Reliability of routine disc susceptibility testing by the British Society for Antimicrobial Chemotherapy (BSAC) method

OBJECTIVES

To ascertain the agreement between MICs determined at a central laboratory, and susceptible, intermediate and resistant categorizations based on zone diameters recorded at diagnostic laboratories using the BSAC standardized method.

METHODS

Standardized disc susceptibility tests were performed at sentinel laboratories in three surveys, with MIC tests performed on the collected isolates at a reference laboratory. The organisms comprised over 3300 Enterobacteriaceae, Acinetobacter spp., pseudomonads, staphylococci and enterococci, with over 29 000 antibiotic/organism tests in total.

RESULTS

More than 90% of the antibiotic/organism combinations classed as susceptible by disc tests in the sentinel laboratories were confirmed by MIC testing. Disagreements were more frequent where disc tests indicated resistance, with half of the piperacillin/tazobactam resistance and one-third of the cephalosporin resistance found in Enterobacteriaceae by disc tests not being confirmed, and with three-quarters of teicoplanin resistance in enterococci not confirmed. None of the few apparent cases of meropenem resistance in Enterobacteriaceae or linezolid, quinupristin/dalfopristin or vancomycin resistance in staphylococci were confirmed by MIC testing. When disagreements were found between disc- and MIC-based categorization, MICs were commonly, although not invariably, one to three doubling dilutions above or below the breakpoint. However, many of the disagreements where MICs were three or more dilutions from the breakpoint were not seen when disc tests were repeated in the central laboratory.

CONCLUSIONS

The BSAC disc method seems adequate for confirming susceptibility to guide therapy and to monitor resistance trends. Nevertheless, there must be concern about the over-estimation of many resistances, and frequent zone:MIC disagreements for isolates with borderline susceptibility.

Pulp mill process closure: a review of global technology developments and mill experiences in the 1990s

The impact of effluent discharges continues to be an important issue for the pulp manufacturing industry. Considerable progress has been made in pollution prevention to minimize waste generation, so-called manufacturing "process closure." Since the mid-1980s many important technologies have been developed and implemented, many of these in response to organochlorine concerns. Zero effluent operation is now a reality for a few bleached chemi-thermomechanical pulp (BCTMP) pulp mills. In kraft pulp manufacturing, important developments include widespread adoption of new cooking techniques, oxygen delignification, closed screening, improved process control, new bleaching methods, and systems that minimize pulping liquor losses. Coupled to this is a commitment to reduce water use and maximize reuse of in-mill process streams. Some companies pursued bleach plant closure, and many have been successful in eliminating a portion of their bleaching wastewaters. However, the difficulties inherent in closing bleach plants are considerable. For many mills the optimal solution has been found to be a high degree of closure coupled with external biological treatment of the remaining process effluent. No bleach plants at papergrade bleached kraft mills are known to be operating effluent-free on a continuous basis. This paper reviews the important worldwide technological developments and mill experiences in the 1990s that were focused on minimizing environmental impacts of pulp manufacturing operations.

Emergence of a fluoroquinolone-resistant strain of Streptococcus pneumoniae in England

OBJECTIVE

To determine the epidemiological relationship between pneumococci of serotype 9V, with reduced susceptibility to ciprofloxacin, penicillin and erythromycin, referred to the Reference Laboratory during 1997-2001.

METHODS

Isolates were characterized by multilocus sequence typing (MLST), PFGE, and sequencing of parC and gyrA. Relevant clinical data were sought.

RESULTS

Forty-eight isolates were received from nine laboratories in England, but 35 (73%) were from one laboratory in Birmingham, and were mostly from elderly patients receiving ofloxacin or ciprofloxacin for respiratory infections. There were two quinolone resistance phenotypes, with ciprofloxacin, moxifloxacin and gemifloxacin MICs of 8-32, 0.5-1 and 0.125-0.25 mg/L, and 64-256, 4-16 and 1-4 mg/L, respectively. Each of three isolates from the former group had mutations in parC, whereas each of nine isolates from the more resistant group had mutations in both parC and gyrA. Several also had increased quinolone efflux. Typing of 27 quinolone-resistant isolates showed that eight were indistinguishable from the epidemic Spain9V-3 (ST156) clone, while the remainder belonged to a novel but related type (ST609), that differed from Spain9V-3 at 2/7 alleles (2 bp changes in aroE and 1 bp change in gdh). Both MLST types were represented among isolates with high- and low-level quinolone resistance. Three of five serotype 9V isolates from Birmingham, with reduced susceptibility to penicillin and erythromycin, and ciprofloxacin MICs of 1-2 mg/L, belonged to MLST type ST609, while another was indistinguishable from the Spain9V-3 clone. Review of records of 32 patients from Birmingham indicated that some isolates were nosocomial, whereas others were acquired in the community.

CONCLUSIONS

In the late 1990s, a quinolone-resistant strain, clonally related to Spain9V-3, emerged in England, principally in Birmingham.

Susceptibility of Gram-positive bacteria from ICU patients in UK hospitals to antimicrobial agents

Microbiologists in 25 sentinel laboratories were each asked to refer up to 100 clinically-significant Gram-positive bacteria isolated from consecutive intensive care unit (ICU) patients. A total of 1595 isolates were collected from patients in 23 hospitals; these included Staphylococcus aureus (47.6%), coagulase-negative staphylococci (CNS) (30.6%), enterococci (14.3%), pneumococci (2.8%) and other streptococci (3.5%). A few coryneforms, other bacilli and a Nocardia sp. were also collected. Rates of oxacillin resistance among S. aureus and CNS isolates were 59.3 and 78.5%, respectively. Vancomycin-resistant S. aureus were not detected, although two isolates (0.3%) were resistant to teicoplanin [minimum inhibitory concentrations (MICs) 8 mg/L]. In contrast, 13.7% of CNS were teicoplanin resistant (MICs 8-32 mg/L) and 1.2% were resistant to vancomycin. Among the enterococci, 72.5% were Enterococcus faecalis and 24.5% were Enterococcus faecium, the remainder including isolates of Enterococcus casseliflavus or Enterococcus gallinarum. Eighteen percent of E. faecium isolates were vancomycin-resistant, compared with only 3% of E. faecalis isolates. Rates of high-level gentamicin resistance in E. faecalis and E. faecium were 40 and 25%, respectively. Nine percent of pneumococci and streptococci were resistant to penicillin, with 7 and 11%, respectively, resistant to erythromycin. None of the isolates showed resistance to linezolid, with the MICs for the entire study population falling in the range of 0.5-4 mg/L.

In vitro activity of piperacillin/tazobactam and other broad-spectrum antibiotics against bacteria from hospitalised patients in the British Isles

Piperacillin/tazobactam is used for empirical therapy of severe and complex infections. We assessed its activity, 9 years after launch, against consecutive, clinically significant isolates from in-patients in UK and Ireland. Standardised disc susceptibility tests were performed on 5031 isolates at 28 hospitals. For quality assurance purposes, 5% of these isolates were collected centrally for MIC tests, as were those with exceptional resistances. Compared with a similar pre-launch survey in 1991, there were major increases in the proportions of Staphylococcus aureus, Pseudomonas aeruginosa, beta-haemolytic streptococci and Enterococcus faecium isolates collected, balanced by decreases in Escherichia coli, Proteus mirabilis and coagulase-negative staphylococci. These changes in species prevalence mostly favoured organisms with inherent resistance(s) or-in the case of S. aureus-reflected the massive increase of MRSA, up from 0.7% of all isolates in 1991 to 14.8% in 2001. Based on the disc tests, piperacillin/tazobactam retained activity against 87% of Enterobacteriaceae isolates, 95% of P. aeruginosa, 99% of streptococci and 96% of Enterococcus faecalis. Resistance nevertheless had increased since 1991 in E. coli from 4 to 10%, Klebsiella spp. (5 to 21%) and in AmpC-inducible Enterobacteriaceae (17 to 23%), though not in P. mirabilis or P. aeruginosa. MIC tests confirmed most of the piperacillin/tazobactam resistance found by disc tests in Enterobacter spp., but indicated susceptibility for about half of the E. coli isolates recorded as resistant in disc tests. This situation might be remedied by reducing the zone breakpoint, but this would increase the "false susceptible" rate unacceptably. Thus, if disc tests suggest that an isolate is marginally resistant to piperacillin/tazobactam and the drug is sought as therapy, it is recommended that MIC be determined with, e.g., an Etest.

Haemangiopericytoma of the submental region

Haemangiopericytoma refers to an uncommon vascular/perivascular neoplasm of which a minority of cases arise in the head and neck. It comprises a group of lesions with marked clinical and pathological heterogeneity and a lack of positive criteria by which to make a definitive diagnosis. We describe an unusual case of such a tumour in the submental region, review its pathological features and discuss issues in management and prognosis.

Emerging linezolid-resistant Enterococcus faecalis and Enterococcus faecium isolated from two Austrian patients in the same intensive care unit

Of two patients in the same intensive care unit who were treated with linezolid, one yielded linezolid-resistant Enterococcus faecalis, whereas the other yielded linezolid-resistant Enterococcus faecium. In each case, molecular typing indicated that the resistant isolates were related to linezolid-susceptible isolates from the same patient, but differed from them by the same G2576U ribosomal RNA mutation. This is the first clinical case report of emerging resistance to linezolid among Enterococcus faecalis and also the first report of resistance involving vancomycin-susceptible rather than vancomycin-resistant enterococci. The linezolid-resistant isolates showed cross-resistance to the experimental oxazolidinone AZD2563, suggesting that oxazolidinone resistance might be a class effect.

Who performs thyroid surgery: a review of current otolaryngological practice

Thyroid surgery has been traditionally a general surgical practice, but recently more otolaryngologists have been offering a thyroid service. We have quantified thyroid surgery performed by the different specialties, and looked more closely at the practice of otolaryngologists. Data was obtained from the Department of Health for UK thyroid surgery in all specialties for the year 1998-99 and validated against a survey of members of the British Association of Otolaryngologists-Head & Neck Surgeons (BAO-HNS). The use of investigations of a simple clinical case (solitary thyroid nodule) was compared with best practice. General surgeons still perform the majority of thyroid surgery (83%) but ENT surgeons now perform significant numbers (15.4% of all cases), which translates to 1499 cases per annum. A total of 102 BAO-HNS members were performing thyroid surgery with an average case-load of 19.1 per year. In total, 35% of ENT surgeons see thyroid patients in multidisciplinary clinics. The choice of investigation is consistent with European guidelines. ENT surgeons are doing significant amounts of thyroid surgery and the numbers appear to be increasing. The formation of multidisciplinary teams including general surgeons and otolaryngologists who are committed to subspecialization can only improve both training and treatment outcomes.

Antimicrobial susceptibility of Gram-positive bacteria: what's current, what's anticipated?

Changing patterns of pathogens and antibiotic susceptibility present clinicians with difficult choices for antimicrobial prescribing. In particular, multiresistant staphylococci, enterococci and pneumococci present problems in many settings. The number of predictably active antimicrobials is decreasing in many centres, with significant consequences for both patients and society as a whole. New antimicrobial options have been few in recent years and several promising quinolones have been compromised by formulation and/or toxicity issues. Nevertheless, the recent introduction of linezolid and quinupristin/dalfopristin provides clinicians with valuable new options against Gram-positive cocci. These options should further increase with the likely introduction of daptomycin, oritavancin and tigilcycline. A range of surveillance programmes helps monitor the ever-changing patterns of resistance and thus guides clinicians in their empirical prescribing. Empirical use of powerful newer agents may be justifiable in seriously ill patients in those settings, units and countries where there is a substantial background rate of resistance.

Telithromycin. Aventis Pharma

The ketolide telithromycin (HMR-3647; Ketek), a derivative of clarithromycin, has been launched by Aventis Pharma (formerly Hoechst Marion Roussel) for the treatment of respiratory tract infections with gram-positive or gram-negative cocci, Haemophilus influenzae, Streptococcus pneumoniae, Moraxella catarrhalis, intracellular pathogens, atypical microorganisms, toxoplasma or anaerobic bacteria. By May 2001, filings in the US and EU had been completed and a filing in Japan was expected to take place in the fourth quarter of 2001. In July 2001, telithromycin was granted marketing authorization by the EC for the treatment of community-acquired respiratory tract infections, including those caused by bacteria resistant to commonly used antibiotics. In October 2001, the product was launched in Germany. In March 2000, telithromycin was submitted to the US FDA and the EMEA, under the EU centralized approval procedure, for approval for the treatment of community-acquired pneumonia (CAP), acute sinusitis, acute exacerbations of chronic bronchitis and tonsillitis/pharyngitis. The company had expected to launch the product in early 2001. The CPMP issued a positive opinion for all four indications on April 23 2001. In September 2001, the company indicated that it expected the product to be launched in Japan in 2002. The FDA's Anti-infectives Advisory Committee was due to review telithromycin for all the submitted indications on January 29 2001; however, this was postponed. This postponement was thought to be at Aventis' request in order to discuss the potential for a resistant pneumococcal infection labeling which would boost product sales. The revised date for the meeting was April 26 2001, at which the Anti-Infective Drugs Advisory Committee of the FDA recommended approval of telithromycin for the treatment of CAP in patients 18 years of age or older. The committee failed to recommend approval for the use of the drug for the remaining three indications for which it was filed, citing concerns over potential cardiovascular risk and liver toxicity; at this time, the company was in active discussions with the FDA regarding approval of the remaining three indications. An approvable letter for CAP, acute bacterial exacerbations of chronic bronchitis and acute bacterial sinusitis was received by the company in June 2001; Aventis also received a non-approvable letter for the treatment of tonsillitis/pharyngitis at this time. In April 1999, ABN Amro predicted annual sales of DM 50 million in 2001, rising to DM 100 million in 2002. In February 1999, Lehman Brothers estimated a 70% probability that this ketolide would come to market. The analysts also estimated a launch date of 2001, with peak sales of US $700 million in 2009. Analysts Merrill Lynch predicted in September 200, that the product would be launched by 2001, with sales of euro 50 million in that year, rising to euro 284 million in 2004. Deutsche Bank predicted in August 2001, that sales of the product would reach euro 5 million in 2001, rising to euro 300 million in 2005. Analysts at Merrill Lynch predicted in November 2001, that the product would be resubmitted in the US in mid-2002, and would make sales of US $5 million in 2001, rising to US $250 million in 2004.

NF kappa B and AP-1 mediate transcriptional responses to oxidative stress in skeletal muscle cells

The ability to induce cellular defense mechanisms in response to environmental challenges is a fundamental property of eukaryotic and prokaryotic cells. We have previously shown that oxidative challenges lead to an increase in antioxidant enzymes, particularly glutathione peroxidase (GPx) and catalase (CAT), in mouse skeletal muscle. The focus of the current studies is the transcriptional regulatory mechanisms responsible for these increases. Sequence analysis of the mouse GPx and CAT genes revealed putative binding motifs for NF kappa B and AP-1, transcriptional regulators that are activated in response to oxidative stress in various tissues. To test whether NF kappa B or AP-1 might be mediating the induction of GPx and CAT in muscle cells subjected to oxidative stress, we first characterized their activation by pro-oxidants. Electrophoretic mobility shift assays showed that oxidative stress led to increases in the DNA binding of NF kappa B in differentiated muscle cells. The NF kappa B complexes included a p50/p65 heterodimer, a p50 homodimer, and a p50/RelB heterodimer. AP-1 was also activated, but with slower kinetics than that of NF kappa B. The major component of the AP-1 complexes was a heterodimer composed of c-jun/fos. To test for redox regulation of NF kappa B- or AP-1-dependent transcriptional activation, muscle cells expressing either kappa B/luciferase or TRE/luciferase reporter constructs were subjected to oxidative stress. Pro-oxidant treatment resulted in increased luciferase activity in cells expressing either construct. To test whether NF kappa B mediates oxidant-induced increases of GPx and CAT expression, we transfected cells with either a transdominant inhibitor (I kappa B alpha) or a dominant-negative inhibitor (Delta SP) of NF kappa B. Both inhibitors blocked the induction of antioxidant gene expression by more than 50%. In summary, our results suggest that NF kappa B and AP-1 are important mediators of redox-responsive gene expression in skeletal muscle, and that at least NF kappa B is actively involved in the upregulation of the GPx and CAT in response to oxidative stress.

Activity of the ketolide telithromycin (HMR-3647) against erythromycin-susceptible and -resistant pneumococci isolated in the UK

The novel ketolide telithromycin (formerly HMR-3647) was tested against a collection of pneumococci of varying sensitivity to erythromycin and clindamycin, isolated in geographically diverse UK hospitals. Telithromycin was highly active against erythromycin-susceptible pneumococci, the MIC(90) being 0.015 mg/l. Erythromycin-resistant pneumococci that contained the ermB gene, either alone or together with the mefE gene, were cross-resistant to other macrolides and to clindamycin, while erythromycin-resistant pneumococci that contained only the mefE gene were cross-resistant to azithromycin, clarithromycin and roxithromycin but remained susceptible to josamycin and clindamycin. Telithromycin was active against erythromycin-resistant pneumococci irrespective of their mechanism of macrolide resistance, although the MIC(90) (0.25 mg/l) was higher than that seen with erythromycin-sensitive isolates. Telithromycin thus appears to be a potentially useful drug in settings where pneumococcal resistance to macrolides is prevalent.

What is the value of ENT specialist outreach clinics?

Ear, nose and throat (ENT) specialist outreach clinics, in which hospital-based consultants hold clinics in general practice surgeries, have been popular with general practitioners (GPs) and patients. This prospective study recorded data on 1155 consecutive patients seen by one ENT surgeon in two GP surgeries. At each consultation, a record was kept of the requirement for further investigations that would normally be done at the same time as the consultation in a hospital department. The results showed that 76 per cent of patients needed an investigation, which would be readily available in a hospital but not in a GP surgery (audiometry, endoscopy, microscopy of the ear, a minor procedure or X-ray). This study indicates that despite the apparent convenience of outreach ENT clinics to patients and GPs, patients may need to spend more time being assessed than they would if they were investigated in one visit to a hospital department. Unless an outreach clinic is used frequently, it is difficult to justify the cost of equipping it to the same level as a hospital department. Limited resources would be better spent providing good access to well-equipped regularly-used hospital ENT outpatient departments.

Activity of moxifloxacin and other quinolones against pneumococci resistant to first-line agents, or with high-level ciprofloxacin resistance

The activity of moxifloxacin and other quinolones was assessed against 288 epidemiologically diverse isolates of Streptococcus pneumoniae, many of them resistant to one or more first-line agents and/or with increased ciprofloxacin resistance (minimum inhibitory concentrations, MICs 16- > 64 mg/l compared with 1-2 mg/l for most isolates). Moxifloxacin and grepafloxacin were the most active quinolone analogues, inhibiting about 90% of the isolates at < or = 1 mg/l, whereas levofloxacin inhibited 64% of isolates at < = 1 mg/l and ciprofloxacin inhibited 42%. Moxifloxacin also was the most active agent against isolates with elevated ciprofloxacin resistance (MIC 16- > 64 mg/l): moxifloxacin MICs of around 4 mg/l were seen for most such isolates, compared with 16-32 mg for levofloxacin and grepafloxacin. The activity of moxifloxacin against pneumococci resistant to one or more first-line agent suggests it will have a useful therapeutic role, although its activity against highly ciprofloxacin resistant isolates seems marginal.

Activity of moxifloxacin against clinical isolates of Streptococcus pneumoniae from England and Wales

The activity of moxifloxacin was assessed against 1269 isolates of Streptococcus pneumoniae, comprising 462 isolates referred from UK hospitals, primarily for confirmation of resistance to first line agents, and 807 isolates from an enhanced surveillance of invasive infections. Resistance rates to penicillin, erythromycin, tetracycline and chloramphenicol were 88.7% (32.6% intermediate and 56.1% fully resistant), 50, 48 and 22.7%, respectively, for the former, and 8.0 (4.5% intermediate and 3.5% fully resistant), 14.7, 9.0 and 0.6% for the latter. Ninety-four per cent of the referred isolates and 99% of the surveillance isolates were susceptible to moxifloxacin at <or=1 mg/L. Moxifloxacin may therefore be a useful drug for the treatment of patients with pneumococcal infections due to antibiotic-resistant strains or those with severe invasive disease.

Anti-MRSA cephalosporins Bristol-Myers Squibb

BMS is investigating a series of cephalosporins for potential use in the treatment of methicillin-resistant Staphylococcus aureus (MRSA) infection [274213]. In vitro activity tests resulted in a minimum inhibitory concentration (MIC) of 1 to 8 microg/ml against MRSA 1274213]. A series of C(3) benzoyloxymethyl cephalosporins exhibited in vitro activity against MRSA and methicillin-susceptible Staphylococcus aureus (MSSA), with MIC values ranging from 0.007 to 2 microM, and improved in vivo stability in human plasma [258890].

Susceptibility of gram-positive cocci from 25 UK hospitals to antimicrobial agents including linezolid. The Linezolid Study Group

The prevalence of antibiotic resistance amongst Gram-positive cocci from 25 UK hospitals was studied over an 8 month period in 1999. A total of 3770 isolates were tested by the sentinel laboratories using the Etest; these bacteria comprised 1000 pneumococci, 1005 Staphylococcus aureus, 769 coagulase-negative staphylococci (CNS) and 996 enterococci. To ensure quality, 10% of the isolates were retested centrally, as were any found to express unusual resistance patterns. The prevalence of penicillin-resistant Streptococcus pneumoniae, vancomycin-resistant enterococci and methicillin-resistant S. aureus (MRSA) varied widely amongst the sentinel laboratories. The resistance rates to methicillin among S. aureus and CNS were 19.2 and 38.9%, respectively, with MRSA rates in individual sentinel sites ranging from 0 to 43%. No glycopeptide resistance was seen in S. aureus, but 6.5% of CNS isolates were teicoplanin resistant and 0.5% were vancomycin resistant. Vancomycin resistance was much more frequent among Enterococcus faecium (24.1%) than E. faecalis (0.5%) (P<0.05), with most resistant isolates carrying vanA. The rate of penicillin resistance in pneumococci was 8.9%, and this resistance was predominantly intermediate (7.9%), with only six hospitals reporting isolates with high level resistance. The prevalence of erythromycin resistance among pneumococci was 12.3%, with the majority of resistant isolates having the macrolide efflux mechanism mediated by mefE. All the organisms tested were susceptible to linezolid with MICs in the range 0.12-4 mg/L. The modal MICs of linezolid were 1 mg/L for CNS and pneumococci, and 2 mg/L for S. aureus and enterococci. Linezolid was the most potent agent tested against Gram-positive cocci, including multiresistant strains, and as such may prove a valuable therapeutic option for the management of Gram-positive infections in hospitals.

A simple and effective frontal sinus stent

We describe a frontal sinus stent which is cheap, easily produced and effective.

Male-killing Wolbachia in Drosophila: a temperature-sensitive trait with a threshold bacterial density

Inherited microorganisms that disturb the reproduction of their host have been characterized from a number of host taxa. To understand the general principles underlying the genetic and mechanistic basis of interactions, study of different agents in model host species is required. To this end, the nature and genetics of the maternally inherited sex-ratio trait of Drosophila bifasciata were investigated. Successful curing of affected lines with antibiotics demonstrated this trait was associated with the presence of a bacterium, and molecular systematic analysis demonstrated an association between the presence of the trait and infection with an A group Wolbachia. The penetrance and heritability of the trait did not vary with maternal age. Exposure to elevated temperatures did reduce trait penetrance but did not affect heritability. Examination of the effect of temperature on bacterial density in eggs revealed a decrease in bacterial density following exposure of the parent to elevated temperature, consistent with the hypothesis that male killing in D. bifasciata requires a threshold density of Wolbachia within eggs. The male offspring produced following exposure to elevated temperatures were infected with Wolbachia on emergence as adults. Crossing studies demonstrated a weak cytoplasmic incompatibility phenotype exhibited by Wolbachia in these males. The results are discussed with respect to the incidence of male killing within the clade Wolbachia, the general nature of Wolbachia-host interactions, and the prospects for using this association to investigate the mechanism of male killing.

Regional variation in ampicillin and trimethoprim resistance in Escherichia coli in England from 1990 to 1997, in relation to antibacterial prescribing

Over 200 hospitals in England report resistance data for bacteraemia and meningitis isolates to the Public Health Laboratory Service. We reviewed ampicillin and trimethoprim resistance rates from 1990 to 1997 for Escherichia coli, which is the species reported most frequently from these bacteraemias. Ampicillin resistance was relatively stable over time, but varied between Health Regions. The proportion of ampicillin-resistant E. coli in the East Anglia region remained </=42% in all years except one and that in the South Western region always remained <50%. At the other extreme, the proportions of ampicillin-resistant isolates in the Northern and Trent regions never fell below 59%. The prevalence of resistance to trimethoprim rose over time in most regions; again, however, the prevalence of resistant isolates was lowest in the East Anglia and South Western regions, whereas the highest resistance rates were reported from Mersey, NW Thames, NE Thames and North Western regions. These observations were related to data for community prescribing, which accounts for most ampicillin and trimethoprim use. Prescribing data for ampicillin and trimethoprim from 1987 to 1997 were obtained from the IMS-HEALTH Medical Data Index, and data for all antibacterial drugs between 1995 and 1997 from the Prescription Pricing Authority. Correlations between resistance rates and prescribing of specific antibiotics were weak, although there was some trend for regions with high total prescribing to have higher rates of ampicillin resistance. The South Western region was conspicuous both for low rates of resistance and low prescribing. Several factors may determine the lack of wider and more obvious relationships between resistance and prescribing. In particular, regions may be inappropriately large areas to test the relationship, isolates from bacteraemias may not be representative of those experiencing selection pressure in the community and the resistance data may have been distorted by nosocomial strains, although this seems unlikely with E. coli.

Pazufloxacin Toyama Chemical Co

Toyama Chemical Co Ltd is developing pazufloxacin (T-3761), an orally active synthetic quinolone antibiotic, which is awaiting registration following successful clinical trials that demonstrated its pharmacological similarities to tosufloxacin (Toyama Chemical Co) with respect to clinical efficacy, adverse effects and overall safety [272136]. As of June 2000, the company had filed an NDA for marketing approval in Japan [373027]. The company is also developing an injectable formulation, pazufloxacin mesylate (T-3762), which has entered phase III trials in Japan [228819]. There is a licensing agreement with Welfide Corp (formerly Yoshitomi/The Green Cross Corp) in Japan [228819].

A novel method of aligning molecules by local surface shape similarity

A novel shape-based method has been developed for overlaying a series of molecule surfaces into a common reference frame. The surfaces are represented by a set of circular patches of approximately constant curvature. Two molecules are overlaid using a clique-detection algorithm to find a set of patches in the two surfaces that correspond, and overlaying the molecules so that the similar patches on the two surfaces are coincident. The method is thus able to detect areas of local, rather than global, similarity. A consensus overlay for a group of molecules is performed by examining the scores of all pairwise overlays and performing a set of overlays with the highest scores. The utility of the method has been examined by comparing the overlaid and experimental configurations of 4 sets of molecules for which there are X-ray crystal structures of the molecules bound to a protein active site. Results for the overlays are generally encouraging. Of particular note is the correct prediction of the 'reverse orientation' for ligands binding to human rhinovirus coat protein HRV14.

Susceptibility to quinupristin/dalfopristin and other antibiotics of vancomycin-resistant enterococci from the UK, 1997 to mid-1999

Susceptibility to quinupristin/dalfopristin and other antibiotics was studied for clinical isolates of vancomycin-resistant enterococci (VRE) referred by UK hospitals between January 1997 and June 1999. Single isolates of VRE from 858 patients in 136 hospitals were received, of which 76% were Enterococcus faecium and 21% were Enterococcus faecalis, the remainder comprising minor species. Most isolates were multi-resistant. After allowing for the effect of blood, which raised the MICs of quinupristin/dalfopristin four-fold, 98.3% of E. faecalis isolates and all the Enterococcus avium, Enterococcus casseliflavus and Enterococcus gallinarum appeared resistant to quinupristin/dalfopristin, whereas 98.8% of the E. faecium isolates and the single Enterococcus raffinosus isolate were susceptible.

Plasmid-mediated vanB glycopeptide resistance in enterococci

Enterococcus faecium, which was highly resistant to vancomycin (MIC 256 mg/liter), but susceptible to teicoplanin (MIC 2 mg/liter), caused two distinct episodes of infection on a renal unit in the United Kingdom. Pulsed field gel electrophoresis (PFGE) indicated that a single strain caused the first episode, while the second episode, which occurred 1 year later, involved multiple strains, all of which were distinct from the original strain. Vancomycin resistance in all but one of these strains was mediated by transferable plasmids that carried the vanB glycopeptide resistance gene. Transfer either of resistance plasmids or the vanB resistance determinant itself to different strains occurred during the second episode. Plasmid-mediated vanB resistance has not been widely documented. A retrospective study of a reference collection revealed two other vanB-encoding plasmids from an E. faecalis and an E. faecium referred from two further UK centers. Although restriction analysis indicated no similarity between the plasmids from the three different centers, all contained a 2.1-kb EcoRV fragment that hybridized with a probe for the vanB gene. This suggests that there has been dissemination of a conserved glycopeptide resistance determinant, of which vanB is a part.

Are routine sensitivity test data suitable for the surveillance of resistance? Resistance rates amongst Escherichia coli from blood and CSF from 1991-1997, as assessed by routine and centralized testing

Surveillance of antibiotic resistance can be undertaken by compilation of routine data or by central testing of isolates. Routine results can be obtained cheaply and in sufficient quantities for correlation with population and prescribing denominators but there is concern about their quality. As one of a series of ongoing studies to assess this quality, we compared the proportions of resistance amongst Escherichia coli from patients with bacteraemia or meningitis between 1991 and 1997 (i) as recorded in routine data reported to the PHLS and (ii) as found in tests performed at the PHLS Laboratory of Enteric Pathogens (LEP). These two data sets both showed an overall upward trend in the proportion of isolates resistant to ampicillin, trimethoprim, gentamicin and ciprofloxacin. The average annual percentage increase in resistance was estimated in separate logistic regression models, and 95% confidence intervals (CI) were determined. The annual percentage increases in the proportions of isolates reported resistant were similar in the two data sets for trimethoprim, gentamicin and ciprofloxacin but differed for ampicillin. The upward trends were statistically significant except for gentamicin resistance in the LEP data set, where the 95% CI straddled zero. The proportions of resistant isolates for each antibiotic in the two data sets each year were in poorer agreement than the trends; however, the 95% CI of the difference of proportions resistant between the routine and LEP data sets straddled zero in 4 or 5 of the 7 years studied. Some discrepancies might be explained by geographical bias in the sampling or by differences in definitions of resistance. Thus (i) the proportion of resistant isolates tested at LEP almost always fell within the ranges bounded by the highest and lowest proportions for individual Regional Health Authorities, as recorded in the routine data, and (ii) the fact that LEP consistently recorded less gentamicin resistance but more ciprofloxacin resistance than the routine could be explained by breakpoint differences. We conclude that routine susceptibility data for ampicillin, ciprofloxacin, gentamicin and trimethoprim appear sound for E. coli and might be suitable for correlation with other data, e.g. for prescribing.

Activity of linezolid against multi-resistant gram-positive bacteria from diverse hospitals in the United Kingdom

The in vitro activity of linezolid, an oxazolidinone, was assessed against 374 gram-positive cocci, with an emphasis on testing multi-resistant, epidemiologically unrelated isolates. MICs of linezolid for staphylococci, pneumococci and streptococci had a narrow range, from 0.5 to 2 mg/L, whereas MICs for enterococci were uniformly 4 mg/L. For all the species tested, the MICs of linezolid were unrelated to those of other antimicrobials. Linezolid appears to be a potentially useful drug for infections caused by gram-positive cocci.

Bacteraemia and antibiotic resistance of its pathogens reported in England and Wales between 1990 and 1998: trend analysis

OBJECTIVES

Determination of causes, trends, and antibiotic resistance in reports of bacterial pathogens isolated from blood in England and Wales from 1990 to 1998.

DESIGN

Description of bacterial isolates from blood, judged to be clinically significant by microbiology staff, reported to the Communicable Disease Surveillance Centre.

SETTING

Microbiology laboratories in England and Wales.

SUBJECTS

Patients yielding clinically significant isolates from blood.

MAIN OUTCOME MEASURES

Frequency and Poisson regression analyses for trend of reported causes of bacteraemia and proportions of antibiotic resistant isolates.

RESULTS

There was an upward trend in total numbers of reports of bacteraemia. The five most cited organisms accounted for over 60% of reports each year. There was a substantial increase in the proportion of reports of Staphylococcus aureus resistant to methicillin, Streptococcus pneumoniae resistance to penicillin and erythromycin, and Enterococcus faecalis and Enterococcus faecium resistance to vancomycin. No increase was seen in resistance of Escherichia coli to gentamicin.

CONCLUSIONS

Reports from laboratories provide valuable information on trends and antibiotic resistance in bacteraemia and show a worrying increase in resistance to important antibiotics.

Outcome of surgery for acromegaly--the experience of a dedicated pituitary surgeon

Previous large series of outcome following pituitary surgery for acromegaly, including our own, have demonstrated poor results, with cure, defined as GH <5 mU/l, achieved in only 33-42% of patients. In our previous series, surgery was performed by one of eight different surgeons. Largely based on the disappointing results of this previous audit of outcome, our practice since 1990 has been, whenever possible, to refer all patients with acromegaly to a dedicated pituitary surgeon (APJ). The objective of the current study was to re-analyse the outcome of surgical treatment for acromegaly since instituting this change. Tumour size and extension was determined on CT/MRI scanning. Biochemical cure was defined as a basal GH <5 mU/l or a nadir GH of <2 mU/l across an OGTT following initial pituitary surgery. Surgery was performed on 66 patients and 42 (64%) were cured, compared with 26/78 (33%) in our previous study (p<0.0005, chi (2) test). The cure rate for microadenomas (n=22) was 86%, and for macroadenomas 52%, compared with 54% (p<0.05, chi (2) test) and 30% (p<0.05, chi (2) test) respectively, in our previous study. We conclude that surgical outcome for acromegaly is enhanced if patients are operated on by a single experienced surgeon.

Relationship between mutations in parC and gyrA of clinical isolates of Streptococcus pneumoniae and resistance to ciprofloxacin and grepafloxacin

The mechanisms of resistance to ciprofloxacin and grepafloxacin were studied in 54 clinical isolates of Streptococcus pneumoniae. Restriction fragment length polymorphism analysis following HinfI digestion was used with DNA sequencing to identify mutations in the quinolone resistance-determining regions (QRDRs) of the parC and gyrA genes. Ciprofloxacin MICs up to 16 mg/L were not associated with mutations to these genes in approximately half of the isolates. In other isolates, moderate levels of ciprofloxacin resistance (MIC 8-16mg/L) were associated with an alteration of ParC, most commonly entailing replacement of serine-79 by phenylalanine. High-level ciprofloxacin resistance (MIC 32-128 mg/L) entailed the additional mutation of GyrA with substitution of serine-83 by phenylalanine. Grepafloxacin MICs >4 mg/L were associated with this GyrA mutation alone; no relationship was detected between grepafloxacin MICs and mutation of the QRDR of parC.

Admission rates, early readmission rates and patient acceptability of 142 cases of day case septoplasty

Day case surgery should be confined to those procedures where less than 3% of patients require admission. The aim of this study was to establish the admission rates, early readmission rates and patient acceptability of 142 consecutive cases of day case septoplasty. Data acquisition was by retrospective postal questionnaire. One hundred and fifty-three patients were studied and data was acquired on 142. Ninety per cent (128/142) of patients had operations on afternoon lists. Admissions were 7/142 (5%), the early readmission rate (within 24 h) was 0% and 25/142 (17%) of patients felt they would rather have stayed in hospital for the first night after surgery. The conclusion of this work is that day case septoplasty is an acceptable practice in appropriately selected patients who are operated upon in the morning and when the technique described here is applied. An acceptably small proportion of planned day cases may require admission.

Gonococcal infection of human fallopian tube mucosa in organ culture: relationship of mucosal tissue TNF-alpha concentration to sloughing of ciliated cells

BACKGROUND AND OBJECTIVES

An experimental model consisting of gonococcal infection of human fallopian tube mucosa in organ culture has proven useful in studying the molecular pathogenesis of acute gonococcal salpingitis and postsalpingitis sequelae. Gonococcal infection of human fallopian tube mucosa in organ culture results in the sloughing of ciliated epithelial cells from the mucosa. This damage to the mucosa can be quantified on fallopian tube pieces by an assay of the percent of the periphery that has ciliary activity (PPCA) remaining at specific time points after infection. Although assay of the PPCA has been quite valuable, it is labor-intensive, somewhat subjective, and requires that the observers have training and experience. A more practical assay for genital mucosal damage is desirable for further investigations that employ the fallopian tube experimental model. Gonococcal infection of fallopian tube mucosa in organ culture also results in the production of easily quantified tumor necrosis factor-alpha (TNF-alpha) by the mucosa. Furthermore, treatment of the organ cultures with recombinant human TNF-alpha (rHuTNFalpha) alone also causes sloughing of ciliated cells from the mucosa. These findings strongly suggest that TNF-alpha is a mediator of the mucosal damage that attends gonococcal infection.

GOALS OF THE STUDY

To determine: (1) whether the PPCA values and the TNF-alpha concentrations in fallopian tube mucosal tissues correlate closely enough to allow prediction of the PPCA from a measurement of the mucosal tissue TNF-alpha concentration; and (2) whether the correlation of the TNF-alpha mucosal tissue concentration with the sloughing of ciliated cells (measured by the PPCA) supports the hypothesis that induction of TNF-alpha by gonococcal infection, with resultant sloughing of ciliated cells, is likely to be a major pathogenic mechanism of gonococcal salpingitis and might mediate postsalpingitis infertility and ectopic pregnancy.

STUDY DESIGN

A metaanalysis was performed on studies from three research groups (two laboratories in the United States and one in the United Kingdom, using identical techniques for quantifying the PPCA, TNF-alpha, or both.

RESULTS

There was a close and statistically significant correlation between the TNF-alpha mucosal tissue concentration and the proportion of ciliated cells lost from the mucosa as measured by the PPCA (r = 0.95, p < 0.001). Therefore, as the mucosal tissue concentration of endogenous TNF-alpha increased, the loss of ciliated cells from the epithelium increased proportionately.

CONCLUSIONS

During gonococcal infection of human fallopian tube mucosa in organ culture, the mucosal tissue concentration of TNF-alpha can be used to predict the PPCA, and therefore, the extent of mucosal damage. This finding should facilitate studies of the molecular pathogenesis of infectious diseases involving human genital mucosa. Further, the close correlation of mucosal TNF-alpha concentration with genital mucosal damage, evaluated by the PPCA, supports the hypothesis that induction of the proinflammatory cytokine, TNF-alpha, by gonococcal infection, with resultant inflammation and sloughing of ciliated cells, is an important pathogenic mechanism of gonococcal salpingitis and may mediate postsalpingitis infertility and ectopic pregnancy as well.

Long-term morbidity from Pope Ear Wicks

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In-vitro activity of sanfetrinem against isolates of Streptococcus pneumoniae and Staphylococcus aureus

The activity of sanfetrinem (previously GV104326), was assessed against 168 isolates of Streptococcus pneumoniae and 90 isolates of Staphylococcus aureus. These isolates included a range of serotypes or phage types, and varied in their susceptibility to other antibiotics. Sanfetrinem exhibited good anti-pneumococcal activity, with MIC90s of < or = 0.007 mg/L and 0.5 mg/L for penicillin-susceptible and penicillin-resistant isolates, respectively. Sanfetrinem was also active against methicillin-susceptible staphylococci (MIC90 = 0.06 mg/L). However, the MICs of sanfetrinem for isolates with methicillin MICs of 8-16 mg/L and > or = 32 mg/L were 0.25-1 mg/L and 8->32 mg/L, respectively.

Evaluation of disc diffusion and Etest for determining the susceptibility of Staphylococcus aureus to mupirocin

The susceptibilities to mupirocin of 102 selected clinical isolates of Staphylococcus aureus and of control strain S. aureus NCTC 6571 were determined by disc diffusion (using discs containing 5, 15, 25, 30, 50 and 200 microg of mupirocin) and Etest and the results were compared with MICs determined using an agar incorporation method. On the basis of agar incorporation MICs, 42 isolates were sensitive to mupirocin (MIC < or = 4 mg/L), 39 showed low-level resistance (MICs = 8-128 mg/L) and 22 were highly resistant (MICs > or = 256 mg/L) and contained the mupA resistance gene. Using Stokes' criteria, none of the discs used gave major errors (sensitive isolates classified as highly resistant) or very major errors (highly resistant isolates classified as sensitive) in assigning a category of susceptibility, but minor errors (a difference of one category) were noted with all strengths. The best correlation with agar incorporation MIC was obtained with 25 microg mupirocin discs, which classified correctly 98 (95%) isolates, while worse correlations were noted with 5 microg and 200 microg discs which are the only types currently available commercially, for which there were 47 and 30 minor errors, respectively. The MICs found by Etest were the same as, or lower than, those determined by agar incorporation. Etests classified correctly all 42 mupirocin-sensitive isolates, 19 (49%) low-level resistant isolates and 16 (73%) highly resistant isolates. Two isolates that contained the mupA gene and showed agar incorporation MICs of 256 mg/L and 512 mg/L were not classified as highly resistant by any of the diffusion methods used. Agar incorporation MIC determination, possibly supported by detection of the mupA gene, offers the most effective means of identifying high-level mupirocin resistance in S. aureus, although the Etest also proved to be reproducible. However, we conclude that 25 microg discs warrant further evaluation for possible use in clinical laboratories, as they appear to be more reliable than the discs currently available.

Antibiotic resistance among clinically important gram-positive bacteria in the UK

The resistance of bacteria to antibiotics, particularly those used for first-line therapy, is an increasing cause for concern. In the UK, the prevalence of resistance to methicillin and mupirocin in Staphylococcus aureus, and to penicillin and macrolides in Streptococcus pneumoniae, appear to be increasing. There has also been an increase in the number of hospitals where glycopeptide-resistant enterococci are known to have been isolated. The increases in methicillin-resistant S. aureus and glycopeptide-resistant enterococci are due, in part, to the inter-hospital spread of epidemic strains. Although new quinolones and streptogramins with activity against Gram-positive bacteria (including strains resistant to currently available agents) are under development, there is no reason to believe that resistance to these agents will not emerge. The control of resistance in Gram-positive bacteria will require a multi-faceted approach, including continued and improved surveillance, a reduction in the unnecessary use of antibiotics, and the application of other strategies such as vaccination.