The surveillance programme was deliberately time-limited, running from January to April 2024, and was designed to capture both the severe end of the disease spectrum and the milder cases circulating in the wider population. Paediatric samples that tested positive for M. pneumoniae were collected from participating hospitals as well as from Singapore’s community acute respiratory infection surveillance programme. All of these specimens were funnelled to the National Public Health Laboratory, where they underwent genotypic testing for macrolide resistance. This dual sampling strategy matters scientifically: hospital-based studies alone tend to overestimate the clinical severity of resistant infections, because resistant cases that fail first-line therapy are more likely to end up in hospital in the first place. By including community cases, the Singapore team could compare resistant and susceptible strains across the full range of illness, from children treated as outpatients to those requiring admission.

In total, 412 M. pneumoniae cases were successfully genotyped and included in the analysis, comprising 275 hospitalised children and 137 community cases, all aged between zero and sixteen years. Among the hospitalised group, 16.7 percent carried the resistance mutation, with a 95 percent confidence interval of 12.5 to 21.7 percent. In the community, the figure was slightly higher at 19.7 percent, with a confidence interval of 13.4 to 27.4 percent. The mutation in question, A2063G, is a single nucleotide substitution in the 23S ribosomal RNA gene. This is the molecular heart of the macrolide mechanism: macrolides work by binding to the 23S rRNA component of the bacterial ribosome’s 50S subunit, physically blocking the exit tunnel through which the growing protein chain must pass. A single base change at position 2063 alters the conformation of the binding pocket, dramatically reducing drug affinity and rendering the antibiotic largely ineffective, while leaving the bacterium otherwise intact and transmissible.

The genetic basis of this resistance explains both its rapid spread and its persistence. Because resistance arises from a point mutation rather than the acquisition of a foreign resistance gene, it can emerge and fix within circulating lineages under antibiotic pressure, and it is passed vertically to daughter cells during replication. Unlike some resistance mechanisms that carry fitness costs, MRMP strains have demonstrated in multiple Asian settings that they can sustain themselves in the population over years. Countries such as China, Japan, and South Korea have reported resistance rates exceeding 80 to 90 percent in some paediatric cohorts, which makes Singapore’s figure of roughly 17 to 20 percent comparatively moderate. The study’s authors suggest that this intermediate level may reflect Singapore’s position at an earlier stage of the same epidemiological trajectory, underscoring the value of periodic surveillance to detect any upward shift before it becomes entrenched.

Perhaps the most clinically consequential finding concerns what resistance actually does to children who are infected. In adjusted statistical analyses, children with MRMP had a higher likelihood of recent overseas travel, with an odds ratio of 2.28 and a confidence interval of 1.09 to 4.77, hinting at imported strains or travel-linked transmission. More tangibly, resistant infections were associated with a longer duration of fever, averaging an additional 2.24 days compared with macrolide-susceptible cases, a difference that was statistically significant at p less than 0.01. Hospitalisation was also prolonged, by an average of 0.94 days, with a p value of 0.01. These differences are biologically coherent: if the first-line antibiotic cannot inhibit the bacterium, the child’s immune system must do the work alone, prolonging symptomatic illness and extending the time needed for recovery, while clinicians may cycle through additional treatments or investigations before the infection is brought under control.

Crucially, however, the study found no evidence that resistance translated into greater disease severity beyond these temporal measures. The researchers detected no differences between hospitalised MRMP and macrolide-susceptible cases in age, ethnicity, comorbidities, symptomatology, the presence of co-infections, care acuity, or mortality. All MRMP inpatients were discharged well. This pattern is consistent with the prevailing understanding of M. pneumoniae pathogenesis, in which much of the lung damage is driven by the host’s inflammatory response rather than by direct bacterial destruction of tissue. A resistant strain may persist longer and provoke a more prolonged inflammatory course, but it does not appear to be intrinsically more virulent. For clinicians and parents alike, the practical message is that resistant infections tend to be longer and more inconvenient rather than more dangerous, at least at the current prevalence.

The demographic and clinical equivalence between resistant and susceptible cases also carries an important diagnostic implication. Because children with MRMP cannot be distinguished from those with susceptible infections on the basis of symptoms, age, or risk factors, clinicians cannot identify resistance at the bedside. In settings where resistance rates are high, this has driven interest in rapid molecular resistance testing, which can detect the 23S rRNA mutations directly from respiratory specimens within hours. The Singapore findings, showing that resistance is present at a meaningful but not overwhelming frequency, suggest that universal resistance testing is not yet an urgent necessity locally, but the study provides exactly the kind of baseline prevalence data that health authorities need to decide when such testing would become cost-effective. The authors note that the findings do not indicate an immediate need to alter current local empirical treatment recommendations, although they caution that further research is needed to evaluate treatment effectiveness in MRMP infections specifically.

The association with recent overseas travel adds a layer of epidemiological interest. With an odds ratio above two, travel history emerged as the only demographic or epidemiological factor independently linked to resistant infection in the adjusted analysis. This fits with the broader geography of macrolide resistance, which is far more established in many neighbouring Asian countries than in Singapore itself. Cross-border movement of both people and microbial lineages is a well-documented driver of antimicrobial resistance dissemination, and the finding suggests that imported strains may be seeding local circulation. It also illustrates why resistance surveillance is inherently a regional, and indeed global, undertaking: a country’s resistance profile is shaped not only by its own antibiotic prescribing practices but also by those of its neighbours and by the volume of travel connecting them.

The study was conducted under Singapore’s national infectious disease surveillance framework, operating under the provisions of the Infectious Diseases Act, which meant that statutory public health surveillance provisions governed the work and institutional review board approval was not required. The research received no specific external funding, and the analytical work drew on the bacteriology team at the National Public Health Laboratory for sample processing and downstream analysis of the respiratory specimens. The breadth of institutional involvement, spanning the Communicable Diseases Agency, the National Centre for Infectious Diseases, the Saw Swee Hock School of Public Health, National University Hospital, and KK Women’s and Children’s Hospital, reflects the multicentre design that gives the prevalence estimates their robustness across both hospital and community settings.

The authors conclude that periodic surveillance and responsible antimicrobial stewardship are crucial to mitigating rising resistance, and their data support a measured rather than alarmist response. Macrolides remain an appropriate first-line empirical choice for paediatric M. pneumoniae infections in Singapore for now, since the large majority of circulating strains remain susceptible and no severity penalty from resistance has been demonstrated. But the study also documents that resistance has firmly arrived, that it prolongs fever and hospital stays, and that it is associated with travel-linked introduction. As M. pneumoniae continues its cyclical epidemics around the world, and as neighbouring countries grapple with far higher resistance levels, the Singapore experience offers a template for how a well-organised surveillance system can track a resistance problem early, quantify its clinical impact honestly, and buy time for stewardship measures to work before the therapeutic calculus fundamentally changes.

Subject of Research: Macrolide-resistant Mycoplasma pneumoniae epidemiology and clinical impact in Singaporean children

Article Title: Epidemiology and clinical impact of macrolide-resistant Mycoplasma pneumoniae in Singapore – findings from a multicentre surveillance programme

Article References: Keng, B., Lee, J. G. J., Mah, T. K. L., Cheng, S., Ho, C., Goh, A., Khamis, N. H., Khong, W. X., Chae, S.-R., Cui, L., Cho, S. S. L., Lin, R. T. P., Tee, N., Thoon, K. C., Yung, C. F., Li, J., Maiwald, M., Loo, L. H., Yelen, … Said, Z. (2026). Epidemiology and clinical impact of macrolide-resistant Mycoplasma pneumoniae in Singapore – findings from a multicentre surveillance programme. BMC Infectious Diseases. https://doi.org/10.1186/s12879-026-14346-8

Image Credits: AI Generated

DOI: 10.1186/s12879-026-14346-8

Keywords: Mycoplasma pneumoniae, macrolide resistance, antimicrobial resistance, surveillance, paediatrics, community-acquired pneumonia, A2063G mutation, Singapore, epidemiology, public health, antibiotic stewardship, BMC Infectious Diseases