1.355) percentiles of daily temperature.

The role of intra and inter-hospital patient transfer in the dissemination of heathcare-associated multidrug-resistant pathogens

Healthcare-associated infections cause significant patient morbidity and mortality, and contribute to growing healthcare costs, whose effects may be felt most strongly in developing countries. Active surveillance systems, hospital staff compliance, including hand hygiene, and a rational use of antimicrobials are among the important measures to mitigate the spread of healthcare-associated infection within and between hospitals. Klebsiella pneumoniae is an important human pathogen that can spread in hospital settings, with some forms exhibiting drug resistance, including resistance to the carbapenem class of antibiotics, the drugs of last resort for such infections. Focusing on the role of patient movement within and between hospitals on the transmission and incidence of enterobacteria producing the K. pneumoniae Carbapenemase (KPC, an enzyme that inactivates several antimicrobials), we developed a metapopulation model where the connections among hospitals are made using a theoretical hospital network based on Brazilian hospital sizes and locations. The pathogen reproductive number, R₀ that measures the average number of new infections caused by a single infectious individual, was calculated in different scenarios defined by both the links between hospital environments (regular wards and intensive care units) and between different hospitals (patient transfer). Numerical simulation was used to illustrate the infection dynamics in this set of scenarios. The sensitivity of R₀ to model input parameters, such as hospital connectivity and patient-hospital staff contact rates was also established, highlighting the differential importance of factors amenable to change on pathogen transmission and control.

Nasal colonization with methicillin-resistant Staphylococcus aureus among elderly living in nursing homes in Brazil: risk factors and molecular epidemiology

BACKGROUND

Methicillin-resistant Staphylococcus aureus poses a threat to elderly living in nursing homes. Studies focusing on the epidemiology of colonization may help in the design of infection control strategies.

OBJECTIVE

To identify factors associated with MRSA colonization and the dissemination of clones among nursing home residents.

METHODS

Nasal swabs were collected from 300 persons from nine nursing homes in the city of Bauru, Brazil. Resistance to methicillin was identified through amplification of the mecA gene. Strain typing (Pulsed-Field Gel Electrophoresis) and characterization of the Staphylococcal Chromosome Cassette (SCC) mec was performed. Univariate and multivariable models were used to identify predictors of overall S. aureus and MRSA carriage.

RESULTS

Rates of S. aureus and MRSA colonization were 17.7 and 3.7%, respectively. Age and recent admission to a hospital were independently associated with colonization with S. aureus. MRSA colonization was associated with living in small (< 15 residents) and medium-sized (15-49 residents) facilities, as well as with recent hospitalization. Most MRSA strains carried SCCmec types II or IV, and there was evidence of clonal spread within and among different facilities.

CONCLUSIONS

MRSA may be introduced in nursing homes form hospitals or arise from the community setting. Screening for asymptomatic colonization may identify persons with greater risk for infection, and is advised for residents discharged from acute care hospitals.

Computed tomography-based volumetric tool for standardized measurement of the maxillary sinus

Volume measurements of maxillary sinus may be useful to identify diseases affecting paranasal sinuses. However, literature shows a lack of consensus in studies measuring the volume. This may be attributable to different computed tomography data acquisition techniques, segmentation methods, focuses of investigation, among other reasons. Furthermore, methods for volumetrically quantifying the maxillary sinus are commonly manual or semiautomated, which require substantial user expertise and are time-consuming. The purpose of the present study was to develop an automated tool for quantifying the total and air-free volume of the maxillary sinus based on computed tomography images. The quantification tool seeks to standardize maxillary sinus volume measurements, thus allowing better comparisons and determinations of factors that influence maxillary sinus size. The automated tool utilized image processing techniques (watershed, threshold, and morphological operators). The maxillary sinus volume was quantified in 30 patients. To evaluate the accuracy of the automated tool, the results were compared with manual segmentation that was performed by an experienced radiologist using a standard procedure. The mean percent differences between the automated and manual methods were 7.19% ± 5.83% and 6.93% ± 4.29% for total and air-free maxillary sinus volume, respectively. Linear regression and Bland-Altman statistics showed good agreement and low dispersion between both methods. The present automated tool for maxillary sinus volume assessment was rapid, reliable, robust, accurate, and reproducible and may be applied in clinical practice. The tool may be used to standardize measurements of maxillary volume. Such standardization is extremely important for allowing comparisons between studies, providing a better understanding of the role of the maxillary sinus, and determining the factors that influence maxillary sinus size under normal and pathological conditions.

Public policies on healthcare-associated infections: a Brazil and UK case study

To summarize the historical events and drivers underlying public policy for the prevention and control of healthcare-associated infections in Brazil and in the United Kingdom. In doing so, the article aims to identify lessons and recommendations for future development of public policy. The analysis is based on a historical overview of national healthcare-associated infections programs taken from previously published sources. Findings highlight how the development of healthcare-associated infections prevention and control policies followed similar trajectories in Brazil and the United Kingdom. This can be conceptualized around four sequential phases: Formation, Consolidation, Standardization, and Monitoring and Evaluation. However, while we identified similar phases of development in Brazil and the United Kingdom, it can be seen that the former entered each stage around 20 years after the latter.

Comparison of methods for the identification of microorganisms isolated from blood cultures

Background

Bloodstream infections are responsible for thousands of deaths each year. The rapid identification of the microorganisms causing these infections permits correct therapeutic management that will improve the prognosis of the patient. In an attempt to reduce the time spent on this step, microorganism identification devices have been developed, including the VITEK^® 2 system, which is currently used in routine clinical microbiology laboratories.

Methods

This study evaluated the accuracy of the VITEK^® 2 system in the identification of 400 microorganisms isolated from blood cultures and compared the results to those obtained with conventional phenotypic and genotypic methods. In parallel to the phenotypic identification methods, the DNA of these microorganisms was extracted directly from the blood culture bottles for genotypic identification by the polymerase chain reaction (PCR) and DNA sequencing.

Results

The automated VITEK^® 2 system correctly identified 94.7 % (379/400) of the isolates. The YST and GN cards resulted in 100 % correct identifications of yeasts (15/15) and Gram-negative bacilli (165/165), respectively. The GP card correctly identified 92.6 % (199/215) of Gram-positive cocci, while the ANC card was unable to correctly identify any Gram-positive bacilli (0/5).

Conclusions

The performance of the VITEK^® 2 system was considered acceptable and statistical analysis showed that the system is a suitable option for routine clinical microbiology laboratories to identify different microorganisms.

Toxigenic profile of methicillin-sensitive and resistant Staphylococcus aureus isolated from special groups

Background

Staphylococcus aureus is characterized by its pathogenicity and high prevalence, causing disease in both healthy and immunocompromised individuals due to its easy dissemination. This fact is aggravated by the widespread dissemination of S. aureus carrying toxigenic genes. The objective of this study was to determine the toxigenic profile of methicillin-sensitive S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA) in patients with purulent skin and/or soft tissue infections seen at the Dermatology Department of the University Hospital of the Botucatu Medical School, asymptomatic adults older than 60 years living in nursing homes, and prison inmates of the Avaré Detention Center.

Methods

PCR was used for the detection of the mecA gene, enterotoxin genes (sea, seb, and sec), exfoliative toxins A and B (eta and etb), toxic shock syndrome toxin 1 (tst), panton–valentine leukocidin (lukS-PV and lukF-PV), and alpha- and delta-hemolysins or cytotoxins (hla and hld).

Results

The results showed a significant prevalence of toxigenic genes among S. aureus isolates from asymptomatic individuals, with the observation of a higher prevalence of cytotoxin genes. However, the panton–valentine leukocidin gene was only detected in MSSA isolated from patients with skin infections and the tst gene was exclusively found in MSSA isolated from prison inmates.

Conclusions

The present study demonstrated a significant prevalence of toxigenic genes in MSSA and MRSA strains isolated from asymptomatic S. aureus carriers. There was a higher prevalence of cytotoxin genes.

Surgical site infection and its risk factors in colon surgeries

Abstract OBJECTIVE To identify the occurrence of surgical site infection (SSI) and its risk factors in patients undergoing colon surgery in a tertiary hospital located in the countryside of the state of São Paulo. METHOD Retrospective cohort study, with collection of information contained in the medical records of patients undergoing colon surgery in the period between January 2010 and December 2013. The studied variables were the possible risk factors related to the patient, to demographic characteristics and the surgical procedure. RESULTS In total, were evaluated 155 patients with an overall SSI incidence of 16.7%. A statistically significant association was found both in the univariate as in the multivariate analysis between the SSI and the following variables: male gender, Charlson index and mechanical bowel preparation. CONCLUSION The understanding of health professionals about the factors that influence the incidence of SSI in colon surgery may contribute to the quality of care provided to surgical patients, from effective actions to minimize the risk of infections.

Structure for prevention of health care-associated infections in Brazilian hospitals: A countrywide study

BACKGROUND

Minimal structure is required for effective prevention of health care-associated infection (HAI). The objective of this study was to evaluate the structure for prevention of HAI in a sample of Brazilian hospitals.

METHODS

This was a cross-sectional study from hospitals in 5 Brazilian regions (n = 153; total beds: 13,983) classified according to the number of beds; 11 university hospitals were used as reference for comparison. Trained nurses carried out the evaluation by using structured forms previously validated. The evaluation of conformity index (CI) included elements of structure of the Health Care-Associated Prevention and Control Committee (HAIPCC), hand hygiene, sterilization, and laboratory of microbiology.

RESULTS

The median CI for the HAIPCC varied from 0.55-0.94 among hospital categories. Hospitals with >200 beds had the worst ratio of beds to sinks (3.9; P < .001). Regarding alcoholic product for handrubbing, the worst ratio of beds to dispensers was found in hospitals with <50 beds (6.4) compared with reference hospitals (3.3; P < .001). The CI for sterilization services showed huge variation ranging from 0.0-1.00. Reference hospitals were more likely to have their own laboratory of microbiology than other hospitals.

CONCLUSION

This study highlights the need for public health strategies aiming to improve the structure for HAI prevention in Brazilian hospitals.

Healthcare-associated infections: challenges to public health in Brazil

This study presents a critical evaluation of the scientific literature related to this subject, aiming to assess the policies and administrative issues regarding the prevention and magnitude of healthcare-associated infections and discuss the challenges for their prevention in Brazil. The topics discussed included historical and administrative issues, challenges imposed by the characteristics of the healthcare system and the territorial dimension, laboratorial support limitations, costs, institutional culture, professional qualification, and patient engagement. It is urgent to hold a nationwide discussion among government representatives, institutions, and healthcare workers and users to overcome these challenges.