A post-COVID surge of Bordetella pertussis was observed globally. China has reported a high level of macrolide-resistant Bordetella pertussis (MRBP) in recent years; however, the epidemiology of MRBP in Hong Kong remains unknown. We retrieved archived B. pertussis isolates from respiratory samples collected at five regional public hospitals in Hong Kong between 2015 and 2024 and tested their minimum inhibitory concentration (MIC) for macrolides and other non-macrolide antibiotics using the Etest method. All isolates were also subjected to whole genome sequencing for genotypic resistance, Multi-locus Antigen Sequence Typing (MLST) and Multi-locus Variable Number of Tandem Repeat Analysis (MLVA) typing. Twenty-nine isolates of B. pertussis were included in the study. All isolates demonstrating phenotypic macrolide resistance harbored the A2047G mutation while showing low MIC to trimethoprim-sulfamethoxazole, doxycycline, levofloxacin, piperacillin-tazobactam and meropenem. In 2023 and 2024, 100% were MRBP and all belonged to the MT28 clone with the ptxP3 antigenic type. The MRBP isolates in Hong Kong were phylogenetically related to those from mainland China during the same period. There was no obvious correlation between macrolide resistance and clinical presentation, laboratory findings, management and outcome. Phylogenetic analysis suggests that MRBP isolates in Hong Kong and mainland China are closely related.

Background: Neonatal sepsis is a major cause of infant mortality, and it accounts for a significant consumption of antimicrobials in paediatrics. This is the first comprehensive study on neonatal sepsis in Hong Kong. Methods: From 2014 to 2023, all neonates admitted to a single institution with culture-proven infections from the blood and/or cerebrospinal fluid were selected and reviewed retrospectively. The infecting organisms, their antibiotic nonsusceptibility pattern, and the concordance of empirical antimicrobial therapy with the microbiological profiles were described and were further compared between infants of normal/low birth weight (≥1.5 kg) and very low/extremely low birth weight (<1.5 kg), early-onset sepsis (<72 h), and late-onset sepsis (4–28 days), the first and the second 5-year periods (2014–2018 vs. 2019–2023). Results: After contaminants were excluded, there were 118 affected neonates with 125 organisms identified. Fifty-nine were male. Thirty-four were very low/extremely low birth weight infants, and twenty-eight infants had early-onset sepsis. Patient demographics and the microbiology findings did not differ between the first 5 years and the latter 5 years. However, the incidence of neonatal sepsis was significantly lower in the latter 5 years (3.23 vs. 1.61 per 1000 live births, p < 0.001), the period that coincided with the COVID-19 pandemic. Escherichia coli was the most common Gram-negative pathogen. Streptococcus agalactiae and Streptococcus bovis group infections were more common in early-onset sepsis, while coagulase-negative Staphylococcus and non-E. coli Gram-negative pathogens were more likely to occur in late-onset sepsis. In very low/extremely low birth weight infants, the rate of cefotaxime or ceftriaxone nonsusceptibility among Gram-negative isolates was higher (p = 0.01), and concordance of empirical antimicrobial therapy was lower (p = 0.006). Conclusions: Management of neonatal sepsis remains challenging, and there is a need for optimising antimicrobial therapy, especially in preterm patients. Antepartum screening with intrapartum antibiotic prophylaxis is effective in reducing the risk of early-onset sepsis associated with S. agalactiae, while stringent infection control measures are important for the prevention of late-onset sepsis.

Scabies is a worldwide parasitic dermatosis with a significant health burden on the young and the elderly. Statistics about the prevalence of scabies in Hong Kong are not available. This is a retrospective study of patients from a regional hospital cluster in Hong Kong with microscopy-documented Sarcoptes scabiei infestations from January 2018 to December 2022. The condition was categorised into classical scabies and crusted scabies upon clinical presentation. Demographic data, comorbid diseases, mobility and residential status, seasonal variability, secondary bacterial infection, treatment and outcomes were described. These were compared between classic and crusted scabies. In total, 604 patients were identified, representing 51.65 per 100,000 discharged patients during the study period. The median age was 84 years and 54.5% were male. The majority (506 or 83.8%) came from residential care homes for the elderly. The mean time from admission to diagnosis was 8.8 days for community-acquired infestation. There were 564 and 40 cases of classic and crusted scabies, respectively. The two groups of patients were comparable in terms of residence in elderly homes, co-existing chronic illnesses, mobility, and time from admission to diagnosis. Forty-five (7.5%) patients had positive blood cultures temporally associated with scabies. Patients with crusted scabies were at higher risk for bacteraemia (7/40 versus 38/564, p = 0.022). Permethrin and benzyl benzoate were the most popular treatment regimens, with treatment failure observed in 59/397 (14.4%) and 18/173 (10.4%), respectively. There were 172 (28.5%) mortalities within 30 days of scabies diagnosis. Thus, the burden of scabies infestation is significant in Hong Kong. Hospitalised patients diagnosed with scabies are mainly senior citizens living in residential care homes for the elderly, suggesting reservoirs of S. scabiei in the community. Of concern, bacteraemic illnesses are common and significant mortality is temporarily associated with infestation. With a rising elderly population, there is a pressing need to understand and control scabies in Hong Kong. Our study did not find that common medical illness, besides immunosuppressive therapy, predisposed patients to crusted scabies. The crusted form of scabies was associated with a higher risk of bacteraemia. The current study provides a better perspective of the disease load of scabies in Hong Kong.

The emergence of carbapenem-resistant non-typhoidal Salmonella species (CR-NTS) has been observed in recent years, causing increasing challenges in the clinical management and control of Salmonella infections. However, CR-NTS had not been comprehensively studied in Hong Kong previously. We retrieved archived non-typhoidal Salmonella isolates demonstrating carbapenem resistance from five public hospitals in Hong Kong during January 2020–June 2025. The isolates were characterised by NG-TEST CARBA-5 and subjected to whole-genome sequencing (WGS) and phylogenetic analysis. Clinical information of CR-NTS cases was also reviewed. Fourteen CR-NTS isolates (0.3%, 14/4404) were identified during the study period. All 13 CR-NTS isolates (one isolate could not be recovered) were NDM (New Delhi metallo-β-lactamase)-positive, with the first case identified in March 2023. WGS revealed six Group B Salmonella monophasic variants of Salmonella enterica serovar Typhimurium ST34 harbouring the bla_NDM-5 gene. The most common plasmid replicon co-present among bla_NDM-5-positive isolates was IncHI2–IncHI2A (63.6%, 7/11). Among cases of CR-NTS in our study, self-limiting gastroenteritis was the most common presentation (84.6%, 11/13); none presented with invasive infections; travel history was present in 7.7% (1/13). Phylogenetic analysis showed the genotypic relatedness of the ST34 isolates identified in Hong Kong to those on the Chinese mainland, with the possibility of local CR-NTS acquisition via imported food sources. Our findings highlighted the importance of a One Health approach to the control of CR-NTS and the need for continuous antimicrobial resistance surveillance of Salmonella spp. in Hong Kong.