A comprehensive technology strategy for microbial identification and contamination investigation in the sterile drug manufacturing facility-a case study

Objective

A comprehensive strategy for microbial identification and contamination investigation during sterile drug manufacturing was innovatively established in this study, mainly based on MALDI-TOF MS for the identification and complemented by sequencing technology on strain typing.

Methods

It was implemented to monitor the bacterial contamination of a sterile drug manufacturing facility, including its bacterial distribution features and patterns. In three months, two hundred ninety-two samples were collected covering multiple critical components of raw materials, personnel, environment, and production water.

Results

Based on our strategy, the bacterial profile across the production process was determined: 241/292 bacterial identities were obtained, and Staphylococcus spp. (40.25%), Micrococcus spp.(11.20%), Bacillus spp. (8.30%), Actinobacteria (5.81%), and Paenibacillus spp. (4.56%) are shown to be the most dominant microbial contaminants. With 75.8% species-level and 95.4% genus-level identification capability, MALDI-TOF MS was promising to be a first-line tool for environmental monitoring routine. Furthermore, to determine the source of the most frequently occurring Staphylococcus cohnii, which evidenced a widespread presence in the entire process, a more discriminating S. cohnii whole-genome SNP typing method was developed to track the transmission routes. Phylogenetic analysis based on SNP results indicated critical environment contamination is highly relevant to personnel flow in this case. The strain typing results provide robust and accurate information for the following risk assessment step and support effective preventive and corrective measures.

Conclusion

In general, the strategy presented in this research will facilitate the development of improved production and environmental control processes for the pharmaceutical industry, and give insights about how to provide more sound and reliable evidence for the optimization of its control program.

Assessing the impact of sanitization methods for regenerated cellulose ultrafiltration/diafiltration membrane on membrane integrity and protein quality

Ultrafiltration/diafiltration (UF/DF) is typically the final step in downstream processing of recombinant monoclonal antibody (mAb) products, which serves for protein concentration and buffer exchange. For UF/DF membranes composed of regenerated cellulose (RC), sanitization with 0.1 M sodium hydroxide is generally recommended by the supplier, but it may not be sufficient for reducing bioburden during large scale manufacturing. Therefore, more stringent sanitization methods for RC membranes are required. However, chemicals used in such sanitization step may disrupt membrane integrity, while the corresponding residuals may reduce product quality. Previous work has shown that high concentration of sodium hydroxide or addition of peracetic acid (PAA) can effectively reduce bioburden, but their effects on the RC membranes remain unknown. In this work, we assessed the impact of two sanitization methods, 0.5 M sodium hydroxide and 30 mM PAA in combination with 0.5 M sodium hydroxide, on membrane integrity and protein quality of Millipore and pall corporation (PALL) membranes. Both methods showed a similar impact as the control after performing 15 cycles. However, the addition of PAA may cause residual chemical concerns, therefore, 0.5 M sodium hydroxide was recommended as an effective and safe sanitization method for RC UF/DF membranes.

Evaluation of MALDI-TOF MS, sequencing of D2 LSU rRNA and internal transcribed spacer regions (ITS) for the identification of filamentous fungi isolated from a pharmaceutical facility

The identification of filamentous fungi through culture characterization may be hampered by phenotypic variability. Information obtained from the identification of microorganisms are important for investigation of sources of contamination of a product or process. The aim of this study was to identify filamentous fungal strains (n = 50) isolated from a pharmaceutical facility by using Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS), as well as D2 domain of the large-subunit (LSU) ribosomal RNA gene and internal transcribed spacer regions (ITS) sequencing. MALDI-TOF MS system only identified five strains at the species level, while 45 were not identified. The analysis through GenBank allowed the identification of up to 19 strains at the species level, while MycoBank allowed the identification of up to nine strains at the species level. The databases identified up to 11 genera: Penicillium, Aspergillus, Cladosporium, Chaetomium, Coniochaeta, Curvularia, Diaporthe, Fusarium, Trichoderma, Rhizopus and Microdochium. MALDI-TOF MS showed an insufficient database to identify the species of fungi. DNA sequencing was the best methodology to identify to the genus level but was unable to differentiate between closely related species. Therefore further methods for the identification of filamentous fungi from pharmaceutical areas at species level need to be developed.

The role of melanin in Aspergillus tolerance to biocides and photosensitizers

Cationic biocides are widely utilized for surface disinfection. Photosensitizers such as toluidine blue O (TBO) produce reactive oxygen species following light excitation and are being investigated as novel biocides for similar applications. Aspergillus brasiliensis conidia contain melanin which protects against environmental stressors. The negative charge and antioxidant properties of melanin may confer resistance to photosensitizers and other biocides. In this study, the yeasticidal and fungicidal activity benzalkonium chloride (BZC), sodium dichloroisocyanurate (NaDCC) and TBO with red light were examined using quantitative suspension tests. All three biocides were highly effective against Candida albicans and > 5·0 log₁₀ reductions in viability were attainable within 5 minutes. Wild-type A. brasiliensis conidia were highly tolerant to treatment and 0·4 log₁₀ reductions in viability were observed within the same time frame when treated with TBO or BZC. NaDCC was markedly more effective. Inhibition of melanin biosynthesis by culturing with 100 μg ml^-1 kojic acid resulted in a hypopigmented phenotype with significantly increased sensitivity to all three biocides. These observations indicate that melanin is a significant contributor towards A. brasiliensis tolerance of biocides and photosensitizers and demonstrate that cationic biocides are poorly suited to applications where the control of A. brasiliensis is required.

Healthcare-associated fungal outbreaks: New and uncommon species, New molecular tools for investigation and prevention

Outbreaks of healthcare-associated fungal infections have repeatedly been described over recent years, often caused by new or uncommon species. Candida auris, a recently described multidrug-resistant yeast species, is certainly the most worrisome species having caused several severe healthcare outbreaks of invasive infections, on four continents. Also, large nosocomial outbreaks due to uncommon fungal species such as Exserohilum rostratum and Sarocladium kiliense, were both linked to contamination of medical products, however the source of another outbreak, caused by Saprochaete clavata, remains unresolved. Furthermore, these outbreaks identified new populations under threat in addition to those commonly at risk for invasive fungal infections, such as immunosuppressed and intensive care unit patients. All of these outbreaks have highlighted the usefulness of a high level of awareness, rapid diagnostic methods, and new molecular typing tools such as Whole Genome Sequencing (WGS), prompt investigation and aggressive interventions, including notification of public health agencies. This review summarizes the epidemiological and clinical data of the majority of healthcare-associated outbreaks reported over the last 6 years caused by uncommon or new fungal pathogens, as well as the contribution of WGS as support to investigate the source of infection and the most frequent control measures used.