Rapid detection of smear-negative Mycobacterium tuberculosis by PCR and sequencing for rifampin resistance with DNA extracted directly from slides

Concomitant hepatic tuberculosis and hepatocellular carcinoma: a case report and review of the literature

BACKGROUND

Hepatocellular carcinoma (HCC) is the most common primary liver malignancy that is strongly associated with chronic liver disease. Isolated hepatic tuberculosis is an uncommon type of tuberculosis. Concomitant occurrence of both conditions is extremely rare.

CASE PRESENTATION

We report the case of a 47-year-old man who presented with fever and abdominal pain for 3 months prior to presentation. He reported a history of anorexia and significant weight loss. Abdominal examination revealed a tender, enlarged liver. Abdominal computed tomography (CT) demonstrated a solid heterogeneous hepatic mass with peripheral arterial enhancement, but no venous washout, conferring a radiological impression of suspected cholangiocarcinoma. However, a CT-guided biopsy of the lesion resulted in the diagnosis of concomitant HCC and isolated hepatic tuberculosis.

CONCLUSION

A rapid increase in tumor size should draw attention to the possibility of a concomitant infectious process. Clinicians must have a high index of suspicion for tuberculosis, especially in patients from endemic areas, in order to initiate early and proper treatment.

Application of next generation sequencing-based rapid detection platform for microbiological diagnosis and drug resistance prediction in acute lower respiratory infection

Background

Acute lower respiratory infections (ALRIs) have a high mortality rate. We aimed to apply a platform that rapidly detects 36 microorganisms and 49 antibiotic resistance markers in the clinical diagnosis of ALRI and drug resistance prediction.

Methods

Multicenter collection of clinical samples from patients with ALRIs was carried out from 2017 to 2018. Sputum culture (SC) was performed, which provided two outcomes: the detected pathogens and the resistance to different antibiotics. Additionally, each sputum sample was used to extract deoxyribonucleic acids (DNAs) followed by high-throughput sequencing.

Results

Eleven commonly observed pathogens were surveyed, and for all samples with positive SC results (137 cases), the overall coverage was 95.62% according to the sequencing results. The receiver operating characteristic (ROC) curve was drawn, and cutoff reads of the most frequently detected pathogens were acquired. Overall, sequencing exhibited significantly higher sensitivity in the detection of pathogens compared with the traditional SC method, with a generally satisfactory specificity. Furthermore, we investigated the correlation between antibiotic resistance gene phenotypes and the actual outcomes of the drug sensitivity test, and some significant correlations were found, especially for the resistance to Amikacin in the presence of blaOXA7.

Conclusions

Sequencing-based sputum metagenomics can reveal a profile of the lung pathogen microbiome. The sequencing method offers both sufficient accuracy and significantly higher sensitivity in the detection of pathogens, and can be at least a complementary approach to traditional SC reporting. The sequencing technique also revealed some novel potential correlations between the presence of different pathogens, as well as new antimicrobial-resistant genes.

Detection of drug resistant Mycobacterium tuberculosis by high-throughput sequencing of DNA isolated from acid fast bacilli smears

BACKGROUND

Drug susceptibility testing for Mycobacterium tuberculosis (MTB) is difficult to perform in resource-limited settings where Acid Fast Bacilli (AFB) smears are commonly used for disease diagnosis and monitoring. We developed a simple method for extraction of MTB DNA from AFB smears for sequencing-based detection of mutations associated with resistance to all first and several second-line anti-tuberculosis drugs.

METHODS

We isolated MTB DNA by boiling smear content in a Chelex solution, followed by column purification. We sequenced PCR-amplified segments of the rpoB, katG, embB, gyrA, gyrB, rpsL, and rrs genes, the inhA, eis, and pncA promoters and the entire pncA gene.

RESULTS

We tested our assay on 1,208 clinically obtained AFB smears from Ghana (n = 379), Kenya (n = 517), Uganda (n = 262), and Zambia (n = 50). Coverage depth varied by target and slide smear grade, ranging from 300X to 12000X on average. Coverage of ≥20X was obtained for all targets in 870 (72%) slides overall. Mono-resistance (5.9%), multi-drug resistance (1.8%), and poly-resistance (2.4%) mutation profiles were detected in 10% of slides overall, and in over 32% of retreatment and follow-up cases.

CONCLUSION

This rapid AFB smear DNA-based method for determining drug resistance may be useful for the diagnosis and surveillance of drug-resistant tuberculosis.

A rapid and sensitive system for recovery of nucleic acids from Mycobacteria sp. on archived glass slides

BACKGROUND

The field of diagnostics continues to advance rapidly with a variety of novel approaches, mainly dependent upon high technology platforms. Nonetheless much diagnosis, particularly in developing countries, still relies upon traditional methods such as microscopy. Biological material, particularly nucleic acids, on archived glass slides is a potential source of useful information both for diagnostic and epidemiological purposes. There are significant challenges faced when examining archived samples in order that an adequate amount of amplifiable DNA can be obtained. Herein, we describe a model system to detect low numbers of bacterial cells isolated from glass slides using (laser capture microscopy) LCM coupled with PCR amplification of a suitable target.

RESULTS

Mycobacterium smegmatis was used as a model organism to provide a proof of principle for a method to recover bacteria from a stained sample on a glass slide using a laser capture system. Ziehl-Neelsen (ZN) stained cells were excised and catapulted into tubes. Recovered cells were subjected to DNA extraction and pre-amplified with multiple displacement amplification (MDA). This system allowed a minimum of 30 catapulted cells to be detected following a nested real-time PCR assay, using rpoB specific primers. The combination of MDA and nested real-time PCR resulted in a 30-fold increase in sensitivity for the detection of low numbers of cells isolated using LCM.

CONCLUSIONS

This study highlights the potential of LCM coupled with MDA as a tool to improve the recovery of amplifiable nucleic acids from archived glass slides. The inclusion of the MDA step was essential to enable downstream amplification. This platform should be broadly applicable to a variety of diagnostic applications and we have used it as a proof of principle with a Mycobacterium sp. model system.

Rapid detection of rpoB mutations in rifampin resistant M. tuberculosis from sputum samples by denaturing gradient gel electrophoresis

OBJECTIVE

To establish a rapid detection method for identifying rpoB mutations associated with rifampin (RIF) resistance in sputum specimens.

METHODS

We detected rpoB mutations directly in 90 sputum specimens collected from suspected tuberculosis patients using PCR-based denaturing gradient gel electrophoresis (DGGE) and compared these results with those obtained by rpoB sequencing and conventional drug susceptibility testing.

RESULTS

The positive detection rate of Mycobacterium tuberculosis (M. tuberculosis) was 52.2% by Acid-Fast Bacilli staining and 72.2% by conventional mycobacterial culture. In contrast, the positive rate was significantly higher (93.3%) by PCR-based detection of the rpoB gene in the same specimens. Furthermore, 75% of the tested specimens presented abnormal patterns compared with the wild-type pattern (standard H37Rv strain) analysed by DGGE. A total of 12 different patterns, representing 12 different rpoB mutations, were observed in the 63 abnormal patterns. The match rate of rpoB mutations detected by DGGE reached 96.9% when compared to DNA sequencing.

CONCLUSION

Our findings indicate that PCR-based DGGE is a rapid and reliable bio-technique for direct detection of rpoB mutations associated with RIF resistance in the sputum of suspected tuberculosis patients.

Rapid identification of mycobacteria and drug-resistant Mycobacterium tuberculosis by use of a single multiplex PCR and DNA sequencing

Tuberculosis (TB) remains a significant global health problem for which rapid diagnosis is critical to both treatment and control. This report describes a multiplex PCR method, the Mycobacterial IDentification and Drug Resistance Screen (MID-DRS) assay, which allows identification of members of the Mycobacterium tuberculosis complex (MTBC) and the simultaneous amplification of targets for sequencing-based drug resistance screening of rifampin-resistant (rifampin(r)), isoniazid(r), and pyrazinamide(r) TB. Additionally, the same multiplex reaction amplifies a specific 16S rRNA gene target for rapid identification of M. avium complex (MAC) and a region of the heat shock protein 65 gene (hsp65) for further DNA sequencing-based confirmation or identification of other mycobacterial species. Comparison of preliminary results generated with MID-DRS versus culture-based methods for a total of 188 bacterial isolates demonstrated MID-DRS sensitivity and specificity as 100% and 96.8% for MTBC identification; 100% and 98.3% for MAC identification; 97.4% and 98.7% for rifampin(r) TB identification; 60.6% and 100% for isoniazid(r) TB identification; and 75.0% and 98.1% for pyrazinamide(r) TB identification. The performance of the MID-DRS was also tested on acid-fast-bacterium (AFB)-positive clinical specimens, resulting in sensitivity and specificity of 100% and 78.6% for detection of MTBC and 100% and 97.8% for detection of MAC. In conclusion, use of the MID-DRS reduces the time necessary for initial identification and drug resistance screening of TB specimens to as little as 2 days. Since all targets needed for completing the assay are included in a single PCR amplification step, assay costs, preparation time, and risks due to user errors are also reduced.

Rapid identification of multidrug-resistant Mycobacterium tuberculosis isolates by rpoB gene scanning using high-resolution melting curve PCR analysis

BACKGROUND

Multidrug-resistant (MDR) Mycobacterium tuberculosis poses a serious threat to the control of tuberculosis (TB) and constitutes an increasing public health problem. The availability of rapid in vitro susceptibility tests is a prerequisite for optimal patient treatment. Rifampicin resistance caused by diverse mutations in the rpoB gene is an established and widely used surrogate marker for MDR-TB. We used a high-resolution melting (HRM) curve analysis approach to scan for mutations in the rpoB gene.

METHODS

A total of 49 MDR-TB and 19 fully susceptible non-MDR-TB isolates, as determined by conventional drug susceptibility testing using the BACTEC-MGIT960 system, were used to evaluate the suitability of HRM curve analysis as a rapid and accurate screening system for rifampicin resistance.

RESULTS

HRM analysis of the rpoB cluster I site allowed the correct allocation of 44 of the 49 MDR-TB isolates and all non-MDR-TB isolates. Three of the five MDR-TB isolates (60%) falsely identified as non-MDR-TB harboured the V176F mutation that could be specifically detected by an additional HRM assay. The combined HRM analysis of all strains and isolates exhibited 95.9% sensitivity and 100% specificity.

CONCLUSIONS

With a positive predictive value of 100% and a negative predictive value of at least 99.9%, this combined HRM curve analysis is an ideal screening method for the TB laboratory, with minimal requirements of cost and time. The method is a closed-tube assay that can be performed in an interchangeable 96- or 384-well microplate format enabling a rapid, reliable, simple and cost-effective handling of even large sample numbers.

Rapid detection of rifampin-resistant Mycobacterium tuberculosis directly from stained sputum smears using single-tube nested polymerase chain reaction deoxyribonucleic acid sequencing

Microscopy is the mainstay of laboratory diagnosis of tuberculosis especially in resource poor countries. The World Health Organization has also recommended microscopy as the mainstay of diagnosis for directly observed treatment, short course. Using DNA extracts from Ziehl-Neelsen (ZN)-stained sputum smears, a single-tube nested polymerase chain reaction was optimized to confirm Mycobacterium tuberculosis complex and detect rifampin (RIF) resistance by sequencing, using a combination of novel (rpoB47 and rpoB158) and previously described (rpoB105 and rpoB293) primers. Carryover DNA was strictly monitored using several negative controls, and inhibition was ruled out by spiked controls. No such target was detected from negative controls and purified genomic DNA from other nontubercular mycobacteria. Resistance could be detected in 91.1% (51/56) slides. The results obtained were concordant with the 1% proportion method and DNA sequencing performed on culture isolates. Our results demonstrate that the method is suitable for rapid detection of susceptibility to RIF in acid-fast bacillus-positive ZN-stained slides obtained from patients suspected of harboring drug-resistant M. tuberculosis.

Leishmania identification by PCR of Giemsa-stained lesion imprint slides stored for up to 36 years

This study examined the ability of PCR to amplify Leishmania DNA, stored on Giemsa-stained slides, from American cutaneous leishmaniasis (ACL) patients. In total, 475 slides stored for up to 36 years were obtained from an outpatient clinic in a Brazilian ACL-endemic region, and Leishmania DNA was amplified from 395 (83.2%) of the DNA samples using primers specific for the minicircle kinetoplast DNA. Restriction fragment length polymorphism analysis of these amplicons demonstrated that Leishmania (Viannia) braziliensis was the only species present in these samples. The results demonstrated that archived Giemsa-stained slides can provide a Leishmania DNA source for performing clinical and epidemiological studies of leishmaniasis.

Coexistent Cervical Tuberculosis and Metastatic Squamous Cell Carcinoma in a Single Lymph Node Group: A Diagnostic Dilemma

Primary cervical tuberculosis is uncommon, although its incidence has risen somewhat over the past few years. In this article, we describe a rare case in which the patient developed a dual pathology—cervical tuberculosis and a malignant squamous cell carcinoma—in a group of lymph nodes on one side of the neck. Initially, tuberculosis was diagnosed on the basis of histology and culture. However, when the patient did not respond to antituberculous drug therapy, a repeat biopsy detected the second pathology: squamous cell carcinoma. To the best of our knowledge, no such presentation has been previously reported in the world literature. We conclude that repeat biopsy might be required in cases of tuberculous cervical lymphadenopathy that do not respond to conventional antituberculous therapy.

Multidrug-resistant tuberculosis detection, Latvia

To improve multidrug-resistant tuberculosis (MDR-TB) detection, we successfully introduced the rpoB gene mutation line probe assay into the national laboratory in Latvia, a country with epidemic MDR-TB. The assay detected rifampin resistance with 91% sensitivity and 96% specificity within 1 to 5 days (vs. 12–47 days for BACTEC).

In-house nucleic acid amplification tests for the detection of Mycobacterium tuberculosis in sputum specimens: meta-analysis and meta-regression

BACKGROUND

More than 200 studies related to nucleic acid amplification (NAA) tests to detect Mycobacterium tuberculosis directly from clinical specimens have appeared in the world literature since this technology was first introduced. NAA tests come as either commercial kits or as tests designed by the reporting investigators themselves (in-house tests). In-house tests vary widely in their accuracy, and factors that contribute to heterogeneity in test accuracy are not well characterized. Here, we used meta-analytical methods, including meta-regression, to identify factors related to study design and assay protocols that affect test accuracy in order to identify those factors associated with high estimates of accuracy.

RESULTS

By searching multiple databases and sources, we identified 2520 potentially relevant citations, and analyzed 84 separate studies from 65 publications that dealt with in-house NAA tests to detect M. tuberculosis in sputum samples. Sources of heterogeneity in test accuracy estimates were determined by subgroup and meta-regression analyses. Among 84 studies analyzed, the sensitivity and specificity estimates varied widely; sensitivity varied from 9.4% to 100%, and specificity estimates ranged from 5.6% to 100%. In the meta-regression analysis, the use of IS6110 as a target, and the use of nested PCR methods appeared to be significantly associated with higher diagnostic accuracy.

CONCLUSION

Estimates of accuracy of in-house NAA tests for tuberculosis are highly heterogeneous. The use of IS6110 as an amplification target, and the use of nested PCR methods appeared to be associated with higher diagnostic accuracy. However, the substantial heterogeneity in both sensitivity and specificity of the in-house NAA tests rendered clinically useful estimates of test accuracy difficult. Future development of NAA-based tests to detect M. tuberculosis from sputum specimens should take into consideration these findings in improving accuracy of in-house NAA tests.

rpoBGene Mutations in Clinical Isolates of Multidrug-ResistantMycobacterium tuberculosisin Northern Lima, Peru

In many developing countries and outside hospital settings, the characteristics of endemic Mycobacterium tuberculosis strains resistant to multiple drugs remain unknown. In a community-based referral and therapy program in northern Lima, Peru, beginning in 1996, patients found to be failures on standard regimens were referred for drug-susceptibility testing of their isolates, and those found to be infected with M. tuberculosis isolates resistant to at least rifampin were treated with individualized regimens based on their infecting strains. Isolates from 42 of these patients were subjected to DNA sequencing of the rpoB gene region responsible for rifampin resistance. We determined the frequency of types of mutations in the rpoB gene among these Peruvian isolates.

Rapid direct detection of multiple rifampin and isoniazid resistance mutations in Mycobacterium tuberculosis in respiratory samples by real-time PCR

Rapid detection of resistance in Mycobacterium tuberculosis can optimize the efficacy of antituberculous therapy and control the transmission of resistant M. tuberculosis strains. Real-time PCR has minimized the time required to obtain the susceptibility pattern of M. tuberculosis strains, but little effort has been made to adapt this rapid technique to the direct detection of resistance from clinical samples. In this study, we adapted and evaluated a real-time PCR design for direct detection of resistance mutations in clinical respiratory samples. The real-time PCR was evaluated with (i) 11 clinical respiratory samples harboring bacilli resistant to isoniazid (INH) and/or rifampin (RIF), (ii) 10 culture-negative sputa spiked with a set of strains encoding 14 different resistance mutations in 10 independent codons, and (iii) 16 sputa harboring susceptible strains. The results obtained with this real-time PCR design completely agreed with DNA sequencing data. In all sputa harboring resistant M. tuberculosis strains, the mutation encoding resistance was successfully detected. No mutation was detected in any of the susceptible sputa. The test was applied only to smear-positive specimens and succeeded in detecting a bacterial load equivalent to 10(3) CFU/ml in sputum samples (10 acid-fast bacilli/line). The analytical specificity of this method was proved with a set of 14 different non-M. tuberculosis bacteria. This real-time PCR design is an adequate method for the specific and rapid detection of RIF and INH resistance in smear-positive clinical respiratory samples.

Direct detection of rifampin- and isoniazid-resistant Mycobacterium tuberculosis in auramine-rhodamine-positive sputum specimens by real-time PCR

Our objective was to evaluate the feasibility of a molecular assay based on a real-time PCR technique, carried out with a LightCycler instrument (Roche Biochemicals), to identify Mycobacterium tuberculosis bacilli and to detect rifampin and isoniazid resistance in DNA extracts from sputum samples. We studied three genes: rpoB, which is associated with rifampin resistance, and katG and inhA, which are associated with isoniazid resistance. A total of 205 sputum samples collected from 108 patients diagnosed with pulmonary tuberculosis with positive auramine-rhodamine-staining (AR) sputum samples, were tested. The sensitivities of the LightCycler PCR assay for the positive AR specimens was 97.5% (200 of 205) for rpoB and inhA genes and 96.5% (198 of 205) for the katG gene. For the total number of patients tested, the sensitivity was 100% (108 of 108 patients) for rifampin, whereas the sensitivity was 98.1% (106 of 108 patients) for isoniazid. Full agreement was found with the Bactec MGIT 960 method and the genotype inferred from the LightCycler data for rifampin. The phenotypic method for isoniazid reported 13 resistant strains (> or = 0.1 microg/ml). In seven (53.8%) strains there was a concordance between both methods, but we found that six (46.2%) strains reported as resistant by the phenotypic method were determined to be susceptible by real-time PCR. For the 75 strains reported as susceptible by the phenotypic method, the concordance with the LightCycler data was 100%. Our results demonstrate that rifampin-resistant M. tuberculosis could be detected in DNA extracted from auramine-rhodamine-positive sputum samples in a single-tube assay that took less than 3 h to perform for a collection of auramine-rhodamine-positive specimens obtained from patients with culture-documented pulmonary tuberculosis. Similarly, this occurs in half of the isoniazid-resistant M. tuberculosis DNA extracted from auramine-rhodamine-positive specimens.

DNA extraction and quantification from touch and scrape preparations obtained from autopsy liver cells

The objective of the present study was to develop a simplified low cost method for the collection and fixation of pediatric autopsy cells and to determine the quantitative and qualitative adequacy of extracted DNA. Touch and scrape preparations of pediatric liver cells were obtained from 15 cadavers at autopsy and fixed in 95% ethanol or 3:1 methanol:acetic acid. Material prepared by each fixation procedure was submitted to DNA extraction with the Wizard genomic DNA purification kit for DNA quantification and five of the preparations were amplified by multiplex PCR (azoospermia factor genes). The amount of DNA extracted varied from 20 to 8,640 microg, with significant differences between fixation methods. Scrape preparation fixed in 95% ethanol provided larger amount of extracted DNA. However, the mean for all groups was higher than the quantity needed for PCR (50 ng) or Southern blot (500 ng). There were no qualitative differences among the different material and fixatives. The same results were also obtained for glass slides stored at room temperature for 6, 12, 18 and 24 months. We conclude that touch and scrape preparations fixed in 95% ethanol are a good source of DNA and present fewer limitations than cell culture, tissue paraffin embedding or freezing that require sterile material, culture medium, laboratory equipment and trained technicians. In addition, they are more practical and less labor intensive and can be obtained and stored for a long time at low cost.

Assessment by meta-analysis of PCR for diagnosis of smear-negative pulmonary tuberculosis

We conducted a meta-analysis to assess the performance of PCR for the diagnosis of smear-negative pulmonary tuberculosis (SPT) and to identify factors that account for differences in the diagnostic accuracy of different studies. Studies published before February 2002 were included if sensitivity and specificity of PCR in smear-negative respiratory or gastric-aspirate specimens could be calculated. Analysis was conducted by using summary receiver operating characteristics models. Sensitivity and specificity ranged from 9 to 100% and from 25 to 100%, respectively. Fewer than 40% of the 50 studies reported results by number of patients, reported clinical characteristics of patients, or used as a reference standard combined culture and clinical criteria. Studies that included bronchial specimens showed higher accuracy than studies that evaluated only sputum specimens or included gastric aspirates. Studies that did not report that tests were applied blindly showed higher accuracy than those reporting blind testing. Increased sensitivity due to the use of DNA purification methods was associated with decreased specificity. Studies published after 1995, using Amplicor or dUTP-UNG, were associated with an increase in specificity at the expense of lower sensitivity. We concluded that PCR is not consistently accurate enough to be routinely recommended for the diagnosis of SPT. However, PCR of bronchial specimens could be useful in highly suspicious SPT cases. Studies not reporting blind testing are likely to overestimate accuracy of PCR. Future evaluation of PCR accuracy should be conducted by patient and type of respiratory specimen, blindly, by using a reference standard that combines culture and clinical criteria and addresses the issue of how patient characteristics affect PCR accuracy.

Rapid detection of pulmonary tuberculosis using the BDProbeTEC ET Mycobacterium tuberculosis Complex Direct Detection Assay (DTB)

The ability to rapidly detect tubercle bacilli in respiratory secretions was determined for the BDProbeTEC ET Mycobacterium tuberculosis Complex Direct Detection Assay in comparison with the acid-fast smear (AFS). A total of 267 respiratory specimens obtained from 89 patients were evaluated. The DTB assay was positive in 70 of 78 culture positive specimens (89.7%) and 12 of 177 culture negative specimens (6.8%). The AFS was positive in 33 of 78 culture positive specimens (42.3%) and 3 of 186 culture negative specimens (1.6%). The sensitivity, specificity, positive predictive value, and negative predictive value of DTB assay were 89.7%, 93.7%, 85.4%, and 95.7%, respectively. The sensitivity of a single DBT (74.4%) was 2.1-times greater than three AFS (35.9%). The greater cost of the DTB assay compared to the AFS was compensated by its valuable information for the diagnosis and control of tuberculosis. These results demonstrated the clinical usefulness of the DTB assay for the rapid diagnosis of tuberculosis in respiratory specimens.

Use of DNA extracts from Ziehl-Neelsen-stained slides for molecular detection of rifampin resistance and spoligotyping of Mycobacterium tuberculosis

Multidrug resistance among new cases of tuberculosis (TB) is increasingly becoming a significant problem in countries with a high prevalence of TB and with inadequate therapies for TB. Rifampin resistance is widely used as a marker for multidrug-resistant (MDR) TB; therefore, a new approach to the retrospective measurement of rifampin resistance without the need of a viable culture has been introduced. In many developing countries culture is unavailable and diagnosis relies on clinical manifestations and the results of Ziehl-Neelsen staining of sputum smears. We determined rifampin resistance directly with DNA extracts from Ziehl-Neelsen-stained slides by identification of mutations in the rpoB gene using reverse line blot hybridization and DNA sequencing. Analysis of the rpoB gene revealed that samples containing rifampin-resistant Mycobacterium tuberculosis carried altered codons representing amino acid positions 516, 526, and 531 of the RNA polymerase. Although the sensitivities of both methods were equal (84%), sequencing of the rpoB gene was more accurate in identifying mutations in the core region of the rpoB gene. Sequence analysis of the rpoB gene in extracts from Ziehl-Neelsen-stained slides may be used to quantify more precisely the magnitude of MDR TB and, more importantly, provide information on trends in the development of resistance on a global scale. The nature of rifampin resistance and the genotype can be determined by analysis of Ziehl-Neelsen-stained slides in a laboratory equipped for sequencing and spoligotyping without the need to ship biohazardous materials.