Study sheds light on global laboratory-acquired infections and pathogen escapes

By Vijay Kumar MalesuReviewed by Benedette Cuffari, M.Sc.Dec 17 2023

In a recent study published in The Lancet Microbe, researchers analyze the global incidences of laboratory-acquired infections (LAIs) and accidental pathogen escapes from 2000 to 2021 to identify patterns, risks, and the need for improved reporting and management strategies.

Study: Laboratory-acquired infections and pathogen escapes worldwide between 2000 and 2021: a scoping review. Image Credit: Sirichai Saengcharnchai / Shutterstock.com

Background 

LAIs are infections contracted from exposure to biological agents in laboratory settings, whereas accidental pathogen escapes from laboratory settings (APELS) occur due to breaches in biocontainment. Both of these events are important for clinical, research, academic, and pharmaceutical manufacturing laboratory work.

In the early 20^th century, LAI investigations were initially performed to identify their causes and avoid subsequent similar incidents. Recent recommendations emphasize risk-based and evidence-based strategies to reduce LAI and APELS incidents by adhering to high biosafety and biosecurity standards.

Nevertheless, further research is needed to better understand the dynamics, causes, and consequences of LAIs and APELS to guide the development of more effective biosafety protocols and global reporting systems.

About the study 

The researchers searched literature published between January 2000 and September 2021 on PubMed using specific terms related to LAIs and APELS. In addition to peer-reviewed articles, online reports were sourced from databases such as the American Biological Safety Association International Laboratory-Acquired Infection Database, ProMED, and the Belgian Biosafety Server. These articles and reports were carefully scrutinized, including reference materials mentioned therein, primarily in Chinese, English, and German.

Data extraction was carefully performed by two authors who independently searched and verified the information for accuracy, with a third author validating the data. This information was then methodically compiled into summary tables that categorized the incidents into LAIs and APELS. Extensive details for each incident were recorded, including the type of pathogen, number of cases and fatalities, cause, and geographic location.

The scope of the study was specifically tailored to include LAIs among laboratory personnel, staff, and students and extended to LAIs in hospital or research lab environments associated with university and college training activities. APELS cases were also included if they led to infections in laboratory personnel and the wider community. The team excluded reports lacking sufficient detail, those not pertaining directly to LAIs or APELS, or instances of pathogen exposure without infection.

LAIs and APELS were categorized based on activity similarities, with “unknown” classifications for inconclusive results and “not stated” for cases without explicit causative agent identification. APELS incidents were further divided into “internal” and “external” categories based on the containment breach's cause, location, and extent.

Using Stata/BE 18.0 for Mac, the researchers ranked causal pathogens, pathogen risk groups, case numbers, and geographical locations. Summary data were visualized using Microsoft Power BI and R software, which provided important insights into the trends and patterns of LAIs and APELS over the two-decade period.

Study findings 

In the present comprehensive study, 164 reports were initially identified, 94 of which discussed 309 LAIs that met the criteria for inclusion. Over 90% of these reports were derived from peer-reviewed journals, whereas 9.6% were online articles. Geographically, most reports originated from Europe, North America, and Asia, particularly the United States of America, which accounted for a significant proportion of the individual LAI cases.

Regarding the pathogens responsible for LAIs, 309 cases were attributed to 51 pathogens. Salmonella enterica Typhimurium (S Typhimurium) was the most prevalent, followed by Salmonella enteritidis, vaccinia virus, Brucella spp, and Brucella melitensis. Pathogens were classified into various risk groups (RGs), with RG2 pathogens being the most common.

The primary cause of these infections was identified as procedural errors, which contributed to a significant percentage of cases, followed by unknown causes and needlestick injuries. Procedural errors were the most common cause of fatal outcomes in LAIs.

In the U.S., S. Typhimurium, S. enteritidis, and Cryptosporidium spp were predominant, whereas China reported cases mainly caused by Brucella spp and the severe acute respiratory syndrome coronavirus (SARS-CoV). A detailed risk assessment for different pathogen groups provided insights into the prevalence and impact of various bacterial, viral, parasitic, and fungal pathogens, as well as prions.

The study further detailed 16 incidents of APELS involving bacterial and viral pathogens. Although generally not causing infections, these incidents posed potential exposure risks to staff, the surrounding community, or animals. Notably, some APELS were linked to significant disease outbreaks, such as brucellosis infections in China.

APELS incidents primarily involved RG3 pathogens and were often external breaches, most of which occurred in research or university laboratories, with a notable number reported in vaccine production facilities. Geographically, these incidents were most frequently reported in the U.S., followed by the United Kingdom, China, and other countries.