Enzymes, Manganese, or Iron? Drivers of Oxidative Organic Matter Decomposition in Soils

Oxidative decomposition of soil organic matter determines the proportion of carbon that is either stored or emitted to the atmosphere as CO₂. Full conversion of organic matter to CO₂ requires oxidative mechanisms that depolymerize complex molecules into smaller, soluble monomers that can be respired by microbes. Current models attribute oxidative depolymerization largely to the activity of extracellular enzymes. Here we show that reactive manganese (Mn) and iron (Fe) intermediates, rather than other measured soil characteristics, best predict oxidative activity in temperate forest soils. Combining bioassays, spectroscopy, and wet-chemical analysis, we found that oxidative activity in surface litters was most significantly correlated to the abundance of reactive Mn(III) species. In contrast, oxidative activity in underlying mineral soils was most significantly correlated to the abundance of reactive Fe(II/III) species. Positive controls showed that both Mn(III) and Fe(II/III) species are equally potent in generating oxidative activity, but imply conventional bioassays have a systematic bias toward Fe. Combined, our results highlight the coupled biotic-abiotic nature of oxidative mechanisms, with Mn-mediated oxidation dominating within Mn-rich organic soils and Fe-mediated oxidation dominating Fe-rich mineral soils. These findings suggest microbes rely on different oxidative strategies depending on the relative availability of Fe and Mn in a given soil environment.

Collateral damage: the impact on outcomes from cancer surgery of the COVID-19 pandemic

BACKGROUND

Cancer diagnostics and surgery have been disrupted by the response of health care services to the coronavirus disease 2019 (COVID-19) pandemic. Progression of cancers during delay will impact on patients' long-term survival.

PATIENTS AND METHODS

We generated per-day hazard ratios of cancer progression from observational studies and applied these to age-specific, stage-specific cancer survival for England 2013-2017. We modelled per-patient delay of 3 and 6 months and periods of disruption of 1 and 2 years. Using health care resource costing, we contextualise attributable lives saved and life-years gained (LYGs) from cancer surgery to equivalent volumes of COVID-19 hospitalisations.

RESULTS

Per year, 94 912 resections for major cancers result in 80 406 long-term survivors and 1 717 051 LYGs. Per-patient delay of 3/6 months would cause attributable death of 4755/10 760 of these individuals with loss of 92 214/208 275 life-years, respectively. For cancer surgery, average LYGs per patient are 18.1 under standard conditions and 17.1/15.9 with a delay of 3/6 months (an average loss of 0.97/2.19 LYGs per patient), respectively. Taking into account health care resource units (HCRUs), surgery results on average per patient in 2.25 resource-adjusted life-years gained (RALYGs) under standard conditions and 2.12/1.97 RALYGs following delay of 3/6 months. For 94 912 hospital COVID-19 admissions, there are 482 022 LYGs requiring 1 052 949 HCRUs. Hospitalisation of community-acquired COVID-19 patients yields on average per patient 5.08 LYG and 0.46 RALYGs.

CONCLUSIONS

Modest delays in surgery for cancer incur significant impact on survival. Delay of 3/6 months in surgery for incident cancers would mitigate 19%/43% of LYGs, respectively, by hospitalisation of an equivalent volume of admissions for community-acquired COVID-19. This rises to 26%/59%, respectively, when considering RALYGs. To avoid a downstream public health crisis of avoidable cancer deaths, cancer diagnostic and surgical pathways must be maintained at normal throughput, with rapid attention to any backlog already accrued.

Challenges in the diagnosis of leptospirosis outwith endemic settings: a Scottish single centre experience

Background Leptospirosis is a zoonotic infection occurring worldwide but endemic in tropical countries. This study describes diagnostic testing for leptospirosis at our institution in Scotland over a 10-year period. Method We identified patients with blood samples referred to the Public Health England reference laboratory for leptospirosis testing between 2006 and 2016. Results A total of 480 samples were sent for IgM ELISA testing with 26 positive results from 14 patients. Two patients met criteria for 'confirmed' leptospirosis (microscopic agglutination test > 1:320 in one case and a positive PCR in the other) and the remaining 12 were 'probable' on the basis of IgM ELISA positivity, though 9 did not have microscopic agglutination testing performed. Nine infections were imported, mostly from Asia and with a history of fresh water exposure. Three co-infections (respiratory syncytial virus, influenza B and Campylobacter sp.) were identified. Conclusions Practical issues with microscopic agglutination testing (insufficient blood sent to reference laboratory) and PCR (travellers returning > 7 days after illness onset) represent challenges to the laboratory confirmation of a clinical diagnosis of leptospirosis. Co-infection and infectious/auto-immune causes of false positive serology should be evaluated.

Abstract P1-08-01: Withdrawn

This abstract was withdrawn by the authors.

Citation Format: Schoemaker MJ, Nichols HB, Wright LB, Brook MN, Jones ME, O'Brien KM, Adami H-O, Baglietto L, Bernstein L, Bertrand KA, Boutron-Ruault M-C, Chen Y, Connor AE, Dorronsoro M, Dossus L, Eliassen AH, Giles GG, Gram IT, Hankinson SE, Kaaks R, Key TJ, Kirsh VA, Kitahara CM, Koh W-P, Larsson SC, Linet MS, Ma H, Masala G, Merritt MA, Milne RL, Overvad K, Ozasa K, Palmer JR, Riboli E, Rohan TE, Sadakane A, Sund M, Tamimi RM, Trichopoulou A, Ursin G, Van Gils CH, Visvanathan K, Weiderpass E, Willett WC, Wolk A, Yuan J-M, Zeleniuch-Jacquotte A, Sandler DP, Swerdlow AJ. Withdrawn [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-08-01.

Manganese-Driven Carbon Oxidation at Oxic-Anoxic Interfaces

The formation of reactive manganese (Mn) species is emerging as a key regulator of carbon oxidation rates, and thus CO₂ emissions, in soils and sediments. Many subsurface environments are characterized by steep oxygen gradients, forming oxic-anoxic interfaces that enable rapid redox cycling of Mn. Here, we examined the impact of Mn(II)_aq oxidation along oxic-anoxic interfaces on carbon oxidation in soils using laboratory-based diffusion reactors. A combination of cyclic voltammetry, X-ray absorption spectroscopy, and X-ray microprobe imaging revealed a tight coupling between Mn(II)_aq oxidation and carbon oxidation at the oxic-anoxic interface. Specifically, zones of Mn(II)_aq oxidation across the oxic-anoxic transition also exhibited the greatest lignin oxidation potential, carbon solubilization, and oxidation. Microprobe imaging further revealed that the generation of Mn(III)-dominated precipitates coincided with carbon oxidation. Combined, our findings demonstrate that biotic Mn(II)_aq oxidation, specifically the formation of Mn(III) species, contributes to carbon oxidation along oxic-anoxic interfaces in soils and sediments. Our results suggest that we should regard carbon oxidation not merely as a function of molecular composition, which insufficiently predicts rates, but in relation to microenvironments favoring the formation of critically important oxidants such as Mn(III).

Electron transport and room temperature single-electron charging in 10 nm scale PtC nanostructures formed by electron beam induced deposition

Nanostructures of platinum-carbon nanocomposite material have been formed by electron-beam induced deposition. These consist of nanodots and nanowires with a minimum size ∼20 nm, integrated within ∼100 nm nanogap n-type silicon-on-insulator transistor structures. The nanodot transistors use ∼20 nm Pt/C nanodots, tunnel-coupled to Pt/C nanowire electrodes, bridging the Si nanogaps. Room-temperature single-electron transistor operation has been measured, and single-electron current oscillations and 'Coulomb diamonds' observed. In nanowire transistors, the temperature dependence from 290 to 8 K suggests that the current is a combination of thermally activated and tunnelling transport of carriers across potential barriers along the current path, and that the Pt/C is p-type at low temperature.

Oxidative Uranium Release from Anoxic Sediments under Diffusion-Limited Conditions

Uranium (U) contamination occurs as a result of mining and ore processing; often in alluvial aquifers that contain organic-rich, reduced sediments that accumulate tetravalent U, U(IV). Uranium(IV) is sparingly soluble, but may be mobilized upon exposure to nitrate (NO₃^-) and oxygen (O₂), which become elevated in groundwater due to seasonal fluctuations in the water table. The extent to which oxidative U mobilization can occur depends upon the transport properties of the sediments, the rate of U(IV) oxidation, and the availability of inorganic reductants and organic electron donors that consume oxidants. We investigated the processes governing U release upon exposure of reduced sediments to artificial groundwater containing O₂ or NO₃^- under diffusion-limited conditions. Little U was mobilized during the 85-day reaction, despite rapid diffusion of groundwater within the sediments and the presence of nonuraninite U(IV) species. The production of ferrous iron and sulfide in conjunction with rapid oxidant consumption suggested that the sediments harbored large concentrations of bioavailable organic carbon that fueled anaerobic microbial respiration and stabilized U(IV). Our results suggest that seasonal influxes of O₂ and NO₃^- may cause only localized mobilization of U without leading to export of U from the reducing sediments when ample organic carbon is present.

Combined effects of endogenous sex hormone levels and mammographic density on postmenopausal breast cancer risk: results from the Breakthrough Generations Study

BACKGROUND

Mammographic density and sex hormone levels are strong risk factors for breast cancer, but it is unclear whether they represent the same aetiological entity or are independent risk factors.

METHODS

Within the Breakthrough Generations Study cohort, we conducted a case-control study of 265 postmenopausal breast cancer cases and 343 controls with prediagnostic mammograms and blood samples. Plasma was assayed for oestradiol, testosterone and sex hormone-binding globulin (SHBG) concentrations and mammographic density assessed by Cumulus.

RESULTS

Oestradiol and testosterone were negatively and SHBG positively associated with percentage density and absolute dense area, but after adjusting for body mass index the associations remained significant only for SHBG. Breast cancer risk was independently and significantly positively associated with percentage density (P=0.002), oestradiol (P=0.002) and testosterone (P=0.007) levels. Women in the highest tertile of both density and sex hormone level were at greatest risk, with an odds ratio of 7.81 (95% confidence interval (CI): 2.89-21.1) for oestradiol and 4.57 (95% CI: 1.75-11.9) for testosterone and high density compared with those who were in the lowest tertiles. The cumulative risk of breast cancer in the highest oestradiol and density tertiles, representing 8% of controls, was estimated as 12.8% at ages 50-69 years and 19.4% at ages 20-79 years, and in the lowest tertiles was 1.7% and 4.3%, respectively. Associations of breast cancer risk with tertiles of mammographic dense area were less strong than for percentage density.

CONCLUSIONS

Endogenous sex hormone levels and mammographic density are independent risk factors for postmenopausal breast cancer, which in combination can identify women who might benefit from increased frequency of screening and chemoprophylaxis.

Breast cancer risk following Hodgkin lymphoma radiotherapy in relation to menstrual and reproductive factors

BACKGROUND

Women treated with supradiaphragmatic radiotherapy (sRT) for Hodgkin lymphoma (HL) at young ages have a substantially increased breast cancer risk. Little is known about how menarcheal and reproductive factors modify this risk.

METHODS

We examined the effects of menarcheal age, pregnancy, and menopausal age on breast cancer risk following sRT in case-control data from questionnaires completed by 2497 women from a cohort of 5002 treated with sRT for HL at ages <36 during 1956-2003.

RESULTS

Two-hundred and sixty women had been diagnosed with breast cancer. Breast cancer risk was significantly increased in patients treated within 6 months of menarche (odds ratio (OR) 5.52, 95% confidence interval (CI) (1.97-15.46)), and increased significantly with proximity of sRT to menarche (Ptrend<0.001). It was greatest when sRT was close to a late menarche, but based on small numbers and needing reexamination elsewhere. Risk was not significantly affected by full-term pregnancies before or after treatment. Risk was significantly reduced by early menopause (OR 0.55, 95% CI (0.35-0.85)), and increased with number of premenopausal years after treatment (Ptrend=0.003).

CONCLUSION

In summary, this paper shows for the first time that sRT close to menarche substantially increases breast cancer risk. Careful consideration should be given to follow-up of these women, and to measures that might reduce their future breast cancer risk.

Does an interferon-gamma release assay change practice in possible latent tuberculosis?

BACKGROUND AND AIMS

Suspected latent tuberculosis infection (LTBI) is a common reason for referral to TB clinics. Interferon-gamma release assays (IGRAs) are more specific than tuberculin skin tests (TSTs) for diagnosing LTBI. The aim of this study is to determine if IGRA changes practice in the management of cases referred to a TB clinic for possible LTBI.

DESIGN AND METHODS

A prospective study was performed over 29 months. All adult patients who had TST, CXR & IGRA were included. The original decision regarding TB chemoprophylaxis was made by TB team consensus, based on clinical history and TST. Cases were then analysed with the addition of IGRA to determine if this had altered management. An independent physician subsequently reviewed the cases.

RESULTS

Of 204 patients studied, 68 were immunocompromised. 120 patients had positive TSTs. Of these, 36 (30%) had a positive QFT and 84 (70%) had a negative QFT. Practice changed in 78 (65%) cases with positive TST, all avoiding TB chemoprophylaxis due to QFT. Of the immunocompromised patients, 17 (25%) underwent change of practice. No cases of active TB have developed.

CONCLUSION

This study demonstrates a significant change of clinical practice due to IGRA use. Our findings support the NICE 2011 recommendations.

Correlating the deep inferior epigastric artery branching pattern with type of abdominal free flap performed in a series of 145 breast reconstruction patients

INTRODUCTION

The deep inferior epigastric perforator (DIEP) flap is currently viewed as the gold standard in autologous breast reconstruction. We studied three-dimensional computed tomography angiography (CTA) in 145 patients undergoing free abdominal flap breast reconstruction to try to correlate deep inferior epigastric artery (DIEA) branching pattern with the type of flap performed and patient outcome. Today, reconstructive breast surgeons have become more experienced in raising DIEP flaps and operative times are becoming more acceptable. However, there remains significant interest in finding ways to aid this challenging dissection.

METHODS

We retrospectively evaluated consecutive patients between January 2007 and August 2008. CTAs were analysed using the Moon and Taylor (1988) classification of the DIEA branching pattern. Data gathered included pre-operative morbidity, type of abdominal wall free flap performed, length of operation, length of stay and complications.

RESULTS

Some 150 breast reconstructions were performed in 145 patients. There were 67 DIEP flaps, 69 MS-2 transverse rectus abdominis myocutaneous (TRAM) flaps and 14 MS-1 TRAM flaps (where MS-1 spares the lateral muscle and MS-2 spares both lateral and medial segments). Proportionally more DIEP flaps were performed in patients with a type 2 branching pattern. There was one flap loss (0.67%).

CONCLUSIONS

In this large CTA series, we found a type 1 (single artery) DIEA pattern most frequently, in contrast to the predominance of the type 2 bifurcating pattern observed previously. The higher proportion of DIEP flaps performed in the type 2 pattern patients is consistent with the documented shorter intramuscular course in this group. We have found CTA useful for faster selection of the best hemiabdomen for dissection and flap loss rates in our unit have reduced from 1.5% to 0.67%.

Alcohol consumption and driving intentions amongst hotel patrons

To examine the extent to which hotel patrons drink in excess of current health recommendations, and to identify risk factors for excessive drinking, hotel patrons were invited to participate in a survey of social drinking, which included a free breath test. Patrons were approached at 15 min. intervals, and 1000 subjects were studied. Amongst this group of hotel patrons interviewed, 1 in 2 had consumed alcohol in excess of the daily limit recommended by the National Health & Medical Research Council. One in 10 intending drivers had a BAC over the legal limit. Excessive drinking and drink driving appear to be prevalent amongst hotel patrons, and hotels should be targets for interventions designed to reduce these problems. For example, the National Guidelines for the Responsible Serving of Alcohol should be more widely practised.

The Breakthrough Generations Study: design of a long-term UK cohort study to investigate breast cancer aetiology

BACKGROUND

The rationale, design, recruitment and follow-up methods are described for the Breakthrough Generations Study, a UK cohort study started in 2003, targeted at investigation of breast cancer aetiology.

METHODS

Cohort members have been recruited by a participant referral method intended to assemble economically a large general population cohort from whom detailed questionnaire information and blood samples can be obtained repeatedly over decades, with high completeness of follow-up and inclusion of large numbers of related individuals. 'First-generation' recruits were women contacted directly, or who volunteered directly, to join the study. They nominated female friends and family, whom we contacted, and those who joined ('second generation') nominated others, reiterated for up to 28 generations.

RESULTS

The method has successfully been used during 2003-2011 to recruit 112,049 motivated participants with a broad geographic and socioeconomic distribution, aged 16-102 years, who have completed detailed questionnaires; 92% of the participants gave blood samples at recruitment. When eligible, 2½ years after recruitment, >98% completed the first follow-up questionnaire. Thirty percent are first-degree relatives of other study members.

CONCLUSION

The 'generational' recruitment method has enabled recruitment of a large cohort who appear to have the commitment to enable long-term continuing data and sample collection, to investigate the effects of changing endogenous and exogenous factors on cancer risk.

Evidence that disease-induced population decline changes genetic structure and alters dispersal patterns in the Tasmanian devil

Infectious disease has been shown to be a major cause of population declines in wild animals. However, there remains little empirical evidence on the genetic consequences of disease-mediated population declines, or how such perturbations might affect demographic processes such as dispersal. Devil facial tumour disease (DFTD) has resulted in the rapid decline of the Tasmanian devil, Sarcophilus harrisii, and threatens to cause extinction. Using 10 microsatellite DNA markers, we compared genetic diversity and structure before and after DFTD outbreaks in three Tasmanian devil populations to assess the genetic consequences of disease-induced population decline. We also used both genetic and demographic data to investigate dispersal patterns in Tasmanian devils along the east coast of Tasmania. We observed a significant increase in inbreeding (F(IS) pre/post-disease -0.030/0.012, P<0.05; relatedness pre/post-disease 0.011/0.038, P=0.06) in devil populations after just 2-3 generations of disease arrival, but no detectable change in genetic diversity. Furthermore, although there was no subdivision apparent among pre-disease populations (θ=0.005, 95% confidence interval (CI) -0.003 to 0.017), we found significant genetic differentiation among populations post-disease (θ=0.020, 0.010-0.027), apparently driven by a combination of selection and altered dispersal patterns of females in disease-affected populations. We also show that dispersal is male-biased in devils and that dispersal distances follow a typical leptokurtic distribution. Our results show that disease can result in genetic and demographic changes in host populations over few generations and short time scales. Ongoing management of Tasmanian devils must now attempt to maintain genetic variability in this species through actions designed to reverse the detrimental effects of inbreeding and subdivision in disease-affected populations.

Determinants of age at menarche in the UK: analyses from the Breakthrough Generations Study

BACKGROUND

Early menarche increases breast cancer risk but, aside from weight, information on its determinants is limited.

METHODS

Age at menarche data were collected retrospectively by questionnaire from 81,606 women aged 16-98, resident in the UK and participating in the Breakthrough Generations Study.

RESULTS

Menarche occurred earlier in women who had a low birthweight (P(trend)<0.001), were singletons (P<0.001), had prenatal exposure to pre-eclampsia (P<0.001) or maternal smoking (P=0.01), were not breastfed (P(trend)=0.03), were non-white (P<0.001), were heavy (P(trend)<0.001) or tall (P(trend)<0.001) compared with their peers at age 7 and exercised little as a child (P(trend)<0.001). Menarcheal age increased with number of siblings (P<0.001) independently of birth order, and had an inverse association with birth order after adjustment for sibship size (P<0.001). In a multivariate model, birthweight, ethnicity, weight, height, exercise, sibship size and birth order remained significant, and maternal age at birth became significant (positive association, P<0.001).

CONCLUSION

Age at menarche was influenced by both pre- and post-natal factors, and these factors may affect breast cancer risk through this route.

Trends in weights, heights, BMI and comparison of their differences in urban and rural areas for Iranian children and adolescents 2-18-year-old between 1990-1991 and 1999

BACKGROUND

Secular trends in height and weight are interesting because in middle- and low-income countries they are a marker for changes in population health. The present study aims to evaluate the secular trend in height and weight and body mass index (BMI) of Iranian children and adolescents aged 2-18 years old between 1990-1991 and 1999 and compare the magnitude of urban-rural differences during this period for the first time in an Asian country.

METHODS

Data from two national health surveys in 1990-1991 and 1999, of 22,349 and 25,196 weight and height measures of Iranian children and adolescents were used to study the trend and compare its difference in urban and rural children. Logarithmic transformation of weight, height and BMI was modelled as a polynomial in age for urban and rural boys and girls in each survey separately. The trend in urban and rural growth indexes (weight, height and BMI) and also the comparisons of urban-rural differences between two national surveys were tested in logarithmic scale using a weighted form of Z statistic for comparison of two means adjusted for age groups.

RESULTS

Urban and rural boys and girls became taller and heavier (P≤ 0.02) with no change of BMI (P > 0.05) during the period. There was not any significant difference between the magnitudes of urban-rural difference between two surveys (P≥ 0.61).

CONCLUSION

Although generally positive weight and height trend was observed among urban and rural residents, the magnitude of their differences was not changed.

A clinical trial assessing the safety and efficacy of the CB1R inverse agonist taranabant in obese and overweight patients: low-dose study

OBJECTIVE

To evaluate the weight loss efficacy, safety and tolerability of taranabant, a CB1R inverse agonist, in obese and overweight patients.

DESIGN

Multicenter, double-blind, randomized, placebo-controlled study.

SUBJECTS

Patients >or=18 years old, BMI 27-43 kg m(-2), were randomized to placebo (n=209) or taranabant 0.5 mg (n=207), 1 mg (n=208) or 2 mg given orally once daily (n=417) for 52 weeks.

MEASUREMENTS

Key efficacy measurements included body weight (BW), waist circumference (WC), lipid endpoints and glycemic endpoints.

RESULTS

Based on a last observation carried forward analysis of the all-patients-treated population, mean change in BW for taranabant 0.5, 1, and 2 mg and placebo was -5.4, -5.3, -6.7 and -1.7 kg, respectively (P<0.001 for all doses vs placebo). The proportions of patients who lost at least 5 and 10% of their baseline BW at week 52 were significantly higher for all taranabant doses vs placebo (P<0.001 for all doses). Reductions in WC, percentage of body fat, and triglycerides were significant for taranabant 2 mg and in triglycerides for taranabant 1 mg vs placebo. There was no effect of taranabant vs placebo on other lipid or glucose-related endpoints. Incidences of adverse experiences classified in the gastrointestinal (diarrhea and nausea), nervous system (dizziness/dizziness postural), psychiatric-related (irritability and anger/aggression) and vascular (flushing/hot flush) organ systems were higher and statistically significant in the taranabant 2-mg group compared with the placebo group. Irritability was higher and statistically significant in all taranabant groups compared with the placebo group.

CONCLUSION

All three doses of taranabant-induced clinically meaningful and statistically significant weight loss. Incidences of adverse experiences in organ systems known to express CB1R were higher in taranabant groups.

Second trimester fetal abnormality scans: do women know the reasons why they are done?

A 10 point questionnaire was given to 239 women attending for second trimester fetal abnormality ultrasound scans to explore their level of knowledge about the nature, purpose and limitations of the procedure. Questions were included about the conditions which could or could not be diagnosed, and about the accuracy and sensitivity of the procedure. Demographic data was also recorded. Two hundred and thirty-five forms were correctly completed. The percentage of women returning correct answers ranged from 58.8% to 100% and response rate was correlated with years of full time education in some questions. The results suggest that patients perceive the scan as a chance to see their baby and that many do not fully appreciate either the purpose or the limitations of fetal anomaly scanning. This may complicate the post-test counselling required if an abnormality is detected.

Promotion of responsible drinking in hotels

This study reports on an intervention programme to promote responsible drinking in hotels. The licensees of eight hotels agreed to participate in a trial of measures designed to assist patrons to avoid drink-driving, and seven other hotels were used as controls. The interventions acceptable to licensees comprised commercial-quality promotional material with the theme "0.05 Know Your Limits", and a breath analysis machine and poster on its use. Patrons leaving the hotels on Thursday, Friday and Saturday nights were interviewed and breath-tested. Although the intervention material had been seen by one-third of patrons in the intervention hotels, there was no significant difference between them and control hotel patrons in either median BAC or the proportion who were going to drive with BAC over the legal limit. There was poor compliance by hotels with the intervention procedures, indicating that a major impediment to the implementation and evaluation of programmes to promote responsible drinking is a lack of motivation by many licensees, despite support by some licensees and the Australian Hotels Association.

Trends in hotel patronage and drink driving in Hobart, Tasmania

From 1990 to 1991 in the Hobart region there was a marked fall in both hotel patronage and the proportion of patrons subsequently driving with their blood alcohol concentration above the legal limit. This was associated with smaller falls in the number of drink drivers charged and alcohol-related road accidents, which continued in the following year. It appears that the pattern of drinking and driving is changing, presumably in response to random breath testing and tougher penalties for offences.

In-vitro profile of a new beta-lactam, ceftobiprole, with activity against methicillin-resistant Staphylococcus aureus

Ceftobiprole is a novel, broad-spectrum cephalosporin with in-vitro activity against common Gram-positive and Gram-negative organisms. It forms a stable inhibitory complex with Staphylococcus aureus penicillin-binding protein (PBP) 2' (2a), resulting in enhanced activity against methicillin-resistant S. aureus (MRSA). In recent studies of methicillin-susceptible S. aureus, the ceftobiprole MIC(90) value was most frequently < or =1.0 mg/L (MIC range < or =0.25-1.0 mg/L). For MRSA, MIC(90) values were generally 2.0 mg/L (MIC range < or =0.06-4.0 mg/L). MICs for all streptococcal species, except penicillin-resistant Streptococcus viridans but including penicillin-resistant Streptococcus pneumoniae, ranged from < or =0.008 to 2.0 mg/L. Ceftobiprole is active against Enterococcus faecalis (MIC(90) = 4 mg/L), but not generally active against Enterococcus faecium (MIC(90) > 16 mg/L). Ceftobiprole displayed bactericidal activity against Gram-negative pathogens comparable to that of cefepime, ceftazidime or piperacillin-tazobactam in early studies. However, recent data show activity against Pseudomonas aeruginosa similar to that of cefepime but less than that of ceftazidime. Ceftobiprole, like cefepime, is stable in the presence of most class A non-extended spectrum beta-lactamases and inducible class C beta-lactamases. Ceftobiprole is a poor inducer of AmpC beta-lactamase and a poor substrate for hydrolysis by AmpC beta-lactamase. Studies of ceftobiprole in several animal models have demonstrated potent in-vivo efficacy against infections caused by MRSA, including strains intermediately resistant to vancomycin. It was also efficacious in murine infections caused by Gram-negative bacteria with MIC values < or =2 mg/L. The broad spectrum of activity demonstrated by ceftobiprole in vitro and in vivo suggests that it may have potential for empirical treatment of suspected Gram-negative and Gram-positive infections, including those caused by MRSA.

Of mice and men: the many guises of estrogens

Models of estrogen insufficiency have revealed new and unexpected roles for estrogens in males as well as females. These models include natural mutations in the aromatase gene in humans, as well as mouse knock-outs of aromatase and the estrogen receptors, and one man with a mutation in the ERa gene. These mutations, both natural and experimental, have revealed that estrogen deficiency results in a spectrum of symptoms. These include loss of fertility and libido in both males and females; loss of bone in both males and females; a cardiovascular and cerebrovascular phenotype; development of a metabolic syndrome in both males and females, with truncal adiposity and male-specific hepatic steatosis. Most of these symptoms can be reversed or attenuated by estradiol therapy. Thus estrogen is involved in the maintenance of general physiological homeostasis in both sexes.

Measuring bidirectional mutation

The estimation of mutation rates is usually based on a model in which mutations are rare independent Poisson events. Back-mutation of mutants, an even rarer event, is ignored. In the hypermutating B cells of the immune system, mutation between phenotypes exhibiting, vs. not exhibiting, surface immunoglobulin is common in both directions. We develop three strategies for the estimation of mutation rates under circumstances such as these, where mutation rates in both directions are estimated simultaneously. Our model for the growth of a cell culture departs from the classical assumption of cell division as a memoryless (Poisson) event; we model cell division as giving rise to sequential generations of cells. On this basis, a Monte-Carlo simulation is developed. We develop also a numerical approach to calculating the probability distribution for the proportion of mutants in each culture as a function of forward- and backward-mutation rates. Although both approaches are too computationally intensive for routine laboratory use, they provide the insight necessary to develop and evaluate a third, 'hand-calculator' approach to extracting mutation rate estimators from experiments of this type.

The use of a proximally based posterior interosseous adipofascial flap to prevent recurrence of synostosis of the elbow joint and forearm

We report on four children in whom a proximally based, posterior interosseous artery adipofascial flap was used as an adjunct to surgical resection of synostoses of the forearm and elbow. Three traumatic radio-ulnar and one congenital humero-radial synostoses were treated. The postoperative pronation to supination arc of motion was excellent in all of the traumatic cases and fair in the congenital case.

Ovarian cancer risk in premenopausal and perimenopausal women treated with Tamoxifen: a case-control study

As tamoxifen stimulates ovarian steroidogenesis in premenopausal women, induces ovulation and increases the incidence of benign ovarian cysts, there has been concern that it might also increase ovarian cancer risk in women treated premenopausally. In a national case–control study in Britain, treatment histories were collected for 158 cases of ovarian cancer after breast cancer diagnosed at ages under 55 years and 464 controls who had breast cancer at these ages without subsequent ovarian cancer. Risk of ovarian cancer was not raised for women overall who had taken tamoxifen (odds ratio (OR)=0.9, 95% confidence interval (CI) 0.6–1.3) or for those treated when premenopausal (OR=1.0, 95% CI 0.6–1.6) or perimenopausal (OR=0.7, 95% CI 0.2–2.4). There was also no relation of risk to daily dose, duration or cumulative dose of tamoxifen, or time since last use. There was, however, a significantly raised risk in relation to non-hormonal chemotherapy. The results suggest that tamoxifen treatment of premenopausal or perimenopausal women does not materially affect ovarian cancer risk, but that non-hormonal chemotherapy might increase risk.

Geographically-based evaluation of multidrug resistance trends among Streptococcus pneumoniae in the USA: findings of the FAST surveillance initiative (2003–2004)

Surveillance initiatives to track Streptococcus pneumoniae resistance trends are important for understanding the current in vitro effectiveness of available antimicrobial agents. The antimicrobial susceptibility profiles of S. pneumoniae (n=1479 isolates) collected from 17 geographical areas across the USA (2003-2004) were analysed; 36.8% of isolates were resistant to one or more agents (24.4% were multidrug-resistant, i.e. resistant to two or more antimicrobial classes). Multidrug resistance involved resistance to beta-lactams, macrolides, tetracycline and trimethoprim/sulphamethoxazole, but rarely fluoroquinolones (>96% of multidrug-resistant isolates were fluoroquinolone-susceptible). Multidrug resistance rates were prominent regardless of the geographical region surveyed. As this trend continues, the empirical therapeutic options for S. pneumoniae infections will diminish and there will be an ongoing need to evaluate the effectiveness of potent fluoroquinolones such as gemifloxacin.

UK patients with primary Sjogren's syndrome are at increased risk from clinical depression

OBJECTIVE

This study was undertaken to assess the presence and degree of anxiety and depression in a group of UK patients with primary Sjögren's syndrome (1 degrees SS).

DESIGN

Cross-sectional.

SETTING

Department of Oral Medicine, Liverpool University Dental Hospital.

SUBJECTS

Eighty adult patients; 40 diagnosed with 1 degrees SS according to the revised European Criteria and 40 age/gender-matched controls with no history of chronic illness.

INTERVENTION

Hospital Anxiety and Depression Scale (HADS), a self-administered questionnaire designed to evaluate the presence and degree of anxiety and depression in a clinical setting.

MAIN OUTCOME MEASURES

Age, gender, Hospital Anxiety and Depression Scale (HADS).

RESULTS

Forty patients with 1degrees SS and 40/age/gender-matched controls completed the HADS. Scores for anxiety in both the 1 degrees SS and control groups showed no statistically significant difference. Patients with 1 degrees SS had statistically significant higher, mean HADS scores for depression than the controls. There was an increased prevalence of 'definite' clinical depression in the 1 degrees SS group.

CONCLUSION

Patients with 1 degrees SS appear to be at increased risk from clinical depression. Early recognition and appropriate intervention is therefore essential to reduce the negative impact of depression on the patient's quality of life and outcome of their disease.

Rates of antimicrobial resistance among common bacterial pathogens causing respiratory, blood, urine, and skin and soft tissue infections in pediatric patients

Antimicrobial resistance patterns among the principal bacterial pathogens from infections of the respiratory tract, blood, skin and soft tissue, and urinary tract of pediatric patients from the USA, Canada, Germany, France, and Italy were studied using the The Surveillance Network (TSN) database. Among Streptococcus pneumoniae isolates from respiratory tract infections, the prevalence of high-level penicillin resistance (MIC>/=2 microg/ml) ranged from 1.1 (Italy) to 36.2% (USA); erythromycin resistance was higher, ranging from 13.4 (Germany) to 63.8% (France). The prevalence of beta-lactamase-positive Haemophilus influenzae among isolates from lower respiratory tract infections ranged from <10 (Italy and Germany) to 38.4% (USA). Among isolates from blood and skin and soft tissue infections, the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) ranged from 7.2% (Canada and Germany) to 27.3% (Italy). The prevalence of Escherichia coli and Klebsiella pneumoniae with putative extended-spectrum beta-lactamases among isolates from blood, urinary tract, and skin and soft tissue infections ranged from 0 (Germany and France) to 29.6% (Italy). With the exception of pseudomonal infections or infections with MRSA, amoxicillin-clavulanate retained moderate activity, whilst ceftriaxone and cefepime were the most effective broad-spectrum injectable agents. Meropenem was the most effective agent against Pseudomonas aeruginosa with <5% resistance. Low levels of resistance, along with acceptable safety profiles and the availability of convenient oral formulations, continue to support the use of ceftriaxone, cefepime, amoxicillin-clavulanate, and meropenem as viable options for the treatment of infections in pediatric patients.

Antimicrobial susceptibility to levofloxacin and other antibacterial agents among common respiratory pathogens—a Brazilian perspective from the GLOBAL Surveillance Initiative 2001–2002

The GLOBAL (Global Landscape On Bactericidal Activity of Levofloxacin) Surveillance programme monitored antimicrobial susceptibility patterns of the key respiratory tract pathogens Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis collected in Brazil during 1997-1998, 1999-2000 and 2001-2002. Penicillin and azithromycin resistance among S. pneumoniae strains increased from 1997-1998, reaching 7.9% and 9.5%, respectively, in 2001-2002. Although decreasing by 4.9% since the previous study, trimethoprim-sulphamethoxazole resistance remained high at 33.7%. Concurrent resistance to penicillin, azithromycin and trimethoprim-sulphamethoxazole was seen in 2.9% of the S. pneumoniae isolates collected. Levofloxacin remained extremely active against S. pneumoniae, with 0.3% resistance reported in 1997-1998 and 0% resistance in 1999-2000 and 2001-2002. beta-Lactamase production in H. influenzae was > 10% in all three studies, with correspondingly high rates of ampicillin resistance. Trimethoprim-sulphamethoxazole was the least active agent tested against H. influenzae, with resistance rates of > 40% recorded in all three studies. All H. influenzae isolates were susceptible to cefuroxime, ceftriaxone, azithromycin and levofloxacin. Of the M. catarrhalis isolates, 98.0% in 1997-1998, 98.0% in 1999-2000 and 81.8% in 2001-2002 were beta-lactamase-positive. The continued high prevalence of antimicrobial resistance in Brazil underscores the importance of current surveillance initiatives. Levofloxacin, a fluoroquinolone prescribed widely for respiratory tract infections, continued to show potent activity against key respiratory pathogens.

Creutzfeldt-Jakob disease in United Kingdom patients treated with human pituitary growth hormone

OBJECTIVE

To investigate risk factors for Creutzfeldt-Jakob disease (CJD) in patients in the United Kingdom treated with human pituitary growth hormone (hGH).

METHODS

Incidence rates of CJD, based on person-year denominators, were assessed in a cohort of 1,848 patients treated with hGH in the United Kingdom from 1959 through 1985 and followed to the end of 2000.

RESULTS

CJD developed in 38 patients. Risk of CJD was significantly increased by treatment with hGH prepared by the Wilhelmi method of extraction from human pituitaries. Risk was further raised if this treatment was administered at ages 8 to 10 years. The peak risk of CJD was estimated to occur 20 years after first exposure, and the estimated lifetime cumulative risk of CJD in Wilhelmi-treated patients was 4.5%.

CONCLUSIONS

Size-exclusion chromatography, used in non-Wilhelmi preparation methods, may prevent CJD infection. Susceptibility to CJD may vary with age, and susceptibility may be present in only a few percent of the population.

Antibiotic susceptibility of isolates of Bacillus anthracis, a bacterial pathogen with the potential to be used in biowarfare

Bacillus anthracis is a bacterial species that could be used in a bioterrorist attack. We tested a collection of isolates with a range of relevant antimicrobial compounds. All isolates tested were susceptible to ciprofloxacin and doxycycline. Penicillin and amoxicillin, with or without clavulanate, showed in vitro activity against all B. anthracis isolates. Ceftriaxone demonstrated lower-level in vitro activity compared to penicillin-related compounds against B. anthracis. In vitro data from this study are in keeping with available guidelines.

In vitro susceptibility of Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis: a European multicenter study during 2000-2001

OBJECTIVE

To assess the current (2001) activity of respiratory fluoroquinolones and comparator agents against respiratory pathogens isolated in European countries.

METHODS

During 2000-2001, we prospectively collected 1995 isolates of Haemophilus influenzae, 1870 isolates of Streptococcus pneumoniae and 649 isolates of Moraxella catarrhalis from hospital laboratories in France, Germany, Greece, Italy, Spain and the UK. National Committee for Clinical Laboratory Standards (NCCLS)-approved broth microdilution antimicrobial susceptibility testing methods and interpretive criteria were used throughout.

RESULTS

Of the S. pneumoniae isolates, 99.6% were susceptible to moxifloxacin, gatifloxacin and levofloxacin; the corresponding figure for H. influenzae was 100%. All M. catarrhalis isolates had moxifloxacin MICs </= 0.12 mg/L. For all three pathogens, fluoroquinolone susceptibility remained unchanged from the previous 1997-98 study. The incidence of penicillin non-susceptibility in the S. pneumoniae isolates tested remained similar to or higher than that recorded in previous studies: France, 165/291 (56.7%); Germany, 46/506 (9.1%); Greece, 20/55 (36.4%); Italy, 45/364 (12.4%); Spain, 146/268 (54.5%); and the UK, 26/386 (6.7%). Significant levels of resistance to oral compounds (cefuroxime, cefaclor, cefdinir, clarithromycin, azithromycin, tetracycline, and trimethoprim-sulfamethoxazole) were detected among S. pneumoniae isolates. beta-Lactamase production among H. influenzae isolates ranged from 6.2% to 33.1% per country, and ampicillin, clarithromycin or trimethoprim-sulfamethoxazole resistance were the most common phenotypes detected. beta-Lactamase production among M. catarrhalis isolates ranged from 94.1% to 100% per country.

CONCLUSIONS

With the exception of a few localized reports, resistance to moxifloxacin and other new fluoroquinolones in common respiratory pathogens is a rare occurrence, despite significant resistance to other compound classes. Surveillance will play a key role in tracking changes in fluoroquinolone susceptibility in European countries.

Antimicrobial susceptibility of 840 clinical isolates of Haemophilus influenzae collected in four European countries in 2000-2001

In 2000-2001, 840 clinical isolates of Haemophilus influenzae were collected from laboratories in France, Germany, Italy and Spain (210 isolates/country). Beta-Lactamase production among the isolates varied considerably by country, ranging from 8.1% in Germany to 34.8% in France. H. influenzae from patients <or=4 years old showed the highest prevalence of beta-lactamase production (23.2%), compared with isolates from patients aged 5-17 years (17.8%) and >or=18 years (16.5%). All isolates were susceptible to amoxicillin-clavulanate, ciprofloxacin and levofloxacin; 99.6% and 98.9% of isolates were susceptible to azithromycin and cefuroxime, respectively. Among the macrolides tested, azithromycin (MIC90, 2 mg/L) was eight-fold more potent than clarithromycin (MIC90, 16 mg/L) and roxithromycin (MIC90, 16 mg/L). Despite variations in beta-lactamase production between different countries, > 99% of all isolates were susceptible to amoxicillin-clavulanate, ciprofloxacin, levofloxacin, and azithromycin.

[Endemic heteroresistant glycopeptide intermediate Staphylcoccus aureus (hGISA) comprising unrelated clonal types and not associated with vancomycin therapy]

The detection of methicillin-resistant S. aureus (SA) (MRSA) refractory to glycopeptides is a serious clinical issue. The prevalence of hetero-resistant GISA (hGISA) strains at H. Maréchal Joffre, France is reported.858 non-repeat SA were isolated during 1999. 367 (43%) of these, from 257 patients, were MRSA (mean incidence 11.9/1000 admissions). All MSRA detected during 1999 were screened for vancomycin (VAN) resistance (BHI+4 mg/l VAN). Isolates recovered were retested using Etest strips (2 McFarland inoculum on BHI) and population analysis profile/area under the curve (PAP-AUC) analysis with hGISA SA Mu3 as a comparator. 58 selected strains were screened for teicoplanin resistance(TEI) using SFM recommended screen (2 McFarland inoculum on MH+5 mg/L TEI) and MIC (0.5 MF inoculum swabbed on MH agar) methods. 188 (51.3%) grew on VAN screen agar (6.1/1000 admissions). 58 strains (7.6%) possessed Etest VAN MIC > 8 mg/l all others being VAN < 8 mg/l. Of these 58 isolates, 10 were stably heterogeneously resistant to both VAN and teicoplanin (MIC > 8 mg/l). PAP-AUC showed 12 strains to have PAP-AUC ratios > 0.95 but < 1.5 (ie. hGISA, not GISA). All 7 isolates defined as hGISA by both Etest and PAP-AUC comprised 1 PFGE clone (< 3 bands difference). Additionally 2 distinct PFGE types were detected among the other 5 hGISA identified PAP-AUC. The 12 hGISAs, were derived from 12 patients with severe underlying disease. None were on glycopeptide therapy prior to hGISA isolation. This is the first report of endemic hGISA, comprising 3 clonal types. The isolation of hVISA seems not to be associated with patient-specific glycopeptide therapies.

Futile cycles revisited: a markov chain model of simultaneous glycolysis and gluconeogenesis

We have used a random walk model of glycolysis and gluconeogenesis to investigate the bioenergetic implications of considering the cell cytoplasm to be a uniform well-mixed compartment. Radiotracer studies conducted on hepatocytes harvested from fasted rats and incubated with 40 mM glucose and 10 mM lactate demonstrated simultaneous glycolysis and gluconeogenesis, with net glycolysis. Tracer introduced as glycerol was incorporated both into glucose (via gluconeogenesis) and into pyruvate (via glycolysis). The data allow us to place a lower bound on the energetic cost of futile cycles involving adenosine triphosphate (ATP) hydrolysis in the early phosphorylation steps of glycolysis. Applying the Markov Chain model for glucose undergoing metabolism to pyruvate, the expected number of ATP molecules hydrolysed is not less than 15 ATP molecules per glucose molecule. The data suggest that, in hepatocytes under the circumstances of this experiment, either glycolysis is a net consumer of ATP, or glycolysis and gluconeogenesis are compartmentalized to a greater extent than is generally supposed.

The road to ovulation: the role of oestrogens

Oestrogens have been known for many years to have a direct influence on folliculogenesis. Oestradiol-17beta (E2) and its analogues have both proliferative and differentiative effects on somatic cells of follicles. Nevertheless, definitive proof of an obligatory role for oestrogen in folliculogenesis and elucidation of the mechanisms subserving its different actions in follicular cells remains elusive. Several recent developments permit a re-examination of the roles and actions of E2 in the follicle. They are: (i) the discovery of a second form of the oestrogen receptor, ERbeta; (ii) the advent of genetically modified mice with deletions in the ERalpha (alphaERKO) ERbeta (BERKO) and the double ER deletions (alphabetaERKO); and (iii) a mouse model of oestrogen deficiency (ArKO) by targeted disruption of the cyp 19 gene encoding the aromatase enzyme. Recent information derived from these models is reviewed to re-assess the roles and actions of oestrogens in follicular dynamics and the phenotypic differentiation of ovarian somatic cells in the ovary. The data demonstrate that oestrogen is obligatory for normal folliculogenesis and that the phenotype of the ovarian somatic cells depends on the steroid milieu. The ArKO mouse provides a model to test the roles of the respective ERs in proliferation and differentiation using specific agonists and antagonists, and to study regulation of the differentiation of ovarian and testicular somatic cells.

The role of human-derived fibrin sealant in the reduction of postoperative flexor tendon adhesion formation in rabbits

This study assessed the role of a novel fibrin sealant (Vivostat in adhesion reduction after flexor tendon surgery. The deep flexor tendons of the 2nd and 4th digits of the left paw of 20 rabbits were exposed and a standard partial injury was performed on each. The rabbits were randomized to either immediate post-injury treatment with Vivostat or no treatment. In each case active movement of the 2nd digit was prevented while the 4th digit was allowed to move normally. The two groups were assessed at 14 days for adhesion formation with a tensiometer. The right paw acted as the unoperated control. Results showed that there was no significant difference in the force needed to remove the tendon from its sheath when comparing the two Vivostat((R))-treated groups to the unoperated controls. There was, however, a highly significant difference in this force between the non-Vivostat-treated groups and the unoperated controls. This suggests a beneficial effect of Vivostat in reducing post surgical tendon adhesion formation.

Ceftriaxone activity against Gram-positive and Gram-negative pathogens isolated in US clinical microbiology laboratories from 1996 to 2000: results from The Surveillance Network (TSN) Database-USA

Ceftriaxone was introduced into clinical practice in the USA in 1985 and was the first extended-spectrum (third-generation) cephalosporin approved for once-daily treatment of patients with Gram-positive or Gram-negative infections. Review of ceftriaxone activity is important given its continued use since the mid-1980s and reports of emerging resistance among all antimicrobial agent classes. We reviewed the activity of ceftriaxone and relevant comparative agents against five Gram-positive and 11 Gram-negative species for a 5-year period, 1996-2000, using data from The Surveillance Network (TSN) Database-USA. All MIC results were interpreted using NCCLS breakpoint criteria. Ceftriaxone resistance among isolates of Streptococcus pneumoniae (n=17219) remained essentially unchanged over the 5 years studied and in fact was lower from 1998 to 2000 (5.0-5.1%) than in 1996 (6.3%) and 1997 (6.6%). Ceftriaxone resistance (range, 5.1-6.9%) among viridans group streptococci (n=6621) varied by <2% from 1997 to 2000. Beta-lactam-resistant Streptococcus pyogenes (n=935) and group B beta-haemolytic streptococci (n=2267) were not identified in any year. Among methicillin-susceptible Staphylococcus aureus (n=39 284) ceftriaxone resistance was 0.1-0.3% per year from 1996 to 2000. Ceftriaxone resistance among Escherichia coli (n=472407; range, 0.2-0.4%), Klebsiella oxytoca (n=16231; range, 3.5-4.8%), Klebsiella pneumoniae (n=117754; range, 1.9-2.6%), Proteus mirabilis (n=67692; range, 0.2-0.3%), Morganella morganii (n=11251; range, 0.3-2.1%) and Serratia marcescens (n=26519; range, 1.6-3.8%) was low and consistent from 1996 to 2000. Resistance to ceftriaxone among Enterobacter cloacae (n=48114; range, 21.7-23.9%) was relatively high, compared with other Enterobacteriaceae, but unchanged from 1996 to 2000. Rates of resistance to ceftriaxone among Acinetobacter spp. (n=20813) increased from 24.8% in 1996 to 45.1% in 2000. All Haemophilus influenzae (n=7911) and Neisseria gonorrhoeae (n=218) were susceptible to ceftriaxone, as were 99.7% of Moraxella catarrhalis (n=312) tested in 1996 and 1997. In summary, ceftriaxone has retained its potent activity against the most commonly encountered Gram-positive and Gram-negative human pathogens despite widespread and ongoing clinical use for more than 15 years.

In vitro activity of levofloxacin against contemporary clinical isolates of Legionella pneumophila, Mycoplasma pneumoniae and Chlamydia pneumoniae from North America and Europe

OBJECTIVE

To assess the activities of levofloxacin and the comparator agents erythromycin, clarithromycin, azithromycin and doxycycline against atypical respiratory pathogens.

METHODS

One hundred and forty-six Legionella pneumophila, 41 Mycoplasma pneumoniae and nine Chlamydia pneumoniae isolates were procured from various culture collections in North America and Europe and tested for susceptibility to the above agents by broth microdilution. The isolates came primarily from clinical sources and were collected from patients between 1995 and 1999.

RESULTS

Against L. pneumophila, levofloxacin was the most active agent, with an MIC(90) of 0.03 mg/L, twofold more active than clarithromycin (0.06 mg/L), 16-fold more active than erythromycin and azithromycin (0.5 mg/L) and 64-fold more active than doxycycline. Against M. pneumoniae, azithromycin (MIC(90) < or = 0.0005 mg/L) was the most active agent. However, two isolates of M. pneumoniae, one from the USA and one from Finland, were macrolide resistant (MIC > or = 4 mg/L), but levofloxacin susceptible (MIC 0.25 mg/L). The geographic origin of L. pneumophila and M. pneumoniae did not affect the MIC range for any antimicrobial agent tested. Against C. pneumoniae, clarithromycin was the most active agent, with an MIC range of < or =0.008-0.03 mg/L.

CONCLUSIONS

Levofloxacin had comparable activity to the other agents tested against the atypical respiratory pathogens, confirming its potential as an alternative for empirical therapy of community-acquired pneumonia.

Antimicrobial resistance among respiratory pathogens collected in Thailand during 1999-2000

A multi-center surveillance study was conducted in Thailand during 1999-2000 to determine antimicrobial susceptibilities among the respiratory pathogens Streptococcus pneumoniae (n = 206), Haemophilus influenzae (n = 305), and Moraxella catarrhalis (n = 39). Of the S. pneumoniae isolates collected, 33.5% were penicillin-susceptible, 27.2% intermediate and 39.3% resistant. Expectedly, resistance rates to beta-lactams were higher among penicillin-resistant (ceftriaxone, 14.8%; amoxicillin-clavulanate, 42.0%; cefuroxime, 100%) than penicillin-susceptible (ceftriaxone, 0%; amoxicillin-clavulanate, 0%; cefuroxime, 0%) isolates. Likewise, azithromycin and clarithromycin resistances were 4.3% and 5.8% among penicillin-susceptible isolates, and 77.8% and 95.1% among penicillin-resistant isolates. All S. pneumoniae remained susceptible to vancomycin and 99.5% were susceptible to levofloxacin. Multidrug resistance (resistance to >3 antimicrobial classes) was present in 25.2% of pneumococcal isolates (n = 52), with resistance to azithromycin, penicillin and trimethoprim-sulfamethoxazole the most common phenotype (40/52 isolates; 77.0%). Among the isolates of H. influenzae, the prevalence of beta-lactamase production was 45.2%. All isolates of H. influenzae were susceptible to amoxicillin-clavulanate, azithromycin, ceftriaxone, cefuroxime and levofloxacin while 49.5% were resistant to trimethoprim-sulfamethoxazole. All 39 isolates of M. catarrhalis produced beta-lactamase. Azithromycin (MIC90, < or = 0.03 microg/ml) and levofloxacin (MIC90, 0.03 microg/ml) were the most active agents tested against M. catarrhalis. The results of this study may serve as a baseline for future studies to monitor antimicrobial susceptibilities among respiratory pathogens in Thailand.