Sulphonamide Compounds Research Articles

The evolutionary tale of eight novel plasmids in a colistin-resistant environmental Acinetobacter baumannii isolate.

Acinetobacter baumannii is an important opportunistic pathogen known for its high levels of resistance to many antibiotics, particularly those considered last resorts such as colistin and carbapenems. Plasmids of this organism are increasingly associated with the spread of clinically important antibiotic resistance genes. Although A. baumannii is a ubiquitous organism, to date, most of the focus has been on studying strains recovered from clinical samples ignoring those isolated in the environment (soil, water, food, etc.). Here, we analysed the genetic structures of eight novel plasmids carried by an environmental colistin-resistant A. baumannii (strain E-072658) recovered in a recycled fibre pulp in a paper mill in Finland. It was shown that E-072658 carries a new variant of the mcr-4 colistin resistance gene (mcr-4.7) in a novel Tn3-family transposon (called Tn6926) carried by a novel plasmid p8E072658. E-072658 is also resistant to sulphonamide compounds; consistent with this, the sul2 sulphonamide resistance gene was found in a pdif module. E-072658 also carries six additional plasmids with no antibiotic resistance genes, but they contained several pdif modules shared with plasmids carried by clinical strains. Detailed analysis of the genetic structure of all eight plasmids carried by E-072658 showed a complex evolutionary history revealing genetic exchange events within the genus Acinetobacter beyond the clinical or environmental origin of the strains. This work provides evidence that environmental strains might act as a source for some of the clinically significant antibiotic resistance genes.

New drugs to squash the spread of malaria

The human-infecting malaria parasite, Plasmodium falciparum (green), is depicted erupting from human red blood cells (red). Eight sexually mature parasites (male gametes, green) emerge from the human cell (red), with their replicating DNA shown in blue. This image is courtesy of Dr Sabrina Yahiya and Prof. Jake Baum. For permission to reuse, contact Jake Baum at jake.baum@unsw.edu.au.Malaria is a devastating disease, with 247 million cases and 619,000 deaths reported in 2021 alone. Drugs to treat malaria symptoms and insecticides to kill the mosquito vector have improved in recent decades, but the parasite – Plasmodium falciparum - and the mosquitoes are evolving to become resistant to these strategies. Therefore, there is an urgent need for new antimalarial drugs with new modes of action. An attractive target is to prevent P. falciparum transmission to the mosquito vector, a process that depends on sexual maturation of male and female parasites from their dormant gametocyte form into gametes, known as gametogenesis.With this aim, the Baum laboratory have been investigating the mode of action of a new class of antimalarial sulphonamides – known as N-[(4-hydroxychroman-4-yl)methyl]-sulphonamide (N-4HCS) compounds – which have previously been shown to potently block male gametogenesis. The authors cultured gametocytes in human erythrocytes and treated them with one of the N-4HCS compounds to identify potential targets. Using photo-affinity labelling and mass spectrometry, the authors identified the gametocyte-specific parasitophorous vacuole membrane (PVM) protein Pfs16 as having the most significant interaction with this N-4HCS compound. The team then used complementary techniques to confirm that this N-4HCS compound binds and blocks Pfs16 function, which is known to be indispensable for male gametogenesis.The authors proceeded to explore the activity window of this N-4HCS compound in male gametocytes. They activated the process of gametogenesis, and then treated the male gametocytes with the N-4HCS compound at staggered time points up to 25 minutes, which is the point of male gamete maturation. Impressively, the N-4HCS compound was able to traverse the erythrocyte membrane and act within zero to six minutes of male gametogenesis initiation to prevent completion of the process. Probing further, the team used immunofluorescence imaging to show that the N-4HCS compound blocked P. falciparum cytoskeleton rearrangements and prevented Pfs16-dependent breakdown of the PVM, both of which are essential for male gametogenesis.Overall, Baum and colleagues have identified how this new class of antimalarials block male gamete formation and, therefore, malaria transmission. Once thoroughly developed and tested, there is potential for N-4HCS compounds to be given to malaria patients alongside existing symptomatic therapies, or even delivered directly to mosquitoes by coating nets or sugar baits – both of which could diminish subsequent infection of humans. More research is under way to explore and refine the activity of this class of sulphonamides, but, nevertheless, this study expands the breadth of strategies available to be used in the fight against malaria.

A novel class of sulphonamides potently block malaria transmission by targeting a Plasmodium vacuole membrane protein.

Phenotypic cell-based screens are critical tools for discovering candidate drugs for development, yet identification of the cellular target and mode of action of a candidate drug is often lacking. Using an imaging-based screen, we recently discovered an N-[(4-hydroxychroman-4-yl)methyl]-sulphonamide (N-4HCS) compound, DDD01035881, that blocks male gamete formation in the malaria parasite life cycle and subsequent transmission of the parasite to the mosquito with nanomolar activity. To identify the target(s) of DDD01035881, and of the N-4HCS class of compounds more broadly, we synthesised a photoactivatable derivative, probe 2. Photoaffinity labelling of probe 2 coupled with mass spectrometry identified the 16 kDa Plasmodium falciparum parasitophorous vacuole membrane protein Pfs16 as a potential parasite target. Complementary methods including cellular thermal shift assays confirmed that the parent molecule DDD01035881 stabilised Pfs16 in lysates from activated mature gametocytes. Combined with high-resolution, fluorescence and electron microscopy data, which demonstrated that parasites inhibited with N-4HCS compounds phenocopy the targeted deletion of Pfs16 in gametocytes, these data implicate Pfs16 as a likely target of DDD01035881. This finding establishes N-4HCS compounds as being flexible and effective starting candidates from which transmission-blocking antimalarials can be developed in the future.

A conserved glutathione binding site in poliovirus is a target for antivirals and vaccine stabilisation

Strategies to prevent the recurrence of poliovirus (PV) after eradication may utilise non-infectious, recombinant virus-like particle (VLP) vaccines. Despite clear advantages over inactivated or attenuated virus vaccines, instability of VLPs can compromise their immunogenicity. Glutathione (GSH), an important cellular reducing agent, is a crucial co-factor for the morphogenesis of enteroviruses, including PV. We report cryo-EM structures of GSH bound to PV serotype 3 VLPs showing that it can enhance particle stability. GSH binds the positively charged pocket at the interprotomer interface shown recently to bind GSH in enterovirus F3 and putative antiviral benzene sulphonamide compounds in other enteroviruses. We show, using high-resolution cryo-EM, the binding of a benzene sulphonamide compound with a PV serotype 2 VLP, consistent with antiviral activity through over-stabilizing the interprotomer pocket, preventing the capsid rearrangements necessary for viral infection. Collectively, these results suggest GSH or an analogous tight-binding antiviral offers the potential for stabilizing VLP vaccines.

The discovery of hypoglycaemic sulphonamides – Montpellier, 1942

The pathophysiological study of diabetes mellitus took an important place in the school of Montpellier since the end of the XIXthcentury with Emmanuel Hedon's (1863-1933) contribution to the demonstration of the endocrine function of the pancreas. In 1942, a new sulfonamide compound (2254RP) was tested in the infectious diseases department of PrM.Janbon (1898-1996) on cases of typhoid fever, leading to several deaths rapidly related to hypoglycaemia. The physiologist Auguste Loubatières (1912-1977) rapidly demonstrated that this hypoglycaemic effect required the presence of pancreas and was explained by stimulation of insulin secretion. He contributed to the description of a hypoglycaemic effect of several other sulphonamide compounds. He considered the diagnostic and therapeutic relevance of this class of drugs. This is a good example of a medical discovery combining a favourable local environment, serendipity and perfect experimental approach.

Synthesis and characterisation of sulphonamide (Schiff base) ligand and its copper metal complex and their efficiency in polyurethane varnish as flame retardant and antimicrobial surface coating additives

Sulphonamide compounds are present in many bioactive compounds owing to their multiple biological applications, even their metal complexes. The study reported in this paper focused on the synthesis of a sulphonamide ligand (Schiff base) and its Cu metal complex and their possible applications as antimicrobial and flame retardant additives in polyurethane formulations for surface coating application. Thus, selected divalent (Cu II) metal complex of 4-((E)-(4-hydroxy-3-((E)-(p-tolylimino)methyl) phenyl) diazenyl)-N-(5-methylisoxazol-3-yl) benzenesulphonamide was prepared and characterised using a combination of elemental analysis, Fourier Transform Infrared, Proton Nuclear Magnetic Resonance and mass spectroscopy. The prepared Schiff base ligand and its Cu metal complex were physically added to polyurethane varnish to give varnish coating formulations at a laboratory scale and then applied onto pretreated wood and steel panels using a brush. The oxygen index, Gram negative bacteria; Gram positive bacteria and fungi values obtained indicated that the polyurethane varnish that contained the prepared ligand and its Cu metal complex as additives exhibited very good flame retardant and antimicrobial properties, respectively. It was also found that the metal complex had outperformed the ligand. The physical and mechanical resistance of the coatings was also studied, in order to assess any disadvantages owing to the incorporation of the additives. It was found that the additives did not influence the flexibility, hardness and adhesion of coating films prepared using the polyurethane varnish. The gloss of the polyurethane varnish film was improved due to the incorporation of the aromatic ring into the formulation.

New therapy from old drugs: synergistic bactericidal activity of sulfadiazine with colistin against colistin-resistant bacteria, including plasmid-mediated colistin-resistant mcr-1 isolates

The recent emergence of colistin (COL) resistance, particularly mcr-1 plasmid-mediated COL resistance in Gram-negative bacteria, has led to renewed interest in antibiotic combinations to overcome clinical therapeutic impasses. The aim of this study was to evaluate the potential of the synergistic and bactericidal activity of COL in combination with sulphonamide compounds, including sulfadiazine (SDI), sulfamethoxazole (SMX) and trimethoprim/sulfamethoxazole (SXT), as well as trimethoprim (TMP) against clinical COL-resistant bacterial strains, including strains with the plasmid-encoded mcr-1 gene. A collection of 55 COL-resistant and -susceptible strains from different origins (Laos, Thailand and France) was used in this study. Several in vitro methods were used to determine the potential of the synergistic activity of these combinations, including Etest on agar pre-treated plates, the Etest cross method and the chequerboard assay. A time–kill assay was performed to evaluate the potential bactericidal activity of combinations in addition to synergistic activity. Significant synergistic activity was observed with all combinations tested. The combination of COL + SDI presented the highest synergistic effect against the various species of COL-resistant strains (92.7%). For the other combinations, a synergistic effect was also observed but with lower frequency for COL + SMX (33.3%), COL + TMP (47.3%) and COL + SXT (31.5%). Synergy was observed independently of the COL resistance mechanism. These in vitro results suggest that the combination of COL + SDI would appear to be justifiable in patients with multidrug-resistant bacterial infections that cannot be treated with COL monotherapy.

Antimicrobial susceptibility of Riemerella anatipestifer strains isolated from geese and ducks in Hungary.

Riemerella anatipestifer causes anatipestifer disease in many avian species. A total of 185 R. anatipestifer strains isolated in Hungary between 2000 and 2014 from geese and ducks were tested against 13 antibiotics (ampicillin, doxycycline, enrofloxacin, erythromycin, florfenicol, flumequine, gentamicin, penicillin, spectinomycin, streptomycin, sulphamethoxazole-trimethoprim, sulphonamide compounds, and tetracycline) by the Kirby-Bauer disk diffusion method. The majority of the strains were susceptible to florfenicol (97.9%), ampicillin (95.1%), penicillin (93%), sulphamethoxazole-trimethoprim (92.4%), and spectinomycin (86.5%). The highest resistance rates were observed for flumequine, tetracycline, erythromycin and streptomycin (94%, 91.4%, 75.1% and 71.4% resistance, respectively). The resistance patterns showed some variation depending on the geographical origin of the strains. The average rate of extensive drug resistance was 30.3%, and its proportion tended to increase in the period examined.

Synthesis and carbonic anhydrase inhibitory properties of new spiroindoline-substituted sulphonamide compounds

New spiroindoline-substituted sulphonamide compounds were synthesised and their inhibitory effects on the activity of purified human carbonic anhydrase I and II were evaluated. Human carbonic anhydrase isoenzymes (hCA-I and hCA-II) were purified from erythrocyte cells by affinity chromatography. The inhibitory effects of the 14 synthesised sulphonamides (6a–n) on esterase activities of these isoenzymes were studied in vitro. In relation to these activities, the inhibition equilibrium constants (Ki) were determined. The results showed that all the synthesised compounds inhibited the carbonic anhydrase (CA) isoenzyme activity. Among them, 6b was found to be the most active (Ki: 0.042 μM) for hCA I and 6a (Ki: 0.151 μM) for hCA II.

Occurrence, Characterization, and Antimicrobial Susceptibility of Salmonella enterica in Slaughtered Pigs in Sardinia.

The aim of this study was to determine Salmonella occurrence in slaughtered finishing pigs and piglets and in slaughterhouse environment in order to characterize the isolates with phenotypical (antimicrobial testing) and molecular (PFGE, MLVA) methods. Nine slaughterhouses located in Sardinia were visited. Six hundred and eight samples collected from 106 pigs and 108 environmental samples were collected and analyzed. Salmonella was isolated in 65 of 504 (12.9%) samples from finishing pigs, with an occurrence of 15.1% in colon content, 12.7% in lymph nodes and liver, and 11.1% in carcass surface samples. Salmonella was never detected in piglets. The combined results of serotyping and PFGE showed a possible self-contamination in 71.5% of Salmonella positive carcasses of lymph nodes and/or colon content carriers, pointing out the role of healthy pigs for carcass contamination. A significantly higher (P < 0.05) occurrence was detected in finishing pigs of EC countries origin (23%) than in pigs of local farms (8%). Salmonella was also detected in 3.7% of environmental samples. The most prevalent serovar was S. Anatum, followed by S. Rissen, S. Derby, and monophasic S. Typhimurium. Resistance to at least 3 antimicrobial was observed in 97.1% of strains and 7 different patterns of multiple resistance were identified. The most common resistance was detected against sulphonamide compounds. A strict slaughterhouse application of hygiene standards is essential to control the risk of Salmonella contamination.

Detection of Salmonella enterica in pigs at slaughter and comparison with human isolates in Italy

In 2013–2014, 201 pigs belonging to 67 batches were tested for Salmonella in their mesenteric lymph nodes (MLN) in one abattoir of Northern Italy. For each batch, faecal material was collected at lairage by swabbing the pen floor for approximately 1600cm2. The aim of this study was to investigate the prevalence of Salmonella in MLN of pigs at slaughter, to assess Salmonella contamination at lairage and to evaluate the effect of lairage duration on its prevalence. Serotyping, XbaI PFGE typing and antimicrobial testing of the isolates were performed. Pig and human Salmonella isolates of the same region of Italy were compared to evaluate possible correlations.Salmonella enterica was isolated from 19.9% of the MLN and 49.3% of the environmental faecal samples. Nine different serovars were identified among 75 S. enterica isolates. In MLN Salmonella Derby was the most common (52.5%), followed by S. enterica 4,[5],12:i:- (17.5%) and Salmonella Rissen (10.0%). In faecal samples S. Derby was prevalent (51.4%), followed by S. enterica 4,[5], 12:i:- (20.0%) and Salmonella Brandenburg (14.3%).Lairage holding varied between 1 and ≥12h (median value: 2.5h). In pigs held for 1–3h, 14.1% were positive for Salmonella in MLN but the prevalence reached 31.8% when they were held for ≥12h. The contamination of MLN was statistically different (p=0.0045) between the two groups, thus confirming the role of long-lasting lairage in Salmonella contamination of pigs.XbaI PFGE typing detected 36 PFGE types. Twenty-three PFGE types were identified among the 40 MLN isolates and 22 PFGE types among the 35 faecal isolates. A total of 11 PFGE types were shared between the MLN of pigs and the lairage environment. Among S. Derby, 6 shared PFGE types between MLN and faeces were found and among S. enterica 4,[5],12:i:- one PFGE type was common between MLN and the faecal samples. Shared profiles between human and swine isolates of S. Derby, S. enterica 4,[5],12:i:-, S. Rissen, Salmonella Manhattan, S. Brandenburg, Salmonella Livingstone, Salmonella London and Salmonella Muenchen were identified. Among S. Derby and S. enterica 4,[5],12:i:- isolates found in pigs, 6/15 profiles (40.0%) and 8/10 (80.0%) were shared with human isolates.High resistance rates to streptomycin (97.3%), sulphonamide compounds (84.0%) and tetracycline (56.0%) were observed. No resistance was detected to ertapenem and meropenem. High proportions of isolates showed intermediate sensitivity to ciprofloxacin (85.3%) and cefotaxime (66.7%). High sensitivity rates were found to chloramphenicol (96.0%) and trimethoprim/sulfamethoxazole (81.3%).

N-myristoyltransferase is a cell wall target in Aspergillus fumigatus.

Treatment of filamentous fungal infections relies on a limited repertoire of antifungal agents. Compounds possessing novel modes of action are urgently required. N-myristoylation is a ubiquitous modification of eukaryotic proteins. The enzyme N-myristoyltransferase (NMT) has been considered a potential therapeutic target in protozoa and yeasts. Here, we show that the filamentous fungal pathogen Aspergillus fumigatus possesses an active NMT enzyme that is essential for survival. Surprisingly, partial repression of the gene revealed downstream effects of N-myristoylation on cell wall morphology. Screening a library of inhibitors led to the discovery of a pyrazole sulphonamide compound that inhibits the enzyme and is fungicidal under partially repressive nmt conditions. Together with a crystallographic complex showing the inhibitor binding in the peptide substrate pocket, we provide evidence of NMT being a potential drug target in A. fumigatus.

Synthesis, characterization and in vitro evaluation of novel enantiomerically-pure sulphonamide antimalarials.

Malaria parasites are currently gaining drug-resistance rapidly, across countries and continents. Hence, the discovery and development of novel chemical scaffolds, with superior antimalarial activity remain an important priority, for the developing world. Our report describes the development, characterization and evaluation of novel bepotastine-based sulphonamide antimalarials inhibiting asexual stage development of Plasmodium falciparum parasites in vitro. The screening results showed potent inhibitory activity of a number of novel sulphonamides against P. falciparum at low micromolar concentrations, in particular in late-stage parasite development. Based on computational studies we hypothesize N-myristoyltransferase as the target of the compounds developed here. Our results demonstrate the value of novel bepotastine-based sulphonamide compounds for targeting the asexual developmental stages of P. falciparum.

Synthesis, characterization and evaluation of in vitro antimicrobial activity of carbonyl derivatives of sulphonamide compounds

Synthesis, characterization and evaluation of in vitro antimicrobial activity of carbonyl derivatives of sulphonamide compounds

Detection, enumeration and characterization of Yersinia enterocolitica 4/O:3 in pig tonsils at slaughter in Northern Italy

Tonsils from 150 pigs slaughtered at 270days or older were tested for Yersinia enterocolitica with different cultural methods. Samples were collected in three different abattoirs of Northern Italy between April and November 2012 and were analysed by direct plating on cefsulodin–irgasan–novobiocin (CIN) agar and by enrichment procedures following the ISO 10273:2003 reference method. Twenty-three (15.3%) samples were positive: 22 tonsils (14.7%) were positive for human pathogenic Y. enterocolitica bio-serotype 4/O:3 and one tonsil (0.7%) for Y. enterocolitica bio-serotype 1A/7,8-8,8,19. Seventeen samples out of 23 (73.9%) were positive by direct plating method. Among the enrichment procedures, the best recovery rate (8 positives out of 23; 34.8%) was obtained by the two-day enrichment in peptone–sorbitol–bile (PSB) broth followed by plating on CIN agar plates. The two-day enrichment in PSB followed by potassium hydroxide (KOH) treatment before plating onto CIN agar gave 7 positives out of 23 (30.4%), decreasing to 3 positives (13.0%) without KOH treatment. The worst results were obtained by prolonged (five days) enrichment in PSB, with or without KOH treatment, followed by plating on CIN agar: 4.3% (1 out of 23) and 0.0% recovery rates, respectively. The mean concentration was 1.9×104CFU/g, with a minimum of 1.0×102CFU/g and a maximum of 5.8×104CFU/g, thus demonstrating that tonsils may play an important role in contamination of pluck sets, carcasses, and slaughterhouse environment.Prevalence of virulence genes among the Y. enterocolitica 4/O:3 isolates was as follows: 12/22 (54.5%) for yadA, 21/22 (95.5%) for ail, 21/22 (95.5%) for inv and 22/22 (100%) for ystA.All Y. enterocolitica 4/O:3 isolates were sensitive to amoxicillin/clavulanic acid, ciprofloxacin and ceftazidime and resistant to ampicillin and cephalotin. High proportions of 4/O:3 isolates (95%) were sensitive to cefotaxime, gentamicin, kanamicin and nalidixic acid. High levels of resistance were observed to sulphonamide compounds (91%), streptomycin (64%) and chloramphenicol (55%). Multi-resistant isolates were very common; resistance to three or more antimicrobials was observed in 91% (20/22) of 4/O:3 isolates. High level of resistance to chloramphenicol was possibly due to coresistance to tiamphenicol, which was detected in 100% of the isolates.XbaI-PFGE detected four clusters among the 22 Y. enterocolitica 4/O:3 isolates. The most represented accounted for 77% (17/22) of the isolates, the second most common was found in 14% (3/22) of the isolates and the two other profiles were observed in single isolates. The comparison with a selection of human isolates supported the role of the pig as reservoir of 4/O:3 Y. enterocolitica.

Prevalence, characterization and antimicrobial susceptibility of Salmonella enterica and Yersinia enterocolitica in pigs at slaughter in Italy

In 2005–2008, 1152 samples (451 faecal samples, 451 carcass swabs and 250 tonsils) were collected from 451 finishing pigs slaughtered in three abattoirs of northern Italy. In two abattoirs, 34 scalding water samples were collected. The aim of this study was to investigate the faecal and palatine tonsil carriage rate of Salmonella enterica and Yersinia enterocolitica in pigs at slaughter and the degree of carcass contamination by these bacteria. Typing of the isolates, virulence characterization and antimicrobial testing were also performed.S. enterica was isolated from 21.5% of the faecal samples, 10.9% of the carcasses and 10.4% of the tonsils, but not from scalding water. Nineteen different serovars were identified among 172 S. enterica isolates. The prevalent serovars were Derby (41.3%), Rissen (12.2%), Typhimurium (11%), 4,[5],12:i:— (8.7%) and Give (4.1%). S. enterica ser. Typhimurium and S. enterica ser. 4,[5],12:i:— isolates were phage-typed and PT DT120 was the most common (23.5%). Y. enterocolitica was detected in 17.1% of the faecal samples, 2.4% of the carcasses, 10.8% of the tonsils and 11.8% of the scalding water samples. A total of 119 isolates were found, four of them in water. Of the 115 Y. enterocolitica isolates of pig origin, 24 (20.9%) were 4/O:3 and 4 (3.5%) were 2/O:9. Y. enterocolitica 4/O:3 represented 85.7% of the pathogenic isolates found in all types of samples and 100% of those found in tonsils. In 4/O:3 isolates the most common virulence-associated genes were ystA (100%), inv (95.8%), ail (87.5%) and yadA (54.2%). In 2/O:9 isolates the prevalent genes were ail (100%), inv (100%) and ystA (100%), followed by ystB (25.0%). The majority (75.7%) of Y. enterocolitica isolates was biotype 1A, belonging to 13 serotypes (O:3; O:5; O:4,32-4,33; O:6,30-6,31; O:7,8-8; O:7,8-8-8,19; O:7,13; O:8; O:9; O:13; O:16-16,29; O:41,42-41,43; O:52). The most common virulence genes in 1A isolates were inv (95.4%) and ystB (72.4%).The antimicrobial resistance test showed that all Salmonella isolates were susceptible to cefotaxime, ciprofloxacin, cefalothin, gentamicin and enrofloxacin. Resistances to tetracycline (56%), sulphonamide compounds (42%) and streptomycin (34%) were the most common. All Y. enterocolitica isolates were susceptible to ciprofloxacin, ceftazidime, cefotaxime, chloramphenicol, enrofloxacin, gentamicin, kanamicin and neomycin. Most isolates were resistant to cefalothin (92%) and ampicillin (89%).Apparently, carcass contamination by S. enterica and Y. enterocolitica was more likely attributable to cross-contamination than to self-contamination, suggesting that good hygienic measures and slaughtering procedures can control transmission of these pathogens to pork meat.

QSAR-3D/CoMFA em compostos imídicos com atividade antinociceptiva

Imide compounds have shown biological activity. These compounds can be easily synthesized with good yields. The objective of this paper was the rational planning of imides and sulfonamides with antinociceptive activity using the 3D-QSAR/CoMFA approach. The studies were performed using two data sets. The first set consisted of 39 cyclic imides while the second set consisted of 39 imides and 15 sulfonamides. The 3D- QSAR/CoMFA models have shown that the steric effect is important for the antinociceptive activity of imide and sulphonamide compounds. Ten new compounds with improved potential antinociceptive activity have been proposed by de novo design leapfrog simulations.

The Identification of the Clinically-Important Sulphonamides

Summary A scheme is described for the identification of all the sulphonamide drugs at present available in this country. The six stages of the process are simple and rapid operations involving no unusual reagents or apparatus: (i) purification of the crude material by charcoal treatment in acetone solution, followed by melting-point determination. (ii) preliminary identification as a sulphonamide compound by decomposition with soda-lime. (iii) detection of free primary amino group by condensation with furfural. (iv) simple crystal tests based on precipitation from ammonia solution by acetic acid vapour. (v) vanillin confirmatory test for sulphamerazine and sulphadimidine. (vi) mixed melting-point determination.

Salmonella Serovars and Antimicrobial Resistance Patterns on a Sample of High Seroprevalence Pig Farms in England and Wales (2003-2008)

Following the introduction of a national abattoir-based monitoring programme for Salmonella in pigs, advisory visits were made to pig farms in England and Wales with high Salmonella seroprevalence assessed by muscle tissue fluid (meat juice) ELISA. Samples (n = 15 790), including pooled pen floor faeces (n = 12 136), were collected for Salmonella culture from 296 farms, between October 2003 and February 2008. Salmonella was isolated from 4489 (28%) of all samples collected, including 3301 (27%) of pooled pen floor faecal samples, from 270 (91%) of farms visited. Salmonella Typhimurium and S. Derby were the most prevalent serovars, representing 64% and 16% of isolates serotyped, respectively. The main phage types of S. Typhimurium identified were U288 and DT193. Antimicrobial resistance (AMR) was seen in 92% of isolates tested, with the highest frequencies of resistance occurring to tetracyclines (T), sulphonamide compounds (SU), ampicillin (AM), sulphamethoxazole/trimethoprim (SXT), streptomycin (S) and chloramphenicol (C). Fifty-nine AMR patterns were observed, the most frequent of these being T, AM, SXT, C, S, SU, seen in 35% of isolates tested. Multi-drug resistance was commonly found, with 67% of isolates submitted for AMR testing showing resistance to between four and nine antimicrobials.

Antibiotic resistance of Escherichia coli O157:H7 isolated from cattle and sheep

A total of 102 Escherichia coli O157:H7 colonies recovered from 11 cattle and 14 sheep were collected and tested for their antibiotic resistance profiles using a disc diffusion method, according to the Clinical and Laboratory Standards Institute. Four (36.36 %) of the 11 cattle E. coli O157:H7 isolates were resistant to cephalothin, one (9.09 %) isolate was resistant to streptomycin, and one (9.09 %) to nalidixic acid. Two (14.28 %) of the 14 sheep E. coli O157:H7 isolates were resistant to sulphamethoxazole, one (7.14 %) isolate was resistant to sulphonamide compounds, and one (7.14 %) to streptomycin. All cattle and sheep isolates were found to be susceptible to cephazolin, gentamicin, ciprofloxacin, imipenem, trimethoprim/ sulphamethoxazole, chloramphenicol, trimethoprim, and ceftiofur. Six cattle isolates were susceptible at a ratio of 54.54 %, and 11 (78.57 %) isolates from sheep were susceptible to all 20 antibiotics tested. As an overall result, 68 % of the E. coli O157:H7 isolates belonging to cattle and sheep were susceptible to all antibiotics tested. On the other hand, most of the E. coli O157:H7 isolates were intermediately resistant to streptomycin, cephalothin, sulphamethoxazole, ampicillin, and kanamycin.