PREVALENCE AND MOLECULAR CHARACTERIZATION OF EXTENDED SPECTRUM β-LACTAMASES IN KLEBSIELLA PNEUMONIAE ISOLATES FROM CANCER PATIENTS AND OTHERS

Objective: Klebsiella pneumoniae is highly prevalent in hospitals and causes many nosocomial infections. The study sought to determine prevalence rates of extended spectrum β-lactamases (ESBLs) in clinical isolates of K. pneumoniae from Cairo, Egypt and to detect the ESBL-encoding genes in the isolates.Methods: K. pneumoniae isolates were collected through two-year period (2011-2012). Identification of K. pneumoniae was carried out using automated Microscan and standard biochemical tests. ESBL pattern and minimum inhibitory concentrations (MICs) were detected using Clinical and Laboratory Standards Institute guidelines and confirmatory tests. Multiplex polymerase chain reaction for ESBL-encoding genes and plasmid profiling were performed.Results: In the present work; 112 isolates, 75 of them from cancer patients, were characterized. High proportion (52 of 112, 46 %â€) of ESBLs among the isolates were detected. Highest prevalence of ESBLs was seen among cancer patients, 39 isolates of 75 (52%). Plasmid profile for ESBL-producing K. pneumoniae isolates showed different sizes and numbers of plasmids in all isolates. MICs for all ESBL-producing isolates revealed high resistance rates with tetracycline (100%), cefepime (96%), gentamycin (90%) and ciprofloxacin (79%). Whereas, only two isolates (4%) were resistant to both carbapenem drugs tested, imipenem and meropenem. blaTEM, blaSHV, and bla CTX-M were performed for all ESBL-producing isolates. Five patterns of ESBL-encoding genes were detected. The most prevalent ESBL-encoding gene was blaTEM;alone in 40% and with other ESBL-encoding gene(s) in 48% of the isolates.Conclusion: High prevalence of ESBL (46%) in our isolates suggesting the need for continuous monitoring of emergence of this pattern in our region.Â

Endoscopic retrograde cholangiopancreatography versus conservative treatment for patients with symptomatic small common bile duct stones: A randomized controlled trial

Background: Endoscopic retrograde cholangiopancreatography (ERCP) is the recommended treatment for common bile duct stones (CBDS). However, CBDS, tiny ones, can spontaneously pass through the ampulla of Vater, reducing unnecessary ERCP and its related significant complications. Objectives: This study compared endoscopic stone extraction versus conservative treatment for managing symptomatic small CBDS. Patients and methods: This randomized controlled trial included 168 patients with symptomatic CBDS (≤ 7 mm) and gallbladder stones. Of these, 85 patients underwent endoscopic stone extraction, and 83 patients underwent conservative treatment for the CBDS, followed by laparoscopic cholecystectomy and intraoperative cholangiography between June 2019 and March 2023. The primary outcome was the overall success rate, while useless procedures, morbidity, mortality, length of hospital stay, total cost, and recurrent biliary symptoms were considered secondary outcomes. Results: Our study showed that the ERCP group had a significantly higher overall success rate (96.5% vs. 22.9%, P < 0.001), fewer useless procedures (14.1% vs. 77.1%, P < 0.001), a shorter median hospital stay (5 vs. 8 days, P < 0.001), and reduced total costs (1810 vs. 2250 US$, P < 0.001). Both groups had no significant difference in morbidity or recurrent biliary symptoms (2.4% vs. 7.2%, P = 0.14). There was no mortality rate in both groups. Conclusion: Symptomatic small CBDS should be managed surgically as early as possible. Endoscopic stone extraction has a significantly high success rate, a shorter hospital stay, and a lower total cost. The conservative treatment for symptomatic small CBDS is useless and should not be practiced

Cloning and expression of recombinant hyaluronidase enzyme from Staphylococcus aureus using Escherichia coli

282-291Hyaluronidase (HysA) is an important microbial enzyme that has medical importance. Hyaluronidase enzyme is produced by Staphylococcus aureus and is responsible for the spread of the organism during infection. A total of 85 clinical isolates of S. aureus were examined for hyaluronidase production. Strain of S. aureus S10 was associated with the highest productivity of hysA enzyme among the investigated isolates. The hysA gene was amplified from isolate S10 and S. aureus Newman by PCR method and cloned into the expression vector pRSET-B. The protein expression of the cloned hysA of S. aureus Newman (HysA-New protein) and S. aureus S10 (HysA-S10 protein) was performed in Escherichia coli BL21 and the optimum time for its expression was found to be 6 h after isopropyl-β-D-thiogalactoside (IPTG) induction. Successful expression was confirmed by sodium dodecyl sulfate - polyacrylamide gel electrophoresis (SDS - PAGE) and western blot analysis which showed a protein with a molecular mass of ~94 kDa. The expressed protein was concentrated by size exclusion column with 30 MWCO and showed activity of 435 IU/ml and 401 IU/ml for hysA-S10 and hysA-S. aureus Newman recombinant proteins, respectively. The activity of recombinant protein in the spent media of the transformed E. coli BL21 was further analyzed under the effect of different pH, temperature and some chemical compounds

Relationship between antimicrobial prescribing and antimicrobial resistance among UTI patients at Buraidah Central Hospital, Saudi Arabia

Most of the decisions regarding diagnosis and treatment are based on laboratory test results. Urinary tract infections (UTIs) are among the most common infections in humans. The changing antimicrobial sensitivity in UTI requires appropriate antibiotics. Antimicrobial resistance is an emerging problem in the Kingdom of Saudi Arabia where the complete reversal of antimicrobial resistance is difficult due to irrational use of antibiotics. Objectives: This study aimed to determine the most common bacterial agents causing UTI in different seasons among patients who were admitted to Buraidah Central Hospital (BCH), Saudi Arabia. The study also evaluated the link between prescribing and resistance toward antimicrobials. Materials and Methods: A 6-month retrospective study was conducted among adult patients who were admitted to the inpatient department at BCH. A total of 379 files were collected from microbiological laboratory for inpatients. Results: Most UTI-causing bacteria prevailed in the same season. Of 15 bacterial strains, 12 were significantly correlated with 20 (of a total of 40) antibiotics that were used. Most bacteria were gram-negative. Gram-negative bacilli including Escherichia coli, Klebsiella spp., and Pseudomonadaceae and gram-positive Enterococcus faecalis were most frequently causing UTIs. Conclusion: Overall prevalence of antibiotic resistance was negative in bacterial isolates. However, the relationship between antimicrobial prescribing and antimicrobial resistance was significantly negative among UTI patients in BCH, Saudi Arabia

Discovery of two brominated oxindole alkaloids as staphylococcal DNA gyrase and pyruvate kinase inhibitors via inverse virtual screening

In the present study, a small marine-derived natural products library was assessed for antibacterial potential. Among 36 isolated compounds, a number of bis-indole derivatives exhibited growth-inhibitory activity towards Gram-positive strains (Bacillus subtilis and multidrug-resistant Staphylococcus aureus). 5- and 6-trisindoline (5-Tris and 6-Tris) were the most active derivatives (minimum inhibitory concentration, MIC, 4&ndash;8 &micro;M) that were subsequently selected for anti-biofilm activity evaluation. Only 5-Tris was able to inhibit the staphylococcal biofilm formation starting at a 5 &micro;M concentration. In order to investigate their possible molecular targets, both natural products were subjected to in silico inverse virtual screening. Among 20 target proteins, DNA gyrase and pyruvate kinase were the most likely to be involved in the observed antibacterial and anti-biofilm activities of both selected natural products. The in vitro validation and in silico binding mode studies revealed that 5-Tris could act as a dual enzyme inhibitor (IC50 11.4 &plusmn; 0.03 and 6.6 &plusmn; 0.05 &micro;M, respectively), while 6-Tris was a low micromolar gyrase-B inhibitor (IC50 2.1 &plusmn; 0.08 &micro;M), indicating that the bromine position plays a crucial role in the determination of the antibacterial lead compound inhibitory activity

Induction of antibacterial metabolites by co-cultivation of two Red-Sea-sponge-associated actinomycetes <i>Micromonospora</i> sp. UR56 and <i>Actinokinespora</i> sp. EG49

Liquid chromatography coupled with high resolution mass spectrometry (LC-HRESMS)-assisted metabolomic profiling of two sponge-associated actinomycetes, Micromonospora sp. UR56 and Actinokineospora sp. EG49, revealed that the co-culture of these two actinomycetes induced the accumulation of metabolites that were not traced in their axenic cultures. Dereplication suggested that phenazine-derived compounds were the main induced metabolites. Hence, following large-scale co-fermentation, the major induced metabolites were isolated and structurally characterized as the already known dimethyl phenazine-1,6-dicarboxylate (1), phenazine-1,6-dicarboxylic acid mono methyl ester (phencomycin; 2), phenazine-1-carboxylic acid (tubermycin; 3), N-(2-hydroxyphenyl)-acetamide (9), and p-anisamide (10). Subsequently, the antibacterial, antibiofilm, and cytotoxic properties of these metabolites (1&ndash;3, 9, and 10) were determined in vitro. All the tested compounds except 9 showed high to moderate antibacterial and antibiofilm activities, whereas their cytotoxic effects were modest. Testing against Staphylococcus DNA gyrase-B and pyruvate kinase as possible molecular targets together with binding mode studies showed that compounds 1&ndash;3 could exert their bacterial inhibitory activities through the inhibition of both enzymes. Moreover, their structural differences, particularly the substitution at C-1 and C-6, played a crucial role in the determination of their inhibitory spectra and potency. In conclusion, the present study highlighted that microbial co-cultivation is an efficient tool for the discovery of new antimicrobial candidates and indicated phenazines as potential lead compounds for further development as antibiotic scaffold

Epigenetic modifiers induce bioactive phenolic metabolites in the marine-derived fungus penicillium brevicompactum

Fungi usually contain gene clusters that are silent or cryptic under normal laboratory culture conditions. These cryptic genes could be expressed for a wide variety of bioactive compounds. One of the recent approaches to induce production of such cryptic fungal metabolites is to use histone deacetylases (HDACs) inhibitors. In the present study, the cultures of the marine-derived fungus Penicillium brevicompactum treated with nicotinamide and sodium butyrate were found to produce a lot of phenolic compounds. Nicotinamide treatment resulted in the isolation and identification of nine compounds 1&ndash;9. Sodium butyrate also enhanced the productivity of anthranilic acid (10) and ergosterol peroxide (11). The antioxidant as well as the antiproliferative activities of each metabolite were determined. Syringic acid (4), sinapic acid (5), and acetosyringone (6) exhibited potent in vitro free radical scavenging, (IC50 20 to 30 &micro;g/mL) and antiproliferative activities (IC50 1.14 to 1.71 &micro;M) against HepG2 cancer cell line. Furthermore, a pharmacophore model of the active compounds was generated to build up a structure-activity relationship

¹H-NMR metabolic profiling, antioxidant activity, and docking study of common medicinal plant-derived honey

The purpose of this investigation was to determine &sup1;H-NMR profiling and antioxidant activity of the most common types of honey, namely, citrus honey (HC1) (Morcott tangerine L. and Jaffa orange L.), marjoram honey (HM1) (Origanum majorana L.), and clover honey (HT1) (Trifolium alexandrinum L.), compared to their secondary metabolites (HC2, HM2, HT2, respectively). By using a &sup1;H-NMR-based metabolomic technique, PCA, and PLS-DA multivariate analysis, we found that HC2, HM2, HC1, and HM1 were clustered together. However, HT1 and HT2 were quite far from these and each other. This indicated that HC1, HM1, HC2, and HM2 have similar chemical compositions, while HT1 and HT2 were unique in their chemical profiles. Antioxidation potentials were determined colorimetrically for scavenging activities against DPPH, ABTS, ORAC, 5-LOX, and metal chelating activity in all honey extract samples and their secondary metabolites. Our results revealed that HC2 and HM2 possessed more antioxidant activities than HT2 in vitro. HC2 demonstrated the highest antioxidant effect in all assays, followed by HM2 (DPPH assay: IC50 2.91, 10.7 &mu;g/mL; ABTS assay: 431.2, 210.24 at 50 ug/mL Trolox equivalent; ORAC assay: 259.5, 234.8 at 50 ug/mL Trolox equivalent; 5-LOX screening assay/IC50: 2.293, 6.136 ug/mL; and metal chelating activity at 50 ug/mL: 73.34526%, 63.75881% inhibition). We suggest that the presence of some secondary metabolites in HC and HM, such as hesperetin, linalool, and caffeic acid, increased the antioxidant activity in citrus and marjoram compared to clover honey