Crystal Structure of the Catalytic Domain of a Botulinum Neurotoxin Homologue from Enterococcus faecium: Potential Insights into Substrate Recognition.

Clostridium botulinum neurotoxins (BoNTs) are the most potent toxins known, causing the deadly disease botulism. They function through Zn2+-dependent endopeptidase cleavage of SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) proteins, preventing vesicular fusion and subsequent neurotransmitter release from motor neurons. Several serotypes of BoNTs produced by Clostridium botulinum (BoNT/A-/G and/X) have been well-characterised over the years. However, a BoNT-like gene (homologue of BoNT) was recently identified in the non-clostridial species, Enterococcus faecium, which is the leading cause of hospital-acquired multi-drug resistant infections. Here, we report the crystal structure of the catalytic domain of a BoNT homologue from Enterococcus faecium (LC/En) at 2.0 Å resolution. Detailed structural analysis in comparison with the full-length BoNT/En AlphaFold2-predicted structure, LC/A (from BoNT/A), and LC/F (from BoNT/F) revealed putative subsites and exosites (including loops 1-5) involved in recognition of LC/En substrates. LC/En also appears to possess a conserved autoproteolytic cleavage site whose function is yet to be established.

Prevalence of multi-drug resistant Pseudomonas aeruginosa isolated from selected residential sewages in Dutsin-Ma, Katsina State, Nigeria.

The global surge in Multidrug resistant (MDR) bacteria is an issue of great concern. Pseudomonas aeruginosa has been implicated in several nosocomial infections, where it has caused grave complications in immunocompromised patients. This is the first study to report the prevalence of MDR P. aeruginosa isolated from residential sewage in Dutsin-Ma, Katsina State, Nigeria. Pseudomonads count, isolation, biochemical characterization and antibiogram were carried out using standard microbiological procedures. This study examined sixty (60) samples from selected residential sewage in the study site collected at different intervals between July and September 2021. A total of 40 (66.7%) P. aeruginosa were isolated from the analyzed sewage samples. The highest (2.84x104) pseudomonad count was recorded from sewage samples collected from Kadangaru. Pseudomonas aeruginosa isolates from this sample site showed the highest (100%) resistance to cephalosporins (cefuroxime) and nitrofurantoin. Similarly, isolates from Miami area also demonstrated the highest (95%) resistance to a cephalosporin (ceftazidime). All (100%) isolates used in this study showed MDR resistance to tested antibiotics. The occurrence of MDR P. aeruginosa from a residential sewage site that may contaminate drinking water sources in the study area is of public health threat to the inhabitants. Surveillance and molecular epidemiology of antibiotics resistant bacteria are urgently needed in the study area.

Bacteriological qualities and antibiogram studies of bacteria from "suya" and smoked fish (Clarias gariepinus) in Dutsin-Ma, Katsina State, Nigeria.

INTRODUCTION: "suya" and smoked fish are cherished food delicacies in Nigeria, but can be a source of dissemination of Multi-drug Resistant (MDR) bacteria. Moreover, there are limited studies on these MDR bacteria from Dutsin-Ma. Therefore, this study examined the bacteriological qualities and antibiogram profiles of bacteria in these foods from this area in Nigeria. METHODS: Twenty samples of each of "suya" and smoked fish were collected from the study areas and microbiologically analyzed. Total viable count, coliform count, characterization and identification of bacteria were carried out by standard microbiological techniques. RESULTS: Findings revealed that "suya" samples possessed the highest total viable bacteria count (3.4×105 to 7.7×105 cfu/g) and coliform count (2.1×105 to 6.2×105 cfu/g). A total of 85 and 78 bacteria were isolated from "suya" and smoked fish samples respectively. E. coli (24.7% and 24.4%) was the most frequently isolated from each sample respectively. Highest (66.7%) resistance to each of cefuroxime, gentamicin, amoxillin/clavulanate and ciprofloxacin were observed among E. coli from "suya". MDR phenotypes commonly isolated was resistance to ceftazidime, cefuroxime, ampicillin, ciprofloxacin, augmentin and nitrofurantoin. CONCLUSION: These studies showed the presence of MDR bacteria in samples, hence, raise the need for improved production hygiene and public health awareness.

Prevalence of multi-drug resistant Pseudomonas aeruginosa isolated from selected residential sewages in Dutsin-Ma, Katsina State, Nigeria

The global surge in Multidrug resistant (MDR) bacteria is an issue of great concern. Pseudomonas aeruginosa has been implicated in several nosocomial infections, where it has caused grave complications in immunocompromised patients. This is the first study to report the prevalence of MDR P. aeruginosa isolated from residential sewage in Dutsin-Ma, Katsina State, Nigeria. Pseudomonads count, isolation, biochemical characterization and antibiogram were carried out using standard microbiological procedures. This study examined sixty (60) samples from selected residential sewage in the study site collected at different intervals between July and September 2021. A total of 40 (66.7%) P. aeruginosa were isolated from the analyzed sewage samples. The highest (2.84x104) pseudomonad count was recorded from sewage samples collected from Kadangaru. Pseudomonas aeruginosa isolates from this sample site showed the highest (100%) resistance to cephalosporins (cefuroxime) and nitrofurantoin. Similarly, isolates from Miami area also demonstrated the highest (95%) resistance to a cephalosporin (ceftazidime). All (100%) isolates used in this study showed MDR resistance to tested antibiotics. The occurrence of MDR P. aeruginosa from a residential sewage site that may contaminate drinking water sources in the study area is of public health threat to the inhabitants. Surveillance and molecular epidemiology of antibiotics resistant bacteria are urgently needed in the study area.