What are the current topics in infectious diseases?

Current Topics in Infectious Diseases

The most pressing current topics in infectious diseases are climate-driven expansion of vector-borne diseases (particularly threatening pregnant women), antimicrobial resistance accelerated by COVID-19, and revolutionary advances in tuberculosis treatment with shorter all-oral regimens.

Climate Change and Emerging Vector-Borne Diseases

Climate change represents the most urgent emerging infectious disease threat globally, facilitating unprecedented geographic expansion of mosquito-borne pathogens. 1, 2

• Rising temperatures and altered precipitation patterns are extending mosquito habitats to higher altitudes and latitudes previously unaffected by these diseases 1, 2
• Zika, West Nile, dengue, yellow fever, chikungunya, and malaria are increasingly impacting European populations and other regions that historically remained disease-free 1, 2
• Pregnant women face disproportionate risk from these emerging infections, with significant threats to both maternal and fetal health 1, 2
• Young children and elderly populations remain particularly vulnerable to severe disease outcomes 1, 2

Clinical Implications for Practice

• Maintain heightened awareness for travel history to regions with active vector-borne disease transmission 2
• Evaluate pregnancy status when considering patients with potential vector-borne infections 2
• Recognize that seasonal patterns of mosquito activity now extend beyond traditional timeframes 2
• Expect geographic presentations of traditionally tropical diseases in non-endemic areas 2

Antimicrobial Resistance Crisis Accelerated by COVID-19

The COVID-19 pandemic has significantly worsened antimicrobial resistance through inappropriate antibiotic prescribing, with particularly concerning increases in multidrug-resistant Gram-negative organisms. 3, 4, 5

Documented Resistance Increases

• Extended-spectrum β-lactamase (ESBL)-producing Klebsiella pneumoniae has shown rapid increases during the pandemic 3
• New Delhi metallo-β-lactamase (NDM)-producing carbapenem-resistant Enterobacterales have increased at multiple hospital sites 3, 4
• Carbapenem-resistant Acinetobacter baumannii incidence has risen compared to pre-pandemic levels 3, 4
• Pan-echinocandin-resistant Candida glabrata and multi-triazole-resistant Aspergillus fumigatus have emerged 3
• Meta-analysis shows a non-statistically significant increase in resistant Gram-negative organisms (incidence rate ratio 1.64,95% CI: 0.92-2.92) 5

Root Causes

• High rates of antimicrobial utilization in COVID-19 patients despite relatively low rates of actual bacterial co-infection or secondary infection 3
• Clinical uncertainty driven by lack of effective diagnostics and increased telemedicine practice led to inappropriate antimicrobial use 6
• Overuse of biocides and disinfectants during pandemic response 6
• Interruption of treatment for other conditions including tuberculosis 6

Protective Factors

• Enhanced infection prevention and control (IPC) measures introduced to minimize COVID-19 spread have reduced some healthcare-associated infections at specific sites 4
• Some studies report decreases in methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) attributed to heightened IPC practices 4
• Meta-analysis shows no significant change in MRSA or VRE incidence density (incidence rate ratio 0.99,95% CI: 0.67-1.47) 5

Critical Stewardship Priorities

Appropriate antimicrobial prescription according to stewardship principles, quality diagnostics, and aggressive infection control measures are essential to prevent further MDRO emergence. 3

• Minimize empiric broad-spectrum antibiotic use in COVID-19 patients 4
• Absence of reported enhanced IPC and antimicrobial stewardship programs was associated with increased Gram-negative AMR (risk ratio 1.11,95% CI: 1.03-1.20) 5
• Maintain COVID-19-related IPC protocols beyond the pandemic to reduce overall HAI burden 4

Revolutionary Advances in Tuberculosis Treatment

Tuberculosis treatment has undergone dramatic transformation with shorter all-oral regimens that have markedly improved treatment completion rates and reduced morbidity. 1, 7

Drug-Susceptible TB Advances

• Multiple trials (Study 31/A5349, TRUNCATE-TB, SHINE) show promising results for shortening treatment duration below the traditional 6 months 1
• Dose optimization of rifamycins and repurposed drugs offers hope for safer, more effective regimens 1
• WHO clinical guidelines have been updated multiple times in recent years to incorporate these advances 1

Drug-Resistant TB Breakthroughs

The BPaLM regimen (bedaquiline + pretomanid + linezolid + moxifloxacin) for 26 weeks represents the preferred first-line oral therapy for fluoroquinolone-susceptible MDR/RR-TB. 7

• STREAM, NiX-TB, ZeNix, and TB-PRACTECAL trials demonstrated efficacy of shorter regimens for drug-resistant TB 1
• BPaLM is indicated for adults ≥14 years with MDR/RR-TB who are fluoroquinolone-susceptible, have no prior >30-day exposure to component drugs, and are not pregnant or breastfeeding 7
• If fluoroquinolone resistance is identified after treatment initiation, switch immediately to BPaL (without moxifloxacin) and extend total treatment to 9 months 7

Critical Monitoring Requirements

• Baseline ECG and repeat ECGs at weeks 2,12, and 24 are required; discontinue bedaquiline if QTcF >500 ms 7
• Monthly complete blood counts to detect linezolid-induced myelosuppression 7
• Monthly liver function tests (AST, ALT, bilirubin, alkaline phosphatase) 7
• Regular neurologic assessment for peripheral and optic neuropathy 7
• Therapeutic drug monitoring of linezolid, when available, significantly improves safety outcomes 7

Ongoing Challenges

• Despite advances, tuberculosis remains a leading infectious cause of death with 1.6 million deaths in 2021 1
• MDR/RR-TB incidence is increasing, with an estimated 450,000 new cases in 2021 1
• Only about one-third of drug-resistant TB cases are detected and treated annually 1
• Two-thirds of individuals who develop MDR/RR-TB each year do not receive appropriate treatment 1

Social Determinants Underlying Infectious Disease Control

Both tuberculosis and COVID-19 demonstrate that infectious disease control requires addressing social determinants beyond biomedical interventions. 1

• Poverty, population density, urban/rural setting, and population growth pose considerable challenges for preventing and controlling infectious diseases 1
• Universal health coverage and health-related social protection must prioritize vulnerable populations 1
• Exclusively biomedical responses have proven insufficient to eliminate TB despite curing millions of people 1
• Rapid and effective measures against poverty and major sources of inequality are urgently needed to develop better health in the post-COVID-19 world 1

Emerging Diagnostic Technologies

Newer rapid diagnostic methods including GeneXpert, whole genome sequencing, and Myc-TB offer solutions for rapid detection of drug resistance. 1

• In 2020,71% of people diagnosed with bacteriologically confirmed pulmonary TB were tested for rifampicin resistance, an increase from 2018 and 2019 1
• Rapid diagnostics are essential given that only 157,903 of 500,000 estimated new RR-TB cases were notified in 2020 1

Common Pitfalls to Avoid

• Do not prescribe empiric antibiotics for COVID-19 patients without clear evidence of bacterial co-infection or secondary infection 3, 4
• Do not delay initiation of BPaLM while awaiting fluoroquinolone susceptibility results; start empirically and switch to BPaL if resistance is confirmed 7
• Do not use BPaLM for central nervous system, osteoarticular, or disseminated (miliary) TB; employ individualized 18-20 month regimens instead 7
• Do not overlook travel history and pregnancy status when evaluating patients for potential vector-borne infections 2
• Do not assume traditional geographic and seasonal patterns for vector-borne diseases; climate change has altered these fundamentally 1, 2