Antibiotic Resistance Pattern and Biochemical Characterisation of an Extended-Spectrum β-Lactamase in an Intensive Care Unit | Chapter 6 | Microbiology and Biotechnology Research: An Overview Vol. 5

 

β-Lactamases production by bacteria remains the most important mechanism of natural and acquired resistance to β-lactams, particularly in Gram-negative bacteria. Over time, these β-enzymes have evolved in parallel with the massive use of β-lactams. Thus, we have witnessed the emergence and rapid diversification of new enzymes accompanied by broadening of their spectrum of activity and their diffusion among bacteria. Gram-negative bacteria producing beta-lactamase are of significant concern, particularly due to their prevalence in nosocomial infections. Remarkably, Enterobacter cloacae (E. cloacae) is recognised as a nosocomial pathogen that causes significant infections in hospitals, especially in recent years. During the nosocomial infections occurring in the intensive care unit of the military hospital of Tunis, the Enterobacter cloacae strain was isolated from a stool culture. This strain was found to have a high level of resistance to broad-spectrum β-lactams. The antibiotic susceptibility of the E. cloacae strain was determined on Mueller-Hinton agar by the standard disk diffusion procedure. Resistance profile against the various families of antibiotics was determined using the disc diffusion test. The minimal inhibitory concentration values showed that this strain was resistant to the β-lactams such as ampicillin and the extended spectrum cephalosporins (cefotaxime, ceftriaxon and cefpirome). Analysis of this strain by the disk diffusion test revealed synergies between amoxicillin-clavulanate (AMX-CA) and ceftriaxon, ceftazidime and cefotaxime. Cell sonicate of this isolate is very active against cefotaxime and showed a specific activity (AS) of 7.54 U/mg for the same antibiotic. This activity was inhibited by the sulbactam and the clavulanic acid. Isoelectrofocusing methods revealed that the crude extract of the E. cloacae strain showed 1 β- β-lactamase activity with an isoelectric point (pI) of about 8. This activity was transferred by conjugation and was highly expressed in the transconjugant. These findings provide an evaluation of the biochemical characteristics of a cefotaxime-hydrolysing β-lactamase encoded by a conjugative plasmid in Enterobacter cloacae, emphasising the need for continuous surveillance in a hospital setting.

 

 

Author(s) Details

Bourouis Amel
Laboratoire de Biochimie et Biotechnologie LR01ES05, Faculté des Sciences de Tunis, Université de Tunis El Manar, 2092 El Manar II, Tunisie.

 

Chihi Hela
Laboratoire de Biochimie et Biotechnologie LR01ES05, Faculté des Sciences de Tunis, Université de Tunis El Manar, 2092 El Manar II, Tunisie.

 

Ben-Achour Nehed
Laboratoire de Biochimie et Biotechnologie LR01ES05, Faculté des Sciences de Tunis, Université de Tunis El Manar, 2092 El Manar II, Tunisie.

 

Bargellil Farouk
Service de Bactériologie, Hôpital Militaire de Tunis, 1089 Monfleury, Tunisie.

 

Naghmouchi Karim
Laboratoire de Biochimie et Biotechnologie LR01ES05, Faculté des Sciences de Tunis, Université de Tunis El Manar, 2092 El Manar II, Tunisie.

 

Ben-Mehrez Kamel
Laboratoire de Biochimie et Biotechnologie LR01ES05, Faculté des Sciences de Tunis, Université de Tunis El Manar, 2092 El Manar II, Tunisie.

 

 

Please see the book here :- https://doi.org/10.9734/bpi/mbrao/v5/5516

Enhancing Drought Tolerance in Sorghum Plants through Bacterial Inoculation: A Study on Water Retention and Stomatal Conductance | Chapter 8 | Research Advances in Microbiology and Biotechnology Vol. 9

 The study evaluates the impact of moisture stress tolerant bacterial inoculants on the relative water content and stomatal conductance of sorghum leaves under drought conditions. Drought is one of the major abiotic stresses that adversely affects majority of the world’s crop growth and productivity. The relative water content (RWC) and stomatal conductance (SC) in sorghum (Sorghum bicolor, L.) leaves were assessed under water stress condition by sorghum seed priming with Serratia marcescens strain L1SC8, Pseudomonas putida strain L3SC1, Enterobacter cloacae strain L1CcC1 and Serratia marcescens strain L2FmA4. RWC was higher in leaves of seed priming plants. Water stress resulted in decreased RWC of plant leaves. Seed priming with Serratia marcescens strain L1SC8 showed higher RWC over untreated control followed by Enterobacter cloacae strain L1CcC1. However SC decreased in seed primed stressed plants leaves compared to non-primed stressed plant leaves. Pseudomonas putida strain L3SC1 showed lowest SC as compared to other treatments and control. All the bacterial inoculant increases the RWC. The increase in RWC was statistically significant over control. Thus, the moisture stress tolerant bacterial inoculants sustain the drought condition by increasing the RWC in plant. Thus, seed priming with moisture stress tolerant bacterial cultures increase the RWC while decrease the SC which was the major attributing factors for drought tolerance in sorghum. The findings provide valuable insights into potential strategies for enhancing drought tolerance in crop plants, with implications for agricultural productivity in water- stressed environments. Additionally, the study contributes to the understanding of the role of microbial inoculation in inducing physiological changes in plants to cope with water stress, which is a topic of increasing interest in agricultural research.

Author(s) Details:

Kalindee S. Shinde,
Department of Plant Pathology and Agricultural Microbiology, Mahatma Phule Krishi Vidyapeeth, Rahuri-413722, Maharashtra, India.

Please see the link here: https://stm.bookpi.org/RAMB/article/view/13227

Determination of Antibacterial Effects of Fenugreek, Wheat and Hot Red Pepper Seeds and Their Germs Extract on Inhibiting Staphylococcus aureus and Enterobacter Cloacae Growth | Chapter 8 | Innovations in Microbiology and Biotechnology Vol. 2

 Aims: This study looked into the effects of plant seeds like fenugreek (Trigonella foenum-graecum L.), wheat grains (Triticum aestivum L.), and hot red pepper (Capsicum annuum L.), which have traditionally been used as natural food preservatives or at least to reduce the use of artificial preservatives, while also acting as antibacterial agents against certain positive and negative gramme bacteria like Staphylococcus

The tests were set up in a one-way, entirely randomised fashion.

The trials took place at the Regional Center for Food and Feed (RCFF), the Agricultural Research Center, and the Faculty of Agriculture Saba Basha at Alexandria University in Egypt.

The total live bacterial counts were obtained using the plate count agar method after 5 days of incubation at 25°C to estimate the living bacterial cells in each treatment. Microbial counts were evaluated in all samples using serial dilutions, as well as total flavonoids, antioxidant activity, and total phenol content of the analysed seeds and germs.

The maximum number of S. aureus bacteria in 10-1 on wheat germinated seeds extract at 1000 l was 290 CFU, while the maximum number of E. cloaceae bacteria was 370 CFU in wheat non-germinated seeds at 500 l concentration. However, the highly inhibitory concentration of S. aureus 1000 l was achieved using non-germinated red pepper seeds extract (97.9%) and (92.9 percent) in the case of E. cloaceae bacteria. Under the concentration 1000 l, the maximum inhibitory percentage was determined with red pepper non-germinated seeds for (S. aureus) was (97.9%) and for (E. cloaceae) was (92.9%). Germ extract was found to be less effective as an antibacterial agent than seed extract. E. cloacae was more resistant than S. aureus. The use of hot red pepper seed extracts, followed by fenugreek extract, was extremely successful in inhibiting the development of both bacteria examined.

Conclusion: The multiplication of several harmful bacterial strains is a common cause of food spoiling. Chemical preservatives are used extensively in the food business and on food products to avoid rotting. Extracts of hot pepper and fenugreek can be used as natural alternatives to avoid food poisoning. Non-germinated seeds are the most effective against the microorganisms that have been studied.

Author(S) Details

Nesrine H. Youssef
Regional Center for Food and Feed (RCFF), Agricultural Research Center, Dekhila Port, Alexandria, Egypt.

Mayada A. Sabra
Agriculture Botany Department, Faculty of Agriculture Saba Basha, Alexandria University, Egypt.

View Book:- https://stm.bookpi.org/IMB-V2/article/view/4720