# Biosafety for Culturing Environmental Samples The one-sentence difference: a clinical specimen arrives with a suspected agent and patient history, while an environmental sample carries an undefined mix of bacteria, fungi, and viruses at unknown concentrations, so containment must be chosen for the worst plausible hazard rather than the most likely one. Rule of thumb: culture routine soil, water, and surface samples at [Biosafety Level](/knowledge/diagnostics/emerging-tech/biosafety-levels-1-4-a-comparative-framework-for-diagnostic-laboratory-design) 2 (BSL-2), move to BSL-3 practices or full BSL-3 containment whenever a high-consequence agent such as *Bacillus anthracis* or highly pathogenic [avian influenza](/knowledge/bacteria/avian-bacteria/avian-influenza-new-zealand-kerala-outbreaks-jessamine-county-updates) (HPAI) virus is plausible, and prefer validated inactivation with molecular testing when you need an answer but not a live isolate. The best biosafety setup for environmental samples culturing is the one matched to a written biosafety risk assessment, not the one the neighboring lab happens to use. This guide covers that assessment, the main containment and testing options, the pros and cons of each, and the bench habits that keep the work safe. ## Why Environmental Samples Are Different Environmental matrices concentrate hazards in ways clinical samples rarely do. Soil can hold *B. anthracis* spores that persist in the environment and sustain anthrax transmission in endemic regions [1]. Water systems amplify *Legionella*, the bacterium that causes Legionnaires' disease, a severe pneumonia, and culture remains the gold standard for enumerating environmental *Legionella* even though long incubation and modest sensitivity can delay outbreak response [2]. Arthropod samples raise the stakes further. A metagenomic survey of *Rhipicephalus microplus* ticks from border regions of Yunnan, China identified 63 viral families, including 28 with known animal hosts such as Flaviviridae, Phenuiviridae, and Peribunyaviridae, together with 167 bacterial genera dominated by pathogenic groups including *Coxiella* [3]. A sample that looks like plain dirt or a plain tick can carry agents nobody planned for. The matrix itself creates exposure routes. Dry soil generates dust that stays airborne long after handling. Water samples vortexed in open tubes aerosolize their contents. Biofilms shield organisms from disinfectants and from heat. The four routes you must control are inhalation of aerosols and dust, splashes to eyes and mouth, percutaneous inoculation from sharps, and hand-to-face ingestion. Every control in this article maps back to those four routes. ## Start With a Written Biosafety Risk Assessment A biosafety risk assessment is a documented evaluation of what in a task could harm people, how exposure could happen, and which controls bring the remaining risk to an acceptable level. The assessment is the first bench step for any new sample type, and the document you revisit after every incident, every new agent in your region, and every procedural change. Work through six steps: 1. **Identify the agent hazards.** List what is known, what is suspected, and what is unknown. Pasture soil during a livestock mortality investigation carries different hazards than the same soil collected for a teaching exercise. 2. **Characterize the matrix.** Ask whether the sample generates dust, whether it is wet or dry, whether it contains sharps such as glass, metal, or bone fragments, and how much organic load will challenge your disinfectants. 3. **Walk through each procedure.** Vortexing, grinding, sieving, sonication, centrifugation, pipetting, streaking, and plate reading each create aerosols or contact opportunities. Flag the steps that release the most energy. 4. **Consider the people.** Training level, immunocompromise, pregnancy, and prior exposure history all change the acceptable risk level for a given task. 5. **Select controls in order of strength.** Elimination or substitution comes first (inactivate the sample, run a molecular test, or refer it out). Engineering controls come next (Class II biosafety cabinet, sealed centrifuge rotors). Administrative controls follow (standard operating procedures, access limits, training). Personal protective equipment (PPE) is the last layer, not the first. 6. **Document, communicate, and revisit.** Post the summary where the work happens, brief everyone who touches the sample, and review the assessment on a defined schedule. A short example shows the logic. Suppose a clinic receives a swab from a livestock wound on a farm that also reported sudden animal deaths. The assessment flags *B. anthracis* as plausible, identifies the direct smear and any dry packing material as aerosol risks, and selects controls: open the swab only in a Class II cabinet, prepare smears with minimal agitation, defer culture to a reference facility, and communicate the suspicion before anything ships. The same swab from a farm with no unusual deaths would support a standard BSL-2 [bacterial culture](/blog/guides/bacterial-culture) instead. ## Containment Options for Culturing Environmental Samples Five practical approaches cover nearly every environmental culturing situation. The table compares them side by side, and the sections that follow explain each option on its own terms. | Approach | Best suited for | Core controls | Pros | Cons | |--|--|--|--|--| | Standard BSL-2 culture | Routine water, soil, and surface samples with no suspicion of high-consequence agents | Class II biosafety cabinet (BSC) for all open manipulation, gloves and fluid-resistant gown, restricted access, autoclave waste stream | Work stays on site, organisms stay viable for full identification, lowest cost and fastest setup | Inadequate if a high-consequence agent is present, culture turnaround runs days to weeks | | Enhanced BSL-2 (BSL-2 with BSL-3 practices) | Dusty soils, farm-linked samples, unknowns with partial suspicion | Standard BSL-2 plus respiratory protection, all aerosol steps in the BSC, sealed centrifuge cups, dedicated marked space | Cuts inhalation risk sharply without a BSL-3 suite | Depends on discipline, does not satisfy containment expectations for agents that require BSL-3 | | BSL-3 containment culture | Suspected *B. anthracis*, *Coccidioides*, *Francisella*, *Brucella*, *Coxiella burnetii*, or HPAI virus culture | Negative-pressure directional airflow, respiratory protection, dedicated suite, controlled entry, specialized training | Meets containment expectations for high-consequence agents | Costly, slow, limited to equipped facilities, most routine laboratories lack it | | Inactivation plus molecular testing | Samples needing rapid answers at reduced containment | Validated chemical or physical inactivation, extraction controls, real-time PCR or LAMP-based detection | Faster, removes most downstream risk, allows lower-containment processing of high-hazard material | Viability stays unknown, matrix inhibition can cause false negatives, positives often need culture or reference confirmation | | Referral to a reference laboratory | Select-agent suspicion, outbreak support, missing containment or competency | Triple packaging, pre-arranged acceptance, chain of custody, hazard communication | Correct containment and expert confirmation guaranteed | Transit delay, coordination overhead, no local isolate for follow-up | ### Standard BSL-2 Culture of Routine Samples BSL-2 is the default containment level for environmental samples with no credible suspicion of a high-consequence agent. It assumes agents of moderate hazard and pairs standard microbiological practices with containment equipment. The bench rules are concrete: - Perform every open-tube step, including plating, streaking, and subculture, inside a certified Class II BSC. - Never pipette by mouth. Use mechanical pipettors with filtered tips. - Never sniff plates. Colony odor identification is a habit carried over from teaching labs, and with environmental unknowns it is a direct inhalation exposure. - Minimize sharps. If needles or glass slides are required, keep a puncture-resistant container inside the work zone. - Disinfect the cabinet surface before and after work with a freshly prepared disinfectant and allow the full contact time. - Autoclave all cultures before disposal and keep decontamination records. A typical *Legionella* water workflow shows these rules in action. Concentrate the sample, treat aliquots with heat and acid pretreatment to suppress competing flora, plate on buffered charcoal yeast extract (BCYE) agar, the selective medium for *Legionella*, with and without selective supplements, incubate, and confirm presumptive colonies by subculture onto BCYE lacking L-cysteine. Culture on BCYE remains the reference method for enumeration, and the same 1 L sample can support molecular testing run in parallel, which avoids a second collection round and a second exposure event [2]. ### Enhanced BSL-2: BSL-2 With BSL-3 Practices Enhanced BSL-2 keeps the BSL-2 facility but adds the work practices of a higher level. It fits dusty soils, samples from farms with active zoonotic disease, and any unknown that has raised partial suspicion without meeting the threshold for referral. Add these elements: - **Respiratory protection.** A fit-tested N95 respirator or a powered air-purifying respirator (PAPR) for dusty or high-load steps. Fit testing and a user seal check belong to a formal respirator program, not to optional extras. - **All manipulations in the BSC,** including vortexing with capped tubes and opening of centrifuge rotors. - **Sealed centrifuge safety cups or rotors,** loaded and unloaded inside the cabinet. - **Wet handling for soil.** Add sterile buffer before any manipulation that could puff dust. - **A dedicated, marked work area** with restricted access and dedicated PPE. - **A written stop rule.** Define in advance which observations, for example large gram-positive rods with endospores on a direct smear, halt work and trigger escalation. Enhanced BSL-2 is a discipline test. It fails when someone skips the respirator for a five-minute task or opens a rotor on the open bench to save time. Write the stop rule, post it, and hold to it. ### BSL-3 and High-Consequence Suspicion Biosafety Level 3 applies to agents that cause serious or potentially lethal disease and can spread through the airborne route. The facility adds directional airflow with negative pressure, a dedicated suite with controlled entry, respiratory protection, and specialized training with documented competency. For environmental work, the common triggers are: - ***Bacillus anthracis.*** Soil and animal-product samples from endemic areas or outbreak settings. Spores persist in soil and sustain transmission, which is why field-deployable detection tools for environmental spores remain an active research priority [1]. - ***Coccidioides* species.** Soil from endemic regions. The mycelial (mold) phase grown from soil poses the serious inhalation hazard, and its culture is handled at BSL-3. - ***Francisella tularensis*, *Brucella* species, and *Coxiella burnetii*** from animal-linked environmental samples. - **HPAI virus.** Work with live HPAI H5N1 must be conducted in containment level 3 laboratories because of the virus's high pathogenicity [4]. The stop rule matters most at this level. If a direct smear or early colony morphology from an environmental sample suggests a high-consequence agent, stop, secure the cultures, keep the cabinet running and decontaminate it, notify the supervisor and biosafety officer, and refer the material. In the United States, *B. anthracis* is regulated as a select agent, a category of biological agents whose possession, use, and transfer are federally controlled, and confirmed work with it carries facility and reporting requirements that no routine laboratory should improvise. ### Inactivation and Molecular Alternatives ![Worked calculation adding the 0.5 to 0.7 log10 gap to a culture count to show the qPCR count.](/article-images/illustrations/biosafety-environmental-samples-culturing-legionella-qpcr-gap.webp) Inactivation means destroying an agent's ability to replicate so the sample can be handled at a lower containment level. The catch is that inactivation must be validated for the specific agent in the specific matrix, because organic load, protein content, and the spore or biofilm state all change how a disinfectant performs. A current example comes from HPAI H5N1, which expanded its host range into dairy cattle with more than 1,000 reported US cases since March 2024 and 41 documented human spillover cases. Researchers evaluated inactivation protocols that would allow safe transfer of virus-containing materials from containment level 3 to containment level 2 laboratories. Beta-propiolactone, a chemical inactivant, at 0.1% and 0.2%, and Qiagen Buffer AVL with 95% ethanol completely inactivated HPAI in [cell culture media](/knowledge/diagnostics/microbiology/cell-culture-media-a-guide-to-selection-and-optimization) and in allantoic fluid, the nutrient-rich fluid from embryonated eggs used to propagate influenza viruses. The treated materials then supported downstream work such as ELISA, qPCR, and [RNA sequencing](/blog/guides/rna-sequencing) at the lower level [4]. The lesson generalizes: validated inactivation converts a containment problem into a scheduling problem. Molecular detection offers a second route, and three recent platforms show the range: - **Legionella.** Real-time PCR (qPCR, a fluorescent amplification method that reports results as the reaction runs) assays targeting the *ssrA*, *mip*, and *wzm* genes reached a sensitivity of 5 genome units per reaction with 100% specificity. Across 200 environmental water samples the assays showed a 100% negative predictive value, meaning a negative result reliably screened out culture-negative samples, and they ran on the same 1 L sample as culture. qPCR counts averaged 0.5 to 0.7 log10 higher than culture counts, consistent with detection of nonviable cells and extracellular DNA, which is why culture remains the gold standard for enumeration [2]. - ***B. anthracis* spores.** A LAMP-assisted CRISPR-Cas12a platform (LAMP is [loop-mediated isothermal amplification](/knowledge/diagnostics/molecular/lamp-assay-rapid-detection-african-swine-fever-virus-oral-fluids), a rapid nucleic acid amplification method, paired with a CRISPR-Cas12a sequence-specific reporter) reached detection limits of 10 spores per ml for the plasmid-encoded *lef* target and 100 spores per ml for a chromosomal target, with spore recovery of 50 to 75% in spiked soil and meat meal and field performance of 91.70% sensitivity and 100% specificity against a WOAH-recommended real-time PCR across 100 samples from endemic regions of India [1]. - ***Salmonella enterica* serovar Typhi.** SYBR Green real-time PCR (a dye-based qPCR chemistry) markers showed the *invA* gene amplifying in 90% of *Salmonella* isolates as a reliable genus-level marker, with serovar-level discrimination added by markers such as *phsB* and *tviA* [5]. The pros and cons line up clearly. Molecular routes are faster, remove many aerosol-generating culture steps, and can run at lower containment after validated inactivation. They cannot tell you whether the organism is alive, they can be inhibited by soil organic matter and other matrix components, and a positive result usually needs culture or reference confirmation before it drives decontamination or treatment decisions. ### Referral to a Reference Laboratory Referral is the correct option when suspicion involves a select agent or another high-consequence agent, when your facility lacks the containment, or when your staff lack documented competency for the sample type. Referral is a planned process, not a panicked shipment: 1. Call the receiving laboratory before sampling whenever possible and describe the suspicion honestly. 2. Package using triple packaging, meaning a sealed primary container wrapped with absorbent material inside a secondary container, all inside a rigid labeled outer box. 3. Ship through couriers and staff trained for biological material transport. 4. Maintain chain of custody documentation and keep copies of everything communicated. Referral keeps the hazard with the people equipped for it and protects your staff from the regulatory exposure of working an agent your facility is not approved to hold. ## How to Choose: The Criteria That Decide Real Cases ![Decision path from suspicion level to standard BSL-2, enhanced BSL-2, BSL-3 or referral to a reference laboratory.](/article-images/illustrations/biosafety-environmental-samples-culturing-containment-triage.webp) Four criteria separate these options in practice: - **Suspicion level.** No suspicion supports standard BSL-2. Partial suspicion supports enhanced BSL-2. Credible suspicion of a high-consequence agent supports BSL-3 or referral. - **Need for viability.** If you need a live isolate for susceptibility testing, typing, or outbreak linkage, inactivation and molecular-only routes are out. If you only need a name, molecular routes win on speed and safety. - **Turnaround.** Culture takes days to weeks, and that delay has documented consequences in outbreak response [2]. Inactivation plus qPCR or LAMP can return results the same day. - **Local capability.** Containment you do not have is containment you cannot use. Match the option to the cabinet, the suite, the respirator program, and the training records you can actually produce. ## Engineering Controls, Equipment, and Decontamination The Class II biosafety cabinet is the central engineering control. It protects the worker with inward airflow, protects the sample with HEPA-filtered (high-efficiency particulate air) laminar flow, and protects the room with filtered exhaust. Keep the front grille clear, work well inside the sash opening, minimize arm movement, and never disrupt the air curtain with rapid entry or open flames. Certification is an annual requirement, and a failed certification takes the cabinet out of service until it passes. Centrifugation deserves specific attention because it is the highest-energy step in most environmental protocols. Use sealed safety cups or sealed rotors, load and unload them inside the BSC, and after a run let the rotor rest before opening so any released aerosol can settle. If a breakage occurs inside a cup, treat the whole cup as contaminated and open it in the cabinet with disinfectant ready. Ultraviolet germicidal irradiation is a useful supplementary layer. A 254 nm UV-C multiemitter system deployed across eight hospital areas achieved mean aerobiome reductions above 91.5%, reduced surface contamination by 96.1%, and in vitro testing showed 99.99% to 100% elimination of planktonic microorganisms with complete loss of viability in mature biofilms regardless of biofilm architecture [6]. The limits are just as concrete: UV-C works by line of sight, so shaded and shadowed surfaces stay contaminated, and it does not penetrate organic soil. Treat UV-C as a complement to surface disinfection, never as a substitute. Chemical disinfection follows matrix rules. Freshly prepared sodium hypochlorite (household bleach diluted in water) is the workhorse for benches and spills, but it loses activity during storage, corrodes stainless steel, and needs a rinse-down to protect cabinet surfaces. Alcohols act fast on enveloped viruses but poorly on non-enveloped viruses and bacterial spores. Quaternary ammonium products handle routine surfaces but are not sporicidal. Match the agent to the worst plausible organism, not to the most convenient one. Autoclaving closes the loop. Standard cycles run at 121 °C with saturated steam, and cycle validity is confirmed with biological indicators containing *Geobacillus stearothermophilus* spores on a defined schedule. Keep written load records, because an autoclave record you cannot produce is a record that does not exist during an inspection. ## PPE and Aerosol Management PPE for routine environmental culture is gloves, a fluid-resistant laboratory gown, and eye protection. Escalate to an N95 or PAPR whenever the matrix generates dust or when suspicion rises. The aerosol rules matter more than the PPE list: - Keep soil wet. Add sterile buffer before any pouring, mixing, or vortexing. - Cap tubes before vortexing, and vortex inside the cabinet. - Open centrifuge rotors in the cabinet, never on the bench. - Pour, never flick, and keep transfer pipettes low to the surface. - Ban food, drink, gum, and cosmetics from the laboratory, and wash hands on exit. - Leave laboratory coats and respirators in the laboratory. Aerosol discipline is what turns a BSL-2 room into a safe room. PPE alone never compensates for a dry, dusty workflow on an open bench. ## Microbiology Biosafety Training Microbiology biosafety training is the administrative control that makes every other control work. A complete program for environmental sample work covers: - Risk assessment practice, not just risk assessment theory. - Exposure routes and how specific procedures generate aerosols. - Biosafety cabinet operation and the behaviors that ruin airflow. - Centrifuge safety, including sealed rotor handling and breakage response. - Spill response and exposure response, with drills. - Waste segregation, autoclave use, and record keeping. - Incident reporting, including near misses. Training research supports the integrated approach. A network analysis of biosafety incident response competence among 4,338 clinical nursing staff found that the components of competence form a connected structure, with correct specimen collection and handling practices among the central elements, so a weakness in one component propagates through the whole network [7]. Translated to the bench, a staff member who plates samples correctly but cannot respond to a spill is not partially competent. Assess competency by direct observation of the actual tasks, refresh it on a defined schedule, and document it in records an inspector can read. ## Spill and Exposure Response Spill response for an environmental sample follows a fixed sequence: 1. Alert everyone in the room and hold traffic. 2. Put on fresh PPE, including respiratory protection if the spill could generate aerosol from a dusty or liquid matrix. 3. Cover the spill with absorbent material and pour disinfectant from the perimeter inward. 4. Allow the full contact time before cleanup. 5. Collect broken glass with tongs or a dustpan, never with hands. 6. Disinfect the area again, then clean and disinfect the BSC if the spill happened inside it, including the drain pan beneath the work surface. 7. Report the spill and any exposure, and route exposed staff to occupational health for evaluation and follow-up. Practice the sequence before you need it. A spill drill with a harmless surrogate, for example a tube of sterile buffer with dye, exposes gaps in supplies and contact-time discipline without any risk. ## Worked Scenarios ### Scenario 1: Pasture soil with suspected anthrax A veterinary clinic receives soil from a pasture where cattle died suddenly. The risk assessment flags *B. anthracis* as plausible. The clinic does not culture the soil. Staff handle the sealed sample minimally in a Class II cabinet with gloves and gown, prepare a low-agitation smear only if local policy requires it, and refer the sample to the state public health or agricultural diagnostic laboratory with clear hazard communication. Field-deployable molecular tools for environmental spore detection continue to improve [1], but the clinic's decision does not change: no local culture of a suspected anthrax sample. ### Scenario 2: Cooling tower water for *Legionella* An environmental health team samples a cooling tower after a Legionnaires' disease case. This is a standard BSL-2 job. The team concentrates the water, splits it for culture and qPCR, performs heat and acid pretreatment, and plates on BCYE with and without supplements inside the cabinet. The qPCR result returns quickly, and its strong negative predictive performance lets the team screen out negative samples while culture proceeds [2]. Presumptive colonies are confirmed by subculture on cysteine-free BCYE, and the isolate supports the outbreak investigation. ### Scenario 3: Farm samples during an HPAI response A diagnostic laboratory receives milk and environmental swabs from a dairy herd during an H5N1 response. Live virus culture is not an option outside containment level 3 [4]. The laboratory instead uses a validated inactivation protocol of the kind shown to permit safe transfer to containment level 2, such as beta-propiolactone treatment or AVL-ethanol lysis [4], and then runs qPCR at the lower level. The inactivation validation is performed on the actual sample matrices before routine use. ### Scenario 4: Teaching cultures from garden soil A college course plates garden soil for a microbiology class. Standard BSL-2 applies with teaching-specific rules: pre-moisten the soil in a sealed container, plate inside the BSC, keep plates taped and closed, never open plates with mold colonies on the open bench, and never sniff plates. The instructor reviews the risk assessment each term because the soil source changes. ## Common Mistakes and Limitations These mistakes recur in environmental work: - **Sniffing plates.** The classic one. Colony odor identification is an inhalation exposure to an unknown aerosol, and with environmental samples the unknown list includes high-consequence agents. - **Treating "just soil" or "just water" as low risk.** The matrix and its history, not the paperwork, determine the hazard. - **Opening the centrifuge immediately after the run.** Aerosols need settling time, and sealed rotors belong in the cabinet when opened. - **Using yesterday's bleach.** Hypochlorite loses activity in storage, and a disinfectant without verified activity is decoration. - **Skipping inactivation validation for the actual matrix.** A method validated in clear buffer can fail in soil or allantoic fluid, so validation has to use the real material [4]. - **Treating a positive PCR as proof of viable organisms.** Molecular targets persist after cell death, which is exactly why culture remains the enumeration reference for *Legionella* [2]. - **Dry handling of soil on an open bench.** Dust is the aerosol you cannot see. - **Working alone with unknown samples.** The buddy rule is an exposure control, not a formality. - **Training that covers paperwork but not hands-on competency.** Records without observed skills do not protect anyone. On limitations: this guide states general bench practice, not a ruling for a specific sample. Individual cases need review by a biosafety officer or a qualified microbiologist, and institutional SOPs plus federal requirements take precedence over any general article. ## Frequently Asked Questions ### What containment level do I need to culture routine soil and water samples? Biosafety Level 2 is the default for routine environmental cultures with no suspicion of high-consequence agents. Escalate to BSL-3 practices or full BSL-3 containment, or refer the sample, when agents such as *Bacillus anthracis* or highly pathogenic avian influenza virus are plausible. ### Can I plate environmental samples on an open bench if I wear gloves? No. Gloves do not protect you from aerosols and dust, which are the main exposure routes for environmental matrices. Perform every open-tube and plating step in a certified Class II biosafety cabinet. ### How can I test an environmental sample for pathogens without culturing it? Use validated inactivation followed by molecular detection such as qPCR or LAMP-based assays. Inactivation must be validated for the specific agent and matrix, because a method that works in clear buffer can fail in soil or organic debris. ### When should an environmental sample go to a reference laboratory instead of my bench? Send it whenever you suspect a high-consequence or select agent, when your facility lacks the required containment, or when your staff lack documented competency. Arrange acceptance and packaging with the receiving laboratory before the sample ships. ### What should microbiology biosafety training cover before staff culture environmental samples? Training should cover risk assessment, exposure routes, biosafety cabinet operation, centrifuge safety, spill and exposure response, and waste handling, with hands-on competency assessment rather than paperwork alone. These components work as a connected set, so a gap in one area undermines the others [7]. ### Does UV-C light replace chemical disinfection in the culture laboratory? No. UV-C systems reduce surface and airborne bioburden and work as a supplementary layer, but they do not replace fresh chemical disinfectants and validated autoclave cycles. Line-of-sight limits leave shaded surfaces that only liquid disinfection reaches. ## Sources 1. [LAMP-assisted CRISPR-Cas12a platform for detection of Bacillus anthracis spores in environmental samples.](https://pubmed.ncbi.nlm.nih.gov/42618112/) 2. [Real-time PCR to supplement gold-standard culture-based detection of Legionella in environmental samples.](https://pubmed.ncbi.nlm.nih.gov/26218315/) 3. [A cross-border comparison reveals expanded microbial diversity and zoonotic risk in Rhipicephalus microplus ticks of Yunnan, China.](https://pubmed.ncbi.nlm.nih.gov/43004464/) 4. [Evaluation of beta-propiolactone and AVL-ethanol inactivation protocols for highly pathogenic avian influenza virus in allantoic fluid and cell culture.](https://pubmed.ncbi.nlm.nih.gov/41733352/) 5. [Evaluation of gene markers invA, phsB, and tviA for detection of Salmonella Typhi by SYBR Green (TM) real-time PCR assay in clinical samples.](https://pubmed.ncbi.nlm.nih.gov/42584516/) 6. [Impact of a UV-C Multiemitter Disinfection System on Hospital Environmental Bioburden and Inactivation of Clinically Relevant Pathogens.](https://pubmed.ncbi.nlm.nih.gov/41901700/) 7. [The relationship between components of the biosafety incident response competence for clinical nursing staff: a network analysis.](https://pubmed.ncbi.nlm.nih.gov/41068611/)