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Group B Streptococcus (GBS) was the main causative organism of invasive infections in newborns due to vertical transmission from the colonized mothers. The study was undertaken to determine colonization rate, serotype distribution, genotypic characterization, antibiotic susceptibility profiles and molecular characteristics of erythromycin-resistant strains of GBS in pregnant women in Beijing, China. Vaginal rectal swabs were collected from a total of 2850 pregnant women at 35-37 weeks of gestation, in which 7.1% were GBS positive. Serotypes III, Ia and V predominated. All isolates were penicillin susceptible, whereas the resistance rates for erythromycin and clindamycin were strikingly high.     

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In recent years, matrix-assisted laser desorption-ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) has proved a rapid and reliable method for the identification of bacteria and yeasts that have already been isolated. The objective of this study was to evaluate this technology as a routine method for the identification of microorganisms directly from blood culture bottles (BCBs), before isolation, in a large collection of samples. For this purpose, 1000 positive BCBs containing 1085 microorganisms have been analysed by conventional phenotypic methods and by MALDI-TOF MS. Discrepancies have been resolved using molecular methods: the amplification and sequencing of the 16S rRNA gene or the Superoxide Dismutase gene (sodA) for streptococcal isolates. MALDI-TOF predicted a species- or genus-level identification of 81.4% of the analysed microorganisms. The analysis by episode yielded a complete identification of 814 out of 1000 analysed episodes (81.4%). MALDI-TOF identification is available for clinicians within hours of a working shift, as oppose to 18 h later when conventional identification methods are performed. Moreover, although further improvement of sample preparation for polymicrobial BCBs is required, the identification of more than one pathogen in the same BCB provides a valuable indication of unexpected pathogens when their presence may remain undetected in Gram staining. Implementation of MALDI-TOF identification directly from the BCB provides a rapid and reliable identification of the causal pathogen within hours.

A comparative study of clinical Aeromonas dhakensis and Aeromonas hydrophila isolates in southern Taiwan: A. dhakensis is more predominant and virulent

P.-L. Chen¹,², C.-J. Wu²,³, C.-S. Chen⁴, P.-J. Tsai⁵,⁶, H.-J. Tang⁷,⁸ and W.-C. Ko¹,⁹1) Department of Internal Medicine, National Cheng Kung University Hospital, Tainan, Taiwan, 2) Graduate Institute of Clinical Medicine, National Cheng Kung University College of Medicine, Tainan, Taiwan, 3) National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Tainan, Taiwan, 4) Department of Biochemistry and Molecular Biology, National Cheng Kung University College of Medicine, Tainan, Taiwan, 5) Department of Medical Laboratory Science and Biotechnology, National Cheng Kung University College of Medicine, Tainan, Taiwan, 6) Research Centre of Infectious Disease and Signalling, National Cheng Kung University, Tainan, Taiwan, 7) Department of Medicine, Chi Mei Medical Centre, Tainan, Taiwan, 8) Department of Health and Nutrition, Chia Nan University of Pharmacy and Science, Tainan, Taiwan and 9) Department of Medicine, National Cheng Kung University College of Medicine, Tainan, TaiwanOriginal Submission: 2 August 2013; Revised Submission: 9 November 2013; Accepted: 9 November 2013Article published online: 16 December 2013

Abstract

Aeromonas dhakensis, often phenotypically identified as Aeromonas hydrophila, is an important human pathogen. The present study aimed to compare the clinical and biological features of A. dhakensis and A. hydrophila isolates from human wounds. A total of 80 Aeromonas wound isolates collected between January 2004 and April 2011 were analysed. The species was identified by the DNA sequence matching of rpoD and gyrB (or rpoB if necessary). Most of the Aeromonas isolates were identified as A. dhakensis (37, 46.3%), and 13 (16.3%) as A. hydrophila. Both species alone can cause severe skin and soft-tissue infections. More A. dhakensis isolates were found in wounds exposed to environmental water (32.4% vs 0%, p 0.042). More biofilm formation was noted among A. dhakensis isolates (mean optical density at 570 nm, 1.23 ± 0.09 vs 0.78 ± 0.21, p 0.03). The MICs of ceftriaxone, imipenem and gentamicin for A. dhakensis isolates were higher (p <0.0001, <0.04, and <0.01, respectively). The survival rates of Caenorhabditis elegans co-incubated with A. dhakensis from day 1 to day 3 were lower than those of worms infected with A. hydrophila in liquid toxicity assays (all p values <0.01). Isolates of A. dhakensis exhibited more cytotoxicity, as measured by the released leucocyte lactate dehydrogenase levels in human normal skin fibroblast cell lines (29.6 ± 1.2% vs 20.6 ± 0.6%, p <0.0001). The cytotoxin gene ast was primarily present in A. hydrophila isolates (100% vs 2.7%, p <0.0001). In summary, A. dhakensis is the predominant species among Aeromonas wound isolates, and more virulent than A. hydrophila.

Extension of the Legionella pneumophila sequence-based typing scheme to include strains carrying a variant of the N-acylneuraminate cytidylyltransferase gene

M. Mentasti¹, A. Underwood², C. Lück³, N. A. Kozak-Muiznieks⁴, T. G. Harrison¹ and N. K. Fry¹1) Respiratory and Vaccine Preventable Bacteria Reference Unit, 2) Applied Laboratory and Bioinformatics Unit, Public Health England, London, UK, 3) Institut für Medizinische Mikrobiologie und Hygiene, TU Dresden, Dresden, Germany and 4) Centers for Disease Control and Prevention, Atlanta, GA, USAOriginal Submission: 1 May 2013; Revised Submission: 12 November 2013; Accepted: 12 November 2013Article published online: 12 December 2013

Abstract

Sequence-based typing (SBT) combined with monoclonal antibody subgrouping of Legionella pneumophila isolates is at present considered to be the reference standard during epidemiological investigation of Legionnaires‘ disease outbreaks. In some isolates of L. pneumophila, the seventh allele of the standard SBT scheme, neuA, is not amplified, because a homologue that is refractory to amplification with the standard neuA primers is present. Consequently, a complete seven-allele profile, and hence a sequence type, cannot be obtained. Subsequently, primers were designed to amplify both neuA and the homologue, but these yielded suboptimal sequencing results. In this study, novel primers specific for the neuA homologue were designed and internationally validated by members of the ESCMID Study Group for Legionella Infections at national and regional Legionella reference laboratories with a modified version of the online L. pneumophila sequence quality tool. To date, the addition of the neuAh target to the SBT protocol has allowed full typing data to be obtained for 108 isolates of 11 different serogroups, namely 1, 2, 3, 4, 5, 6, 7, 8, 10, 13, and 14, which could not previously be typed with the standard SBT neuA primers. Further studies are necessary to determine why it is still not possible to obtain either a neuA or a neuAh allele from three serogroup 11 isolates.     

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Extended-spectrum β-lactamase (ESBL) -producing Enterobacteriaceae have been notifiable according to the Swedish Communicable Disease Act since 2007. A major increase in the number of cases has been observed, with 2099 cases in 2007 and 7225 cases in 2012. The majority of the isolates are Escherichia coli. Additionally, Swedish data on the prevalence of ESBL-producing invasive isolates of E. coli are available through EARS-Net, and through biannual point prevalence studies, where molecular characterization of isolates from the entire country is carried out. This paper describes major trends in the Swedish epidemiology of ESBL-producing E. coli in the period 2007–2012. Isolates from the point prevalence studies were subjected to antimicrobial susceptibility testing, ESBL genotyping, pulsed-field gel electrophoresis, multi-locus sequence typing and phylogenetic grouping with PCR. The distribution of sequence types, resistance genes and susceptibility levels were all stable over the three study periods. The dominating resistance gene conferring ESBL was bla_CTX-M-15, found in 54–58% of the isolates. ST131 represented 34–38% of the isolates. Other major sequence types were ST38, ST69, ST405, ST617 and ST648, each representing 2–6% of the isolates. Phylogenetic group B2 was the most common, and was observed in 41–47% of the isolates. However, among ST131 isolates the B2 phylogenetic group represented 90–98% of the isolates. The most important epidemiological difference seen over time was that the median age of infected women decreased from 62 to 52 years (p <0.0001) and infected men from 67 to 64 years. A potential explanation might be the shift towards a higher proportion of community-acquired infections in individuals lacking comorbidities.

Validation of EUCAST zone diameter breakpoints against reference broth microdilution

S. Bengtsson¹, C. Bjelkenbrant¹ and G. Kahlmeter^1,21) Department of Clinical Microbiology, Central Hospital, Växjö and 2) Department of Medical Sciences, Division of Clinical Bacteriology, Uppsala University, Uppsala, SwedenOriginal Submission: 30 May 2013; Revised Submission: 28 August 2013; Accepted: 25 September 2013Editor: R. CantonArticle published online: 13 November 2013Clin Microbiol Infect 2014; 20: O353–O36010.1111/1469-0691.12414

Abstract

The European Committee on Antimicrobial Susceptibility Testing (EUCAST) began harmonizing clinical breakpoints in Europe 2002. In 2009, work to develop a disc diffusion method began and the first disc diffusion breakpoints calibrated to EUCAST clinical MIC breakpoints were published in December 2009. In this study we validated EUCAST clinical zone diameter breakpoints against the International Standard Organization (ISO) reference broth microdilution. A collection of 544 isolates (238 Gram-negative and 306 Gram-positive) were tested against a panel of antimicrobial agents. Antimicrobial susceptibility testing was performed with broth microdilution as described by ISO and disc diffusion in accordance with EUCAST methodology. Inhibition zone diameters and MIC values were interpreted and categorized (S, I and R) according to EUCAST clinical breakpoint table version 2.0. Categorical agreement (CA) as well as minor (mD), major (MD) and very major (VMD) discrepancies were determined. There was in general good correlation between susceptibility test results obtained with disc diffusion and broth microdilution. Overall CA was 97.3% for all combinations of organisms and antimicrobial agents (<n = 5231) and the overall discrepancy rates were 110 (2.1%) mD, 24 (0.5%) MD and 7 (0.1%) VMD. The overall CA for Gram-positive and Gram-negative organisms were 98.7% (2346 tests) and 96.2% (2942 tests), respectively. Seven VMD were observed, five for Gram-positive organisms (coagulase negative staphylococci (<n = 2) and Staphylococcus aureus (<n = 3)) and two for Gram-negative organisms (<Pseudomonas aeruginosa). Minor discrepancies were mainly observed in Gram-negatives and were related to different antimicrobial agents and species.

Increased in vitro fitness of multi- and extensively drug-resistant F15/LAM4/KZN strains of Mycobacterium tuberculosis

C. C. Naidoo and M. PillayMedical Microbiology and Infection Control, School of Laboratory Medicine and Medical Sciences, College of Health Sciences, University of KwaZulu-Natal, Durban, South AfricaOriginal Submission: 21 May 2013; Revised Submission: 7 August 2013; Accepted: 27 September 2013 Editor: D. RaoultArticle published online: 18 November 2013Clin Microbiol Infect 2014; 20: O361–O36910.1111/1469-0691.12415

Abstract

The role of fitness in transmission of drug-resistant strains has been explored in previous studies; but has not been established for F15/LAM4/KZN strains, which were responsible for the extensively drug-resistant tuberculosis (XDR-TB) outbreak in Tugela Ferry, South Africa. The biological fitness of 15 clinical strains representing the F15/LAM4/KZN, Beijing, F11 and F28 families was determined by growth, viability and competition assays and correlated with DNA sequencing of eight genes associated with drug resistance and putative compensatory mechanisms. Similar growth rates were observed among susceptible, multidrug-resistant (MDR) and XDR strains of the KZN and F28 genotypes. In contrast, Beijing and F11 MDR strains demonstrated significantly reduced fitness. Resistant strains exhibited heterogeneous fitness profiles in competition with different susceptible strains, suggesting strain dependence. In addition, co-culture growth rates were consistently higher than independent growth rates in 13/14 competition pairs. All 14 drug-resistant strains retained viability, at a low CFU/mL, when paired with susceptible strains. The persistence of such resistant strains could consequently support the acquisition of additional drug-resistance-conferring mutations and/or the evolution of compensatory mechanisms. Frequently occurring mutations were detected in KZN and F28 resistant strains whereas, the Beijing MDR strain harboured a less common katG mutation and the F11 MDR strain had no katG mutation. Contrary to drug-resistant Beijing and F11 strains, the successful transmission of KZN strains, particularly during the outbreak, may be attributed to the presence of drug-resistance-conferring mutations associated with little or no associated fitness costs. Amplified growth in co-culture may be suggestive of in vivo trans-complementation.     

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Three Brucella abortus strains were isolated from joint hygromas from cows in northern Togo. Two deletions in the 5′ side of the gene BruAb2_0168 were identified. As this gene is used for species identification, these deletions have consequences for diagnostic procedures. Multiple locus variable number of tandem repeat (VNTR) analysis was therefore performed for species identification. The strains showed unique VNTR profiles, providing some of the first genotypic data from West Africa. More molecular and epidemiological data are needed from the region, in order to better understand transmission patterns and develop suitable diagnostic assays.

Trends in antimicrobial non-susceptibility in methicillin-resistant Staphylococcus aureus from Germany (2004–2011)

F. Schaumburg¹, E. A. Idelevich¹, G. Peters¹, A. Mellmann², C. von Eiff^1,3, K. Becker¹ and Study Group1) Institute of Medical Microbiology, University Hospital Münster, 2) Institute of Hygiene, University Hospital Münster, Münster and 3) Pfizer Pharma GmbH, Berlin, GermanyOriginal Submission: 12 November 2013; Revised Submission: 17 December 2013; Accepted: 20 December 2013Editor: G. LinaArticle published online: 27 December 2013Clin Microbiol Infect 2014; 20: O554–O557

Abstract

We analysed trends in antimicrobial non-susceptibility in methicillin-resistant Staphylococcus aureus (MSRA) from Germany to assess the impact of the changing population structure of MRSA on antimicrobial resistance rates. During two large nationwide multicentre studies in 2004–2005 and 2010–2011, we collected consecutively spa-genotyped MRSA isolates. The increase in non-susceptibility rates for tetracycline and trimethoprim–sulphamethoxazole was associated with the spread of livestock-associated MRSA. A decrease in non-susceptibility rates for aminoglycosides and quinolones affected all major lineages (spa-clonal complexes 003, 008, and 032). All isolated remained susceptible to glycopeptides and linezolid.     

Online-Only Abstract: Population-based burden of bloodstream infections in Finland

Bloodstream infections (BSI) are a major cause of mortality, morbidity and medical cost, but few population-based studies have concomitantly evaluated BSI incidence and mortality. Data on BSI episodes reported to national, population-based surveillance by all clinical microbiology laboratories in Finland during 2004-07 were linked to vital statistics. Age-, sex and microbe-specific incidence and mortality rates were calculated. During 2004-07, 33 473 BSI episodes were identified; BSI incidence increased from 147 to 168 per 100 000 population (average annual increase, 4.4%; p <0.001). Rates were highest among persons ±65 years and <1 year, and higher among male patients than female patients (166 versus 152 per 100 000). The most common aetiologies were Escherichia coli (27%) and Staphylococcus aureus (13%). Among male patients, 52% of BSI were caused by gram-positive bacteria compared with 42% among female patients (p <0.001). The overall 30-day case-fatality was 13%. Of the deaths, 32% occurred within 2 days, 70% were among people aged 65 years or more and 33% were caused by E. coli or S. aureus infections. The BSI mortality rate increased from 19 to 22 per 100 000 (average annual increase: 4.0%, p 0.01). Among people aged 25 years or more, the mortality rate was 1.4-fold higher in men than women (34 versus 25 per 100 000 population). Overall excess annual mortality from BSI in the population was 18 per 100 000. The substantial BSI burden among the elderly and among adult men highlights the need for developing and implementing effective interventions, particularly for BSI caused by E. coli and S. aureus. One-third of BSI deaths occurred early, emphasizing the importance of early identification and treatment.     

Online-Only Abstract: Population-based burden of bloodstream infections in Finland

Hand, foot and mouth disease (HFMD) and herpangina (HA) are frequently caused by several distinct serotypes belonging to the human enterovirus A species (HEVA). Enterovirus 71 is considered as a significant public health threat because of rare but fatal neurological complications. A sentinel surveillance system involving paediatricians from Clermont-Ferrand (France) was set up to determine the clinical and epidemiological characteristics of HFMD/HA associated with enterovirus infections. A standardized report form was used to collect demographic and clinical data. Throat or buccal specimens were obtained prospectively and tested for the presence of enteroviruses. The frequency of HEVA serotypes was determined by genotyping. Phylogenetic relationships were analysed to identify potential new virus variants. From 1 April to 31 December 2010, a total of 222 children were enrolled. The predominant clinical presentation was HA (63.8%) and this was frequently associated with clinical signs of HFMD (48%). An enterovirus infection was diagnosed in 143 (64.4%) patients and serotype identification was achieved in 141/143 (98.6%). The predominant serotypes were coxsackievirus A10 (39.9%) and A6 (28%), followed by coxsackievirus A16 (17.5%) and enterovirus 71 (6.3%). Fever was observed in 115 (80.4%) children. No patient had neurological complications. Coxsackievirus A10 and A6 strains involved in the outbreak were consistently genetically related with those detected earlier in Finland and constituted distinct European lineages. Although several enterovirus serotypes have been involved in HFMD/HA cases, the outbreak described in this population survey was caused by coxsackievirus A6 and coxsackievirus A10, the third dual outbreak in Europe in the last 3 years.     

Online-Only Abstract: Population-based burden of bloodstream infections in Finland

We assessed the comparative efficacy of empirical therapy with beta-lactam plus macrolide vs. beta-lactam plus doxycycline for the treatment of community-acquired pneumonia (CAP) among patients in the Australian Community-Acquired Pneumonia Study. Both regimens demonstrated similar outcomes against CAP due to either ‘atypical’ (Chlamydophila, Legionella or Mycoplasma spp.) or typical bacterial pathogens.     

Online-Only Abstract: Population-based burden of bloodstream infections in Finland

Clinical breakpoints are used in clinical microbiology laboratories to categorize microorganisms as clinically susceptible (S), intermediate (I) or resistant (R) dependent on the quantitative antimicrobial susceptibility as indicated by the MIC value determined in a well-defined standard test system. The laboratory report, with the designations of S, I or R for each antimicrobial agent, provides guidance to clinicians with respect to the potential use of agents in the treatment of patients, and clinical breakpoints should therefore distinguish between patients that are likely or unlikely to respond to antimicrobial treatment. In Europe, clinical breakpoints are set by the European Committee on Antimicrobial Susceptibility Testing (EUCAST), following a defined procedure. This includes evaluation of efficacy in experimental settings and clinical studies to derive pharmacodynamic targets such as the fAUC/MIC ratio or %fT > MIC required for efficacy, the pharmacokinetic properties of the agent, Monte Carlo simulations to estimate exposures of the antimicrobial agent in the target patient population and commonly used dosing regimens. The probability of target attainment is subsequently determined for a range of pharmacodynamic targets and the results from the Monte Carlo simulations. The breakpoints derived are subsequently evaluated with respect to the wild-type population of the target microorganisms, specific resistance mechanisms and other relevant data. In this paper, we provide an overview of the EUCAST process and considerations for setting pharmacokinetic/pharmacodynamic breakpoints. These are the breakpoints that in the EUCAST breakpoint tables are referred to as ‘non-species-related breakpoints'.     

AIDS: is a safe vaccine readily available?

Intense efforts are presently being made world-wide to produce an efficient AIDS vaccine. Based on a review of current medical research and scientific papers, a strategy to obtain quickly an effective, safe and marketable AIDS Vaccine with available monoclonal antibodies is described.     

Opinion article: cytomegalovirus is a risk factor in atherogenesis

Whether or not infectious agents are involved in the pathogenesis of atherosclerosis has been a matter of discussion for the past 2 decades. Although there is no definite proof of a causal role of human cytomegalovirus in atherogenesis, a body of knowledge supports the concept that this virus is involved in the development of atherosclerotic lesions. This review assesses the most important data published in support of this hypothesis.     

Evidence at a glance: error matrix approach for overviewing available evidence

Background  

Clinical evidence continues to expand and is increasingly difficult to overview. We aimed at conceptualizing a visual assessment tool, i.e., a matrix for overviewing studies and their data in order to assess the clinical evidence at a glance.     

Web quality control for lectures: Supercourse and Amazon.com

Peer review has been at the corner stone of quality control of the biomedical journals in the past 300 years. With the emergency of the Internet, new models of quality control and peer review are emerging. However, such models are poorly investigated. We would argue that the popular system of quality control used in Amazon.com offers a way to ensure continuous quality improvement in the area of research communications on the Internet. Such system is providing an interesting alternative to the traditional peer review approaches used in the biomedical journals and challenges the traditional paradigms of scientific publishing. This idea is being explored in the context of Supercourse, a library of 2,350 prevention lectures, shared for free by faculty members from over 150 countries. Supercourse is successfully utilizing quality control approaches that are similar to Amazon.com model. Clearly, the existing approaches and emerging alternatives for quality control in scientific communications needs to be assessed scientifically. Rapid explosion of internet technologies could be leveraged to produce better, more cost effective systems for quality control in the biomedical publications and across all sciences.     

Present options for treating sperm autoimmunity before proteomic analysis is available: reply

Dear Sir, We would like to thank Dr Check for his kind comments and hisexcellent and valuable additions to our article. On the basis of previous results of his group, Dr Check quotesthe advantages of inrauterine insemination (IUI) in immune infertilitydue     

Research-overview article: membrane lipolysis and cholinergic priority.

Cholinergic drugs and antigenic and toxicological challenges induced lipolysis in twelve sheep. A lipolytic end product, the PGF2alpha metabolite, was found to be a reliable non-specific cholinergic marker. The lipolytic membrane alterations supported the concept of a general priority of the cholinergic system. A main feature is the breaking of molecular stability in dynamic hydrogen-bond interactions. Both acetylcholine and dioxygen reactivity are apparently moderated by cholinesterases. Free radicals appeared to be normal intermediates of catabolism, serving to neutralize excess protons. Antioxidants regenerate molecular oxygen, and so counteract part of excess activated oxygen. Intrinsic reactivity against its own structures characterizes the immuno-cholinergic system. Genetic priority could be assumed for cholinergic constituents and constitutions. A broad spectrum of etiologies was suggested. Lasting or repeated challenges may cause heterochiral conversions of vital proteins. The priority aspect of cholinergism also suggested methods to rank among the multitude of secondary biomolecules.