Abstract
Antimicrobial resistance (AMR) represents an escalating global health crisis, posing severe threats to public health by undermining medical advancement, increasing mortality rates, prolonging hospitalisations, and imposing significant economic burdens. The WHO has identified carbapenem-resistant Acinetobacter baumannii (CRAb), Pseudomonas aeruginosa (CRPa), and Enterobacterales (including Escherichia coli (CREc) and Klebsiella pneumoniae (CRKp)), along with extended-spectrum β-lactamase (ESBL)-producing Enterobacterales, as critical pathogens. In 2019, bacterial AMR contributed to 1.27 million direct deaths globally and played a role in nearly 5 million fatalities, underscoring the urgent need for effective interventions, particularly in low resource setting countries with fragile healthcare infrastructures. Despite this critical need, Fiji, an upper-middle-income country and central hub in the South Pacific, lacks comprehensive data on AMR prevalence and characteristics within its healthcare system. Fiji's healthcare predominantly relies on public hospitals, including the Colonial War Memorial Hospital (CWMH), Lautoka Hospital (LTKH), and Labasa Hospital (LBSH), which are crucial in addressing the medical needs of its population.
To address this knowledge gap, a six-year retrospective review of laboratory data from Fiji’s hospitals revealed increasing resistance among A. baumannii, P. aeruginosa, and Enterobacterales, with alarming rates of multidrug resistance in A. baumannii and significant resistance to ceftriaxone and ESBL production in Enterobacterales. Further investigation into CRAb at CWMH in 2019 identified two clonal nosocomial outbreaks of CRAb sequence type 2 (ST2) associated with high mortality rates. Clone 1 strains were phylogenetically linked to strains involved in previous outbreaks affecting Fijian newborns in 2016/2017, and were also phylogenetically linked to strains from Samoa, Samoans in New Zealand, and Australia, suggesting the presence of an Oceania CRAb ST2 outbreak strain. Moreover, local adaptation of these ST2 clone 1 strains in Fiji and Samoa was observed, highlighting genetic changes in response to the healthcare environments of Fiji and Samoa. CRAb ST2 clone 2 strains were phylogenetically linked to strains from India, suggesting transnational movement between Fiji and India.
Subsequently, a prospective study across all three hospitals detected multiple clonal outbreaks of CRAb ST2, CRPa ST773, CREc ST410, and CRKp ST16, with transmission within and between major hospitals and peripheral healthcare facilities over an extended period. Along with ongoing circulation of the two CRAb ST2 clonal strains identified in the retrospective study,a third clone of CRAb ST2 was identified. Carbapenem resistance in these different bacterial species and strains was attributed to various mechanisms, including carbapenemase genes (blaOXA-23, blaNDM-1, blaNDM-5, blaNDM-7); these genes were encoded by plasmids and other mobile genetic elements (MGEs), promoting rapid dissemination within healthcare settings and the broader community. These clonal nosocomial outbreaks were associated with high mortality rates, underscoring an escalating public health threat in Fiji, exacerbated by the common inappropriate use of meropenem.
Further investigations into the hospital environment as a potential source of these outbreaks identified multiple CRAb clones (ST2, ST25, ST499) resistant to multiple antimicrobial classes in CWMH. These clones were found on high-touch surfaces and were phylogenetically linked to clinical CRAb isolates from previous nosocomial outbreaks in Fiji since 2019. This underscores a potential association between environmental contamination and subsequent infections, raising concerns about the effectiveness of current infection prevention and control measures in Fiji.
Overall, the endemic presence of CRAb ST2, CRPa ST773, and CREc ST410and CRKp ST16 in Fiji continues to pose a significant and ongoing threat to public health. This persistent threat is compounded by the finding of multiple clonal outbreaks across major hospitals and peripheral healthcare facilities, associated with alarmingly high mortality rates. This study highlights ongoing challenges in infection prevention and control measures, with environmental contamination identified as a potential source of infection. Given these challenges, urgent action is required, including robust national and international AMR surveillance, enhanced antimicrobial stewardship, and exploration of alternative treatment strategies. Strengthening infection prevention and control practices and implementing comprehensive surveillance are imperative to effectively mitigate the spread of these resistant pathogens in Fiji and globally.