- Volume 5, Issue 1, 2023

A toxin complex consists of a high-molecular-weight group of toxins that exhibits insecticidal activity against insect pests. These toxins are a promising alternative to Bacillus thuringiensis (Bt) toxins that have been extensively utilized in insect pest control. Herein, a codon-optimized insecticidal gene (tccZ) (381 bp) identified in Pantoea ananatis strain MHSD5 (a bacterial endophyte previously isolated from Pellaea calomelanos) was ligated into the pET SUMO expression vector and expressed in Escherichia coli BL21 (DE3). We report the success of cloning the tccZ gene into the pET SUMO vector and ultimately the transformation into E. coli BL21 (DE3) competent cells. However, despite conducting a time course of expression as well as isopropyl β-d-1-thiogalactopyranoside (IPTG) dosage optimization to determine optimal conditions for expression, TccZ protein expression could not be detected on Stain-Free and Coomassie-stained SDS-PAGE gels.

Background. Concurrent coronavirus disease 2019 (COVID-19) and Pneumocystis jirovecii pneumonia (PJP) has been described in various reports, with a recent study describing a 9.3 % P. jirovecii detection rate in critically ill COVID-19 patients.

Methods. Patients with PCR-confirmed PJP following COVID-19 infection who were admitted to Aga Khan University Hospital, Karachi, Pakistan from March 2020–June 2021 were identified through a laboratory database. Detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus was performed by RT-PCR Cobas SARS-CoV-2 qualitative assay. P. jirovecii PCR was performed using the RealStar Pneumocystis jirovecii PCR kit. Clinical, radiological and laboratory data for PJP patients were recorded.

Results. During the study period, 3707 patients were admitted with COVID-19 at our hospital. P. jirovecii PCR was requested for 90 patients and was positive in 10 (11 %). Five out of 10 patients were discharged from the hospital and later developed cough and dyspnoea. Five patients remained hospitalized with severe COVID-19 and developed PJP. Eight patients in our study received systemic steroids. The trends of lymphocyte counts of all patients showed a lymphocyte count of <1000 mm−3 (<1.0×106 cells µl−1) in the week of PJP diagnosis. Four patients did not survive; one of these patients did not receive co-trimoxazole due to late diagnosis, one patient had concomitant nosocomial pneumonia and bacteraemia with multidrug-resistant Acinetobacter species, and two patients had concomitant aspergillosis.

Conclusion. In summary, invasive fungal infections such as PJP should be considered as a complication in COVID-19 patients, with prompt evaluation and management.

Fungal endocarditis is a rare and fatal condition, most frequently caused by species of the genera Candida and Aspergillus. Fever and changing heart murmur are the most common clinical manifestations. The diagnosis of fungal endocarditis is challenging, with prosthetic valve endocarditis being extremely difficult to diagnose. The optimal management of the condition still remains debatable. We present a case of prosthetic valve endocarditis caused by Candida parapsilosis, managed empirically with liposomal amphotericin B, which was later shifted to combination therapy with high-dose echinocandin and fluconazole, but had a fatal outcome because the patient could not undergo timely surgical intervention. Treating C. parapsilosis endocarditis cases is difficult because of their biofilm production on native and prosthetic heart valves. A combined approach consisting of a high index of clinical suspicion, early diagnosis using serological markers followed by culture or PCR and prompt initiation of appropriate antifungals may aid in improving outcomes.