Indian Journal of Microbiology最新文献

Our objective in this study was to develop robust and accurate prediction models for assessing the trends of antimicrobial resistance in China. Data for our study were derived from the China Antimicrobial Resistance Surveillance System, spanning the period from 2014 to 2021. Utilizing these data, we constructed prediction models by GM (1,1), support vector machine, polynomial fitting, and time series. Of all the antibiotics investigated in this study, the resistance rates of carbapenem-resistant Klebsiella pneumoniae and erythromycin-resistant Streptococcus pneumoniae exhibited an upward trend, while resistance rates of the remaining pathogens demonstrated a decreasing trend. The GM (1,1) model demonstrated superior robustness and accuracy among these four models. While a decline in resistance was observed in nine pathogens over time, the antimicrobial-resistant rate of erythromycin-resistant streptococcus pneumoniae and Carbapenems-resistant Pseudomonas aeruginosa was noted to increase, potentially due to the overuse of macrolides in China. These findings underscore the necessity for stricter antibiotic stewardship to counter the risk of widespread resistance. Furthermore, studies from the European Union have reported an escalation in drug resistance relative to pre-pandemic levels, underlining the pandemic's impact on the battle against bacterial resistance.

Supplementary information: The online version contains supplementary material available at 10.1007/s12088-024-01442-z.

Emerging evidence on the role of gut microbiota on human health necessitated the investigations on gut microbial composition and functions. The diet, drug and disease are the major factors that influence the gut microbial composition and subsequent changes in gut physiology. The consequences of external factors on gut microbiota leads to immunological and neurological disorders. The in vivo studies and animal models are associated with difficulties such as surgical procedures, differences in animal and human tissue responses and ethical issues. Microbiota culture outside the in vivo systems provides mechanistic insights on the effect of external factors on gut microbiota function. In order to provide more information on gut microbiota, researchers have developed intestinal gut models that allow the culture of microbiota under controlled conditions. The multistage, dynamic in vitro fermenters have been developed to simulate the stomach, intestine and colon conditions to culture microbiota. The co-culture of host and microbiome is difficult in in vitro models due to differences in the culture media and oxygen requirements for both the cultures. Microfluidics based gut on chip models demonstrated co-culture of host and microbiota in separate channels connected by semipermeable membranes. Host-microbiota interactions play an important role in deciphering the mechanisms of microbiota related human diseases. The ex-vivo systems show more resemblance to the host signaling as these systems use the individual's explants or host tissues. This review discusses the design considerations, pros and cons of the existing in vitro, microfluidic and ex-vivo intestinal microbiota culture models. The collective information provided in this review would be helpful to design novel in vitro microbiota culture models or methods.

Endolichenic fungi (ELF) are gaining attention as a promising source for novel cytotoxic compounds. In this study, lichens Bactrospora myriadea and Arthonia antillarum, collected from the mangroves of Negombo Lagoon in Sri Lanka, were examined to identify their associated ELFs. Phanerochaete chrysosporium, Lasiodiplodia theobromae, and Xylaria feejeensis were isolated from B. myriadea, while Xylaria psidii, Daldinia eschscholtzii, and Nodulisporium sp. were obtained from A. antillarum. The ethyl acetate extracts of these ELFs were screened for cytotoxic activity against the MCF-7 cell line, with P. chrysosporium extract showing potent cytotoxicity. The purified compounds from this extract were identified as spirolaxine (1), phanerosporic acid (2), and 5-(14-hydroxypentadecyl)-resorcinol (3). Their structures were determined using Fourier Transform Infrared, Nuclear Magnetic Resonance spectroscopy and Liquid Chromatography-High Resolution mass spectrometry, while their absolute configurations were established through circular dichroism and time-dependent density functional theory calculations. The compounds demonstrated moderate cytotoxic activity against human breast (MCF-7), oral (CAL-27), and lung (A549) cancer cell lines. Compound 1 exhibited the strongest cytotoxicity against oral cancer, with an IC₅₀ value of 10.62 ± 0.02 µM. Compound 2 was effective against both MCF-7 and A549 cell lines, with IC₅₀ values of 9.86 ± 0.02 µM and 6.66 ± 0.04 µM, respectively. This is the first report of compound 3 from a natural source, as it was previously documented only as a semi-synthetic derivative of compound 2. The study highlights the potential of the ELF P. chrysosporium to produce cytotoxic secondary metabolites.

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Supplementary information: The online version contains supplementary material available at 10.1007/s12088-024-01424-1.

Chicken is a primary source of food worldwide. Ensuring food safety and preserving public health is crucial, and chicken meat inspection plays a critical role in achieving this goal. The transfer of pathogenic bacteria from animal intestines to carcasses during processing, and subsequently from meat products to consumers, is a significant contributor to the growing incidence of resistance and foodborne illnesses. This study aimed to examine the antimicrobial resistance of Staphylococcus aureus present in chicken liver. Fifty samples of chicken liver were collected from various areas of Peshawar and screened for resistant Staphylococcus aureus. The bacteria were tested against different antibiotics, including Moxifloxacin, Vancomycin, Linezolid, Gentamycin, and Clindamycin. Gentamycin demonstrated the highest susceptibility against the maximum bacterial isolates, with 100% susceptibility as its P-value was less than 0.05. Other antibiotics showed effective results. Linezolid was 66.7% susceptible. Both vancomycin and Clindamycin were 41.6% susceptible, while Moxifloxacin was 33.3% susceptible. This study concludes that Staphylococcus aureus isolated from chicken liver has the potential to cause multiple diseases. The screened pathogens were not only resistant to single antibiotics but also showed resistance to multiple antibiotics. The cut-off values of the isolates were two folds higher than those reported in CLSI 2023. The findings highlight the need for effective measures to control the spread of antimicrobial-resistant bacteria and to ensure food safety.

To determine the prevalence, antibiotic susceptibility pattern, and screening for the presence of nuc and mecA genes in staphylococcal isolates collected from a tertiary care hospital in North Karnataka. A total of 250 phenotypically confirmed isolates of Staphylococci were collected from October 2021 to March 2022 from (SDMCMS&H), Dharwad. An Antibiogram of all the isolates was recorded followed by their screening for the presence of mecA gene and nuc gene by Multiplex PCR. Based on the susceptibility to cefoxitin discs and biochemical tests, the isolates were categorized as Methicillin-sensitive S. aureus (MSSA-31/250; 12.4%), Methicillin-resistant S. aureus (MRSA-155/250; 62%), Methicillin sensitive coagulase-negative staphylococci (MSCoNS-3/250; 1.2%) and Methicillin-resistant coagulase-negative staphylococci (MRCoNS-61/250; 24.4%). The isolates exhibited high resistance to penicillin (99.2%), oxacillin (90.3%), cefoxitin (86.4%), levofloxacin (81.6%), ciprofloxacin (80.8%) and erythromycin (76.8%). No vancomycin-resistant staphylococci were detected however 12.6% vancomycin intermediate staphylococci were reported. Susceptibility was highest for daptomycin, and tigecycline (100.0%) followed by teicoplanin (90.7%), and nitrofurantoin (85.5%). Among the 250 staphylococcal isolates, 113/186 (60.75%) of the S. aureus and 17/64 (26.6%) CoNS carried the nuc gene. The prevalence of methicillin resistance was higher in CoNS (95.3%) compared to S. aureus (83.3%). Daptomycin, tigecycline, teicoplanin, vancomycin, and nitrofurantoin are the most effective antibiotics against staphylococcal infections. As compared to a similar study previously carried out at SDMCMS&H Dharwad involving 324 isolates of S. aureus, there is a rise of about 49.7% in the frequency of MRSA since 2008.

Broad industrial application makes cellulolytic enzymes always in industrial demand with economic and sustainable production method. Production of cellulase enzymes via solid state fermentation mode using solid waste can resolve enzyme production and solid waste management issue in eco-friendly way. In present investigation, co-fermentation of solid wastes and microbial co-cultivation using potential cellulase producers strains have been applied as promising strategy for enhancement of cellulase at economical scale. Under the optimized bioprocess, co-fermentative substrate ratio of 5:4 of coconut waste (Ccw) and jamun fruits (JFs) gave 16 IU/gds filter paper (FP) activity at 12 h of incubation via bacillus strains in solid state fermentation (SSF). Additionally, at optimum production temperature of 42 °C and pH 6.0, enzyme showed 19 and 21 IU/gds FP activity at 12 h of incubation. Further, using different organic and inorganic sources, enzyme produced 26 IU/gds FP activity at 12 h peptone as nitrogen source. Additionally, at 60% optimum, moisture content, enzyme gave highest 31 IU/gds FP activity, 239 IU/gds, β-glucosidase (BGL) activity and 176 IU/gds endoglucanase (EG) activity in 12 h of incubation of SSF confirms the efficient production of all cellulolytic components of enzyme. The study has prominent scope in economical industrial application of this enzyme with promising waste management for environment sustainability applications.

Multidrug resistance has become more common in Gram-negative bacteria, making them one of the emerging public health problems with extremely detrimental effects on the world economy. These drugs are broad-spectrum-lactam antibiotics used as a last-resort treatment against multidrug-resistant microorganisms (MDROs). As the resistance to these last-line drugs grows, so does the need to detect and deal with MDROs that carbapenem-resistant. The group B carbapenemases, such as Imipenem metallo-lactamases (IMP) and Verona integron-encoded metallo-lactamases (VIM), are the most prevalent. Integrons, which also include various antibiotic resistance genes, contain the genes for IMP and VIM, promoting their worldwide proliferation. Many papers reported that spreading genes of these enzymes among bacteria rapidly nowadays had had a negative effect on infection control. This review can help with ensuring the understanding of carbapenem resistance as well as policies for eradications and declination of resistance mechanisms that are critical not only for therapeutic treatment but also for infection control measures and epidemic investigations and detections. This review aims to comprehend the mechanism of resistance and transmission of these elements.

'Green' synthesis of nanoparticles from microorganisms and plants is a sustainable alternative to the conventional chemo-physical methods because of its environment-friendliness. Microorganisms take up extracellular and intracellular pathways to manufacture nanoparticles. This study was aimed at optimization of the parameters influencing the biosynthesis of Cu/CuONPs (Copper/Copper oxide nanoparticles) by Pantoea agglomerans CPHN2 using OFAT (One-factor-at-a-time) approach. The optimum biotransformation was achieved at 5 mM concentration of CuSO₄, 32 h incubation time, 6 h reaction time, equal mixing ratio of supernatant and CuSO₄, 7 pH, and 23 °C temperature. Biosynthesized Cu/CuONPs along with those formed chemically, were characterized using UV-Visible spectrophotometer, resulting in a characteristic peak between 550 and 650 nm. Dynamic light scattering (DLS) reported that Z-average and Zeta potential of Cu/CuONPs were 291.9 nm and - 21 mV for biosynthesized and 179 nm and - 6.49 mV for chemosynthesized NPs. HR-TEM (High Resolution-Transmission Electron Microscopy) revealed hexagonal NPs in size range of 5-35 nm. In addition, FTIR (Fourier Transform Infrared) spectrum elucidated different peaks attributed to the Cu/CuONPs, alkynes, O-H, and N-H bonds, of the molecules involved in synthesis and stabilization of biosynthesized NPs. Antimicrobial assay conducted in the presence of 100 µg/ml solution of biosynthesized Cu/CuONPs led to 66.01, 68.31, and 55.73%, inhibition of Staphylococcus aureus growth at 7, 14, and 21 h, respectively, whereas chemosynthesized Cu/CuONPs had negligible impact. The biosynthesized NPs also exhibited 5.48-fold increase in inhibitory activity than chemosynthesized NPs on Bacillus subtilis growth. The results suggests that biosynthesized Cu/CuONPs can serve as ecofriendly and economical method for managing the infections led by gram-positive bacteria.

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Supplementary information: The online version contains supplementary material available at 10.1007/s12088-025-01455-2.

Antimicrobial resistance is gaining a strong foothold in the current healthcare scenario, where skin infections caused by resistant strains of bacteria such as Pseudomonas aeruginosa are unresponsive to a majority of antibiotics. In light of this, there is a pressing need to develop novel strategies to control these pathogens. In this study, we aimed to investigate the antibacterial and antiproliferative activities of the bioactive compounds present in the methanolic extract of Coriandrum sativum seeds. The extract, characterized by GC/MS, exhibited distinct antimicrobial activity (bacteriostatic) against Pseudomonas aeruginosa (ATCC 27853), with a maximum inhibition zone of 30 mm, minimum inhibitory concentration at 1.5625 mg/mL (0.25%) of antimicrobial agent, and decreased cell viability, size, and motility. As Coriandrum sativum is established to cause cell-disruption, we probed the action of the extract on lipopolysaccharide (LPS), a major component in the cell wall, acting as a virulence factor in Pseudomonas aeruginosa (ATCC 27853). Investigations revealed that the extract disrupted LPS, resulting in a significant reduction in LPS-induced inflammation in the A431 epidermoid carcinoma cell line. Additionally, the methanolic extract demonstrated antiproliferative activity, as evidenced by a decrease in cell viability. Our findings provide novel mechanistic insights into the activity of the extract on LPS, and warrant further investigation into its antiproliferative potential.

Supplementary information: The online version contains supplementary material available at 10.1007/s12088-024-01399-z.

Streptococcus equi subsp. equi (S. equi) poses a significant threat to equine health globally. The bacteria causes strangles, a respiratory disease characterized by enlarged, abscessed lymph nodes, leading to airway obstruction. The bacterium, a Gram-positive, chain-forming, Lancefield group C β-hemolytic Streptococcus, is closely related to S. equi subsp. zooepidemicus and distinction between these species is challenging. The present study focused on characterization of S. equi isolates from horses in northern India, aiming at elucidation of their sugar fermentation patterns. Nasal and nasopharyngeal swabs collected from different geographical regions of northern India, yielding S. equi isolates were characterized phenotypically, biochemically and at molecular level. Phenotypic identification revealed typical characteristics of S. equi, including beta-hemolysis on blood agar and majority of them depicted typical mucoid colony characteristic. Biochemical characterization confirmed the identity of the isolates, with most exhibiting fermentation of maltose, lactose, sorbitol and trehalose. PCR analysis targeting the SeM gene provided additional confirmation, displaying a 541 bp product, indicative of S. equi. The study underscores the prevalence of S. equi in equines in India and emphasizes the importance of accurate diagnosis for timely intervention and disease management. The findings contribute to the understanding of S. equi epidemiology and aid in the development of effective control measures to mitigate the impact of strangles outbreaks in the region.

Supplementary information: The online version contains supplementary material available at 10.1007/s12088-024-01420-5.