Research Perspectives of Microbiology and Biotechnology Vol. 5

Food contaminated with bacterial pathogens is still a problem worldwide.  Campylobacter jejuni causes over 99% of the foodborne infections associated with Campylobacter in the United States. This study involves the evaluation of commercially available plant extracts of oregano, green tea, hawthorn, and curcumin against four isolates of C. jejuni.  In this study, four different strains of C. jejuni were used: one human strain (81176) and three poultry strains isolated from different stages of poultry processing including a pre-chilled chicken carcass (PRCC), a post-chilled chicken carcass (POCC) and a retail chicken carcass (RECC).  Initial studies were first carried out in broth cultures to determine the general effectiveness of the extracts.  The study then was carried out on chicken breast meat to determine the effect of the plant extracts in marinades.  Cell counts were determined at intervals of 0, 2, 6 and 24 hours and bacterial viability was determined using different concentrations of the above extracts.  Both oregano and green tea extracts were found to be antibacterial even at low concentrations in broth cultures and killed all bacteria in 24 hours. But as marinades on chicken breast meat, the extracts were found to be effective only at higher concentrations.  No significant differences were found in the antibacterial effects of the extracts on different C. jejuni strains.  These results demonstrate that commercially available plant extracts such as oregano and green tea have the potential to reduce and/or eliminate C. jejuni in chicken meat. Combinations of plant extracts have to be explored to resolve the problem of the high concentration required to inhibit C. jejuni strains in meat.

This book chapter presents a comprehensive update on the diverse species of Viridans Streptococci implicated in the pathogenesis of infective endocarditis (IE). It explores recent insights into the epidemiology, pathogenic mechanisms, clinical manifestations, diagnostic approaches, and therapeutic considerations specific to Viridans streptococci-associated IE. The chapter highlights advancements in understanding the genetic variability, antimicrobial resistance profiles, and virulence determinants of these bacterial species, underscoring their clinical significance and implications for patient management. Additionally, emerging trends and challenges in the diagnosis and treatment of IE caused by Viridans streptococci are discussed, offering valuable perspectives for future research and clinical practice [1].

The world's deltas are home to a vast array of distinct soil and aquatic microbes, most of which take the form of bacteria, fungi, parasites, archaeans, actinomycetes, viruses, etc. They support the ecosystem in many ways, helping to preserve the equilibrium of the natural elements, the biogeological components, and the ecological components. In addition to offering plants environmental and natural defense against pests and diseases, soil microbes also help plants thrive. They play a critical role in converting nutrients and nitrogen into forms that plants can eat. The various functions that aquatic and soil bacteria play are decomposition, oxygen production, evolution, and symbiosis. Certain River Deltas have the highest concentrations of the saline soil-dependent bacterial and fungal community, whereas other River Deltas are enhanced with certain microbes that aid in soil remediation. In certain instances, variations in the C, N, and P ratios are caused by specific kinds of bacteria that break down hydrocarbons. Given that bacteria also produce various allergens and antigens, which are the primary causes of a variety of infectious diseases, some bacteria are used in research studies to produce anti-allergens and medicinal drugs.

Hepatitis delta virus (HDV) was discovered in 1977 by Italian gastroenterologist Mario Rizzetto. The small and large delta antigens (S-HDAg and L-HDAg, respectively) represent two forms of the only protein encoded by the hepatitis Delta virus (HDV) RNA genome. Consequently, HDV relies, to a large extent, on the host cell machinery for replication and transcription. Using different approaches few cellular proteins were identified as S- HDAg or L-HDAg partners with limited evidence of their involvement in the modulation of the virus life cycle and mechanisms of pathogenesis. Here we performed a yeast two-hybrid screening of a human liver cDNA library to identify cellular proteins that bind to S-HDAg. We were able to identify HuR, a ubiquitously expressed protein involved in the regulation of gene expression at the posttranscriptional level, and associated with cancer, as an S-HDAg partner both in vitro and in vivo. HuR was found to be overexpressed and colocalized with HDAg in human hepatoma cells. siRNA knockdown of HuR mRNA resulted in inhibition of S-HDAg and L-HDAg expression. The obtained results suggest that HuR may play an important role in the HDV replication cycle and pathogenesis.

Introduction: Urinary tract infections can affect all individuals, regardless of gender and age, occupying a prominent place in nephrological pathology. The major issue is that pathology with a wide range of antibiotics and other hygiene measures that can remedy it remains so frequent with sometimes serious complications that can compromise the vital prognosis. Extended-spectrum \(\beta\)-lactamases (ESBLs) are a group of diverse, complex, and rapidly evolving plasmid-mediated enzymes that today pose a major therapeutic challenge in the treatment of hospitalized and community patients.

Objectives: The primary objective of this study is to determine the antibiogram profile of enterobacteria in urinary infections. This study assesses the beta-lactam resistance and detects extended-spectrum beta-lactamase in Enterobacteriaceae isolated from community-acquired urinary tract infections.

Methodology: This is a cross-sectional study with an analytical aim of enterobacteria isolated from urinary infections from samples from patients of all ages from January 1, 2020, to October 21, 2022. Antimicrobial susceptibility testing for all enterobacteria was done using the Kirby-Bauer disk diffusion method according to Clinical Laboratory Standard Institute (CLSI) guidelines.

Results: The isolated enterobacteria strains presented high rates of resistance, i.e. 92.61% for Ampicillin, 47.94% for cefadroxil, 45.14% for cefuroxime, and 46.46% for cefotaxime, 72.86% for amoxicillin and 40.44% for amoxicillin + clavulanic acid. Qualitative detection of extended-spectrum Beta-Lactamase was generally evaluated at 24.8% with peaks for Citrobacter sp., Klebsiella sp., and E coli. For the latter, cross-resistance to quinolones was evaluated in proportions ranging from 49.45% to 85.51%.

Conclusion: This situation poses a significant public health challenge and highlights the urgent need to improve sanitation and implement antibiotic stewardship in developing countries. This study shows that the level of resistance of enterobacteria to beta-lactams is very high. We have observed co-resistance between beta-lactams and quinolones, antibiotics commonly used against Gram-negative bacteria. This observation requires an improvement in the antibiotic management policy.

Antimicrobial resistance is a matter of great concern due to the reduced efficacy or failures of antibiotics to treat various bacterial infections. At present, there are few reports available on the isolation and prevalence of antibiotic resistance genes on E. coli found in wild captive animal species. Therefore, the present study was conducted to investigate the phenotypic and genotypic properties of E. coli isolates obtained from wild captive animals at Bikaner Zoo in regard to their antibiotic resistance. In the present study, a total of 41 E. coli isolates obtained from Boselaphus tragocamelus (5), Antelope cervicapra (18) and Gazella gazelle (18) maintained at Bikaner Zoo (Rajasthan) were subjected to antibiogram determination against 15 antibiotics belonging to four different classes and were also genotyped for detecting presence of bla_TEM, sul-2, strA and aadA genes. Antimicrobial susceptibility was performed by the agar disc diffusion method. The polymerase chain reaction was carried out with a Veriti 96 well thermocycler to detect the presence of the identified genes amplified through specific primers. Antibiogram study revealed the highest efficacy of ciprofloxacin (90.2%) followed by nalidixic acid (75.6%) and chloramphenicol (68.4%) and high resistance to \(\beta\) lactam, Sulfamethoxazole and Aminoglycoside antibiotics. The overall presence of bla_TEM, sul-2, strA and aadA genes was detected in 95.12%, 80.48%, 60.97% and 87.8% in isolates. This study's findings reveal that wild captive animals may act as a reservoir of antibiotic resistant genes which may be mobilized into other ecological populations. The data from the present study accounts for the critical need for regulation of antimicrobial drug usage in wild captive animals and highlights for continuous monitoring of antibiotic resistance.

Determining the frequency of parasitic agents within the human population in a particular region is important for the development of preventive interventions and treatment strategies. This study, aimed to determine the 5-year prevalence of intestinal parasites in patients admitted to the Microbiology laboratory of a tertiary hospital in Somalia. Intestinal parasites; Types of patients, age and sex of the patients, and the distribution by years were studied. Fecal samples were collected in fecal containers. Stool samples were examined using wet preparation, native lugol and trichrome staining methods. Statistical analysis was performed using IBM SPSS V23 software and a P value of <0.05 was considered statistically significant. One or more parasites were detected in 6766 of 56,824 stool samples examined. It was observed that Giardia lamblia had a higher prevalence than other parasites (60.84%) in a five-year period. Entamoeba histolytica (33.07%) was in second rank and Ascaris lumbricoides (3.18%) was in third rank according to their prevalence. When the distribution of the parasite population by gender was evaluated; no statistically significant difference was found (p = 0.235). When the frequency of parasites was evaluated according to age groups, it was seen that the prevalence of parasites between the ages of 0–15 was higher (45.5%) compared to other age groups. A statistically significant difference was found between the distribution of parasite groups according to age groups (p < 0.001). The fact that the parasite rate we found in our study was 11.9% showed that parasitic diseases continue to be an important health problem that needs to be combated in our region. Developing effective treatment protocols is as important as taking preventive measures to combat infectious diseases caused by parasites.

An experiment was conducted to examine the rumen microbial degradation of whole cottonseed (WCS) compared to other tropical oilseeds in a consecutive batch culture (CBC) system. The selection of oilseeds was mustard seed (cv. Albatross), linseed (cv. Antares) and three cultivars of rape seeds namely cv. Bienvenu, cv. Libravo and cv. Samourai. The CBC system was established according to the methods of Theodorou [1]. The results of this experiment indicated that the mean dry matter (DM) losses, gas production, and total volatile fatty acids (VFA) of WCS were significantly lower than those of other oilseeds. In contrast, mustard seed had the highest DM losses indicating that mustard seed was more readily fermentable to rumen microbes than other oilseeds. Rumen microbes appeared to adapt to the presence of oilseeds. WCS consistently had lower DM losses, gas production, and total VFA. It was concluded that the lower microbial degradation and fermentation of WCS was probably due to gossypol, tannin, and other factors such as lignin, fat, and the physical structure of fibre in WCS.

The increase of multidrug-resistant bacteria, Staphylococcus aureus (SA) and methicillin-resistant Staphylococcus aureus (MRSA) is an alarming problem for global health in recent years and in the near future. To solve this problem, finding new antibiotics is one of the top priorities. In the structure of MRSA bacteria, penicillin-binding proteins (PBPs) play a role in the integrity of the bacterial cell wall and prevent the entry of harmful molecules into the bacteria. Hence, PBPs are the key factors in the mechanism of antibiotic resistance activity of MRSA. Developing therapies for MRSA-associated infections through compounds that directly act on PBPs is a recent promising approach. To achieve this goal, researchers are going to combine in silico, in vitro, and in vivo experiments to screen and elucidate the mechanism by which natural compounds from herbal plants or compounds in compound libraries such as alkaloids and flavonoids, promising antibiotics agents to inhibit MRSA, target PBPs. This review will introduce the structure properties and pathogen characteristics of SA and MRSA and some promising candidates from herbal medicine and commercial compounds with potential antimicrobial properties against SA and MRSA through interaction with housekeeping genes of PBPs. The information from this study will provide important scientific evidence in the evolution of S. aureus to become MRSA and the potential inhibitors against MRSA, which are innovative approaches to combat antibiotic-resistant Staphylococci in the future.

Aims: Indigenous fermented milk products like mishtidoi, shrikhand, lassi and buttermilk that are famous products of West Bengal, Maharashtra, Punjab, and Karnataka, respectively. Nowadays, they are available all over India and are liked by the majority of the human population. These are fermented products acidic in nature, contain sugar that favours the growth of molds and thus require refrigeration to increase the shelf life. Prolonged storage of these products may provide good growth conditions for psychrotrophic molds which grow at lower temperatures. This may lead to the deterioration of products by the proteinases and lipases produced by molds and few of the psychrotrophic molds excrete mycotoxins making the product unsafe for consumption. With this background, the present study was taken up to find the types of psychrotrophic molds in Indigenous fermented milk products available in the Bengaluru market as well as to characterize their nature.

Study Design: In order to study the types of psychrotrophic molds present in indigenous fermented milk products, unbranded (n=6) and branded (n=15) samples such as mishtidoi, shrikhand, lassi and buttermilk were collected from Bangalore markets and subjected to isolation of molds at low temperature (0-7⁰C) using selective medium and further the isolates obtained were identified based on their characteristics.

Place and Duration of Study: The research work was conducted in the Department of Dairy Microbiology, Dairy Science College, Karnataka Veterinary, Animal and Fisheries Sciences University (KVAFSU), Hebbal, Bengaluru, 560 024, Karnataka, India between June 2014 to June 2015 as part of postgraduate research work, Hebbal, Bangalore-24 and literature was updated recently.

Methodology: The market samples of indigenous fermented dairy product samples were subjected to pour plating using sterile malt extract agar adjusted to pH 3.5 and incubated plates at 5^oC for 25 days. The mold isolates obtained were identified by colony morphology, microscopic examination for cell morphology and specific biochemical tests.

Results: A total of 21 psychrotrophic mold isolates were obtained from branded and unbranded indigenous fermented milk products. Among 21 psychrotrophic molds, 6 and 15 isolates were obtained from unbranded and branded samples, respectively. Based on the preliminary identification, the isolates were characterized as Penicillium spp., (n=3), Mucor spp., (n=2) and Cladosporium spp., (n=1) from unbranded samples while branded indigenous fermented dairy product samples showed Penicillium spp., (n=9) and Alternaria spp., (n=6) were isolated from branded samples. According to pheno and genotypic characterization, the isolates were identified as Penicillium chrysogenum (57.12%), Alternaria alternata (28.56%), Mucor mehei (9.52%) and Cladosporium cladosporioides (4.76%) at the species level. Except for unbranded mishitdoi, all types of indigenous fermented dairy product samples were found to contain psychrotrophic molds.

Conclusion: Penicillium chrysogenum was the most abundant species found especially in branded butter milk indicating longer refrigeration may lead to the selection of psychrotrophic molds due to low-temperature storage and favourable pH (3-5) of the indigenous fermented dairy product samples. This psychrotrophic mold produced citrinin, a mycotoxin that affects the liver. Hence care must be taken to avoid consumption of long-stored refrigerated indigenous fermented products like lassi and buttermilk.