Rapid Spread of New “Super-Strain” Bacteria Threatens Asia

Medical News: A newly identified “super-strain” of antibiotic-resistant bacteria is causing serious health concerns as it spreads through hospital systems in Asia. Named ST164, this variant of Carbapenem-resistant Acinetobacter baumannii (CRAB) has evolved to resist most antibiotics, creating a global health challenge due to the lack of effective treatments. Researchers from the University of Birmingham in the United Kingdom and Zhejiang University in China, have uncovered critical findings about the strain’s rapid transmission in hospitals, particularly in intensive care units (ICUs), and have underscored the urgent need for robust infection prevention strategies to limit its spread.


Rapid Spread of New “Super-Strain” Bacteria Threatens Asia

Rising Threat of ST164 in Hospitals
In a study conducted in 2021, researchers conducted a deep dive into the presence of CRAB in an ICU in Hangzhou, China, with a specific focus on how the new ST164 strain emerged and spread. This Medical News report brings to light the alarming findings: CRAB accounted for over 80% of Acinetobacter baumannii samples in the ICU, with the ST164 strain representing 40.2% of these samples. This strain showed even greater resistance to carbapenems - an antibiotic often considered the last line of defense - compared to other variants. The ST164 strain’s remarkable ability to withstand multiple classes of antibiotics is raising major concerns.
 
Researchers conducted whole-genome sequencing on the CRAB strains found in the ICU, revealing that ST164 has been evolving since mid-2020. In addition, the proportion of another CRAB strain, GC2, which was once dominant, dropped from 99.5% in 2019 to just over half (50.8%) by 2021. Meanwhile, ST164 has continued to gain ground, establishing itself as a significant threat within the ICU setting.
 
Tracking the Spread of a Super-Bug
The research team traced the origins of the CRAB strains within the ICU and found that other hospital wards and incoming patients were frequently introducing new sources of infection into the ICU. This not only underscores the contagiousness of CRAB bacteria but also highlights how easily these super-bugs spread through shared medical equipment, airflow systems, and even healthcare workers.
 
Alarmingly, CRAB can survive for extended periods on surfaces and equipment, leading to possible outbreaks in hospital environments.
 
This issue of high resistance and rapid transmission makes it increasingly difficult to control the spread of CRAB infections in hospital settings, as regular infection prevention and control (IPC) measures have proven insufficient. According to Professor Alan McNally from the University of Birmingham, ST164 is becoming more prominent in ICU settings and has the potential to spread widely across Asia and beyond. The bacteria’s ability to resist antibiotics raises the stakes, making effective monitoring crucial to prevent widespread outbreaks.
 
The Challenge of High Antibiotic Resistance&l t;br /> CRAB bacteria like ST164 can cause severe infections, including pneumonia, bloodstream infections, meningitis, urinary tract infections, and skin infections. Treatment for these infections is often complex and limited, with CRAB strains showing resistance even to carbapenems, a class of antibiotics usually reserved for the most dangerous bacteria. Notably, ST164 exhibited double the resistance level to carbapenems compared to the GC2 strain, making it more challenging to treat.
 
The study, supported by funding from the Medical Research Council and the National Natural Science Foundation of China, found that the ST164 strain carries specific genes (blaNDM-1 and blaOXA-23) that contribute to its antibiotic resistance. These genes provide the bacteria with an enhanced ability to survive in the presence of carbapenems, thereby rendering traditional treatment approaches largely ineffective.
 
Global Public Health Risks and the Need for New Treatments
The World Health Organization has classified CRAB as a priority pathogen for which new treatments are urgently needed due to its resistance to many antibiotics and its ability to spread globally. As antibiotic-resistant infections continue to rise, the need for effective IPC strategies in hospitals has never been more pressing. In ICUs, where patients are critically ill, infections from antibiotic-resistant bacteria like CRAB pose severe risks and lead to higher rates of mortality.
 
Professor Willem van Schaik, another co-author of the study from the University of Birmingham, emphasized the global threat posed by CRAB, particularly the ST164 clone. He pointed out that the bacteria’s high resistance levels not only affect patient outcomes but also place a burden on healthcare systems worldwide. In the absence of new antibiotics, hospitals must rely on rigorous infection prevention measures to curb the spread of these infections.
 
Why Infection Control Measures Matter
The study’s findings demonstrate the importance of robust IPC protocols. After an initial study of CRAB in the Hangzhou ICU in 2019, the research team implemented a series of IPC measures targeting the ICU environment, staff, and patients. However, the onset of the COVID-19 pandemic delayed further implementation of these measures until late 2020. During the pandemic, increased antibiotic usage likely contributed to higher resistance levels among bacteria in hospitals, complicating the fight against CRAB.
 
Although the IPC measures led to a reduction in the number of CRAB-positive samples, the ST164 strain still managed to establish itself within the ICU. To effectively contain CRAB, hospitals may need even stricter protocols, such as isolating CRAB-positive patients before admitting them to ICUs. Additionally, the study found that frequent introductions of new CRAB strains from other wards and facilities present an ongoing challenge.
 
Why Genomic Surveillance is Essential
This study highlights the value of genomic surveillance in identifying and tracking antibiotic-resistant strains in hospital settings. By analyzing the genetic composition of CRAB strains, researchers were able to monitor how these bacteria adapt and spread. Such insights enable hospitals to make informed decisions about IPC strategies and to better understand the evolution of antibiotic-resistant bacteria.
 
In their research, the team found that ST164 has been detected in at least 26 countries across five continents, indicating that it is a growing global concern. With the ability to accumulate resistance genes independently, ST164 poses a high risk for cross-border transmission, making international surveillance and cooperation essential.
 
Conclusions and Future Directions
The emergence of the ST164 strain of CRAB in Asia signals a new era in the fight against antibiotic-resistant infections. This study underlines the need for a multifaceted approach to infection prevention and control, one that combines robust hygiene practices, patient screening, and targeted use of antibiotics to reduce resistance pressure. Hospitals must stay vigilant by employing high-resolution genomic tracking and constantly adapting IPC strategies to keep up with the evolving threats posed by bacteria like ST164.
 
Without new antibiotics, the onus falls on healthcare providers to prevent the spread of CRAB infections within ICUs. Continued research into the persistence and transmission of CRAB will also be crucial to designing more effective infection control policies in hospitals. Furthermore, as ST164 continues to emerge as a significant pathogen, targeted IPC strategies focusing on ICU environments, patients, and healthcare staff will be essential to mitigate its impact.
 
The study findings were published in the peer-reviewed journal: Nature Communications.
https://www.nature.com/articles/s41467-024-53817-x
 
For the latest on new strains of antibiotic-resistant bacteria, keep on logging to Thailand Medical News.
 
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