Advances in medicine are continuously emerging, challenging all members of the interprofessional team to remain aware of important updates and how they may improve clinical practice. This is particularly true for the prevention and treatment of infectious diseases. However, increasing demands on the time and resources of healthcare practitioners make it difficult to stay up-to-date on the latest clinical research and guidelines, as well as the implications for patient care. This article highlights recent advances in our understanding of infectious diseases and strategies to prevent and treat these illnesses.

GUT AND ORAL FLORA LINKED TO SUBCLINICAL CAD, INFLAMMATION

Coronary artery disease (CAD) is a prevalent heart condition in which atherosclerotic plaques form in the blood vessel. This results in reduced blood flow and consequently, oxygen flow, to the heart.^[1] It is estimated that more than 18 million adults living in the United States have CAD,^[2] which is a leading cause of morbidity and mortality.^[1]

TOPLINE; Multiple gut bacterial species that are commonly found in the mouth, especially several forms of Streptococcus, were associated with coronary atherosclerosis and systemic inflammatory biomarkers in a population-based observational study.^[3]

METHODOLOGY: Links between gut microbiota and coronary atherosclerosis have been studied primarily in symptomatic patients who were likely receiving therapies that may have shifted the balance of different organisms; there are fewer data from people with asymptomatic coronary disease.

Oral bacterial species are commonly transmitted to the gut, suggesting that gut and oral microbiota profiles are related and, further, that the gut may allow oral pathogenic bacteria to enter the circulation.

The current study included 8973 adults (53.7% women) without cardiovascular (CV) disease for whom adequate imaging and other data were available from the Swedish Cardiopulmonary Bioimage Study (SCAPIS) and the Malmö Offspring Study (MOS).

Researchers looked for associations between coronary artery calcium (CAC) scores (an index of atherosclerosis), gut bacterial species (identified in fecal samples), oral flora and pathologies, and systemic inflammatory biomarkers.

TAKEAWAY: Among the 64 species that correlated with CAC scores independently of CV risk factors, 51 showed a positive association, especially S anginosus and S oralis subsp oralis; patients with higher levels of those 2 species generally had more CV risk factors.

Twenty-five bacterial species that correlated with CAC scores were also associated with any coronary plaque by CT angiography. Five such species were associated with coronary stenosis > 50%, 39 with the modified Duke index, and 5 with carotid plaques (P < .05).

Of 54 species positively associated with CAC scores, 13 also tracked with C-reactive protein levels by high-sensitivity assay, 10 with leukocyte counts, and 11 with neutrophil counts (P < .05).

Bacterial species common in the oral cavity made up most of the species that correlated with all 3 inflammatory biomarkers; they included the streptococci most strongly correlating with CAC scores, that is, S anginosus, S oralis subsp oralis, and S parasanguinis.

IN PRACTICE: If the associations between gut bacterial species and markers of coronary atherosclerosis are found to be causal, such bacteria may "contribute to atherogenesis by direct infection or by altering host metabolism," the report states. "Future studies will show whether these species can be used as potential biomarkers or treatment targets."

SOURCE: The study was conducted by Sergi Sayols-Baixeras, PhD, Uppsala University, Sweden, and Instituto de Salud Carlos III, Madrid, Spain, and colleagues. It was published online July 12, 2023, in Circulation.^[3]

LIMITATIONS: Few participants had a high degree of subclinical atherosclerosis, which may reduce statistical power. Fecal samples disclose organisms primarily from the distal colon, but "microbial composition can vary extensively throughout the gastrointestinal tract." The investigators did not consider potential synergistic interactions among bacterial species that could influence their relationship to coronary atherosclerosis. Captured data regarding antibiotic therapy didn't account for any in-hospital treatment. The study's cross-sectional design precludes inferences about causation.

DIAGNOSIS OF VIRAL HEPATITIS IS STILL A MAJOR CHALLENGE

Viral hepatitis is inflammation of the liver that is caused by a virus. There are 5 common strains of viral hepatitis: A, B, C, D and E, each of which differ in terms of transmission and disease severity.^[4] According to the Brazilian Ministry of Health,^[5] between the years 2000 and 2021, more than 700,000 cases of viral hepatitis were diagnosed in Brazil. The Pan-American Health Organization (PAHO) warns that global mortality from viral hepatitis is likely to exceed the number of deaths due to HIV, tuberculosis, and malaria combined by 2040.^[6]

Every year on July 28, the World Health Organization marks World Hepatitis Day to increase awareness and understanding of viral hepatitis. In Brazil, the whole month of July is dedicated to viral hepatitis awareness. This campaign, named Julho Amarelo, or Yellow July, was established in Brazil by Law No. 13.802 in 2019. It seeks to reinforce surveillance, prevention, and control of these infections.

Paulo Abrão, MD, PhD, consultant for the Brazilian Society of Infectious Diseases and vice-president of the State of São Paulo Society of Infectious Diseases, warns that clinicians, regardless of specialization, must ask all adolescent and adult patients for rapid hepatitis B and C tests at least once in their lives.

In 2022, the PAHO issued a warning for the Americas. According to the organization, the region records 10,000 new hepatitis B infections and 23,000 deaths each year. For hepatitis C, estimates show that it is responsible for 67,000 new infections each year, and 84,000 deaths. 

Medscape's Portuguese edition spoke with Abrão about the topic. "I don't believe that the problem with viral hepatitis is getting worse. I think it has always been a big problem, and it has been around for a long time. We need to take action," he emphasized. For the doctor, the PAHO data likely reflect the increasing number of diagnoses in other South and Central American countries where the viral hepatitis scenario is worse than in Brazil.

"In Brazil, the number of new diagnoses is relatively stable. However, many people with these diseases are unaware that they have them. I think the greatest challenge is this: diagnosing the disease to be able to provide timely treatment," he said.

Hepatitis C Leads Diagnoses

Between 2000 and 2021, 280,000 hepatitis C cases were recorded in Brazil. The next most common were hepatitis B cases (264,640), followed by hepatitis A (168,175) and D (4259). According to the 2022 Epidemiological Viral Hepatitis Bulletin issued by the Brazilian Ministry of Health,^[7] the detection rate of confirmed hepatitis C cases across Brazil in 2021 was 5.2 per 100,000 people. The highest rate was found in Southern Brazil: 11.7 per 100,000 people. For hepatitis B, the detection rate across Brazil in 2021 was 3.4 per 100,000 people, the lowest observed in history. Southeastern Brazil had the highest incidence that year: 7.1 per 100,000 people.

The Brazilian Ministry of Health's press office informed Medscape that the 2022 viral hepatitis data will likely be released in the 2023 Epidemiological Hepatitis Bulletin, which is due to be issued in July. As of this writing, the bulletin was still in the final drafting phase.

Making Progress

The viral hepatitis scenario in Brazil is improving, said Abrão. In his view, this improvement is the result of the universal treatment program in effect for hepatitis C — all persons diagnosed with hepatitis C are treated, regardless of how much of the liver is compromised.

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