Salmonella is one of the most common causes of foodborne diseases among humans worldwide. Animal-derived foods are frequently tested for the presence of Salmonella spp. However, the detection of Salmonella in meat and its products is often hindered due to the presence of background normal flora, which may lead to the detection of false-positive Salmonella. The present study aimed to isolate and accurately identify Salmonella spp. from poultry meat. For this purpose, seventy poultry meat samples were collected from Lahore, Pakistan, isolated on selective and differential media, and identified using biochemical tests and polymerase chain reaction for the 16S rRNA gene of identified strains. The results of selective and differential media culturing and biochemical tests were compared with the results of 16S rRNA gene sequencing. It was inferred that the phenylalanine deaminase test and triple sugar iron tests eliminate the false-positive Salmonella isolates obtained on isolation media, and along with the PCR technique, can serve as an accurate and efficient method for the correct detection of Salmonella spp. from meat samples. In order to reduce the false-positive Salmonella isolates, a highly specific selective media must be designed which can distinguish Salmonella forming different colors of colonies from other bacteria and also cause the inhibition of non-Salmonellaisolates.

Cave actinobacteria are relatively less explored and are considered as the new targets for the discovery of novel antimicrobials, specifically against highly resistant pathogens such as extensively drug-resistant (XDR) Salmonella. In this study N=20 actinobacteria isolates were retrieved from the least disturbed caves situated at Bahadurkhel Karak, Pakistan (33° 16’ 52” North, 70° 79’ 07” East) and (33° 15’ 90” North, 70° 94’ 72” East). The isolates were identified using standard morphological and biochemical characterization procedures as well as by 16S rDNA sequencing. N= 16 isolates were targeted for further antimicrobial activity screening based on their preliminary morphological and biochemical identification. The methanolic extracts were prepared from the culture broth of the isolates by using Amberlite® XAD-16 resin to execute in situ solid phase extraction. The thin layer chromatography (TLC) showed the presence of a variety of different compounds in the crude extracts of the secondary metabolites. The extracts’ antimicrobial potential was analyzed against several test strains, including Salmonella enterica, Staphylococcus aureus, Bacillus subtilis, Klebsiella pneumoniae, and Escherichia coli. Among the isolated strains, the isolates SNK 93 and SNK47 were found to be the most active against the tested pathogenic bacteria, showing growth inhibition zones of 20 mm and 27 mm respectively against extensively drug-resistant (XDR) Salmonella. Based on these results it can be concluded that cave actinobacteria are a promising source of potentially novel antimicrobials against multidrug-resistant (MDR) and XDR pathogens.

Since the advent of the COVID-19 pandemic in 2019, a mammoth research activity targeting the etiological features of COVID-19 has commenced. Many aspects of the disease have been studied, and various others are under consideration. The secondary microbial co-infections with COVID-19 have generated some serious concerns across the globe. This review mainly focuses on the notable secondary co-infections. The co-infection of influenza, tuberculosis, and typhoid may mimic the original COVID-19 symptoms. Physicians and clinicians must focus on the secondary co-infections which may aggravate the disease progression towards acute respiratory disorder syndrome (ARDS). Diagnostic strategies must also be redefined to determine the actual underlying secondary co-infection. There is a need for combination therapy and diagnostic approaches to minimize the risks associated with the COVID-19 pandemic effectively.

Background Bioprospecting of actinobacteria isolated from Kubuqi desert, China for antibacterial, antifungal and cytotoxic metabolites production and their structure elucidation. Results A total of 100 actinobacteria strains were selectively isolated from Kubuqi desert, Inner Mongolia, China. The taxonomic characterization revealed Streptomyces as the predominant genus comprising 37 different species, along with the rare actinobacterial genus Lentzea. The methanolic extracts of 60.8% of strains exhibited potent antimicrobial activities against Staphylococcus aureus, Micrococcus luteus, Bacillus subtilis, Escherichia coli, Salmonella enterica, Saccharomyces cerevisiae and high to mild in vitro cytotoxicity against PC3 (prostate cancer) and A549 (lung carcinoma) cell lines. The metabolomics analysis by TLC, HPLC-UV/vis, HPLC-MS and NMR showed the presence of compounds with molecular weights ranging from 100 to 1000 Da. The scale-up fermentation of the prioritized anti-Gram-negative strain PU-KB10–4 (Streptomyces griseoviridis), yielded three pure compounds including; griseoviridin (1; 42.0 mgL− 1) with 20 fold increased production as compared to previous reports and its crystal structure as monohydrate form is herein reported for the first time, mitomycin C (2; 0.3 mgL− 1) and a new bacterial metabolite 4-hydroxycinnamide (3; 0.59 mgL− 1). Conclusions This is the first report of the bioprospecting and exploration of actinobacteria from Kubuqi desert and the metabolite 4-hydroxycinnamide (3) is first time isolated from a bacterial source. This study demonstrated that actinobacteria from Kubuqi desert are a potential source of novel bioactive natural products. Underexplored harsh environments like the Kubuqi desert may harbor a wider diversity of actinobacteria, particularly Streptomyces, which produce unique metabolites and are an intriguing source to develop medicinally valuable natural products.