Treatment challenges in the management of difficult-to-treat gram-positive infections: A consensus view apropos therapeutic role of novel anti-MRSA antibiotics, levonadifloxacin (IV) and alalevonadifloxacin (oral).

PURPOSE: Treatment of antibiotic-resistant Gram-positive infections (GPIs), including methicillin-resistant Staphylococcus aureus (MRSA) is becoming increasingly difficult, particularly in patients with multiple co-morbidities who require antibiotics with greater safety and a consistent pharmacokinetic/pharmacodynamic (PK/PD) profile. Such difficult-to-treat GPIs are often associated with poor outcomes, extended hospital stay and increased expenditure. This can be partly attributed to the limited safety and aberrant PK/PD profile of existing anti-MRSA antibiotics. In this context, intravenous levonadifloxacin and its oral prodrug alalevonadifloxacin are novel anti-MRSA antibiotics that have significant advantages over conventional anti-Gram-positive antibiotics. The purpose of this paper was to generate a consensus on the optimal use of levonadifloxacin and alalevonadifloxacin for tackling resistant Gram-positive infections in patients with multiple co-morbidities. METHOD: Using a modified Delphi approach that combines critical appraisal of evidence and expert opinion, therapeutic use of levonadifloxacin and alalevonadifloxacin in various clinical scenarios and specific unmet conditions was deliberated. Fifteen expert members from medicine, critical-care, emergency, microbiology, and intensive-care disciplines participated and voted on 11 pre-conceived statements. When there was at least 70 % agreement, a consensus was reached. RESULTS: Following the voting, agreements were reached on 10 out of the 11 statements. Broadly, a consensus was reached in defining the therapeutic role of levonadifloxacin and alalevonadifloxacin in the treatment of various clinical indications involving resistant Gram-positive pathogens, including MRSA, in patients with co-morbidities, such as co-existing or increased risk for kidney dysfunction or hepatic disease and/or immunosuppression; also, in therapeutically challenging conditions caused by Gram-positive bacteria such as bacteraemia, bone and joint infection, diabetic foot infection, febrile neutropenia, and hospital-acquired pneumonia. CONCLUSIONS: This consensus supports the therapeutic use of levonadifloxacin and alalevonadifloxacin in the treatment of antibiotic-resistant GPIs, including those caused by MRSA and certain polymicrobial infections, in patients with multiple co-morbidities requiring drug with adequate safety and consistent efficacy.

Deltamethrin-Induced Respiratory and Behavioral Effects and Adverse Outcome Pathways (AOP) in Short-Term Exposed Mozambique Tilapia, Oreochromis mossambicus.

Disrupted behavior and respiratory distress effects of 96-h acute deltamethrin exposures in adult Mozambique tilapia, Oreochromis mossambicus, were investigated using behavioral indices and opercular movement, respectively. Deltamethrin concentrations were found to be associated with toxicological (lethal and sublethal) responses. At 24, 48, 72, and 96 h, the LC50 values and 95% confidence limits were 12.290 (11.174-14.411 µg/L), 12.671 (11.334-15.649 µg/L), 10.172 (9.310-11.193 µg/L), and 8.639 (7.860-9.417 µg/L), respectively. The GUTS-model analysis showed that GUTS-SD (stochastic death) with a narrow tolerance distribution in deltamethrin exposed O. mossambicus populations was more sensitive than the GUTS-IT (individual tolerance) model. Prior to death, exposed fish demonstrated concentration-dependent mortality and disturbed behavioral responses, including uncoordinated swim motions, increased mucus secretion, unbalanced and unpredictable swimming patterns, and inactivity. The altered behavioral patterns and increased opercular movement with increased deltamethrin levels and exposure time are strongly suggestive of neurotoxicity and respiratory distress, respectively. Adverse Outcome Pathways (AOPs), describing biological mechanisms and plausible pathways, highlighted oxidative stress and cholinergic effects as intermediate steps linked to respiratory distress and behavioral toxicity.

Behavioral and physiological toxicity thresholds of a freshwater vertebrate (Heteropneustes fossilis) and invertebrate (Branchiura sowerbyi), exposed to zinc oxide nanoparticles (nZnO): A General Unified Threshold model of Survival (GUTS).

The toxic effects of Zinc oxide nanoparticles (nZnO) on Branchiura sowerbyi and Heteropneustes fossilis, was assessed in a 96-hour acute exposure regime using behavioral (including loss-of balance and clumping tendencies) and physiological (mucus secretion and oxygen consumption) endpoints. While the relationship between behavioral, physiological biomarkers, and exposure concentrations was assessed using correlation analysis, nZnO toxicity was further predicted using the General Unified Threshold model for Survival (GUTS). The time-dependent lethal limits for acute nZnO toxicity (LC50) on B. sowerbyi were estimated to be 0.668, 0.588, 0.448, and 0.400 mg/l, respectively, at 24, 48, 72, and 96 h whereas for H. fossilis the LC50 values are 0.954, 0.905, 0.874 and 0.838 mg/l. Threshold effect values i.e., LOEC (Lowest Observed Effect Concentration), NOEC (No Observed Effect Concentration), and MATC (Maximum Acceptable Toxicant Concentration) threshold effect values at 96 h were higher for fish compared to the oligochaete. For B. sowerbyi, the GUTS-SD (stochastic death) model is a better predictor of nanoparticle exposure effects compared to the GUTS-IT (individual tolerance) model, however in the case of H. fossilis, the reverse pattern was observed. Oxygen consumption rate was negatively correlated to mortality under acute exposure duration. The strong negative correlation between mortality and oxygen consumption strongly suggests a metabolic-toxicity pathway for nZnO exposure effects. The higher toxicity threshold values i.e., LOEC, NOEC, and MATC for fish compared to the oligochaete invertebrate indicates greater risks for invertebrates compared to vertebrates, with resultant implications for local habitat trophic relationships.

Antioxidant enzyme activity and pathophysiological responses in the freshwater walking catfish, Clarias batrachus Linn under sub-chronic and chronic exposures to the neonicotinoid, Thiamethoxam®.

The hydrophilic nature and resultant persistence of neonicotinoids in aquatic systems increase the exposure duration for non-target organisms. The sublethal toxicity of the neonicotinoid Thiamethoxam® spanning sub-chronic and chronic durations was investigated in Clarias batrachus, a non-target freshwater fish species. 96 h LC50 value of Thiamethoxam® on Clarias batrachus was 138.60 mg L-1. Pre-determined exposure concentrations of Thiamethoxam® (6.93 and 13.86 mg L-1) were used and effects were assessed at days 15, 30, and 45 exposure intervals. Biomarker effects were evaluated using antioxidant enzyme responses (CAT, SOD) neurotransmission (acetylcholinesterase activity), haematological and serum biochemistry changes (including haemoglobin content, total erythrocyte count, and serum albumin total leukocyte count, total serum protein, serum globulin, triglyceride, cholesterol, high-density lipoprotein, very low-density lipoprotein, low-density lipoprotein, phospholipid, and total serum glucose), histopathological alterations (gill and liver). Thiamethoxam®-exposed fish showed a marked reduction in haemoglobin content, total erythrocyte count, and serum albumin levels compared to control fish. Similarly, gill and liver antioxidant enzyme activity (CAT, SOD) and neurotransmission (acetylcholinesterase) also showed altered responses between sub-chronic exposure on day-15 and chronic responses on day-45. Histopathological observations in gill tissue revealed alterations ranging from vacuolation, hypertrophy, disruption of primary lamellar architecture, haemorrhage, the fusion of secondary lamella, and sloughing of outer epithelia. For liver tissue of exposed fish histopathological observations included increased sinusoidal spaces (ISS), necrosis of hepatocytes (NOH), nuclear degeneration (ND), disruption of architecture (DOA), macrophage infiltration of the central vein, vacuolation (V), hypertrophied hepatocytes, and haemorrhages. The gradients of toxic responses across exposure concentrations and depictions of impaired fish health with increasing thiamethoxam® exposure duration portend lowered physiological capacity for survival in the wild.

In vitro activity of Ceftazidime-Avibactam and its comparators against Carbapenem resistant Enterobacterales collected across India: results from ATLAS surveillance 2018 to 2019.

ATLAS (Antimicrobial Testing Leadership and Surveillance) detects trends in multi-drug resistance longitudinally over time. In the present study, the in vitro activity of ceftazidime-avibactam and comparators was analyzed against Escherichia coli (n = 458) and Klebsiella pneumoniae (n = 455)  isolates obtained from 9 centers across India. The overall susceptibility to ceftazidime-avibactam was observed to be 72% among K. pneumoniae isolates and 87% among E. coli isolates. Among the tested carbapenem resistant isolates, 51% of CR-K. pneumoniae and 24% of CR-E. coli were susceptible to ceftazidime- avibactam. OXA-48 like was identified in 52% of the K. pneumoniae isolates followed by co-production of NDM with OXA-48 like in 27%. NDM was predominantly identified in 68% of the E. coli isolates followed by OXA-48 like in 24% isolates. The findings suggest that ceftazidime- avibactam is a reasonable alternative to standard therapy for management of carbapenem resistant Enterobacterales infections particularly with K. pneumoniae and E. coli with the OXA-48 like genotype.

Effects of 2,4,6-Trichlorophenol on Clarias batrachus: a biomarkers approach.

2,4,6-Trichlorophenol (2,4,6-TCP) is a common waste among the resulting chlorophenols generated in the production of common products classified as an extremely toxic, mutagenic, carcinogenic and highly persistent xenobiotic in the environment. To evaluate the impact of 2,4,6-TCP in aquatic systems, the catfish species Clarias batrachus has been selected to test its toxicity due to its high market value and consumption in India. Here is presented the impact of this compound on different physiological parameters of fish: haematological parameters (haemoglobin, total erythrocyte count, total leucocyte count and mean corpuscular haemoglobin), biochemical parameters (total serum protein and total serum glucose), growth and reproductive parameters (condition factor, hepatosomatic index, maturity index, specific growth rate, growth hormone, 17ß-estradiol and testosterone), exposed to two concentrations of 2,4,6-TCP (0.5 mg/L and 1 mg/L - 1/10th and 1/20th of the LC50) for a period of 15, 30 and 45 days. The results showed that C. batrachus even when exposed to the lower concentration (0.5 mg/L) for the shortest time (15 days) negatively impacted the organism in all the assessed parameters. This was highlighted by the Integrated Biomarker Response index (IBR), showing worse scores for the treatments (up to 20 × worse than the control). This work highlights the importance of continued research on the impact of 2,4,6-TCP, on an important commercial, supported by the high environmental persistence of this compound that can reach the same range of tested concentrations.

Physiological (haematological, growth and endocrine) and biochemical biomarker responses in air-breathing catfish, Clarias batrachus under long-term Captan® pesticide exposures.

The sub-lethal toxicity of Captan® on selected haematological (Hemoglobin, Haematocrit, Mean Corpuscular Hemoglobin) growth (Condition factor, Hepatosomatic Index, Specific Growth Rate), biochemical (serum glucose, protein), and endocrine parameters (growth hormone, T3 and T4) in Clarias batrachus was examined under chronic exposures. Captan® was administered at predetermined exposure concentrations (0.53 and 1.06 mg/L) and monitored on days 15, 30, and 45 of the experimental periods. The experimental groups showed significantly lower values (p < 0.05) of haemoglobin content, hematocrit, MCH in Captan® exposed fish compared to control. Serum protein, k-factor and SGR were significantly lower in exposed fish. Endocrine responses (T3 and T4) emerged as the most sensitive biomarker category, depicting modulated responses between sub-chronic exposure at day-15 and chronic responses at day-45. In general, biomarker depictions indicate that Captan® exposures are capable of inducing stress-specific effects at the biochemical and physiological levels negatively impacting the overall health and longevity of such animals.

Distinctive Mobile Genetic Elements Observed in the Clonal Expansion of Carbapenem-Resistant Klebsiella pneumoniae in India.

Background: Klebsiella pneumoniae (Kp), a common multidrug-resistant pathogen, causes a wide spectrum of nosocomial infections with high rates of morbidity and mortality. The emergence of pan drug-resistant international high-risk clones such as ST258, ST14, ST15, ST147, and ST101 is a global concern. This study was performed to investigate the carbapenemases, the plasmid profile, and the clonal relationship among Indian K. pneumoniae. Materials and Methods: A total of 290 K. pneumoniae isolates from seven centers in India were characterized to determine sequence types (STs) and carbapenemases. A subset of isolates was subjected to whole genome sequencing and hybrid genome assembly to obtain the complete genome. Plasmids carrying carbapenemases were characterized to determine the dissemination of carbapenem-resistant (CR) K. pneumoniae. Results: From this study, 75 different STs were observed with ST231 being predominant. About 79% of the analyzed isolates were CR with 59% (n = 136) producing OXA48-like carbapenemases. While ST231 was the predominant clone among the OXA48-like producers; NDM producers and NDM+OXA48-like producers were mostly associated with ST14. Interestingly, 61% (n = 138) of the total CR K. pneumoniae were colistin resistant, belonging to 22 different STs. Plasmid profiling shows that blaOXA48-like was exclusively carried by ColKP3, whereas blaNDM was associated with IncFII-like plasmids. Conclusion: The highly mosaic genome of K. pneumoniae coupled with the diverse ecological niches in India makes it a hotspot for antimicrobial resistance, leading to increased morbidity and mortality. Extensive molecular surveillance of the clonal spread of K. pneumoniae could help in understanding AMR dynamics and thus rework therapeutic management.

A through-the-scope device for suturing and tissue approximation under EUS control.

BACKGROUND: The ability to place sutures under EUS control might allow development of a new type of transluminal endosurgery. The aim of this study was to develop endoscopic methods for suturing to variable predetermined depths in the wall of the GI tract and to allow fixation of adjacent hollow organs under EUS control. METHODS: A suturing device was constructed for suturing under EUS control to any desired depth. Sutures can also be placed into hollow or solid organs within 5 cm of the endoscope tip. The device allows multiple sutures to be placed without withdrawing the endoscope. Stitching, knot-tying, and thread-cutting are achieved through a 2.8-mm accessory channel. RESULTS: Multiple (>100) sutures were placed in predetermined gut wall layers in pigs. Sutures were placed in the gallbladder (n = 7) and small intestine (n = 8) to fix the gallbladder/small intestine to the stomach and allow traction for the insertion of stents and other devices through the 2 lumens. CONCLUSION: A new method for stitching under flexible EUS control is described. This technology was used to place sutures at precise depths in the GI tract. It allowed fixation of other organs to the accessible GI tract for various purposes including delivery of stents and devices for creating anastomoses.