Prevalence of nasopharyngeal Streptococcus pneumoniae carriage and resistance to macrolides in the setting of azithromycin mass drug administration: analysis from a cluster-randomised controlled trial in Malawi, 2015–17

Antibiotic utilization patterns in Tanzania: a retrospective longitudinal study comparing pre- and intra-COVID-19 pandemic era using Tanzania Medicines and Medical Devices Authority data

Background

Antimicrobial resistance (AMR) is a growing public health concern globally, and misuse of antibiotics is a major contributor.

Objective

This study investigated antibiotic utilization patterns before and during the COVID-19 pandemic in Tanzania using data from the Tanzania Medicines and Medical Devices Authority (TMDA).

Methods

This retrospective longitudinal study analysed secondary data. The study compared antibiotics consumption in defined daily doses per 1000 inhabitants per day (DID) in two distinct eras: 2018-2019 as the pre-COVID-19 era and 2020-2021 as the intra-COVID-19 era. A sample t-test was conducted using Statistical Package for the Social Sciences.

Results

The study analysed 10 614 records and found an overall increase in antibiotics consumption from 2018 to 2021. We found that the consumption was 61.24 DID in the intra-COVID-19 era and 50.32 DID in the pre-COVID-19 era. Levofloxacin had the highest percentage increase in use, with a 700% increase in DID during the intra-COVID-19 era. Azithromycin had a 163.79% increase, while cefotaxime had a 600% increase. By contrast, some antibiotics exhibited a decrease in usage during the intra-COVID-19 era, such as nalidixic acid, which had a 100% decrease, and cefpodoxime, which had a 66.67% decrease.

Conclusions

Increased antibiotic consumption during the COVID-19 pandemic highlights the importance of implementing effective antimicrobial stewardship strategies to prevent AMR, especially during pandemics.

Effect of Biannual Azithromycin to Children under 5 Years on the Carriage of Respiratory Pathogens among Children Aged 7-11 Years

In the MORDOR I trial, children under 5 years of age were randomized to receive biannual (every 6 months) azithromycin for 2 years in Niger, Malawi, and Tanzania. In 30 Nigerien communities, children aged 7-11 years, who were not enrolled in the MORDOR I trial to receive biannual azithromycin, were assessed for carriage of seven respiratory pathogens. We aimed to see whether there were effects on the carriage of these seven respiratory pathogens among 3,187 children aged 7-11 years living in the 30 communities via nasopharyngeal swabs collected at baseline (N = 1,066), as well as at year 1 (N = 1,019) and year 2 (N = 1,102)-each about 6 months after azithromycin or placebo treatment of children under age five. Most children were positive for Haemophilus influenzae (baseline: 83.8%; interquartile range [IQR]: 78.7-90.4) and Streptococcus pneumoniae (baseline: 82.9%; IQR: 74.2-86.8) at all time points regardless of treatment group. There were no differences in prevalence nor quantity of H. influenzae (prevalence ratio: 0.95; 95% CI: 0.90, 1.02), S. pneumoniae (prevalence ratio: 1.01; 95% CI: 0.96, 1.07), or any of the other respiratory pathogens in the treatment versus control groups at any time point. S. pneumoniae serotype 6AB (7.7%) and Neisseria meningitidis serotype W135 (24.9%) were the most prevalent serotypes detected among all positive S. pneumoniae and N. meningitidis samples, respectively. Biannual azithromycin did not reduce carriage of respiratory pathogens 6 months after the most recent round of biannual azithromycin among older nontreated children (aged 7-11 years) living in treatment communities.

An Overview of Macrolide Resistance in Streptococci: Prevalence, Mobile Elements and Dynamics

Streptococcal infections are usually treated with beta-lactam antibiotics, but, in case of allergic patients or reduced antibiotic susceptibility, macrolides and fluoroquinolones are the main alternatives. This work focuses on studying macrolide resistance rates, genetic associated determinants and antibiotic consumption data in Spain, Europe and also on a global scale. Macrolide resistance (MR) determinants, such as ribosomal methylases (erm(B), erm(TR), erm(T)) or active antibiotic efflux pumps and ribosomal protectors (mef(A/E)-mrs(D)), are differently distributed worldwide and associated with different clonal lineages and mobile genetic elements. MR rates vary together depending on clonal dynamics and on antibiotic consumption applying selective pressure. Among Streptococcus, higher MR rates are found in the viridans group, Streptococcus pneumoniae and Streptococcus agalactiae, and lower MR rates are described in Streptococcus pyogenes. When considering different geographic areas, higher resistance rates are usually found in East-Asian countries and milder or lower in the US and Europe. Unfortunately, the availability of data varies also between countries; it is scarce in low- and middle- income countries from Africa and South America. Thus, surveillance studies of macrolide resistance rates and the resistance determinants involved should be promoted to complete global knowledge among macrolide resistance dynamics.